The Makefile target `install-mingit-test-artifacts` simply copies stuff
and things directly into a MinGit directory, including an init.bat
script to set everything up so that the tests can be run in a cmd
window.
Sadly, Git's test suite still relies on a Perl interpreter even if
compiled with NO_PERL=YesPlease. We punt for now, installing a small
script into /usr/bin/perl that hands off to an existing Perl of a Git
for Windows SDK.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Checking the work tree status is quite slow on Windows, due to slow
`lstat()` emulation (git calls `lstat()` once for each file in the
index). Windows operating system APIs seem to be much better at scanning
the status of entire directories than checking single files.
Add an `lstat()` implementation that uses a cache for lstat data. Cache
misses read the entire parent directory and add it to the cache.
Subsequent `lstat()` calls for the same directory are served directly
from the cache.
Also implement `opendir()`/`readdir()`/`closedir()` so that they create
and use directory listings in the cache.
The cache doesn't track file system changes and doesn't plug into any
modifying file APIs, so it has to be explicitly enabled for git functions
that don't modify the working copy.
Note: in an earlier version of this patch, the cache was always active and
tracked file system changes via ReadDirectoryChangesW. However, this was
much more complex and had negative impact on the performance of modifying
git commands such as 'git checkout'.
Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
As per
https://github.com/git-for-windows/git/issues/4350#issuecomment-1485041503,
the major block for upgrading Git for Windows' OpenSSL from v1.1 to v3
is the tricky part where such an upgrade would break `git fetch`/`git
clone` and `git push` because the libcurl depends on the OpenSSL DLL,
and the major version bump will _change_ the file name of said DLL.
To overcome that, the plan is to build libcurl flavors for each
supported SSL/TLS backend, aligning with the way MSYS2 builds libcurl,
then switch Git for Windows' SDK to the Secure Channel-flavored libcurl,
and teach Git to look for the specific flavor of libcurl corresponding
to the `http.sslBackend` setting (if that was configured).
Here is the PR to teach Git that trick.
It is merely a historical wart that, say, `git-commit` exists in the
`libexec/git-core/` directory, a tribute to the original idea to let Git
be essentially a bunch of Unix shell scripts revolving around very few
"plumbing" (AKA low-level) commands.
Git has evolved a lot from there. These days, most of Git's
functionality is contained within the `git` executable, in the form of
"built-in" commands.
To accommodate for scripts that use the "dashed" form of Git commands,
even today, Git provides hard-links that make the `git` executable
available as, say, `git-commit`, just in case that an old script has not
been updated to invoke `git commit`.
Those hard-links do not come cheap: they take about half a minute for
every build of Git on Windows, they are mistaken for taking up huge
amounts of space by some Windows Explorer versions that do not
understand hard-links, and therefore many a "bug" report had to be
addressed.
The "dashed form" has been officially deprecated in Git version 1.5.4,
which was released on February 2nd, 2008, i.e. a very long time ago.
This deprecation was never finalized by skipping these hard-links, but
we can start the process now, in Git for Windows.
This addresses the concern raised in
https://github.com/git-for-windows/git/pull/4185#discussion_r1051661894
**This requires an ARM64-machine with Windows 11 installed (which
supports x64 emulation for MSYS2)**
### The main idea
- Use the main MSYS2/git-sdk-64 setup, which works on Windows 11 on ARM
thanks to x64-emulation
- Configure the official `clangarm64` MSYS2 repo
- Install `mingw-w64-clang-aarch64-toolchain` which contains the
ARM64-native Clang compiler
Backport a couple fixes to make the CI build run again (so much for
reproducible builds...).
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
This will help with Git for Windows' maintenance going forward: It
allows Git for Windows to switch its primary libcurl to a variant
without the OpenSSL backend, while still loading an alternate when
setting `http.sslBackend = openssl`.
This is necessary to avoid maintenance headaches with upgrading OpenSSL:
its major version name is encoded in the shared library's file name and
hence major version updates (temporarily) break libraries that are
linked against the OpenSSL library.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
It is merely a historical wart that, say, `git-commit` exists in the
`libexec/git-core/` directory, a tribute to the original idea to let Git
be essentially a bunch of Unix shell scripts revolving around very few
"plumbing" (AKA low-level) commands.
