Fix #1921

(cherry picked from commit d34fa2bcc3)
Signed-off-by: Domen Kožar <domen@dev.si>

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,27 @@
+<!--
+
+# Filing a Nix issue
+
+*WAIT* Are you sure you're filing your issue in the right repository?
+
+We appreciate you taking the time to tell us about issues you encounter, but routing the issue to the right place will get you help sooner and save everyone time.
+
+This is the Nix repository, and issues here should be about Nix the build and package management *_tool_*.
+
+If you have a problem with a specific package on NixOS or when using Nix, you probably want to file an issue with _nixpkgs_, whose issue tracker is over at https://github.com/NixOS/nixpkgs/issues.
+
+Examples of _Nix_ issues:
+
+- Nix segfaults when I run `nix-build -A blahblah`
+- The Nix language needs a new builtin: `builtins.foobar`
+- Regression in the behavior of `nix-env` in Nix 2.0
+
+Examples of _nixpkgs_ issues:
+
+- glibc is b0rked on aarch64
+- chromium in NixOS doesn't support U2F but google-chrome does!
+- The OpenJDK package on macOS is missing a key component
+
+Chances are if you're a newcomer to the Nix world, you'll probably want the [nixpkgs tracker](https://github.com/NixOS/nixpkgs/issues). It also gets a lot more eyeball traffic so you'll probably get a response a lot more quickly.
+
+-->

.gitignore

@@ -38,6 +38,7 @@ perl/Makefile.config
 /scripts/nix-copy-closure
 /scripts/nix-reduce-build
 /scripts/nix-http-export.cgi
+/scripts/nix-profile-daemon.sh
 
 # /src/libexpr/
 /src/libexpr/lexer-tab.cc
@@ -99,16 +100,20 @@ perl/Makefile.config
 /misc/systemd/nix-daemon.socket
 /misc/upstart/nix-daemon.conf
 
+/src/resolve-system-dependencies/resolve-system-dependencies
+
 inst/
 
 *.a
 *.o
 *.so
+*.dylib
 *.dll
 *.exe
 *.dep
 *~
 *.pc
+*.plist
 
 # GNU Global
 GPATH

.travis.yml

@@ -0,0 +1,2 @@
+os: osx
+script: ./tests/install-darwin.sh

Makefile

@@ -23,9 +23,9 @@ makefiles = \
   misc/systemd/local.mk \
   misc/launchd/local.mk \
   misc/upstart/local.mk \
-  misc/emacs/local.mk \
   doc/manual/local.mk \
-  tests/local.mk
+  tests/local.mk \
+  tests/plugins/local.mk
 
 GLOBAL_CXXFLAGS += -std=c++14 -g -Wall -include config.h
 

Makefile.config.in

@@ -6,6 +6,8 @@ CXXFLAGS = @CXXFLAGS@
 ENABLE_S3 = @ENABLE_S3@
 HAVE_SODIUM = @HAVE_SODIUM@
 HAVE_READLINE = @HAVE_READLINE@
+HAVE_BROTLI = @HAVE_BROTLI@
+HAVE_SECCOMP = @HAVE_SECCOMP@
 LIBCURL_LIBS = @LIBCURL_LIBS@
 OPENSSL_LIBS = @OPENSSL_LIBS@
 PACKAGE_NAME = @PACKAGE_NAME@
@@ -13,9 +15,10 @@ PACKAGE_VERSION = @PACKAGE_VERSION@
 SODIUM_LIBS = @SODIUM_LIBS@
 LIBLZMA_LIBS = @LIBLZMA_LIBS@
 SQLITE3_LIBS = @SQLITE3_LIBS@
+LIBBROTLI_LIBS = @LIBBROTLI_LIBS@
 bash = @bash@
 bindir = @bindir@
-bro = @bro@
+brotli = @brotli@
 lsof = @lsof@
 datadir = @datadir@
 datarootdir = @datarootdir@

configure.ac

@@ -61,6 +61,7 @@ CFLAGS=
 CXXFLAGS=
 AC_PROG_CC
 AC_PROG_CXX
+AC_PROG_CPP
 AX_CXX_COMPILE_STDCXX_11
 
 
@@ -127,7 +128,7 @@ NEED_PROG(gzip, gzip)
 NEED_PROG(xz, xz)
 AC_PATH_PROG(dot, dot)
 AC_PATH_PROG(pv, pv, pv)
-AC_PATH_PROG(bro, bro, bro)
+AC_PATH_PROGS(brotli, brotli bro, bro)
 AC_PATH_PROG(lsof, lsof, lsof)
 
 
@@ -174,23 +175,51 @@ AC_SUBST(HAVE_SODIUM, [$have_sodium])
 
 # Look for liblzma, a required dependency.
 PKG_CHECK_MODULES([LIBLZMA], [liblzma], [CXXFLAGS="$LIBLZMA_CFLAGS $CXXFLAGS"])
+AC_CHECK_LIB([lzma], [lzma_stream_encoder_mt],
+  [AC_DEFINE([HAVE_LZMA_MT], [1], [xz multithreaded compression support])])
 
 
+# Look for libbrotli{enc,dec}, optional dependencies
+PKG_CHECK_MODULES([LIBBROTLI], [libbrotlienc libbrotlidec],
+  [AC_DEFINE([HAVE_BROTLI], [1], [Whether to use libbrotli.])
+   CXXFLAGS="$LIBBROTLI_CFLAGS $CXXFLAGS"]
+   have_brotli=1], [have_brotli=])
+AC_SUBST(HAVE_BROTLI, [$have_brotli])
+
 # Look for libseccomp, required for Linux sandboxing.
 if test "$sys_name" = linux; then
-  PKG_CHECK_MODULES([LIBSECCOMP], [libseccomp],
-                    [CXXFLAGS="$LIBSECCOMP_CFLAGS $CXXFLAGS"])
+  AC_ARG_ENABLE([seccomp-sandboxing],
+                AC_HELP_STRING([--disable-seccomp-sandboxing],
+                               [Don't build support for seccomp sandboxing (only recommended if your arch doesn't support libseccomp yet!)]
+                              ))
+  if test "x$enable_seccomp_sandboxing" != "xno"; then
+    PKG_CHECK_MODULES([LIBSECCOMP], [libseccomp],
+                      [CXXFLAGS="$LIBSECCOMP_CFLAGS $CXXFLAGS"])
+    have_seccomp=1
+    AC_DEFINE([HAVE_SECCOMP], [1], [Whether seccomp is available and should be used for sandboxing.])
+  else
+    have_seccomp=
+  fi
+else
+  have_seccomp=
 fi
+AC_SUBST(HAVE_SECCOMP, [$have_seccomp])
 
 
 # Look for aws-cpp-sdk-s3.
 AC_LANG_PUSH(C++)
 AC_CHECK_HEADERS([aws/s3/S3Client.h],
-  [AC_DEFINE([ENABLE_S3], [1], [Whether to enable S3 support via aws-cpp-sdk-s3.])
+  [AC_DEFINE([ENABLE_S3], [1], [Whether to enable S3 support via aws-sdk-cpp.])
   enable_s3=1], [enable_s3=])
 AC_SUBST(ENABLE_S3, [$enable_s3])
 AC_LANG_POP(C++)
 
+if test -n "$enable_s3"; then
+  declare -a aws_version_tokens=($(printf '#include <aws/core/VersionConfig.h>\nAWS_SDK_VERSION_STRING' | $CPP - | grep -v '^#.*' | sed 's/"//g' | tr '.' ' '))
+  AC_DEFINE_UNQUOTED([AWS_VERSION_MAJOR], ${aws_version_tokens@<:@0@:>@}, [Major version of aws-sdk-cpp.])
+  AC_DEFINE_UNQUOTED([AWS_VERSION_MINOR], ${aws_version_tokens@<:@1@:>@}, [Minor version of aws-sdk-cpp.])
+fi
+
 
 # Whether to use the Boehm garbage collector.
 AC_ARG_ENABLE(gc, AC_HELP_STRING([--enable-gc],

corepkgs/fetchurl.nix

@@ -1,10 +1,10 @@
-{ system ? builtins.currentSystem
+{ system ? "" # obsolete
 , url
-, md5 ? "", sha1 ? "", sha256 ? ""
+, md5 ? "", sha1 ? "", sha256 ? "", sha512 ? ""
 , outputHash ?
-    if sha1 != "" then sha1 else if md5 != "" then md5 else sha256
+    if sha512 != "" then sha512 else if sha1 != "" then sha1 else if md5 != "" then md5 else sha256
 , outputHashAlgo ?
-    if sha1 != "" then "sha1" else if md5 != "" then "md5" else "sha256"
+    if sha512 != "" then "sha512" else if sha1 != "" then "sha1" else if md5 != "" then "md5" else "sha256"
 , executable ? false
 , unpack ? false
 , name ? baseNameOf (toString url)
@@ -17,7 +17,9 @@ derivation {
   inherit outputHashAlgo outputHash;
   outputHashMode = if unpack || executable then "recursive" else "flat";
 
-  inherit name system url executable unpack;
+  inherit name url executable unpack;
+
+  system = "builtin";
 
   # No need to double the amount of network traffic
   preferLocalBuild = true;

doc/manual/advanced-topics/distributed-builds.xml

@@ -4,71 +4,109 @@
       version="5.0"
       xml:id='chap-distributed-builds'>
 
-<title>Distributed Builds</title>
+<title>Remote Builds</title>
 
-<para>Nix supports distributed builds, where a local Nix installation can
-forward Nix builds to other machines over the network.  This allows
-multiple builds to be performed in parallel (thus improving
-performance) and allows Nix to perform multi-platform builds in a
-semi-transparent way.  For instance, if you perform a build for a
-<literal>x86_64-darwin</literal> on an <literal>i686-linux</literal>
-machine, Nix can automatically forward the build to a
-<literal>x86_64-darwin</literal> machine, if available.</para>
+<para>Nix supports remote builds, where a local Nix installation can
+forward Nix builds to other machines.  This allows multiple builds to
+be performed in parallel and allows Nix to perform multi-platform
+builds in a semi-transparent way.  For instance, if you perform a
+build for a <literal>x86_64-darwin</literal> on an
+<literal>i686-linux</literal> machine, Nix can automatically forward
+the build to a <literal>x86_64-darwin</literal> machine, if
+available.</para>
 
-<para>You can enable distributed builds by setting the environment
-variable <envar>NIX_BUILD_HOOK</envar> to point to a program that Nix
-will call whenever it wants to build a derivation.  The build hook
-(typically a shell or Perl script) can decline the build, in which Nix
-will perform it in the usual way if possible, or it can accept it, in
-which case it is responsible for somehow getting the inputs of the
-build to another machine, doing the build there, and getting the
-results back.</para>
+<para>To forward a build to a remote machine, it’s required that the
+remote machine is accessible via SSH and that it has Nix
+installed. You can test whether connecting to the remote Nix instance
+works, e.g.
 
-<example xml:id='ex-remote-systems'><title>Remote machine configuration:
-<filename>remote-systems.conf</filename></title>
-<programlisting>
-nix@mcflurry.labs.cs.uu.nl  x86_64-darwin   /home/nix/.ssh/id_quarterpounder_auto  2
-nix@scratchy.labs.cs.uu.nl  i686-linux      /home/nix/.ssh/id_scratchy_auto        8 1 kvm
-nix@itchy.labs.cs.uu.nl     i686-linux      /home/nix/.ssh/id_scratchy_auto        8 2
-nix@poochie.labs.cs.uu.nl   i686-linux      /home/nix/.ssh/id_scratchy_auto        8 2 kvm perf
-</programlisting>
-</example>
+<screen>
+$ nix ping-store --store ssh://mac
+</screen>
 
-<para>Nix ships with a build hook that should be suitable for most
-purposes.  It uses <command>ssh</command> and
-<command>nix-copy-closure</command> to copy the build inputs and
-outputs and perform the remote build.  To use it, you should set
-<envar>NIX_BUILD_HOOK</envar> to
-<filename><replaceable>prefix</replaceable>/libexec/nix/build-remote</filename>.
-You should also define a list of available build machines and point
-the environment variable <envar>NIX_REMOTE_SYSTEMS</envar> to
-it. <envar>NIX_REMOTE_SYSTEMS</envar> must be an absolute path. An
-example configuration is shown in <xref linkend='ex-remote-systems'
-/>.  Each line in the file specifies a machine, with the following
-bits of information:
+will try to connect to the machine named <literal>mac</literal>. It is
+possible to specify an SSH identity file as part of the remote store
+URI, e.g.
+
+<screen>
+$ nix ping-store --store ssh://mac?ssh-key=/home/alice/my-key
+</screen>
+
+Since builds should be non-interactive, the key should not have a
+passphrase. Alternatively, you can load identities ahead of time into
+<command>ssh-agent</command> or <command>gpg-agent</command>.</para>
+
+<para>If you get the error
+
+<screen>
+bash: nix-store: command not found
+error: cannot connect to 'mac'
+</screen>
+
+then you need to ensure that the <envar>PATH</envar> of
+non-interactive login shells contains Nix.</para>
+
+<warning><para>If you are building via the Nix daemon, it is the Nix
+daemon user account (that is, <literal>root</literal>) that should
+have SSH access to the remote machine. If you can’t or don’t want to
+configure <literal>root</literal> to be able to access to remote
+machine, you can use a private Nix store instead by passing
+e.g. <literal>--store ~/my-nix</literal>.</para></warning>
+
+<para>The list of remote machines can be specified on the command line
+or in the Nix configuration file. The former is convenient for
+testing. For example, the following command allows you to build a
+derivation for <literal>x86_64-darwin</literal> on a Linux machine:
+
+<screen>
+$ uname
+Linux
+
+$ nix build \
+  '(with import &lt;nixpkgs> { system = "x86_64-darwin"; }; runCommand "foo" {} "uname > $out")' \
+  --builders 'ssh://mac x86_64-darwin'
+[1/0/1 built, 0.0 MiB DL] building foo on ssh://mac
+
+$ cat ./result
+Darwin
+</screen>
+
+It is possible to specify multiple builders separated by a semicolon
+or a newline, e.g.
+
+<screen>
+  --builders 'ssh://mac x86_64-darwin ; ssh://beastie x86_64-freebsd'
+</screen>
+</para>
+
+<para>Each machine specification consists of the following elements,
+separated by spaces. Only the first element is required.
 
 <orderedlist>
 
-  <listitem><para>The name of the remote machine, with optionally the
-  user under which the remote build should be performed.  This is
-  actually passed as an argument to <command>ssh</command>, so it can
-  be an alias defined in your
+  <listitem><para>The URI of the remote store in the format
+  <literal>ssh://[<replaceable>username</replaceable>@]<replaceable>hostname</replaceable></literal>,
+  e.g. <literal>ssh://nix@mac</literal> or
+  <literal>ssh://mac</literal>. For backward compatibility,
+  <literal>ssh://</literal> may be omitted. The hostname may be an
+  alias defined in your
   <filename>~/.ssh/config</filename>.</para></listitem>
 
   <listitem><para>A comma-separated list of Nix platform type
   identifiers, such as <literal>x86_64-darwin</literal>.  It is
   possible for a machine to support multiple platform types, e.g.,
-  <literal>i686-linux,x86_64-linux</literal>.</para></listitem>
+  <literal>i686-linux,x86_64-linux</literal>. If omitted, this
+  defaults to the local platform type.</para></listitem>
 
-  <listitem><para>The SSH private key to be used to log in to the
-  remote machine.  Since builds should be non-interactive, this key
-  should not have a passphrase!</para></listitem>
+  <listitem><para>The SSH identity file to be used to log in to the
+  remote machine. If omitted, SSH will use its regular
+  identities.</para></listitem>
 
-  <listitem><para>The maximum number of builds that
-  <filename>build-remote</filename> will execute in parallel on the
-  machine.  Typically this should be equal to the number of CPU cores.
-  For instance, the machine <literal>itchy</literal> in the example
-  will execute up to 8 builds in parallel.</para></listitem>
+  <listitem><para>The maximum number of builds that Nix will execute
+  in parallel on the machine.  Typically this should be equal to the
+  number of CPU cores.  For instance, the machine
+  <literal>itchy</literal> in the example will execute up to 8 builds
+  in parallel.</para></listitem>
 
   <listitem><para>The “speed factor”, indicating the relative speed of
   the machine.  If there are multiple machines of the right type, Nix
@@ -76,30 +114,69 @@ bits of information:
 
   <listitem><para>A comma-separated list of <emphasis>supported
   features</emphasis>.  If a derivation has the
-  <varname>requiredSystemFeatures</varname> attribute, then
-  <filename>build-remote</filename> will only perform the
-  derivation on a machine that has the specified features.  For
-  instance, the attribute
+  <varname>requiredSystemFeatures</varname> attribute, then Nix will
+  only perform the derivation on a machine that has the specified
+  features.  For instance, the attribute
 
 <programlisting>
 requiredSystemFeatures = [ "kvm" ];
 </programlisting>
 
   will cause the build to be performed on a machine that has the
-  <literal>kvm</literal> feature (i.e., <literal>scratchy</literal> in
-  the example above).</para></listitem>
+  <literal>kvm</literal> feature.</para></listitem>
 
   <listitem><para>A comma-separated list of <emphasis>mandatory
   features</emphasis>.  A machine will only be used to build a
   derivation if all of the machine’s mandatory features appear in the
-  derivation’s <varname>requiredSystemFeatures</varname> attribute.
-  Thus, in the example, the machine <literal>poochie</literal> will
-  only do derivations that have
-  <varname>requiredSystemFeatures</varname> set to <literal>["kvm"
-  "perf"]</literal> or <literal>["perf"]</literal>.</para></listitem>
+  derivation’s <varname>requiredSystemFeatures</varname>
+  attribute..</para></listitem>
 
 </orderedlist>
 
-</para>
+For example, the machine specification
+
+<programlisting>
+nix@scratchy.labs.cs.uu.nl  i686-linux      /home/nix/.ssh/id_scratchy_auto        8 1 kvm
+nix@itchy.labs.cs.uu.nl     i686-linux      /home/nix/.ssh/id_scratchy_auto        8 2
+nix@poochie.labs.cs.uu.nl   i686-linux      /home/nix/.ssh/id_scratchy_auto        1 2 kvm benchmark
+</programlisting>
+
+specifies several machines that can perform
+<literal>i686-linux</literal> builds. However,
+<literal>poochie</literal> will only do builds that have the attribute
+
+<programlisting>
+requiredSystemFeatures = [ "benchmark" ];
+</programlisting>
+
+or
+
+<programlisting>
+requiredSystemFeatures = [ "benchmark" "kvm" ];
+</programlisting>
+
+<literal>itchy</literal> cannot do builds that require
+<literal>kvm</literal>, but <literal>scratchy</literal> does support
+such builds. For regular builds, <literal>itchy</literal> will be
+preferred over <literal>scratchy</literal> because it has a higher
+speed factor.</para>
+
+<para>Remote builders can also be configured in
+<filename>nix.conf</filename>, e.g.
+
+<programlisting>
+builders = ssh://mac x86_64-darwin ; ssh://beastie x86_64-freebsd
+</programlisting>
+
+Finally, remote builders can be configured in a separate configuration
+file included in <option>builders</option> via the syntax
+<literal>@<replaceable>file</replaceable></literal>. For example,
+
+<programlisting>
+builders = @/etc/nix/machines
+</programlisting>
+
+causes the list of machines in <filename>/etc/nix/machines</filename>
+to be included. (This is the default.)</para>
 
 </chapter>

doc/manual/command-ref/conf-file.xml

@@ -40,18 +40,22 @@
 
 <para>The configuration files consist of
 <literal><replaceable>name</replaceable> =
-<replaceable>value</replaceable></literal> pairs, one per line.
+<replaceable>value</replaceable></literal> pairs, one per line. Other
+files can be included with a line like <literal>include
+<replaceable>path</replaceable></literal>, where
+<replaceable>path</replaceable> is interpreted relative to the current
+conf file and a missing file is an error unless
+<literal>!include</literal> is used instead.
 Comments start with a <literal>#</literal> character.  Here is an
 example configuration file:</para>
 
 <programlisting>
-gc-keep-outputs = true       # Nice for developers
-gc-keep-derivations = true   # Idem
-env-keep-derivations = false
+keep-outputs = true       # Nice for developers
+keep-derivations = true   # Idem
 </programlisting>
 
 <para>You can override settings on the command line using the
-<option>--option</option> flag, e.g. <literal>--option gc-keep-outputs
+<option>--option</option> flag, e.g. <literal>--option keep-outputs
 false</literal>.</para>
 
 <para>The following settings are currently available:
@@ -59,147 +63,99 @@ false</literal>.</para>
 <variablelist>
 
 
-  <varlistentry xml:id="conf-gc-keep-outputs"><term><literal>gc-keep-outputs</literal></term>
-
-    <listitem><para>If <literal>true</literal>, the garbage collector
-    will keep the outputs of non-garbage derivations.  If
-    <literal>false</literal> (default), outputs will be deleted unless
-    they are GC roots themselves (or reachable from other roots).</para>
-
-    <para>In general, outputs must be registered as roots separately.
-    However, even if the output of a derivation is registered as a
-    root, the collector will still delete store paths that are used
-    only at build time (e.g., the C compiler, or source tarballs
-    downloaded from the network).  To prevent it from doing so, set
-    this option to <literal>true</literal>.</para></listitem>
-
-  </varlistentry>
-
-
-  <varlistentry xml:id="conf-gc-keep-derivations"><term><literal>gc-keep-derivations</literal></term>
-
-    <listitem><para>If <literal>true</literal> (default), the garbage
-    collector will keep the derivations from which non-garbage store
-    paths were built.  If <literal>false</literal>, they will be
-    deleted unless explicitly registered as a root (or reachable from
-    other roots).</para>
-
-    <para>Keeping derivation around is useful for querying and
-    traceability (e.g., it allows you to ask with what dependencies or
-    options a store path was built), so by default this option is on.
-    Turn it off to save a bit of disk space (or a lot if
-    <literal>gc-keep-outputs</literal> is also turned on).</para></listitem>
-
-  </varlistentry>
-
-
-  <varlistentry><term><literal>env-keep-derivations</literal></term>
-
-    <listitem><para>If <literal>false</literal> (default), derivations
-    are not stored in Nix user environments.  That is, the derivation
-    any build-time-only dependencies may be garbage-collected.</para>
-
-    <para>If <literal>true</literal>, when you add a Nix derivation to
-    a user environment, the path of the derivation is stored in the
-    user environment.  Thus, the derivation will not be
-    garbage-collected until the user environment generation is deleted
-    (<command>nix-env --delete-generations</command>).  To prevent
-    build-time-only dependencies from being collected, you should also
-    turn on <literal>gc-keep-outputs</literal>.</para>
-
-    <para>The difference between this option and
-    <literal>gc-keep-derivations</literal> is that this one is
-    “sticky”: it applies to any user environment created while this
-    option was enabled, while <literal>gc-keep-derivations</literal>
-    only applies at the moment the garbage collector is
-    run.</para></listitem>
-
-  </varlistentry>
-
-
-  <varlistentry xml:id="conf-build-max-jobs"><term><literal>build-max-jobs</literal></term>
-
-    <listitem><para>This option defines the maximum number of jobs
-    that Nix will try to build in parallel.  The default is
-    <literal>1</literal>. The special value <literal>auto</literal>
-    causes Nix to use the number of CPUs in your system.  It can be
-    overridden using the <option
-    linkend='opt-max-jobs'>--max-jobs</option> (<option>-j</option>)
-    command line switch.</para></listitem>
-
-  </varlistentry>
-
-
-  <varlistentry xml:id="conf-build-cores"><term><literal>build-cores</literal></term>
-
-    <listitem><para>Sets the value of the
-    <envar>NIX_BUILD_CORES</envar> environment variable in the
-    invocation of builders.  Builders can use this variable at their
-    discretion to control the maximum amount of parallelism.  For
-    instance, in Nixpkgs, if the derivation attribute
-    <varname>enableParallelBuilding</varname> is set to
-    <literal>true</literal>, the builder passes the
-    <option>-j<replaceable>N</replaceable></option> flag to GNU Make.
-    It can be overridden using the <option
-    linkend='opt-cores'>--cores</option> command line switch and
-    defaults to <literal>1</literal>.  The value <literal>0</literal>
-    means that the builder should use all available CPU cores in the
-    system.</para></listitem>
-
-  </varlistentry>
-
-
-  <varlistentry xml:id="conf-build-max-silent-time"><term><literal>build-max-silent-time</literal></term>
+  <varlistentry xml:id="conf-allowed-uris"><term><literal>allowed-uris</literal></term>
 
     <listitem>
 
-      <para>This option defines the maximum number of seconds that a
-      builder can go without producing any data on standard output or
-      standard error.  This is useful (for instance in an automated
-      build system) to catch builds that are stuck in an infinite
-      loop, or to catch remote builds that are hanging due to network
-      problems.  It can be overridden using the <option
-      linkend="opt-max-silent-time">--max-silent-time</option> command
-      line switch.</para>
-
-      <para>The value <literal>0</literal> means that there is no
-      timeout.  This is also the default.</para>
+      <para>A list of URI prefixes to which access is allowed in
+      restricted evaluation mode. For example, when set to
+      <literal>https://github.com/NixOS</literal>, builtin functions
+      such as <function>fetchGit</function> are allowed to access
+      <literal>https://github.com/NixOS/patchelf.git</literal>.</para>
 
     </listitem>
 
   </varlistentry>
 
 
-  <varlistentry xml:id="conf-build-timeout"><term><literal>build-timeout</literal></term>
+  <varlistentry xml:id="conf-allow-import-from-derivation"><term><literal>allow-import-from-derivation</literal></term>
+
+    <listitem><para>By default, Nix allows you to <function>import</function> from a derivation,
+    allowing building at evaluation time. With this option set to false, Nix will throw an error
+    when evaluating an expression that uses this feature, allowing users to ensure their evaluation
+    will not require any builds to take place.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry xml:id="conf-allow-new-privileges"><term><literal>allow-new-privileges</literal></term>
+
+    <listitem><para>(Linux-specific.) By default, builders on Linux
+    cannot acquire new privileges by calling setuid/setgid programs or
+    programs that have file capabilities. For example, programs such
+    as <command>sudo</command> or <command>ping</command> will
+    fail. (Note that in sandbox builds, no such programs are available
+    unless you bind-mount them into the sandbox via the
+    <option>sandbox-paths</option> option.) You can allow the
+    use of such programs by enabling this option. This is impure and
+    usually undesirable, but may be useful in certain scenarios
+    (e.g. to spin up containers or set up userspace network interfaces
+    in tests).</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry xml:id="conf-allowed-users"><term><literal>allowed-users</literal></term>
 
     <listitem>
 
-      <para>This option defines the maximum number of seconds that a
-      builder can run.  This is useful (for instance in an automated
-      build system) to catch builds that are stuck in an infinite loop
-      but keep writing to their standard output or standard error.  It
-      can be overridden using the <option
-      linkend="opt-timeout">--timeout</option> command line
-      switch.</para>
+      <para>A list of names of users (separated by whitespace) that
+      are allowed to connect to the Nix daemon. As with the
+      <option>trusted-users</option> option, you can specify groups by
+      prefixing them with <literal>@</literal>. Also, you can allow
+      all users by specifying <literal>*</literal>. The default is
+      <literal>*</literal>.</para>
 
-      <para>The value <literal>0</literal> means that there is no
-      timeout.  This is also the default.</para>
+      <para>Note that trusted users are always allowed to connect.</para>
 
     </listitem>
 
   </varlistentry>
 
 
-  <varlistentry xml:id="conf-build-max-log-size"><term><literal>build-max-log-size</literal></term>
+  <varlistentry><term><literal>auto-optimise-store</literal></term>
 
+    <listitem><para>If set to <literal>true</literal>, Nix
+    automatically detects files in the store that have identical
+    contents, and replaces them with hard links to a single copy.
+    This saves disk space.  If set to <literal>false</literal> (the
+    default), you can still run <command>nix-store
+    --optimise</command> to get rid of duplicate
+    files.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry xml:id="conf-builders">
+    <term><literal>builders</literal></term>
     <listitem>
-
-      <para>This option defines the maximum number of bytes that a
-      builder can write to its stdout/stderr.  If the builder exceeds
-      this limit, it’s killed.  A value of <literal>0</literal> (the
-      default) means that there is no limit.</para>
-
+      <para>A list of machines on which to perform builds. <phrase
+      condition="manual">See <xref linkend="chap-distributed-builds"
+      /> for details.</phrase></para>
     </listitem>
+  </varlistentry>
+
+
+  <varlistentry><term><literal>builders-use-substitutes</literal></term>
+
+    <listitem><para>If set to <literal>true</literal>, Nix will instruct
+    remote build machines to use their own binary substitutes if available. In
+    practical terms, this means that remote hosts will fetch as many build
+    dependencies as possible from their own substitutes (e.g, from
+    <literal>cache.nixos.org</literal>), instead of waiting for this host to
+    upload them all. This can drastically reduce build times if the network
+    connection between this computer and the remote build host is slow. Defaults
+    to <literal>false</literal>.</para></listitem>
 
   </varlistentry>
 
@@ -245,106 +201,7 @@ false</literal>.</para>
   </varlistentry>
 
 
-  <varlistentry><term><literal>build-use-sandbox</literal></term>
-
-    <listitem><para>If set to <literal>true</literal>, builds will be
-    performed in a <emphasis>sandboxed environment</emphasis>, i.e.,
-    they’re isolated from the normal file system hierarchy and will
-    only see their dependencies in the Nix store, the temporary build
-    directory, private versions of <filename>/proc</filename>,
-    <filename>/dev</filename>, <filename>/dev/shm</filename> and
-    <filename>/dev/pts</filename> (on Linux), and the paths configured with the
-    <link linkend='conf-build-sandbox-paths'><literal>build-sandbox-paths</literal>
-    option</link>. This is useful to prevent undeclared dependencies
-    on files in directories such as <filename>/usr/bin</filename>. In
-    addition, on Linux, builds run in private PID, mount, network, IPC
-    and UTS namespaces to isolate them from other processes in the
-    system (except that fixed-output derivations do not run in private
-    network namespace to ensure they can access the network).</para>
-
-    <para>Currently, sandboxing only work on Linux and Mac OS X. The use
-    of a sandbox requires that Nix is run as root (so you should use
-    the <link linkend='conf-build-users-group'>“build users”
-    feature</link> to perform the actual builds under different users
-    than root).</para>
-
-    <para>If this option is set to <literal>relaxed</literal>, then
-    fixed-output derivations and derivations that have the
-    <varname>__noChroot</varname> attribute set to
-    <literal>true</literal> do not run in sandboxes.</para>
-
-    <para>The default is <literal>false</literal>.</para>
-
-    </listitem>
-
-  </varlistentry>
-
-
-  <varlistentry xml:id="conf-build-sandbox-paths">
-    <term><literal>build-sandbox-paths</literal></term>
-
-    <listitem><para>A list of paths bind-mounted into Nix sandbox
-    environments. You can use the syntax
-    <literal><replaceable>target</replaceable>=<replaceable>source</replaceable></literal>
-    to mount a path in a different location in the sandbox; for
-    instance, <literal>/bin=/nix-bin</literal> will mount the path
-    <literal>/nix-bin</literal> as <literal>/bin</literal> inside the
-    sandbox. If <replaceable>source</replaceable> is followed by
-    <literal>?</literal>, then it is not an error if
-    <replaceable>source</replaceable> does not exist; for example,
-    <literal>/dev/nvidiactl?</literal> specifies that
-    <filename>/dev/nvidiactl</filename> will only be mounted in the
-    sandbox if it exists in the host filesystem.</para>
-
-    <para>Depending on how Nix was built, the default value for this option
-    may be empty or provide <filename>/bin/sh</filename> as a
-    bind-mount of <command>bash</command>.</para></listitem>
-
-  </varlistentry>
-
-
-  <varlistentry xml:id="conf-build-extra-sandbox-paths">
-    <term><literal>build-extra-sandbox-paths</literal></term>
-
-    <listitem><para>A list of additional paths appended to
-    <option>build-sandbox-paths</option>. Useful if you want to extend
-    its default value.</para></listitem>
-
-  </varlistentry>
-
-
-  <varlistentry><term><literal>build-use-substitutes</literal></term>
-
-    <listitem><para>If set to <literal>true</literal> (default), Nix
-    will use binary substitutes if available.  This option can be
-    disabled to force building from source.</para></listitem>
-
-  </varlistentry>
-
-
-  <varlistentry><term><literal>build-fallback</literal></term>
-
-    <listitem><para>If set to <literal>true</literal>, Nix will fall
-    back to building from source if a binary substitute fails.  This
-    is equivalent to the <option>--fallback</option> flag.  The
-    default is <literal>false</literal>.</para></listitem>
-
-  </varlistentry>
-
-
-  <varlistentry><term><literal>build-keep-log</literal></term>
-
-    <listitem><para>If set to <literal>true</literal> (the default),
-    Nix will write the build log of a derivation (i.e. the standard
-    output and error of its builder) to the directory
-    <filename>/nix/var/log/nix/drvs</filename>.  The build log can be
-    retrieved using the command <command>nix-store -l
-    <replaceable>path</replaceable></command>.</para></listitem>
-
-  </varlistentry>
-
-
-  <varlistentry><term><literal>build-compress-log</literal></term>
+  <varlistentry><term><literal>compress-build-log</literal></term>
 
     <listitem><para>If set to <literal>true</literal> (the default),
     build logs written to <filename>/nix/var/log/nix/drvs</filename>
@@ -354,40 +211,45 @@ false</literal>.</para>
   </varlistentry>
 
 
-  <varlistentry><term><literal>substituters</literal></term>
+  <varlistentry xml:id="conf-connect-timeout"><term><literal>connect-timeout</literal></term>
 
-    <listitem><para>A list of URLs of substituters, separated by
-    whitespace.  The default is
-    <literal>https://cache.nixos.org</literal>.</para></listitem>
+    <listitem>
+
+      <para>The timeout (in seconds) for establishing connections in
+      the binary cache substituter.  It corresponds to
+      <command>curl</command>’s <option>--connect-timeout</option>
+      option.</para>
+
+    </listitem>
 
   </varlistentry>
 
 
-  <!--
-  <varlistentry><term><literal>binary-caches-files</literal></term>
+  <varlistentry xml:id="conf-cores"><term><literal>cores</literal></term>
 
-    <listitem><para>A list of names of files that will be read to
-    obtain additional binary cache URLs.  The default is
-    <literal>/nix/var/nix/profiles/per-user/<replaceable>username</replaceable>/channels/binary-caches/*</literal>.
-    Note that when you’re using the Nix daemon,
-    <replaceable>username</replaceable> is always equal to
-    <literal>root</literal>, so Nix will only use the binary caches
-    provided by the channels installed by root.  Do not set this
-    option to read files created by untrusted users!</para></listitem>
+    <listitem><para>Sets the value of the
+    <envar>NIX_BUILD_CORES</envar> environment variable in the
+    invocation of builders.  Builders can use this variable at their
+    discretion to control the maximum amount of parallelism.  For
+    instance, in Nixpkgs, if the derivation attribute
+    <varname>enableParallelBuilding</varname> is set to
+    <literal>true</literal>, the builder passes the
+    <option>-j<replaceable>N</replaceable></option> flag to GNU Make.
+    It can be overridden using the <option
+    linkend='opt-cores'>--cores</option> command line switch and
+    defaults to <literal>1</literal>.  The value <literal>0</literal>
+    means that the builder should use all available CPU cores in the
+    system.</para></listitem>
 
   </varlistentry>
-  -->
 
 
-  <varlistentry><term><literal>trusted-substituters</literal></term>
+  <varlistentry xml:id="conf-extra-sandbox-paths">
+    <term><literal>extra-sandbox-paths</literal></term>
 
-    <listitem><para>A list of URLs of substituters, separated by
-    whitespace.  These are not used by default, but can be enabled by
-    users of the Nix daemon by specifying <literal>--option
-    substituters <replaceable>urls</replaceable></literal> on the
-    command line.  Unprivileged users are only allowed to pass a
-    subset of the URLs listed in <literal>substituters</literal> and
-    <literal>trusted-substituters</literal>.</para></listitem>
+    <listitem><para>A list of additional paths appended to
+    <option>sandbox-paths</option>. Useful if you want to extend
+    its default value.</para></listitem>
 
   </varlistentry>
 
@@ -403,23 +265,51 @@ false</literal>.</para>
   </varlistentry>
 
 
-  <varlistentry><term><literal>signed-binary-caches</literal></term>
+  <varlistentry><term><literal>fallback</literal></term>
 
-    <listitem><para>If set to <literal>*</literal> (the default), Nix
-    will only download binaries if they are signed using one of the
-    keys listed in <option>binary-cache-public-keys</option>. Set to
-    the empty string to disable signature checking.</para></listitem>
+    <listitem><para>If set to <literal>true</literal>, Nix will fall
+    back to building from source if a binary substitute fails.  This
+    is equivalent to the <option>--fallback</option> flag.  The
+    default is <literal>false</literal>.</para></listitem>
 
   </varlistentry>
 
 
-  <varlistentry><term><literal>binary-cache-public-keys</literal></term>
+  <varlistentry><term><literal>fsync-metadata</literal></term>
 
-    <listitem><para>A whitespace-separated list of public keys
-    corresponding to the secret keys trusted to sign binary
-    caches. For example:
-    <literal>cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=
-    hydra.nixos.org-1:CNHJZBh9K4tP3EKF6FkkgeVYsS3ohTl+oS0Qa8bezVs=</literal>.</para></listitem>
+    <listitem><para>If set to <literal>true</literal>, changes to the
+    Nix store metadata (in <filename>/nix/var/nix/db</filename>) are
+    synchronously flushed to disk.  This improves robustness in case
+    of system crashes, but reduces performance.  The default is
+    <literal>true</literal>.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry xml:id="conf-hashed-mirrors"><term><literal>hashed-mirrors</literal></term>
+
+    <listitem><para>A list of web servers used by
+    <function>builtins.fetchurl</function> to obtain files by
+    hash. The default is
+    <literal>http://tarballs.nixos.org/</literal>. Given a hash type
+    <replaceable>ht</replaceable> and a base-16 hash
+    <replaceable>h</replaceable>, Nix will try to download the file
+    from
+    <literal>hashed-mirror/<replaceable>ht</replaceable>/<replaceable>h</replaceable></literal>.
+    This allows files to be downloaded even if they have disappeared
+    from their original URI. For example, given the default mirror
+    <literal>http://tarballs.nixos.org/</literal>, when building the derivation
+
+<programlisting>
+builtins.fetchurl {
+  url = https://example.org/foo-1.2.3.tar.xz;
+  sha256 = "2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae";
+}
+</programlisting>
+
+    Nix will attempt to download this file from
+    <literal>http://tarballs.nixos.org/sha256/2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae</literal>
+    first. If it is not available there, if will try the original URI.</para></listitem>
 
