Commit Graph

1113 Commits

Author SHA1 Message Date
Johannes Schindelin
514b5ef058 Merge pull request #3165 from dscho/increase-allowed-length-of-interpreter-path
mingw: allow for longer paths in `parse_interpreter()`
2025-02-06 19:11:37 +01:00
Johannes Schindelin
a82f8fa5dc Merge pull request #2915 from dennisameling/windows-arm64-support
Windows arm64 support
2025-02-06 19:11:36 +01:00
Johannes Schindelin
70d6906ff3 Merge pull request #2351 from PhilipOakley/vcpkg-tip
Vcpkg Install: detect lack of working Git, and note possible vcpkg time outs
2025-02-06 19:11:36 +01:00
Johannes Schindelin
de4d0adbdc Merge pull request #2974 from derrickstolee/maintenance-and-headless
Include Windows-specific maintenance and headless-git
2025-02-06 19:11:36 +01:00
Jeff Hostetler
4f8ede9d29 clink.pl: move default linker options for MSVC=1 builds
Move the default `-ENTRY` and `-SUBSYSTEM` arguments for
MSVC=1 builds from `config.mak.uname` into `clink.pl`.
These args are constant for console-mode executables.

Add support to `clink.pl` for generating a Win32 GUI application
using the `-mwindows` argument (to match how GCC does it).  This
changes the `-ENTRY` and `-SUBSYSTEM` arguments accordingly.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
2025-02-06 19:11:22 +01:00
Jeff Hostetler
a2e538342b clink.pl: ignore no-stack-protector arg on MSVC=1 builds
Ignore the `-fno-stack-protector` compiler argument when building
with MSVC.  This will be used in a later commit that needs to build
a Win32 GUI app.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
2025-02-06 19:11:21 +01:00
Jeff Hostetler
369ff79d5a vcbuild: add support for compiling Windows resource files
Create a wrapper for the Windows Resource Compiler (RC.EXE)
for use by the MSVC=1 builds. This is similar to the CL.EXE
and LIB.EXE wrappers used for the MSVC=1 builds.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
2025-02-06 19:11:21 +01:00
Jeff Hostetler
bab125e377 clink.pl: fix libexpatd.lib link error when using MSVC
When building with `make MSVC=1 DEBUG=1`, link to `libexpatd.lib`
rather than `libexpat.lib`.

It appears that the `vcpkg` package for "libexpat" has changed and now
creates `libexpatd.lib` for debug mode builds.  Previously, both debug
and release builds created a ".lib" with the same basename.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
2025-02-06 19:11:21 +01:00
Johannes Schindelin
efd59cc4d5 Merge pull request #2506 from dscho/issue-2283
Allow running Git directly from `C:\Program Files\Git\mingw64\bin\git.exe`
2025-02-06 17:59:42 +01:00
Johannes Schindelin
35b304f895 Merge pull request #2504 from dscho/access-repo-via-junction
Handle `git add <file>` where <file> traverses an NTFS junction
2025-02-06 17:59:41 +01:00
Johannes Schindelin
85f3f1f60a Merge pull request #2501 from jeffhostetler/clink-debug-curl
clink.pl: fix MSVC compile script to handle libcurl-d.lib
2025-02-06 17:59:41 +01:00
Johannes Schindelin
0834dd1178 Merge pull request #2488 from bmueller84/master
mingw: fix fatal error working on mapped network drives on Windows
2025-02-06 17:59:41 +01:00
Johannes Schindelin
5e863bad2f Merge pull request #2449 from dscho/mingw-getcwd-and-symlinks
Do resolve symlinks in `getcwd()`
2025-02-06 17:59:41 +01:00
Johannes Schindelin
320cfb0759 Merge branch 'mimalloc-v2.0.9'
This topic vendors in mimalloc v2.0.9, a fast allocator that allows Git
for Windows to perform efficiently.

