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12 daysMerge branch 'rs/xmkstemp-simplify'Junio C Hamano1-18/+1
Code simplification. * rs/xmkstemp-simplify: wrapper: simplify xmkstemp()
2025-11-17wrapper: simplify xmkstemp()René Scharfe1-18/+1
Call xmkstemp_mode() instead of duplicating its error handling code. This switches the implementation from the system's mkstemp(3) to our own git_mkstemp_mode(), which works just as well. Signed-off-by: René Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-10-07config: values of pathname type can be prefixed with :(optional)Junio C Hamano1-0/+13
Sometimes people want to specify additional configuration data as "best effort" basis. Maybe commit.template configuration file points at somewhere in ~/template/ but on a particular system, the file may not exist and the user may be OK without using the template in such a case. When the value given to a configuration variable whose type is pathname wants to signal such an optional file, it can be marked by prepending ":(optional)" in front of it. Such a setting that is marked optional would avoid getting the command barf for a missing file, as an optional configuration setting that names a missing file is not even seen. cf. <xmqq5ywehb69.fsf@gitster.g> Signed-off-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: D. Ben Knoble <ben.knoble+github@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-05-15Merge branch 'cf/wrapper-bsd-eloop'Junio C Hamano1-1/+20
The fallback implementation of open_nofollow() depended on open("symlink", O_NOFOLLOW) to set errno to ELOOP, but a few BSD derived systems use different errno, which has been worked around. * cf/wrapper-bsd-eloop: wrapper: NetBSD gives EFTYPE and FreeBSD gives EMFILE where POSIX uses ELOOP
2025-05-06wrapper: NetBSD gives EFTYPE and FreeBSD gives EMFILE where POSIX uses ELOOPCollin Funk1-1/+20
As documented on NetBSD's man page, open with the O_NOFOLLOW flag and a symlink returns -1 and sets errno to EFTYPE which differs from POSIX. This patch fixes the following test failure: $ sh t0602-reffiles-fsck.sh --verbose --- expect 2025-05-02 23:05:23.920890147 +0000 +++ err 2025-05-02 23:05:23.916794959 +0000 @@ -1 +1 @@ -error: packed-refs: badRefFiletype: not a regular file but a symlink +error: unable to open '.git/packed-refs': Inappropriate file type or format not ok 12 - the filetype of packed-refs should be checked FreeBSD has the same issue for EMLINK instead of EFTYPE. This portability issue was introduced in cfea2f2da8 (packed-backend: check whether the "packed-refs" is regular file, 2025-02-28) Signed-off-by: Collin Funk <collin.funk1@gmail.com> Acked-by: brian m. carlson <sandals@crustytoothpaste.net> Acked-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-15object-file: move `xmmap()` into "wrapper.c"Patrick Steinhardt1-0/+48
The `xmmap()` function is provided by "object-file.c" even though its functionality has nothing to do with the object file subsystem. Move it into "wrapper.c", whose header already declares those functions. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-07wrapper: allow generating insecure random bytesPatrick Steinhardt1-10/+14
The `csprng_bytes()` function generates randomness and writes it into a caller-provided buffer. It abstracts over a couple of implementations, where the exact one that is used depends on the platform. These implementations have different guarantees: while some guarantee to never fail (arc4random(3)), others may fail. There are two significant failures to distinguish from one another: - Systemic failure, where e.g. opening "/dev/urandom" fails or when OpenSSL doesn't have a provider configured. - Entropy failure, where the entropy pool is exhausted, and thus the function cannot guarantee strong cryptographic randomness. While we cannot do anything about the former, the latter failure can be acceptable in some situations where we don't care whether or not the randomness can be predicted. Introduce a new `CSPRNG_BYTES_INSECURE` flag that allows callers to opt into weak cryptographic randomness. The exact behaviour of the flag depends on the underlying implementation: - `arc4random_buf()` never returns an error, so it doesn't change. - `getrandom()` pulls from "/dev/urandom" by default, which never blocks on modern systems even when the entropy pool is empty. - `getentropy()` seems to block when there is not enough randomness available, and there is no way of changing that behaviour. - `GtlGenRandom()` doesn't mention anything about its specific failure mode. - The fallback reads from "/dev/urandom", which also returns bytes in case the entropy pool is drained in modern Linux systems. That only leaves OpenSSL with `RAND_bytes()`, which returns an error in case the returned data wouldn't be cryptographically safe. This function is replaced with a call to `RAND_pseudo_bytes()`, which can indicate whether or not the returned data is cryptographically secure via its return value. If it is insecure, and if the `CSPRNG_BYTES_INSECURE` flag is set, then we ignore the insecurity and return the data regardless. It is somewhat questionable whether we really need the flag in the first place, or whether we wouldn't just ignore the potentially-insecure data. But the risk of doing that is that we might have or grow callsites that aren't aware of the potential insecureness of the data in places where it really matters. So using a flag to opt-in to that behaviour feels like the more secure choice. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-06global: mark code units that generate warnings with `-Wsign-compare`Patrick Steinhardt1-0/+3
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>
2024-04-21don't report vsnprintf(3) error as bugRené Scharfe1-1/+1
strbuf_addf() has been reporting a negative return value of vsnprintf(3) as a bug since f141bd804d (Handle broken vsnprintf implementations in strbuf, 2007-11-13). Other functions copied that behavior: 7b03c89ebd (add xsnprintf helper function, 2015-09-24) 5ef264dbdb (strbuf.c: add `strbuf_insertf()` and `strbuf_vinsertf()`, 2019-02-25) 8d25663d70 (mem-pool: add mem_pool_strfmt(), 2024-02-25) However, vsnprintf(3) can legitimately return a negative value if the formatted output would be longer than INT_MAX. Stop accusing it of being broken and just report the fact that formatting failed. 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>
2023-12-26treewide: remove unnecessary includes in source filesElijah Newren1-1/+0
Each of these were checked with gcc -E -I. ${SOURCE_FILE} | grep ${HEADER_FILE} to ensure that removing the direct inclusion of the header actually resulted in that header no longer being included at all (i.e. that no other header pulled it in transitively). ...except for a few cases where we verified that although the header was brought in transitively, nothing from it was directly used in that source file. These cases were: * builtin/credential-cache.c * builtin/pull.c * builtin/send-pack.c Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-09-29parse: separate out parsing functions from config.hCalvin Wan1-1/+1
The files config.{h,c} contain functions that have to do with parsing, but not config. In order to further reduce all-in-one headers, separate out functions in config.c that do not operate on config into its own file, parse.h, and update the include directives in the .c files that need only such functions accordingly. Signed-off-by: Calvin Wan <calvinwan@google.com> Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-09-29wrapper: reduce scope of remove_or_warn()Calvin Wan1-6/+0
remove_or_warn() is only used by entry.c and apply.c, but it is currently declared and defined in wrapper.{h,c}, so it has a scope much greater than it needs. This needlessly large scope also causes wrapper.c to need to include object.h, when this file is largely unconcerned with Git objects. Move remove_or_warn() to entry.{h,c}. The file apply.c still has access to it, since it already includes entry.h for another reason. Signed-off-by: Calvin Wan <calvinwan@google.com> Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-08-10maintenance: add get_random_minute()Derrick Stolee1-0/+10
When we initially created background maintenance -- with its hourly, daily, and weekly schedules -- we considered the effects of all clients launching fetches to the server every hour on the hour. The worry of DDoSing server hosts was noted, but left as something we would consider for a future update. As background maintenance has gained more adoption over the past three years, our worries about DDoSing the big Git hosts has been unfounded. Those systems, especially those serving public repositories, are already resilient to thundering herds of much smaller scale. However, sometimes organizations spin up specific custom server infrastructure either in addition to or on top of their Git host. Some of these technologies are built for a different range of scale, and can hit concurrency limits sooner. Organizations with such custom infrastructures are more likely to recommend tools like `scalar` which furthers their adoption of background maintenance. To help solve for this, create get_random_minute() as a method to help Git select a random minute when creating schedules in the future. The integrations with this method do not yet exist, but will follow in future changes. To avoid multiple sources of randomness in the Git codebase, create a new helper function, git_rand(), that returns a random uint32_t. This is similar to how rand() returns a random nonnegative value, except it is based on csprng_bytes() which is cryptographic and will return values larger than RAND_MAX. One thing that is important for testability is that we notice when we are under a test scenario and return a predictable result. The schedules themselves are not checked for this value, but at least one launchctl test checks that we do not unnecessarily reboot the schedule if it has not changed from a previous version. Signed-off-by: Derrick Stolee <derrickstolee@github.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-08-02Merge branch 'bb/use-trace2-counters-for-fsync-stats'Junio C Hamano1-17/+2