   </varlistentry>
 
@@ -433,6 +323,124 @@ false</literal>.</para>
   </varlistentry>
 
 
+  <varlistentry><term><literal>keep-build-log</literal></term>
+
+    <listitem><para>If set to <literal>true</literal> (the default),
+    Nix will write the build log of a derivation (i.e. the standard
+    output and error of its builder) to the directory
+    <filename>/nix/var/log/nix/drvs</filename>.  The build log can be
+    retrieved using the command <command>nix-store -l
+    <replaceable>path</replaceable></command>.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry xml:id="conf-keep-derivations"><term><literal>keep-derivations</literal></term>
+
+    <listitem><para>If <literal>true</literal> (default), the garbage
+    collector will keep the derivations from which non-garbage store
+    paths were built.  If <literal>false</literal>, they will be
+    deleted unless explicitly registered as a root (or reachable from
+    other roots).</para>
+
+    <para>Keeping derivation around is useful for querying and
+    traceability (e.g., it allows you to ask with what dependencies or
+    options a store path was built), so by default this option is on.
+    Turn it off to save a bit of disk space (or a lot if
+    <literal>keep-outputs</literal> is also turned on).</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry><term><literal>keep-env-derivations</literal></term>
+
+    <listitem><para>If <literal>false</literal> (default), derivations
+    are not stored in Nix user environments.  That is, the derivation
+    any build-time-only dependencies may be garbage-collected.</para>
+
+    <para>If <literal>true</literal>, when you add a Nix derivation to
+    a user environment, the path of the derivation is stored in the
+    user environment.  Thus, the derivation will not be
+    garbage-collected until the user environment generation is deleted
+    (<command>nix-env --delete-generations</command>).  To prevent
+    build-time-only dependencies from being collected, you should also
+    turn on <literal>keep-outputs</literal>.</para>
+
+    <para>The difference between this option and
+    <literal>keep-derivations</literal> is that this one is
+    “sticky”: it applies to any user environment created while this
+    option was enabled, while <literal>keep-derivations</literal>
+    only applies at the moment the garbage collector is
+    run.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry xml:id="conf-keep-outputs"><term><literal>keep-outputs</literal></term>
+
+    <listitem><para>If <literal>true</literal>, the garbage collector
+    will keep the outputs of non-garbage derivations.  If
+    <literal>false</literal> (default), outputs will be deleted unless
+    they are GC roots themselves (or reachable from other roots).</para>
+
+    <para>In general, outputs must be registered as roots separately.
+    However, even if the output of a derivation is registered as a
+    root, the collector will still delete store paths that are used
+    only at build time (e.g., the C compiler, or source tarballs
+    downloaded from the network).  To prevent it from doing so, set
+    this option to <literal>true</literal>.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry xml:id="conf-max-build-log-size"><term><literal>max-build-log-size</literal></term>
+
+    <listitem>
+
+      <para>This option defines the maximum number of bytes that a
+      builder can write to its stdout/stderr.  If the builder exceeds
+      this limit, it’s killed.  A value of <literal>0</literal> (the
+      default) means that there is no limit.</para>
+
+    </listitem>
+
+  </varlistentry>
+
+
+  <varlistentry xml:id="conf-max-jobs"><term><literal>max-jobs</literal></term>
+
+    <listitem><para>This option defines the maximum number of jobs
+    that Nix will try to build in parallel.  The default is
+    <literal>1</literal>. The special value <literal>auto</literal>
+    causes Nix to use the number of CPUs in your system.  It can be
+    overridden using the <option
+    linkend='opt-max-jobs'>--max-jobs</option> (<option>-j</option>)
+    command line switch.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry xml:id="conf-max-silent-time"><term><literal>max-silent-time</literal></term>
+
+    <listitem>
+
+      <para>This option defines the maximum number of seconds that a
+      builder can go without producing any data on standard output or
+      standard error.  This is useful (for instance in an automated
+      build system) to catch builds that are stuck in an infinite
+      loop, or to catch remote builds that are hanging due to network
+      problems.  It can be overridden using the <option
+      linkend="opt-max-silent-time">--max-silent-time</option> command
+      line switch.</para>
+
+      <para>The value <literal>0</literal> means that there is no
+      timeout.  This is also the default.</para>
+
+    </listitem>
+
+  </varlistentry>
+
+
   <varlistentry><term><literal>netrc-file</literal></term>
 
     <listitem><para>If set to an absolute path to a <filename>netrc</filename>
@@ -456,117 +464,33 @@ password <replaceable>my-password</replaceable>
   </varlistentry>
 
 
-  <varlistentry><term><literal>system</literal></term>
-
-    <listitem><para>This option specifies the canonical Nix system
-    name of the current installation, such as
-    <literal>i686-linux</literal> or
-    <literal>x86_64-darwin</literal>.  Nix can only build derivations
-    whose <literal>system</literal> attribute equals the value
-    specified here.  In general, it never makes sense to modify this
-    value from its default, since you can use it to ‘lie’ about the
-    platform you are building on (e.g., perform a Mac OS build on a
-    Linux machine; the result would obviously be wrong).  It only
-    makes sense if the Nix binaries can run on multiple platforms,
-    e.g., ‘universal binaries’ that run on <literal>x86_64-linux</literal> and
-    <literal>i686-linux</literal>.</para>
-
-    <para>It defaults to the canonical Nix system name detected by
-    <filename>configure</filename> at build time.</para></listitem>
-
-  </varlistentry>
-
-
-  <varlistentry><term><literal>fsync-metadata</literal></term>
-
-    <listitem><para>If set to <literal>true</literal>, changes to the
-    Nix store metadata (in <filename>/nix/var/nix/db</filename>) are
-    synchronously flushed to disk.  This improves robustness in case
-    of system crashes, but reduces performance.  The default is
-    <literal>true</literal>.</para></listitem>
-
-  </varlistentry>
-
-
-  <varlistentry><term><literal>auto-optimise-store</literal></term>
-
-    <listitem><para>If set to <literal>true</literal>, Nix
-    automatically detects files in the store that have identical
-    contents, and replaces them with hard links to a single copy.
-    This saves disk space.  If set to <literal>false</literal> (the
-    default), you can still run <command>nix-store
-    --optimise</command> to get rid of duplicate
-    files.</para></listitem>
-
-  </varlistentry>
-
-
-  <varlistentry xml:id="conf-connect-timeout"><term><literal>connect-timeout</literal></term>
-
+  <varlistentry xml:id="conf-plugin-files">
+    <term><literal>plugin-files</literal></term>
     <listitem>
-
-      <para>The timeout (in seconds) for establishing connections in
-      the binary cache substituter.  It corresponds to
-      <command>curl</command>’s <option>--connect-timeout</option>
-      option.</para>
-
-    </listitem>
-
-  </varlistentry>
-
-
-  <varlistentry xml:id="conf-trusted-users"><term><literal>trusted-users</literal></term>
-
-    <listitem>
-
-      <para>A list of names of users (separated by whitespace) that
-      have additional rights when connecting to the Nix daemon, such
-      as the ability to specify additional binary caches, or to import
-      unsigned NARs. You can also specify groups by prefixing them
-      with <literal>@</literal>; for instance,
-      <literal>@wheel</literal> means all users in the
-      <literal>wheel</literal> group. The default is
-      <literal>root</literal>.</para>
-
-      <warning><para>The users listed here have the ability to
-      compromise the security of a multi-user Nix store. For instance,
-      they could install Trojan horses subsequently executed by other
-      users. So you should consider carefully whether to add users to
-      this list.</para></warning>
-
-    </listitem>
-
-  </varlistentry>
-
-
-  <varlistentry xml:id="conf-allowed-users"><term><literal>allowed-users</literal></term>
-
-    <listitem>
-
-      <para>A list of names of users (separated by whitespace) that
-      are allowed to connect to the Nix daemon. As with the
-      <option>trusted-users</option> option, you can specify groups by
-      prefixing them with <literal>@</literal>. Also, you can allow
-      all users by specifying <literal>*</literal>. The default is
-      <literal>*</literal>.</para>
-
-      <para>Note that trusted users are always allowed to connect.</para>
-
-    </listitem>
-
-  </varlistentry>
-
-
-  <varlistentry xml:id="conf-restrict-eval"><term><literal>restrict-eval</literal></term>
-
-    <listitem>
-
-      <para>If set to <literal>true</literal>, the Nix evaluator will
-      not allow access to any files outside of the Nix search path (as
-      set via the <envar>NIX_PATH</envar> environment variable or the
-      <option>-I</option> option). The default is
-      <literal>false</literal>.</para>
-
+      <para>
+        A list of plugin files to be loaded by Nix. Each of these
+        files will be dlopened by Nix, allowing them to affect
+        execution through static initialization. In particular, these
+        plugins may construct static instances of RegisterPrimOp to
+        add new primops or constants to the expression language,
+        RegisterStoreImplementation to add new store implementations,
+        RegisterCommand to add new subcommands to the
+        <literal>nix</literal> command, and RegisterSetting to add new
+        nix config settings. See the constructors for those types for
+        more details.
+      </para>
+      <para>
+        Since these files are loaded into the same address space as
+        Nix itself, they must be DSOs compatible with the instance of
+        Nix running at the time (i.e. compiled against the same
+        headers, not linked to any incompatible libraries). They
+        should not be linked to any Nix libs directly, as those will
+        be available already at load time.
+      </para>
+      <para>
+        If an entry in the list is a directory, all files in the
+        directory are loaded as plugins (non-recursively).
+      </para>
     </listitem>
 
   </varlistentry>
@@ -597,7 +521,7 @@ password <replaceable>my-password</replaceable>
             <para>Pass a list of files and directories to be included in the
             sandbox for this build. One entry per line, terminated by an empty
             line. Entries have the same format as
-            <literal>build-sandbox-paths</literal>.</para>
+            <literal>sandbox-paths</literal>.</para>
 
           </listitem>
 
@@ -608,7 +532,7 @@ password <replaceable>my-password</replaceable>
   </varlistentry>
 
 
-  <varlistentry xml:id="conf-build-repeat"><term><literal>build-repeat</literal></term>
+  <varlistentry xml:id="conf-repeat"><term><literal>repeat</literal></term>
 
     <listitem><para>How many times to repeat builds to check whether
     they are deterministic. The default value is 0. If the value is
@@ -620,6 +544,70 @@ password <replaceable>my-password</replaceable>
   </varlistentry>
 
 
+  <varlistentry><term><literal>require-sigs</literal></term>
+
+    <listitem><para>If set to <literal>true</literal> (the default),
+    any non-content-addressed path added or copied to the Nix store
+    (e.g. when substituting from a binary cache) must have a valid
+    signature, that is, be signed using one of the keys listed in
+    <option>trusted-public-keys</option> or
+    <option>secret-key-files</option>. Set to <literal>false</literal>
+    to disable signature checking.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry xml:id="conf-restrict-eval"><term><literal>restrict-eval</literal></term>
+
+    <listitem>
+
+      <para>If set to <literal>true</literal>, the Nix evaluator will
+      not allow access to any files outside of the Nix search path (as
+      set via the <envar>NIX_PATH</envar> environment variable or the
+      <option>-I</option> option), or to URIs outside of
+      <option>allowed-uri</option>. The default is
+      <literal>false</literal>.</para>
+
+    </listitem>
+
+  </varlistentry>
+
+
+  <varlistentry><term><literal>sandbox</literal></term>
+
+    <listitem><para>If set to <literal>true</literal>, builds will be
+    performed in a <emphasis>sandboxed environment</emphasis>, i.e.,
+    they’re isolated from the normal file system hierarchy and will
+    only see their dependencies in the Nix store, the temporary build
+    directory, private versions of <filename>/proc</filename>,
+    <filename>/dev</filename>, <filename>/dev/shm</filename> and
+    <filename>/dev/pts</filename> (on Linux), and the paths configured with the
+    <link linkend='conf-sandbox-paths'><literal>sandbox-paths</literal>
+    option</link>. This is useful to prevent undeclared dependencies
+    on files in directories such as <filename>/usr/bin</filename>. In
+    addition, on Linux, builds run in private PID, mount, network, IPC
+    and UTS namespaces to isolate them from other processes in the
+    system (except that fixed-output derivations do not run in private
+    network namespace to ensure they can access the network).</para>
+
+    <para>Currently, sandboxing only work on Linux and macOS. The use
+    of a sandbox requires that Nix is run as root (so you should use
+    the <link linkend='conf-build-users-group'>“build users”
+    feature</link> to perform the actual builds under different users
+    than root).</para>
+
+    <para>If this option is set to <literal>relaxed</literal>, then
+    fixed-output derivations and derivations that have the
+    <varname>__noChroot</varname> attribute set to
+    <literal>true</literal> do not run in sandboxes.</para>
+
+    <para>The default is <literal>false</literal>.</para>
+
+    </listitem>
+
+  </varlistentry>
+
+
   <varlistentry xml:id="conf-sandbox-dev-shm-size"><term><literal>sandbox-dev-shm-size</literal></term>
 
     <listitem><para>This option determines the maximum size of the
@@ -633,12 +621,154 @@ password <replaceable>my-password</replaceable>
   </varlistentry>
 
 
-  <varlistentry xml:id="conf-allow-import-from-derivation"><term><literal>allow-import-from-derivation</literal></term>
+  <varlistentry xml:id="conf-sandbox-paths">
+    <term><literal>sandbox-paths</literal></term>
 
-    <listitem><para>By default, Nix allows you to <function>import</function> from a derivation,
-    allowing building at evaluation time. With this option set to false, Nix will throw an error
-    when evaluating an expression that uses this feature, allowing users to ensure their evaluation
-    will not require any builds to take place.</para></listitem>
+    <listitem><para>A list of paths bind-mounted into Nix sandbox
+    environments. You can use the syntax
+    <literal><replaceable>target</replaceable>=<replaceable>source</replaceable></literal>
+    to mount a path in a different location in the sandbox; for
+    instance, <literal>/bin=/nix-bin</literal> will mount the path
+    <literal>/nix-bin</literal> as <literal>/bin</literal> inside the
+    sandbox. If <replaceable>source</replaceable> is followed by
+    <literal>?</literal>, then it is not an error if
+    <replaceable>source</replaceable> does not exist; for example,
+    <literal>/dev/nvidiactl?</literal> specifies that
+    <filename>/dev/nvidiactl</filename> will only be mounted in the
+    sandbox if it exists in the host filesystem.</para>
+
+    <para>Depending on how Nix was built, the default value for this option
+    may be empty or provide <filename>/bin/sh</filename> as a
+    bind-mount of <command>bash</command>.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry><term><literal>secret-key-files</literal></term>
+
+    <listitem><para>A whitespace-separated list of files containing
+    secret (private) keys. These are used to sign locally-built
+    paths. They can be generated using <command>nix-store
+    --generate-binary-cache-key</command>. The corresponding public
+    key can be distributed to other users, who can add it to
+    <option>trusted-public-keys</option> in their
+    <filename>nix.conf</filename>.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry xml:id="conf-show-trace"><term><literal>show-trace</literal></term>
+
+    <listitem><para>Causes Nix to print out a stack trace in case of Nix
+    expression evaluation errors.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry><term><literal>substitute</literal></term>
+
+    <listitem><para>If set to <literal>true</literal> (default), Nix
+    will use binary substitutes if available.  This option can be
+    disabled to force building from source.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry><term><literal>substituters</literal></term>
+
+    <listitem><para>A list of URLs of substituters, separated by
+    whitespace.  The default is
+    <literal>https://cache.nixos.org</literal>.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry><term><literal>system</literal></term>
+
+    <listitem><para>This option specifies the canonical Nix system
+    name of the current installation, such as
+    <literal>i686-linux</literal> or
+    <literal>x86_64-darwin</literal>.  Nix can only build derivations
+    whose <literal>system</literal> attribute equals the value
+    specified here.  In general, it never makes sense to modify this
+    value from its default, since you can use it to ‘lie’ about the
+    platform you are building on (e.g., perform a Mac OS build on a
+    Linux machine; the result would obviously be wrong).  It only
+    makes sense if the Nix binaries can run on multiple platforms,
+    e.g., ‘universal binaries’ that run on <literal>x86_64-linux</literal> and
+    <literal>i686-linux</literal>.</para>
+
+    <para>It defaults to the canonical Nix system name detected by
+    <filename>configure</filename> at build time.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry xml:id="conf-timeout"><term><literal>timeout</literal></term>
+
+    <listitem>
+
+      <para>This option defines the maximum number of seconds that a
+      builder can run.  This is useful (for instance in an automated
+      build system) to catch builds that are stuck in an infinite loop
+      but keep writing to their standard output or standard error.  It
+      can be overridden using the <option
+      linkend="opt-timeout">--timeout</option> command line
+      switch.</para>
+
+      <para>The value <literal>0</literal> means that there is no
+      timeout.  This is also the default.</para>
+
+    </listitem>
+
+  </varlistentry>
+
+
+  <varlistentry><term><literal>trusted-public-keys</literal></term>
+
+    <listitem><para>A whitespace-separated list of public keys. When
+    paths are copied from another Nix store (such as a binary cache),
+    they must be signed with one of these keys. For example:
+    <literal>cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=
+    hydra.nixos.org-1:CNHJZBh9K4tP3EKF6FkkgeVYsS3ohTl+oS0Qa8bezVs=</literal>.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry><term><literal>trusted-substituters</literal></term>
+
+    <listitem><para>A list of URLs of substituters, separated by
+    whitespace.  These are not used by default, but can be enabled by
+    users of the Nix daemon by specifying <literal>--option
+    substituters <replaceable>urls</replaceable></literal> on the
+    command line.  Unprivileged users are only allowed to pass a
+    subset of the URLs listed in <literal>substituters</literal> and
+    <literal>trusted-substituters</literal>.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry xml:id="conf-trusted-users"><term><literal>trusted-users</literal></term>
+
+    <listitem>
+
+      <para>A list of names of users (separated by whitespace) that
+      have additional rights when connecting to the Nix daemon, such
+      as the ability to specify additional binary caches, or to import
+      unsigned NARs. You can also specify groups by prefixing them
+      with <literal>@</literal>; for instance,
+      <literal>@wheel</literal> means all users in the
+      <literal>wheel</literal> group. The default is
+      <literal>root</literal>.</para>
+
+      <warning><para>Adding a user to <option>trusted-users</option>
+      is essentially equivalent to giving that user root access to the
+      system. For example, the user can set
+      <option>sandbox-paths</option> and thereby obtain read access to
+      directories that are otherwise inacessible to
+      them.</para></warning>
+
+    </listitem>
 
   </varlistentry>
 

doc/manual/command-ref/env-common.xml

@@ -154,6 +154,8 @@ $ mount -o bind /mnt/otherdisk/nix /nix</screen>
   <literal>daemon</literal> if you want to use the Nix daemon to
   execute Nix operations. This is necessary in <link
   linkend="ssec-multi-user">multi-user Nix installations</link>.
+  If the Nix daemon's Unix socket is at some non-standard path,
+  this variable should be set to <literal>unix://path/to/socket</literal>.
   Otherwise, it should be left unset.</para></listitem>
 
 </varlistentry>

doc/manual/command-ref/nix-build.xml

@@ -29,8 +29,6 @@
       </group>
       <replaceable>attrPath</replaceable>
     </arg>
-    <arg><option>--drv-link</option> <replaceable>drvlink</replaceable></arg>
-    <arg><option>--add-drv-link</option></arg>
     <arg><option>--no-out-link</option></arg>
     <arg>
       <group choice='req'>
@@ -91,25 +89,6 @@ also <xref linkend="sec-common-options" />.</phrase></para>
 
 <variablelist>
 
-  <varlistentry><term><option>--drv-link</option> <replaceable>drvlink</replaceable></term>
-
-    <listitem><para>Add a symlink named
-    <replaceable>drvlink</replaceable> to the store derivation
-    produced by <command>nix-instantiate</command>.  The derivation is
-    a root of the garbage collector until the symlink is deleted or
-    renamed.  If there are multiple derivations, numbers are suffixed
-    to <replaceable>drvlink</replaceable> to distinguish between
-    them.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><option>--add-drv-link</option></term>
-
-    <listitem><para>Shorthand for <option>--drv-link</option>
-    <filename>./derivation</filename>.</para></listitem>
-
-  </varlistentry>
-
   <varlistentry><term><option>--no-out-link</option></term>
 
     <listitem><para>Do not create a symlink to the output path.  Note

doc/manual/command-ref/nix-channel.xml

@@ -31,7 +31,7 @@
 
 <refsection><title>Description</title>
 
-<para>A Nix channel is mechanism that allows you to automatically stay
+<para>A Nix channel is a mechanism that allows you to automatically stay
 up-to-date with a set of pre-built Nix expressions.  A Nix channel is
 just a URL that points to a place containing both a set of Nix
 expressions and a pointer to a binary cache.  <phrase
@@ -165,8 +165,8 @@ following files:</para>
   <varlistentry><term><filename>nixexprs.tar.xz</filename></term>
 
     <listitem><para>A tarball containing Nix expressions and files
-    referenced by them (such as build scripts and patches). At
-    top-level, the tarball should contain a single directory. That
+    referenced by them (such as build scripts and patches). At the
+    top level, the tarball should contain a single directory. That
     directory must contain a file <filename>default.nix</filename>
     that serves as the channel’s “entry point”.</para></listitem>
 
@@ -175,7 +175,7 @@ following files:</para>
   <varlistentry><term><filename>binary-cache-url</filename></term>
 
     <listitem><para>A file containing the URL to a binary cache (such
-    as <uri>https://cache.nixos.org</uri>. Nix will automatically
+    as <uri>https://cache.nixos.org</uri>). Nix will automatically
     check this cache for pre-built binaries, if the user has
     sufficient rights to add binary caches. For instance, in a
     multi-user Nix setup, the binary caches provided by the channels

doc/manual/command-ref/nix-copy-closure.xml

@@ -27,8 +27,10 @@
     <arg><option>- -show-progress</option></arg>
     -->
     <arg><option>--include-outputs</option></arg>
-    <arg><option>--use-substitutes</option></arg>
-    <arg><option>-s</option></arg>
+    <group>
+      <arg choice='plain'><option>--use-substitutes</option></arg>
+      <arg choice='plain'><option>-s</option></arg>
+    </group>
     <arg><option>-v</option></arg>
     <arg choice='plain'>
       <replaceable>user@</replaceable><replaceable>machine</replaceable>

doc/manual/command-ref/nix-env.xml

@@ -146,8 +146,7 @@ also <xref linkend="sec-common-options" />.</phrase></para>
 
 <variablelist>
 
-  <varlistentry><term><option>--file</option></term>
-    <term><option>-f</option></term>
+  <varlistentry><term><option>--file</option> / <option>-f</option> <replaceable>path</replaceable></term>
 
     <listitem><para>Specifies the Nix expression (designated below as
     the <emphasis>active Nix expression</emphasis>) used by the
@@ -166,8 +165,7 @@ also <xref linkend="sec-common-options" />.</phrase></para>
 
   </varlistentry>
 
-  <varlistentry><term><option>--profile</option></term>
-    <term><option>-p</option></term>
+  <varlistentry><term><option>--profile</option> / <option>-p</option> <replaceable>path</replaceable></term>
 
     <listitem><para>Specifies the profile to be used by those
     operations that operate on a profile (designated below as the

doc/manual/command-ref/nix-hash.xml

@@ -44,7 +44,9 @@
 cryptographic hash of the contents of each
 <replaceable>path</replaceable> and prints it on standard output.  By
 default, it computes an MD5 hash, but other hash algorithms are
-available as well.  The hash is printed in hexadecimal.</para>
+available as well.  The hash is printed in hexadecimal.  To generate
+the same hash as <command>nix-prefetch-url</command> you have to
+specify multiple arguments, see below for an example.</para>
 
 <para>The hash is computed over a <emphasis>serialisation</emphasis>
 of each path: a dump of the file system tree rooted at the path.  This
@@ -122,6 +124,15 @@ cryptographic hash as <literal>nix-store --dump
 
 <refsection><title>Examples</title>
 
+<para>Computing the same hash as <command>nix-prefetch-url</command>:
+<screen>
+$ nix-prefetch-url file://&lt;(echo test)
+1lkgqb6fclns49861dwk9rzb6xnfkxbpws74mxnx01z9qyv1pjpj
+$ nix-hash --type sha256 --flat --base32 &lt;(echo test)
+1lkgqb6fclns49861dwk9rzb6xnfkxbpws74mxnx01z9qyv1pjpj
+</screen>
+</para>
+
 <para>Computing hashes:
 
 <screen>

doc/manual/command-ref/nix-instantiate.xml

@@ -24,6 +24,7 @@
       <arg choice='plain'>
         <option>--eval</option>
         <arg><option>--strict</option></arg>
+        <arg><option>--json</option></arg>
         <arg><option>--xml</option></arg>
       </arg>
     </group>
@@ -38,12 +39,13 @@
     </arg>
     <arg><option>--add-root</option> <replaceable>path</replaceable></arg>
     <arg><option>--indirect</option></arg>
-    <group choice='req'>
+    <group>
       <arg choice='plain'><option>--expr</option></arg>
       <arg choice='plain'><option>-E</option></arg>
     </group>
     <arg choice='plain' rep='repeat'><replaceable>files</replaceable></arg>
-    <sbr/>
+  </cmdsynopsis>
+  <cmdsynopsis>
     <command>nix-instantiate</command>
     <arg choice='plain'><option>--find-file</option></arg>
     <arg choice='plain' rep='repeat'><replaceable>files</replaceable></arg>
@@ -115,24 +117,6 @@ input.</para>
 
   </varlistentry>
 
-  <varlistentry><term><option>--xml</option></term>
-
-    <listitem><para>When used with <option>--eval</option>, print the resulting
-    value as an XML representation of the abstract syntax tree rather than as
-    an ATerm. The schema is the same as that used by the <link
-    linkend="builtin-toXML"><function>toXML</function> built-in</link>.
-    </para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><option>--json</option></term>
-
-    <listitem><para>When used with <option>--eval</option>, print the resulting
-    value as an JSON representation of the abstract syntax tree rather
-    than as an ATerm.</para></listitem>
-
-  </varlistentry>
-
   <varlistentry><term><option>--strict</option></term>
 
     <listitem><para>When used with <option>--eval</option>,
@@ -147,6 +131,24 @@ input.</para>
 
   </varlistentry>
 
+  <varlistentry><term><option>--json</option></term>
+
+    <listitem><para>When used with <option>--eval</option>, print the resulting
+    value as an JSON representation of the abstract syntax tree rather
+    than as an ATerm.</para></listitem>
+
+  </varlistentry>
+
+  <varlistentry><term><option>--xml</option></term>
+
+    <listitem><para>When used with <option>--eval</option>, print the resulting
+    value as an XML representation of the abstract syntax tree rather than as
+    an ATerm. The schema is the same as that used by the <link
+    linkend="builtin-toXML"><function>toXML</function> built-in</link>.
+    </para></listitem>
+
+  </varlistentry>
+
   <varlistentry><term><option>--read-write-mode</option></term>
 
     <listitem><para>When used with <option>--eval</option>, perform

doc/manual/command-ref/nix-prefetch-url.xml

@@ -19,14 +19,16 @@
 <refsynopsisdiv>
   <cmdsynopsis>
     <command>nix-prefetch-url</command>
+    <arg><option>--version</option></arg>
     <arg><option>--type</option> <replaceable>hashAlgo</replaceable></arg>
     <arg><option>--print-path</option></arg>
+    <arg><option>--unpack</option></arg>
+    <arg><option>--name</option> <replaceable>name</replaceable></arg>
     <arg choice='plain'><replaceable>url</replaceable></arg>
     <arg><replaceable>hash</replaceable></arg>
   </cmdsynopsis>
 </refsynopsisdiv>
 
-
 <refsection><title>Description</title>
 
 <para>The command <command>nix-prefetch-url</command> downloads the
@@ -91,7 +93,7 @@ downloaded file in the Nix store is also printed.</para>
 
   </varlistentry>
 
-  <varlistentry><term><option>--name</option></term>
+  <varlistentry><term><option>--name</option> <replaceable>name</replaceable></term>
 
     <listitem><para>Override the name of the file in the Nix store. By
     default, this is

doc/manual/command-ref/nix-shell.xml

@@ -33,13 +33,13 @@
     <arg><option>--exclude</option> <replaceable>regexp</replaceable></arg>
     <arg><option>--pure</option></arg>
     <group choice='req'>
-      <group choice='plain'>
-        <group>
+      <arg choice='plain'>
+        <group choice='req'>
           <arg choice='plain'><option>--packages</option></arg>
           <arg choice='plain'><option>-p</option></arg>
         </group>
-        <replaceable>packages</replaceable>
-      </group>
+        <arg choice='plain' rep='repeat'><replaceable>packages</replaceable></arg>
+      </arg>
       <arg><replaceable>path</replaceable></arg>
     </group>
   </cmdsynopsis>
@@ -144,7 +144,7 @@ also <xref linkend="sec-common-options" />.</phrase></para>
 
   </varlistentry>
 
-  <varlistentry><term><option>--packages</option> / <option>-p</option></term>
+  <varlistentry><term><option>--packages</option> / <option>-p</option> <replaceable>packages</replaceable>…</term>
 
     <listitem><para>Set up an environment in which the specified
     packages are present.  The command line arguments are interpreted

doc/manual/command-ref/nix-store.xml

@@ -234,7 +234,7 @@ linkend="sec-nix-build"><command>nix-build</command></link> does.</para>
 <para>To test whether a previously-built derivation is deterministic:
 
 <screen>
-$ nix-build -r '&lt;nixpkgs>' -A hello --check -K
+$ nix-build '&lt;nixpkgs>' -A hello --check -K
 </screen>
 
 </para>
@@ -397,9 +397,9 @@ options control what gets deleted and in what order:
 </para>
 
 <para>The behaviour of the collector is also influenced by the <link
-linkend="conf-gc-keep-outputs"><literal>gc-keep-outputs</literal></link>
+linkend="conf-keep-outputs"><literal>keep-outputs</literal></link>
 and <link
-linkend="conf-gc-keep-derivations"><literal>gc-keep-derivations</literal></link>
+linkend="conf-keep-derivations"><literal>keep-derivations</literal></link>
 variables in the Nix configuration file.</para>
 
 <para>With <option>--delete</option>, the collector prints the total
@@ -501,10 +501,11 @@ error: cannot delete path `/nix/store/zq0h41l75vlb4z45kzgjjmsjxvcv1qk7-mesa-6.4'
     <arg choice='plain'><option>--referrers</option></arg>
     <arg choice='plain'><option>--referrers-closure</option></arg>
     <arg choice='plain'><option>--deriver</option></arg>
-    <arg choice='plain'><option>--deriver</option></arg>
+    <arg choice='plain'><option>-d</option></arg>
     <arg choice='plain'><option>--graph</option></arg>
     <arg choice='plain'><option>--tree</option></arg>
     <arg choice='plain'><option>--binding</option> <replaceable>name</replaceable></arg>
+    <arg choice='plain'><option>-b</option> <replaceable>name</replaceable></arg>
     <arg choice='plain'><option>--hash</option></arg>
     <arg choice='plain'><option>--size</option></arg>
     <arg choice='plain'><option>--roots</option></arg>
@@ -642,6 +643,7 @@ query is applied to the target of the symlink.</para>
   </varlistentry>
 
   <varlistentry><term><option>--deriver</option></term>
+    <term><option>-d</option></term>
 
     <listitem><para>Prints the <link
     linkend="gloss-deriver">deriver</link> of the store paths
@@ -678,6 +680,7 @@ query is applied to the target of the symlink.</para>
   </varlistentry>
 
   <varlistentry><term><option>--binding</option> <replaceable>name</replaceable></term>
+    <term><option>-b</option> <replaceable>name</replaceable></term>
 
     <listitem><para>Prints the value of the attribute
     <replaceable>name</replaceable> (i.e., environment variable) of

doc/manual/command-ref/opt-common-syn.xml

@@ -2,10 +2,18 @@
   
 <arg><option>--help</option></arg>
 <arg><option>--version</option></arg>
-<arg rep='repeat'><option>--verbose</option></arg>
-<arg rep='repeat'><option>-v</option></arg>
-<arg><option>--no-build-output</option></arg>
-<arg><option>-Q</option></arg>
+<arg rep='repeat'>
+  <group choice='req'>
+    <arg choice='plain'><option>--verbose</option></arg>
+    <arg choice='plain'><option>-v</option></arg>
+  </group>
+</arg>
+<arg>
+  <group choice='plain'>
+    <arg choice='plain'><option>--no-build-output</option></arg>
+    <arg choice='plain'><option>-Q</option></arg>
+  </group>
+</arg>
 <arg>
   <group choice='req'>
     <arg choice='plain'><option>--max-jobs</option></arg>
@@ -25,13 +33,20 @@
   <option>--timeout</option>
   <replaceable>number</replaceable>
 </arg>
-<arg><option>--keep-going</option></arg>
-<arg><option>-k</option></arg>
-<arg><option>--keep-failed</option></arg>
-<arg><option>-K</option></arg>
+<arg>
+  <group choice='plain'>
+    <arg choice='plain'><option>--keep-going</option></arg>
+    <arg choice='plain'><option>-k</option></arg>
+  </group>
+</arg>
+<arg>
+  <group choice='plain'>
+    <arg choice='plain'><option>--keep-failed</option></arg>
+    <arg choice='plain'><option>-K</option></arg>
+  </group>
+</arg>
 <arg><option>--fallback</option></arg>
 <arg><option>--readonly-mode</option></arg>
-<arg><option>--show-trace</option></arg>
 <arg>
   <option>-I</option>
   <replaceable>path</replaceable>

doc/manual/command-ref/opt-common.xml

@@ -22,8 +22,7 @@
 </varlistentry>
 
 
-<varlistentry><term><option>--verbose</option></term>
-  <term><option>-v</option></term>
+<varlistentry><term><option>--verbose</option> / <option>-v</option></term>
 
   <listitem>
 
@@ -76,8 +75,7 @@
 </varlistentry>
 
 
-<varlistentry><term><option>--no-build-output</option></term>
-  <term><option>-Q</option></term>
+<varlistentry><term><option>--no-build-output</option> / <option>-Q</option></term>
 
   <listitem><para>By default, output written by builders to standard
   output and standard error is echoed to the Nix command's standard
@@ -89,14 +87,14 @@
 </varlistentry>
 
 
-<varlistentry xml:id="opt-max-jobs"><term><option>--max-jobs</option></term>
-  <term><option>-j</option></term>
+<varlistentry xml:id="opt-max-jobs"><term><option>--max-jobs</option> / <option>-j</option>
+<replaceable>number</replaceable></term>
 
   <listitem><para>Sets the maximum number of build jobs that Nix will
   perform in parallel to the specified number.  Specify
   <literal>auto</literal> to use the number of CPUs in the system.
   The default is specified by the <link
-  linkend='conf-build-max-jobs'><literal>build-max-jobs</literal></link>
+  linkend='conf-max-jobs'><literal>max-jobs</literal></link>
   configuration setting, which itself defaults to
   <literal>1</literal>.  A higher value is useful on SMP systems or to
   exploit I/O latency.</para></listitem>
@@ -114,7 +112,7 @@
   <literal>true</literal>, the builder passes the
   <option>-j<replaceable>N</replaceable></option> flag to GNU Make.
   It defaults to the value of the <link
-  linkend='conf-build-cores'><literal>build-cores</literal></link>
+  linkend='conf-cores'><literal>cores</literal></link>
   configuration setting, if set, or <literal>1</literal> otherwise.
   The value <literal>0</literal> means that the builder should use all
   available CPU cores in the system.</para></listitem>
@@ -127,7 +125,7 @@
   <listitem><para>Sets the maximum number of seconds that a builder
   can go without producing any data on standard output or standard
   error.  The default is specified by the <link
-  linkend='conf-build-max-silent-time'><literal>build-max-silent-time</literal></link>
+  linkend='conf-max-silent-time'><literal>max-silent-time</literal></link>
   configuration setting.  <literal>0</literal> means no
   time-out.</para></listitem>
 
@@ -137,14 +135,13 @@
 
   <listitem><para>Sets the maximum number of seconds that a builder
   can run.  The default is specified by the <link
-  linkend='conf-build-timeout'><literal>build-timeout</literal></link>
+  linkend='conf-timeout'><literal>timeout</literal></link>
   configuration setting.  <literal>0</literal> means no
   timeout.</para></listitem>
 
 </varlistentry>
 
-<varlistentry><term><option>--keep-going</option></term>
-  <term><option>-k</option></term>
+<varlistentry><term><option>--keep-going</option> / <option>-k</option></term>
 
   <listitem><para>Keep going in case of failed builds, to the
   greatest extent possible.  That is, if building an input of some
@@ -156,8 +153,7 @@
 </varlistentry>
 
 
-<varlistentry><term><option>--keep-failed</option></term>
-  <term><option>-K</option></term>
+<varlistentry><term><option>--keep-failed</option> / <option>-K</option></term>
 
   <listitem><para>Specifies that in case of a build failure, the
   temporary directory (usually in <filename>/tmp</filename>) in which
@@ -305,13 +301,6 @@
 
 </varlistentry>
 
-<varlistentry><term><option>--show-trace</option></term>
-
-  <listitem><para>Causes Nix to print out a stack trace in case of Nix
-  expression evaluation errors.</para></listitem>
-
-</varlistentry>
-
 
 <varlistentry xml:id="opt-I"><term><option>-I</option> <replaceable>path</replaceable></term>
 

doc/manual/expressions/advanced-attributes.xml

@@ -139,7 +139,7 @@ impureEnvVars = [ "http_proxy" "https_proxy" <replaceable>...</replaceable> ];
 <programlisting>
 fetchurl {
   url = http://ftp.gnu.org/pub/gnu/hello/hello-2.1.1.tar.gz;
-  md5 = "70c9ccf9fac07f762c24f2df2290784d";
+  sha256 = "1md7jsfd8pa45z73bz1kszpp01yw6x5ljkjk2hx7wl800any6465";
 }
 </programlisting>
 
@@ -150,7 +150,7 @@ fetchurl {
 <programlisting>
 fetchurl {
   url = ftp://ftp.nluug.nl/pub/gnu/hello/hello-2.1.1.tar.gz;
-  md5 = "70c9ccf9fac07f762c24f2df2290784d";
+  sha256 = "1md7jsfd8pa45z73bz1kszpp01yw6x5ljkjk2hx7wl800any6465";
 }
 </programlisting>
 

doc/manual/expressions/builtins.xml

@@ -126,6 +126,17 @@ if builtins ? getEnv then builtins.getEnv "PATH" else ""</programlisting>
   </varlistentry>
 
 
+  <varlistentry><term><function>builtins.splitVersion</function>
+  <replaceable>s</replaceable></term>
+
+    <listitem><para>Split a string representing a version into its
+    components, by the same version splitting logic underlying the
+    version comparison in <link linkend="ssec-version-comparisons">
+    <command>nix-env -u</command></link>.</para></listitem>
+
+  </varlistentry>
+
+
   <varlistentry><term><function>builtins.concatLists</function>
   <replaceable>lists</replaceable></term>
 
@@ -134,6 +145,14 @@ if builtins ? getEnv then builtins.getEnv "PATH" else ""</programlisting>
 
   </varlistentry>
 
+  <varlistentry><term><function>builtins.concatStringsSep</function>
+  <replaceable>separator</replaceable> <replaceable>list</replaceable></term>
+
+    <listitem><para>Concatenate a list of strings with a separator
+    between each element, e.g. <literal>concatStringsSep "/"
+    ["usr" "local" "bin"] == "usr/local/bin"</literal></para></listitem>
+
+  </varlistentry>
 
   <varlistentry
   xml:id='builtin-currentSystem'><term><varname>builtins.currentSystem</varname></term>
@@ -210,42 +229,6 @@ if builtins ? getEnv then builtins.getEnv "PATH" else ""</programlisting>
 
   </varlistentry>
 
-  <varlistentry><term><function>builtins.match</function>
-  <replaceable>regex</replaceable> <replaceable>str</replaceable></term>
-
-  <listitem><para>Returns a list if the <link
-  xlink:href="http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap09.html#tag_09_04">extended
-  POSIX regular expression</link> <replaceable>regex</replaceable>
-  matches <replaceable>str</replaceable> precisely, otherwise returns
-  <literal>null</literal>.  Each item in the list is a regex group.
-
-<programlisting>
-builtins.match "ab" "abc"
-</programlisting>
-
-Evaluates to <literal>null</literal>.
-
-<programlisting>
-builtins.match "abc" "abc"
-</programlisting>
-
-Evaluates to <literal>[ ]</literal>.
-
-<programlisting>
-builtins.match "a(b)(c)" "abc"
-</programlisting>
-
-Evaluates to <literal>[ "b" "c" ]</literal>.
-
-<programlisting>
-builtins.match "[[:space:]]+([[:upper:]]+)[[:space:]]+" "  FOO   "
-</programlisting>
-
-Evaluates to <literal>[ "foo" ]</literal>.
-
-  </para></listitem>
-  </varlistentry>
-
   <varlistentry><term><function>builtins.elem</function>
   <replaceable>x</replaceable> <replaceable>xs</replaceable></term>
 
@@ -300,13 +283,13 @@ stdenv.mkDerivation { … }
 
     Note that when obtaining the hash with <varname>nix-prefetch-url
     </varname> the option <varname>--unpack</varname> is required.
-    </para> 
-      
-    <para>This function can also verify the contents against a hash. 
-    In that case, the function takes a set instead of a URL. The set 
+    </para>
+
+    <para>This function can also verify the contents against a hash.
+    In that case, the function takes a set instead of a URL. The set
     requires the attribute <varname>url</varname> and the attribute
     <varname>sha256</varname>, e.g.
-      
+
 <programlisting>
 with import (fetchTarball {
   url = https://github.com/NixOS/nixpkgs-channels/archive/nixos-14.12.tar.gz;
@@ -315,7 +298,7 @@ with import (fetchTarball {
 
 stdenv.mkDerivation { … }
 </programlisting>
-      
+
     </para>
 
     <para>This function is not available if <link
@@ -324,6 +307,61 @@ stdenv.mkDerivation { … }
 
   </varlistentry>
 
+  <varlistentry>
+    <term>
+      <function>builtins.fetchGit</function>
+      <replaceable>args</replaceable>
+    </term>
+
+    <listitem>
+      <para>
+        Fetch a path from git. <replaceable>args</replaceable> can be
+        a URL, in which case the HEAD of the repo at that URL is
+        fetched. Otherwise, it can be an attribute with the following
+        attributes (all except <varname>url</varname> optional):
+      </para>
+
+      <variablelist>
+        <varlistentry>
+          <term>url</term>
+          <listitem>
+            <para>
+              The URL of the repo.
+            </para>
+          </listitem>
+        </varlistentry>
+        <varlistentry>
+          <term>name</term>
+          <listitem>
+            <para>
+              The name of the directory the repo should be exported to
+              in the store. Defaults to the basename of the URL.
+            </para>
+          </listitem>
+        </varlistentry>
+        <varlistentry>
+          <term>rev</term>
+          <listitem>
+            <para>
+              The git revision to fetch. Defaults to the tip of
+              <varname>ref</varname>.
+            </para>
+          </listitem>
+        </varlistentry>
+        <varlistentry>
+          <term>ref</term>
+          <listitem>
+            <para>
+              The git ref to look for the requested revision under.
+              This is often a branch or tag name. Defaults to
+              <literal>HEAD</literal>.
+            </para>
+          </listitem>
+        </varlistentry>
+      </variablelist>
+    </listitem>
+  </varlistentry>
+
 