Switch Git for Windows to using mimalloc instead of nedmalloc
2025-02-06 17:59:40 +01:00
Johannes Schindelin
d4f263dcaf Merge branch 'dont-clean-junctions'
This topic branch teaches `git clean` to respect NTFS junctions and Unix
bind mounts: it will now stop at those boundaries.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2025-02-06 17:59:39 +01:00
Johannes Schindelin
e5f9ad2c73 mingw: allow for longer paths in parse_interpreter()
As reported in https://github.com/newren/git-filter-repo/pull/225, it
looks like 99 bytes is not really sufficient to represent e.g. the full
path to Python when installed via Windows Store (and this path is used
in the hasb bang line when installing scripts via `pip`).

Let's increase it to what is probably the maximum sensible path size:
MAX_PATH. This makes `parse_interpreter()` in line with what
`lookup_prog()` handles.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Vilius Šumskas <vilius@sumskas.eu>
2025-02-06 16:33:16 +01:00
Dennis Ameling
8aa481cf2d Add schannel to curl installation
Signed-off-by: Dennis Ameling <dennis@dennisameling.com>
2025-02-06 16:33:15 +01:00
Philip Oakley
08ba0df061 vcpkg_install: add comment regarding slow network connections
The vcpkg downloads may not succeed. Warn careful readers of the time out.

A simple retry will usually resolve the issue.

Signed-off-by: Philip Oakley <philipoakley@iee.email>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2025-02-06 16:33:15 +01:00
Philip Oakley
07946b3d2c vcpkg_install: detect lack of Git
The vcpkg_install batch file depends on the availability of a
working Git on the CMD path. This may not be present if the user
has selected the 'bash only' option during Git-for-Windows install.

Detect and tell the user about their lack of a working Git in the CMD
window.

Fixes #2348.
A separate PR https://github.com/git-for-windows/build-extra/pull/258
now highlights the recommended path setting during install.

Signed-off-by: Philip Oakley <philipoakley@iee.email>
2025-02-06 16:33:15 +01:00
Ian Bearman
691f9075ca vcbuild: add an option to install individual 'features'
In this context, a "feature" is a dependency combined with its own
dependencies.

Signed-off-by: Ian Bearman <ianb@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2025-02-06 16:33:15 +01:00
Ian Bearman
f17f4ef51f vcbuild: install ARM64 dependencies when building ARM64 binaries
Co-authored-by: Dennis Ameling <dennis@dennisameling.com>
Signed-off-by: Ian Bearman <ianb@microsoft.com>
Signed-off-by: Dennis Ameling <dennis@dennisameling.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2025-02-06 16:33:15 +01:00
Johannes Schindelin
da2a9df6bd mingw: ignore HOMEDRIVE/HOMEPATH if it points to Windows' system directory
Internally, Git expects the environment variable `HOME` to be set, and
to point to the current user's home directory.

This environment variable is not set by default on Windows, and
therefore Git tries its best to construct one if it finds `HOME` unset.

There are actually two different approaches Git tries: first, it looks
at `HOMEDRIVE`/`HOMEPATH` because this is widely used in corporate
environments with roaming profiles, and a user generally wants their
global Git settings to be in a roaming profile.

Only when `HOMEDRIVE`/`HOMEPATH` is either unset or does not point to a
valid location, Git will fall back to using `USERPROFILE` instead.

However, starting with Windows Vista, for secondary logons and services,
the environment variables `HOMEDRIVE`/`HOMEPATH` point to Windows'
system directory (usually `C:\Windows\system32`).

That is undesirable, and that location is usually write-protected anyway.

So let's verify that the `HOMEDRIVE`/`HOMEPATH` combo does not point to
Windows' system directory before using it, falling back to `USERPROFILE`
if it does.

This fixes git-for-windows#2709

Initial-Path-by: Ivan Pozdeev <vano@mail.mipt.ru>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2025-02-06 16:33:13 +01:00
Johannes Schindelin
d1e51aa137 mingw: implement a platform-specific strbuf_realpath()
There is a Win32 API function to resolve symbolic links, and we can use
that instead of resolving them manually. Even better, this function also
resolves NTFS junction points (which are somewhat similar to bind
mounts).