Instead of inventing a custom counter variables for debugging, use existing trace2 facility in the fsync customization codepath. * bb/use-trace2-counters-for-fsync-stats: wrapper: use trace2 counters to collect fsync stats
2023-07-25Merge branch 'mh/mingw-case-sensitive-build'Junio C Hamano1-1/+1
Names of MinGW header files are spelled in mixed case in some source files, but the build host can be using case sensitive filesystem with header files with their name spelled in all lowercase. * mh/mingw-case-sensitive-build: mingw: use lowercase includes for some Windows headers
2023-07-20wrapper: use trace2 counters to collect fsync statsBeat Bolli1-17/+2
As mentioned in the thread starting at [1], trace2 counters should be used to count events instead of ad-hoc static variables. Convert the two fsync static variables to trace2 counters, reducing the coupling between wrapper.c and the trace2 subsystem. Adjust t/t5351 to match the trace2 counter output format. The counters are not per-thread because the ones being replaced also were not. [1] https://lore.kernel.org/git/20230627195251.1973421-2-calvinwan@google.com/ Signed-off-by: Beat Bolli <dev+git@drbeat.li> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-07-05treewide: remove unnecessary includes for wrapper.hCalvin Wan1-1/+0
Signed-off-by: Calvin Wan <calvinwan@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-06-12mingw: use lowercase includes for some Windows headersMike Hommey1-1/+1
When cross-compiling with the mingw toolchain on a system with a case sensitive filesystem, the mixed case (which is technically correct as per the contents of MS Visual C++) doesn't work (the corresponding mingw headers are all lowercase for some reason). Signed-off-by: Mike Hommey <mh@glandium.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-04-24treewide: remove cache.h inclusion due to previous changesElijah Newren1-1/+2
Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-04-24hash-ll.h: split out of hash.h to remove dependency on repository.hElijah Newren1-0/+1
hash.h depends upon and includes repository.h, due to the definition and use of the_hash_algo (defined as the_repository->hash_algo). However, most headers trying to include hash.h are only interested in the layout of the structs like object_id. Move the parts of hash.h that do not depend upon repository.h into a new file hash-ll.h (the "low level" parts of hash.h), and adjust other files to use this new header where the convenience inline functions aren't needed. This allows hash.h and object.h to be fairly small, minimal headers. It also exposes a lot of hidden dependencies on both path.h (which was brought in by repository.h) and repository.h (which was previously implicitly brought in by object.h), so also adjust other files to be more explicit about what they depend upon. Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-04-24treewide: be explicit about dependence on strbuf.hElijah Newren1-0/+1
Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-04-11treewide: be explicit about dependence on trace.h & trace2.hElijah Newren1-0/+1
Dozens of files made use of trace and trace2 functions, without explicitly including trace.h or trace2.h. This made it more difficult to find which files could remove a dependence on cache.h. Make C files explicitly include trace.h or trace2.h if they are using them. Signed-off-by: Elijah Newren <newren@gmail.com> Acked-by: Calvin Wan <calvinwan@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-03-21wrapper.h: move declarations for wrapper.c functions from cache.hElijah Newren1-0/+1
Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-03-21abspath.h: move absolute path functions from cache.hElijah Newren1-0/+1
This is another step towards letting us remove the include of cache.h in strbuf.c. It does mean that we also need to add includes of abspath.h in a number of C files. Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-03-21treewide: be explicit about dependence on gettext.hElijah Newren1-0/+1
Dozens of files made use of gettext functions, without explicitly including gettext.h. This made it more difficult to find which files could remove a dependence on cache.h. Make C files explicitly include gettext.h if they are using it. However, while compat/fsmonitor/fsm-ipc-darwin.c should also gain an include of gettext.h, it was left out to avoid conflicting with an in-flight topic. Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-25Merge branch 'jk/pipe-command-nonblock'Junio C Hamano1-22/+0
