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Compilation fix around type punning.
* jk/drop-unaligned-loads:
Revert "fast-export: use local array to store anonymized oid"
bswap.h: drop unaligned loads
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Our put_be32() routine and its variants (get_be32(), put_be64(), etc)
has two implementations: on some platforms we cast memory in place and
use nothl()/htonl(), which can cause unaligned memory access. And on
others, we pick out the individual bytes using bitshifts.
This introduces extra complexity, and sometimes causes compilers to
generate warnings about type-punning. And it's not clear there's any
performance advantage.
This split goes back to 660231aa97 (block-sha1: support for
architectures with memory alignment restrictions, 2009-08-12). The
unaligned versions were part of the original block-sha1 code in
d7c208a92e (Add new optimized C 'block-sha1' routines, 2009-08-05),
which says it is:
Based on the mozilla SHA1 routine, but doing the input data accesses a
word at a time and with 'htonl()' instead of loading bytes and shifting.
Back then, Linus provided timings versus the mozilla code which showed a
27% improvement:
https://lore.kernel.org/git/alpine.LFD.2.01.0908051545000.3390@localhost.localdomain/
However, the unaligned loads were either not the useful part of that
speedup, or perhaps compilers and processors have changed since then.
Here are times for computing the sha1 of 4GB of random data, with and
without -DNO_UNALIGNED_LOADS (and BLK_SHA1=1, of course). This is with
gcc 10, -O2, and the processor is a Core i9-9880H.
[stock]
Benchmark #1: t/helper/test-tool sha1 <foo.rand
Time (mean ± σ): 6.638 s ± 0.081 s [User: 6.269 s, System: 0.368 s]
Range (min … max): 6.550 s … 6.841 s 10 runs
[-DNO_UNALIGNED_LOADS]
Benchmark #1: t/helper/test-tool sha1 <foo.rand
Time (mean ± σ): 6.418 s ± 0.015 s [User: 6.058 s, System: 0.360 s]
Range (min … max): 6.394 s … 6.447 s 10 runs
And here's the same test run on an AMD A8-7600, using gcc 8.
[stock]
Benchmark #1: t/helper/test-tool sha1 <foo.rand
Time (mean ± σ): 11.721 s ± 0.113 s [User: 10.761 s, System: 0.951 s]
Range (min … max): 11.509 s … 11.861 s 10 runs
[-DNO_UNALIGNED_LOADS]
Benchmark #1: t/helper/test-tool sha1 <foo.rand
Time (mean ± σ): 11.744 s ± 0.066 s [User: 10.807 s, System: 0.928 s]
Range (min … max): 11.637 s … 11.863 s 10 runs
So the unaligned loads don't seem to help much, and actually make things
worse. It's possible there are platforms where they provide more
benefit, but:
- the non-x86 platforms for which we use this code are old and obscure
(powerpc and s390).
- the main caller that cares about performance is block-sha1. But
these days it is rarely used anyway, in favor of sha1dc (which is
already much slower, and nobody seems to have cared that much).
Let's just drop unaligned versions entirely in the name of simplicity.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Signed-off-by: Orgad Shaneh <orgads@gmail.com>
Acked-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Signed-off-by: Orgad Shaneh <orgads@gmail.com>
Acked-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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"unlink" emulation on MinGW has been optimized.
* jh/mingw-unlink:
mingw: improve performance of mingw_unlink()
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Update mingw_unlink() to first try to delete the file with existing
permissions before trying to force it.
Windows throws an error when trying to delete a read-only file. The
mingw_unlink() compatibility wrapper always tries to _wchmod(666) the
file before calling _wunlink() to avoid that error. However, since
most files in the worktree are already writable, this is usually
wasted effort.
Update mingw_unlink() to just call DeleteFileW() directly and if that
succeeds return. If that fails, fall back into the existing code path
to update the permissions and use _wunlink() to get the existing
error code mapping.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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We eventually want to drop the argv_array name and just use strvec
consistently. There's no particular reason we have to do it all at once,
or care about interactions between converted and unconverted bits.
Because of our preprocessor compat layer, the names are interchangeable
to the compiler (so even a definition and declaration using different
names is OK).
This patch converts remaining files from the first half of the alphabet,
to keep the diff to a manageable size.
The conversion was done purely mechanically with:
git ls-files '*.c' '*.h' |
xargs perl -i -pe '
s/ARGV_ARRAY/STRVEC/g;
s/argv_array/strvec/g;
'
and then selectively staging files with "git add '[abcdefghjkl]*'".