This fixes https://github.com/git-for-windows/git/issues/2481.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2025-02-06 16:33:13 +01:00
Jeff Hostetler
54449ed171 clink.pl: fix MSVC compile script to handle libcurl-d.lib
Update clink.pl to link with either libcurl.lib or libcurl-d.lib
depending on whether DEBUG=1 is set.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2025-02-06 16:33:13 +01:00
Bjoern Mueller
5b56c833b8 mingw: fix fatal error working on mapped network drives on Windows
In 1e64d18 (mingw: do resolve symlinks in `getcwd()`) a problem was
introduced that causes git for Windows to stop working with certain
mapped network drives (in particular, drives that are mapped to
locations with long path names). Error message was "fatal: Unable to
read current working directory: No such file or directory". Present
change fixes this issue as discussed in
https://github.com/git-for-windows/git/issues/2480

Signed-off-by: Bjoern Mueller <bjoernm@gmx.de>
2025-02-06 16:33:13 +01:00
Johannes Schindelin
02e80d925e mingw: do resolve symlinks in getcwd()
As pointed out in https://github.com/git-for-windows/git/issues/1676,
the `git rev-parse --is-inside-work-tree` command currently fails when
the current directory's path contains symbolic links.

The underlying reason for this bug is that `getcwd()` is supposed to
resolve symbolic links, but our `mingw_getcwd()` implementation did not.

We do have all the building blocks for that, though: the
`GetFinalPathByHandleW()` function will resolve symbolic links. However,
we only called that function if `GetLongPathNameW()` failed, for
historical reasons: the latter function was supported for a long time,
but the former API function was introduced only with Windows Vista, and
we used to support also Windows XP. With that support having been
dropped, we are free to call the symbolic link-resolving function right
away.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2025-02-06 16:33:13 +01:00
Johannes Schindelin
59dbe7e0b2 mingw: allow git.exe to be used instead of the "Git wrapper"
Git for Windows wants to add `git.exe` to the users' `PATH`, without
cluttering the latter with unnecessary executables such as `wish.exe`.
To that end, it invented the concept of its "Git wrapper", i.e. a tiny
executable located in `C:\Program Files\Git\cmd\git.exe` (originally a
CMD script) whose sole purpose is to set up a couple of environment
variables and then spawn the _actual_ `git.exe` (which nowadays lives in
`C:\Program Files\Git\mingw64\bin\git.exe` for 64-bit, and the obvious
equivalent for 32-bit installations).

Currently, the following environment variables are set unless already
initialized:

- `MSYSTEM`, to make sure that the MSYS2 Bash and the MSYS2 Perl
  interpreter behave as expected, and

- `PLINK_PROTOCOL`, to force PuTTY's `plink.exe` to use the SSH
  protocol instead of Telnet,

- `PATH`, to make sure that the `bin` folder in the user's home
  directory, as well as the `/mingw64/bin` and the `/usr/bin`
  directories are included. The trick here is that the `/mingw64/bin/`
  and `/usr/bin/` directories are relative to the top-level installation
  directory of Git for Windows (which the included Bash interprets as
  `/`, i.e. as the MSYS pseudo root directory).

Using the absence of `MSYSTEM` as a tell-tale, we can detect in
`git.exe` whether these environment variables have been initialized
properly. Therefore we can call `C:\Program Files\Git\mingw64\bin\git`
in-place after this change, without having to call Git through the Git
wrapper.

Obviously, above-mentioned directories must be _prepended_ to the `PATH`
variable, otherwise we risk picking up executables from unrelated Git
installations. We do that by constructing the new `PATH` value from
scratch, appending `$HOME/bin` (if `HOME` is set), then the MSYS2 system
directories, and then appending the original `PATH`.

Side note: this modification of the `PATH` variable is independent of
the modification necessary to reach the executables and scripts in
`/mingw64/libexec/git-core/`, i.e. the `GIT_EXEC_PATH`. That
modification is still performed by Git, elsewhere, long after making the
changes described above.