   <varlistentry><term><function>builtins.filter</function>
   <replaceable>f</replaceable> <replaceable>xs</replaceable></term>
@@ -336,8 +374,9 @@ stdenv.mkDerivation { … }
   </varlistentry>
 
 
-  <varlistentry><term><function>builtins.filterSource</function>
-  <replaceable>e1</replaceable> <replaceable>e2</replaceable></term>
+  <varlistentry xml:id='builtin-filterSource'>
+    <term><function>builtins.filterSource</function>
+    <replaceable>e1</replaceable> <replaceable>e2</replaceable></term>
 
     <listitem>
 
@@ -636,6 +675,16 @@ x: x + 456</programlisting>
   </varlistentry>
 
 
+  <varlistentry><term><function>builtins.isFloat</function>
+  <replaceable>e</replaceable></term>
+
+    <listitem><para>Return <literal>true</literal> if
+    <replaceable>e</replaceable> evaluates to a float, and
+    <literal>false</literal> otherwise.</para></listitem>
+
+  </varlistentry>
+
+
   <varlistentry><term><function>builtins.isBool</function>
   <replaceable>e</replaceable></term>
 
@@ -726,6 +775,42 @@ map (x: "foo" + x) [ "bar" "bla" "abc" ]</programlisting>
   </varlistentry>
 
 
+  <varlistentry><term><function>builtins.match</function>
+  <replaceable>regex</replaceable> <replaceable>str</replaceable></term>
+
+  <listitem><para>Returns a list if the <link
+  xlink:href="http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap09.html#tag_09_04">extended
+  POSIX regular expression</link> <replaceable>regex</replaceable>
+  matches <replaceable>str</replaceable> precisely, otherwise returns
+  <literal>null</literal>.  Each item in the list is a regex group.
+
+<programlisting>
+builtins.match "ab" "abc"
+</programlisting>
+
+Evaluates to <literal>null</literal>.
+
+<programlisting>
+builtins.match "abc" "abc"
+</programlisting>
+
+Evaluates to <literal>[ ]</literal>.
+
+<programlisting>
+builtins.match "a(b)(c)" "abc"
+</programlisting>
+
+Evaluates to <literal>[ "b" "c" ]</literal>.
+
+<programlisting>
+builtins.match "[[:space:]]+([[:upper:]]+)[[:space:]]+" "  FOO   "
+</programlisting>
+
+Evaluates to <literal>[ "foo" ]</literal>.
+
+  </para></listitem>
+  </varlistentry>
+
   <varlistentry><term><function>builtins.mul</function>
   <replaceable>e1</replaceable> <replaceable>e2</replaceable></term>
 
@@ -750,6 +835,75 @@ map (x: "foo" + x) [ "bar" "bla" "abc" ]</programlisting>
 
   </varlistentry>
 
+  <varlistentry>
+    <term>
+      <function>builtins.path</function>
+      <replaceable>args</replaceable>
+    </term>
+
+    <listitem>
+      <para>
+        An enrichment of the built-in path type, based on the attributes
+        present in <replaceable>args</replaceable>. All are optional
+        except <varname>path</varname>:
+      </para>
+
+      <variablelist>
+        <varlistentry>
+          <term>path</term>
+          <listitem>
+            <para>The underlying path.</para>
+          </listitem>
+        </varlistentry>
+        <varlistentry>
+          <term>name</term>
+          <listitem>
+            <para>
+              The name of the path when added to the store. This can
+              used to reference paths that have nix-illegal characters
+              in their names, like <literal>@</literal>.
+            </para>
+          </listitem>
+        </varlistentry>
+        <varlistentry>
+          <term>filter</term>
+          <listitem>
+            <para>
+              A function of the type expected by
+              <link linkend="builtin-filterSource">builtins.filterSource</link>,
+              with the same semantics.
+            </para>
+          </listitem>
+        </varlistentry>
+        <varlistentry>
+          <term>recursive</term>
+          <listitem>
+            <para>
+              When <literal>false</literal>, when
+              <varname>path</varname> is added to the store it is with a
+              flat hash, rather than a hash of the NAR serialization of
+              the file. Thus, <varname>path</varname> must refer to a
+              regular file, not a directory. This allows similar
+              behavior to <literal>fetchurl</literal>. Defaults to
+              <literal>true</literal>.
+            </para>
+          </listitem>
+        </varlistentry>
+        <varlistentry>
+          <term>sha256</term>
+          <listitem>
+            <para>
+              When provided, this is the expected hash of the file at
+              the path. Evaluation will fail if the hash is incorrect,
+              and providing a hash allows
+              <literal>builtins.path</literal> to be used even when the
+              <literal>pure-eval</literal> nix config option is on.
+            </para>
+          </listitem>
+        </varlistentry>
+      </variablelist>
+    </listitem>
+  </varlistentry>
 
   <varlistentry><term><function>builtins.pathExists</function>
   <replaceable>path</replaceable></term>
@@ -873,6 +1027,43 @@ builtins.sort builtins.lessThan [ 483 249 526 147 42 77 ]
   </varlistentry>
 
 
+  <varlistentry><term><function>builtins.split</function>
+  <replaceable>regex</replaceable> <replaceable>str</replaceable></term>
+
+  <listitem><para>Returns a list composed of non matched strings interleaved
+  with the lists of the <link
+  xlink:href="http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap09.html#tag_09_04">extended
+  POSIX regular expression</link> <replaceable>regex</replaceable> matches
+  of <replaceable>str</replaceable>. Each item in the lists of matched
+  sequences is a regex group.
+
+<programlisting>
+builtins.split "(a)b" "abc"
+</programlisting>
+
+Evaluates to <literal>[ "" [ "a" ] "c" ]</literal>.
+
+<programlisting>
+builtins.split "([ac])" "abc"
+</programlisting>
+
+Evaluates to <literal>[ "" [ "a" ] "b" [ "c" ] "" ]</literal>.
+
+<programlisting>
+builtins.split "(a)|(c)" "abc"
+</programlisting>
+
+Evaluates to <literal>[ "" [ "a" null ] "b" [ null "c" ] "" ]</literal>.
+
+<programlisting>
+builtins.split "([[:upper:]]+)" "  FOO   "
+</programlisting>
+
+Evaluates to <literal>[ "  " [ "FOO" ] "   " ]</literal>.
+
+  </para></listitem>
+  </varlistentry>
+
   <varlistentry><term><function>builtins.stringLength</function>
   <replaceable>e</replaceable></term>
 
@@ -973,8 +1164,8 @@ stdenv.mkDerivation {
   ";
 
   src = fetchurl {
-    url = http://nix.cs.uu.nl/dist/tarballs/hello-2.1.1.tar.gz;
-    md5 = "70c9ccf9fac07f762c24f2df2290784d";
+    url = http://ftp.nluug.nl/pub/gnu/hello/hello-2.1.1.tar.gz;
+    sha256 = "1md7jsfd8pa45z73bz1kszpp01yw6x5ljkjk2hx7wl800any6465";
   };
   inherit perl;
 }</programlisting>
@@ -1208,8 +1399,9 @@ stdenv.mkDerivation (rec {
     <replaceable>e</replaceable>, namely <literal>"int"</literal>,
     <literal>"bool"</literal>, <literal>"string"</literal>,
     <literal>"path"</literal>, <literal>"null"</literal>,
-    <literal>"set"</literal>, <literal>"list"</literal> or
-    <literal>"lambda"</literal>.</para></listitem>
+    <literal>"set"</literal>, <literal>"list"</literal>,
+    <literal>"lambda"</literal> or
+    <literal>"float"</literal>.</para></listitem>
 
   </varlistentry>
 

doc/manual/expressions/debug-build.xml

@@ -1,34 +0,0 @@
-<section xmlns="http://docbook.org/ns/docbook"
-      xmlns:xlink="http://www.w3.org/1999/xlink"
-      xmlns:xi="http://www.w3.org/2001/XInclude"
-      version="5.0"
-      xml:id="sec-debug-build">
-
-<title>Debugging Build Failures</title>
-
-<para>At the beginning of each phase of the build (such as unpacking,
-building or installing), the set of all shell variables is written to
-the file <filename>env-vars</filename> at the top-level build
-directory.  This is useful for debugging: it allows you to recreate
-the environment in which a build was performed.  For instance, if a
-build fails, then assuming you used the <option>-K</option> flag, you
-can go to the output directory and <quote>switch</quote> to the
-environment of the builder:
-
-<screen>
-$ nix-build -K ./foo.nix
-... fails, keeping build directory `/tmp/nix-1234-0'
-
-$ cd /tmp/nix-1234-0
-
-$ source env-vars
-
-<lineannotation>(edit some files...)</lineannotation>
-
-$ make
-
-<lineannotation>(execution continues with the same GCC, make, etc.)</lineannotation></screen>
-
-</para>
-
-</section>

doc/manual/expressions/expression-syntax.xml

@@ -16,7 +16,7 @@ stdenv.mkDerivation { <co xml:id='ex-hello-nix-co-2' />
   builder = ./builder.sh; <co xml:id='ex-hello-nix-co-4' />
   src = fetchurl { <co xml:id='ex-hello-nix-co-5' />
     url = ftp://ftp.nluug.nl/pub/gnu/hello/hello-2.1.1.tar.gz;
-    md5 = "70c9ccf9fac07f762c24f2df2290784d";
+    sha256 = "1md7jsfd8pa45z73bz1kszpp01yw6x5ljkjk2hx7wl800any6465";
   };
   inherit perl; <co xml:id='ex-hello-nix-co-6' />
 }</programlisting>
@@ -108,7 +108,7 @@ the single Nix expression in that directory
     <para>The builder has to know what the sources of the package
     are.  Here, the attribute <varname>src</varname> is bound to the
     result of a call to the <command>fetchurl</command> function.
-    Given a URL and an MD5 hash of the expected contents of the file
+    Given a URL and a SHA-256 hash of the expected contents of the file
     at that URL, this function builds a derivation that downloads the
     file and checks its hash.  So the sources are a dependency that
     like all other dependencies is built before Hello itself is
@@ -145,4 +145,4 @@ perl = perl;</programlisting>
 
 </para>
 
-</section>
+</section>

doc/manual/expressions/language-constructs.xml

@@ -61,7 +61,7 @@ evaluates to <literal>"foobar"</literal>.
 
 <simplesect><title>Inheriting attributes</title>
 
-<para>When defining a set it is often convenient to copy variables
+<para>When defining a set or in a let-expression it is often convenient to copy variables
 from the surrounding lexical scope (e.g., when you want to propagate
 attributes).  This can be shortened using the
 <literal>inherit</literal> keyword.  For instance,
@@ -72,7 +72,15 @@ let x = 123; in
   y = 456;
 }</programlisting>
 
-evaluates to <literal>{ x = 123; y = 456; }</literal>.  (Note that
+is equivalent to
+
+<programlisting>
+let x = 123; in
+{ x = x;
+  y = 456;
+}</programlisting>
+
+and both evaluate to <literal>{ x = 123; y = 456; }</literal>. (Note that
 this works because <varname>x</varname> is added to the lexical scope
 by the <literal>let</literal> construct.)  It is also possible to
 inherit attributes from another set.  For instance, in this fragment
@@ -101,6 +109,26 @@ variables from the surrounding scope (<varname>fetchurl</varname>
 <varname>libXaw</varname> (the X Athena Widgets) from the
 <varname>xlibs</varname> (X11 client-side libraries) set.</para>
 
+<para>
+Summarizing the fragment
+
+<programlisting>
+...
+inherit x y z;
+inherit (src-set) a b c;
+...</programlisting>
+
+is equivalent to
+
+<programlisting>
+...
+x = x; y = y; z = z;
+a = src-set.a; b = src-set.b; c = src-set.c;
+...</programlisting>
+
+when used while defining local variables in a let-expression or
+while defining a set.</para>
+
 </simplesect>
 
 
@@ -333,7 +361,20 @@ with (import ./definitions.nix); ...</programlisting>
 
 makes all attributes defined in the file
 <filename>definitions.nix</filename> available as if they were defined
-locally in a <literal>rec</literal>-expression.</para>
+locally in a <literal>let</literal>-expression.</para>
+
+<para>The bindings introduced by <literal>with</literal> do not shadow bindings
+introduced by other means, e.g.
+
+<programlisting>
+let a = 3; in with { a = 1; }; let a = 4; in with { a = 2; }; ...</programlisting>
+
+establishes the same scope as
+
+<programlisting>
+let a = 1; in let a = 2; in let a = 3; in let a = 4; in ...</programlisting>
+
+</para>
 
 </simplesect>
 

doc/manual/expressions/language-operators.xml

@@ -40,6 +40,11 @@ weakest binding).</para>
         <entry>Call function <replaceable>e1</replaceable> with
         argument <replaceable>e2</replaceable>.</entry>
       </row>
+      <row>
+        <entry><literal>-</literal> <replaceable>e</replaceable></entry>
+        <entry>none</entry>
+        <entry>Arithmetic negation.</entry>
+      </row>
       <row>
         <entry><replaceable>e</replaceable> <literal>?</literal>
         <replaceable>attrpath</replaceable></entry>
@@ -55,13 +60,24 @@ weakest binding).</para>
         <entry>List concatenation.</entry>
       </row>
       <row>
-        <entry><replaceable>e1</replaceable> <literal>+</literal> <replaceable>e2</replaceable></entry>
+        <entry>
+          <replaceable>e1</replaceable> <literal>*</literal> <replaceable>e2</replaceable>,
+          <replaceable>e1</replaceable> <literal>/</literal> <replaceable>e2</replaceable>
+        </entry>
         <entry>left</entry>
-        <entry>String or path concatenation.</entry>
+        <entry>Arithmetic multiplication and division.</entry>
+      </row>
+      <row>
+        <entry>
+          <replaceable>e1</replaceable> <literal>+</literal> <replaceable>e2</replaceable>,
+          <replaceable>e1</replaceable> <literal>-</literal> <replaceable>e2</replaceable>
+        </entry>
+        <entry>left</entry>
+        <entry>Arithmetic addition and subtraction.  String or path concatenation (only by <literal>+</literal>).</entry>
       </row>
       <row>
         <entry><literal>!</literal> <replaceable>e</replaceable></entry>
-        <entry>left</entry>
+        <entry>none</entry>
         <entry>Boolean negation.</entry>
       </row>
       <row>
@@ -75,16 +91,22 @@ weakest binding).</para>
         attributes).</entry>
       </row>
       <row>
-        <entry><replaceable>e1</replaceable> <literal>==</literal>
-        <replaceable>e2</replaceable></entry>
+        <entry>
+          <replaceable>e1</replaceable> <literal>&lt;</literal> <replaceable>e2</replaceable>,
+          <replaceable>e1</replaceable> <literal>&gt;</literal> <replaceable>e2</replaceable>,
+          <replaceable>e1</replaceable> <literal>&lt;=</literal> <replaceable>e2</replaceable>,
+          <replaceable>e1</replaceable> <literal>&gt;=</literal> <replaceable>e2</replaceable>
+        </entry>
         <entry>none</entry>
-        <entry>Equality.</entry>
+        <entry>Arithmetic comparison.</entry>
       </row>
       <row>
-        <entry><replaceable>e1</replaceable> <literal>!=</literal>
-        <replaceable>e2</replaceable></entry>
+        <entry>
+          <replaceable>e1</replaceable> <literal>==</literal> <replaceable>e2</replaceable>,
+          <replaceable>e1</replaceable> <literal>!=</literal> <replaceable>e2</replaceable>
+        </entry>
         <entry>none</entry>
-        <entry>Inequality.</entry>
+        <entry>Equality and inequality.</entry>
       </row>
       <row>
         <entry><replaceable>e1</replaceable> <literal>&amp;&amp;</literal>

doc/manual/expressions/language-values.xml

@@ -98,13 +98,17 @@ configureFlags = "
 
     <para>Since <literal>${</literal> and <literal>''</literal> have
     special meaning in indented strings, you need a way to quote them.
-    <literal>${</literal> can be escaped by prefixing it with
+    <literal>$</literal> can be escaped by prefixing it with
     <literal>''</literal> (that is, two single quotes), i.e.,
-    <literal>''${</literal>.  <literal>''</literal> can be escaped by
+    <literal>''$</literal>. <literal>''</literal> can be escaped by
     prefixing it with <literal>'</literal>, i.e.,
-    <literal>'''</literal>.  Finally, linefeed, carriage-return and
-    tab characters can be written as <literal>''\n</literal>,
-    <literal>''\r</literal>, <literal>''\t</literal>.</para>
+    <literal>'''</literal>. <literal>$</literal> removes any special meaning
+    from the following <literal>$</literal>. Linefeed, carriage-return and tab
+    characters can be written as <literal>''\n</literal>,
+    <literal>''\r</literal>, <literal>''\t</literal>, and <literal>''\</literal>
+    escapes any other character.
+
+    </para>
 
     <para>Indented strings are primarily useful in that they allow
     multi-line string literals to follow the indentation of the

doc/manual/expressions/simple-building-testing.xml

@@ -81,6 +81,4 @@ Just pass the option <link linkend='opt-max-jobs'><option>-j
 in parallel, or set.  Typically this should be the number of
 CPUs.</para>
 
-<xi:include href="debug-build.xml" />
-
 </section>

doc/manual/glossary/glossary.xml

@@ -54,7 +54,7 @@
 
   <glossdef><para>A substitute is a command invocation stored in the
   Nix database that describes how to build a store object, bypassing
-  normal the build mechanism (i.e., derivations).  Typically, the
+  the normal build mechanism (i.e., derivations).  Typically, the
   substitute builds the store object by downloading a pre-built
   version of the store object from some server.</para></glossdef>
 

doc/manual/installation/installing-binary.xml

@@ -6,7 +6,7 @@
 
 <title>Installing a Binary Distribution</title>
 
-<para>If you are using Linux or Mac OS X, the easiest way to install
+<para>If you are using Linux or macOS, the easiest way to install
 Nix is to run the following command:
 
 <screen>
@@ -39,7 +39,7 @@ behaviour.
 <!--
 <para>You can also manually download and install a binary package.
 Binary packages of the latest stable release are available for Fedora,
-Debian, Ubuntu, Mac OS X and various other systems from the <link
+Debian, Ubuntu, macOS and various other systems from the <link
 xlink:href="http://nixos.org/nix/download.html">Nix homepage</link>.
 You can also get builds of the latest development release from our
 <link
@@ -79,16 +79,6 @@ alice$ ./install
 
 </para>
 
-<para>Nix can be uninstalled using <command>rpm -e nix</command> or
-<command>dpkg -r nix</command> on RPM- and Dpkg-based systems,
-respectively.  After this you should manually remove the Nix store and
-other auxiliary data, if desired:
-
-<screen>
-$ rm -rf /nix</screen>
-
-</para>
-
 <para>You can uninstall Nix simply by running:
 
 <screen>

doc/manual/installation/multi-user.xml

@@ -52,34 +52,6 @@ This creates 10 build users. There can never be more concurrent builds
 than the number of build users, so you may want to increase this if
 you expect to do many builds at the same time.</para>
 
-<para>On Mac OS X, you can create the required group and users by
-running the following script:
-
-<programlisting>
-#! /bin/bash -e
-
-dseditgroup -o create nixbld -q
-
-gid=$(dscl . -read /Groups/nixbld | awk '($1 == "PrimaryGroupID:") {print $2 }')
-
-echo "created nixbld group with gid $gid"
-
-for i in $(seq 1 10); do
-    user=/Users/nixbld$i
-    uid="$((30000 + $i))"
-    dscl . create $user
-    dscl . create $user RealName "Nix build user $i"
-    dscl . create $user PrimaryGroupID "$gid"
-    dscl . create $user UserShell /usr/bin/false
-    dscl . create $user NFSHomeDirectory /var/empty
-    dscl . create $user UniqueID "$uid"
-    dseditgroup -o edit -a nixbld$i -t user nixbld
-    echo "created nixbld$i user with uid $uid"
-done
-</programlisting>
-
-</para>
-
 </simplesect>
 
 

doc/manual/installation/prerequisites-source.xml

@@ -10,14 +10,14 @@
 
   <listitem><para>GNU Make.</para></listitem>
 
-  <listitem><para>A version of GCC or Clang that supports C++11.</para></listitem>
+  <listitem><para>A version of GCC or Clang that supports C++14.</para></listitem>
 
   <listitem><para><command>pkg-config</command> to locate
   dependencies.  If your distribution does not provide it, you can get
   it from <link
   xlink:href="http://www.freedesktop.org/wiki/Software/pkg-config"
   />.</para></listitem>
-  
+
   <listitem><para>The OpenSSL library to calculate cryptographic hashes.
   If your distribution does not provide it, you can get it from <link
   xlink:href="https://www.openssl.org"/>.</para></listitem>

doc/manual/installation/supported-platforms.xml

@@ -12,7 +12,7 @@
 
   <listitem><para>Linux (i686, x86_64).</para></listitem>
 
-  <listitem><para>Mac OS X (x86_64).</para></listitem>
+  <listitem><para>macOS (x86_64).</para></listitem>
 
   <!--
   <listitem><para>FreeBSD (only tested on Intel).</para></listitem>
@@ -33,7 +33,4 @@
 
 </para>
 
-<para>Nix is fairly portable, so it should work on most platforms that
-support POSIX threads and have a C++11 compiler.</para>
-
 </chapter>

doc/manual/introduction/about-nix.xml

@@ -236,7 +236,7 @@ href="[%root%]hydra">a continuous build system</a>.</para>
 
 <simplesect><title>Portability</title>
 
-<para>Nix runs on Linux and Mac OS X.</para>
+<para>Nix runs on Linux and macOS.</para>
 
 </simplesect>
 
@@ -262,7 +262,7 @@ xlink:href="http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html">GNU
 LGPLv2.1 or (at your option) any later version</link>.</para>
 
 <para>Nix uses the <link
-xlink:href="https://github.com/antirez/linenoise">linenoise
+xlink:href="https://github.com/arangodb/linenoise-ng">linenoise-ng
 library</link>, which has the following license:</para>
 
 <programlisting><xi:include href="../../../src/linenoise/LICENSE" parse="text" /></programlisting>

doc/manual/introduction/quick-start.xml

@@ -15,7 +15,7 @@ to subsequent chapters.</para>
 <step><para>Install single-user Nix by running the following:
 
 <screen>
-$ curl https://nixos.org/nix/install | sh
+$ bash &lt;(curl https://nixos.org/nix/install)
 </screen>
 
 This will install Nix in <filename>/nix</filename>. The install script

doc/manual/manual.xml

@@ -12,19 +12,14 @@
         <firstname>Eelco</firstname>
         <surname>Dolstra</surname>
       </personname>
-      <affiliation>
-        <orgname>LogicBlox</orgname>
-      </affiliation>
       <contrib>Author</contrib>
     </author>
 
     <copyright>
-      <year>2004-2014</year>
+      <year>2004-2018</year>
       <holder>Eelco Dolstra</holder>
     </copyright>
 
-    <date>November 2014</date>
-
   </info>
 
   <!--
@@ -41,7 +36,6 @@
   <xi:include href="expressions/writing-nix-expressions.xml" />
   <xi:include href="advanced-topics/advanced-topics.xml" />
   <xi:include href="command-ref/command-ref.xml" />
-  <xi:include href="troubleshooting/troubleshooting.xml" />
   <xi:include href="glossary/glossary.xml" />
   <xi:include href="hacking.xml" />
   <xi:include href="release-notes/release-notes.xml" />

doc/manual/packages/ssh-substituter.xml

@@ -12,7 +12,7 @@ automatically fetching any store paths in Firefox’s closure if they
 are available on the server <literal>avalon</literal>:
 
 <screen>
-$ nix-env -i firefox --option ssh-substituter-hosts alice@avalon
+$ nix-env -i firefox --substituters ssh://alice@avalon
 </screen>
 
 This works similar to the binary cache substituter that Nix usually
@@ -31,7 +31,7 @@ an SSH passphrase interactively. Therefore, you should use
 installing it into your profile, e.g.
 
 <screen>
-$ nix-store -r /nix/store/m85bxg…-firefox-34.0.5 --option ssh-substituter-hosts alice@avalon
+$ nix-store -r /nix/store/m85bxg…-firefox-34.0.5 --substituters ssh://alice@avalon
 </screen>
 
 This is essentially equivalent to doing

doc/manual/release-notes/release-notes.xml

@@ -12,7 +12,7 @@
 </partintro>
 -->
 
-<xi:include href="rl-1.12.xml" />
+<xi:include href="rl-2.0.xml" />
 <xi:include href="rl-1.11.10.xml" />
 <xi:include href="rl-1.11.xml" />
 <xi:include href="rl-1.10.xml" />

doc/manual/release-notes/rl-1.12.xml

@@ -1,31 +0,0 @@
-<section xmlns="http://docbook.org/ns/docbook"
-      xmlns:xlink="http://www.w3.org/1999/xlink"
-      xmlns:xi="http://www.w3.org/2001/XInclude"
-      version="5.0"
-      xml:id="ssec-relnotes-1.12">
-
-<title>Release 1.12 (TBA)</title>
-
-<para>This release has the following new features:</para>
-
-<itemizedlist>
-
-  <listitem>
-    <para>It is no longer necessary to set the
-    <envar>NIX_REMOTE</envar> environment variable if you need to use
-    the Nix daemon. Nix will use the daemon automatically if you don’t
-    have write access to the Nix database.</para>
-  </listitem>
-
-  <listitem>
-    <para>The Nix language now supports floating point numbers. They are
-    based on regular C++ <literal>float</literal> and compatible with
-    existing integers and number-related operations. Export and import to and
-    from JSON and XML works, too.
-  </para>
-  </listitem>
-</itemizedlist>
-
-<para>This release has contributions from TBD.</para>
-
-</section>

doc/manual/release-notes/rl-1.2.xml

@@ -40,7 +40,7 @@ $ nix-env -i thunderbird --option binary-caches http://cache.nixos.org
     <para>Binary caches are created using <command>nix-push</command>.
     For details on the operation and format of binary caches, see the
     <command>nix-push</command> manpage.  More details are provided in
-    <link xlink:href="http://lists.science.uu.nl/pipermail/nix-dev/2012-September/009826.html">this
+    <link xlink:href="https://nixos.org/nix-dev/2012-September/009826.html">this
     nix-dev posting</link>.</para>
   </listitem>
 

doc/manual/style.css

@@ -96,7 +96,6 @@ div.example
     margin-right: 1.5em;
     background: #f4f4f8;
     border-radius: 0.4em;
-    box-shadow: 0.4em 0.4em 0.5em #e0e0e0;
 }
 
 div.example p.title
@@ -106,7 +105,6 @@ div.example p.title
 
 div.example pre
 {
-    box-shadow: none;
 }
 
 
@@ -116,15 +114,12 @@ div.example pre
 
 pre.screen, pre.programlisting
 {
-    border: 1px solid #b0b0b0;
-    padding: 3px 3px;
+    padding: 6px 6px;
     margin-left: 1.5em;
     margin-right: 1.5em;
     color: #600000;
     background: #f4f4f8;
     font-family: monospace;
-    border-radius: 0.4em;
-    box-shadow: 0.4em 0.4em 0.5em #e0e0e0;
 }
 
 div.example pre.programlisting
@@ -149,7 +144,6 @@ div.example pre.programlisting
     padding: 0.3em 0.3em 0.3em 0.3em;
     background: #fffff5;
     border-radius: 0.4em;
-    box-shadow: 0.4em 0.4em 0.5em #e0e0e0;
 }
 
 div.note, div.warning
@@ -256,16 +250,14 @@ span.command strong
 
 div.calloutlist table
 {
-    box-shadow: none;
 }
 
 table
 {
     border-collapse: collapse;
-    box-shadow: 0.4em 0.4em 0.5em #e0e0e0;
 }
 
 div.affiliation
 {
     font-style: italic;
-}
+}

doc/manual/troubleshooting/collisions-nixenv.xml

@@ -1,38 +0,0 @@
-<section xmlns="http://docbook.org/ns/docbook"
-      xmlns:xlink="http://www.w3.org/1999/xlink"
-      xmlns:xi="http://www.w3.org/2001/XInclude"
-      version="5.0"
-      xml:id="sec-collisions-nixenv">
-
-<title>Collisions in <command>nix-env</command></title>
-
-<para>Symptom: when installing or upgrading, you get an error message such as
-
-<screen>
-$ nix-env -i docbook-xml
-...
-adding /nix/store/s5hyxgm62gk2...-docbook-xml-4.2
-collision between `/nix/store/s5hyxgm62gk2...-docbook-xml-4.2/xml/dtd/docbook/calstblx.dtd'
-  and `/nix/store/06h377hr4b33...-docbook-xml-4.3/xml/dtd/docbook/calstblx.dtd'
-  at /nix/store/...-builder.pl line 62.</screen>
-
-</para>
-
-<para>The cause is that two installed packages in the user environment
-have overlapping filenames (e.g.,
-<filename>xml/dtd/docbook/calstblx.dtd</filename>.  This usually
-happens when you accidentally try to install two versions of the same
-package.  For instance, in the example above, the Nix Packages
-collection contains two versions of <literal>docbook-xml</literal>, so
-<command>nix-env -i</command> will try to install both.  The default
-user environment builder has no way to way to resolve such conflicts,
-so it just gives up.</para>
-
-<para>Solution: remove one of the offending packages from the user
-environment (if already installed) using <command>nix-env
--e</command>, or specify exactly which version should be installed
-(e.g., <literal>nix-env -i docbook-xml-4.2</literal>).</para>
-
-<!-- FIXME: describe priorities -->
-
-</section>

doc/manual/troubleshooting/links-nix-store.xml

@@ -1,43 +0,0 @@
-<section xmlns="http://docbook.org/ns/docbook"
-      xmlns:xlink="http://www.w3.org/1999/xlink"
-      xmlns:xi="http://www.w3.org/2001/XInclude"
-      version="5.0"
-      xml:id="sec-links-nix-store">
-
-<title><quote>Too many links</quote> Error in the Nix store</title>
-
-
-<para>Symptom: when building something, you get an error message such as
-
-<screen>
-...
-<literal>mkdir: cannot create directory `/nix/store/<replaceable>name</replaceable>': Too many links</literal></screen>
-
-</para>
-
-<para>This is usually because you have more than 32,000 subdirectories
-in <filename>/nix/store</filename>, as can be seen using <command>ls
--l</command>:
-
-<screen>
-$ ls -ld /nix/store
-drwxrwxrwt 32000 nix nix 4620288 Sep 8 15:08 store</screen>
-
-The <literal>ext2</literal> file system is limited to an inode link
-count of 32,000 (each subdirectory increasing the count by one).
-Furthermore, the <literal>st_nlink</literal> field of the
-<function>stat</function> system call is a 16-bit value.</para>
-
-<para>This only happens on very large Nix installations (such as build
-machines).</para>
-
-<para>Quick solution: run the garbage collector.  You may want to use
-the <option>--max-links</option> option.</para>
-
-<para>Real solution: put the Nix store on a file system that supports
-more than 32,000 subdirectories per directory, such as ext4.  (This
-doesn’t solve the <literal>st_nlink</literal> limit, but ext4 lies to
-the kernel by reporting a link count of 1 if it exceeds the
-limit.)</para>
-
-</section>

doc/manual/troubleshooting/troubleshooting.xml

@@ -1,16 +0,0 @@
-<appendix xmlns="http://docbook.org/ns/docbook"
-          xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude"
-          version="5.0"
-          xml:id="ch-troubleshooting">
-
-<title>Troubleshooting</title>
-
-<para>This section provides solutions for some common problems.  See
-the <link xlink:href="https://github.com/NixOS/nix/issues">Nix bug
-tracker</link> for a list of currently known issues.</para>
-
-<xi:include href="collisions-nixenv.xml" />
-<xi:include href="links-nix-store.xml" />
-
-</appendix>

local.mk

@@ -1,6 +1,5 @@
 ifeq ($(MAKECMDGOALS), dist)
-  # Make sure we are in repo root with `--git-dir`
-  dist-files += $(shell git --git-dir=.git ls-files || find * -type f)
+  dist-files += $(shell cat .dist-files)
 endif
 
 dist-files += configure config.h.in nix.spec perl/configure

maintainers/upload-release.pl

@@ -83,6 +83,7 @@ downloadFile("tarball", "3"); # .tar.bz2
 my ($tarball, $tarballHash) = downloadFile("tarball", "4"); # .tar.xz
 my ($tarball_i686_linux, $tarball_i686_linux_hash) = downloadFile("binaryTarball.i686-linux", "1");
 my ($tarball_x86_64_linux, $tarball_x86_64_linux_hash) = downloadFile("binaryTarball.x86_64-linux", "1");
+my ($tarball_aarch64_linux, $tarball_aarch64_linux_hash) = downloadFile("binaryTarball.aarch64-linux", "1");
 my ($tarball_x86_64_darwin, $tarball_x86_64_darwin_hash) = downloadFile("binaryTarball.x86_64-darwin", "1");
 
 # Update Nixpkgs in a very hacky way.
@@ -111,6 +112,7 @@ write_file("$nixpkgsDir/nixos/modules/installer/tools/nix-fallback-paths.nix",
            "{\n" .
            "  x86_64-linux = \"" . getStorePath("build.x86_64-linux") . "\";\n" .
            "  i686-linux = \"" . getStorePath("build.i686-linux") . "\";\n" .
+           "  aarch64-linux = \"" . getStorePath("build.aarch64-linux") . "\";\n" .
            "  x86_64-darwin = \"" . getStorePath("build.x86_64-darwin") . "\";\n" .
            "}\n");
 
@@ -144,6 +146,7 @@ write_file("$siteDir/nix-release.tt",
            "latestNixVersion = \"$version\"\n" .
            "nix_hash_i686_linux = \"$tarball_i686_linux_hash\"\n" .
            "nix_hash_x86_64_linux = \"$tarball_x86_64_linux_hash\"\n" .
+           "nix_hash_aarch64_linux = \"$tarball_aarch64_linux_hash\"\n" .
            "nix_hash_x86_64_darwin = \"$tarball_x86_64_darwin_hash\"\n" .
            "-%]\n");
 

misc/docker/Dockerfile

@@ -1,23 +1,26 @@
 FROM alpine
 
-RUN wget -O- http://nixos.org/releases/nix/nix-1.11.7/nix-1.11.7-x86_64-linux.tar.bz2 | bzcat - | tar xf - \
-    && echo "nixbld:x:30000:nixbld1,nixbld2,nixbld3,nixbld4,nixbld5,nixbld6,nixbld7,nixbld8,nixbld9,nixbld10,nixbld11,nixbld12,nixbld13,nixbld14,nixbld15,nixbld16,nixbld17,nixbld18,nixbld19,nixbld20,nixbld21,nixbld22,nixbld23,nixbld24,nixbld25,nixbld26,nixbld27,nixbld28,nixbld29,nixbld30" >> /etc/group \
-    && for i in $(seq 1 30); do echo "nixbld$i:x:$((30000 + $i)):30000:::" >> /etc/passwd; done \
-    && mkdir -m 0755 /nix && USER=root sh nix-*-x86_64-linux/install \
-    && echo ". /root/.nix-profile/etc/profile.d/nix.sh" >> /etc/profile \
-    && rm -r /nix-*-x86_64-linux \
-    && apk --update add bash tar \
-    && rm -rf /var/cache/apk/*
+# Enable HTTPS support in wget.
+RUN apk add --update openssl
+
+# Download Nix and install it into the system.
+RUN wget -O- https://nixos.org/releases/nix/nix-1.11.14/nix-1.11.14-x86_64-linux.tar.bz2 | bzcat - | tar xf - \
+  && addgroup -g 30000 -S nixbld \
+  && for i in $(seq 1 30); do adduser -S -D -h /var/empty -g "Nix build user $i" -u $((30000 + i)) -G nixbld nixbld$i ; done \
+  && mkdir -m 0755 /nix && USER=root sh nix-*-x86_64-linux/install \
+  && ln -s /nix/var/nix/profiles/default/etc/profile.d/nix.sh /etc/profile.d/ \
+  && rm -r /nix-*-x86_64-linux \
+  && rm -r /var/cache/apk/*
 
 ONBUILD ENV \
     ENV=/etc/profile \
-    PATH=/root/.nix-profile/bin:/root/.nix-profile/sbin:/bin:/sbin:/usr/bin:/usr/sbin \
-    GIT_SSL_CAINFO=/root/.nix-profile/etc/ssl/certs/ca-bundle.crt \
-    NIX_SSL_CERT_FILE=/root/.nix-profile/etc/ssl/certs/ca-bundle.crt
+    PATH=/nix/var/nix/profiles/default/bin:/nix/var/nix/profiles/default/sbin:/bin:/sbin:/usr/bin:/usr/sbin \
+    GIT_SSL_CAINFO=/nix/var/nix/profiles/default/etc/ssl/certs/ca-bundle.crt \
+    NIX_SSL_CERT_FILE=/nix/var/nix/profiles/default/etc/ssl/certs/ca-bundle.crt
 
 ENV \
     ENV=/etc/profile \
-    PATH=/root/.nix-profile/bin:/root/.nix-profile/sbin:/bin:/sbin:/usr/bin:/usr/sbin \
-    GIT_SSL_CAINFO=/root/.nix-profile/etc/ssl/certs/ca-bundle.crt \
-    NIX_SSL_CERT_FILE=/root/.nix-profile/etc/ssl/certs/ca-bundle.crt \
-    NIX_PATH=/nix/var/nix/profiles/per-user/root/channels/
+    PATH=/nix/var/nix/profiles/default/bin:/nix/var/nix/profiles/default/sbin:/bin:/sbin:/usr/bin:/usr/sbin \
+    GIT_SSL_CAINFO=/nix/var/nix/profiles/default/etc/ssl/certs/ca-bundle.crt \
+    NIX_SSL_CERT_FILE=/nix/var/nix/profiles/default/etc/ssl/certs/ca-bundle.crt \
+    NIX_PATH=/nix/var/nix/profiles/per-user/root/channels

misc/emacs/README

@@ -1,10 +0,0 @@
-The Nix Emacs mode supports syntax highlighting, somewhat sensible
-indenting, and refilling of comments.
-
-To enable Nix mode in Emacs, add something like this to your ~/.emacs
-file:
-
-  (load "/nix/share/emacs/site-lisp/nix-mode.el")
-
-This automatically causes Nix mode to be activated for all files with
-extension `.nix'.