We'll deal with any indentation/style fallouts separately.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Workaround breakage in MSVC build, where "curl-config --cflags"
gives settings appropriate for GCC build.
* js/msvc-build-fix:
msvc: fix "REG_STARTEND" issue
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In 897d68e7af82 (Makefile: use curl-config --cflags, 2020-03-26), we
taught the build process to use `curl-config --cflags` to make sure that
it can find cURL's headers.
In the MSVC build, this is completely bogus because we're running in a
Git for Windows SDK whose `curl-config` supports the _GCC_ build.
Let's just ignore each and every `-I<path>` option where `<path>` points
to GCC/Clang specific headers.
Reported by Jeff Hostetler in
https://github.com/microsoft/git/issues/275.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Code clean-up by removing a compatibility implementation of a
function we no longer use.
* cb/no-more-gmtime:
compat: remove gmtime
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ccd469450a (date.c: switch to reentrant {gm,local}time_r, 2019-11-28)
removes the only gmtime() call we had and moves to gmtime_r() which
doesn't have the same portability problems.
Remove the compat gmtime code since it is no longer needed, and confirm
by successfull running t4212 in FreeBSD 9.3 amd64 (the oldest I could
get a hold off).
Further work might be needed to ensure 32bit time_t systems (like FreeBSD
i386) will handle correctly the overflows tested in t4212, but that is
orthogonal to this change, and it doesn't change the current behaviour
as neither gmtime() or gmtime_r() will ever return NULL on those systems
because time_t is unsigned.
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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The "bugreport" tool.
* es/bugreport:
bugreport: drop extraneous includes
bugreport: add compiler info
bugreport: add uname info
bugreport: gather git version and build info
bugreport: add tool to generate debugging info
help: move list_config_help to builtin/help
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In Linux with musl libc, we have this inclusion chain:
compat/regex/regex.c:69
`-> compat/regex/regex_internal.h
`-> /usr/include/stdlib.h
`-> /usr/include/features.h
`-> /usr/include/alloca.h
In that inclusion chain, `<features.h>` claims it's _BSD_SOURCE
compatible when it's NOT asked to be either
{_POSIX,_GNU,_XOPEN,_BSD}_SOURCE, or __STRICT_ANSI__.
And, `<stdlib.h>` will include `<alloca.h>` to be compatible with
software written for GNU and BSD. Thus, redefine `alloca` macro,
which was defined before at compat/regex/regex.c:66.
Considering this is only compat code, we've taken from other project,
it's not our business to decide which source should we adhere to.
Include `<stdlib.h>` early to prevent the redefinition of alloca.
This also remove a potential warning about alloca not defined on:
#undef alloca
Helped-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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* js/mingw-isilon-nfs:
mingw: cope with the Isilon network file system
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Misc fixes for Windows.
* js/mingw-fixes:
mingw: help debugging by optionally executing bash with strace
mingw: do not treat `COM0` as a reserved file name
mingw: use modern strftime implementation if possible
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To help pinpoint the source of a regression, it is useful to know some
info about the compiler which the user's Git client was built with. By
adding a generic get_compiler_info() in 'compat/' we can choose which
relevant information to share per compiler; to get started, let's
demonstrate the version of glibc if the user built with 'gcc'.
Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
Helped-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Starting in 3ac68a93fd2, help.o began to depend on builtin/branch.o,
builtin/clean.o, and builtin/config.o. This meant that help.o was
unusable outside of the context of the main Git executable.
To make help.o usable by other commands again, move list_config_help()
into builtin/help.c (where it makes sense to assume other builtin libraries
are present).
When command-list.h is included but a member is not used, we start to
hear a compiler warning. Since the config list is generated in a fairly
different way than the command list, and since commands and config
options are semantically different, move the config list into its own
header and move the generator into its own script and build rule.
For reasons explained in 976aaedc (msvc: add a Makefile target to
pre-generate the Visual Studio solution, 2019-07-29), some build
artifacts we consider non-source files cannot be generated in the
Visual Studio environment, and we already have some Makefile tweaks
to help Visual Studio to use generated command-list.h header file.
Do the same to a new generated file, config-list.h, introduced by
this change.
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
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On certain network filesystems (currently encountered with Isilon, but
in theory more network storage solutions could be causing the same
issue), when the directory in question is missing,
`raceproof_create_file()` fails with an `ERROR_INVALID_PARAMETER`
instead of an `ERROR_PATH_NOT_FOUND`.