While we _still_ cannot simply hard-link `mingw64\bin\git.exe` to `cmd`
(because the former depends on a couple of `.dll` files that are only in
`mingw64\bin`, i.e. calling `...\cmd\git.exe` would fail to load due to
missing dependencies), at least we can now avoid that extra process of
running the Git wrapper (which then has to wait for the spawned
`git.exe` to finish) by calling `...\mingw64\bin\git.exe` directly, via
its absolute path.

Testing this is in Git's test suite tricky: we set up a "new" MSYS
pseudo-root and copy the `git.exe` file into the appropriate location,
then verify that `MSYSTEM` is set properly, and also that the `PATH` is
modified so that scripts can be found in `$HOME/bin`, `/mingw64/bin/`
and `/usr/bin/`.

This addresses https://github.com/git-for-windows/git/issues/2283

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2025-02-06 16:33:13 +01:00
Johannes Schindelin
dd5817d49f mingw: ensure valid CTYPE
A change between versions 2.4.1 and 2.6.0 of the MSYS2 runtime modified
how Cygwin's runtime (and hence Git for Windows' MSYS2 runtime
derivative) handles locales: d16a56306d (Consolidate wctomb/mbtowc calls
for POSIX-1.2008, 2016-07-20).

An unintended side-effect is that "cold-calling" into the POSIX
emulation will start with a locale based on the current code page,
something that Git for Windows is very ill-prepared for, as it expects
to be able to pass a command-line containing non-ASCII characters to the
shell without having those characters munged.

One symptom of this behavior: when `git clone` or `git fetch` shell out
to call `git-upload-pack` with a path that contains non-ASCII
characters, the shell tried to interpret the entire command-line
(including command-line parameters) as executable path, which obviously
must fail.

This fixes https://github.com/git-for-windows/git/issues/1036

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2025-02-06 16:33:13 +01:00
Johannes Schindelin
b86e095423 clean: remove mount points when possible
Windows' equivalent to "bind mounts", NTFS junction points, can be
unlinked without affecting the mount target. This is clearly what users
expect to happen when they call `git clean -dfx` in a worktree that
contains NTFS junction points: the junction should be removed, and the
target directory of said junction should be left alone (unless it is
inside the worktree).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2025-02-06 16:33:12 +01:00
Jeff Hostetler
7402d6534c mimalloc: use "weak" random seed when statically linked
Always use the internal "use_weak" random seed when initializing
the "mimalloc" heap when statically linked on Windows.

The imported "mimalloc" routines support several random sources
to seed the heap data structures, including BCrypt.dll and
RtlGenRandom.  Crashes have been reported when using BCrypt.dll
if it initialized during an `atexit()` handler function.  Granted,
such DLL initialization should not happen in an atexit handler,
but yet the crashes remain.

It should be noted that on Windows when statically linked, the
mimalloc startup code (called by the GCC CRT to initialize static
data prior to calling `main()`) always uses the internal "weak"
random seed.  "mimalloc" does not try to load an alternate
random source until after the OS initialization has completed.

Heap data is stored in `__declspec(thread)` TLS data and in theory
each Git thread will have its own heap data.  However, testing
shows that the "mimalloc" library doesn't actually call
`os_random_buf()` (to load a new random source) when creating these
new per-thread heap structures.

However, if an atexit handler is forced to run on a non-main
thread, the "mimalloc" library *WILL* try to create a new heap
and seed it with `os_random_buf()`.  (The reason for this is still
a mystery to this author.)  The `os_random_buf()` call can cause
the (previously uninitialized BCrypt.dll library) to be dynamically
loaded and a call made into it.  Crashes have been reported in
v2.40.1.vfs.0.0 while in this call.

As a workaround, the fix here forces the use of the internal
"use_weak" random code for the subsequent `os_random_buf()` calls.
Since we have been using that random generator for the majority
of the program, it seems safe to use it for the final few mallocs
in the atexit handler (of which there really shouldn't be that many.

