Befator-Inc-Firmen-Netzwerk/nix
3
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Merge pull request #15333 from NixOS/canon-path-from-filename

Browse Source 
Introduce `CanonPath::fromFilename`
This commit is contained in:
John Ericson
2026-02-25 15:59:09 +00:00
committed by GitHub
parent 16f10c1321 7275556d61
commit a2d1346852
5 changed files with 40 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
src/libstore/unix/build/derivation-builder.cc
View File

@@ -1270,13 +1270,10 @@ void DerivationBuilderImpl::chownToBuilder(int fd, const std::filesystem::path &
void DerivationBuilderImpl::writeBuilderFile(const std::string & name, std::string_view contents)
{
auto relPath = CanonPath(name);
/* Path must be the same after normalisation. This is an additional sanity check in addition to
existing parsing checks for non-structured attrs exportReferencesGraph. In practice we only expect
a single path component without any `..`, `.` components. */
if (relPath.rel() != name || std::ranges::distance(relPath) != 1)
throw Error("invalid file name for a builder file: '%s'", name);
auto relPath = CanonPath::fromFilename(name);
AutoCloseFD fd = openFileEnsureBeneathNoSymlinks(
tmpDirFd.get(), relPath, O_WRONLY | O_TRUNC | O_CREAT | O_CLOEXEC | O_EXCL | O_NOFOLLOW, 0666);
auto path = tmpDir / relPath.rel(); /* This is used only for error messages. */

13
src/libutil-tests/canon-path.cc
View File

@@ -51,6 +51,19 @@ TEST(CanonPath, nullBytes)
ASSERT_THROW(CanonPath(s, CanonPath::root), BadCanonPath);
}
TEST(CanonPath, fromFilename)
{
ASSERT_THROW(CanonPath::fromFilename("."), BadCanonPath);
ASSERT_THROW(CanonPath::fromFilename(".."), BadCanonPath);
ASSERT_THROW(CanonPath::fromFilename(""), BadCanonPath);
ASSERT_THROW(CanonPath::fromFilename("/.."), BadCanonPath);
ASSERT_THROW(CanonPath::fromFilename("/."), BadCanonPath);
ASSERT_THROW(CanonPath::fromFilename("/abc"), BadCanonPath);
ASSERT_THROW(CanonPath::fromFilename("abc/d"), BadCanonPath);
ASSERT_THROW(CanonPath::fromFilename("/abc/d"), BadCanonPath);
ASSERT_EQ(CanonPath::fromFilename("abc").rel(), "abc");
}
TEST(CanonPath, from_existing)
{
CanonPath p0("foo//bar/");

10
src/libutil/canon-path.cc
View File

@@ -23,6 +23,16 @@ static void ensureNoNullBytes(std::string_view s)
}
}
CanonPath CanonPath::fromFilename(std::string_view segment)
{
auto res = CanonPath(segment);
/* Use existing canonicalisation logic for CanonPath to check that the segment
is already a valid filename. */
if (segment != res.rel() || std::ranges::distance(res) != 1)
throw BadCanonPath("invalid filename '%s'", segment);
return res;
}
CanonPath::CanonPath(std::string_view raw)
: path(absPathPure(concatStrings("/", raw)))
{

8
src/libutil/include/nix/util/canon-path.hh
View File

@@ -62,7 +62,7 @@ public:
struct unchecked_t
{};
CanonPath(unchecked_t _, std::string path)
constexpr CanonPath(unchecked_t _, std::string path)
: path(std::move(path))
{
}
@@ -74,6 +74,12 @@ public:
static const CanonPath root;
/**
* Construct a CanonPath from a single path segment. The segment
* must not contain any slashes and must not be `.` or `..`.
*/
static CanonPath fromFilename(std::string_view segment);
/**
* If `raw` starts with a slash, return
* `CanonPath(raw)`. Otherwise return a `CanonPath` representing

18
src/libutil/unix/file-system.cc
View File

@@ -146,11 +146,10 @@ static void _deletePath(
}
#endif
std::string name(path.filename());
assert(name != "." && name != ".." && !name.empty());
auto name = CanonPath::fromFilename(path.filename().native());
PosixStat st;
if (fstatat(parentfd, name.c_str(), &st, AT_SYMLINK_NOFOLLOW) == -1) {
if (fstatat(parentfd, name.rel_c_str(), &st, AT_SYMLINK_NOFOLLOW) == -1) {
if (errno == ENOENT)
return;
throw SysError("getting status of %1%", PathFmt(path));
@@ -185,7 +184,7 @@ static void _deletePath(
const auto PERM_MASK = S_IRUSR | S_IWUSR | S_IXUSR;
if ((st.st_mode & PERM_MASK) != PERM_MASK)
try {
unix::fchmodatTryNoFollow(parentfd, CanonPath(name), st.st_mode | PERM_MASK);
unix::fchmodatTryNoFollow(parentfd, name, st.st_mode | PERM_MASK);
} catch (SysError & e) {
e.addTrace({}, "while making directory %1% accessible for deletion", PathFmt(path));
if (e.errNo == EOPNOTSUPP)
@@ -193,7 +192,7 @@ static void _deletePath(
throw;
}
int fd = openat(parentfd, name.c_str(), O_RDONLY | O_DIRECTORY | O_NOFOLLOW);
int fd = openat(parentfd, name.rel_c_str(), O_RDONLY | O_DIRECTORY | O_NOFOLLOW);
if (fd == -1)
throw SysError("opening directory %1%", PathFmt(path));
AutoCloseDir dir(fdopendir(fd));
@@ -213,7 +212,7 @@ static void _deletePath(
}
int flags = S_ISDIR(st.st_mode) ? AT_REMOVEDIR : 0;
if (unlinkat(parentfd, name.c_str(), flags) == -1) {
if (unlinkat(parentfd, name.rel_c_str(), flags) == -1) {
if (errno == ENOENT)
return;
try {
@@ -230,13 +229,14 @@ static void _deletePath(
static void _deletePath(const std::filesystem::path & path, uint64_t & bytesFreed MOUNTEDPATHS_PARAM)
{
assert(path.is_absolute());
assert(path.parent_path() != path);
auto parentDirPath = path.parent_path();
assert(parentDirPath != path);
AutoCloseFD dirfd = toDescriptor(open(path.parent_path().string().c_str(), O_RDONLY));
AutoCloseFD dirfd = openDirectory(parentDirPath);
if (!dirfd) {
if (errno == ENOENT)
return;
throw SysError("opening directory %s", PathFmt(path.parent_path()));
throw SysError("opening directory %s", PathFmt(parentDirPath));
}
std::exception_ptr ex;