Since it is highly unlikely that we produce such an error by mistake
(the parameters we pass are fairly benign), we can be relatively certain
that the directory is missing in this instance. So let's just translate
that error automagically.
This fixes https://github.com/git-for-windows/git/issues/1345.
Signed-off-by: Nathan Sanders <spekbukkem@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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MSYS2's strace facility is very useful for debugging... With this patch,
the bash will be executed through strace if the environment variable
GIT_STRACE_COMMANDS is set, which comes in real handy when investigating
issues in the test suite.
Also support passing a path to a log file via GIT_STRACE_COMMANDS to
force Git to call strace.exe with the `-o <path>` argument, i.e. to log
into a file rather than print the log directly.
That comes in handy when the output would otherwise misinterpreted by a
calling process as part of Git's output.
Note: the values "1", "yes" or "true" are *not* specifying paths, but
tell Git to let strace.exe log directly to the console.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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In 4dc42c6c186 (mingw: refuse paths containing reserved names,
2019-12-21), we started disallowing file names that are reserved, e.g.
`NUL`, `CONOUT$`, etc.
This included `COM<n>` where `<n>` is a digit. Unfortunately, this
includes `COM0` but only `COM1`, ..., `COM9` are reserved, according to
the official documentation, `COM0` is mentioned in the "NT Namespaces"
section but it is explicitly _omitted_ from the list of reserved names:
https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file#naming-conventions
Tests corroborate this: it is totally possible to write a file called
`com0.c` on Windows 10, but not `com1.c`.
So let's tighten the code to disallow only the reserved `COM<n>` file
names, but to allow `COM0` again.
This fixes https://github.com/git-for-windows/git/issues/2470.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Microsoft introduced a new "Universal C Runtime Library" (UCRT) with
Visual Studio 2015. The UCRT comes with a new strftime() implementation
that supports more date formats. We link git against the older
"Microsoft Visual C Runtime Library" (MSVCRT), so to use the UCRT
strftime() we need to load it from ucrtbase.dll using
DECLARE_PROC_ADDR()/INIT_PROC_ADDR().
Most supported Windows systems should have recieved the UCRT via Windows
update, but in some cases only MSVCRT might be available. In that case
we fall back to using that implementation.
With this change, it is possible to use e.g. the `%g` and `%V` date
format specifiers, e.g.
git show -s --format=%cd --date=format:‘%g.%V’ HEAD
Without this change, the user would see this error message on Windows:
fatal: invalid strftime format: '‘%g.%V’'
This fixes https://github.com/git-for-windows/git/issues/2495
Signed-off-by: Matthias Aßhauer <mha1993@live.de>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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On Cygwin, the codepath for POSIX-like systems is taken in
run-command.c::start_command(). The prepare_cmd() helper
function is called to decide if the command needs to be looked
up in the PATH. The logic there is to do the PATH-lookup if
and only if it does not have any slash '/' in it. If this test
passes we end up attempting to run the command by appending the
string after each colon-separated component of PATH.
The Cygwin environment supports both Windows and POSIX style
paths, so both forwardslahes '/' and back slashes '\' can be
used as directory separators for any external program the user
supplies.
Examples for path strings which are being incorrectly searched
for in the PATH instead of being executed as is:
- "C:\Program Files\some-program.exe"
- "a\b\c.exe"
To handle these, the PATH lookup detection logic in prepare_cmd()
is taught to know about this Cygwin quirk, by introducing
has_dir_sep(path) helper function to abstract away the difference
between true POSIX and Cygwin systems.
Signed-off-by: Andras Kucsma <r0maikx02b@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Dev support.
* js/mingw-open-in-gdb:
mingw: add a helper function to attach GDB to the current process
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MinGW's poll() emulation has been improved.
* am/mingw-poll-fix:
mingw: workaround for hangs when sending STDIN
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C pedantry ;-) fix.
* jk/clang-sanitizer-fixes:
obstack: avoid computing offsets from NULL pointer
xdiff: avoid computing non-zero offset from NULL pointer
avoid computing zero offsets from NULL pointer
merge-recursive: use subtraction to flip stage
merge-recursive: silence -Wxor-used-as-pow warning
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MinGW's poll() emulation has been improved.
* am/mingw-poll-fix:
mingw: workaround for hangs when sending STDIN
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Code cleanup.