Fix deadlocks between main Git process and subprocess spawned via the pipe_command() API, that can kill "git add -p" that was reimplemented in C recently. * jk/pipe-command-nonblock: pipe_command(): mark stdin descriptor as non-blocking pipe_command(): handle ENOSPC when writing to a pipe pipe_command(): avoid xwrite() for writing to pipe git-compat-util: make MAX_IO_SIZE define globally available nonblock: support Windows compat: add function to enable nonblocking pipes
2022-08-17git-compat-util: make MAX_IO_SIZE define globally availableJeff King1-22/+0
We define MAX_IO_SIZE within wrapper.c, but it's useful for any code that wants to do a raw write() for whatever reason (say, because they want different EAGAIN handling). Let's make it available everywhere. The alternative would be adding xwrite_foo() variants to give callers more options. But there's really no reason MAX_IO_SIZE needs to be abstracted away, so this give callers the most flexibility. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-07-18trace2: only include "fsync" events if we git_fsync()Ævar Arnfjörð Bjarmason1-2/+8
Fix the overly verbose trace2 logging added in 9a4987677d3 (trace2: add stats for fsync operations, 2022-03-30) (first released with v2.36.0). Since that change every single "git" command invocation has included these "data" events, even though we'll only make use of these with core.fsyncMethod=batch, and even then only have non-zero values if we're writing object data to disk. See c0f4752ed2f (core.fsyncmethod: batched disk flushes for loose-objects, 2022-04-04) for that feature. As we're needing to indent the trace2_data_intmax() lines let's introduce helper variables to ensure that our resulting lines (which were already too) don't exceed the recommendations of the CodingGuidelines. Doing that requires either wrapping them twice, or introducing short throwaway variable names, let's do the latter. The result was that e.g. "git version" would previously emit a total of 6 trace2 events with the GIT_TRACE2_EVENT target (version, start, cmd_ancestry, cmd_name, exit, atexit), but afterwards would emit 8. We'd emit 2 "data" events before the "exit" event. The reason we didn't catch this was that the trace2 unit tests added in a15860dca3f (trace2: t/helper/test-trace2, t0210.sh, t0211.sh, t0212.sh, 2019-02-22) would omit any "data" events that weren't the ones it cared about. Before this change to the C code 6/7 of our "t/t0212-trace2-event.sh" tests would fail if this change was applied to "t/t0212/parse_events.perl". Let's make the trace2 testing more strict, and further append any new events types we don't know about in "t/t0212/parse_events.perl". Since we only invoke the "test-tool trace2" there's no guarantee that we'll catch other overly verbose events in the future, but we'll at least notice if we start emitting new events that are issues every time we log anything with trace2's JSON target. We exclude the "data_json" event type, we'd otherwise would fail on both "win test" and "win+VS test" CI due to the logging added in 353d3d77f4f (trace2: collect Windows-specific process information, 2019-02-22). It looks like that logging should really be using trace2_cmd_ancestry() instead, which was introduced later in 2f732bf15e6 (tr2: log parent process name, 2021-07-21), but let's leave it for now. The fix-up to aaf81223f48 (unpack-objects: use stream_loose_object() to unpack large objects, 2022-06-11) is needed because we're changing the behavior of these events as discussed above. Since we'd always emit a "hardware-flush" event the test added in aaf81223f48 wasn't testing anything except that this trace2 data was unconditionally logged. Even if "core.fsyncMethod" wasn't set to "batch" we'd pass the test. Now we'll check the expected number of "writeout" v.s. "flush" calls under "core.fsyncMethod=batch", but note that this doesn't actually test if we carried out the sync using that method, on a platform where we'd have to fall back to fsync() each of those "writeout" would really be a "flush" (i.e. a full fsync()). But in this case what we're testing is that the logic in "unpack-objects" behaves as expected, not the OS-specific question of whether we actually were able to use the "bulk" method. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-20Merge branch 'ep/maint-equals-null-cocci'Junio C Hamano1-1/+1
Introduce and apply coccinelle rule to discourage an explicit comparison between a pointer and NULL, and applies the clean-up to the maintenance track. * ep/maint-equals-null-cocci: tree-wide: apply equals-null.cocci tree-wide: apply equals-null.cocci contrib/coccinnelle: add equals-null.cocci
2022-05-02tree-wide: apply equals-null.cocciJunio C Hamano1-1/+1