Git has evolved a lot from there. These days, most of Git's
functionality is contained within the `git` executable, in the form of
"built-in" commands.
To accommodate for scripts that use the "dashed" form of Git commands,
even today, Git provides hard-links that make the `git` executable
available as, say, `git-commit`, just in case that an old script has not
been updated to invoke `git commit`.
Those hard-links do not come cheap: they take about half a minute for
every build of Git on Windows, they are mistaken for taking up huge
amounts of space by some Windows Explorer versions that do not
understand hard-links, and therefore many a "bug" report had to be
addressed.
The "dashed form" has been officially deprecated in Git version 1.5.4,
which was released on February 2nd, 2008, i.e. a very long time ago.
This deprecation was never finalized by skipping these hard-links, but
we can start the process now, in Git for Windows.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Whith Windows 2000, Microsoft introduced a flag to the PE header to mark executables as
"terminal server aware". Windows terminal servers provide a redirected Windows directory and
redirected registry hives when launching legacy applications without this flag set. Since we
do not use any INI files in the Windows directory and don't write to the registry, we don't
need this additional preparation. Telling the OS that we don't need this should provide
slightly improved startup times in terminal server environments.
When building for supported Windows Versions with MSVC the /TSAWARE linker flag is
automatically set, but MinGW requires us to set the --tsaware flag manually.
This partially addresses https://github.com/git-for-windows/git/issues/3935.
Signed-off-by: Matthias Aßhauer <mha1993@live.de>
CLANGARM64 is a relatively new MSYSTEM added by the MSYS2 team. In order
to have Git build correctly for this platform, let's add some
configuration for it to config.mak.uname.
Signed-off-by: Dennis Ameling <dennis@dennisameling.com>
On Windows, there are two kinds of executables, console ones and
non-console ones. Git's executables are all console ones.
When launching the former e.g. in a scheduled task, a CMD window pops
up. This is not what we want for the tasks installed via the `git
maintenance` command.
To work around this, let's introduce `headless-git.exe`, which is a
non-console program that does _not_ pop up any window. All it does is to
re-launch `git.exe`, suppressing that console window, passing through
all command-line arguments as-are.
Helped-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Helped-by: Yuyi Wang <Strawberry_Str@hotmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
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>
Teach MSVC=1 builds to depend on the `git.rc` file so that
the resulting executables have Windows-style resources and
version number information within them.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
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>
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>
It already caused problems with the test suite that the directory
containing `git.vcxproj` is called the same as the Git executable
without its file extension: `./git` is ambiguous, it could refer both to
the directory `git/` as well as to `git.exe`.
Now there is one more problem: when our GitHub workflow runs on the
`vs/master` branch, it fails in all but the Windows builds, as they want
to write the file `git` but there is already a directory in the way.
Let's just go ahead and append `.proj` to all of those directories, e.g.
`git.proj/` instead of `git/`.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Thorough benchmarking with repacking a subset of linux.git (the commit
history reachable from 93a6fefe2f ([PATCH] fix the SYSCTL=n compilation,
2007-02-28), to be precise) suggest that this allocator is on par, in
multi-threaded situations maybe even better than nedmalloc:
`git repack -adfq` with mimalloc, 8 threads:
31.166991900 27.576763800 28.712311000 27.373859000 27.163141900
`git repack -adfq` with nedmalloc, 8 threads:
31.915032900 27.149883100 28.244933700 27.240188800 28.580849500
In a different test using GitHub Actions build agents (probably
single-threaded, a core-strength of nedmalloc)):
`git repack -q -d -l -A --unpack-unreachable=2.weeks.ago` with mimalloc:
943.426 978.500 939.709 959.811 954.605
`git repack -q -d -l -A --unpack-unreachable=2.weeks.ago` with nedmalloc:
995.383 952.179 943.253 963.043 980.468
While these measurements were not executed with complete scientific
rigor, as no hardware was set aside specifically for these benchmarks,
it shows that mimalloc and nedmalloc perform almost the same, nedmalloc
with a bit higher variance and also slightly higher average (further
testing suggests that nedmalloc performs worse in multi-threaded
situations than in single-threaded ones).