* rs/micro-cleanups:
use strpbrk(3) to search for characters from a given set
quote: use isalnum() to check for alphanumeric characters
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Explanation
-----------
The problem here is flawed `poll()` implementation. When it tries to
see if pipe can be written without blocking, it eventually calls
`NtQueryInformationFile()` and tests `WriteQuotaAvailable`. However,
the meaning of quota was misunderstood. The value of quota is reduced
when either some data was written to a pipe, *or* there is a pending
read on the pipe. Therefore, if there is a pending read of size >= than
the pipe's buffer size, poll() will think that pipe is not writable and
will hang forever, usually that means deadlocking both pipe users.
I have studied the problem and found that Windows pipes track two values:
`QuotaUsed` and `BytesInQueue`. The code in `poll()` apparently wants to
know `BytesInQueue` instead of quota. Unfortunately, `BytesInQueue` can
only be requested from read end of the pipe, while `poll()` receives
write end.
The git's implementation of `poll()` was copied from gnulib, which also
contains a flawed implementation up to today.
I also had a look at implementation in cygwin, which is also broken in a
subtle way. It uses this code in `pipe_data_available()`:
fpli.WriteQuotaAvailable = (fpli.OutboundQuota - fpli.ReadDataAvailable)
However, `ReadDataAvailable` always returns 0 for the write end of the pipe,
turning the code into an obfuscated version of returning pipe's total
buffer size, which I guess will in turn have `poll()` always say that pipe
is writable. The commit that introduced the code doesn't say anything about
this change, so it could be some debugging code that slipped in.
These are the typical sizes used in git:
0x2000 - default read size in `strbuf_read()`
0x1000 - default read size in CRT, used by `strbuf_getwholeline()`
0x2000 - pipe buffer size in compat\mingw.c
As a consequence, as soon as child process uses `strbuf_read()`,
`poll()` in parent process will hang forever, deadlocking both
processes.
This results in two observable behaviors:
1) If parent process begins sending STDIN quickly (and usually that's
the case), then first `poll()` will succeed and first block will go
through. MAX_IO_SIZE_DEFAULT is 8MB, so if STDIN exceeds 8MB, then
it will deadlock.
2) If parent process waits a little bit for any reason (including OS
scheduler) and child is first to issue `strbuf_read()`, then it will
deadlock immediately even on small STDINs.
The problem is illustrated by `git stash push`, which will currently
read the entire patch into memory and then send it to `git apply` via
STDIN. If patch exceeds 8MB, git hangs on Windows.
Possible solutions
------------------
1) Somehow obtain `BytesInQueue` instead of `QuotaUsed`
I did a pretty thorough search and didn't find any ways to obtain
the value from write end of the pipe.
2) Also give read end of the pipe to `poll()`
That can be done, but it will probably invite some dirty code,
because `poll()`
* can accept multiple pipes at once
* can accept things that are not pipes
* is expected to have a well known signature.
3) Make `poll()` always reply "writable" for write end of the pipe
Afterall it seems that cygwin (accidentally?) does that for years.
Also, it should be noted that `pump_io_round()` writes 8MB blocks,
completely ignoring the fact that pipe's buffer size is only 8KB,
which means that pipe gets clogged many times during that single
write. This may invite a deadlock, if child's STDERR/STDOUT gets
clogged while it's trying to deal with 8MB of STDIN. Such deadlocks
could be defeated with writing less than pipe's buffer size per
round, and always reading everything from STDOUT/STDERR before
starting next round. Therefore, making `poll()` always reply
"writable" shouldn't cause any new issues or block any future
solutions.
4) Increase the size of the pipe's buffer
The difference between `BytesInQueue` and `QuotaUsed` is the size
of pending reads. Therefore, if buffer is bigger than size of reads,
`poll()` won't hang so easily. However, I found that for example
`strbuf_read()` will get more and more hungry as it reads large inputs,
eventually surpassing any reasonable pipe buffer size.
Chosen solution
---------------
Make `poll()` always reply "writable" for write end of the pipe.
Hopefully one day someone will find a way to implement it properly.
Reproduction
------------
printf "%8388608s" X >large_file.txt
git stash push --include-untracked -- large_file.txt
I have decided not to include this as test to avoid slowing down the
test suite. I don't expect the specific problem to come back, and
chances are that `git stash push` will be reworked to avoid sending the
entire patch via STDIN.
Signed-off-by: Alexandr Miloslavskiy <alexandr.miloslavskiy@syntevo.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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We can check if certain characters are present in a string by calling
strchr(3) on each of them, or we can pass them all to a single
strpbrk(3) call. The latter is shorter, less repetitive and slightly
more efficient, so let's do that instead.
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Dev support.
