msys2-runtime: adjust CWD magic to accommodate for the latest Windows previews
This is a companion of https://github.com/msys2/msys2-runtime/pull/264. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
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@ -0,0 +1,67 @@
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From 7878787624144cd3b9cbd8a41b25d7d266b7173c Mon Sep 17 00:00:00 2001
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From: Johannes Schindelin <johannes.schindelin@gmx.de>
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Date: Mon, 22 May 2023 13:36:27 +0200
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Subject: [PATCH 54/N] Cygwin: Adjust CWD magic to accommodate for the latest
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Windows previews
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Reportedly a very recent internal build of Windows 11 once again changed
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the current working directory logic a bit, and Cygwin's "magic" (or:
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"technologically sufficiently advanced") code needs to be adjusted
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accordingly.
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In particular, the following assembly code can be seen:
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ntdll!RtlpReferenceCurrentDirectory
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598 00000001`800c6925 488d0db4cd0f00 lea rcx,[ntdll!FastPebLock (00000001`801c36e0)]
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583 00000001`800c692c 4c897810 mov qword ptr [rax+10h],r15
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588 00000001`800c6930 0f1140c8 movups xmmword ptr [rax-38h],xmm0
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598 00000001`800c6934 e82774f4ff call ntdll!RtlEnterCriticalSection
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The change necessarily looks a bit different than 4840a56325 (Cygwin:
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Adjust CWD magic to accommodate for the latest Windows previews,
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2023-05-22): The needle `\x48\x8d\x0d` is already present, as the first
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version of the hack after Windows 8.1 was released. In that code,
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though, the `call` to `RtlEnterCriticalSection` followed the `lea`
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instruction immediately, but now there are two more instructions
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separating them.
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Note: In the long run, we may very well want to follow the insightful
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suggestion by a helpful Windows kernel engineer who pointed out that it
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may be less fragile to implement kind of a disassembler that has a
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better chance to adapt to the ever-changing code of
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`ntdll!RtlpReferenceCurrentDirectory` by skipping uninteresting
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instructions such as `mov %rsp,%rax`, `mov %rbx,0x20(%rax)`, `push %rsi`
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`sub $0x70,%rsp`, etc, and focuses on finding the `lea`, `call
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ntdll!RtlEnterCriticalSection` and `mov ..., rbx` instructions, much
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like it was prototyped out for ARM64 at
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https://gist.github.com/jeremyd2019/aa167df0a0ae422fa6ebaea5b60c80c9
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Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
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---
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winsup/cygwin/path.cc | 12 ++++++++++++
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1 file changed, 12 insertions(+)
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diff --git a/winsup/cygwin/path.cc b/winsup/cygwin/path.cc
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index 33eb644..2ca929b 100644
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--- a/winsup/cygwin/path.cc
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+++ b/winsup/cygwin/path.cc
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@@ -4883,6 +4883,18 @@ find_fast_cwd_pointer ()
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%rcx for the subsequent RtlEnterCriticalSection call. */
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lock = (const uint8_t *) memmem ((const char *) use_cwd, 80,
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"\x48\x8d\x0d", 3);
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+ if (lock)
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+ {
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+ /* A recent Windows 11 Preview calls `lea rel(rip),%rcx' then
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+ a `mov` and a `movups` instruction, and only then
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+ `callq RtlEnterCriticalSection'.
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+ */
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+ if (memmem (lock + 7, 8, "\x4c\x89\x78\x10\x0f\x11\x40\xc8", 8))
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+ {
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+ call_rtl_offset = 15;
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+ }
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+ }
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+
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if (!lock)
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{
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/* Windows 8.1 Preview calls `lea rel(rip),%r12' then some unrelated
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@ -4,7 +4,7 @@
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pkgbase=msys2-runtime
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pkgname=('msys2-runtime' 'msys2-runtime-devel')
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pkgver=3.5.7
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pkgrel=3
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pkgrel=4
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pkgdesc="Cygwin POSIX emulation engine"
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arch=('x86_64')
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url="https://www.cygwin.com/"
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@ -81,7 +81,8 @@ source=('msys2-runtime'::git://sourceware.org/git/newlib-cygwin.git#tag=cygwin-$
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0050-fixup-Instead-of-creating-Cygwin-symlinks-use-deep-c.patch
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0051-fixup-Instead-of-creating-Cygwin-symlinks-use-deep-c.patch
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0052-amend-Instead-of-creating-Cygwin-symlinks-use-deep-c.patch
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0053-Cygwin-console-Redesign-mode-set-strategy-on-close.patch)
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0053-Cygwin-console-Redesign-mode-set-strategy-on-close.patch
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0054-Cygwin-Adjust-CWD-magic-to-accommodate-for-the-lates.patch)
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sha256sums=('e78e129eed8e2dd4a2600fe6df8cb6f3beb9dca786574823ed55951adecb7064'
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'87d86c95008274731cf560d929ae5fb319d962591303b2690e11bfd60f4818e7'
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'c6d091cb51440638eb9fc59b35ba40f2b63e9e32a31a56c51a2aaec2445aa88e'
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@ -135,7 +136,8 @@ sha256sums=('e78e129eed8e2dd4a2600fe6df8cb6f3beb9dca786574823ed55951adecb7064'
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'e24911a237886d043959ccf64a4f862e91b0d9e322f200d255355040aae3ea16'
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'54e01260a3b481f2e178f2d603442d206b497b554a530c85d365febb11b12488'
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'086916ec5e3f038d6b815f268880bdda39b574efaa1c9a53fdc08ce46a57ba20'
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'9ffbb094aa5d9616cae3fc8df6aaf4db64cd5dbe80144147b6aa68ba6e99b25c')
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'9ffbb094aa5d9616cae3fc8df6aaf4db64cd5dbe80144147b6aa68ba6e99b25c'
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'0a878a8b9a4ec43316bebcf67832b91104c8598b3a7eb7d6c9b9fb33da8114e3')
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# Helper macros to help make tasks easier #
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apply_patch_with_msg() {
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@ -225,7 +227,8 @@ prepare() {
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0050-fixup-Instead-of-creating-Cygwin-symlinks-use-deep-c.patch \
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0051-fixup-Instead-of-creating-Cygwin-symlinks-use-deep-c.patch \
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0052-amend-Instead-of-creating-Cygwin-symlinks-use-deep-c.patch \
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0053-Cygwin-console-Redesign-mode-set-strategy-on-close.patch
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0053-Cygwin-console-Redesign-mode-set-strategy-on-close.patch \
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0054-Cygwin-Adjust-CWD-magic-to-accommodate-for-the-lates.patch
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}
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build() {
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