In short: mimalloc seems to be slightly better suited for our purposes
than nedmalloc.
Seeing that mimalloc is developed actively, while nedmalloc ceased to
see any updates in eight years, let's use mimalloc on Windows instead.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
By defining `USE_MIMALLOC`, Git can now be compiled with that
nicely-fast and small allocator.
Note that we have to disable a couple `DEVELOPER` options to build
mimalloc's source code, as it makes heavy use of declarations after
statements, among other things that disagree with Git's conventions.
We even have to silence some GCC warnings in non-DEVELOPER mode. For
example, the `-Wno-array-bounds` flag is needed because in `-O2` builds,
trying to call `NtCurrentTeb()` (which `_mi_thread_id()` does on
Windows) causes the bogus warning about a system header, likely related
to https://sourceforge.net/p/mingw-w64/mailman/message/37674519/ and to
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578:
C:/git-sdk-64-minimal/mingw64/include/psdk_inc/intrin-impl.h:838:1:
error: array subscript 0 is outside array bounds of 'long long unsigned int[0]' [-Werror=array-bounds]
838 | __buildreadseg(__readgsqword, unsigned __int64, "gs", "q")
| ^~~~~~~~~~~~~~
Also: The `mimalloc` library uses C11-style atomics, therefore we must
require that standard when compiling with GCC if we want to use
`mimalloc` (instead of requiring "only" C99). This is what we do in the
CMake definition already, therefore this commit does not need to touch
`contrib/buildsystems/`.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
While Git for Windows does not _ship_ Python (in order to save on
bandwidth), MSYS2 provides very fine Python interpreters that users can
easily take advantage of, by using Git for Windows within its SDK.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Remove support for MSys, which now lags way behind MSys2.
* hj/remove-msys-support:
mingw: remove msysGit/MSYS1 support
mingw: remove duplicate `USE_NED_ALLOCATOR` directive
MSys has long fallen behind MSYS2 in features like Unicode or
x86_64 support or even security bug fixes, and is therefore no
longer used by anyone in the Git developer community. The Git for
Windows project itself started switching from MSys to MSYS2 early
in 2015, i.e. about eight years ago. Let's drop supporting MSys as
a development platform.
Signed-off-by: Harshil-Jani <harshiljani2002@gmail.com>
Acked-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
nedalloc was added to fix the slowness of memory allocator. Here
specifically for the MSys2 build there seems to be a duplication of
USE_NED_ALLOCATOR directive. So this patch intends to remove the
duplicate USE_NED_ALLOCATOR and keeping it only into the MSys2 config
section so it still uses the nedalloc.
Signed-off-by: Harshil-Jani <harshiljani2002@gmail.com>
Acked-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When 1819ad327b (grep: fix multibyte regex handling under macOS,
2022-08-26) started to use the native regex library instead of Git's
own (compat/regex/), it lost support for alternation in basic
regular expressions.
Bring it back by enabling the flag REG_ENHANCED on macOS when
compiling basic regular expressions.
Reported-by: Marco Nenciarini <marco.nenciarini@enterprisedb.com>
Suggested-by: Jeff King <peff@peff.net>
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In df5218b4c3 (config.mak.uname: support MSys2, 2016-01-13), we
introduced support for building Git for Windows in the then-brand new
Git for Windows v2.x build environment that was based off of MSYS2.
To do that, we split the non-msysGit part (that targeted MSys1) in two,
and instead of sharing the `NO_CURL = YesPlease` setting with MSys1, we
overrode it for MSYS2 with the empty value because we very much want to
build Git for Windows with libcurl.
But that was unnecessary: we never set that variable beforehand,
therefore there is no need to override it.
Let's just remove that unnecessary line.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In f9206ce268 (mingw: let's use gettext with MSYS2, 2016-01-26), we
flipped the switch to build Git for Windows with support for gettext.
However, the way we flipped the switch was by changing the value of the
`NO_GETTEXT` variable from a non-empty string to the empty string, as if
there was any `NO_GETTEXT` definition we needed to override.