misc/emacs/local.mk

@@ -1 +0,0 @@
-$(eval $(call install-data-in,$(d)/nix-mode.el,$(datadir)/emacs/site-lisp))

misc/emacs/nix-mode.el

@@ -1,177 +0,0 @@
-;;; nix-mode.el --- Major mode for editing Nix expressions
-
-;; Author: Eelco Dolstra
-;; URL: https://github.com/NixOS/nix/tree/master/misc/emacs
-;; Version: 1.0
-
-;;; Commentary:
-
-;;; Code:
-
-(defun nix-syntax-match-antiquote (limit)
-  (let ((pos (next-single-char-property-change (point) 'nix-syntax-antiquote
-                                               nil limit)))
-    (when (and pos (> pos (point)))
-      (goto-char pos)
-      (let ((char (char-after pos)))
-        (pcase char
-          (`?$
-           (forward-char 2))
-          (`?}
-           (forward-char 1)))
-        (set-match-data (list pos (point)))
-        t))))
-
-(defconst nix-font-lock-keywords
-  '("\\_<if\\_>" "\\_<then\\_>" "\\_<else\\_>" "\\_<assert\\_>" "\\_<with\\_>"
-    "\\_<let\\_>" "\\_<in\\_>" "\\_<rec\\_>" "\\_<inherit\\_>" "\\_<or\\_>"
-    ("\\_<true\\_>" . font-lock-builtin-face)
-    ("\\_<false\\_>" . font-lock-builtin-face)
-    ("\\_<null\\_>" . font-lock-builtin-face)
-    ("\\_<import\\_>" . font-lock-builtin-face)
-    ("\\_<derivation\\_>" . font-lock-builtin-face)
-    ("\\_<baseNameOf\\_>" . font-lock-builtin-face)
-    ("\\_<toString\\_>" . font-lock-builtin-face)
-    ("\\_<isNull\\_>" . font-lock-builtin-face)
-    ("[a-zA-Z][a-zA-Z0-9\\+-\\.]*:[a-zA-Z0-9%/\\?:@&=\\+\\$,_\\.!~\\*'-]+"
-     . font-lock-constant-face)
-    ("\\<\\([a-zA-Z_][a-zA-Z0-9_'\-\.]*\\)[ \t]*="
-     (1 font-lock-variable-name-face nil nil))
-    ("<[a-zA-Z0-9._\\+-]+\\(/[a-zA-Z0-9._\\+-]+\\)*>"
-     . font-lock-constant-face)
-    ("[a-zA-Z0-9._\\+-]*\\(/[a-zA-Z0-9._\\+-]+\\)+"
-     . font-lock-constant-face)
-    (nix-syntax-match-antiquote 0 font-lock-preprocessor-face t))
-  "Font lock keywords for nix.")
-
-(defvar nix-mode-syntax-table
-  (let ((table (make-syntax-table)))
-    (modify-syntax-entry ?/ ". 14" table)
-    (modify-syntax-entry ?* ". 23" table)
-    (modify-syntax-entry ?# "< b" table)
-    (modify-syntax-entry ?\n "> b" table)
-    table)
-  "Syntax table for Nix mode.")
-
-(defun nix-syntax-propertize-escaped-antiquote ()
-  "Set syntax properies for escaped antiquote marks."
-  nil)
-
-(defun nix-syntax-propertize-multiline-string ()
-  "Set syntax properies for multiline string delimiters."
-  (let* ((start (match-beginning 0))
-         (end (match-end 0))
-         (context (save-excursion (save-match-data (syntax-ppss start))))
-         (string-type (nth 3 context)))
-    (pcase string-type
-      (`t
-       ;; inside a multiline string
-       ;; ending multi-line string delimiter
-       (put-text-property (1- end) end
-                          'syntax-table (string-to-syntax "|")))
-      (`nil
-       ;; beginning multi-line string delimiter
-       (put-text-property start (1+ start)
-                          'syntax-table (string-to-syntax "|"))))))
-
-(defun nix-syntax-propertize-antiquote ()
-  "Set syntax properties for antiquote marks."
-  (let* ((start (match-beginning 0)))
-    (put-text-property start (1+ start)
-                       'syntax-table (string-to-syntax "|"))
-    (put-text-property start (+ start 2)
-                       'nix-syntax-antiquote t)))
-
-(defun nix-syntax-propertize-close-brace ()
-  "Set syntax properties for close braces.
-If a close brace `}' ends an antiquote, the next character begins a string."
-  (let* ((start (match-beginning 0))
-         (end (match-end 0))
-         (context (save-excursion (save-match-data (syntax-ppss start))))
-         (open (nth 1 context)))
-    (when open ;; a corresponding open-brace was found
-      (let* ((antiquote (get-text-property open 'nix-syntax-antiquote)))
-        (when antiquote
-          (put-text-property (+ start 1) (+ start 2)
-                             'syntax-table (string-to-syntax "|"))
-          (put-text-property start (1+ start)
-                             'nix-syntax-antiquote t))))))
-
-(defun nix-syntax-propertize (start end)
-  "Special syntax properties for Nix."
-  ;; search for multi-line string delimiters
-  (goto-char start)
-  (remove-text-properties start end '(syntax-table nil nix-syntax-antiquote nil))
-  (funcall
-   (syntax-propertize-rules
-    ("''\\${"
-     (0 (ignore (nix-syntax-propertize-escaped-antiquote))))
-    ("''"
-     (0 (ignore (nix-syntax-propertize-multiline-string))))
-    ("\\${"
-     (0 (ignore (nix-syntax-propertize-antiquote))))
-    ("}"
-     (0 (ignore (nix-syntax-propertize-close-brace)))))
-   start end))
-
-(defun nix-indent-line ()
-  "Indent current line in a Nix expression."
-  (interactive)
-  (indent-relative-maybe))
-
-
-;;;###autoload
-(define-derived-mode nix-mode prog-mode "Nix"
-  "Major mode for editing Nix expressions.
-
-The following commands may be useful:
-
-  '\\[newline-and-indent]'
-    Insert a newline and move the cursor to align with the previous
-    non-empty line.
-
-  '\\[fill-paragraph]'
-    Refill a paragraph so that all lines are at most `fill-column'
-    lines long.  This should do the right thing for comments beginning
-    with `#'.  However, this command doesn't work properly yet if the
-    comment is adjacent to code (i.e., no intervening empty lines).
-    In that case, select the text to be refilled and use
-    `\\[fill-region]' instead.
-
-The hook `nix-mode-hook' is run when Nix mode is started.
-
-\\{nix-mode-map}
-"
-  (set-syntax-table nix-mode-syntax-table)
-
-  ;; Font lock support.
-  (setq-local font-lock-defaults '(nix-font-lock-keywords nil nil nil nil))
-
-  ;; Special syntax properties for Nix
-  (setq-local syntax-propertize-function 'nix-syntax-propertize)
-
-  ;; Look at text properties when parsing
-  (setq-local parse-sexp-lookup-properties t)
-
-  ;; Automatic indentation [C-j].
-  (set (make-local-variable 'indent-line-function) 'nix-indent-line)
-
-  ;; Indenting of comments.
-  (set (make-local-variable 'comment-start) "# ")
-  (set (make-local-variable 'comment-end) "")
-  (set (make-local-variable 'comment-start-skip) "\\(^\\|\\s-\\);?#+ *")
-
-  ;; Filling of comments.
-  (set (make-local-variable 'adaptive-fill-mode) t)
-  (set (make-local-variable 'paragraph-start) "[ \t]*\\(#+[ \t]*\\)?$")
-  (set (make-local-variable 'paragraph-separate) paragraph-start))
-
-
-;;;###autoload
-(progn
-  (add-to-list 'auto-mode-alist '("\\.nix\\'" . nix-mode))
-  (add-to-list 'auto-mode-alist '("\\.nix.in\\'" . nix-mode)))
-
-(provide 'nix-mode)
-
-;;; nix-mode.el ends here

misc/launchd/org.nixos.nix-daemon.plist.in

@@ -4,6 +4,8 @@
   <dict>
     <key>Label</key>
     <string>org.nixos.nix-daemon</string>
+    <key>KeepAlive</key>
+    <true/>
     <key>RunAtLoad</key>
     <true/>
     <key>Program</key>

mk/libraries.mk

@@ -45,6 +45,11 @@ endif
 # - $(1)_INSTALL_DIR: the directory where the library will be
 #   installed.  Defaults to $(libdir).
 #
+# - $(1)_EXCLUDE_FROM_LIBRARY_LIST: if defined, the library will not
+#   be automatically marked as a dependency of the top-level all
+#   target andwill not be listed in the make help output. This is
+#   useful for libraries built solely for testing, for example.
+#
 # - BUILD_SHARED_LIBS: if equal to ‘1’, a dynamic library will be
 #   built, otherwise a static library.
 define build-library
@@ -149,7 +154,9 @@ define build-library
   $(1)_DEPS := $$(foreach fn, $$($(1)_OBJS), $$(call filename-to-dep, $$(fn)))
   -include $$($(1)_DEPS)
 
+  ifndef $(1)_EXCLUDE_FROM_LIBRARY_LIST
   libs-list += $$($(1)_PATH)
+  endif
   clean-files += $$(_d)/*.a $$(_d)/*.$(SO_EXT) $$(_d)/*.o $$(_d)/.*.dep $$($(1)_DEPS) $$($(1)_OBJS)
   dist-files += $$(_srcs)
 endef

mk/programs.mk

@@ -51,7 +51,7 @@ define build-program
   else
 
     $(DESTDIR)$$($(1)_INSTALL_PATH): $$($(1)_PATH) | $(DESTDIR)$$($(1)_INSTALL_DIR)/
-	install -t $$($(1)_INSTALL_DIR) $$<
+	install -t $(DESTDIR)$$($(1)_INSTALL_DIR) $$<
 
   endif
 

mk/tests.mk

@@ -7,20 +7,39 @@ define run-install-test
 
 endef
 
+# Color code from https://unix.stackexchange.com/a/10065
 installcheck:
-	@total=0; failed=0; for i in $(_installcheck-list); do \
+	@total=0; failed=0; \
+	red=""; \
+	green=""; \
+	yellow=""; \
+	normal=""; \
+	if [ -t 1 ]; then \
+		red=""; \
+		green=""; \
+		yellow=""; \
+		normal=""; \
+	fi; \
+	for i in $(_installcheck-list); do \
 	  total=$$((total + 1)); \
-	  echo "running test $$i"; \
-	  if (cd $$(dirname $$i) && $(tests-environment) $$(basename $$i)); then \
-	    echo "PASS: $$i"; \
+	  printf "running test $$i..."; \
+	  log="$$(cd $$(dirname $$i) && $(tests-environment) $$(basename $$i) 2>&1)"; \
+	  status=$$?; \
+	  if [ $$status -eq 0 ]; then \
+	    echo " [$${green}PASS$$normal]"; \
+	  elif [ $$status -eq 99 ]; then \
+	    echo " [$${yellow}SKIP$$normal]"; \
 	  else \
-	    echo "FAIL: $$i"; \
+	    echo " [$${red}FAIL$$normal]"; \
+	    echo "$$log" | sed 's/^/    /'; \
 	    failed=$$((failed + 1)); \
 	  fi; \
 	done; \
 	if [ "$$failed" != 0 ]; then \
-	  echo "$$failed out of $$total tests failed "; \
+	  echo "$${red}$$failed out of $$total tests failed $$normal"; \
 	  exit 1; \
+	else \
+		echo "$${green}All tests succeeded$$normal"; \
 	fi
 
 .PHONY: check installcheck

nix.spec.in

@@ -60,33 +60,6 @@ Requires:       %{name} = %{version}-%{release}
 %description   doc
 The %{name}-doc package contains documentation files for %{name}.
 
-
-%package -n emacs-%{name}
-Summary:        Nix mode for Emacs
-%if 0%{?rhel} && 0%{?rhel} < 7
-Group:          Applications/Editors
-%endif
-BuildArch:      noarch
-BuildRequires:  emacs
-Requires:       emacs(bin) >= %{_emacs_version}
-
-%description -n emacs-%{name}
-This package provides a major mode for editing Nix expressions.
-
-%package -n emacs-%{name}-el
-Summary:        Elisp source files for emacs-%{name}
-%if 0%{?rhel} && 0%{?rhel} < 7
-Group:          Applications/Editors
-%endif
-BuildArch:      noarch
-Requires:       emacs-%{name} = %{version}-%{release}
-
-%description -n emacs-%{name}-el
-This package contains the elisp source file for the Nix major mode for
-GNU Emacs. You do not need to install this package to run Nix. Install
-the emacs-%{name} package to edit Nix expressions with GNU Emacs.
-
-
 %prep
 %setup -q
 
@@ -100,7 +73,6 @@ extraFlags=
            --docdir=%{_defaultdocdir}/%{name}-doc-%{version} \
            $extraFlags
 make -j$NIX_BUILD_CORES -l$NIX_BUILD_CORES
-%{_emacs_bytecompile} misc/emacs/nix-mode.el
 
 
 %install
@@ -126,9 +98,6 @@ done
 # (until this is fixed in the relevant Makefile)
 chmod -x $RPM_BUILD_ROOT%{_sysconfdir}/profile.d/nix.sh
 
-# Copy the byte-compiled mode file by hand
-cp -p misc/emacs/nix-mode.elc $RPM_BUILD_ROOT%{_emacs_sitelispdir}/
-
 # we ship this file in the base package
 rm -f $RPM_BUILD_ROOT%{_defaultdocdir}/%{name}-doc-%{version}/README
 
@@ -166,12 +135,12 @@ systemctl start  nix-daemon.socket
 %{_prefix}/lib/systemd/system/nix-daemon.socket
 %{_prefix}/lib/systemd/system/nix-daemon.service
 %endif
-%{_datadir}/emacs/site-lisp/nix-mode.el
 %{_datadir}/nix
 %{_mandir}/man1/*.1*
 %{_mandir}/man5/*.5*
 %{_mandir}/man8/*.8*
 %config(noreplace) %{_sysconfdir}/profile.d/nix.sh
+%config(noreplace) %{_sysconfdir}/profile.d/nix-daemon.sh
 /nix
 
 %files devel
@@ -181,10 +150,3 @@ systemctl start  nix-daemon.socket
 %files doc
 %docdir %{_defaultdocdir}/%{name}-doc-%{version}
 %{_defaultdocdir}/%{name}-doc-%{version}
-
-%files -n emacs-%{name}
-%{_emacs_sitelispdir}/*.elc
-#{_emacs_sitestartdir}/*.el
-
-%files -n emacs-%{name}-el
-%{_emacs_sitelispdir}/*.el

perl/lib/Nix/Config.pm.in

@@ -23,7 +23,7 @@ sub readConfig {
     my $config = "$confDir/nix.conf";
     return unless -f $config;
 
-    open CONFIG, "<$config" or die "cannot open ‘$config’";
+    open CONFIG, "<$config" or die "cannot open '$config'";
     while (<CONFIG>) {
         /^\s*([\w\-\.]+)\s*=\s*(.*)$/ or next;
         $config{$1} = $2;

perl/lib/Nix/CopyClosure.pm

@@ -35,14 +35,14 @@ sub copyToOpen {
     my $missingSize = 0;
     $missingSize += (queryPathInfo($_, 1))[3] foreach @missing;
 
-    printf STDERR "copying %d missing paths (%.2f MiB) to ‘$sshHost’...\n",
+    printf STDERR "copying %d missing paths (%.2f MiB) to '$sshHost'...\n",
         scalar(@missing), $missingSize / (1024**2);
     return if $dryRun;
 
     # Send the "import paths" command.
     syswrite($to, pack("L<x4", 4)) or die;
     exportPaths(fileno($to), @missing);
-    readInt($from) == 1 or die "remote machine ‘$sshHost’ failed to import closure\n";
+    readInt($from) == 1 or die "remote machine '$sshHost' failed to import closure\n";
 }
 
 

perl/lib/Nix/Manifest.pm

@@ -60,10 +60,10 @@ sub readManifest_ {
     # Decompress the manifest if necessary.
     if ($manifest =~ /\.bz2$/) {
         open MANIFEST, "$Nix::Config::bzip2 -d < $manifest |"
-            or die "cannot decompress ‘$manifest’: $!";
+            or die "cannot decompress '$manifest': $!";
     } else {
         open MANIFEST, "<$manifest"
-            or die "cannot open ‘$manifest’: $!";
+            or die "cannot open '$manifest': $!";
     }
 
     my $inside = 0;
@@ -287,7 +287,7 @@ sub parseNARInfo {
         # FIXME: might be useful to support multiple signatures per .narinfo.
 
         if (!defined $sig) {
-            warn "NAR info file ‘$location’ lacks a signature; ignoring\n";
+            warn "NAR info file '$location' lacks a signature; ignoring\n";
             return undef;
         }
         my ($keyName, $sig64) = split ":", $sig;
@@ -295,7 +295,7 @@ sub parseNARInfo {
 
         my $publicKey = $Nix::Config::binaryCachePublicKeys{$keyName};
         if (!defined $publicKey) {
-            warn "NAR info file ‘$location’ is signed by unknown key ‘$keyName’; ignoring\n";
+            warn "NAR info file '$location' is signed by unknown key '$keyName'; ignoring\n";
             return undef;
         }
 
@@ -306,12 +306,12 @@ sub parseNARInfo {
                 [ map { "$Nix::Config::storeDir/$_" } @refs ]);
         };
         if ($@) {
-            warn "cannot compute fingerprint of ‘$location’; ignoring\n";
+            warn "cannot compute fingerprint of '$location'; ignoring\n";
             return undef;
         }
 
         if (!checkSignature($publicKey, decode_base64($sig64), $fingerprint)) {
-            warn "NAR info file ‘$location’ has an incorrect signature; ignoring\n";
+            warn "NAR info file '$location' has an incorrect signature; ignoring\n";
             return undef;
         }
 

perl/lib/Nix/SSH.pm

@@ -97,7 +97,7 @@ sub connectToRemoteNix {
         syswrite($to, pack("L<x4L<x4", $SERVE_MAGIC_1, $clientVersion)) or die;
         $magic = readInt($from);
     };
-    die "unable to connect to ‘$sshHost’\n" if $@;
+    die "unable to connect to '$sshHost'\n" if $@;
     die "did not get valid handshake from remote host\n" if $magic  != 0x5452eecb;
 
     my $serverVersion = readInt($from);

perl/lib/Nix/Store.xs

@@ -81,8 +81,7 @@ SV * queryReferences(char * path)
 SV * queryPathHash(char * path)
     PPCODE:
         try {
-            auto hash = store()->queryPathInfo(path)->narHash;
-            string s = "sha256:" + printHash32(hash);
+            auto s = store()->queryPathInfo(path)->narHash.to_string();
             XPUSHs(sv_2mortal(newSVpv(s.c_str(), 0)));
         } catch (Error & e) {
             croak("%s", e.what());
@@ -108,7 +107,7 @@ SV * queryPathInfo(char * path, int base32)
                 XPUSHs(&PL_sv_undef);
             else
                 XPUSHs(sv_2mortal(newSVpv(info->deriver.c_str(), 0)));
-            string s = "sha256:" + (base32 ? printHash32(info->narHash) : printHash(info->narHash));
+            auto s = info->narHash.to_string(base32 ? Base32 : Base16);
             XPUSHs(sv_2mortal(newSVpv(s.c_str(), 0)));
             mXPUSHi(info->registrationTime);
             mXPUSHi(info->narSize);
@@ -184,7 +183,7 @@ void importPaths(int fd, int dontCheckSigs)
     PPCODE:
         try {
             FdSource source(fd);
-            store()->importPaths(source, 0, dontCheckSigs);
+            store()->importPaths(source, nullptr, dontCheckSigs ? NoCheckSigs : CheckSigs);
         } catch (Error & e) {
             croak("%s", e.what());
         }
@@ -194,7 +193,7 @@ SV * hashPath(char * algo, int base32, char * path)
     PPCODE:
         try {
             Hash h = hashPath(parseHashType(algo), path).first;
-            string s = base32 ? printHash32(h) : printHash(h);
+            auto s = h.to_string(base32 ? Base32 : Base16, false);
             XPUSHs(sv_2mortal(newSVpv(s.c_str(), 0)));
         } catch (Error & e) {
             croak("%s", e.what());
@@ -205,7 +204,7 @@ SV * hashFile(char * algo, int base32, char * path)
     PPCODE:
         try {
             Hash h = hashFile(parseHashType(algo), path);
-            string s = base32 ? printHash32(h) : printHash(h);
+            auto s = h.to_string(base32 ? Base32 : Base16, false);
             XPUSHs(sv_2mortal(newSVpv(s.c_str(), 0)));
         } catch (Error & e) {
             croak("%s", e.what());
@@ -216,7 +215,7 @@ SV * hashString(char * algo, int base32, char * s)
     PPCODE:
         try {
             Hash h = hashString(parseHashType(algo), s);
-            string s = base32 ? printHash32(h) : printHash(h);
+            auto s = h.to_string(base32 ? Base32 : Base16, false);
             XPUSHs(sv_2mortal(newSVpv(s.c_str(), 0)));
         } catch (Error & e) {
             croak("%s", e.what());
@@ -226,8 +225,8 @@ SV * hashString(char * algo, int base32, char * s)
 SV * convertHash(char * algo, char * s, int toBase32)
     PPCODE:
         try {
-            Hash h = parseHash16or32(parseHashType(algo), s);
-            string s = toBase32 ? printHash32(h) : printHash(h);
+            Hash h(s, parseHashType(algo));
+            string s = h.to_string(toBase32 ? Base32 : Base16, false);
             XPUSHs(sv_2mortal(newSVpv(s.c_str(), 0)));
         } catch (Error & e) {
             croak("%s", e.what());
@@ -286,8 +285,7 @@ SV * addToStore(char * srcPath, int recursive, char * algo)
 SV * makeFixedOutputPath(int recursive, char * algo, char * hash, char * name)
     PPCODE:
         try {
-            HashType ht = parseHashType(algo);
-            Hash h = parseHash16or32(ht, hash);
+            Hash h(hash, parseHashType(algo));
             Path path = store()->makeFixedOutputPath(recursive, h, name);
             XPUSHs(sv_2mortal(newSVpv(path.c_str(), 0)));
         } catch (Error & e) {

perl/lib/Nix/Utils.pm

@@ -10,7 +10,7 @@ $urlRE = "(?: [a-zA-Z][a-zA-Z0-9\+\-\.]*\:[a-zA-Z0-9\%\/\?\:\@\&\=\+\$\,\-\_\.\!
 
 sub checkURL {
     my ($url) = @_;
-    die "invalid URL ‘$url’\n" unless $url =~ /^ $urlRE $ /x;
+    die "invalid URL '$url'\n" unless $url =~ /^ $urlRE $ /x;
 }
 
 sub uniq {
@@ -26,7 +26,7 @@ sub uniq {
 
 sub writeFile {
     my ($fn, $s) = @_;
-    open TMP, ">$fn" or die "cannot create file ‘$fn’: $!";
+    open TMP, ">$fn" or die "cannot create file '$fn': $!";
     print TMP "$s" or die;
     close TMP or die;
 }
@@ -34,7 +34,7 @@ sub writeFile {
 sub readFile {
     local $/ = undef;
     my ($fn) = @_;
-    open TMP, "<$fn" or die "cannot open file ‘$fn’: $!";
+    open TMP, "<$fn" or die "cannot open file '$fn': $!";
     my $s = <TMP>;
     close TMP or die;
     return $s;

release-common.nix

@@ -1,17 +1,31 @@
 { pkgs }:
 
 rec {
-  sh = pkgs.busybox.override {
+  # Use "busybox-sandbox-shell" if present,
+  # if not (legacy) fallback and hope it's sufficient.
+  sh = pkgs.busybox-sandbox-shell or (pkgs.busybox.override {
     useMusl = true;
     enableStatic = true;
     enableMinimal = true;
     extraConfig = ''
+      CONFIG_FEATURE_FANCY_ECHO y
+      CONFIG_FEATURE_SH_MATH y
+      CONFIG_FEATURE_SH_MATH_64 y
+
       CONFIG_ASH y
-      CONFIG_ASH_BUILTIN_ECHO y
-      CONFIG_ASH_BUILTIN_TEST y
       CONFIG_ASH_OPTIMIZE_FOR_SIZE y
+
+      CONFIG_ASH_ALIAS y
+      CONFIG_ASH_BASH_COMPAT y
+      CONFIG_ASH_CMDCMD y
+      CONFIG_ASH_ECHO y
+      CONFIG_ASH_GETOPTS y
+      CONFIG_ASH_INTERNAL_GLOB y
+      CONFIG_ASH_JOB_CONTROL y
+      CONFIG_ASH_PRINTF y
+      CONFIG_ASH_TEST y
     '';
-  };
+  });
 
   configureFlags =
     [ "--disable-init-state"

release.nix

@@ -1,14 +1,12 @@
-{ nix ? { outPath = ./.; revCount = 1234; shortRev = "abcdef"; }
-, nixpkgs ? { outPath = <nixpkgs>; revCount = 1234; shortRev = "abcdef"; }
+{ nix ? builtins.fetchGit ./.
+, nixpkgs ? builtins.fetchGit https://github.com/NixOS/nixpkgs.git
 , officialRelease ? false
+, systems ? [ "x86_64-linux" "i686-linux" "x86_64-darwin" "aarch64-linux" ]
 }:
 
 let
 
-  pkgs = import <nixpkgs> {};
-
-  systems = [ "x86_64-linux" "i686-linux" "x86_64-darwin" "aarch64-linux" ];
-
+  pkgs = import nixpkgs { system = builtins.currentSystem or "x86_64-linux"; };
 
   jobs = rec {
 
@@ -29,17 +27,13 @@ let
             pkgconfig sqlite libsodium boehmgc
             docbook5 docbook5_xsl
             autoconf-archive
-            git
-            libseccomp
-          ];
+          ] ++ lib.optional stdenv.isLinux libseccomp;
 
         configureFlags = "--enable-gc";
 
         postUnpack = ''
-          # Clean up when building from a working tree.
-          if [[ -d $sourceRoot/.git ]]; then
-            git -C $sourceRoot clean -fd
-          fi
+          (cd source && find . -type f) | cut -c3- > source/.dist-files
+          cat source/.dist-files
         '';
 
         preConfigure = ''
@@ -65,7 +59,7 @@ let
 
     build = pkgs.lib.genAttrs systems (system:
 
-      with import <nixpkgs> { inherit system; };
+      with import nixpkgs { inherit system; };
 
       with import ./release-common.nix { inherit pkgs; };
 
@@ -78,6 +72,9 @@ let
             bzip2 xz brotli
             openssl pkgconfig sqlite boehmgc
 
+            # Tests
+            git
+            mercurial
           ]
           ++ lib.optional stdenv.isLinux libseccomp
           ++ lib.optional (stdenv.isLinux || stdenv.isDarwin) libsodium
@@ -105,7 +102,7 @@ let
 
     perlBindings = pkgs.lib.genAttrs systems (system:
 
-      let pkgs = import <nixpkgs> { inherit system; }; in with pkgs;
+      let pkgs = import nixpkgs { inherit system; }; in with pkgs;
 
       releaseTools.nixBuild {
         name = "nix-perl";
@@ -130,26 +127,56 @@ let
 
     binaryTarball = pkgs.lib.genAttrs systems (system:
 
-      # FIXME: temporarily use a different branch for the Darwin build.
-      with import <nixpkgs> { inherit system; };
+      with import nixpkgs { inherit system; };
 
       let
         toplevel = builtins.getAttr system jobs.build;
         version = toplevel.src.version;
+        installerClosureInfo = closureInfo { rootPaths = [ toplevel cacert ]; };
       in
 
       runCommand "nix-binary-tarball-${version}"
-        { exportReferencesGraph = [ "closure1" toplevel "closure2" cacert ];
-          buildInputs = [ perl ];
+        { nativeBuildInputs = lib.optional (system != "aarch64-linux") shellcheck;
           meta.description = "Distribution-independent Nix bootstrap binaries for ${system}";
         }
         ''
-          storePaths=$(perl ${pathsFromGraph} ./closure1 ./closure2)
-          printRegistration=1 perl ${pathsFromGraph} ./closure1 ./closure2 > $TMPDIR/reginfo
+          cp ${installerClosureInfo}/registration $TMPDIR/reginfo
           substitute ${./scripts/install-nix-from-closure.sh} $TMPDIR/install \
             --subst-var-by nix ${toplevel} \
             --subst-var-by cacert ${cacert}
+
+          substitute ${./scripts/install-darwin-multi-user.sh} $TMPDIR/install-darwin-multi-user.sh \
+            --subst-var-by nix ${toplevel} \
+            --subst-var-by cacert ${cacert}
+          substitute ${./scripts/install-systemd-multi-user.sh} $TMPDIR/install-systemd-multi-user.sh \
+            --subst-var-by nix ${toplevel} \
+            --subst-var-by cacert ${cacert}
+          substitute ${./scripts/install-multi-user.sh} $TMPDIR/install-multi-user \
+            --subst-var-by nix ${toplevel} \
+            --subst-var-by cacert ${cacert}
+
+          if type -p shellcheck; then
+            # SC1090: Don't worry about not being able to find
+            #         $nix/etc/profile.d/nix.sh
+            shellcheck --exclude SC1090 $TMPDIR/install
+            shellcheck $TMPDIR/install-darwin-multi-user.sh
+            shellcheck $TMPDIR/install-systemd-multi-user.sh
+
+            # SC1091: Don't panic about not being able to source
+            #         /etc/profile
+            # SC2002: Ignore "useless cat" "error", when loading
+            #         .reginfo, as the cat is a much cleaner
+            #         implementation, even though it is "useless"
+            # SC2116: Allow ROOT_HOME=$(echo ~root) for resolving
+            #         root's home directory
+            shellcheck --external-sources \
+              --exclude SC1091,SC2002,SC2116 $TMPDIR/install-multi-user
+          fi
+
           chmod +x $TMPDIR/install
+          chmod +x $TMPDIR/install-darwin-multi-user.sh
+          chmod +x $TMPDIR/install-systemd-multi-user.sh
+          chmod +x $TMPDIR/install-multi-user
           dir=nix-${version}-${system}
           fn=$out/$dir.tar.bz2
           mkdir -p $out/nix-support
@@ -161,12 +188,15 @@ let
             --transform "s,$TMPDIR/install,$dir/install," \
             --transform "s,$TMPDIR/reginfo,$dir/.reginfo," \
             --transform "s,$NIX_STORE,$dir/store,S" \
-            $TMPDIR/install $TMPDIR/reginfo $storePaths
+            $TMPDIR/install $TMPDIR/install-darwin-multi-user.sh \
+            $TMPDIR/install-systemd-multi-user.sh \
+            $TMPDIR/install-multi-user $TMPDIR/reginfo \
+            $(cat ${installerClosureInfo}/store-paths)
         '');
 
 
     coverage =
-      with import <nixpkgs> { system = "x86_64-linux"; };
+      with import nixpkgs { system = "x86_64-linux"; };
 
       releaseTools.coverageAnalysis {
         name = "nix-build";
@@ -175,7 +205,7 @@ let
         buildInputs =
           [ curl bzip2 openssl pkgconfig sqlite xz libsodium libseccomp
             # These are for "make check" only:
-            graphviz libxml2 libxslt
+            graphviz libxml2 libxslt git mercurial
           ];
 
         configureFlags = ''
@@ -186,7 +216,7 @@ let
 
         doInstallCheck = true;
 
-        lcovFilter = [ "*/boost/*" "*-tab.*" ];
+        lcovFilter = [ "*/boost/*" "*-tab.*" "*/nlohmann/*" "*/linenoise/*" ];
 
         # We call `dot', and even though we just use it to
         # syntax-check generated dot files, it still requires some
@@ -195,37 +225,38 @@ let
       };
 
 
-    rpm_fedora25i386 = makeRPM_i686 (diskImageFuns: diskImageFuns.fedora25i386) [ "libsodium-devel" ];
-    rpm_fedora25x86_64 = makeRPM_x86_64 (diskImageFunsFun: diskImageFunsFun.fedora25x86_64) [ "libsodium-devel" ];
+    rpm_fedora27i386 = makeRPM_i686 (diskImageFuns: diskImageFuns.fedora27i386) [ "libsodium-devel" ];
+    rpm_fedora27x86_64 = makeRPM_x86_64 (diskImageFunsFun: diskImageFunsFun.fedora27x86_64) [ "libsodium-devel" ];
 
 
-    deb_debian8i386 = makeDeb_i686 (diskImageFuns: diskImageFuns.debian8i386) [ "libsodium-dev" ] [ "libsodium13" ];
-    deb_debian8x86_64 = makeDeb_x86_64 (diskImageFunsFun: diskImageFunsFun.debian8x86_64) [ "libsodium-dev" ] [ "libsodium13" ];
+    #deb_debian8i386 = makeDeb_i686 (diskImageFuns: diskImageFuns.debian8i386) [ "libsodium-dev" ] [ "libsodium13" ];
+    #deb_debian8x86_64 = makeDeb_x86_64 (diskImageFunsFun: diskImageFunsFun.debian8x86_64) [ "libsodium-dev" ] [ "libsodium13" ];
 
-    deb_ubuntu1410i386 = makeDeb_i686 (diskImageFuns: diskImageFuns.ubuntu1410i386) [] [];
-    deb_ubuntu1410x86_64 = makeDeb_x86_64 (diskImageFuns: diskImageFuns.ubuntu1410x86_64) [] [];
     deb_ubuntu1604i386 = makeDeb_i686 (diskImageFuns: diskImageFuns.ubuntu1604i386) [ "libsodium-dev" ] [ "libsodium18" ];
     deb_ubuntu1604x86_64 = makeDeb_x86_64 (diskImageFuns: diskImageFuns.ubuntu1604x86_64) [ "libsodium-dev" ] [ "libsodium18" ];
-    deb_ubuntu1610i386 = makeDeb_i686 (diskImageFuns: diskImageFuns.ubuntu1610i386) [ "libsodium-dev" ] [ "libsodium18" ];
-    deb_ubuntu1610x86_64 = makeDeb_x86_64 (diskImageFuns: diskImageFuns.ubuntu1610x86_64) [ "libsodium-dev" ] [ "libsodium18" ];
 
 
     # System tests.
     tests.remoteBuilds = (import ./tests/remote-builds.nix rec {
+      inherit nixpkgs;
       nix = build.x86_64-linux; system = "x86_64-linux";
     });
 
     tests.nix-copy-closure = (import ./tests/nix-copy-closure.nix rec {
+      inherit nixpkgs;
       nix = build.x86_64-linux; system = "x86_64-linux";
     });
 
-    tests.setuid = pkgs.lib.genAttrs (pkgs.lib.filter (pkgs.lib.hasSuffix "-linux") systems) (system:
-      import ./tests/setuid.nix rec {
-        nix = build.${system}; inherit system;
-      });
+    tests.setuid = pkgs.lib.genAttrs
+      ["i686-linux" "x86_64-linux"]
+      (system:
+        import ./tests/setuid.nix rec {
+          inherit nixpkgs;
+          nix = build.${system}; inherit system;
+        });
 
     tests.binaryTarball =
-      with import <nixpkgs> { system = "x86_64-linux"; };
+      with import nixpkgs { system = "x86_64-linux"; };
       vmTools.runInLinuxImage (runCommand "nix-binary-tarball-test"
         { diskImage = vmTools.diskImages.ubuntu1204x86_64;
         }
@@ -244,7 +275,7 @@ let
         ''); # */
 
     tests.evalNixpkgs =
-      import <nixpkgs/pkgs/top-level/make-tarball.nix> {
+      import (nixpkgs + "/pkgs/top-level/make-tarball.nix") {
         inherit nixpkgs;
         inherit pkgs;
         nix = build.x86_64-linux;
@@ -257,7 +288,8 @@ let
           export NIX_STATE_DIR=$TMPDIR
           nix-store --init
 
-          nix-instantiate ${nixpkgs}/nixos/release-combined.nix -A tested --dry-run
+          nix-instantiate ${nixpkgs}/nixos/release-combined.nix -A tested --dry-run \
+            --arg nixpkgs '{ outPath = ${nixpkgs}; revCount = 123; shortRev = "abcdefgh"; }'
 
           touch $out
         '';
@@ -275,12 +307,6 @@ let
           binaryTarball.i686-linux
           binaryTarball.x86_64-darwin
           binaryTarball.x86_64-linux
-          deb_debian8i386
-          deb_debian8x86_64
-          deb_ubuntu1604i386
-          deb_ubuntu1604x86_64
-          rpm_fedora25i386
-          rpm_fedora25x86_64
           tests.remoteBuilds
           tests.nix-copy-closure
           tests.binaryTarball
@@ -298,16 +324,17 @@ let
   makeRPM =
     system: diskImageFun: extraPackages:
 
-    with import <nixpkgs> { inherit system; };
+    with import nixpkgs { inherit system; };
 
     releaseTools.rpmBuild rec {
       name = "nix-rpm";
       src = jobs.tarball;
       diskImage = (diskImageFun vmTools.diskImageFuns)
         { extraPackages =
-            [ "sqlite" "sqlite-devel" "bzip2-devel" "emacs" "libcurl-devel" "openssl-devel" "xz-devel" "libseccomp-devel" ]
+            [ "sqlite" "sqlite-devel" "bzip2-devel" "libcurl-devel" "openssl-devel" "xz-devel" "libseccomp-devel" ]
             ++ extraPackages; };
-      memSize = 1024;
+      # At most 2047MB can be simulated in qemu-system-i386
+      memSize = 2047;
       meta.schedulingPriority = 50;
       postRPMInstall = "cd /tmp/rpmout/BUILD/nix-* && make installcheck";
       #enableParallelBuilding = true;
@@ -320,7 +347,7 @@ let
   makeDeb =
     system: diskImageFun: extraPackages: extraDebPackages:
 