Signed-off-by: Jeff Hostetler <jeffhostetler@github.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2025-02-06 16:33:12 +01:00
Johannes Schindelin
99ffa429f4 clean: do not traverse mount points
It seems to be not exactly rare on Windows to install NTFS junction
points (the equivalent of "bind mounts" on Linux/Unix) in worktrees,
e.g. to map some development tools into a subdirectory.

In such a scenario, it is pretty horrible if `git clean -dfx` traverses
into the mapped directory and starts to "clean up".

Let's just not do that. Let's make sure before we traverse into a
directory that it is not a mount point (or junction).

This addresses https://github.com/git-for-windows/git/issues/607

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2025-02-06 16:33:12 +01:00
Johannes Schindelin
3d296b091f mimalloc: adjust for building inside Git
We want to compile mimalloc's source code as part of Git, rather than
requiring the code to be built as an external library: mimalloc uses a
CMake-based build, which is not necessarily easy to integrate into the
flavors of Git for Windows (which will be the main benefitting port).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2025-02-06 16:33:12 +01:00
Johannes Schindelin
bf284f19be Import the source code of mimalloc v2.1.2
This commit imports mimalloc's source code as per v2.1.2, fetched from
the tag at https://github.com/microsoft/mimalloc.

The .c files are from the src/ subdirectory, and the .h files from the
include/ and include/mimalloc/ subdirectories. We will subsequently
modify the source code to accommodate building within Git's context.

Since we plan on using the `mi_*()` family of functions, we skip the
C++-specific source code, some POSIX compliant functions to interact
with mimalloc, and the code that wants to support auto-magic overriding
of the `malloc()` function (mimalloc-new-delete.h, alloc-posix.c,
mimalloc-override.h, alloc-override.c, alloc-override-osx.c,
alloc-override-win.c and static.c).

To appease the `check-whitespace` job of Git's Continuous Integration,
this commit was washed one time via `git rebase --whitespace=fix`.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2025-02-06 16:33:12 +01:00
Johannes Schindelin
5c6c3a3871 win32/pthread: avoid name clashes with winpthread
The mingw-w64 GCC seems to link implicitly to libwinpthread, which does
implement a pthread emulation (that is more complete than Git's). Let's
keep preferring Git's.

To avoid linker errors where it thinks that the `pthread_self` and the
`pthread_create` symbols are defined twice, let's give our version a
`win32_` prefix, just like we already do for `pthread_join()`.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2025-02-06 16:33:12 +01:00
Johannes Schindelin
5e12a91106 mingw: allow absolute paths without drive prefix
When specifying an absolute path without a drive prefix, we convert that
path internally. Let's make sure that we handle that case properly, too
;-)

This fixes the command

	git clone https://github.com/git-for-windows/git \G4W

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2025-02-06 16:33:11 +01:00
Junio C Hamano
6b442e6cf2 bswap.h: squelch potential sparse -Wcast-truncate warnings
In put_be32(), we right-shift a uint32_t value various amounts and then
assign the low 8-bits to individual "unsigned char" bytes, throwing away
the high bits. For shifts smaller than 24 bits, those thrown away bits
will be arbitrary bits from the original uint32_t.

This works exactly as we want, but if you feed a constant, then sparse
complains. For example if we write this (which we plan to do in a future
patch):

  put_be32(hdr, PACK_SIGNATURE);

then "make sparse" produces:

  compat/bswap.h:175:22: error: cast truncates bits from constant value (5041 becomes 41)
  compat/bswap.h:176:22: error: cast truncates bits from constant value (504143 becomes 43)
  compat/bswap.h:177:22: error: cast truncates bits from constant value (5041434b becomes 4b)

And the same issue exists in the other put_be*() functions, when used
with a constant.

We can silence this warning by explicitly masking off the truncated
bits. The compiler is smart enough to know the result is the same, and
the asm generated by gcc (with both -O0 and -O2) is identical.