But that was a mistake: while there _is_ a definition, it is in the
`THIS_IS_MSYSGIT` section, i.e. it does not affect the Git for Windows
part at all.
Let's just remove that unnecessary line.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
While Git for Windows does not _ship_ Python (in order to save on
bandwidth), MSYS2 provides very fine Python interpreters that users can
easily take advantage of, by using Git for Windows within its SDK.
Previously, we excluded the Python bits, mostly due to historical
reasons: In the Git for Windows v1.x days, we built Git using
MSys/MinGW, without support for any Python scripts.
Therefore, let's move out the `NO_PYTHON` definition from the generic
part of the MINGW section (which includes special handling for MSYS2/Git
for Windows, for the long-superseded msysGit environment, as well as for
the setup of probably just one developer remaining with their MSys1)
into the two sections that cover different environments than Git for
Windows' SDK.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
More fsmonitor--daemon.
* jh/builtin-fsmonitor-part3: (30 commits)
t7527: improve implicit shutdown testing in fsmonitor--daemon
fsmonitor--daemon: allow --super-prefix argument
t7527: test Unicode NFC/NFD handling on MacOS
t/lib-unicode-nfc-nfd: helper prereqs for testing unicode nfc/nfd
t/helper/hexdump: add helper to print hexdump of stdin
fsmonitor: on macOS also emit NFC spelling for NFD pathname
t7527: test FSMonitor on case insensitive+preserving file system
fsmonitor: never set CE_FSMONITOR_VALID on submodules
t/perf/p7527: add perf test for builtin FSMonitor
t7527: FSMonitor tests for directory moves
fsmonitor: optimize processing of directory events
fsm-listen-darwin: shutdown daemon if worktree root is moved/renamed
fsm-health-win32: force shutdown daemon if worktree root moves
fsm-health-win32: add polling framework to monitor daemon health
fsmonitor--daemon: stub in health thread
fsmonitor--daemon: rename listener thread related variables
fsmonitor--daemon: prepare for adding health thread
fsmonitor--daemon: cd out of worktree root
fsm-listen-darwin: ignore FSEvents caused by xattr changes on macOS
unpack-trees: initialize fsmonitor_has_run_once in o->result
...
Extend generic incompatibility checkout with platform-specific
mechanism. Stub in Win32 version.
In the existing fsmonitor-settings code we have a way to mark
types of repos as incompatible with fsmonitor (whether via the
hook and IPC APIs). For example, we do this for bare repos,
since there are no files to watch.
Extend this exclusion mechanism for platform-specific reasons.
This commit just creates the framework and adds a stub for Win32.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Built-in fsmonitor (part 2).
* jh/builtin-fsmonitor-part2: (30 commits)
t7527: test status with untracked-cache and fsmonitor--daemon
fsmonitor: force update index after large responses
fsmonitor--daemon: use a cookie file to sync with file system
fsmonitor--daemon: periodically truncate list of modified files
t/perf/p7519: add fsmonitor--daemon test cases
t/perf/p7519: speed up test on Windows
t/perf/p7519: fix coding style
t/helper/test-chmtime: skip directories on Windows
t/perf: avoid copying builtin fsmonitor files into test repo
t7527: create test for fsmonitor--daemon
t/helper/fsmonitor-client: create IPC client to talk to FSMonitor Daemon
help: include fsmonitor--daemon feature flag in version info
fsmonitor--daemon: implement handle_client callback
compat/fsmonitor/fsm-listen-darwin: implement FSEvent listener on MacOS
compat/fsmonitor/fsm-listen-darwin: add MacOS header files for FSEvent
compat/fsmonitor/fsm-listen-win32: implement FSMonitor backend on Windows
fsmonitor--daemon: create token-based changed path cache
fsmonitor--daemon: define token-ids
fsmonitor--daemon: add pathname classification
fsmonitor--daemon: implement 'start' command
...
Replace core.fsyncObjectFiles with two new configuration variables,
core.fsync and core.fsyncMethod.