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-03-30trace2: add stats for fsync operationsNeeraj Singh1-0/+12
Add some global trace2 statistics for the number of fsyncs performed during the lifetime of a Git process. These stats are printed as part of trace2_cmd_exit_fl, which is presumably where we might want to print any other cross-cutting statistics. Signed-off-by: Neeraj Singh <neerajsi@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-03-10core.fsyncmethod: add writeout-only modeNeeraj Singh1-0/+64
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>
2022-03-10wrapper: make inclusion of Windows csprng header tightly scopedNeeraj Singh1-0/+7
Including NTSecAPI.h in git-compat-util.h causes build errors in any other file that includes winternl.h. NTSecAPI.h was included in order to get access to the RtlGenRandom cryptographically secure PRNG. This change scopes the inclusion of ntsecapi.h to wrapper.c, which is the only place that it's actually needed. The build breakage is due to the definition of UNICODE_STRING in NtSecApi.h: #ifndef _NTDEF_ typedef LSA_UNICODE_STRING UNICODE_STRING, *PUNICODE_STRING; typedef LSA_STRING STRING, *PSTRING ; #endif LsaLookup.h: typedef struct _LSA_UNICODE_STRING { USHORT Length; USHORT MaximumLength; #ifdef MIDL_PASS [size_is(MaximumLength/2), length_is(Length/2)] #endif // MIDL_PASS PWSTR Buffer; } LSA_UNICODE_STRING, *PLSA_UNICODE_STRING; winternl.h also defines UNICODE_STRING: typedef struct _UNICODE_STRING { USHORT Length; USHORT MaximumLength; PWSTR Buffer; } UNICODE_STRING; typedef UNICODE_STRING *PUNICODE_STRING; Both definitions have equivalent layouts. Apparently these internal Windows headers aren't designed to be included together. This is an oversight in the headers and does not represent an incompatibility between the APIs. Signed-off-by: Neeraj Singh <neerajsi@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-01-17wrapper: use a CSPRNG to generate random file namesbrian m. carlson1-11/+4
The current way we generate random file names is by taking the seconds and microseconds, plus the PID, and mixing them together, then encoding them. If this fails, we increment the value by 7777, and try again up to TMP_MAX times. Unfortunately, this is not the best idea from a security perspective. If we're writing into TMPDIR, an attacker can guess these values easily and prevent us from creating any temporary files at all by creating them all first. Even though we set TMP_MAX to 16384, this may be achievable in some contexts, even if unlikely to occur in practice. Fortunately, we can simply solve this by using the system cryptographically secure pseudorandom number generator (CSPRNG) to generate a random 64-bit value, and use that as before. Note that there is still a small bias here, but because a six-character sequence chosen out of 62 characters provides about 36 bits of entropy, the bias here is less than 2^-28, which is acceptable, especially considering we'll retry several times. Note that the use of a CSPRNG in generating temporary file names is also used in many libcs. glibc recently changed from an approach similar to ours to using a CSPRNG, and FreeBSD and OpenBSD also use a CSPRNG in this case. Even if the likelihood of an attack is low, we should still be at least as responsible in creating temporary files as libc is. Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-01-17wrapper: add a helper to generate numbers from a CSPRNGbrian m. carlson1-0/+66
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>
2021-10-29wrapper: remove xunsetenv()Carlo Marcelo Arenas Belón1-6/+0
Remove the unused wrapper function. Reported-by: Randall S. Becker <rsbecker@nexbridge.com> Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-22wrapper.c: add x{un,}setenv(), and use xsetenv() in environment.cÆvar Arnfjörð Bjarmason1-0/+12
Add fatal wrappers for setenv() and unsetenv(). In d7ac12b25d3 (Add set_git_dir() function, 2007-08-01) we started checking its return value, and since 48988c4d0c3 (set_git_dir: die when setenv() fails, 2018-03-30) we've had set_git_dir_1() die if we couldn't set it. Let's provide a wrapper for both, this will be useful in many other places, a subsequent patch will make another use of xsetenv(). The checking of the return value here is over-eager according to setenv(3) and POSIX. It's documented as returning just -1 or 0, so perhaps we should be checking -1 explicitly. Let's just instead die on any non-zero, if our C library is so broken as to return something else than -1 on error (and perhaps not set errno?) the worst we'll do is die with a nonsensical errno value, but we'll want to die in either case. Let's make these return "void" instead of "int". As far as I can tell there's no other x*() wrappers that needed to make the decision of deviating from the signature in the C library, but since their return value is only used to indicate errors (so we'd die here), we can catch unreachable code such as if (xsetenv(...) < 0) [...]; I think it would be OK skip the NULL check of the "name" here for the calls to die_errno(). Almost all of our setenv() callers are taking a constant string hardcoded in the source as the first argument, and for the rest we can probably assume they've done the NULL check themselves. Even if they didn't, modern C libraries are forgiving about it (e.g. glibc formatting it as "(null)"), on those that aren't, well, we were about to die anyway. But let's include the check anyway for good measure. 