Curiously this line already exists:

	put_be32(&hdr_version, INDEX_EXTENSION_VERSION2);

in the fsmonitor.c file, but it does not get flagged because the CPP
macro expands to a small integer (2).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
2025-02-06 16:33:07 +01:00
Junio C Hamano
c4cc685a62 Merge branch 'js/mingw-rename-fix'
Update the way rename() emulation on Windows handle directories to
correct an earlier attempt to do the same.

* js/mingw-rename-fix:
  mingw_rename: do support directory renames
2024-12-23 09:32:16 -08:00
Johannes Schindelin
b30404dfc0 mingw_rename: do support directory renames
In 391bceae43 (compat/mingw: support POSIX semantics for atomic
renames, 2024-10-27), we taught the `mingw_rename()` function to respect
POSIX semantics, but we did so only as a fallback after `_wrename()`
fails.

This hid a bug in the implementation that was not caught by Git's test
suite: The `CreateFileW()` function _can_ open handles to directories,
but not when asked to use the `FILE_ATTRIBUTE_NORMAL` flag, as that flag
only is allowed for files.

Let's fix this by using the common `FILE_FLAG_BACKUP_SEMANTICS` flag
that can be used for opening handles to directories, too.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-17 12:06:59 -08:00
Patrick Steinhardt
80c9e70ebe global: trivial conversions to fix -Wsign-compare warnings
We have a bunch of loops which iterate up to an unsigned boundary using
a signed index, which generates warnigs because we compare a signed and
unsigned value in the loop condition. Address these sites for trivial
cases and enable `-Wsign-compare` warnings for these code units.

This patch only adapts those code units where we can drop the
`DISABLE_SIGN_COMPARE_WARNINGS` macro in the same step.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-06 20:20:04 +09:00
Patrick Steinhardt
41f43b8243 global: mark code units that generate warnings with -Wsign-compare
Mark code units that generate warnings with `-Wsign-compare`. This
allows for a structured approach to get rid of all such warnings over
time in a way that can be easily measured.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-06 20:20:02 +09:00
Patrick Steinhardt
709fdce089 compat/win32: fix -Wsign-compare warning in "wWinMain()"
GCC generates a warning in "headless.c" because we compare `slash` with
`size`, where the former is an `int` and the latter is a `size_t`. Fix
the warning by storing `slash` as a `size_t`, as well.

This commit is being singled out because the file does not include the
"git-compat-util.h" header, and consequently, we cannot easily mark it
with the `DISABLE_SIGN_COMPARE_WARNING` macro.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-06 20:20:01 +09:00
Patrick Steinhardt
6e1d0ce470 compat/regex: explicitly ignore "-Wsign-compare" warnings
Explicitly ignore "-Wsign-compare" warnings in our bundled copy of the
regcomp implementation. We don't use the macro introduced in the
preceding commit because this code does not include "git-compat-util.h"
in the first place.

Note that we already directly use "#pragma GCC diagnostic ignored" in
"regcomp.c", so it shouldn't be an issue to use it directly in the new
spot, either.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-06 20:20:01 +09:00
Junio C Hamano
183ea3eabf Merge branch 'ps/mingw-rename'
The MinGW compatibility layer has been taught to support POSIX
semantics for atomic renames when other process(es) have a file
opened at the destination path.

* ps/mingw-rename:
  compat/mingw: support POSIX semantics for atomic renames
  compat/mingw: allow deletion of most opened files
  compat/mingw: share file handles created via `CreateFileW()`
2024-11-13 08:35:34 +09:00
Patrick Steinhardt
391bceae43 compat/mingw: support POSIX semantics for atomic renames
By default, Windows restricts access to files when those files have been
opened by another process. As explained in the preceding commits, these
restrictions can be loosened such that reads, writes and/or deletes of
files with open handles _are_ allowed.

While we set up those sharing flags in most relevant code paths now, we
still don't properly handle POSIX-style atomic renames in case the
target path is open. This is failure demonstrated by t0610, where one of
our tests spawns concurrent writes in a reftable-enabled repository and
expects all of them to succeed. This test fails most of the time because
the process that has acquired the "tables.list" lock is unable to rename
it into place while other processes are busy reading that file.