* ns/core-fsyncmethod:
core.fsync: documentation and user-friendly aggregate options
core.fsync: new option to harden the index
core.fsync: add configuration parsing
core.fsync: introduce granular fsync control infrastructure
core.fsyncmethod: add writeout-only mode
wrapper: make inclusion of Windows csprng header tightly scoped
Stub in empty implementation of fsmonitor--daemon
backend for Darwin (aka MacOS).
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Stub in empty filesystem listener backend for fsmonitor--daemon on Windows.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit introduces the `core.fsyncMethod` configuration
knob, which can currently be set to `fsync` or `writeout-only`.
The new writeout-only mode attempts to tell the operating system to
flush its in-memory page cache to the storage hardware without issuing a
CACHE_FLUSH command to the storage controller.
Writeout-only fsync is significantly faster than a vanilla fsync on
common hardware, since data is written to a disk-side cache rather than
all the way to a durable medium. Later changes in this patch series will
take advantage of this primitive to implement batching of hardware
flushes.
When git_fsync is called with FSYNC_WRITEOUT_ONLY, it may fail and the
caller is expected to do an ordinary fsync as needed.
On Apple platforms, the fsync system call does not issue a CACHE_FLUSH
directive to the storage controller. This change updates fsync to do
fcntl(F_FULLFSYNC) to make fsync actually durable. We maintain parity
with existing behavior on Apple platforms by setting the default value
of the new core.fsyncMethod option.
Signed-off-by: Neeraj Singh <neerajsi@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The $(QUIET) variables we define are largely duplicated between our
various Makefiles, let's define them in the new "shared.mak" instead.
Since we're not using the environment to pass these around we don't
need to export the "QUIET_GEN" and "QUIET_BUILT_IN" variables
anymore. The "QUIET_GEN" variable is used in "git-gui/Makefile" and
"gitweb/Makefile", but they've got their own definition for those. The
"QUIET_BUILT_IN" variable is only used in the top-level "Makefile". We
still need to export the "V" variable.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The build procedure has been taught to notice older version of zlib
and enable our replacement uncompress2() automatically.
* ab/auto-detect-zlib-compress2:
compat: auto-detect if zlib has uncompress2()
Pick a better random number generator and use it when we prepare
temporary filenames.
* bc/csprng-mktemps:
wrapper: use a CSPRNG to generate random file names
wrapper: add a helper to generate numbers from a CSPRNG
We have a copy of uncompress2() implementation in compat/ so that we
can build with an older version of zlib that lack the function, and
the build procedure selects if it is used via the NO_UNCOMPRESS2
$(MAKE) variable. This is yet another "annoying" knob the porters
need to tweak on platforms that are not common enough to have the
default set in the config.mak.uname file.
Attempt to instead ask the system header <zlib.h> to decide if we
need the compatibility implementation. This is a deviation from the
way we have been handling the "compatiblity" features so far, and if
it can be done cleanly enough, it could work as a model for features
that need compatibility definition we discover in the future. With
that goal in mind, avoid expedient but ugly hacks, like shoving the
code that is conditionally compiled into an unrelated .c file, which
may not work in future cases---instead, take an approach that uses a
file that is independently compiled and stands on its own.
Compile and link compat/zlib-uncompress2.c file unconditionally, but
conditionally hide the implementation behind #if/#endif when zlib
version is 1.2.9 or newer, and unconditionally archive the resulting
object file in the libgit.a to be picked up by the linker.
There are a few things to note in the shape of the code base after
this change:
- We no longer use NO_UNCOMPRESS2 knob; if the system header
<zlib.h> claims a version that is more cent than the library
actually is, this would break, but it is easy to add it back when
we find such a system.
- The object file compat/zlib-uncompress2.o is always compiled and
archived in libgit.a, just like a few other compat/ object files
already are.
- The inclusion of <zlib.h> is done in <git-compat-util.h>; we used
to do so from <cache.h> which includes <git-compat-util.h> as the
first thing it does, so from the *.c codes, there is no practical
change.
- Until objects in libgit.a that is already used gains a reference
to the function, the reftable code will be the only one that
wants it, so libgit.a on the linker command line needs to appear
once more at the end to satisify the mutual dependency.