-    with import <nixpkgs> { inherit system; };
+    with import nixpkgs { inherit system; };
 
     releaseTools.debBuild {
       name = "nix-deb";

scripts/install-darwin-multi-user.sh

@@ -0,0 +1,144 @@
+#!/usr/bin/env bash
+
+set -eu
+set -o pipefail
+
+readonly PLIST_DEST=/Library/LaunchDaemons/org.nixos.nix-daemon.plist
+
+dsclattr() {
+    /usr/bin/dscl . -read "$1" \
+        | awk "/$2/ { print \$2 }"
+}
+
+poly_validate_assumptions() {
+    if [ "$(uname -s)" != "Darwin" ]; then
+        failure "This script is for use with macOS!"
+    fi
+}
+
+poly_service_installed_check() {
+    [ -e "$PLIST_DEST" ]
+}
+
+poly_service_uninstall_directions() {
+        cat <<EOF
+$1. Delete $PLIST_DEST
+
+  sudo launchctl unload $PLIST_DEST
+  sudo rm $PLIST_DEST
+
+EOF
+}
+
+poly_service_setup_note() {
+    cat <<EOF
+ - load and start a LaunchDaemon (at $PLIST_DEST) for nix-daemon
+
+EOF
+}
+
+poly_configure_nix_daemon_service() {
+    _sudo "to set up the nix-daemon as a LaunchDaemon" \
+          ln -sfn "/nix/var/nix/profiles/default$PLIST_DEST" "$PLIST_DEST"
+
+    _sudo "to load the LaunchDaemon plist for nix-daemon" \
+          launchctl load /Library/LaunchDaemons/org.nixos.nix-daemon.plist
+
+    _sudo "to start the nix-daemon" \
+          launchctl start org.nixos.nix-daemon
+
+}
+
+poly_group_exists() {
+    /usr/bin/dscl . -read "/Groups/$1" > /dev/null 2>&1
+}
+
+poly_group_id_get() {
+    dsclattr "/Groups/$1" "PrimaryGroupID"
+}
+
+poly_create_build_group() {
+    _sudo "Create the Nix build group, $NIX_BUILD_GROUP_NAME" \
+          /usr/sbin/dseditgroup -o create \
+          -r "Nix build group for nix-daemon" \
+          -i "$NIX_BUILD_GROUP_ID" \
+          "$NIX_BUILD_GROUP_NAME" >&2
+}
+
+poly_user_exists() {
+    /usr/bin/dscl . -read "/Users/$1" > /dev/null 2>&1
+}
+
+poly_user_id_get() {
+    dsclattr "/Users/$1" "UniqueID"
+}
+
+poly_user_hidden_get() {
+    dsclattr "/Users/$1" "IsHidden"
+}
+
+poly_user_hidden_set() {
+    _sudo "in order to make $1 a hidden user" \
+          /usr/bin/dscl . -create "/Users/$1" "IsHidden" "1"
+}
+
+poly_user_home_get() {
+    dsclattr "/Users/$1" "NFSHomeDirectory"
+}
+
+poly_user_home_set() {
+    _sudo "in order to give $1 a safe home directory" \
+          /usr/bin/dscl . -create "/Users/$1" "NFSHomeDirectory" "$2"
+}
+
+poly_user_note_get() {
+    dsclattr "/Users/$1" "RealName"
+}
+
+poly_user_note_set() {
+    _sudo "in order to give $username a useful note" \
+          /usr/bin/dscl . -create "/Users/$1" "RealName" "$2"
+}
+
+poly_user_shell_get() {
+    dsclattr "/Users/$1" "UserShell"
+}
+
+poly_user_shell_set() {
+    _sudo "in order to give $1 a safe home directory" \
+          /usr/bin/dscl . -create "/Users/$1" "UserShell" "$2"
+}
+
+poly_user_in_group_check() {
+    username=$1
+    group=$2
+    dseditgroup -o checkmember -m "$username" "$group" > /dev/null 2>&1
+}
+
+poly_user_in_group_set() {
+    username=$1
+    group=$2
+
+    _sudo "Add $username to the $group group"\
+          /usr/sbin/dseditgroup -o edit -t user \
+          -a "$username" "$group"
+}
+
+poly_user_primary_group_get() {
+    dsclattr "/Users/$1" "PrimaryGroupID"
+}
+
+poly_user_primary_group_set() {
+    _sudo "to let the nix daemon use this user for builds (this might seem redundant, but there are two concepts of group membership)" \
+          /usr/bin/dscl . -create "/Users/$1" "PrimaryGroupID" "$2"
+}
+
+poly_create_build_user() {
+    username=$1
+    uid=$2
+    builder_num=$3
+
+    _sudo "Creating the Nix build user (#$builder_num), $username" \
+          /usr/bin/dscl . create "/Users/$username" \
+          UniqueID "${uid}"
+}

scripts/install-multi-user.sh

@@ -0,0 +1,797 @@
+#!/usr/bin/env bash
+
+set -eu
+set -o pipefail
+
+# Sourced from:
+# - https://github.com/LnL7/nix-darwin/blob/8c29d0985d74b4a990238497c47a2542a5616b3c/bootstrap.sh
+# - https://gist.github.com/expipiplus1/e571ce88c608a1e83547c918591b149f/ac504c6c1b96e65505fbda437a28ce563408ecb0
+# - https://github.com/NixOS/nixos-org-configurations/blob/a122f418797713d519aadf02e677fce0dc1cb446/delft/scripts/nix-mac-installer.sh
+# - https://github.com/matthewbauer/macNixOS/blob/f6045394f9153edea417be90c216788e754feaba/install-macNixOS.sh
+# - https://gist.github.com/LnL7/9717bd6cdcb30b086fd7f2093e5f8494/86b26f852ce563e973acd30f796a9a416248c34a
+#
+# however tracking which bits came from which would be impossible.
+
+readonly ESC='\033[0m'
+readonly BOLD='\033[38;1m'
+readonly BLUE='\033[38;34m'
+readonly BLUE_UL='\033[38;4;34m'
+readonly GREEN='\033[38;32m'
+readonly GREEN_UL='\033[38;4;32m'
+readonly RED='\033[38;31m'
+readonly RED_UL='\033[38;4;31m'
+readonly YELLOW='\033[38;33m'
+readonly YELLOW_UL='\033[38;4;33m'
+
+readonly NIX_USER_COUNT="32"
+readonly NIX_BUILD_GROUP_ID="30000"
+readonly NIX_BUILD_GROUP_NAME="nixbld"
+readonly NIX_FIRST_BUILD_UID="30001"
+# Please don't change this. We don't support it, because the
+# default shell profile that comes with Nix doesn't support it.
+readonly NIX_ROOT="/nix"
+
+readonly PROFILE_TARGETS=("/etc/bashrc" "/etc/profile.d/nix.sh" "/etc/zshrc")
+readonly PROFILE_BACKUP_SUFFIX=".backup-before-nix"
+readonly PROFILE_NIX_FILE="$NIX_ROOT/var/nix/profiles/default/etc/profile.d/nix-daemon.sh"
+
+readonly NIX_INSTALLED_NIX="@nix@"
+readonly NIX_INSTALLED_CACERT="@cacert@"
+readonly EXTRACTED_NIX_PATH="$(dirname "$0")"
+
+readonly ROOT_HOME=$(echo ~root)
+
+if [ -t 0 ]; then
+    readonly IS_HEADLESS='no'
+else
+    readonly IS_HEADLESS='yes'
+fi
+
+headless() {
+    if [ "$IS_HEADLESS" = "yes" ]; then
+        return 0
+    else
+        return 1
+    fi
+}
+
+contactme() {
+    echo "We'd love to help if you need it."
+    echo ""
+    echo "If you can, open an issue at https://github.com/nixos/nix/issues"
+    echo ""
+    echo "Or feel free to contact the team,"
+    echo " - on IRC #nixos on irc.freenode.net"
+    echo " - on twitter @nixos_org"
+}
+
+uninstall_directions() {
+    subheader "Uninstalling nix:"
+    local step=0
+
+    if poly_service_installed_check; then
+        step=$((step + 1))
+        poly_service_uninstall_directions "$step"
+    fi
+
+    for profile_target in "${PROFILE_TARGETS[@]}"; do
+        if [ -e "$profile_target" ] && [ -e "$profile_target$PROFILE_BACKUP_SUFFIX" ]; then
+            step=$((step + 1))
+            cat <<EOF
+$step. Restore $profile_target$PROFILE_BACKUP_SUFFIX back to $profile_target
+
+  sudo mv $profile_target$PROFILE_BACKUP_SUFFIX $profile_target
+
+(after this one, you may need to re-open any terminals that were
+opened while it existed.)
+
+EOF
+        fi
+    done
+
+    step=$((step + 1))
+    cat <<EOF
+$step. Delete the files Nix added to your system:
+
+  sudo rm -rf /etc/nix $NIX_ROOT $ROOT_HOME/.nix-profile $ROOT_HOME/.nix-defexpr $ROOT_HOME/.nix-channels $HOME/.nix-profile $HOME/.nix-defexpr $HOME/.nix-channels
+
+and that is it.
+
+EOF
+
+}
+
+nix_user_for_core() {
+    printf "nixbld%d" "$1"
+}
+
+nix_uid_for_core() {
+    echo $((NIX_FIRST_BUILD_UID + $1 - 1))
+}
+
+_textout() {
+    echo -en "$1"
+    shift
+    if [ "$*" = "" ]; then
+        cat
+    else
+        echo "$@"
+    fi
+    echo -en "$ESC"
+}
+
+header() {
+    follow="---------------------------------------------------------"
+    header=$(echo "---- $* $follow$follow$follow" | head -c 80)
+    echo ""
+    _textout "$BLUE" "$header"
+}
+
+warningheader() {
+    follow="---------------------------------------------------------"
+    header=$(echo "---- $* $follow$follow$follow" | head -c 80)
+    echo ""
+    _textout "$RED" "$header"
+}
+
+subheader() {
+    echo ""
+    _textout "$BLUE_UL" "$*"
+}
+
+row() {
+    printf "$BOLD%s$ESC:\\t%s\\n" "$1" "$2"
+}
+
+task() {
+    echo ""
+    ok "~~> $1"
+}
+
+bold() {
+    echo "$BOLD$*$ESC"
+}
+
+ok() {
+    _textout "$GREEN" "$@"
+}
+
+warning() {
+    warningheader "warning!"
+    cat
+    echo ""
+}
+
+failure() {
+    header "oh no!"
+    _textout "$RED" "$@"
+    echo ""
+    _textout "$RED" "$(contactme)"
+    trap finish_cleanup EXIT
+    exit 1
+}
+
+ui_confirm() {
+    _textout "$GREEN$GREEN_UL" "$1"
+
+    if headless; then
+        echo "No TTY, assuming you would say yes :)"
+        return 0
+    fi
+
+    local prompt="[y/n] "
+    echo -n "$prompt"
+    while read -r y; do
+        if [ "$y" = "y" ]; then
+            echo ""
+            return 0
+        elif [ "$y" = "n" ]; then
+            echo ""
+            return 1
+        else
+            _textout "$RED" "Sorry, I didn't understand. I can only understand answers of y or n"
+            echo -n "$prompt"
+        fi
+    done
+    echo ""
+    return 1
+}
+
+__sudo() {
+    local expl="$1"
+    local cmd="$2"
+    shift
+    header "sudo execution"
+
+    echo "I am executing:"
+    echo ""
+    printf "    $ sudo %s\\n" "$cmd"
+    echo ""
+    echo "$expl"
+    echo ""
+
+    return 0
+}
+
+_sudo() {
+    local expl="$1"
+    shift
+    if ! headless; then
+        __sudo "$expl" "$*"
+    fi
+    sudo "$@"
+}
+
+
+readonly SCRATCH=$(mktemp -d -t tmp.XXXXXXXXXX)
+function finish_cleanup {
+    rm -rf "$SCRATCH"
+}
+
+function finish_fail {
+    finish_cleanup
+
+    failure <<EOF
+Jeeze, something went wrong. If you can take all the output and open
+an issue, we'd love to fix the problem so nobody else has this issue.
+
+:(
+EOF
+}
+trap finish_fail EXIT
+
+function finish_success {
+    finish_cleanup
+
+    ok "Alright! We're done!"
+    cat <<EOF
+
+Before Nix will work in your existing shells, you'll need to close
+them and open them again. Other than that, you should be ready to go.
+
+Try it! Open a new terminal, and type:
+
+  $ nix-shell -p nix-info --run "nix-info -m"
+
+Thank you for using this installer. If you have any feedback, don't
+hesitate:
+
+$(contactme)
+EOF
+}
+
+
+validate_starting_assumptions() {
+    poly_validate_assumptions
+
+    if [ $EUID -eq 0 ]; then
+        failure <<EOF
+Please do not run this script with root privileges. We will call sudo
+when we need to.
+EOF
+    fi
+
+    if type nix-env 2> /dev/null >&2; then
+        failure <<EOF
+Nix already appears to be installed, and this tool assumes it is
+_not_ yet installed.
+
+$(uninstall_directions)
+EOF
+    fi
+
+    if [ "${NIX_REMOTE:-}" != "" ]; then
+        failure <<EOF
+For some reason, \$NIX_REMOTE is set. It really should not be set
+before this installer runs, and it hints that Nix is currently
+installed. Please delete the old Nix installation and start again.
+
+Note: You might need to close your shell window and open a new shell
+to clear the variable.
+EOF
+    fi
+
+    if echo "${SSL_CERT_FILE:-}" | grep -qE "(nix/var/nix|nix-profile)"; then
+        failure <<EOF
+It looks like \$SSL_CERT_FILE is set to a path that used to be part of
+the old Nix installation. Please unset that variable and try again:
+
+  $ unset SSL_CERT_FILE
+
+EOF
+    fi
+
+    for file in ~/.bash_profile ~/.bash_login ~/.profile ~/.zshenv ~/.zprofile ~/.zshrc ~/.zlogin; do
+        if [ -f "$file" ]; then
+            if grep -l "^[^#].*.nix-profile" "$file"; then
+                failure <<EOF
+I found a reference to a ".nix-profile" in $file.
+This has a high chance of breaking a new nix installation. It was most
+likely put there by a previous Nix installer.
+
+Please remove this reference and try running this again. You should
+also look for similar references in:
+
+ - ~/.bash_profile
+ - ~/.bash_login
+ - ~/.profile
+
+or other shell init files that you may have.
+
+$(uninstall_directions)
+EOF
+            fi
+        fi
+    done
+
+    if [ -d /nix ]; then
+        failure <<EOF
+There are some relics of a previous installation of Nix at /nix, and
+this scripts assumes Nix is _not_ yet installed. Please delete the old
+Nix installation and start again.
+
+$(uninstall_directions)
+EOF
+    fi
+
+    if [ -d /etc/nix ]; then
+        failure <<EOF
+There are some relics of a previous installation of Nix at /etc/nix, and
+this scripts assumes Nix is _not_ yet installed. Please delete the old
+Nix installation and start again.
+
+$(uninstall_directions)
+EOF
+    fi
+
+    for profile_target in "${PROFILE_TARGETS[@]}"; do
+        if [ -e "$profile_target$PROFILE_BACKUP_SUFFIX" ]; then
+        failure <<EOF
+When this script runs, it backs up the current $profile_target to
+$profile_target$PROFILE_BACKUP_SUFFIX. This backup file already exists, though.
+
+Please follow these instructions to clean up the old backup file:
+
+1. Copy $profile_target and $profile_target$PROFILE_BACKUP_SUFFIX to another place, just
+in case.
+
+2. Take care to make sure that $profile_target$PROFILE_BACKUP_SUFFIX doesn't look like
+it has anything nix-related in it. If it does, something is probably
+quite wrong. Please open an issue or get in touch immediately.
+
+3. Take care to make sure that $profile_target doesn't look like it has
+anything nix-related in it. If it does, and $profile_target _did not_,
+run:
+
+  $ /usr/bin/sudo /bin/mv $profile_target$PROFILE_BACKUP_SUFFIX $profile_target
+
+and try again.
+EOF
+        fi
+
+        if [ -e "$profile_target" ] && grep -qi "nix" "$profile_target"; then
+            failure <<EOF
+It looks like $profile_target already has some Nix configuration in
+there. There should be no reason to run this again. If you're having
+trouble, please open an issue.
+EOF
+        fi
+    done
+
+    danger_paths=("$ROOT_HOME/.nix-defexpr" "$ROOT_HOME/.nix-channels" "$ROOT_HOME/.nix-profile")
+    for danger_path in "${danger_paths[@]}"; do
+        if _sudo "making sure that $danger_path doesn't exist" \
+           test -e "$danger_path"; then
+            failure <<EOF
+I found a file at $danger_path, which is a relic of a previous
+installation. You must first delete this file before continuing.
+
+$(uninstall_directions)
+EOF
+        fi
+    done
+}
+
+setup_report() {
+    header "Nix config report"
+    row "        Temp Dir" "$SCRATCH"
+    row "        Nix Root" "$NIX_ROOT"
+    row "     Build Users" "$NIX_USER_COUNT"
+    row "  Build Group ID" "$NIX_BUILD_GROUP_ID"
+    row "Build Group Name" "$NIX_BUILD_GROUP_NAME"
+    if [ "${ALLOW_PREEXISTING_INSTALLATION:-}" != "" ]; then
+        row "Preexisting Install" "Allowed"
+    fi
+
+    subheader "build users:"
+
+    row "    Username" "UID"
+    for i in $(seq 1 "$NIX_USER_COUNT"); do
+        row "     $(nix_user_for_core "$i")" "$(nix_uid_for_core "$i")"
+    done
+    echo ""
+}
+
+create_build_group() {
+    local primary_group_id
+
+    task "Setting up the build group $NIX_BUILD_GROUP_NAME"
+    if ! poly_group_exists "$NIX_BUILD_GROUP_NAME"; then
+        poly_create_build_group
+        row "            Created" "Yes"
+    else
+        primary_group_id=$(poly_group_id_get "$NIX_BUILD_GROUP_NAME")
+        if [ "$primary_group_id" -ne "$NIX_BUILD_GROUP_ID" ]; then
+            failure <<EOF
+It seems the build group $NIX_BUILD_GROUP_NAME already exists, but
+with the UID $primary_group_id. This script can't really handle
+that right now, so I'm going to give up.
+
+You can fix this by editing this script and changing the
+NIX_BUILD_GROUP_ID variable near the top to from $NIX_BUILD_GROUP_ID
+to $primary_group_id and re-run.
+EOF
+        else
+            row "            Exists" "Yes"
+        fi
+    fi
+}
+
+create_build_user_for_core() {
+    local coreid
+    local username
+    local uid
+
+    coreid="$1"
+    username=$(nix_user_for_core "$coreid")
+    uid=$(nix_uid_for_core "$coreid")
+
+    task "Setting up the build user $username"
+
+    if ! poly_user_exists "$username"; then
+        poly_create_build_user "$username" "$uid" "$coreid"
+        row "           Created" "Yes"
+    else
+        actual_uid=$(poly_user_id_get "$username")
+        if [ "$actual_uid" != "$uid" ]; then
+            failure <<EOF
+It seems the build user $username already exists, but with the UID
+with the UID '$actual_uid'. This script can't really handle that right
+now, so I'm going to give up.
+
+If you already created the users and you know they start from
+$actual_uid and go up from there, you can edit this script and change
+NIX_FIRST_BUILD_UID near the top of the file to $actual_uid and try
+again.
+EOF
+        else
+            row "            Exists" "Yes"
+        fi
+    fi
+
+    if [ "$(poly_user_hidden_get "$username")" = "1" ]; then
+        row "            Hidden" "Yes"
+    else
+        poly_user_hidden_set "$username"
+        row "            Hidden" "Yes"
+    fi
+
+    if [ "$(poly_user_home_get "$username")" = "/var/empty" ]; then
+        row "    Home Directory" "/var/empty"
+    else
+        poly_user_home_set "$username" "/var/empty"
+        row "    Home Directory" "/var/empty"
+    fi
+
+    # We use grep instead of an equality check because it is difficult
+    # to extract _just_ the user's note, instead it is prefixed with
+    # some plist junk. This was causing the user note to always be set,
+    # even if there was no reason for it.
+    if ! poly_user_note_get "$username" | grep -q "Nix build user $coreid"; then
+        row "              Note" "Nix build user $coreid"
+    else
+        poly_user_note_set "$username" "Nix build user $coreid"
+        row "              Note" "Nix build user $coreid"
+    fi
+
+    if [ "$(poly_user_shell_get "$username")" = "/sbin/nologin" ]; then
+        row "   Logins Disabled" "Yes"
+    else
+        poly_user_shell_set "$username" "/sbin/nologin"
+        row "   Logins Disabled" "Yes"
+    fi
+
+    if poly_user_in_group_check "$username" "$NIX_BUILD_GROUP_NAME"; then
+        row "  Member of $NIX_BUILD_GROUP_NAME" "Yes"
+    else
+        poly_user_in_group_set "$username" "$NIX_BUILD_GROUP_NAME"
+        row "  Member of $NIX_BUILD_GROUP_NAME" "Yes"
+    fi
+
+    if [ "$(poly_user_primary_group_get "$username")" = "$NIX_BUILD_GROUP_ID" ]; then
+        row "    PrimaryGroupID" "$NIX_BUILD_GROUP_ID"
+    else
+        poly_user_primary_group_set "$username" "$NIX_BUILD_GROUP_ID"
+        row "    PrimaryGroupID" "$NIX_BUILD_GROUP_ID"
+    fi
+}
+
+create_build_users() {
+    for i in $(seq 1 "$NIX_USER_COUNT"); do
+        create_build_user_for_core "$i"
+    done
+}
+
+create_directories() {
+    _sudo "to make the basic directory structure of Nix (part 1)" \
+          mkdir -pv -m 0755 /nix /nix/var /nix/var/log /nix/var/log/nix /nix/var/log/nix/drvs /nix/var/nix{,/db,/gcroots,/profiles,/temproots,/userpool}
+
+    _sudo "to make the basic directory structure of Nix (part 2)" \
+          mkdir -pv -m 1777 /nix/var/nix/{gcroots,profiles}/per-user
+
+    _sudo "to make the basic directory structure of Nix (part 3)" \
+          mkdir -pv -m 1775 /nix/store
+
+    _sudo "to make the basic directory structure of Nix (part 4)" \
+          chgrp "$NIX_BUILD_GROUP_NAME" /nix/store
+
+    _sudo "to set up the root user's profile (part 1)" \
+          mkdir -pv -m 0755 /nix/var/nix/profiles/per-user/root
+
+    _sudo "to set up the root user's profile (part 2)" \
+          mkdir -pv -m 0700 "$ROOT_HOME/.nix-defexpr"
+
+    _sudo "to place the default nix daemon configuration (part 1)" \
+          mkdir -pv -m 0555 /etc/nix
+}
+
+place_channel_configuration() {
+    echo "https://nixos.org/channels/nixpkgs-unstable nixpkgs" > "$SCRATCH/.nix-channels"
+    _sudo "to set up the default system channel (part 1)" \
+          install -m 0664 "$SCRATCH/.nix-channels" "$ROOT_HOME/.nix-channels"
+}
+
+welcome_to_nix() {
+    ok "Welcome to the Multi-User Nix Installation"
+
+    cat <<EOF
+
+This installation tool will set up your computer with the Nix package
+manager. This will happen in a few stages:
+
+1. Make sure your computer doesn't already have Nix. If it does, I
+   will show you instructions on how to clean up your old one.
+
+2. Show you what we are going to install and where. Then we will ask
+   if you are ready to continue.
+
+3. Create the system users and groups that the Nix daemon uses to run
+   builds.
+
+4. Perform the basic installation of the Nix files daemon.
+
+5. Configure your shell to import special Nix Profile files, so you
+   can use Nix.
+
+6. Start the Nix daemon.
+
+EOF
+
+    if ui_confirm "Would you like to see a more detailed list of what we will do?"; then
+        cat <<EOF
+
+We will:
+
+ - make sure your computer doesn't already have Nix files
+   (if it does, I  will tell you how to clean them up.)
+ - create local users (see the list above for the users we'll make)
+ - create a local group ($NIX_BUILD_GROUP_NAME)
+ - install Nix in to $NIX_ROOT
+ - create a configuration file in /etc/nix
+ - set up the "default profile" by creating some Nix-related files in
+   $ROOT_HOME
+EOF
+        for profile_target in "${PROFILE_TARGETS[@]}"; do
+            if [ -e "$profile_target" ]; then
+                cat <<EOF
+ - back up $profile_target to $profile_target$PROFILE_BACKUP_SUFFIX
+ - update $profile_target to include some Nix configuration
+EOF
+            fi
+        done
+        poly_service_setup_note
+        if ! ui_confirm "Ready to continue?"; then
+            failure <<EOF
+Okay, maybe you would like to talk to the team.
+EOF
+        fi
+    fi
+}
+
+chat_about_sudo() {
+    header "let's talk about sudo"
+
+    if headless; then
+        cat <<EOF
+This script is going to call sudo a lot. Normally, it would show you
+exactly what commands it is running and why. However, the script is
+run in a headless fashion, like this:
+
+  $ curl https://nixos.org/nix/install | sh
+
+or maybe in a CI pipeline. Because of that, we're going to skip the
+verbose output in the interest of brevity.
+
+If you would like to
+see the output, try like this:
+
+  $ curl -o install-nix https://nixos.org/nix/install
+  $ sh ./install-nix
+
+EOF
+        return 0
+    fi
+
+    cat <<EOF
+This script is going to call sudo a lot. Every time we do, it'll
+output exactly what it'll do, and why.
+
+Just like this:
+EOF
+
+    __sudo "to demonstrate how our sudo prompts look" \
+           echo "this is a sudo prompt"
+
+    cat <<EOF
+
+This might look scary, but everything can be undone by running just a
+few commands. We used to ask you to confirm each time sudo ran, but it
+was too many times. Instead, I'll just ask you this one time:
+
+EOF
+    if ui_confirm "Can we use sudo?"; then
+        ok "Yay! Thanks! Let's get going!"
+    else
+        failure <<EOF
+That is okay, but we can't install.
+EOF
+    fi
+}
+
+install_from_extracted_nix() {
+    (
+        cd "$EXTRACTED_NIX_PATH"
+
+        _sudo "to copy the basic Nix files to the new store at $NIX_ROOT/store" \
+              rsync -rlpt ./store/* "$NIX_ROOT/store/"
+
+        if [ -d "$NIX_INSTALLED_NIX" ]; then
+            echo "      Alright! We have our first nix at $NIX_INSTALLED_NIX"
+        else
+            failure <<EOF
+Something went wrong, and I didn't find Nix installed at
+$NIX_INSTALLED_NIX.
+EOF
+        fi
+
+        _sudo "to initialize the Nix Database" \
+              $NIX_INSTALLED_NIX/bin/nix-store --init
+
+        cat ./.reginfo \
+            | _sudo "to load data for the first time in to the Nix Database" \
+                   "$NIX_INSTALLED_NIX/bin/nix-store" --load-db
+
+        echo "      Just finished getting the nix database ready."
+    )
+}
+
+shell_source_lines() {
+    cat <<EOF
+
+# Nix
+if [ -e '$PROFILE_NIX_FILE' ]; then
+  . '$PROFILE_NIX_FILE'
+fi
+# End Nix
+
+EOF
+}
+
+configure_shell_profile() {
+    # If there is an /etc/profile.d directory, we want to ensure there
+    # is a nix.sh within it, so we can use the following loop to add
+    # the source lines to it. Note that I'm _not_ adding the source
+    # lines here, because we want to be using the regular machinery.
+    #
+    # If we go around that machinery, it becomes more complicated and
+    # adds complications to the uninstall instruction generator and
+    # old instruction sniffer as well.
+    if [ -d /etc/profile.d ]; then
+        _sudo "create a stub /etc/profile.d/nix.sh which will be updated" \
+              touch /etc/profile.d/nix.sh
+    fi
+
+    for profile_target in "${PROFILE_TARGETS[@]}"; do
+        if [ -e "$profile_target" ]; then
+            _sudo "to back up your current $profile_target to $profile_target$PROFILE_BACKUP_SUFFIX" \
+                  cp "$profile_target" "$profile_target$PROFILE_BACKUP_SUFFIX"
+
+            shell_source_lines \
+                | _sudo "extend your $profile_target with nix-daemon settings" \
+                        tee -a "$profile_target"
+        fi
+    done
+}
+
+setup_default_profile() {
+    _sudo "to installing a bootstrapping Nix in to the default Profile" \
+          HOME="$ROOT_HOME" "$NIX_INSTALLED_NIX/bin/nix-env" -i "$NIX_INSTALLED_NIX"
+
+    _sudo "to installing a bootstrapping SSL certificate just for Nix in to the default Profile" \
+          HOME="$ROOT_HOME" "$NIX_INSTALLED_NIX/bin/nix-env" -i "$NIX_INSTALLED_CACERT"
+
+    _sudo "to update the default channel in the default profile" \
+          HOME="$ROOT_HOME" NIX_SSL_CERT_FILE=/nix/var/nix/profiles/default/etc/ssl/certs/ca-bundle.crt "$NIX_INSTALLED_NIX/bin/nix-channel" --update nixpkgs
+}
+
+
+place_nix_configuration() {
+    cat <<EOF > "$SCRATCH/nix.conf"
+build-users-group = $NIX_BUILD_GROUP_NAME
+
+max-jobs = $NIX_USER_COUNT
+cores = 1
+sandbox = false
+EOF
+    _sudo "to place the default nix daemon configuration (part 2)" \
+          install -m 0664 "$SCRATCH/nix.conf" /etc/nix/nix.conf
+}
+
+main() {
+    if [ "$(uname -s)" = "Darwin" ]; then
+        # shellcheck source=./install-darwin-multi-user.sh
+        . "$EXTRACTED_NIX_PATH/install-darwin-multi-user.sh"
+    elif [ "$(uname -s)" = "Linux" ] && [ -e /run/systemd/system ]; then
+        # shellcheck source=./install-systemd-multi-user.sh
+        . "$EXTRACTED_NIX_PATH/install-systemd-multi-user.sh"
+    else
+        failure "Sorry, I don't know what to do on $(uname)"
+    fi
+
+    welcome_to_nix
+    chat_about_sudo
+
+    if [ "${ALLOW_PREEXISTING_INSTALLATION:-}" = "" ]; then
+        validate_starting_assumptions
+    fi
+
+    setup_report
+
+    if ! ui_confirm "Ready to continue?"; then
+        ok "Alright, no changes have been made :)"
+        contactme
+        trap finish_cleanup EXIT
+        exit 1
+    fi
+
+    create_build_group
+    create_build_users
+    create_directories
+    place_channel_configuration
+    install_from_extracted_nix
+
+    configure_shell_profile
+
+    set +eu
+    . /etc/profile
+    set -eu
+
+    setup_default_profile
+    place_nix_configuration
+    poly_configure_nix_daemon_service
+
+    trap finish_success EXIT
+}
+
+
+main

scripts/install-nix-from-closure.sh

@@ -8,15 +8,8 @@ nix="@nix@"
 cacert="@cacert@"
 
 
-# macOS support for 10.10 or higher
-if [[ "$(uname -s)" = "Darwin" && $(($(sw_vers -productVersion | cut -d '.' -f 2))) -lt 10 ]]; then
-    echo "$0: macOS $(sw_vers -productVersion) is not supported, upgrade to 10.10 or higher"
-    exit 1
-fi
-
 if ! [ -e "$self/.reginfo" ]; then
     echo "$0: incomplete installer (.reginfo is missing)" >&2
-    exit 1
 fi
 
 if [ -z "$USER" ]; then
@@ -24,6 +17,55 @@ if [ -z "$USER" ]; then
     exit 1
 fi
 
+if [ -z "$HOME" ]; then
+    echo "$0: \$HOME is not set" >&2
+    exit 1
+fi
+
+# macOS support for 10.10 or higher
+if [ "$(uname -s)" = "Darwin" ]; then
+    if [ $(($(sw_vers -productVersion | cut -d '.' -f 2))) -lt 10 ]; then
+        echo "$0: macOS $(sw_vers -productVersion) is not supported, upgrade to 10.10 or higher"
+        exit 1
+    fi
+fi
+
+# Determine if we should punt to the single-user installer or not
+if [ "$(uname -s)" = "Darwin" ]; then
+    INSTALL_MODE=daemon
+elif [ "$(uname -s)" = "Linux" ] && [ -e /run/systemd/system ]; then
+    INSTALL_MODE=no-daemon
+else
+    INSTALL_MODE=no-daemon
+fi
+
+# Trivially handle the --daemon / --no-daemon options
+if [ "x${1:-}" = "x--no-daemon" ]; then
+    INSTALL_MODE=no-daemon
+elif [ "x${1:-}" = "x--daemon" ]; then
+    INSTALL_MODE=daemon
+elif [ "x${1:-}" != "x" ]; then
+    (
+        echo "Nix Installer [--daemon|--no-daemon]"
+        echo ""
+        echo " --daemon:    Force the installer to use the Daemon"
+        echo "              based installer, even though it may not"
+        echo "              work."
+        echo ""
+        echo " --no-daemon: Force a no-daemon, single-user"
+        echo "              installation even when the preferred"
+        echo "              method is with the daemon."
+        echo ""
+    ) >&2
+    exit
+fi
+
+if [ "$INSTALL_MODE" = "daemon" ]; then
+    printf '\e[1;31mSwitching to the Daemon-based Installer\e[0m\n'
+    exec "$self/install-multi-user"
+    exit 0
+fi
+
 if [ "$(id -u)" -eq 0 ]; then
     printf '\e[1;31mwarning: installing Nix as root is not supported by this script!\e[0m\n'
 fi
@@ -34,13 +76,13 @@ if ! [ -e $dest ]; then
     cmd="mkdir -m 0755 $dest && chown $USER $dest"
     echo "directory $dest does not exist; creating it by running '$cmd' using sudo" >&2
     if ! sudo sh -c "$cmd"; then
-        echo "$0: please manually run ‘$cmd’ as root to create $dest" >&2
+        echo "$0: please manually run '$cmd' as root to create $dest" >&2
         exit 1
     fi
 fi
 
 if ! [ -w $dest ]; then
-    echo "$0: directory $dest exists, but is not writable by you. This could indicate that another user has already performed a single-user installation of Nix on this system. If you wish to enable multi-user support see http://nixos.org/nix/manual/#ssec-multi-user. If you wish to continue with a single-user install for $USER please run ‘chown -R $USER $dest’ as root." >&2
+    echo "$0: directory $dest exists, but is not writable by you. This could indicate that another user has already performed a single-user installation of Nix on this system. If you wish to enable multi-user support see http://nixos.org/nix/manual/#ssec-multi-user. If you wish to continue with a single-user install for $USER please run 'chown -R $USER $dest' as root." >&2
     exit 1
 fi
 

scripts/install-systemd-multi-user.sh

@@ -0,0 +1,154 @@
+#!/usr/bin/env bash
+
+set -eu
+set -o pipefail
+
+readonly SERVICE_SRC=/lib/systemd/system/nix-daemon.service
+readonly SERVICE_DEST=/etc/systemd/system/nix-daemon.service
+
+readonly SOCKET_SRC=/lib/systemd/system/nix-daemon.socket
+readonly SOCKET_DEST=/etc/systemd/system/nix-daemon.socket
+
+poly_validate_assumptions() {
+    if [ "$(uname -s)" != "Linux" ]; then
+        failure "This script is for use with Linux!"
+    fi
+}
+
+poly_service_installed_check() {
+    [ "$(systemctl is-enabled nix-daemon.service)" = "linked" ] \
+        || [ "$(systemctl is-enabled nix-daemon.socket)" = "enabled" ]
+}
+
+poly_service_uninstall_directions() {
+        cat <<EOF
+$1. Delete the systemd service and socket units
+
+  sudo systemctl stop nix-daemon.socket
+  sudo systemctl stop nix-daemon.service
+  sudo systemctl disable nix-daemon.socket
+  sudo systemctl disable nix-daemon.service
+  sudo systemctl daemon-reload
+EOF
+}
+
+poly_service_setup_note() {
+    cat <<EOF
+ - load and start a service (at $SERVICE_DEST
+   and $SOCKET_DEST) for nix-daemon
+
+EOF
+}
+
+poly_configure_nix_daemon_service() {
+    _sudo "to set up the nix-daemon service" \
+          systemctl link "/nix/var/nix/profiles/default$SERVICE_SRC"
+
+    _sudo "to set up the nix-daemon socket service" \
+          systemctl enable "/nix/var/nix/profiles/default$SOCKET_SRC"
+
+    _sudo "to load the systemd unit for nix-daemon" \
+          systemctl daemon-reload
+
+    _sudo "to start the nix-daemon.socket" \
+          systemctl start nix-daemon.socket
+
+    _sudo "to start the nix-daemon.service" \
+          systemctl start nix-daemon.service
+
+}
+
+poly_group_exists() {
+    getent group "$1" > /dev/null 2>&1
+}
+
+poly_group_id_get() {
+    getent group "$1" | cut -d: -f3
+}
+
+poly_create_build_group() {
+    _sudo "Create the Nix build group, $NIX_BUILD_GROUP_NAME" \
+          groupadd -g "$NIX_BUILD_GROUP_ID" --system \
+          "$NIX_BUILD_GROUP_NAME" >&2
+}
+
+poly_user_exists() {
+    getent passwd "$1" > /dev/null 2>&1
+}
+
+poly_user_id_get() {
+    getent passwd "$1" | cut -d: -f3
+}
+
+poly_user_hidden_get() {
+    echo "1"
+}
+
+poly_user_hidden_set() {
+    true
+}
+
+poly_user_home_get() {
+    getent passwd "$1" | cut -d: -f6
+}
+
+poly_user_home_set() {
+    _sudo "in order to give $1 a safe home directory" \
+          usermod --home "$2" "$1"
+}
+
+poly_user_note_get() {
+    getent passwd "$1" | cut -d: -f5
+}
+
+poly_user_note_set() {
+    _sudo "in order to give $1 a useful comment" \
+          usermod --comment "$2" "$1"
+}
+
+poly_user_shell_get() {
+    getent passwd "$1" | cut -d: -f7
+}
+
+poly_user_shell_set() {
+    _sudo "in order to prevent $1 from logging in" \
+          usermod --shell "$2" "$1"
+}
+
+poly_user_in_group_check() {
+    groups "$1" | grep -q "$2" > /dev/null 2>&1
+}
+
+poly_user_in_group_set() {
+    _sudo "Add $1 to the $2 group"\
+          usermod --append --groups "$2" "$1"
+}
+
+poly_user_primary_group_get() {
+    getent passwd "$1" | cut -d: -f4
+}
+
+poly_user_primary_group_set() {
+    _sudo "to let the nix daemon use this user for builds (this might seem redundant, but there are two concepts of group membership)" \
+          usermod --gid "$2" "$1"
+
+}
+
+poly_create_build_user() {
+    username=$1
+    uid=$2
+    builder_num=$3
+
+    _sudo "Creating the Nix build user, $username" \
+          useradd \
+          --home-dir /var/empty \
+          --comment "Nix build user $builder_num" \
+          --gid "$NIX_BUILD_GROUP_ID" \
+          --groups "$NIX_BUILD_GROUP_NAME" \
+          --no-user-group \
+          --system \
+          --shell /sbin/nologin \
+          --uid "$uid" \
+          --password "!" \
+          "$username"
+}

scripts/local.mk

@@ -8,5 +8,6 @@ noinst-scripts += $(nix_noinst_scripts)
 profiledir = $(sysconfdir)/profile.d
 
 $(eval $(call install-file-as, $(d)/nix-profile.sh, $(profiledir)/nix.sh, 0644))
+$(eval $(call install-file-as, $(d)/nix-profile-daemon.sh, $(profiledir)/nix-daemon.sh, 0644))
 
 clean-files += $(nix_noinst_scripts)

scripts/nix-profile-daemon.sh.in

@@ -0,0 +1,54 @@
+# Only execute this file once per shell.
+if [ -n "$__ETC_PROFILE_NIX_SOURCED" ]; then return; fi
+__ETC_PROFILE_NIX_SOURCED=1
+
+# Set up secure multi-user builds: non-root users build through the
+# Nix daemon.
+if [ "$USER" != root -o ! -w @localstatedir@/nix/db ]; then
+    export NIX_REMOTE=daemon
+fi
+
+export NIX_USER_PROFILE_DIR="@localstatedir@/nix/profiles/per-user/$USER"
+export NIX_PROFILES="@localstatedir@/nix/profiles/default $HOME/.nix-profile"
+
+# Set up the per-user profile.
+mkdir -m 0755 -p $NIX_USER_PROFILE_DIR
+if ! test -O "$NIX_USER_PROFILE_DIR"; then
+    echo "WARNING: bad ownership on $NIX_USER_PROFILE_DIR" >&2
+fi
+
+if test -w $HOME; then
+  if ! test -L $HOME/.nix-profile; then
+      if test "$USER" != root; then
+          ln -s $NIX_USER_PROFILE_DIR/profile $HOME/.nix-profile
+      else
+          # Root installs in the system-wide profile by default.
+          ln -s @localstatedir@/nix/profiles/default $HOME/.nix-profile
+      fi
+  fi
+
+  # Subscribe the root user to the NixOS channel by default.
+  if [ "$USER" = root -a ! -e $HOME/.nix-channels ]; then
+      echo "https://nixos.org/channels/nixpkgs-unstable nixpkgs" > $HOME/.nix-channels
+  fi
+
+  # Create the per-user garbage collector roots directory.
+  NIX_USER_GCROOTS_DIR=@localstatedir@/nix/gcroots/per-user/$USER
+  mkdir -m 0755 -p $NIX_USER_GCROOTS_DIR
+  if ! test -O "$NIX_USER_GCROOTS_DIR"; then
+      echo "WARNING: bad ownership on $NIX_USER_GCROOTS_DIR" >&2
+  fi
+
+  # Set up a default Nix expression from which to install stuff.
+  if [ ! -e $HOME/.nix-defexpr -o -L $HOME/.nix-defexpr ]; then
+      rm -f $HOME/.nix-defexpr
+      mkdir -p $HOME/.nix-defexpr
+      if [ "$USER" != root ]; then
+          ln -s @localstatedir@/nix/profiles/per-user/root/channels $HOME/.nix-defexpr/channels_root
+      fi
+  fi
+fi
+
+export NIX_SSL_CERT_FILE="@localstatedir@/nix/profiles/default/etc/ssl/certs/ca-bundle.crt"
+export NIX_PATH="@localstatedir@/nix/profiles/per-user/root/channels"
+export PATH="$HOME/.nix-profile/bin:$HOME/.nix-profile/lib/kde4/libexec:@localstatedir@/nix/profiles/default/bin:@localstatedir@/nix/profiles/default:@localstatedir@/nix/profiles/default/lib/kde4/libexec:$PATH"

scripts/nix-profile.sh.in

@@ -60,12 +60,6 @@ if [ -n "$HOME" ] && [ -n "$USER" ]; then
     # This part should be kept in sync with nixpkgs:nixos/modules/programs/environment.nix
     NIX_PROFILES="@localstatedir@/nix/profiles/default $NIX_USER_PROFILE_DIR"
 
-    for i in $NIX_PROFILES; do
-        if [ -d "$i/lib/aspell" ]; then
-            export ASPELL_CONF="dict-dir $i/lib/aspell"
-        fi
-    done
-
     # Set $NIX_SSL_CERT_FILE so that Nixpkgs applications like curl work.
     if [ -e /etc/ssl/certs/ca-certificates.crt ]; then # NixOS, Ubuntu, Debian, Gentoo, Arch
         export NIX_SSL_CERT_FILE=/etc/ssl/certs/ca-certificates.crt
@@ -81,7 +75,7 @@ if [ -n "$HOME" ] && [ -n "$USER" ]; then
         export NIX_SSL_CERT_FILE="$NIX_LINK/etc/ca-bundle.crt"
     fi
 
-    if [ -n ${MANPATH} ]; then
+    if [ -n "${MANPATH}" ]; then
         export MANPATH="$NIX_LINK/share/man:$MANPATH"
     fi
 

shell.nix

@@ -22,6 +22,10 @@ with import ./release-common.nix { inherit pkgs; };
       # For nix-perl
       perl
       perlPackages.DBDSQLite
+
+      # Tests
+      git
+      mercurial
     ]
     ++ lib.optional stdenv.isLinux libseccomp;
 

src/build-remote/build-remote.cc

@@ -16,6 +16,7 @@
 #include "serialise.hh"
 #include "store-api.hh"
 #include "derivations.hh"
+#include "local-store.hh"
 
 using namespace nix;
 using std::cin;
@@ -41,24 +42,35 @@ int main (int argc, char * * argv)
     return handleExceptions(argv[0], [&]() {
         initNix();
 
+        logger = makeJSONLogger(*logger);
+
         /* Ensure we don't get any SSH passphrase or host key popups. */
         unsetenv("DISPLAY");
         unsetenv("SSH_ASKPASS");
 
-        if (argc != 6)
+        if (argc != 2)
             throw UsageError("called without required arguments");
 
-        auto store = openStore();
+        verbosity = (Verbosity) std::stoll(argv[1]);
 
-        auto localSystem = argv[1];
-        settings.maxSilentTime = std::stoll(argv[2]);
-        settings.buildTimeout = std::stoll(argv[3]);
-        verbosity = (Verbosity) std::stoll(argv[4]);
-        settings.builders = argv[5];
+        FdSource source(STDIN_FILENO);
+
+        /* Read the parent's settings. */
+        while (readInt(source)) {
+            auto name = readString(source);
+            auto value = readString(source);
+            settings.set(name, value);
+        }
+
+        settings.maxBuildJobs.set("1"); // hack to make tests with local?root= work
+
+        initPlugins();
+
+        auto store = openStore().cast<LocalStore>();
 