* js/mingw-open-in-gdb:
mingw: add a helper function to attach GDB to the current process
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Work around test breakages caused by custom regex engine used in
libasan, when address sanitizer is used with more recent versions
of gcc and clang.
* jk/asan-build-fix:
Makefile: use compat regex with SANITIZE=address
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When debugging Git, the criss-cross spawning of processes can make
things quite a bit difficult, especially when a Unix shell script is
thrown in the mix that calls a `git.exe` that then segfaults.
To help debugging such things, we introduce the `open_in_gdb()` function
which can be called at a code location where the segfault happens (or as
close as one can get); This will open a new MinTTY window with a GDB
that already attached to the current process.
Inspired by Derrick Stolee.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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C pedantry ;-) fix.
* jk/clang-sanitizer-fixes:
obstack: avoid computing offsets from NULL pointer
xdiff: avoid computing non-zero offset from NULL pointer
avoid computing zero offsets from NULL pointer
merge-recursive: use subtraction to flip stage
merge-recursive: silence -Wxor-used-as-pow warning
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The final leg of rewriting "add -i/-p" in C.
* js/add-p-leftover-bits:
ci: include the built-in `git add -i` in the `linux-gcc` job
built-in add -p: handle Escape sequences more efficiently
built-in add -p: handle Escape sequences in interactive.singlekey mode
built-in add -p: respect the `interactive.singlekey` config setting
terminal: add a new function to read a single keystroke
terminal: accommodate Git for Windows' default terminal
terminal: make the code of disable_echo() reusable
built-in add -p: handle diff.algorithm
built-in add -p: support interactive.diffFilter
t3701: adjust difffilter test
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Work around test breakages caused by custom regex engine used in
libasan, when address sanitizer is used with more recent versions
of gcc and clang.
* jk/asan-build-fix:
Makefile: use compat regex with SANITIZE=address
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As with the previous two commits, UBSan with clang-11 complains about
computing offsets from a NULL pointer. The failures in t4013 (and
elsewhere) look like this:
kwset.c:102:23: runtime error: applying non-zero offset 107820859019600 to null pointer
...
not ok 79 - git log -SF master # magic is (not used)
That line is not enlightening:
... = obstack_alloc(&kwset->obstack, sizeof (struct trie));
because obstack is implemented almost entirely in macros, and the actual
problem is five macros deep (I temporarily converted them to inline
functions to get better compiler errors, which was tedious but worked
reasonably well).
The actual problem is in these pointer-alignment macros:
/* If B is the base of an object addressed by P, return the result of
aligning P to the next multiple of A + 1. B and P must be of type
char *. A + 1 must be a power of 2. */
#define __BPTR_ALIGN(B, P, A) ((B) + (((P) - (B) + (A)) & ~(A)))
/* Similar to _BPTR_ALIGN (B, P, A), except optimize the common case
where pointers can be converted to integers, aligned as integers,
and converted back again. If PTR_INT_TYPE is narrower than a
pointer (e.g., the AS/400), play it safe and compute the alignment
relative to B. Otherwise, use the faster strategy of computing the
alignment relative to 0. */
#define __PTR_ALIGN(B, P, A) \
__BPTR_ALIGN (sizeof (PTR_INT_TYPE) < sizeof (void *) ? (B) : (char *) 0, \
P, A)
If we have a sufficiently-large integer pointer type, then we do the
computation using a NULL pointer constant. That turns __BPTR_ALIGN()
into something like:
NULL + (P - NULL + A) & ~A
and UBSan is complaining about adding the full value of P to that
initial NULL. We can fix this by doing our math as an integer type, and
then casting the result back to a pointer. The problem case only happens
when we know that the integer type is large enough, so there should be
no issue with truncation.
Another option would be just simplify out all the 0's from
__BPTR_ALIGN() for the NULL-pointer case. That probably wouldn't work
for a platform where the NULL pointer isn't all-zeroes, but Git already
wouldn't work on such a platform (due to our use of memset to set
pointers in structs to NULL). But I tried here to keep as close to the
original as possible.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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* maint:
msvc: accommodate for vcpkg's upgrade to OpenSSL v1.1.x
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Recent versions of the gcc and clang Address Sanitizer produce test
failures related to regexec(). This triggers with gcc-10 and clang-8
(but not gcc-9 nor clang-7). Running:
make CC=gcc-10 SANITIZE=address test
results in failures in t4018, t3206, and t4062.
The cause seems to be that when built with ASan, we use a different
version of regexec() than normal. And this version doesn't understand
the REG_STARTEND flag. Here's my evidence supporting that.