1. https://pubs.opengroup.org/onlinepubs/009604499/functions/setenv.html Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-25xopen: explicitly report creation failuresRené Scharfe1-1/+3
If the flags O_CREAT and O_EXCL are both given then open(2) is supposed to create the file and error out if it already exists. The error message in that case looks like this: fatal: could not open 'foo' for writing: File exists Without further context this is confusing: Why should the existence of the file pose a problem? Isn't that a requirement for writing to it? Add a more specific error message for that case to tell the user that we actually don't expect the file to preexist, so the example becomes: fatal: unable to create 'foo': File exists Signed-off-by: René Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-16add open_nofollow() helperJeff King1-0/+16
Some callers of open() would like to use O_NOFOLLOW, but it is not available on all platforms. Let's abstract this into a helper function so we can provide system-specific implementations. Some light web-searching reveals that we might be able to get something similar on Windows using FILE_FLAG_OPEN_REPARSE_POINT. I didn't dig into this further. For other systems without O_NOFOLLOW or any equivalent, we have two options for fallback: - we can just open anyway, following symlinks; this may have security implications (e.g., following untrusted in-tree symlinks) - we can determine whether the path is a symlink with lstat(). This is slower (two syscalls instead of one), but that may be acceptable for infrequent uses like looking up .gitattributes files (especially because we can get away with a single syscall for the common case of ENOENT). It's also racy, but should be sufficient for our needs (we are worried about in-tree symlinks that we ourselves would have previously created). We could make it non-racy at the cost of making it even slower, by doing an fstat() on the opened descriptor and comparing the dev/ino fields to the original lstat(). This patch implements the lstat() option in its slightly-faster racy form. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-02xrealloc: do not reuse pointer freed by zero-length realloc()Jeff King1-2/+5
This patch fixes a bug where xrealloc(ptr, 0) can double-free and corrupt the heap on some platforms (including at least glibc). The C99 standard says of malloc (section 7.20.3): If the size of the space requested is zero, the behavior is implementation-defined: either a null pointer is returned, or the behavior is as if the size were some nonzero value, except that the returned pointer shall not be used to access an object. So we might get NULL back, or we might get an actual pointer (but we're not allowed to look at its contents). To simplify our code, our xmalloc() handles a NULL return by converting it into a single-byte allocation. That way callers get consistent behavior. This was done way back in 4e7a2eccc2 (?alloc: do not return NULL when asked for zero bytes, 2005-12-29). We also gave xcalloc() and xrealloc() the same treatment. And according to C99, that is fine; the text above is in a paragraph that applies to all three. But what happens to the memory we passed to realloc() in such a case? I.e., if we do: ret = realloc(ptr, 0); and "ptr" is non-NULL, but we get NULL back, is "ptr" still valid? C99 doesn't cover this case specifically, but says (section 7.20.3.4): The realloc function deallocates the old object pointed to by ptr and returns a pointer to a new object that has the size specified by size. So "ptr" is now deallocated, and we must only look at "ret". And since "ret" is NULL, that means we have no allocated object at all. But that's not quite the whole story. It also says: If memory for the new object cannot be allocated, the old object is not deallocated and its value is unchanged. [...] The realloc function returns a pointer to the new object (which may have the same value as a pointer to the old object), or a null pointer if the new object could not be allocated. So if we see a NULL return with a non-zero size, we can expect that the original object _is_ still valid. But with a non-zero size, it's ambiguous. The NULL return might mean a failure (in which case the object is valid), or it might mean that we successfully allocated