         /* It would be more appropriate to use $XDG_RUNTIME_DIR, since
-           that gets cleared on reboot, but it wouldn't work on OS X. */
-        currentLoad = settings.nixStateDir + "/current-load";
+           that gets cleared on reboot, but it wouldn't work on macOS. */
+        currentLoad = store->stateDir + "/current-load";
 
         std::shared_ptr<Store> sshStore;
         AutoCloseFD bestSlotLock;
@@ -73,18 +85,20 @@ int main (int argc, char * * argv)
 
         string drvPath;
         string storeUri;
-        for (string line; getline(cin, line);) {
-            auto tokens = tokenizeString<std::vector<string>>(line);
-            auto sz = tokens.size();
-            if (sz != 3 && sz != 4)
-                throw Error("invalid build hook line ‘%1%’", line);
-            auto amWilling = tokens[0] == "1";
-            auto neededSystem = tokens[1];
-            drvPath = tokens[2];
-            auto requiredFeatures = sz == 3 ?
-                std::set<string>{} :
-                tokenizeString<std::set<string>>(tokens[3], ",");
-            auto canBuildLocally = amWilling && (neededSystem == localSystem);
+
+        while (true) {
+
+            try {
+                auto s = readString(source);
+                if (s != "try") return;
+            } catch (EndOfFile &) { return; }
+
+            auto amWilling = readInt(source);
+            auto neededSystem = readString(source);
+            source >> drvPath;
+            auto requiredFeatures = readStrings<std::set<std::string>>(source);
+
+            auto canBuildLocally = amWilling && (neededSystem == settings.thisSystem);
 
             /* Error ignored here, will be caught later */
             mkdir(currentLoad.c_str(), 0777);
@@ -99,7 +113,7 @@ int main (int argc, char * * argv)
                 Machine * bestMachine = nullptr;
                 unsigned long long bestLoad = 0;
                 for (auto & m : machines) {
-                    debug("considering building on ‘%s’", m.storeUri);
+                    debug("considering building on remote machine '%s'", m.storeUri);
 
                     if (m.enabled && std::find(m.systemTypes.begin(),
                             m.systemTypes.end(),
@@ -162,16 +176,22 @@ int main (int argc, char * * argv)
 
                 try {
 
-                    Store::Params storeParams{{"max-connections", "1"}, {"log-fd", "4"}};
-                    if (bestMachine->sshKey != "")
-                        storeParams["ssh-key"] = bestMachine->sshKey;
+                    Activity act(*logger, lvlTalkative, actUnknown, fmt("connecting to '%s'", bestMachine->storeUri));
+
+                    Store::Params storeParams;
+                    if (hasPrefix(bestMachine->storeUri, "ssh://")) {
+                        storeParams["max-connections"] ="1";
+                        storeParams["log-fd"] = "4";
+                        if (bestMachine->sshKey != "")
+                            storeParams["ssh-key"] = bestMachine->sshKey;
+                    }
 
                     sshStore = openStore(bestMachine->storeUri, storeParams);
                     sshStore->connect();
                     storeUri = bestMachine->storeUri;
 
                 } catch (std::exception & e) {
-                    printError("unable to open SSH connection to ‘%s’: %s; trying other available machines...",
+                    printError("unable to open SSH connection to '%s': %s; trying other available machines...",
                         bestMachine->storeUri, e.what());
                     bestMachine->enabled = false;
                     continue;
@@ -182,44 +202,49 @@ int main (int argc, char * * argv)
         }
 
 connected:
-        std::cerr << "# accept\n";
-        string line;
-        if (!getline(cin, line))
-            throw Error("hook caller didn't send inputs");
+        std::cerr << "# accept\n" << storeUri << "\n";
 
-        auto inputs = tokenizeString<PathSet>(line);
-        if (!getline(cin, line))
-            throw Error("hook caller didn't send outputs");
-
-        auto outputs = tokenizeString<PathSet>(line);
+        auto inputs = readStrings<PathSet>(source);
+        auto outputs = readStrings<PathSet>(source);
 
         AutoCloseFD uploadLock = openLockFile(currentLoad + "/" + escapeUri(storeUri) + ".upload-lock", true);
 
-        auto old = signal(SIGALRM, handleAlarm);
-        alarm(15 * 60);
-        if (!lockFile(uploadLock.get(), ltWrite, true))
-            printError("somebody is hogging the upload lock for ‘%s’, continuing...");
-        alarm(0);
-        signal(SIGALRM, old);
-        copyPaths(store, ref<Store>(sshStore), inputs, false, true);
+        {
+            Activity act(*logger, lvlTalkative, actUnknown, fmt("waiting for the upload lock to '%s'", storeUri));
+
+            auto old = signal(SIGALRM, handleAlarm);
+            alarm(15 * 60);
+            if (!lockFile(uploadLock.get(), ltWrite, true))
+                printError("somebody is hogging the upload lock for '%s', continuing...");
+            alarm(0);
+            signal(SIGALRM, old);
+        }
+
+        auto substitute = settings.buildersUseSubstitutes ? Substitute : NoSubstitute;
+
+        {
+            Activity act(*logger, lvlTalkative, actUnknown, fmt("copying dependencies to '%s'", storeUri));
+            copyPaths(store, ref<Store>(sshStore), inputs, NoRepair, NoCheckSigs, substitute);
+        }
+
         uploadLock = -1;
 
-        BasicDerivation drv(readDerivation(drvPath));
+        BasicDerivation drv(readDerivation(store->realStoreDir + "/" + baseNameOf(drvPath)));
         drv.inputSrcs = inputs;
 
-        printError("building ‘%s’ on ‘%s’", drvPath, storeUri);
         auto result = sshStore->buildDerivation(drvPath, drv);
 
         if (!result.success())
-            throw Error("build of ‘%s’ on ‘%s’ failed: %s", drvPath, storeUri, result.errorMsg);
+            throw Error("build of '%s' on '%s' failed: %s", drvPath, storeUri, result.errorMsg);
 
         PathSet missing;
         for (auto & path : outputs)
             if (!store->isValidPath(path)) missing.insert(path);
 
         if (!missing.empty()) {
-            setenv("NIX_HELD_LOCKS", concatStringsSep(" ", missing).c_str(), 1); /* FIXME: ugly */
-            copyPaths(ref<Store>(sshStore), store, missing, false, true);
+            Activity act(*logger, lvlTalkative, actUnknown, fmt("copying outputs from '%s'", storeUri));
+            store->locksHeld.insert(missing.begin(), missing.end()); /* FIXME: ugly */
+            copyPaths(ref<Store>(sshStore), store, missing, NoRepair, NoCheckSigs, NoSubstitute);
         }
 
         return;

src/buildenv/buildenv.cc

@@ -12,7 +12,7 @@ static bool isDirectory (const Path & path)
 {
     struct stat st;
     if (stat(path.c_str(), &st) == -1)
-        throw SysError(format("getting status of ‘%1%’") % path);
+        throw SysError(format("getting status of '%1%'") % path);
     return S_ISDIR(st.st_mode);
 }
 
@@ -53,18 +53,18 @@ static void createLinks(const Path & srcDir, const Path & dstDir, int priority)
                 } else if (S_ISLNK(dstSt.st_mode)) {
                     auto target = readLink(dstFile);
                     if (!isDirectory(target))
-                        throw Error(format("collision between ‘%1%’ and non-directory ‘%2%’")
+                        throw Error(format("collision between '%1%' and non-directory '%2%'")
                             % srcFile % target);
                     if (unlink(dstFile.c_str()) == -1)
-                        throw SysError(format("unlinking ‘%1%’") % dstFile);
+                        throw SysError(format("unlinking '%1%'") % dstFile);
                     if (mkdir(dstFile.c_str(), 0755) == -1)
-                        throw SysError(format("creating directory ‘%1%’"));
+                        throw SysError(format("creating directory '%1%'"));
                     createLinks(target, dstFile, priorities[dstFile]);
                     createLinks(srcFile, dstFile, priority);
                     continue;
                 }
             } else if (errno != ENOENT)
-                throw SysError(format("getting status of ‘%1%’") % dstFile);
+                throw SysError(format("getting status of '%1%'") % dstFile);
         } else {
             struct stat dstSt;
             auto res = lstat(dstFile.c_str(), &dstSt);
@@ -74,17 +74,18 @@ static void createLinks(const Path & srcDir, const Path & dstDir, int priority)
                     auto prevPriority = priorities[dstFile];
                     if (prevPriority == priority)
                         throw Error(format(
-                                "collision between ‘%1%’ and ‘%2%’; "
-                                "use ‘nix-env --set-flag priority NUMBER PKGNAME’ "
+                                "packages '%1%' and '%2%' have the same priority %3%; "
+                                "use 'nix-env --set-flag priority NUMBER INSTALLED_PKGNAME' "
                                 "to change the priority of one of the conflicting packages"
-                                ) % srcFile % target);
+                                " (0 being the highest priority)"
+                                ) % srcFile % target % priority);
                     if (prevPriority < priority)
                         continue;
                     if (unlink(dstFile.c_str()) == -1)
-                        throw SysError(format("unlinking ‘%1%’") % dstFile);
+                        throw SysError(format("unlinking '%1%'") % dstFile);
                 }
             } else if (errno != ENOENT)
-                throw SysError(format("getting status of ‘%1%’") % dstFile);
+                throw SysError(format("getting status of '%1%'") % dstFile);
         }
         createSymlink(srcFile, dstFile);
         priorities[dstFile] = priority;
@@ -112,11 +113,11 @@ static void addPkg(const Path & pkgDir, int priority)
         if (!fd) {
             if (errno == ENOENT)
                 return;
-            throw SysError(format("opening ‘%1%’") % propagatedFN);
+            throw SysError(format("opening '%1%'") % propagatedFN);
         }
-        propagated = readLine(fd.get());
+        propagated = readFile(fd.get());
     }
-    for (const auto & p : tokenizeString<std::vector<string>>(propagated, " "))
+    for (const auto & p : tokenizeString<std::vector<string>>(propagated, " \n"))
         if (done.find(p) == done.end())
             postponed.insert(p);
 }

src/libexpr/attr-path.cc

@@ -19,7 +19,7 @@ static Strings parseAttrPath(const string & s)
             ++i;
             while (1) {
                 if (i == s.end())
-                    throw Error(format("missing closing quote in selection path ‘%1%’") % s);
+                    throw Error(format("missing closing quote in selection path '%1%'") % s);
                 if (*i == '"') break;
                 cur.push_back(*i++);
             }
@@ -38,7 +38,7 @@ Value * findAlongAttrPath(EvalState & state, const string & attrPath,
     Strings tokens = parseAttrPath(attrPath);
 
     Error attrError =
-        Error(format("attribute selection path ‘%1%’ does not match expression") % attrPath);
+        Error(format("attribute selection path '%1%' does not match expression") % attrPath);
 
     Value * v = &vIn;
 
@@ -62,15 +62,15 @@ Value * findAlongAttrPath(EvalState & state, const string & attrPath,
 
             if (v->type != tAttrs)
                 throw TypeError(
-                    format("the expression selected by the selection path ‘%1%’ should be a set but is %2%")
+                    format("the expression selected by the selection path '%1%' should be a set but is %2%")
                     % attrPath % showType(*v));
 
             if (attr.empty())
-                throw Error(format("empty attribute name in selection path ‘%1%’") % attrPath);
+                throw Error(format("empty attribute name in selection path '%1%'") % attrPath);
 
             Bindings::iterator a = v->attrs->find(state.symbols.create(attr));
             if (a == v->attrs->end())
-                throw Error(format("attribute ‘%1%’ in selection path ‘%2%’ not found") % attr % attrPath);
+                throw Error(format("attribute '%1%' in selection path '%2%' not found") % attr % attrPath);
             v = &*a->value;
         }
 
@@ -78,11 +78,11 @@ Value * findAlongAttrPath(EvalState & state, const string & attrPath,
 
             if (!v->isList())
                 throw TypeError(
-                    format("the expression selected by the selection path ‘%1%’ should be a list but is %2%")
+                    format("the expression selected by the selection path '%1%' should be a list but is %2%")
                     % attrPath % showType(*v));
 
             if (attrIndex >= v->listSize())
-                throw Error(format("list index %1% in selection path ‘%2%’ is out of range") % attrIndex % attrPath);
+                throw Error(format("list index %1% in selection path '%2%' is out of range") % attrIndex % attrPath);
 
             v = v->listElems()[attrIndex];
         }

src/libexpr/attr-set.cc

@@ -7,13 +7,14 @@
 namespace nix {
 
 
+/* Note: Various places expect the allocated memory to be zeroed. */
 static void * allocBytes(size_t n)
 {
     void * p;
 #if HAVE_BOEHMGC
     p = GC_malloc(n);
 #else
-    p = malloc(n);
+    p = calloc(n, 1);
 #endif
     if (!p) throw std::bad_alloc();
     return p;

src/libexpr/attr-set.hh

@@ -83,7 +83,7 @@ public:
         for (size_t n = 0; n < size_; n++)
             res.emplace_back(&attrs[n]);
         std::sort(res.begin(), res.end(), [](const Attr * a, const Attr * b) {
-            return (string) a->name < (string) b->name;
+            return (const string &) a->name < (const string &) b->name;
         });
         return res;
     }

src/libexpr/common-eval-args.cc

@@ -0,0 +1,57 @@
+#include "common-eval-args.hh"
+#include "shared.hh"
+#include "download.hh"
+#include "util.hh"
+#include "eval.hh"
+
+namespace nix {
+
+MixEvalArgs::MixEvalArgs()
+{
+    mkFlag()
+        .longName("arg")
+        .description("argument to be passed to Nix functions")
+        .labels({"name", "expr"})
+        .handler([&](std::vector<std::string> ss) { autoArgs[ss[0]] = 'E' + ss[1]; });
+
+    mkFlag()
+        .longName("argstr")
+        .description("string-valued argument to be passed to Nix functions")
+        .labels({"name", "string"})
+        .handler([&](std::vector<std::string> ss) { autoArgs[ss[0]] = 'S' + ss[1]; });
+
+    mkFlag()
+        .shortName('I')
+        .longName("include")
+        .description("add a path to the list of locations used to look up <...> file names")
+        .label("path")
+        .handler([&](std::string s) { searchPath.push_back(s); });
+}
+
+Bindings * MixEvalArgs::getAutoArgs(EvalState & state)
+{
+    Bindings * res = state.allocBindings(autoArgs.size());
+    for (auto & i : autoArgs) {
+        Value * v = state.allocValue();
+        if (i.second[0] == 'E')
+            state.mkThunk_(*v, state.parseExprFromString(string(i.second, 1), absPath(".")));
+        else
+            mkString(*v, string(i.second, 1));
+        res->push_back(Attr(state.symbols.create(i.first), v));
+    }
+    res->sort();
+    return res;
+}
+
+Path lookupFileArg(EvalState & state, string s)
+{
+    if (isUri(s))
+        return getDownloader()->downloadCached(state.store, s, true);
+    else if (s.size() > 2 && s.at(0) == '<' && s.at(s.size() - 1) == '>') {
+        Path p = s.substr(1, s.size() - 2);
+        return state.findFile(p);
+    } else
+        return absPath(s);
+}
+
+}

src/libexpr/common-eval-args.hh

@@ -0,0 +1,26 @@
+#pragma once
+
+#include "args.hh"
+
+namespace nix {
+
+class Store;
+class EvalState;
+class Bindings;
+
+struct MixEvalArgs : virtual Args
+{
+    MixEvalArgs();
+
+    Bindings * getAutoArgs(EvalState & state);
+
+    Strings searchPath;
+
+private:
+
+    std::map<std::string, std::string> autoArgs;
+};
+
+Path lookupFileArg(EvalState & state, string s);
+
+}

src/libexpr/common-opts.cc

@@ -1,67 +0,0 @@
-#include "common-opts.hh"
-#include "shared.hh"
-#include "download.hh"
-#include "util.hh"
-
-
-namespace nix {
-
-
-bool parseAutoArgs(Strings::iterator & i,
-    const Strings::iterator & argsEnd, std::map<string, string> & res)
-{
-    string arg = *i;
-    if (arg != "--arg" && arg != "--argstr") return false;
-
-    UsageError error(format("‘%1%’ requires two arguments") % arg);
-
-    if (++i == argsEnd) throw error;
-    string name = *i;
-    if (++i == argsEnd) throw error;
-    string value = *i;
-
-    res[name] = (arg == "--arg" ? 'E' : 'S') + value;
-
-    return true;
-}
-
-
-Bindings * evalAutoArgs(EvalState & state, std::map<string, string> & in)
-{
-    Bindings * res = state.allocBindings(in.size());
-    for (auto & i : in) {
-        Value * v = state.allocValue();
-        if (i.second[0] == 'E')
-            state.mkThunk_(*v, state.parseExprFromString(string(i.second, 1), absPath(".")));
-        else
-            mkString(*v, string(i.second, 1));
-        res->push_back(Attr(state.symbols.create(i.first), v));
-    }
-    res->sort();
-    return res;
-}
-
-
-bool parseSearchPathArg(Strings::iterator & i,
-    const Strings::iterator & argsEnd, Strings & searchPath)
-{
-    if (*i != "-I") return false;
-    if (++i == argsEnd) throw UsageError("‘-I’ requires an argument");
-    searchPath.push_back(*i);
-    return true;
-}
-
-
-Path lookupFileArg(EvalState & state, string s)
-{
-    if (isUri(s))
-        return getDownloader()->downloadCached(state.store, s, true);
-    else if (s.size() > 2 && s.at(0) == '<' && s.at(s.size() - 1) == '>') {
-        Path p = s.substr(1, s.size() - 2);
-        return state.findFile(p);
-    } else
-        return absPath(s);
-}
-
-
-}

src/libexpr/common-opts.hh

@@ -1,20 +0,0 @@
-#pragma once
-
-#include "eval.hh"
-
-namespace nix {
-
-class Store;
-
-/* Some common option parsing between nix-env and nix-instantiate. */
-bool parseAutoArgs(Strings::iterator & i,
-    const Strings::iterator & argsEnd, std::map<string, string> & res);
-
-Bindings * evalAutoArgs(EvalState & state, std::map<string, string> & in);
-
-bool parseSearchPathArg(Strings::iterator & i,
-    const Strings::iterator & argsEnd, Strings & searchPath);
-
-Path lookupFileArg(EvalState & state, string s);
-
-}

src/libexpr/eval-inline.hh

@@ -33,7 +33,7 @@ void EvalState::forceValue(Value & v, const Pos & pos)
             v.type = tBlackhole;
             //checkInterrupt();
             expr->eval(*this, *env, v);
-        } catch (Error & e) {
+        } catch (...) {
             v.type = tThunk;
             v.thunk.env = env;
             v.thunk.expr = expr;

src/libexpr/eval.cc

@@ -43,13 +43,14 @@ static char * dupString(const char * s)
 }
 
 
+/* Note: Various places expect the allocated memory to be zeroed. */
 static void * allocBytes(size_t n)
 {
     void * p;
 #if HAVE_BOEHMGC
     p = GC_malloc(n);
 #else
-    p = malloc(n);
+    p = calloc(n, 1);
 #endif
     if (!p) throw std::bad_alloc();
     return p;
@@ -149,7 +150,7 @@ string showType(const Value & v)
     switch (v.type) {
         case tInt: return "an integer";
         case tBool: return "a boolean";
-        case tString: return "a string";
+        case tString: return v.string.context ? "a string with context" : "a string";
         case tPath: return "a path";
         case tNull: return "null";
         case tAttrs: return "a set";
@@ -293,21 +294,35 @@ EvalState::EvalState(const Strings & _searchPath, ref<Store> store)
     , sWrong(symbols.create("wrong"))
     , sStructuredAttrs(symbols.create("__structuredAttrs"))
     , sBuilder(symbols.create("builder"))
+    , sArgs(symbols.create("args"))
+    , sOutputHash(symbols.create("outputHash"))
+    , sOutputHashAlgo(symbols.create("outputHashAlgo"))
+    , sOutputHashMode(symbols.create("outputHashMode"))
+    , repair(NoRepair)
     , store(store)
     , baseEnv(allocEnv(128))
     , staticBaseEnv(false, 0)
 {
     countCalls = getEnv("NIX_COUNT_CALLS", "0") != "0";
 
-    restricted = settings.restrictEval;
-
     assert(gcInitialised);
 
     /* Initialise the Nix expression search path. */
-    Strings paths = parseNixPath(getEnv("NIX_PATH", ""));
-    for (auto & i : _searchPath) addToSearchPath(i);
-    for (auto & i : paths) addToSearchPath(i);
-    addToSearchPath("nix=" + settings.nixDataDir + "/nix/corepkgs");
+    if (!settings.pureEval) {
+        Strings paths = parseNixPath(getEnv("NIX_PATH", ""));
+        for (auto & i : _searchPath) addToSearchPath(i);
+        for (auto & i : paths) addToSearchPath(i);
+    }
+    addToSearchPath("nix=" + canonPath(settings.nixDataDir + "/nix/corepkgs", true));
+
+    if (settings.restrictEval || settings.pureEval) {
+        allowedPaths = PathSet();
+        for (auto & i : searchPath) {
+            auto r = resolveSearchPathElem(i);
+            if (!r.first) continue;
+            allowedPaths->insert(r.second);
+        }
+    }
 
     clearValue(vEmptySet);
     vEmptySet.type = tAttrs;
@@ -325,36 +340,76 @@ EvalState::~EvalState()
 
 Path EvalState::checkSourcePath(const Path & path_)
 {
-    if (!restricted) return path_;
+    if (!allowedPaths) return path_;
+
+    bool found = false;
+
+    for (auto & i : *allowedPaths) {
+        if (isDirOrInDir(path_, i)) {
+            found = true;
+            break;
+        }
+    }
+
+    if (!found)
+        throw RestrictedPathError("access to path '%1%' is forbidden in restricted mode", path_);
 
     /* Resolve symlinks. */
-    debug(format("checking access to ‘%s’") % path_);
+    debug(format("checking access to '%s'") % path_);
     Path path = canonPath(path_, true);
 
-    for (auto & i : searchPath) {
-        auto r = resolveSearchPathElem(i);
-        if (!r.first) continue;
-        if (path == r.second || isInDir(path, r.second))
+    for (auto & i : *allowedPaths) {
+        if (isDirOrInDir(path, i))
             return path;
     }
 
-    /* To support import-from-derivation, allow access to anything in
-       the store. FIXME: only allow access to paths that have been
-       constructed by this evaluation. */
-    if (store->isInStore(path)) return path;
-
-#if 0
-    /* Hack to support the chroot dependencies of corepkgs (see
-       corepkgs/config.nix.in). */
-    if (path == settings.nixPrefix && isStorePath(settings.nixPrefix))
-        return path;
-#endif
-
-    throw RestrictedPathError(format("access to path ‘%1%’ is forbidden in restricted mode") % path_);
+    throw RestrictedPathError("access to path '%1%' is forbidden in restricted mode", path);
 }
 
 
-void EvalState::addConstant(const string & name, Value & v)
+void EvalState::checkURI(const std::string & uri)
+{
+    if (!settings.restrictEval) return;
+
+    /* 'uri' should be equal to a prefix, or in a subdirectory of a
+       prefix. Thus, the prefix https://github.co does not permit
+       access to https://github.com. Note: this allows 'http://' and
+       'https://' as prefixes for any http/https URI. */
+    for (auto & prefix : settings.allowedUris.get())
+        if (uri == prefix ||
+            (uri.size() > prefix.size()
+            && prefix.size() > 0
+            && hasPrefix(uri, prefix)
+            && (prefix[prefix.size() - 1] == '/' || uri[prefix.size()] == '/')))
+            return;
+
+    /* If the URI is a path, then check it against allowedPaths as
+       well. */
+    if (hasPrefix(uri, "/")) {
+        checkSourcePath(uri);
+        return;
+    }
+
+    if (hasPrefix(uri, "file://")) {
+        checkSourcePath(std::string(uri, 7));
+        return;
+    }
+
+    throw RestrictedPathError("access to URI '%s' is forbidden in restricted mode", uri);
+}
+
+
+Path EvalState::toRealPath(const Path & path, const PathSet & context)
+{
+    // FIXME: check whether 'path' is in 'context'.
+    return
+        !context.empty() && store->isInStore(path)
+        ? store->toRealPath(path)
+        : path;
+};
+
+
+Value * EvalState::addConstant(const string & name, Value & v)
 {
     Value * v2 = allocValue();
     *v2 = v;
@@ -362,12 +417,18 @@ void EvalState::addConstant(const string & name, Value & v)
     baseEnv.values[baseEnvDispl++] = v2;
     string name2 = string(name, 0, 2) == "__" ? string(name, 2) : name;
     baseEnv.values[0]->attrs->push_back(Attr(symbols.create(name2), v2));
+    return v2;
 }
 
 
-void EvalState::addPrimOp(const string & name,
+Value * EvalState::addPrimOp(const string & name,
     unsigned int arity, PrimOpFun primOp)
 {
+    if (arity == 0) {
+        Value v;
+        primOp(*this, noPos, nullptr, v);
+        return addConstant(name, v);
+    }
     Value * v = allocValue();
     string name2 = string(name, 0, 2) == "__" ? string(name, 2) : name;
     Symbol sym = symbols.create(name2);
@@ -376,6 +437,7 @@ void EvalState::addPrimOp(const string & name,
     staticBaseEnv.vars[symbols.create(name)] = baseEnvDispl;
     baseEnv.values[baseEnvDispl++] = v;
     baseEnv.values[0]->attrs->push_back(Attr(sym, v));
+    return v;
 }
 
 
@@ -503,7 +565,7 @@ inline Value * EvalState::lookupVar(Env * env, const ExprVar & var, bool noEval)
             return j->value;
         }
         if (!env->prevWith)
-            throwUndefinedVarError("undefined variable ‘%1%’ at %2%", var.name, var.pos);
+            throwUndefinedVarError("undefined variable '%1%' at %2%", var.name, var.pos);
         for (unsigned int l = env->prevWith; l; --l, env = env->up) ;
     }
 }
@@ -525,9 +587,7 @@ Env & EvalState::allocEnv(unsigned int size)
     Env * env = (Env *) allocBytes(sizeof(Env) + size * sizeof(Value *));
     env->size = size;
 
-    /* Clear the values because maybeThunk() and lookupVar fromWith expect this. */
-    for (unsigned i = 0; i < size; ++i)
-        env->values[i] = 0;
+    /* We assume that env->values has been cleared by the allocator; maybeThunk() and lookupVar fromWith expect this. */
 
     return *env;
 }
@@ -628,8 +688,10 @@ Value * ExprPath::maybeThunk(EvalState & state, Env & env)
 }
 
 
-void EvalState::evalFile(const Path & path, Value & v)
+void EvalState::evalFile(const Path & path_, Value & v)
 {
+    auto path = checkSourcePath(path_);
+
     FileEvalCache::iterator i;
     if ((i = fileEvalCache.find(path)) != fileEvalCache.end()) {
         v = i->second;
@@ -642,12 +704,12 @@ void EvalState::evalFile(const Path & path, Value & v)
         return;
     }
 
-    printTalkative("evaluating file ‘%1%’", path2);
+    printTalkative("evaluating file '%1%'", path2);
     Expr * e = parseExprFromFile(checkSourcePath(path2));
     try {
         eval(e, v);
     } catch (Error & e) {
-        addErrorPrefix(e, "while evaluating the file ‘%1%’:\n", path2);
+        addErrorPrefix(e, "while evaluating the file '%1%':\n", path2);
         throw;
     }
 
@@ -797,7 +859,7 @@ void ExprAttrs::eval(EvalState & state, Env & env, Value & v)
         Symbol nameSym = state.symbols.create(nameVal.string.s);
         Bindings::iterator j = v.attrs->find(nameSym);
         if (j != v.attrs->end())
-            throwEvalError("dynamic attribute ‘%1%’ at %2% already defined at %3%", nameSym, i.pos, *j->pos);
+            throwEvalError("dynamic attribute '%1%' at %2% already defined at %3%", nameSym, i.pos, *j->pos);
 
         i.valueExpr->setName(nameSym);
         /* Keep sorted order so find can catch duplicates */
@@ -885,7 +947,7 @@ void ExprSelect::eval(EvalState & state, Env & env, Value & v)
             } else {
                 state.forceAttrs(*vAttrs, pos);
                 if ((j = vAttrs->attrs->find(name)) == vAttrs->attrs->end())
-                    throwEvalError("attribute ‘%1%’ missing, at %2%", name, pos);
+                    throwEvalError("attribute '%1%' missing, at %2%", name, pos);
             }
             vAttrs = j->value;
             pos2 = j->pos;
@@ -896,7 +958,7 @@ void ExprSelect::eval(EvalState & state, Env & env, Value & v)
 
     } catch (Error & e) {
         if (pos2 && pos2->file != state.sDerivationNix)
-            addErrorPrefix(e, "while evaluating the attribute ‘%1%’ at %2%:\n",
+            addErrorPrefix(e, "while evaluating the attribute '%1%' at %2%:\n",
                 showAttrPath(state, env, attrPath), *pos2);
         throw;
     }
@@ -1038,7 +1100,7 @@ void EvalState::callFunction(Value & fun, Value & arg, Value & v, const Pos & po
         for (auto & i : lambda.formals->formals) {
             Bindings::iterator j = arg.attrs->find(i.name);
             if (j == arg.attrs->end()) {
-                if (!i.def) throwTypeError("%1% called without required argument ‘%2%’, at %3%",
+                if (!i.def) throwTypeError("%1% called without required argument '%2%', at %3%",
                     lambda, i.name, pos);
                 env2.values[displ++] = i.def->maybeThunk(*this, env2);
             } else {
@@ -1054,7 +1116,7 @@ void EvalState::callFunction(Value & fun, Value & arg, Value & v, const Pos & po
                user. */
             for (auto & i : *arg.attrs)
                 if (lambda.formals->argNames.find(i.name) == lambda.formals->argNames.end())
-                    throwTypeError("%1% called with unexpected argument ‘%2%’, at %3%", lambda, i.name, pos);
+                    throwTypeError("%1% called with unexpected argument '%2%', at %3%", lambda, i.name, pos);
             abort(); // can't happen
         }
     }
@@ -1112,7 +1174,7 @@ void EvalState::autoCallFunction(Bindings & args, Value & fun, Value & res)
         if (j != args.end())
             actualArgs->attrs->push_back(*j);
         else if (!i.def)
-            throwTypeError("cannot auto-call a function that has an argument without a default value (‘%1%’)", i.name);
+            throwTypeError("cannot auto-call a function that has an argument without a default value ('%1%')", i.name);
     }
 
     actualArgs->attrs->sort();
@@ -1341,7 +1403,7 @@ void EvalState::forceValueDeep(Value & v)
                 try {
                     recurse(*i.value);
                 } catch (Error & e) {
-                    addErrorPrefix(e, "while evaluating the attribute ‘%1%’ at %2%:\n", i.name, *i.pos);
+                    addErrorPrefix(e, "while evaluating the attribute '%1%' at %2%:\n", i.name, *i.pos);
                     throw;
                 }
         }
@@ -1433,10 +1495,10 @@ string EvalState::forceStringNoCtx(Value & v, const Pos & pos)
     string s = forceString(v, pos);
     if (v.string.context) {
         if (pos)
-            throwEvalError("the string ‘%1%’ is not allowed to refer to a store path (such as ‘%2%’), at %3%",
+            throwEvalError("the string '%1%' is not allowed to refer to a store path (such as '%2%'), at %3%",
                 v.string.s, v.string.context[0], pos);
         else
-            throwEvalError("the string ‘%1%’ is not allowed to refer to a store path (such as ‘%2%’)",
+            throwEvalError("the string '%1%' is not allowed to refer to a store path (such as '%2%')",
                 v.string.s, v.string.context[0]);
     }
     return s;
@@ -1518,17 +1580,17 @@ string EvalState::coerceToString(const Pos & pos, Value & v, PathSet & context,
 string EvalState::copyPathToStore(PathSet & context, const Path & path)
 {
     if (nix::isDerivation(path))
-        throwEvalError("file names are not allowed to end in ‘%1%’", drvExtension);
+        throwEvalError("file names are not allowed to end in '%1%'", drvExtension);
 
     Path dstPath;
     if (srcToStore[path] != "")
         dstPath = srcToStore[path];
     else {
         dstPath = settings.readOnlyMode
-            ? store->computeStorePathForPath(checkSourcePath(path)).first
+            ? store->computeStorePathForPath(baseNameOf(path), checkSourcePath(path)).first
             : store->addToStore(baseNameOf(path), checkSourcePath(path), true, htSHA256, defaultPathFilter, repair);
         srcToStore[path] = dstPath;
-        printMsg(lvlChatty, format("copied source ‘%1%’ -> ‘%2%’")
+        printMsg(lvlChatty, format("copied source '%1%' -> '%2%'")
             % path % dstPath);
     }
 
@@ -1541,7 +1603,7 @@ Path EvalState::coerceToPath(const Pos & pos, Value & v, PathSet & context)
 {
     string path = coerceToString(pos, v, context, false, false);
     if (path == "" || path[0] != '/')
-        throwEvalError("string ‘%1%’ doesn't represent an absolute path, at %2%", path, pos);
+        throwEvalError("string '%1%' doesn't represent an absolute path, at %2%", path, pos);
     return path;
 }
 
@@ -1647,10 +1709,13 @@ void EvalState::printStats()
     printMsg(v, format("  time elapsed: %1%") % cpuTime);
     printMsg(v, format("  size of a value: %1%") % sizeof(Value));
     printMsg(v, format("  size of an attr: %1%") % sizeof(Attr));
-    printMsg(v, format("  environments allocated: %1% (%2% bytes)") % nrEnvs % bEnvs);
-    printMsg(v, format("  list elements: %1% (%2% bytes)") % nrListElems % bLists);
+    printMsg(v, format("  environments allocated count: %1%") % nrEnvs);
+    printMsg(v, format("  environments allocated bytes: %1%") % bEnvs);
+    printMsg(v, format("  list elements count: %1%") % nrListElems);
+    printMsg(v, format("  list elements bytes: %1%") % bLists);
     printMsg(v, format("  list concatenations: %1%") % nrListConcats);
-    printMsg(v, format("  values allocated: %1% (%2% bytes)") % nrValues % bValues);
+    printMsg(v, format("  values allocated count: %1%") % nrValues);
+    printMsg(v, format("  values allocated bytes: %1%") % bValues);
     printMsg(v, format("  sets allocated: %1% (%2% bytes)") % nrAttrsets % bAttrsets);
     printMsg(v, format("  right-biased unions: %1%") % nrOpUpdates);
     printMsg(v, format("  values copied in right-biased unions: %1%") % nrOpUpdateValuesCopied);

src/libexpr/eval.hh

@@ -14,6 +14,7 @@ namespace nix {
 
 class Store;
 class EvalState;
+enum RepairFlag : bool;
 
 
 typedef void (* PrimOpFun) (EvalState & state, const Pos & pos, Value * * args, Value & v);
@@ -68,16 +69,17 @@ public:
     const Symbol sWith, sOutPath, sDrvPath, sType, sMeta, sName, sValue,
         sSystem, sOverrides, sOutputs, sOutputName, sIgnoreNulls,
         sFile, sLine, sColumn, sFunctor, sToString,
-        sRight, sWrong, sStructuredAttrs, sBuilder;
+        sRight, sWrong, sStructuredAttrs, sBuilder, sArgs,
+        sOutputHash, sOutputHashAlgo, sOutputHashMode;
     Symbol sDerivationNix;
 
     /* If set, force copying files to the Nix store even if they
        already exist there. */
-    bool repair = false;
+    RepairFlag repair;
 
-    /* If set, don't allow access to files outside of the Nix search
-       path or to environment variables. */
-    bool restricted;
+    /* The allowed filesystem paths in restricted or pure evaluation
+       mode. */
+    std::experimental::optional<PathSet> allowedPaths;
 
     Value vEmptySet;
 
@@ -109,6 +111,17 @@ public:
 
     Path checkSourcePath(const Path & path);
 
+    void checkURI(const std::string & uri);
+
+    /* When using a diverted store and 'path' is in the Nix store, map
+       'path' to the diverted location (e.g. /nix/store/foo is mapped
+       to /home/alice/my-nix/nix/store/foo). However, this is only
+       done if the context is not empty, since otherwise we're
+       probably trying to read from the actual /nix/store. This is
+       intended to distinguish between import-from-derivation and
+       sources stored in the actual /nix/store. */
+    Path toRealPath(const Path & path, const PathSet & context);
+
     /* Parse a Nix expression from the specified file. */
     Expr * parseExprFromFile(const Path & path);
     Expr * parseExprFromFile(const Path & path, StaticEnv & staticEnv);
@@ -117,6 +130,8 @@ public:
     Expr * parseExprFromString(const string & s, const Path & basePath, StaticEnv & staticEnv);
     Expr * parseExprFromString(const string & s, const Path & basePath);
 
+    Expr * parseStdin();
+
     /* Evaluate an expression read from the given file to normal
        form. */
     void evalFile(const Path & path, Value & v);
@@ -196,9 +211,9 @@ private:
 
     void createBaseEnv();
 
-    void addConstant(const string & name, Value & v);
+    Value * addConstant(const string & name, Value & v);
 
-    void addPrimOp(const string & name,
+    Value * addPrimOp(const string & name,
         unsigned int arity, PrimOpFun primOp);
 
 public:

src/libexpr/get-drvs.cc

@@ -1,6 +1,7 @@
 #include "get-drvs.hh"
 #include "util.hh"
 #include "eval-inline.hh"
+#include "derivations.hh"
 
 #include <cstring>
 #include <regex>
@@ -9,7 +10,61 @@
 namespace nix {
 
 
-string DrvInfo::queryDrvPath()
+DrvInfo::DrvInfo(EvalState & state, const string & attrPath, Bindings * attrs)
+    : state(&state), attrs(attrs), attrPath(attrPath)
+{
+}
+
+
+DrvInfo::DrvInfo(EvalState & state, ref<Store> store, const std::string & drvPathWithOutputs)
+    : state(&state), attrs(nullptr), attrPath("")
+{
+    auto spec = parseDrvPathWithOutputs(drvPathWithOutputs);
+
+    drvPath = spec.first;
+
+    auto drv = store->derivationFromPath(drvPath);
+
+    name = storePathToName(drvPath);
+
+    if (spec.second.size() > 1)
+        throw Error("building more than one derivation output is not supported, in '%s'", drvPathWithOutputs);
+
+    outputName =
+        spec.second.empty()
+        ? get(drv.env, "outputName", "out")
+        : *spec.second.begin();
+
+    auto i = drv.outputs.find(outputName);
+    if (i == drv.outputs.end())
+        throw Error("derivation '%s' does not have output '%s'", drvPath, outputName);
+
+    outPath = i->second.path;
+}
+
+
+string DrvInfo::queryName() const
+{
+    if (name == "" && attrs) {
+        auto i = attrs->find(state->sName);
+        if (i == attrs->end()) throw TypeError("derivation name missing");
+        name = state->forceStringNoCtx(*i->value);
+    }
+    return name;
+}
+
+
+string DrvInfo::querySystem() const
+{
+    if (system == "" && attrs) {
+        auto i = attrs->find(state->sSystem);
+        system = i == attrs->end() ? "unknown" : state->forceStringNoCtx(*i->value, *i->pos);
+    }
+    return system;
+}
+
+
+string DrvInfo::queryDrvPath() const
 {
     if (drvPath == "" && attrs) {
         Bindings::iterator i = attrs->find(state->sDrvPath);
@@ -20,7 +75,7 @@ string DrvInfo::queryDrvPath()
 }
 
 
-string DrvInfo::queryOutPath()
+string DrvInfo::queryOutPath() const
 {
     if (outPath == "" && attrs) {
         Bindings::iterator i = attrs->find(state->sOutPath);
@@ -62,7 +117,7 @@ DrvInfo::Outputs DrvInfo::queryOutputs(bool onlyOutputsToInstall)
     /* Check for `meta.outputsToInstall` and return `outputs` reduced to that. */
     const Value * outTI = queryMeta("outputsToInstall");
     if (!outTI) return outputs;
-    const auto errMsg = Error("this derivation has bad ‘meta.outputsToInstall’");
+    const auto errMsg = Error("this derivation has bad 'meta.outputsToInstall'");
         /* ^ this shows during `nix-env -i` right under the bad derivation */
     if (!outTI->isList()) throw errMsg;
     Outputs result;
@@ -76,7 +131,7 @@ DrvInfo::Outputs DrvInfo::queryOutputs(bool onlyOutputsToInstall)
 }
 
 
-string DrvInfo::queryOutputName()
+string DrvInfo::queryOutputName() const
 {
     if (outputName == "" && attrs) {
         Bindings::iterator i = attrs->find(state->sOutputName);
@@ -225,17 +280,12 @@ static bool getDerivation(EvalState & state, Value & v,
         if (done.find(v.attrs) != done.end()) return false;
         done.insert(v.attrs);
 
-        Bindings::iterator i = v.attrs->find(state.sName);
-        /* !!! We really would like to have a decent back trace here. */
-        if (i == v.attrs->end()) throw TypeError("derivation name missing");
+        DrvInfo drv(state, attrPath, v.attrs);
 
-        Bindings::iterator i2 = v.attrs->find(state.sSystem);
-
-        DrvInfo drv(state, state.forceStringNoCtx(*i->value), attrPath,
-            i2 == v.attrs->end() ? "unknown" : state.forceStringNoCtx(*i2->value, *i2->pos),
-            v.attrs);
+        drv.queryName();
 
         drvs.push_back(drv);
+
         return false;
 