- Beat found a trick used by OpenSSL to avoid making the
conditionally-compiled object truly empty (apparently because
they had to deal with compilers that do not want to see an
effectively empty input file). Our compat/zlib-uncompress2.c
file borrows the same trick for portabilty.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Helped-by: Beat Bolli <dev+git@drbeat.li>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Adjust build on RHEL 7 to explicitly ask C99 support and use
the fallback implementation of uncompress2 we ship.
* da/rhel7-lacks-uncompress2-and-c99:
build: centos/RHEL 7 ships with an older gcc and zlib
There are many situations in which having access to a cryptographically
secure pseudorandom number generator (CSPRNG) is helpful. In the
future, we'll encounter one of these when dealing with temporary files.
To make this possible, let's add a function which reads from a system
CSPRNG and returns some bytes.
We know that all systems will have such an interface. A CSPRNG is
required for a secure TLS or SSH implementation and a Git implementation
which provided neither would be of little practical use. In addition,
POSIX is set to standardize getentropy(2) in the next version, so in the
(potentially distant) future we can rely on that.
For systems which lack one of the other interfaces, we provide the
ability to use OpenSSL's CSPRNG. OpenSSL is highly portable and
functions on practically every known OS, and we know it will have access
to some source of cryptographically secure randomness. We also provide
support for the arc4random in libbsd for folks who would prefer to use
that.
Because this is a security sensitive interface, we take some
precautions. We either succeed by filling the buffer completely as we
requested, or we fail. We don't return partial data because the caller
will almost never find that to be a useful behavior.
Specify a makefile knob which users can use to specify one or more
suitable CSPRNGs, and turn the multiple string options into a set of
defines, since we cannot match on strings in the preprocessor. We allow
multiple options to make the job of handling this in autoconf easier.
The order of options is important here. On systems with arc4random,
which is most of the BSDs, we use that, since, except on MirBSD and
macOS, it uses ChaCha20, which is extremely fast, and sits entirely in
userspace, avoiding a system call. We then prefer getrandom over
getentropy, because the former has been available longer on Linux, and
then OpenSSL. Finally, if none of those are available, we use
/dev/urandom, because most Unix-like operating systems provide that API.
We prefer options that don't involve device files when possible because
those work in some restricted environments where device files may not be
available.
Set the configuration variables appropriately for Linux and the BSDs,
including macOS, as well as Windows and NonStop. We specifically only
consider versions which receive publicly available security support
here. For the same reason, we don't specify getrandom(2) on Linux,
because CentOS 7 doesn't support it in glibc (although its kernel does)
and we don't want to resort to making syscalls.
Finally, add a test helper to allow this to be tested by hand and in
tests. We don't add any tests, since invoking the CSPRNG is not likely
to produce interesting, reproducible results.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
GCC 4.8.5 is the default system compiler on centos7/RHEL7.
This version requires -std=c99 to enable c99 support.
zlib 1.2.7 on centos7/rhel7 lacks uncompress2().
Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Notably, it lacks uncompress2(); use the fallback we ship in our
tree instead.
Signed-off-by: Randall S. Becker <rsbecker@nexbridge.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The "reftable" backend for the refs API, without integrating into
the refs subsystem, has been added.
* hn/reftable:
Add "test-tool dump-reftable" command.
reftable: add dump utility
reftable: implement stack, a mutable database of reftable files.
reftable: implement refname validation
reftable: add merged table view
reftable: add a heap-based priority queue for reftable records
reftable: reftable file level tests
reftable: read reftable files
reftable: generic interface to tables
reftable: write reftable files
reftable: a generic binary tree implementation
reftable: reading/writing blocks
Provide zlib's uncompress2 from compat/zlib-compat.c
reftable: (de)serialization for the polymorphic record type.
reftable: add blocksource, an abstraction for random access reads
reftable: utility functions
reftable: add error related functionality
reftable: add LICENSE
hash.h: provide constants for the hash IDs
Johannes Schindelin
Karsten Blees
Matthias Aßhauer
Dennis Ameling
Jeff Hostetler
Junio C Hamano
Harshil-Jani
René Scharfe
Neeraj Singh
Ævar Arnfjörð Bjarmason
brian m. carlson
David Aguilar
Randall S. Becker