The failure in t4062 is an ASan warning:
expecting success of 4062.2 '-G matches':
git diff --name-only -G "^(0{64}){64}$" HEAD^ >out &&
test 4096-zeroes.txt = "$(cat out)"
=================================================================
==672994==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7fa76f672000 at pc 0x7fa7726f75b6 bp 0x7ffe41bdda70 sp 0x7ffe41bdd220
READ of size 4097 at 0x7fa76f672000 thread T0
#0 0x7fa7726f75b5 (/lib/x86_64-linux-gnu/libasan.so.6+0x4f5b5)
#1 0x562ae0c9c40e in regexec_buf /home/peff/compile/git/git-compat-util.h:1117
#2 0x562ae0c9c40e in diff_grep /home/peff/compile/git/diffcore-pickaxe.c:52
#3 0x562ae0c9cc28 in pickaxe_match /home/peff/compile/git/diffcore-pickaxe.c:166
[...]
In this case we're looking in a buffer which was mmap'd via
reuse_worktree_file(), and whose size is 4096 bytes. But libasan's
regex tries to look at byte 4097 anyway! If we tweak Git like this:
diff --git a/diff.c b/diff.c
index 8e2914c031..cfae60c120 100644
--- a/diff.c
+++ b/diff.c
@@ -3880,7 +3880,7 @@ static int reuse_worktree_file(struct index_state *istate,
*/
if (ce_uptodate(ce) ||
(!lstat(name, &st) && !ie_match_stat(istate, ce, &st, 0)))
- return 1;
+ return 0;
return 0;
}
to use a regular buffer (with a trailing NUL) instead of an mmap, then
the complaint goes away.
The other failures are actually diff output with an incorrect funcname
header. If I instrument xdiff to show the funcname matching like so:
diff --git a/xdiff-interface.c b/xdiff-interface.c
index 8509f9ea22..f6c3dc1986 100644
--- a/xdiff-interface.c
+++ b/xdiff-interface.c
@@ -197,6 +197,7 @@ struct ff_regs {
struct ff_reg {
regex_t re;
int negate;
+ char *printable;
} *array;
};
@@ -218,7 +219,12 @@ static long ff_regexp(const char *line, long len,
for (i = 0; i < regs->nr; i++) {
struct ff_reg *reg = regs->array + i;
- if (!regexec_buf(®->re, line, len, 2, pmatch, 0)) {
+ int ret = regexec_buf(®->re, line, len, 2, pmatch, 0);
+ warning("regexec %s:\n regex: %s\n buf: %.*s",
+ ret == 0 ? "matched" : "did not match",
+ reg->printable,
+ (int)len, line);
+ if (!ret) {
if (reg->negate)
return -1;
break;
@@ -264,6 +270,7 @@ void xdiff_set_find_func(xdemitconf_t *xecfg, const char *value, int cflags)
expression = value;
if (regcomp(®->re, expression, cflags))
die("Invalid regexp to look for hunk header: %s", expression);
+ reg->printable = xstrdup(expression);
free(buffer);
value = ep + 1;
}
then when compiling with ASan and gcc-10, running the diff from t4018.66
produces this:
$ git diff -U1 cpp-skip-access-specifiers
warning: regexec did not match:
regex: ^[ ]*[A-Za-z_][A-Za-z_0-9]*:[[:space:]]*($|/[/*])
buf: private:
warning: regexec matched:
regex: ^((::[[:space:]]*)?[A-Za-z_].*)$
buf: private:
diff --git a/cpp-skip-access-specifiers b/cpp-skip-access-specifiers
index 4d4a9db..ebd6f42 100644
--- a/cpp-skip-access-specifiers
+++ b/cpp-skip-access-specifiers
@@ -6,3 +6,3 @@ private:
void DoSomething();
int ChangeMe;
};
void DoSomething();
- int ChangeMe;
+ int IWasChanged;
};
That first regex should match (and is negated, so it should be telling
us _not_ to match "private:"). But it wouldn't if regexec() is looking
at the whole buffer, and not just the length-limited line we've fed to
regexec_buf(). So this is consistent again with REG_STARTEND being
ignored.