     } catch (AssertionError & e) {
@@ -245,15 +295,14 @@ static bool getDerivation(EvalState & state, Value & v,
 }
 
 
-bool getDerivation(EvalState & state, Value & v, DrvInfo & drv,
+std::experimental::optional<DrvInfo> getDerivation(EvalState & state, Value & v,
     bool ignoreAssertionFailures)
 {
     Done done;
     DrvInfos drvs;
     getDerivation(state, v, "", drvs, done, ignoreAssertionFailures);
-    if (drvs.size() != 1) return false;
-    drv = drvs.front();
-    return true;
+    if (drvs.size() != 1) return {};
+    return std::move(drvs.front());
 }
 
 
@@ -289,7 +338,7 @@ static void getDerivations(EvalState & state, Value & vIn,
            bound to the attribute with the "lower" name should take
            precedence). */
         for (auto & i : v.attrs->lexicographicOrder()) {
-            debug("evaluating attribute ‘%1%’", i->name);
+            debug("evaluating attribute '%1%'", i->name);
             if (!std::regex_match(std::string(i->name), attrRegex))
                 continue;
             string pathPrefix2 = addToPath(pathPrefix, i->name);

src/libexpr/get-drvs.hh

@@ -17,31 +17,33 @@ public:
 private:
     EvalState * state;
 
-    string drvPath;
-    string outPath;
-    string outputName;
+    mutable string name;
+    mutable string system;
+    mutable string drvPath;
+    mutable string outPath;
+    mutable string outputName;
     Outputs outputs;
 
-    bool failed; // set if we get an AssertionError
+    bool failed = false; // set if we get an AssertionError
 
-    Bindings * attrs, * meta;
+    Bindings * attrs = nullptr, * meta = nullptr;
 
     Bindings * getMeta();
 
     bool checkMeta(Value & v);
 
 public:
-    string name;
     string attrPath; /* path towards the derivation */
-    string system;
 
-    DrvInfo(EvalState & state) : state(&state), failed(false), attrs(0), meta(0) { };
-    DrvInfo(EvalState & state, const string & name, const string & attrPath, const string & system, Bindings * attrs)
-        : state(&state), failed(false), attrs(attrs), meta(0), name(name), attrPath(attrPath), system(system) { };
+    DrvInfo(EvalState & state) : state(&state) { };
+    DrvInfo(EvalState & state, const string & attrPath, Bindings * attrs);
+    DrvInfo(EvalState & state, ref<Store> store, const std::string & drvPathWithOutputs);
 
-    string queryDrvPath();
-    string queryOutPath();
-    string queryOutputName();
+    string queryName() const;
+    string querySystem() const;
+    string queryDrvPath() const;
+    string queryOutPath() const;
+    string queryOutputName() const;
     /** Return the list of outputs. The "outputs to install" are determined by `mesa.outputsToInstall`. */
     Outputs queryOutputs(bool onlyOutputsToInstall = false);
 
@@ -58,15 +60,9 @@ public:
     MetaValue queryMetaInfo(EvalState & state, const string & name) const;
     */
 
-    void setDrvPath(const string & s)
-    {
-        drvPath = s;
-    }
-
-    void setOutPath(const string & s)
-    {
-        outPath = s;
-    }
+    void setName(const string & s) { name = s; }
+    void setDrvPath(const string & s) { drvPath = s; }
+    void setOutPath(const string & s) { outPath = s; }
 
     void setFailed() { failed = true; };
     bool hasFailed() { return failed; };
@@ -80,10 +76,10 @@ typedef list<DrvInfo> DrvInfos;
 #endif
 
 
-/* If value `v' denotes a derivation, store information about the
-   derivation in `drv' and return true.  Otherwise, return false. */
-bool getDerivation(EvalState & state, Value & v, DrvInfo & drv,
-    bool ignoreAssertionFailures);
+/* If value `v' denotes a derivation, return a DrvInfo object
+   describing it. Otherwise return nothing. */
+std::experimental::optional<DrvInfo> getDerivation(EvalState & state,
+    Value & v, bool ignoreAssertionFailures);
 
 void getDerivations(EvalState & state, Value & v, const string & pathPrefix,
     Bindings & autoArgs, DrvInfos & drvs,

src/libexpr/json-to-value.cc

@@ -57,7 +57,7 @@ static void parseJSON(EvalState & state, const char * & s, Value & v)
             values.push_back(v2);
             skipWhitespace(s);
             if (*s == ']') break;
-            if (*s != ',') throw JSONParseError("expected ‘,’ or ‘]’ after JSON array element");
+            if (*s != ',') throw JSONParseError("expected ',' or ']' after JSON array element");
             s++;
         }
         s++;
@@ -74,14 +74,14 @@ static void parseJSON(EvalState & state, const char * & s, Value & v)
             if (attrs.empty() && *s == '}') break;
             string name = parseJSONString(s);
             skipWhitespace(s);
-            if (*s != ':') throw JSONParseError("expected ‘:’ in JSON object");
+            if (*s != ':') throw JSONParseError("expected ':' in JSON object");
             s++;
             Value * v2 = state.allocValue();
             parseJSON(state, s, *v2);
             attrs[state.symbols.create(name)] = v2;
             skipWhitespace(s);
             if (*s == '}') break;
-            if (*s != ',') throw JSONParseError("expected ‘,’ or ‘}’ after JSON member");
+            if (*s != ',') throw JSONParseError("expected ',' or '}' after JSON member");
             s++;
         }
         state.mkAttrs(v, attrs.size());
@@ -106,10 +106,16 @@ static void parseJSON(EvalState & state, const char * & s, Value & v)
             tmp_number += *s++;
         }
 
-        if (number_type == tFloat)
-            mkFloat(v, stod(tmp_number));
-        else
-            mkInt(v, stoi(tmp_number));
+        try {
+            if (number_type == tFloat)
+                mkFloat(v, stod(tmp_number));
+            else
+                mkInt(v, stoi(tmp_number));
+        } catch (std::invalid_argument e) {
+            throw JSONParseError("invalid JSON number");
+        } catch (std::out_of_range e) {
+            throw JSONParseError("out-of-range JSON number");
+        }
     }
 
     else if (strncmp(s, "true", 4) == 0) {

src/libexpr/lexer.l

@@ -49,9 +49,10 @@ static void adjustLoc(YYLTYPE * loc, const char * s, size_t len)
 }
 
 
-static Expr * unescapeStr(SymbolTable & symbols, const char * s)
+static Expr * unescapeStr(SymbolTable & symbols, const char * s, size_t length)
 {
     string t;
+    t.reserve(length);
     char c;
     while ((c = *s++)) {
         if (c == '\\') {
@@ -124,13 +125,13 @@ or          { return OR_KW; }
 {INT}       { errno = 0;
               yylval->n = strtol(yytext, 0, 10);
               if (errno != 0)
-                  throw ParseError(format("invalid integer ‘%1%’") % yytext);
+                  throw ParseError(format("invalid integer '%1%'") % yytext);
               return INT;
             }
 {FLOAT}     { errno = 0;
               yylval->nf = strtod(yytext, 0);
               if (errno != 0)
-                  throw ParseError(format("invalid float ‘%1%’") % yytext);
+                  throw ParseError(format("invalid float '%1%'") % yytext);
               return FLOAT;
             }
 
@@ -150,7 +151,7 @@ or          { return OR_KW; }
                 /* It is impossible to match strings ending with '$' with one
                    regex because trailing contexts are only valid at the end
                    of a rule. (A sane but undocumented limitation.) */
-                yylval->e = unescapeStr(data->symbols, yytext);
+                yylval->e = unescapeStr(data->symbols, yytext, yyleng);
                 return STR;
               }
 <STRING>\$\{  { PUSH_STATE(INSIDE_DOLLAR_CURLY); return DOLLAR_CURLY; }
@@ -178,7 +179,7 @@ or          { return OR_KW; }
                    return IND_STR;
                  }
 <IND_STRING>\'\'\\. {
-                   yylval->e = unescapeStr(data->symbols, yytext + 2);
+                   yylval->e = unescapeStr(data->symbols, yytext + 2, yyleng - 2);
                    return IND_STR;
                  }
 <IND_STRING>\$\{ { PUSH_STATE(INSIDE_DOLLAR_CURLY); return DOLLAR_CURLY; }
@@ -191,12 +192,12 @@ or          { return OR_KW; }
 <INITIAL,INSIDE_DOLLAR_CURLY>{
 
 {PATH}      { if (yytext[yyleng-1] == '/')
-                  throw ParseError("path ‘%s’ has a trailing slash", yytext);
+                  throw ParseError("path '%s' has a trailing slash", yytext);
               yylval->path = strdup(yytext);
               return PATH;
             }
 {HPATH}     { if (yytext[yyleng-1] == '/')
-                  throw ParseError("path ‘%s’ has a trailing slash", yytext);
+                  throw ParseError("path '%s' has a trailing slash", yytext);
               yylval->path = strdup(yytext);
               return HPATH;
             }

src/libexpr/names.cc

@@ -41,7 +41,7 @@ bool DrvName::matches(DrvName & n)
 }
 
 
-static string nextComponent(string::const_iterator & p,
+string nextComponent(string::const_iterator & p,
     const string::const_iterator end)
 {
     /* Skip any dots and dashes (component separators). */

src/libexpr/names.hh

@@ -24,6 +24,8 @@ private:
 
 typedef list<DrvName> DrvNames;
 
+string nextComponent(string::const_iterator & p,
+    const string::const_iterator end);
 int compareVersions(const string & v1, const string & v2);
 DrvNames drvNamesFromArgs(const Strings & opArgs);
 

src/libexpr/nix-expr.pc.in

@@ -7,4 +7,4 @@ Description: Nix Package Manager
 Version: @PACKAGE_VERSION@
 Requires: nix-store bdw-gc
 Libs: -L${libdir} -lnixexpr
-Cflags: -I${includedir}/nix
+Cflags: -I${includedir}/nix -std=c++14

src/libexpr/nixexpr.cc

@@ -267,7 +267,7 @@ void ExprVar::bindVars(const StaticEnv & env)
     /* Otherwise, the variable must be obtained from the nearest
        enclosing `with'.  If there is no `with', then we can issue an
        "undefined variable" error now. */
-    if (withLevel == -1) throw UndefinedVarError(format("undefined variable ‘%1%’ at %2%") % name % pos);
+    if (withLevel == -1) throw UndefinedVarError(format("undefined variable '%1%' at %2%") % name % pos);
 
     fromWith = true;
     this->level = withLevel;
@@ -419,7 +419,7 @@ void ExprLambda::setName(Symbol & name)
 
 string ExprLambda::showNamePos() const
 {
-    return (format("%1% at %2%") % (name.set() ? "‘" + (string) name + "’" : "anonymous function") % pos).str();
+    return (format("%1% at %2%") % (name.set() ? "'" + (string) name + "'" : "anonymous function") % pos).str();
 }
 
 

src/libexpr/nixexpr.hh

@@ -235,7 +235,7 @@ struct ExprLambda : Expr
         : pos(pos), arg(arg), matchAttrs(matchAttrs), formals(formals), body(body)
     {
         if (!arg.empty() && formals && formals->argNames.find(arg) != formals->argNames.end())
-            throw ParseError(format("duplicate formal function argument ‘%1%’ at %2%")
+            throw ParseError(format("duplicate formal function argument '%1%' at %2%")
                 % arg % pos);
     };
     void setName(Symbol & name);

src/libexpr/parser.y

@@ -65,14 +65,14 @@ namespace nix {
 
 static void dupAttr(const AttrPath & attrPath, const Pos & pos, const Pos & prevPos)
 {
-    throw ParseError(format("attribute ‘%1%’ at %2% already defined at %3%")
+    throw ParseError(format("attribute '%1%' at %2% already defined at %3%")
         % showAttrPath(attrPath) % pos % prevPos);
 }
 
 
 static void dupAttr(Symbol attr, const Pos & pos, const Pos & prevPos)
 {
-    throw ParseError(format("attribute ‘%1%’ at %2% already defined at %3%")
+    throw ParseError(format("attribute '%1%' at %2% already defined at %3%")
         % attr % pos % prevPos);
 }
 
@@ -121,7 +121,7 @@ static void addAttr(ExprAttrs * attrs, AttrPath & attrPath,
 static void addFormal(const Pos & pos, Formals * formals, const Formal & formal)
 {
     if (formals->argNames.find(formal.name) != formals->argNames.end())
-        throw ParseError(format("duplicate formal function argument ‘%1%’ at %2%")
+        throw ParseError(format("duplicate formal function argument '%1%' at %2%")
             % formal.name % pos);
     formals->formals.push_front(formal);
     formals->argNames.insert(formal.name);
@@ -523,7 +523,6 @@ formal
 #include "eval.hh"
 #include "download.hh"
 #include "store-api.hh"
-#include "primops/fetchgit.hh"
 
 
 namespace nix {
@@ -564,7 +563,7 @@ Path resolveExprPath(Path path)
     struct stat st;
     while (true) {
         if (lstat(path.c_str(), &st))
-            throw SysError(format("getting status of ‘%1%’") % path);
+            throw SysError(format("getting status of '%1%'") % path);
         if (!S_ISLNK(st.st_mode)) break;
         path = absPath(readLink(path), dirOf(path));
     }
@@ -601,6 +600,13 @@ Expr * EvalState::parseExprFromString(const string & s, const Path & basePath)
 }
 
 
+Expr * EvalState::parseStdin()
+{
+    //Activity act(*logger, lvlTalkative, format("parsing standard input"));
+    return parseExprFromString(drainFD(0), absPath("."));
+}
+
+
 void EvalState::addToSearchPath(const string & s)
 {
     size_t pos = s.find('=');
@@ -642,7 +648,7 @@ Path EvalState::findFile(SearchPath & searchPath, const string & path, const Pos
         if (pathExists(res)) return canonPath(res);
     }
     format f = format(
-        "file ‘%1%’ was not found in the Nix search path (add it using $NIX_PATH or -I)"
+        "file '%1%' was not found in the Nix search path (add it using $NIX_PATH or -I)"
         + string(pos ? ", at %2%" : ""));
     f.exceptions(boost::io::all_error_bits ^ boost::io::too_many_args_bit);
     throw ThrownError(f % path % pos);
@@ -658,13 +664,9 @@ std::pair<bool, std::string> EvalState::resolveSearchPathElem(const SearchPathEl
 
     if (isUri(elem.second)) {
         try {
-            if (hasPrefix(elem.second, "git://") || hasSuffix(elem.second, ".git"))
-                // FIXME: support specifying revision/branch
-                res = { true, exportGit(store, elem.second, "master") };
-            else
-                res = { true, getDownloader()->downloadCached(store, elem.second, true) };
+            res = { true, getDownloader()->downloadCached(store, elem.second, true) };
         } catch (DownloadError & e) {
-            printError(format("warning: Nix search path entry ‘%1%’ cannot be downloaded, ignoring") % elem.second);
+            printError(format("warning: Nix search path entry '%1%' cannot be downloaded, ignoring") % elem.second);
             res = { false, "" };
         }
     } else {
@@ -672,12 +674,12 @@ std::pair<bool, std::string> EvalState::resolveSearchPathElem(const SearchPathEl
         if (pathExists(path))
             res = { true, path };
         else {
-            printError(format("warning: Nix search path entry ‘%1%’ does not exist, ignoring") % elem.second);
+            printError(format("warning: Nix search path entry '%1%' does not exist, ignoring") % elem.second);
             res = { false, "" };
         }
     }
 
-    debug(format("resolved search path element ‘%s’ to ‘%s’") % elem.second % res.second);
+    debug(format("resolved search path element '%s' to '%s'") % elem.second % res.second);
 
     searchPathResolved[elem.second] = res;
     return res;

src/libexpr/primops.cc

@@ -39,34 +39,48 @@ std::pair<string, string> decodeContext(const string & s)
         size_t index = s.find("!", 1);
         return std::pair<string, string>(string(s, index + 1), string(s, 1, index - 1));
     } else
-        return std::pair<string, string>(s.at(0) == '/' ? s: string(s, 1), "");
+        return std::pair<string, string>(s.at(0) == '/' ? s : string(s, 1), "");
 }
 
 
 InvalidPathError::InvalidPathError(const Path & path) :
-    EvalError(format("path ‘%1%’ is not valid") % path), path(path) {}
+    EvalError(format("path '%1%' is not valid") % path), path(path) {}
 
 void EvalState::realiseContext(const PathSet & context)
 {
     PathSet drvs;
+
     for (auto & i : context) {
         std::pair<string, string> decoded = decodeContext(i);
         Path ctx = decoded.first;
         assert(store->isStorePath(ctx));
         if (!store->isValidPath(ctx))
             throw InvalidPathError(ctx);
-        if (!decoded.second.empty() && nix::isDerivation(ctx))
+        if (!decoded.second.empty() && nix::isDerivation(ctx)) {
             drvs.insert(decoded.first + "!" + decoded.second);
+
+            /* Add the output of this derivation to the allowed
+               paths. */
+            if (allowedPaths) {
+                auto drv = store->derivationFromPath(decoded.first);
+                DerivationOutputs::iterator i = drv.outputs.find(decoded.second);
+                if (i == drv.outputs.end())
+                    throw Error("derivation '%s' does not have an output named '%s'", decoded.first, decoded.second);
+                allowedPaths->insert(i->second.path);
+            }
+        }
     }
-    if (!drvs.empty()) {
-        if (!settings.enableImportFromDerivation)
-            throw EvalError(format("attempted to realize ‘%1%’ during evaluation but 'allow-import-from-derivation' is false") % *(drvs.begin()));
-        /* For performance, prefetch all substitute info. */
-        PathSet willBuild, willSubstitute, unknown;
-        unsigned long long downloadSize, narSize;
-        store->queryMissing(drvs, willBuild, willSubstitute, unknown, downloadSize, narSize);
-        store->buildPaths(drvs);
-    }
+
+    if (drvs.empty()) return;
+
+    if (!settings.enableImportFromDerivation)
+        throw EvalError(format("attempted to realize '%1%' during evaluation but 'allow-import-from-derivation' is false") % *(drvs.begin()));
+
+    /* For performance, prefetch all substitute info. */
+    PathSet willBuild, willSubstitute, unknown;
+    unsigned long long downloadSize, narSize;
+    store->queryMissing(drvs, willBuild, willSubstitute, unknown, downloadSize, narSize);
+    store->buildPaths(drvs);
 }
 
 
@@ -80,14 +94,14 @@ static void prim_scopedImport(EvalState & state, const Pos & pos, Value * * args
     try {
         state.realiseContext(context);
     } catch (InvalidPathError & e) {
-        throw EvalError(format("cannot import ‘%1%’, since path ‘%2%’ is not valid, at %3%")
+        throw EvalError(format("cannot import '%1%', since path '%2%' is not valid, at %3%")
             % path % e.path % pos);
     }
 
-    path = state.checkSourcePath(path);
+    Path realPath = state.checkSourcePath(state.toRealPath(path, context));
 
     if (state.store->isStorePath(path) && state.store->isValidPath(path) && isDerivation(path)) {
-        Derivation drv = readDerivation(path);
+        Derivation drv = readDerivation(realPath);
         Value & w = *state.allocValue();
         state.mkAttrs(w, 3 + drv.outputs.size());
         Value * v2 = state.allocAttr(w, state.sDrvPath);
@@ -114,7 +128,7 @@ static void prim_scopedImport(EvalState & state, const Pos & pos, Value * * args
     } else {
         state.forceAttrs(*args[0]);
         if (args[0]->attrs->empty())
-            state.evalFile(path, v);
+            state.evalFile(realPath, v);
         else {
             Env * env = &state.allocEnv(args[0]->attrs->size());
             env->up = &state.baseEnv;
@@ -127,8 +141,8 @@ static void prim_scopedImport(EvalState & state, const Pos & pos, Value * * args
                 env->values[displ++] = attr.value;
             }
 
-            printTalkative("evaluating file ‘%1%’", path);
-            Expr * e = state.parseExprFromFile(resolveExprPath(path), staticEnv);
+            printTalkative("evaluating file '%1%'", realPath);
+            Expr * e = state.parseExprFromFile(resolveExprPath(realPath), staticEnv);
 
             e->eval(state, *env, v);
         }
@@ -141,7 +155,7 @@ static void prim_scopedImport(EvalState & state, const Pos & pos, Value * * args
 extern "C" typedef void (*ValueInitializer)(EvalState & state, Value & v);
 
 /* Load a ValueInitializer from a DSO and return whatever it initializes */
-static void prim_importNative(EvalState & state, const Pos & pos, Value * * args, Value & v)
+void prim_importNative(EvalState & state, const Pos & pos, Value * * args, Value & v)
 {
     PathSet context;
     Path path = state.coerceToPath(pos, *args[0], context);
@@ -149,7 +163,7 @@ static void prim_importNative(EvalState & state, const Pos & pos, Value * * args
     try {
         state.realiseContext(context);
     } catch (InvalidPathError & e) {
-        throw EvalError(format("cannot import ‘%1%’, since path ‘%2%’ is not valid, at %3%")
+        throw EvalError(format("cannot import '%1%', since path '%2%' is not valid, at %3%")
             % path % e.path % pos);
     }
 
@@ -159,16 +173,16 @@ static void prim_importNative(EvalState & state, const Pos & pos, Value * * args
 
     void *handle = dlopen(path.c_str(), RTLD_LAZY | RTLD_LOCAL);
     if (!handle)
-        throw EvalError(format("could not open ‘%1%’: %2%") % path % dlerror());
+        throw EvalError(format("could not open '%1%': %2%") % path % dlerror());
 
     dlerror();
     ValueInitializer func = (ValueInitializer) dlsym(handle, sym.c_str());
     if(!func) {
         char *message = dlerror();
         if (message)
-            throw EvalError(format("could not load symbol ‘%1%’ from ‘%2%’: %3%") % sym % path % message);
+            throw EvalError(format("could not load symbol '%1%' from '%2%': %3%") % sym % path % message);
         else
-            throw EvalError(format("symbol ‘%1%’ from ‘%2%’ resolved to NULL when a function pointer was expected")
+            throw EvalError(format("symbol '%1%' from '%2%' resolved to NULL when a function pointer was expected")
                     % sym % path);
     }
 
@@ -179,7 +193,7 @@ static void prim_importNative(EvalState & state, const Pos & pos, Value * * args
 
 
 /* Execute a program and parse its output */
-static void prim_exec(EvalState & state, const Pos & pos, Value * * args, Value & v)
+void prim_exec(EvalState & state, const Pos & pos, Value * * args, Value & v)
 {
     state.forceList(*args[0], pos);
     auto elems = args[0]->listElems();
@@ -196,7 +210,7 @@ static void prim_exec(EvalState & state, const Pos & pos, Value * * args, Value
     try {
         state.realiseContext(context);
     } catch (InvalidPathError & e) {
-        throw EvalError(format("cannot execute ‘%1%’, since path ‘%2%’ is not valid, at %3%")
+        throw EvalError(format("cannot execute '%1%', since path '%2%' is not valid, at %3%")
             % program % e.path % pos);
     }
 
@@ -205,13 +219,13 @@ static void prim_exec(EvalState & state, const Pos & pos, Value * * args, Value
     try {
         parsed = state.parseExprFromString(output, pos.file);
     } catch (Error & e) {
-        e.addPrefix(format("While parsing the output from ‘%1%’, at %2%\n") % program % pos);
+        e.addPrefix(format("While parsing the output from '%1%', at %2%\n") % program % pos);
         throw;
     }
     try {
         state.eval(parsed, v);
     } catch (Error & e) {
-        e.addPrefix(format("While evaluating the output from ‘%1%’, at %2%\n") % program % pos);
+        e.addPrefix(format("While evaluating the output from '%1%', at %2%\n") % program % pos);
         throw;
     }
 }
@@ -332,7 +346,7 @@ static void prim_genericClosure(EvalState & state, const Pos & pos, Value * * ar
     Bindings::iterator startSet =
         args[0]->attrs->find(state.symbols.create("startSet"));
     if (startSet == args[0]->attrs->end())
-        throw EvalError(format("attribute ‘startSet’ required, at %1%") % pos);
+        throw EvalError(format("attribute 'startSet' required, at %1%") % pos);
     state.forceList(*startSet->value, pos);
 
     ValueList workSet;
@@ -343,7 +357,7 @@ static void prim_genericClosure(EvalState & state, const Pos & pos, Value * * ar
     Bindings::iterator op =
         args[0]->attrs->find(state.symbols.create("operator"));
     if (op == args[0]->attrs->end())
-        throw EvalError(format("attribute ‘operator’ required, at %1%") % pos);
+        throw EvalError(format("attribute 'operator' required, at %1%") % pos);
     state.forceValue(*op->value);
 
     /* Construct the closure by applying the operator to element of
@@ -362,7 +376,7 @@ static void prim_genericClosure(EvalState & state, const Pos & pos, Value * * ar
         Bindings::iterator key =
             e->attrs->find(state.symbols.create("key"));
         if (key == e->attrs->end())
-            throw EvalError(format("attribute ‘key’ required, at %1%") % pos);
+            throw EvalError(format("attribute 'key' required, at %1%") % pos);
         state.forceValue(*key->value);
 
         if (doneKeys.find(key->value) != doneKeys.end()) continue;
@@ -393,7 +407,7 @@ static void prim_abort(EvalState & state, const Pos & pos, Value * * args, Value
 {
     PathSet context;
     string s = state.coerceToString(pos, *args[0], context);
-    throw Abort(format("evaluation aborted with the following error message: ‘%1%’") % s);
+    throw Abort(format("evaluation aborted with the following error message: '%1%'") % s);
 }
 
 
@@ -439,7 +453,7 @@ static void prim_tryEval(EvalState & state, const Pos & pos, Value * * args, Val
 static void prim_getEnv(EvalState & state, const Pos & pos, Value * * args, Value & v)
 {
     string name = state.forceStringNoCtx(*args[0], pos);
-    mkString(v, state.restricted ? "" : getEnv(name));
+    mkString(v, settings.restrictEval || settings.pureEval ? "" : getEnv(name));
 }
 
 
@@ -502,13 +516,13 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
     /* Figure out the name first (for stack backtraces). */
     Bindings::iterator attr = args[0]->attrs->find(state.sName);
     if (attr == args[0]->attrs->end())
-        throw EvalError(format("required attribute ‘name’ missing, at %1%") % pos);
+        throw EvalError(format("required attribute 'name' missing, at %1%") % pos);
     string drvName;
     Pos & posDrvName(*attr->pos);
     try {
         drvName = state.forceStringNoCtx(*attr->value, pos);
     } catch (Error & e) {
-        e.addPrefix(format("while evaluating the derivation attribute ‘name’ at %1%:\n") % posDrvName);
+        e.addPrefix(format("while evaluating the derivation attribute 'name' at %1%:\n") % posDrvName);
         throw;
     }
 
@@ -539,27 +553,27 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
 
     for (auto & i : args[0]->attrs->lexicographicOrder()) {
         if (i->name == state.sIgnoreNulls) continue;
-        string key = i->name;
-        vomit("processing attribute ‘%1%’", key);
+        const string & key = i->name;
+        vomit("processing attribute '%1%'", key);
 
         auto handleHashMode = [&](const std::string & s) {
             if (s == "recursive") outputHashRecursive = true;
             else if (s == "flat") outputHashRecursive = false;
-            else throw EvalError("invalid value ‘%s’ for ‘outputHashMode’ attribute, at %s", s, posDrvName);
+            else throw EvalError("invalid value '%s' for 'outputHashMode' attribute, at %s", s, posDrvName);
         };
 
         auto handleOutputs = [&](const Strings & ss) {
             outputs.clear();
             for (auto & j : ss) {
                 if (outputs.find(j) != outputs.end())
-                    throw EvalError(format("duplicate derivation output ‘%1%’, at %2%") % j % posDrvName);
+                    throw EvalError(format("duplicate derivation output '%1%', at %2%") % j % posDrvName);
                 /* !!! Check whether j is a valid attribute
                    name. */
                 /* Derivations cannot be named ‘drv’, because
                    then we'd have an attribute ‘drvPath’ in
                    the resulting set. */
                 if (j == "drv")
-                    throw EvalError(format("invalid derivation output name ‘drv’, at %1%") % posDrvName);
+                    throw EvalError(format("invalid derivation output name 'drv', at %1%") % posDrvName);
                 outputs.insert(j);
             }
             if (outputs.empty())
@@ -575,7 +589,7 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
 
             /* The `args' attribute is special: it supplies the
                command-line arguments to the builder. */
-            if (key == "args") {
+            if (i->name == state.sArgs) {
                 state.forceList(*i->value, pos);
                 for (unsigned int n = 0; n < i->value->listSize(); ++n) {
                     string s = state.coerceToString(posDrvName, *i->value->listElems()[n], context, true);
@@ -598,15 +612,13 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
                         drv.builder = state.forceString(*i->value, context, posDrvName);
                     else if (i->name == state.sSystem)
                         drv.platform = state.forceStringNoCtx(*i->value, posDrvName);
-                    else if (i->name == state.sName)
-                        drvName = state.forceStringNoCtx(*i->value, posDrvName);
-                    else if (key == "outputHash")
+                    else if (i->name == state.sOutputHash)
                         outputHash = state.forceStringNoCtx(*i->value, posDrvName);
-                    else if (key == "outputHashAlgo")
+                    else if (i->name == state.sOutputHashAlgo)
                         outputHashAlgo = state.forceStringNoCtx(*i->value, posDrvName);
-                    else if (key == "outputHashMode")
+                    else if (i->name == state.sOutputHashMode)
                         handleHashMode(state.forceStringNoCtx(*i->value, posDrvName));
-                    else if (key == "outputs") {
+                    else if (i->name == state.sOutputs) {
                         /* Require ‘outputs’ to be a list of strings. */
                         state.forceList(*i->value, posDrvName);
                         Strings ss;
@@ -620,21 +632,17 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
                     drv.env.emplace(key, s);
                     if (i->name == state.sBuilder) drv.builder = s;
                     else if (i->name == state.sSystem) drv.platform = s;
-                    else if (i->name == state.sName) {
-                        drvName = s;
-                        printMsg(lvlVomit, format("derivation name is ‘%1%’") % drvName);
-                    }
-                    else if (key == "outputHash") outputHash = s;
-                    else if (key == "outputHashAlgo") outputHashAlgo = s;
-                    else if (key == "outputHashMode") handleHashMode(s);
-                    else if (key == "outputs")
+                    else if (i->name == state.sOutputHash) outputHash = s;
+                    else if (i->name == state.sOutputHashAlgo) outputHashAlgo = s;
+                    else if (i->name == state.sOutputHashMode) handleHashMode(s);
+                    else if (i->name == state.sOutputs)
                         handleOutputs(tokenizeString<Strings>(s));
                 }
 
             }
 
         } catch (Error & e) {
-            e.addPrefix(format("while evaluating the attribute ‘%1%’ of the derivation ‘%2%’ at %3%:\n")
+            e.addPrefix(format("while evaluating the attribute '%1%' of the derivation '%2%' at %3%:\n")
                 % key % drvName % posDrvName);
             throw;
         }
@@ -690,14 +698,14 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
 
     /* Do we have all required attributes? */
     if (drv.builder == "")
-        throw EvalError(format("required attribute ‘builder’ missing, at %1%") % posDrvName);
+        throw EvalError(format("required attribute 'builder' missing, at %1%") % posDrvName);
     if (drv.platform == "")
-        throw EvalError(format("required attribute ‘system’ missing, at %1%") % posDrvName);
+        throw EvalError(format("required attribute 'system' missing, at %1%") % posDrvName);
 
     /* Check whether the derivation name is valid. */
     checkStoreName(drvName);
     if (isDerivation(drvName))
-        throw EvalError(format("derivation names are not allowed to end in ‘%1%’, at %2%")
+        throw EvalError(format("derivation names are not allowed to end in '%1%', at %2%")
             % drvExtension % posDrvName);
 
     if (outputHash) {
@@ -707,13 +715,13 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
 
         HashType ht = parseHashType(outputHashAlgo);
         if (ht == htUnknown)
-            throw EvalError(format("unknown hash algorithm ‘%1%’, at %2%") % outputHashAlgo % posDrvName);
-        Hash h = parseHash16or32(ht, *outputHash);
-        outputHash = printHash(h);
+            throw EvalError(format("unknown hash algorithm '%1%', at %2%") % outputHashAlgo % posDrvName);
+        Hash h(*outputHash, ht);
+        outputHash = h.to_string(Base16, false);
         if (outputHashRecursive) outputHashAlgo = "r:" + outputHashAlgo;
 
         Path outPath = state.store->makeFixedOutputPath(outputHashRecursive, h, drvName);
-        drv.env["out"] = outPath;
+        if (!jsonObject) drv.env["out"] = outPath;
         drv.outputs["out"] = DerivationOutput(outPath, outputHashAlgo, *outputHash);
     }
 
@@ -724,7 +732,7 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
            an empty value.  This ensures that changes in the set of
            output names do get reflected in the hash. */
         for (auto & i : outputs) {
-            drv.env[i] = "";
+            if (!jsonObject) drv.env[i] = "";
             drv.outputs[i] = DerivationOutput("", "", "");
         }
 
@@ -735,7 +743,7 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
         for (auto & i : drv.outputs)
             if (i.second.path == "") {
                 Path outPath = state.store->makeOutputPath(i.first, h, drvName);
-                drv.env[i.first] = outPath;
+                if (!jsonObject) drv.env[i.first] = outPath;
                 i.second.path = outPath;
             }
     }
@@ -743,7 +751,7 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
     /* Write the resulting term into the Nix store directory. */
     Path drvPath = writeDerivation(state.store, drv, drvName, state.repair);
 
-    printMsg(lvlChatty, format("instantiated ‘%1%’ -> ‘%2%’")
+    printMsg(lvlChatty, format("instantiated '%1%' -> '%2%'")
         % drvName % drvPath);
 
     /* Optimisation, but required in read-only mode! because in that
@@ -763,7 +771,7 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
 
 /* Return a placeholder string for the specified output that will be
    substituted by the corresponding output path at build time. For
-   example, ‘placeholder "out"’ returns the string
+   example, 'placeholder "out"' returns the string
    /1rz4g4znpzjwh1xymhjpm42vipw92pr73vdgl6xs1hycac8kf2n9. At build
    time, any occurence of this string in an derivation attribute will
    be replaced with the concrete path in the Nix store of the output
@@ -805,7 +813,7 @@ static void prim_storePath(EvalState & state, const Pos & pos, Value * * args, V
        e.g. nix-push does the right thing. */
     if (!state.store->isStorePath(path)) path = canonPath(path, true);
     if (!state.store->isInStore(path))
-        throw EvalError(format("path ‘%1%’ is not in the Nix store, at %2%") % path % pos);
+        throw EvalError(format("path '%1%' is not in the Nix store, at %2%") % path % pos);
     Path path2 = state.store->toStorePath(path);
     if (!settings.readOnlyMode)
         state.store->ensurePath(path2);
@@ -819,7 +827,7 @@ static void prim_pathExists(EvalState & state, const Pos & pos, Value * * args,
     PathSet context;
     Path path = state.coerceToPath(pos, *args[0], context);
     if (!context.empty())
-        throw EvalError(format("string ‘%1%’ cannot refer to other paths, at %2%") % path % pos);
+        throw EvalError(format("string '%1%' cannot refer to other paths, at %2%") % path % pos);
     try {
         mkBool(v, pathExists(state.checkSourcePath(path)));
     } catch (SysError & e) {
@@ -860,18 +868,18 @@ static void prim_readFile(EvalState & state, const Pos & pos, Value * * args, Va
     try {
         state.realiseContext(context);
     } catch (InvalidPathError & e) {
-        throw EvalError(format("cannot read ‘%1%’, since path ‘%2%’ is not valid, at %3%")
+        throw EvalError(format("cannot read '%1%', since path '%2%' is not valid, at %3%")
             % path % e.path % pos);
     }
-    string s = readFile(state.checkSourcePath(path));
+    string s = readFile(state.checkSourcePath(state.toRealPath(path, context)));
     if (s.find((char) 0) != string::npos)
-        throw Error(format("the contents of the file ‘%1%’ cannot be represented as a Nix string") % path);
+        throw Error(format("the contents of the file '%1%' cannot be represented as a Nix string") % path);
     mkString(v, s.c_str());
 }
 
 
 /* Find a file in the Nix search path. Used to implement <x> paths,
-   which are desugared to ‘findFile __nixPath "x"’. */
+   which are desugared to 'findFile __nixPath "x"'. */
 static void prim_findFile(EvalState & state, const Pos & pos, Value * * args, Value & v)
 {
     state.forceList(*args[0], pos);
@@ -889,7 +897,7 @@ static void prim_findFile(EvalState & state, const Pos & pos, Value * * args, Va
 
         i = v2.attrs->find(state.symbols.create("path"));
         if (i == v2.attrs->end())
-            throw EvalError(format("attribute ‘path’ missing, at %1%") % pos);
+            throw EvalError(format("attribute 'path' missing, at %1%") % pos);
 
         PathSet context;
         string path = state.coerceToString(pos, *i->value, context, false, false);
@@ -897,7 +905,7 @@ static void prim_findFile(EvalState & state, const Pos & pos, Value * * args, Va
         try {
             state.realiseContext(context);
         } catch (InvalidPathError & e) {
-            throw EvalError(format("cannot find ‘%1%’, since path ‘%2%’ is not valid, at %3%")
+            throw EvalError(format("cannot find '%1%', since path '%2%' is not valid, at %3%")
                 % path % e.path % pos);
         }
 
@@ -917,7 +925,7 @@ static void prim_readDir(EvalState & state, const Pos & pos, Value * * args, Val
     try {
         state.realiseContext(ctx);
     } catch (InvalidPathError & e) {
-        throw EvalError(format("cannot read ‘%1%’, since path ‘%2%’ is not valid, at %3%")
+        throw EvalError(format("cannot read '%1%', since path '%2%' is not valid, at %3%")
             % path % e.path % pos);
     }
 
@@ -991,7 +999,7 @@ static void prim_toFile(EvalState & state, const Pos & pos, Value * * args, Valu
         if (isDerivation(path)) {
             /* See prim_unsafeDiscardOutputDependency. */
             if (path.at(0) != '~')
-                throw EvalError(format("in ‘toFile’: the file ‘%1%’ cannot refer to derivation outputs, at %2%") % name % pos);
+                throw EvalError(format("in 'toFile': the file '%1%' cannot refer to derivation outputs, at %2%") % name % pos);
             path = string(path, 1);
         }
         refs.insert(path);
@@ -1009,22 +1017,14 @@ static void prim_toFile(EvalState & state, const Pos & pos, Value * * args, Valu
 }
 
 
-struct FilterFromExpr : PathFilter
+static void addPath(EvalState & state, const Pos & pos, const string & name, const Path & path_,
+    Value * filterFun, bool recursive, const Hash & expectedHash, Value & v)
 {
-    EvalState & state;
-    Value & filter;
-    Pos pos;
-
-    FilterFromExpr(EvalState & state, Value & filter, const Pos & pos)
-        : state(state), filter(filter), pos(pos)
-    {
-    }
-
-    bool operator () (const Path & path)
-    {
-        struct stat st;
-        if (lstat(path.c_str(), &st))
-            throw SysError(format("getting attributes of path ‘%1%’") % path);
+    const auto path = settings.pureEval && expectedHash ?
+        path_ :
+        state.checkSourcePath(path_);
+    PathFilter filter = filterFun ? ([&](const Path & path) {
+        auto st = lstat(path);
 
         /* Call the filter function.  The first argument is the path,
            the second is a string indicating the type of the file. */
@@ -1032,7 +1032,7 @@ struct FilterFromExpr : PathFilter
         mkString(arg1, path);
 
         Value fun2;
-        state.callFunction(filter, arg1, fun2, noPos);
+        state.callFunction(*filterFun, arg1, fun2, noPos);
 
         Value arg2;
         mkString(arg2,
@@ -1045,8 +1045,26 @@ struct FilterFromExpr : PathFilter
         state.callFunction(fun2, arg2, res, noPos);
 
         return state.forceBool(res, pos);
+    }) : defaultPathFilter;
+
+    Path expectedStorePath;
+    if (expectedHash) {
+        expectedStorePath =
+            state.store->makeFixedOutputPath(recursive, expectedHash, name);
     }
-};
+    Path dstPath;
+    if (!expectedHash || !state.store->isValidPath(expectedStorePath)) {
+        dstPath = settings.readOnlyMode
+            ? state.store->computeStorePathForPath(name, path, recursive, htSHA256, filter).first
+            : state.store->addToStore(name, path, recursive, htSHA256, filter, state.repair);
+        if (expectedHash && expectedStorePath != dstPath) {
+            throw Error(format("store path mismatch in (possibly filtered) path added from '%1%'") % path);
+        }
+    } else
+        dstPath = expectedStorePath;
+
+    mkString(v, dstPath, {dstPath});
+}
 
 
 static void prim_filterSource(EvalState & state, const Pos & pos, Value * * args, Value & v)
@@ -1054,21 +1072,49 @@ static void prim_filterSource(EvalState & state, const Pos & pos, Value * * args
     PathSet context;
     Path path = state.coerceToPath(pos, *args[1], context);
     if (!context.empty())
-        throw EvalError(format("string ‘%1%’ cannot refer to other paths, at %2%") % path % pos);
+        throw EvalError(format("string '%1%' cannot refer to other paths, at %2%") % path % pos);
 
     state.forceValue(*args[0]);
     if (args[0]->type != tLambda)
-        throw TypeError(format("first argument in call to ‘filterSource’ is not a function but %1%, at %2%") % showType(*args[0]) % pos);
+        throw TypeError(format("first argument in call to 'filterSource' is not a function but %1%, at %2%") % showType(*args[0]) % pos);
 