Windows 10 has introduced the `FILE_RENAME_FLAG_POSIX_SEMANTICS` flag
that allows us to fix this usecase [1]. When set, it is possible to
rename a file over a preexisting file even when the target file still
has handles open. Those handles must have been opened with the
`FILE_SHARE_DELETE` flag, which we have ensured in the preceding
commits.

Careful readers might have noticed that [1] does not mention the above
flag, but instead mentions `FILE_RENAME_POSIX_SEMANTICS`. This flag is
not for use with `SetFileInformationByHandle()` though, which is what we
use. And while the `FILE_RENAME_FLAG_POSIX_SEMANTICS` flag exists, it is
not documented on [2] or anywhere else as far as I can tell.

Unfortunately, we still support Windows systems older than Windows 10
that do not yet have this new flag. Our `_WIN32_WINNT` SDK version still
targets 0x0600, which is Windows Vista and later. And even though that
Windows version is out-of-support, bumping the SDK version all the way
to 0x0A00, which is Windows 10 and later, is not an option as it would
make it impossible to compile on Windows 8.1, which is still supported.
Instead, we have to manually declare the relevant infrastructure to make
this feature available and have fallback logic in place in case we run
on a Windows version that does not yet have this flag.

On another note: `mingw_rename()` has a retry loop that is used in case
deleting a file failed because it's still open in another process. One
might be pressed to not use this loop anymore when we can use POSIX
semantics. But unfortunately, we have to keep it around due to our
dependence on the `FILE_SHARE_DELETE` flag. While we know to set that
sharing flag now, other applications may not do so and may thus still
cause sharing violations when we try to rename a file.

This fixes concurrent writes in the reftable backend as demonstrated in
t0610, but may also end up fixing other usecases where Git wants to
perform renames.

[1]: https://learn.microsoft.com/en-us/windows-hardware/drivers/ddi/ntifs/ns-ntifs-_file_rename_information
[2]: https://learn.microsoft.com/en-us/windows/win32/api/winbase/ns-winbase-file_rename_info

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Reviewed-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-11-06 00:15:25 -08:00
Patrick Steinhardt
a270cb1540 compat/mingw: allow deletion of most opened files
On Windows, we emulate open(3p) via `mingw_open()`. This function
implements handling of some platform-specific quirks that are required
to make it behave as closely as possible like open(3p) would, but for
most cases we just call the Windows-specific `_wopen()` function.

This function has a major downside though: it does not allow us to
specify the sharing mode. While there is `_wsopen()` that allows us to
pass sharing flags, those sharing flags are not the same `FILE_SHARE_*`
flags as `CreateFileW()` accepts. Instead, `_wsopen()` only allows
concurrent read- and write-access, but does not allow for concurrent
deletions. Unfortunately though, we have to allow concurrent deletions
if we want to have POSIX-style atomic renames on top of an existing file
that has open file handles.

Implement a new function that emulates open(3p) for existing files via
`CreateFileW()` such that we can set the required sharing flags.

While we have the same issue when calling open(3p) with `O_CREAT`,
implementing that mode would be more complex due to the required
permission handling. Furthermore, atomic updates via renames typically
write to exclusive lockfile and then perform the rename, and thus we
don't have to handle the case where the locked path has been created
with `O_CREATE`. So while it would be nice to have proper POSIX
semantics in all paths, we instead aim for a minimum viable fix here.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
2024-10-27 19:51:35 -04:00
Patrick Steinhardt
b0b65ec593 compat/mingw: share file handles created via CreateFileW()
Unless told otherwise, Windows will keep other processes from reading,
writing and deleting files when one has an open handle that was created
via `CreateFileW()`. This behaviour can be altered via `FILE_SHARE_*`
flags:

  - `FILE_SHARE_READ` allows a concurrent process to open the file for
    reading.

  - `FILE_SHARE_WRITE` allows a concurrent process to open the file for
    writing.