The correct output (compiling without ASan, or gcc-9 with Asan) looks
like this:
warning: regexec matched:
regex: ^[ ]*[A-Za-z_][A-Za-z_0-9]*:[[:space:]]*($|/[/*])
buf: private:
[...more lines that we end up not using...]
warning: regexec matched:
regex: ^((::[[:space:]]*)?[A-Za-z_].*)$
buf: class RIGHT : public Baseclass
diff --git a/cpp-skip-access-specifiers b/cpp-skip-access-specifiers
index 4d4a9db..ebd6f42 100644
--- a/cpp-skip-access-specifiers
+++ b/cpp-skip-access-specifiers
@@ -6,3 +6,3 @@ class RIGHT : public Baseclass
void DoSomething();
- int ChangeMe;
+ int IWasChanged;
};
So it really does seem like libasan's regex engine is ignoring
REG_STARTEND. We should be able to work around it by compiling with
NO_REGEX, which would use our local regexec(). But to make matters even
more interesting, this isn't enough by itself.
Because ASan has support from the compiler, it doesn't seem to intercept
our call to regexec() at the dynamic library level. It actually
recognizes when we are compiling a call to regexec() and replaces it
with ASan-specific code at that point. And unlike most of our other
compat code, where we might have git_mmap() or similar, the actual
symbol name in the compiled compat/regex code is regexec(). So just
compiling with NO_REGEX isn't enough; we still end up in libasan!
We can work around that by having the preprocessor replace regexec with
git_regexec (both in the callers and in the actual implementation), and
we truly end up with a call to our custom regex code, even when
compiling with ASan. That's probably a good thing to do anyway, as it
means anybody looking at the symbols later (e.g., in a debugger) would
have a better indication of which function is which. So we'll do the
same for the other common regex functions (even though just regexec() is
enough to fix this ASan problem).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
|
With the upgrade, the library names changed from libeay32/ssleay32 to
libcrypto/libssl.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
|
When `interactive.singlekey = true`, we react immediately to keystrokes,
even to Escape sequences (e.g. when pressing a cursor key).
The problem with Escape sequences is that we do not really know when
they are done, and as a heuristic we poll standard input for half a
second to make sure that we got all of it.
While waiting half a second is not asking for a whole lot, it can become
quite annoying over time, therefore with this patch, we read the
terminal capabilities (if available) and extract known Escape sequences
from there, then stop polling immediately when we detected that the user
pressed a key that generated such a known sequence.
This recapitulates the remaining part of b5cc003253c8 (add -i: ignore
terminal escape sequences, 2011-05-17).
Note: We do *not* query the terminal capabilities directly. That would
either require a lot of platform-specific code, or it would require
linking to a library such as ncurses.
Linking to a library in the built-ins is something we try very hard to
avoid (we even kicked the libcurl dependency to a non-built-in remote
helper, just to shave off a tiny fraction of a second from Git's startup
time). And the platform-specific code would be a maintenance nightmare.
Even worse: in Git for Windows' case, we would need to query MSYS2
pseudo terminals, which `git.exe` simply cannot do (because it is
intentionally *not* an MSYS2 program).
To address this, we simply spawn `infocmp -L -1` and parse its output
(which works even in Git for Windows, because that helper is included in
the end-user facing installations).
This is done only once, as in the Perl version, but it is done only when
the first Escape sequence is encountered, not upon startup of `git add
-i`; This saves on startup time, yet makes reacting to the first Escape
sequence slightly more sluggish. But it allows us to keep the
terminal-related code encapsulated in the `compat/terminal.c` file.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
|
This recapitulates part of b5cc003253c8 (add -i: ignore terminal escape
sequences, 2011-05-17):
add -i: ignore terminal escape sequences
On the author's terminal, the up-arrow input sequence is ^[[A, and
thus fat-fingering an up-arrow into 'git checkout -p' is quite
dangerous: git-add--interactive.perl will ignore the ^[ and [
characters and happily treat A as "discard everything".
As a band-aid fix, use Term::Cap to get all terminal capabilities.
Then use the heuristic that any capability value that starts with ^[
(i.e., \e in perl) must be a key input sequence. Finally, given an
input that starts with ^[, read more characters until we have read a
full escape sequence, then return that to the caller. We use a
timeout of 0.5 seconds on the subsequent reads to avoid getting stuck
if the user actually input a lone ^[.
Since none of the currently recognized keys start with ^[, the net
result is that the sequence as a whole will be ignored and the help
displayed.
Note that we leave part for later which uses "Term::Cap to get all
terminal capabilities", for several reasons:
1. it is actually not really necessary, as the timeout of 0.5 seconds
should be plenty sufficient to catch Escape sequences,
2. it is cleaner to keep the change to special-case Escape sequences
separate from the change that reads all terminal capabilities to
speed things up, and
3. in practice, relying on the terminal capabilities is a bit overrated,
as the information could be incomplete, or plain wrong. For example,
in this developer's tmux sessions, the terminal capabilities claim
that the "cursor up" sequence is ^[M, but the actual sequence
produced by the "cursor up" key is ^[[A.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
|
Typically, input on the command-line is line-based. It is actually not
really easy to get single characters (or better put: keystrokes).