-    FilterFromExpr filter(state, *args[0], pos);
+    addPath(state, pos, baseNameOf(path), path, args[0], true, Hash(), v);
+}
 
-    path = state.checkSourcePath(path);
+static void prim_path(EvalState & state, const Pos & pos, Value * * args, Value & v)
+{
+    state.forceAttrs(*args[0], pos);
+    Path path;
+    string name;
+    Value * filterFun = nullptr;
+    auto recursive = true;
+    Hash expectedHash;
 
-    Path dstPath = settings.readOnlyMode
-        ? state.store->computeStorePathForPath(path, true, htSHA256, filter).first
-        : state.store->addToStore(baseNameOf(path), path, true, htSHA256, filter, state.repair);
+    for (auto & attr : *args[0]->attrs) {
+        const string & n(attr.name);
+        if (n == "path") {
+            PathSet context;
+            path = state.coerceToPath(*attr.pos, *attr.value, context);
+            if (!context.empty())
+                throw EvalError(format("string '%1%' cannot refer to other paths, at %2%") % path % *attr.pos);
+        } else if (attr.name == state.sName)
+            name = state.forceStringNoCtx(*attr.value, *attr.pos);
+        else if (n == "filter") {
+            state.forceValue(*attr.value);
+            filterFun = attr.value;
+        } else if (n == "recursive")
+            recursive = state.forceBool(*attr.value, *attr.pos);
+        else if (n == "sha256")
+            expectedHash = Hash(state.forceStringNoCtx(*attr.value, *attr.pos), htSHA256);
+        else
+            throw EvalError(format("unsupported argument '%1%' to 'addPath', at %2%") % attr.name % *attr.pos);
+    }
+    if (path.empty())
+        throw EvalError(format("'path' required, at %1%") % pos);
+    if (name.empty())
+        name = baseNameOf(path);
 
-    mkString(v, dstPath, {dstPath});
+    addPath(state, pos, name, path, filterFun, recursive, expectedHash, v);
 }
 
 
@@ -1086,8 +1132,11 @@ static void prim_attrNames(EvalState & state, const Pos & pos, Value * * args, V
     state.mkList(v, args[0]->attrs->size());
 
     size_t n = 0;
-    for (auto & i : args[0]->attrs->lexicographicOrder())
-        mkString(*(v.listElems()[n++] = state.allocValue()), i->name);
+    for (auto & i : *args[0]->attrs)
+        mkString(*(v.listElems()[n++] = state.allocValue()), i.name);
+
+    std::sort(v.listElems(), v.listElems() + n,
+              [](Value * v1, Value * v2) { return strcmp(v1->string.s, v2->string.s) < 0; });
 }
 
 
@@ -1119,7 +1168,7 @@ void prim_getAttr(EvalState & state, const Pos & pos, Value * * args, Value & v)
     // !!! Should we create a symbol here or just do a lookup?
     Bindings::iterator i = args[1]->attrs->find(state.symbols.create(attr));
     if (i == args[1]->attrs->end())
-        throw EvalError(format("attribute ‘%1%’ missing, at %2%") % attr % pos);
+        throw EvalError(format("attribute '%1%' missing, at %2%") % attr % pos);
     // !!! add to stack trace?
     if (state.countCalls && i->pos) state.attrSelects[*i->pos]++;
     state.forceValue(*i->value);
@@ -1199,14 +1248,14 @@ static void prim_listToAttrs(EvalState & state, const Pos & pos, Value * * args,
 
         Bindings::iterator j = v2.attrs->find(state.sName);
         if (j == v2.attrs->end())
-            throw TypeError(format("‘name’ attribute missing in a call to ‘listToAttrs’, at %1%") % pos);
+            throw TypeError(format("'name' attribute missing in a call to 'listToAttrs', at %1%") % pos);
         string name = state.forceStringNoCtx(*j->value, pos);
 
         Symbol sym = state.symbols.create(name);
         if (seen.find(sym) == seen.end()) {
             Bindings::iterator j2 = v2.attrs->find(state.symbols.create(state.sValue));
             if (j2 == v2.attrs->end())
-                throw TypeError(format("‘value’ attribute missing in a call to ‘listToAttrs’, at %1%") % pos);
+                throw TypeError(format("'value' attribute missing in a call to 'listToAttrs', at %1%") % pos);
 
             v.attrs->push_back(Attr(sym, j2->value, j2->pos));
             seen.insert(sym);
@@ -1281,7 +1330,7 @@ static void prim_functionArgs(EvalState & state, const Pos & pos, Value * * args
 {
     state.forceValue(*args[0]);
     if (args[0]->type != tLambda)
-        throw TypeError(format("‘functionArgs’ requires a function, at %1%") % pos);
+        throw TypeError(format("'functionArgs' requires a function, at %1%") % pos);
 
     if (!args[0]->lambda.fun->matchAttrs) {
         state.mkAttrs(v, 0);
@@ -1340,7 +1389,7 @@ static void prim_tail(EvalState & state, const Pos & pos, Value * * args, Value
 {
     state.forceList(*args[0], pos);
     if (args[0]->listSize() == 0)
-        throw Error(format("‘tail’ called on an empty list, at %1%") % pos);
+        throw Error(format("'tail' called on an empty list, at %1%") % pos);
     state.mkList(v, args[0]->listSize() - 1);
     for (unsigned int n = 0; n < v.listSize(); ++n)
         v.listElems()[n] = args[0]->listElems()[n + 1];
@@ -1649,7 +1698,7 @@ static void prim_substring(EvalState & state, const Pos & pos, Value * * args, V
     PathSet context;
     string s = state.coerceToString(pos, *args[2], context);
 
-    if (start < 0) throw EvalError(format("negative start position in ‘substring’, at %1%") % pos);
+    if (start < 0) throw EvalError(format("negative start position in 'substring', at %1%") % pos);
 
     mkString(v, (unsigned int) start >= s.size() ? "" : string(s, start, len), context);
 }
@@ -1671,6 +1720,14 @@ static void prim_unsafeDiscardStringContext(EvalState & state, const Pos & pos,
 }
 
 
+static void prim_hasContext(EvalState & state, const Pos & pos, Value * * args, Value & v)
+{
+    PathSet context;
+    state.forceString(*args[0], context, pos);
+    mkBool(v, !context.empty());
+}
+
+
 /* Sometimes we want to pass a derivation path (i.e. pkg.drvPath) to a
    builder without causing the derivation to be built (for instance,
    in the derivation that builds NARs in nix-push, when doing
@@ -1696,12 +1753,12 @@ static void prim_hashString(EvalState & state, const Pos & pos, Value * * args,
     string type = state.forceStringNoCtx(*args[0], pos);
     HashType ht = parseHashType(type);
     if (ht == htUnknown)
-      throw Error(format("unknown hash type ‘%1%’, at %2%") % type % pos);
+      throw Error(format("unknown hash type '%1%', at %2%") % type % pos);
 
     PathSet context; // discarded
     string s = state.forceString(*args[1], context, pos);
 
-    mkString(v, printHash(hashString(ht, s)), context);
+    mkString(v, hashString(ht, s).to_string(Base16, false), context);
 }
 
 
@@ -1734,8 +1791,80 @@ static void prim_match(EvalState & state, const Pos & pos, Value * * args, Value
                 mkString(*(v.listElems()[i] = state.allocValue()), match[i + 1].str().c_str());
         }
 
-    } catch (std::regex_error &) {
-        throw EvalError("invalid regular expression ‘%s’, at %s", re, pos);
+    } catch (std::regex_error &e) {
+        if (e.code() == std::regex_constants::error_space) {
+          // limit is _GLIBCXX_REGEX_STATE_LIMIT for libstdc++
+          throw EvalError("memory limit exceeded by regular expression '%s', at %s", re, pos);
+        } else {
+          throw EvalError("invalid regular expression '%s', at %s", re, pos);
+        }
+    }
+}
+
+
+/* Split a string with a regular expression, and return a list of the
+   non-matching parts interleaved by the lists of the matching groups. */
+static void prim_split(EvalState & state, const Pos & pos, Value * * args, Value & v)
+{
+    auto re = state.forceStringNoCtx(*args[0], pos);
+
+    try {
+
+        std::regex regex(re, std::regex::extended);
+
+        PathSet context;
+        const std::string str = state.forceString(*args[1], context, pos);
+
+        auto begin = std::sregex_iterator(str.begin(), str.end(), regex);
+        auto end = std::sregex_iterator();
+
+        // Any matches results are surrounded by non-matching results.
+        const size_t len = std::distance(begin, end);
+        state.mkList(v, 2 * len + 1);
+        size_t idx = 0;
+        Value * elem;
+
+        if (len == 0) {
+            v.listElems()[idx++] = args[1];
+            return;
+        }
+
+        for (std::sregex_iterator i = begin; i != end; ++i) {
+            assert(idx <= 2 * len + 1 - 3);
+            std::smatch match = *i;
+
+            // Add a string for non-matched characters.
+            elem = v.listElems()[idx++] = state.allocValue();
+            mkString(*elem, match.prefix().str().c_str());
+
+            // Add a list for matched substrings.
+            const size_t slen = match.size() - 1;
+            elem = v.listElems()[idx++] = state.allocValue();
+
+            // Start at 1, beacause the first match is the whole string.
+            state.mkList(*elem, slen);
+            for (size_t si = 0; si < slen; ++si) {
+                if (!match[si + 1].matched)
+                    mkNull(*(elem->listElems()[si] = state.allocValue()));
+                else
+                    mkString(*(elem->listElems()[si] = state.allocValue()), match[si + 1].str().c_str());
+            }
+
+            // Add a string for non-matched suffix characters.
+            if (idx == 2 * len) {
+                elem = v.listElems()[idx++] = state.allocValue();
+                mkString(*elem, match.suffix().str().c_str());
+            }
+        }
+        assert(idx == 2 * len + 1);
+
+    } catch (std::regex_error &e) {
+        if (e.code() == std::regex_constants::error_space) {
+          // limit is _GLIBCXX_REGEX_STATE_LIMIT for libstdc++
+          throw EvalError("memory limit exceeded by regular expression '%s', at %s", re, pos);
+        } else {
+          throw EvalError("invalid regular expression '%s', at %s", re, pos);
+        }
     }
 }
 
@@ -1765,7 +1894,7 @@ static void prim_replaceStrings(EvalState & state, const Pos & pos, Value * * ar
     state.forceList(*args[0], pos);
     state.forceList(*args[1], pos);
     if (args[0]->listSize() != args[1]->listSize())
-        throw EvalError(format("‘from’ and ‘to’ arguments to ‘replaceStrings’ have different lengths, at %1%") % pos);
+        throw EvalError(format("'from' and 'to' arguments to 'replaceStrings' have different lengths, at %1%") % pos);
 
     vector<string> from;
     from.reserve(args[0]->listSize());
@@ -1784,21 +1913,32 @@ static void prim_replaceStrings(EvalState & state, const Pos & pos, Value * * ar
     auto s = state.forceString(*args[2], context, pos);
 
     string res;
-    for (size_t p = 0; p < s.size(); ) {
+    // Loops one past last character to handle the case where 'from' contains an empty string.
+    for (size_t p = 0; p <= s.size(); ) {
         bool found = false;
         auto i = from.begin();
         auto j = to.begin();
         for (; i != from.end(); ++i, ++j)
             if (s.compare(p, i->size(), *i) == 0) {
                 found = true;
-                p += i->size();
                 res += j->first;
+                if (i->empty()) {
+                    if (p < s.size())
+                        res += s[p];
+                    p++;
+                } else {
+                    p += i->size();
+                }
                 for (auto& path : j->second)
                     context.insert(path);
                 j->second.clear();
                 break;
             }
-        if (!found) res += s[p++];
+        if (!found) {
+            if (p < s.size())
+                res += s[p];
+            p++;
+        }
     }
 
     mkString(v, res, context);
@@ -1829,17 +1969,37 @@ static void prim_compareVersions(EvalState & state, const Pos & pos, Value * * a
 }
 
 
+static void prim_splitVersion(EvalState & state, const Pos & pos, Value * * args, Value & v)
+{
+    string version = state.forceStringNoCtx(*args[0], pos);
+    auto iter = version.cbegin();
+    Strings components;
+    while (iter != version.cend()) {
+        auto component = nextComponent(iter, version.cend());
+        if (component.empty())
+            break;
+        components.emplace_back(std::move(component));
+    }
+    state.mkList(v, components.size());
+    unsigned int n = 0;
+    for (auto & component : components) {
+        auto listElem = v.listElems()[n++] = state.allocValue();
+        mkString(*listElem, std::move(component));
+    }
+}
+
+
 /*************************************************************
  * Networking
  *************************************************************/
 
 
 void fetch(EvalState & state, const Pos & pos, Value * * args, Value & v,
-    const string & who, bool unpack)
+    const string & who, bool unpack, const std::string & defaultName)
 {
     string url;
     Hash expectedHash;
-    string name;
+    string name = defaultName;
 
     state.forceValue(*args[0]);
 
@@ -1852,36 +2012,42 @@ void fetch(EvalState & state, const Pos & pos, Value * * args, Value & v,
             if (n == "url")
                 url = state.forceStringNoCtx(*attr.value, *attr.pos);
             else if (n == "sha256")
-                expectedHash = parseHash16or32(htSHA256, state.forceStringNoCtx(*attr.value, *attr.pos));
+                expectedHash = Hash(state.forceStringNoCtx(*attr.value, *attr.pos), htSHA256);
             else if (n == "name")
                 name = state.forceStringNoCtx(*attr.value, *attr.pos);
             else
-                throw EvalError(format("unsupported argument ‘%1%’ to ‘%2%’, at %3%") % attr.name % who % attr.pos);
+                throw EvalError(format("unsupported argument '%1%' to '%2%', at %3%") % attr.name % who % attr.pos);
         }
 
         if (url.empty())
-            throw EvalError(format("‘url’ argument required, at %1%") % pos);
+            throw EvalError(format("'url' argument required, at %1%") % pos);
 
     } else
         url = state.forceStringNoCtx(*args[0], pos);
 
-    if (state.restricted && !expectedHash)
-        throw Error(format("‘%1%’ is not allowed in restricted mode") % who);
+    state.checkURI(url);
+
+    if (settings.pureEval && !expectedHash)
+        throw Error("in pure evaluation mode, '%s' requires a 'sha256' argument", who);
 
     Path res = getDownloader()->downloadCached(state.store, url, unpack, name, expectedHash);
+
+    if (state.allowedPaths)
+        state.allowedPaths->insert(res);
+
     mkString(v, res, PathSet({res}));
 }
 
 
 static void prim_fetchurl(EvalState & state, const Pos & pos, Value * * args, Value & v)
 {
-    fetch(state, pos, args, v, "fetchurl", false);
+    fetch(state, pos, args, v, "fetchurl", false, "");
 }
 
 
 static void prim_fetchTarball(EvalState & state, const Pos & pos, Value * * args, Value & v)
 {
-    fetch(state, pos, args, v, "fetchTarball", true);
+    fetch(state, pos, args, v, "fetchTarball", true, "source");
 }
 
 
@@ -1920,11 +2086,24 @@ void EvalState::createBaseEnv()
     mkNull(v);
     addConstant("null", v);
 
-    mkInt(v, time(0));
-    addConstant("__currentTime", v);
+    auto vThrow = addPrimOp("throw", 1, prim_throw);
 
-    mkString(v, settings.thisSystem);
-    addConstant("__currentSystem", v);
+    auto addPurityError = [&](const std::string & name) {
+        Value * v2 = allocValue();
+        mkString(*v2, fmt("'%s' is not allowed in pure evaluation mode", name));
+        mkApp(v, *vThrow, *v2);
+        addConstant(name, v);
+    };
+
+    if (!settings.pureEval) {
+        mkInt(v, time(0));
+        addConstant("__currentTime", v);
+    }
+
+    if (!settings.pureEval) {
+        mkString(v, settings.thisSystem);
+        addConstant("__currentSystem", v);
+    }
 
     mkString(v, nixVersion);
     addConstant("__nixVersion", v);
@@ -1936,14 +2115,14 @@ void EvalState::createBaseEnv()
        language feature gets added.  It's not necessary to increase it
        when primops get added, because you can just use `builtins ?
        primOp' to check. */
-    mkInt(v, 4);
+    mkInt(v, 5);
     addConstant("__langVersion", v);
 
     // Miscellaneous
-    addPrimOp("scopedImport", 2, prim_scopedImport);
+    auto vScopedImport = addPrimOp("scopedImport", 2, prim_scopedImport);
     Value * v2 = allocValue();
     mkAttrs(*v2, 0);
-    mkApp(v, *baseEnv.values[baseEnvDispl - 1], *v2);
+    mkApp(v, *vScopedImport, *v2);
     forceValue(v);
     addConstant("import", v);
     if (settings.enableNativeCode) {
@@ -1959,7 +2138,6 @@ void EvalState::createBaseEnv()
     addPrimOp("__isBool", 1, prim_isBool);
     addPrimOp("__genericClosure", 1, prim_genericClosure);
     addPrimOp("abort", 1, prim_abort);
-    addPrimOp("throw", 1, prim_throw);
     addPrimOp("__addErrorContext", 2, prim_addErrorContext);
     addPrimOp("__tryEval", 1, prim_tryEval);
     addPrimOp("__getEnv", 1, prim_getEnv);
@@ -1974,7 +2152,10 @@ void EvalState::createBaseEnv()
 
     // Paths
     addPrimOp("__toPath", 1, prim_toPath);
-    addPrimOp("__storePath", 1, prim_storePath);
+    if (settings.pureEval)
+        addPurityError("__storePath");
+    else
+        addPrimOp("__storePath", 1, prim_storePath);
     addPrimOp("__pathExists", 1, prim_pathExists);
     addPrimOp("baseNameOf", 1, prim_baseNameOf);
     addPrimOp("dirOf", 1, prim_dirOf);
@@ -1988,6 +2169,7 @@ void EvalState::createBaseEnv()
     addPrimOp("__fromJSON", 1, prim_fromJSON);
     addPrimOp("__toFile", 2, prim_toFile);
     addPrimOp("__filterSource", 2, prim_filterSource);
+    addPrimOp("__path", 1, prim_path);
 
     // Sets
     addPrimOp("__attrNames", 1, prim_attrNames);
@@ -2030,16 +2212,19 @@ void EvalState::createBaseEnv()
     addPrimOp("toString", 1, prim_toString);
     addPrimOp("__substring", 3, prim_substring);
     addPrimOp("__stringLength", 1, prim_stringLength);
+    addPrimOp("__hasContext", 1, prim_hasContext);
     addPrimOp("__unsafeDiscardStringContext", 1, prim_unsafeDiscardStringContext);
     addPrimOp("__unsafeDiscardOutputDependency", 1, prim_unsafeDiscardOutputDependency);
     addPrimOp("__hashString", 2, prim_hashString);
     addPrimOp("__match", 2, prim_match);
+    addPrimOp("__split", 2, prim_split);
     addPrimOp("__concatStringsSep", 2, prim_concatStringSep);
     addPrimOp("__replaceStrings", 3, prim_replaceStrings);
 
     // Versions
     addPrimOp("__parseDrvName", 1, prim_parseDrvName);
     addPrimOp("__compareVersions", 2, prim_compareVersions);
+    addPrimOp("__splitVersion", 1, prim_splitVersion);
 
     // Derivations
     addPrimOp("derivationStrict", 1, prim_derivationStrict);
@@ -2051,7 +2236,7 @@ void EvalState::createBaseEnv()
 
     /* Add a wrapper around the derivation primop that computes the
        `drvPath' and `outPath' attributes lazily. */
-    string path = settings.nixDataDir + "/nix/corepkgs/derivation.nix";
+    string path = canonPath(settings.nixDataDir + "/nix/corepkgs/derivation.nix", true);
     sDerivationNix = symbols.create(path);
     evalFile(path, v);
     addConstant("derivation", v);

src/libexpr/primops.hh

@@ -9,7 +9,18 @@ struct RegisterPrimOp
 {
     typedef std::vector<std::tuple<std::string, size_t, PrimOpFun>> PrimOps;
     static PrimOps * primOps;
+    /* You can register a constant by passing an arity of 0. fun
+       will get called during EvalState initialization, so there
+       may be primops not yet added and builtins is not yet sorted. */
     RegisterPrimOp(std::string name, size_t arity, PrimOpFun fun);
 };
 
+/* These primops are disabled without enableNativeCode, but plugins
+   may wish to use them in limited contexts without globally enabling
+   them. */
+/* Load a ValueInitializer from a DSO and return whatever it initializes */
+void prim_importNative(EvalState & state, const Pos & pos, Value * * args, Value & v);
+/* Execute a program and parse its output */
+void prim_exec(EvalState & state, const Pos & pos, Value * * args, Value & v);
+
 }

src/libexpr/primops/fetchGit.cc

@@ -0,0 +1,243 @@
+#include "primops.hh"
+#include "eval-inline.hh"
+#include "download.hh"
+#include "store-api.hh"
+#include "pathlocks.hh"
+
+#include <sys/time.h>
+
+#include <regex>
+
+#include <nlohmann/json.hpp>
+
+using namespace std::string_literals;
+
+namespace nix {
+
+struct GitInfo
+{
+    Path storePath;
+    std::string rev;
+    std::string shortRev;
+    uint64_t revCount = 0;
+};
+
+std::regex revRegex("^[0-9a-fA-F]{40}$");
+
+GitInfo exportGit(ref<Store> store, const std::string & uri,
+    std::experimental::optional<std::string> ref, std::string rev,
+    const std::string & name)
+{
+    if (settings.pureEval && rev == "")
+        throw Error("in pure evaluation mode, 'fetchGit' requires a Git revision");
+
+    if (!ref && rev == "" && hasPrefix(uri, "/") && pathExists(uri + "/.git")) {
+
+        bool clean = true;
+
+        try {
+            runProgram("git", true, { "-C", uri, "diff-index", "--quiet", "HEAD", "--" });
+        } catch (ExecError e) {
+            if (!WIFEXITED(e.status) || WEXITSTATUS(e.status) != 1) throw;
+            clean = false;
+        }
+
+        if (!clean) {
+
+            /* This is an unclean working tree. So copy all tracked
+               files. */
+
+            GitInfo gitInfo;
+            gitInfo.rev = "0000000000000000000000000000000000000000";
+            gitInfo.shortRev = std::string(gitInfo.rev, 0, 7);
+
+            auto files = tokenizeString<std::set<std::string>>(
+                runProgram("git", true, { "-C", uri, "ls-files", "-z" }), "\0"s);
+
+            PathFilter filter = [&](const Path & p) -> bool {
+                assert(hasPrefix(p, uri));
+                std::string file(p, uri.size() + 1);
+
+                auto st = lstat(p);
+
+                if (S_ISDIR(st.st_mode)) {
+                    auto prefix = file + "/";
+                    auto i = files.lower_bound(prefix);
+                    return i != files.end() && hasPrefix(*i, prefix);
+                }
+
+                return files.count(file);
+            };
+
+            gitInfo.storePath = store->addToStore("source", uri, true, htSHA256, filter);
+
+            return gitInfo;
+        }
+
+        // clean working tree, but no ref or rev specified.  Use 'HEAD'.
+        rev = chomp(runProgram("git", true, { "-C", uri, "rev-parse", "HEAD" }));
+        ref = "HEAD"s;
+    }
+
+    if (!ref) ref = "HEAD"s;
+
+    if (rev != "" && !std::regex_match(rev, revRegex))
+        throw Error("invalid Git revision '%s'", rev);
+
+    Path cacheDir = getCacheDir() + "/nix/git";
+
+    if (!pathExists(cacheDir)) {
+        runProgram("git", true, { "init", "--bare", cacheDir });
+    }
+
+    std::string localRef = hashString(htSHA256, fmt("%s-%s", uri, *ref)).to_string(Base32, false);
+
+    Path localRefFile = cacheDir + "/refs/heads/" + localRef;
+
+    bool doFetch;
+    time_t now = time(0);
+    /* If a rev was specified, we need to fetch if it's not in the
+       repo. */
+    if (rev != "") {
+        try {
+            runProgram("git", true, { "-C", cacheDir, "cat-file", "-e", rev });
+            doFetch = false;
+        } catch (ExecError & e) {
+            if (WIFEXITED(e.status)) {
+                doFetch = true;
+            } else {
+                throw;
+            }
+        }
+    } else {
+        /* If the local ref is older than ‘tarball-ttl’ seconds, do a
+           git fetch to update the local ref to the remote ref. */
+        struct stat st;
+        doFetch = stat(localRefFile.c_str(), &st) != 0 ||
+            st.st_mtime <= now - settings.tarballTtl;
+    }
+    if (doFetch)
+    {
+        Activity act(*logger, lvlTalkative, actUnknown, fmt("fetching Git repository '%s'", uri));
+
+        // FIXME: git stderr messes up our progress indicator, so
+        // we're using --quiet for now. Should process its stderr.
+        runProgram("git", true, { "-C", cacheDir, "fetch", "--quiet", "--force", "--", uri, *ref + ":" + localRef });
+
+        struct timeval times[2];
+        times[0].tv_sec = now;
+        times[0].tv_usec = 0;
+        times[1].tv_sec = now;
+        times[1].tv_usec = 0;
+
+        utimes(localRefFile.c_str(), times);
+    }
+
+    // FIXME: check whether rev is an ancestor of ref.
+    GitInfo gitInfo;
+    gitInfo.rev = rev != "" ? rev : chomp(readFile(localRefFile));
+    gitInfo.shortRev = std::string(gitInfo.rev, 0, 7);
+
+    printTalkative("using revision %s of repo '%s'", gitInfo.rev, uri);
+
+    std::string storeLinkName = hashString(htSHA512, name + std::string("\0"s) + gitInfo.rev).to_string(Base32, false);
+    Path storeLink = cacheDir + "/" + storeLinkName + ".link";
+    PathLocks storeLinkLock({storeLink}, fmt("waiting for lock on '%1%'...", storeLink)); // FIXME: broken
+
+    try {
+        auto json = nlohmann::json::parse(readFile(storeLink));
+
+        assert(json["name"] == name && json["rev"] == gitInfo.rev);
+
+        gitInfo.storePath = json["storePath"];
+
+        if (store->isValidPath(gitInfo.storePath)) {
+            gitInfo.revCount = json["revCount"];
+            return gitInfo;
+        }
+
+    } catch (SysError & e) {
+        if (e.errNo != ENOENT) throw;
+    }
+
+    // FIXME: should pipe this, or find some better way to extract a
+    // revision.
+    auto tar = runProgram("git", true, { "-C", cacheDir, "archive", gitInfo.rev });
+
+    Path tmpDir = createTempDir();
+    AutoDelete delTmpDir(tmpDir, true);
+
+    runProgram("tar", true, { "x", "-C", tmpDir }, tar);
+
+    gitInfo.storePath = store->addToStore(name, tmpDir);
+
+    gitInfo.revCount = std::stoull(runProgram("git", true, { "-C", cacheDir, "rev-list", "--count", gitInfo.rev }));
+
+    nlohmann::json json;
+    json["storePath"] = gitInfo.storePath;
+    json["uri"] = uri;
+    json["name"] = name;
+    json["rev"] = gitInfo.rev;
+    json["revCount"] = gitInfo.revCount;
+
+    writeFile(storeLink, json.dump());
+
+    return gitInfo;
+}
+
+static void prim_fetchGit(EvalState & state, const Pos & pos, Value * * args, Value & v)
+{
+    std::string url;
+    std::experimental::optional<std::string> ref;
+    std::string rev;
+    std::string name = "source";
+    PathSet context;
+
+    state.forceValue(*args[0]);
+
+    if (args[0]->type == tAttrs) {
+
+        state.forceAttrs(*args[0], pos);
+
+        for (auto & attr : *args[0]->attrs) {
+            string n(attr.name);
+            if (n == "url")
+                url = state.coerceToString(*attr.pos, *attr.value, context, false, false);
+            else if (n == "ref")
+                ref = state.forceStringNoCtx(*attr.value, *attr.pos);
+            else if (n == "rev")
+                rev = state.forceStringNoCtx(*attr.value, *attr.pos);
+            else if (n == "name")
+                name = state.forceStringNoCtx(*attr.value, *attr.pos);
+            else
+                throw EvalError("unsupported argument '%s' to 'fetchGit', at %s", attr.name, *attr.pos);
+        }
+
+        if (url.empty())
+            throw EvalError(format("'url' argument required, at %1%") % pos);
+
+    } else
+        url = state.coerceToString(pos, *args[0], context, false, false);
+
+    if (!isUri(url)) url = absPath(url);
+
+    // FIXME: git externals probably can be used to bypass the URI
+    // whitelist. Ah well.
+    state.checkURI(url);
+
+    auto gitInfo = exportGit(state.store, url, ref, rev, name);
+
+    state.mkAttrs(v, 8);
+    mkString(*state.allocAttr(v, state.sOutPath), gitInfo.storePath, PathSet({gitInfo.storePath}));
+    mkString(*state.allocAttr(v, state.symbols.create("rev")), gitInfo.rev);
+    mkString(*state.allocAttr(v, state.symbols.create("shortRev")), gitInfo.shortRev);
+    mkInt(*state.allocAttr(v, state.symbols.create("revCount")), gitInfo.revCount);
+    v.attrs->sort();
+
+    if (state.allowedPaths)
+        state.allowedPaths->insert(gitInfo.storePath);
+}
+
+static RegisterPrimOp r("fetchGit", 1, prim_fetchGit);
+
+}

src/libexpr/primops/fetchMercurial.cc

@@ -0,0 +1,209 @@
+#include "primops.hh"
+#include "eval-inline.hh"
+#include "download.hh"
+#include "store-api.hh"
+#include "pathlocks.hh"
+
+#include <sys/time.h>
+
+#include <regex>
+
+#include <nlohmann/json.hpp>
+
+using namespace std::string_literals;
+
+namespace nix {
+
+struct HgInfo
+{
+    Path storePath;
+    std::string branch;
+    std::string rev;
+    uint64_t revCount = 0;
+};
+
+std::regex commitHashRegex("^[0-9a-fA-F]{40}$");
+
+HgInfo exportMercurial(ref<Store> store, const std::string & uri,
+    std::string rev, const std::string & name)
+{
+    if (settings.pureEval && rev == "")
+        throw Error("in pure evaluation mode, 'fetchMercurial' requires a Mercurial revision");
+
+    if (rev == "" && hasPrefix(uri, "/") && pathExists(uri + "/.hg")) {
+
+        bool clean = runProgram("hg", true, { "status", "-R", uri, "--modified", "--added", "--removed" }) == "";
+
+        if (!clean) {
+
+            /* This is an unclean working tree. So copy all tracked
+               files. */
+
+            printTalkative("copying unclean Mercurial working tree '%s'", uri);
+
+            HgInfo hgInfo;
+            hgInfo.rev = "0000000000000000000000000000000000000000";
+            hgInfo.branch = chomp(runProgram("hg", true, { "branch", "-R", uri }));
+
+            auto files = tokenizeString<std::set<std::string>>(
+                runProgram("hg", true, { "status", "-R", uri, "--clean", "--modified", "--added", "--no-status", "--print0" }), "\0"s);
+
+            PathFilter filter = [&](const Path & p) -> bool {
+                assert(hasPrefix(p, uri));
+                std::string file(p, uri.size() + 1);
+
+                auto st = lstat(p);
+
+                if (S_ISDIR(st.st_mode)) {
+                    auto prefix = file + "/";
+                    auto i = files.lower_bound(prefix);
+                    return i != files.end() && hasPrefix(*i, prefix);
+                }
+
+                return files.count(file);
+            };
+
+            hgInfo.storePath = store->addToStore("source", uri, true, htSHA256, filter);
+
+            return hgInfo;
+        }
+    }
+
+    if (rev == "") rev = "default";
+
+    Path cacheDir = fmt("%s/nix/hg/%s", getCacheDir(), hashString(htSHA256, uri).to_string(Base32, false));
+
+    Path stampFile = fmt("%s/.hg/%s.stamp", cacheDir, hashString(htSHA512, rev).to_string(Base32, false));
+
+    /* If we haven't pulled this repo less than ‘tarball-ttl’ seconds,
+       do so now. */
+    time_t now = time(0);
+    struct stat st;
+    if (stat(stampFile.c_str(), &st) != 0 ||
+        st.st_mtime <= now - settings.tarballTtl)
+    {
+        /* Except that if this is a commit hash that we already have,
+           we don't have to pull again. */
+        if (!(std::regex_match(rev, commitHashRegex)
+                && pathExists(cacheDir)
+                && runProgram(
+                    RunOptions("hg", { "log", "-R", cacheDir, "-r", rev, "--template", "1" })
+                    .killStderr(true)).second == "1"))
+        {
+            Activity act(*logger, lvlTalkative, actUnknown, fmt("fetching Mercurial repository '%s'", uri));
+
+            if (pathExists(cacheDir)) {
+                runProgram("hg", true, { "pull", "-R", cacheDir, "--", uri });
+            } else {
+                createDirs(dirOf(cacheDir));
+                runProgram("hg", true, { "clone", "--noupdate", "--", uri, cacheDir });
+            }
+        }
+
+        writeFile(stampFile, "");
+    }
+
+    auto tokens = tokenizeString<std::vector<std::string>>(
+        runProgram("hg", true, { "log", "-R", cacheDir, "-r", rev, "--template", "{node} {rev} {branch}" }));
+    assert(tokens.size() == 3);
+
+    HgInfo hgInfo;
+    hgInfo.rev = tokens[0];
+    hgInfo.revCount = std::stoull(tokens[1]);
+    hgInfo.branch = tokens[2];
+
+    std::string storeLinkName = hashString(htSHA512, name + std::string("\0"s) + hgInfo.rev).to_string(Base32, false);
+    Path storeLink = fmt("%s/.hg/%s.link", cacheDir, storeLinkName);
+
+    try {
+        auto json = nlohmann::json::parse(readFile(storeLink));
+
+        assert(json["name"] == name && json["rev"] == hgInfo.rev);
+
+        hgInfo.storePath = json["storePath"];
+
+        if (store->isValidPath(hgInfo.storePath)) {
+            printTalkative("using cached Mercurial store path '%s'", hgInfo.storePath);
+            return hgInfo;
+        }
+
+    } catch (SysError & e) {
+        if (e.errNo != ENOENT) throw;
+    }
+
+    Path tmpDir = createTempDir();
+    AutoDelete delTmpDir(tmpDir, true);
+
+    runProgram("hg", true, { "archive", "-R", cacheDir, "-r", rev, tmpDir });
+
+    deletePath(tmpDir + "/.hg_archival.txt");
+
+    hgInfo.storePath = store->addToStore(name, tmpDir);
+
+    nlohmann::json json;
+    json["storePath"] = hgInfo.storePath;
+    json["uri"] = uri;
+    json["name"] = name;
+    json["branch"] = hgInfo.branch;
+    json["rev"] = hgInfo.rev;
+    json["revCount"] = hgInfo.revCount;
+
+    writeFile(storeLink, json.dump());
+
+    return hgInfo;
+}
+
+static void prim_fetchMercurial(EvalState & state, const Pos & pos, Value * * args, Value & v)
+{
+    std::string url;
+    std::string rev;
+    std::string name = "source";
+    PathSet context;
+
+    state.forceValue(*args[0]);
+
+    if (args[0]->type == tAttrs) {
+
+        state.forceAttrs(*args[0], pos);
+
+        for (auto & attr : *args[0]->attrs) {
+            string n(attr.name);
+            if (n == "url")
+                url = state.coerceToString(*attr.pos, *attr.value, context, false, false);
+            else if (n == "rev")
+                rev = state.forceStringNoCtx(*attr.value, *attr.pos);
+            else if (n == "name")
+                name = state.forceStringNoCtx(*attr.value, *attr.pos);
+            else
+                throw EvalError("unsupported argument '%s' to 'fetchMercurial', at %s", attr.name, *attr.pos);
+        }
+
+        if (url.empty())
+            throw EvalError(format("'url' argument required, at %1%") % pos);
+
+    } else
+        url = state.coerceToString(pos, *args[0], context, false, false);
+
+    if (!isUri(url)) url = absPath(url);
+
+    // FIXME: git externals probably can be used to bypass the URI
+    // whitelist. Ah well.
+    state.checkURI(url);
+
+    auto hgInfo = exportMercurial(state.store, url, rev, name);
+
+    state.mkAttrs(v, 8);
+    mkString(*state.allocAttr(v, state.sOutPath), hgInfo.storePath, PathSet({hgInfo.storePath}));
+    mkString(*state.allocAttr(v, state.symbols.create("branch")), hgInfo.branch);
+    mkString(*state.allocAttr(v, state.symbols.create("rev")), hgInfo.rev);
+    mkString(*state.allocAttr(v, state.symbols.create("shortRev")), std::string(hgInfo.rev, 0, 12));
+    mkInt(*state.allocAttr(v, state.symbols.create("revCount")), hgInfo.revCount);
+    v.attrs->sort();
+
+    if (state.allowedPaths)
+        state.allowedPaths->insert(hgInfo.storePath);
+}
+
+static RegisterPrimOp r("fetchMercurial", 1, prim_fetchMercurial);
+
+}

src/libexpr/primops/fetchgit.cc

@@ -1,84 +0,0 @@
-#include "primops.hh"
-#include "eval-inline.hh"
-#include "download.hh"
-#include "store-api.hh"
-
-namespace nix {
-
-Path exportGit(ref<Store> store, const std::string & uri, const std::string & rev)
-{
-    if (!isUri(uri))
-        throw EvalError(format("‘%s’ is not a valid URI") % uri);
-
-    Path cacheDir = getCacheDir() + "/nix/git";
-
-    if (!pathExists(cacheDir)) {
-        createDirs(cacheDir);
-        runProgram("git", true, { "init", "--bare", cacheDir });
-    }
-
-    //Activity act(*logger, lvlInfo, format("fetching Git repository ‘%s’") % uri);
-
-    std::string localRef = "pid-" + std::to_string(getpid());
-    Path localRefFile = cacheDir + "/refs/heads/" + localRef;
-
-    runProgram("git", true, { "-C", cacheDir, "fetch", uri, rev + ":" + localRef });
-
-    std::string commitHash = chomp(readFile(localRefFile));
-
-    unlink(localRefFile.c_str());
-
-    debug(format("got revision ‘%s’") % commitHash);
-
-    // FIXME: should pipe this, or find some better way to extract a
-    // revision.
-    auto tar = runProgram("git", true, { "-C", cacheDir, "archive", commitHash });
-
-    Path tmpDir = createTempDir();
-    AutoDelete delTmpDir(tmpDir, true);
-
-    runProgram("tar", true, { "x", "-C", tmpDir }, tar);
-
-    return store->addToStore("git-export", tmpDir);
-}
-
-static void prim_fetchgit(EvalState & state, const Pos & pos, Value * * args, Value & v)
-{
-    // FIXME: cut&paste from fetch().
-    if (state.restricted) throw Error("‘fetchgit’ is not allowed in restricted mode");
-
-    std::string url;
-    std::string rev = "master";
-
-    state.forceValue(*args[0]);
-
-    if (args[0]->type == tAttrs) {
-
-        state.forceAttrs(*args[0], pos);
-
-        for (auto & attr : *args[0]->attrs) {
-            string name(attr.name);
-            if (name == "url") {
-                PathSet context;
-                url = state.coerceToString(*attr.pos, *attr.value, context, false, false);
-                if (hasPrefix(url, "/")) url = "file://" + url;
-            } else if (name == "rev")
-                rev = state.forceStringNoCtx(*attr.value, *attr.pos);
-            else
-                throw EvalError("unsupported argument ‘%s’ to ‘fetchgit’, at %s", attr.name, *attr.pos);
-        }
-
-        if (url.empty())
-            throw EvalError(format("‘url’ argument required, at %1%") % pos);
-
-    } else
-        url = state.forceStringNoCtx(*args[0], pos);
-
-    Path storePath = exportGit(state.store, url, rev);
-
-    mkString(v, storePath, PathSet({storePath}));
-}
-
-static RegisterPrimOp r("__fetchgit", 1, prim_fetchgit);
-
-}