  - `FILE_SHARE_DELETE` allows a concurrent process to delete the file
    or to replace it via an atomic rename.

This sharing mechanism is quite important in the context of Git, as we
assume POSIX semantics all over the place. But there are two callsites
where we don't pass all three of these flags:

  - We don't set `FILE_SHARE_DELETE` when creating a file for appending
    via `mingw_open_append()`. This makes it impossible to delete the
    file from another process or to replace it via an atomic rename. The
    function was introduced via d641097589 (mingw: enable atomic
    O_APPEND, 2018-08-13) and has been using `FILE_SHARE_READ |
    FILE_SHARE_WRITE` since the inception. There aren't any indicators
    that the omission of `FILE_SHARE_DELETE` was intentional.

  - We don't set any sharing flags in `mingw_utime()`, which changes the
    access and modification of a file. This makes it impossible to
    perform any kind of operation on this file at all from another
    process. While we only open the file for a short amount of time to
    update its timestamps, this still opens us up for a race condition
    with another process.

    `mingw_utime()` was originally implemented via `_wopen()`, which
    doesn't give you full control over the sharing mode. Instead, it
    calls `_wsopen()` with `_SH_DENYNO`, which ultimately translates to
    `FILE_SHARE_READ | FILE_SHARE_WRITE`. It was then refactored via
    090a3085bc (t/helper/test-chmtime: update mingw to support chmtime
    on directories, 2022-03-02) to use `CreateFileW()`, but we stopped
    setting any sharing flags at all, which seems like an unintentional
    side effect. By restoring `FILE_SHARE_READ | FILE_SHARE_WRITE` we
    thus fix this and get back the old behaviour of `_wopen()`.

    The fact that we didn't set the equivalent of `FILE_SHARE_DELETE`
    can be explained, as well: neither `_wopen()` nor `_wsopen()` allow
    you to do so. So overall, it doesn't seem intentional that we didn't
    allow deletions here, either.

Adapt both of these callsites to pass all three sharing flags.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
2024-10-27 19:51:35 -04:00
Taylor Blau
fcaac14abf Merge branch 'sk/msvc-warnings'
Fixes compile time warnings with 64-bit MSVC.

* sk/msvc-warnings:
  mingw.c: Fix complier warnings for a 64 bit msvc
2024-10-25 14:02:44 -04:00
Taylor Blau
4d334e5205 Merge branch 'ak/typofixes'
Typofixes.

* ak/typofixes:
  t: fix typos
  t/helper: fix a typo
  t/perf: fix typos
  t/unit-tests: fix typos
  contrib: fix typos
  compat: fix typos
2024-10-25 14:02:04 -04:00
Sören Krecker
386d372031 mingw.c: Fix complier warnings for a 64 bit msvc
Remove some complier warnings from msvc in compat/mingw.c for value
truncation from 64 bit to 32 bit integers.

Compiling compat/mingw.c under a 64 bit version of msvc produces
warnings. An "int" is 32 bit, and ssize_t or size_t should be 64 bit
long. Prepare compat/vcbuild/include/unistd.h to have a 64 bit type
_ssize_t, when _WIN64 is defined and 32 bit otherwise.

Further down in this include file, as before, ssize_t is defined as
_ssize_t, if needed.

Use size_t instead of int for all variables that hold the result of
strlen() or wcslen() (which cannot be negative).

Use ssize_t to hold the return value of read().

Signed-off-by: Sören Krecker <soekkle@freenet.de>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
2024-10-17 14:42:27 -04:00
Taylor Blau
b43e23fa02 Merge branch 'jk/fsmonitor-event-listener-race-fix'
On macOS, fsmonitor can fall into a race condition that results in
a client waiting forever to be notified for an event that have
already happened.  This problem has been corrected.

* jk/fsmonitor-event-listener-race-fix:
  fsmonitor: initialize fs event listener before accepting clients
  simple-ipc: split async server initialization and running
2024-10-15 16:56:43 -04:00