We provide two implementations here:
- One that handles `/dev/tty` based systems as well as native Windows.
The former uses the `tcsetattr()` function to put the terminal into
"raw mode", which allows us to read individual keystrokes, one by one.
The latter uses `stty.exe` to do the same, falling back to direct
Win32 Console access.
Thanks to the refactoring leading up to this commit, this is a single
function, with the platform-specific details hidden away in
conditionally-compiled code blocks.
- A fall-back which simply punts and reads back an entire line.
Note that the function writes the keystroke into an `strbuf` rather than
a `char`, in preparation for reading Escape sequences (e.g. when the
user hit an arrow key). This is also required for UTF-8 sequences in
case the keystroke corresponds to a non-ASCII letter.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
|
Git for Windows' Git Bash runs in MinTTY by default, which does not have
a Win32 Console instance, but uses MSYS2 pseudo terminals instead.
This is a problem, as Git for Windows does not want to use the MSYS2
emulation layer for Git itself, and therefore has no direct way to
interact with that pseudo terminal.
As a workaround, use the `stty` utility (which is included in Git for
Windows, and which *is* an MSYS2 program, so it knows how to deal with
the pseudo terminal).
Note: If Git runs in a regular CMD or PowerShell window, there *is* a
regular Win32 Console to work with. This is not a problem for the MSYS2
`stty`: it copes with this scenario just fine.
Also note that we introduce support for more bits than would be
necessary for a mere `disable_echo()` here, in preparation for the
upcoming `enable_non_canonical()` function.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
|
We are about to introduce the function `enable_non_canonical()`, which
shares almost the complete code with `disable_echo()`.
Let's prepare for that, by refactoring out that shared code.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
|
Forbid pathnames that the platform's filesystem cannot represent on
MinGW.
* js/mingw-reserved-filenames:
mingw: refuse paths containing reserved names
mingw: short-circuit the conversion of `/dev/null` to UTF-16
|
|
There are a couple of reserved names that cannot be file names on
Windows, such as `AUX`, `NUL`, etc. For an almost complete list, see
https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file
If one would try to create a directory named `NUL`, it would actually
"succeed", i.e. the call would return success, but nothing would be
created.
Worse, even adding a file extension to the reserved name does not make
it a valid file name. To understand the rationale behind that behavior,
see https://devblogs.microsoft.com/oldnewthing/20031022-00/?p=42073
Let's just disallow them all.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
|
In the next commit, we want to disallow accessing any path that contains
any segment that is equivalent to `NUL`. In particular, we want to
disallow accessing `NUL` (e.g. to prevent any repository from being
checked out that contains a file called `NUL`, as that is not a valid
file name on Windows).
However, there are legitimate use cases within Git itself to write to
the Null device. As Git is really a Linux project, it does not abstract
that idea, though, but instead uses `/dev/null` to describe this
intention.
So let's side-step the validation _specifically_ in the case that we
want to write to (or read from) `/dev/null`, via a dedicated short-cut
in the code that skips the call to `validate_win32_path()`.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
|
|
Avoid gmtime() and localtime() and prefer their reentrant
counterparts.
* dd/time-reentrancy:
mingw: use {gm,local}time_s as backend for {gm,local}time_r
archive-zip.c: switch to reentrant localtime_r
date.c: switch to reentrant {gm,local}time_r
|
|
Work around a issue where a FD that is left open when spawning a
child process and is kept open in the child can interfere with the
operation in the parent process on Windows.
* js/mingw-inherit-only-std-handles:
mingw: forbid translating ERROR_SUCCESS to an errno value
mingw: do set `errno` correctly when trying to restrict handle inheritance
mingw: restrict file handle inheritance only on Windows 7 and later
mingw: spawned processes need to inherit only standard handles
mingw: work around incorrect standard handles
mingw: demonstrate that all file handles are inherited by child processes
|
|
|
Junio C Hamano
Jeff King
Orgad Shaneh
Jeff Hostetler
Johannes Schindelin
Carlo Marcelo Arenas Belón
Đoàn Trần Công Danh
Emily Shaffer
Nathan Sanders
Matthias Aßhauer
Andras Kucsma
Alexandr Miloslavskiy
René Scharfe