nothing, and used NULL to represent that. The glibc manpage for realloc() explicitly says: [...]if size is equal to zero, and ptr is not NULL, then the call is equivalent to free(ptr). Likewise, this StackOverflow answer: https://stackoverflow.com/a/2135302 claims that C89 gave similar guidance (but I don't have a copy to verify it). A comment on this answer: https://stackoverflow.com/a/2022410 claims that Microsoft's CRT behaves the same. But our current "retry with 1 byte" code passes the original pointer again. So on glibc, we effectively free() the pointer and then try to realloc() it again, which is undefined behavior. The simplest fix here is to just pass "ret" (which we know to be NULL) to the follow-up realloc(). But that means that a system which _doesn't_ free the original pointer would leak it. It's not clear if any such systems exist, and that interpretation of the standard seems unlikely (I'd expect a system that doesn't deallocate to simply return the original pointer in this case). But it's easy enough to err on the safe side, and just never pass a zero size to realloc() at all. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-27wrapper: add function to compare strings with different NUL terminationbrian m. carlson1-0/+8
When parsing capabilities for the pack protocol, there are times we'll want to compare the value of a capability to a NUL-terminated string. Since the data we're reading will be space-terminated, not NUL-terminated, we need a function that compares the two strings, but also checks that they're the same length. Otherwise, if we used strncmp to compare these strings, we might accidentally accept a parameter that was a prefix of the expected value. Add a function, xstrncmpz, that takes a NUL-terminated string and a non-NUL-terminated string, plus a length, and compares them, ensuring that they are the same length. Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-22Merge branch 'dl/wrapper-fix-indentation'Junio C Hamano1-2/+2
Coding style fix. * dl/wrapper-fix-indentation: wrapper: indent with tabs
2020-03-28wrapper: indent with tabsDenton Liu1-2/+2
The codebase uses tabs for indentation. Convert an erroneous space indent into a tab indent. Signed-off-by: Denton Liu <liu.denton@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-09Merge branch 'ah/cleanups'Junio C Hamano1-10/+11
Miscellaneous code clean-ups. * ah/cleanups: git_mkstemps_mode(): replace magic numbers with computed value wrapper: use a loop instead of repetitive statements diffcore-break: use a goto instead of a redundant if statement commit-graph: remove a duplicate assignment
2019-10-03git_mkstemps_mode(): replace magic numbers with computed valueJeff King1-5/+7
The magic number "6" appears several times in the function, and is related to the size of the "XXXXXX" string we expect to find in the template. Let's pull that "XXXXXX" into a constant array, whose size we can get at compile time with ARRAY_SIZE(). Note that we probably can't just change this value, since callers will be feeding us a certain number of X's, but it hopefully makes the function itself easier to follow. While we're here, let's do the same with the "letters" array (which we _could_ modify if we wanted to include more characters). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-02wrapper: use a loop instead of repetitive statementsAlex Henrie1-6/+5
A check into the history of this code revealed no particular reason for the code to be written in this way. All popular compilers are capable of unrolling loops if it benefits performance, and once this code is replaced with a loop, the magic number 6 used in multiple places in this function can be replaced with a named constant. Reviewed-by: Derrick Stolee <stolee@gmail.com> Reviewed-by: Johannes Schindelin <Johannes.Schindelin@gmx.de> Reviewed-by: Jeff King <peff@peff.net> Signed-off-by: Alex Henrie <alexhenrie24@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-08-13packfile: drop release_pack_memory()Jeff King1-50/+13
Long ago, in 97bfeb34df (Release pack windows before reporting out of memory., 2006-12-24), we taught xmalloc() and friends to try unmapping pack windows when malloc() failed. It's unlikely that his helps a lot in practice, and it has some downsides. First, the downsides: 1. It makes xmalloc() not thread-safe. We've worked around this in pack-objects.c, which installs its own locking version of the try_to_free_routine(). But other threaded code doesn't. 2. It makes the system as a whole harder to reason about. Functions which allocate heap memory under the hood may have farther-reaching effects than expected. That might be worth the tradeoff if there's a benefit. But in practice, it seems unlikely. We're generally dealing with mmap'd files, so the OS is going to do a much better job at responding to memory pressure by dropping individual pages (the exception is systems with NO_MMAP, but even there the OS can probably respond just as well with swapping). So the only thing we're really freeing is address space. On 64-bit systems, we have plenty of that to go around. On 32-bit systems, it could possibly help. But around the same time we made two other changes: 77ccc5bbd1 (Introduce new config option for mmap limit., 2006-12-23) and 60bb8b1453 (Fully activate the sliding window pack access., 2006-12-23). Together that means that a 32-bit system should have no more than 256MB total of packed-git mmaps at one time, split between a few 32MB windows. It's unlikely we have any address space problems since then, but we don't have any data since the features were all added at the same time. Likewise, xmmap() will try to free memory. At first glance, it seems like we'd need this (when we try to mmap a new window, we might need to close an old one to save address space on a 32-bit system). But we're saved again by core.packedGitLimit: if we're going to exceed our 256MB limit, we'll close an existing window before we even call mmap(). So it seems unlikely that this feature is actually doing anything useful. And while we don't have reports of it harming anything (probably because it rarely if ever kicks in), it would be nice to simplify the system overall. This patch drops the whole try_to_free system from xmalloc(), as well as the manual pack memory release in xmmap(). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-06-19wrapper: avoid undefined behaviour in macOSCarlo Marcelo Arenas Belón1-1/+1
0620b39b3b ("compat: add a mkstemps() compatibility function", 2009-05-31) included a function based on code from libiberty which would result in undefined behaviour in platforms where timeval's tv_usec is a 32-bit signed type as shown by: wrapper.c:505:31: runtime error: left shift of 594546 by 16 places cannot be represented in type '__darwin_suseconds_t' (aka 'int') interestingly the version of this code from gcc never had this bug and the code had a cast that would had prevented the issue (at least in 64-bit platforms) but was misapplied. change the cast to uint64_t so it also works in 32-bit platforms. Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-02wrapper: move is_empty_file() and rename it as is_empty_or_missing_file()Pranit Bauva1-0/+13
is_empty_file() can help to refactor a lot of code. This will be very helpful in porting "git bisect" to C. Suggested-by: Torsten Bögershausen <tboegi@web.de> Mentored-by: Lars Schneider <larsxschneider@gmail.com> Mentored-by: Christian Couder <chriscool@tuxfamily.org> Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-05-06Replace all die("BUG: ...") calls by BUG() onesJohannes Schindelin1-2/+2
In d8193743e08 (usage.c: add BUG() function, 2017-05-12), a new macro was introduced to use for reporting bugs instead of die(). It was then subsequently used to convert one single caller in 588a538ae55 (setup_git_env: convert die("BUG") to BUG(), 2017-05-12). The cover letter of the patch series containing this patch (cf 20170513032414.mfrwabt4hovujde2@sigill.intra.peff.net) is not terribly clear why only one call site was converted, or what the plan is for other, similar calls to die() to report bugs. Let's just convert all remaining ones in one fell swoop. This trick was performed by this invocation: sed -i 's/die("BUG: /BUG("/g' $(git grep -l 'die("BUG' \*.c) Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-02-22wrapper: rename 'template' variablesBrandon Williams1-20/+20
Rename C++ keyword in order to bring the codebase closer to being able to be compiled with a C++ compiler. Signed-off-by: Brandon Williams <bmwill@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-11-06wrapper.c: consistently quote filenames in error messagesSimon Ruderich1-4/+4
All other error messages in the file use quotes around the file name. This change removes two translations as "could not write to '%s'" and "could not close '%s'" are already translated and these two are the only occurrences without quotes. Signed-off-by: Simon Ruderich <simon@ruderich.org> [jc: adjusted tests I noticed were broken by the change] Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-14avoid "write_in_full(fd, buf, len) != len" patternJeff King1-1/+1
The return value of write_in_full() is either "-1", or the requested number of bytes[1]. If we make a partial write before seeing an error, we still return -1, not a partial value. This goes back to f6aa66cb95 (write_in_full: really write in full or return error on disk full., 2007-01-11). So checking anything except "was the return value negative" is pointless. And there are a couple of reasons not to do so: 1. It can do a funny signed/unsigned comparison. If your "len" is signed (e.g., a size_t) then the compiler will promote the "-1" to its unsigned variant. This works out for "!= len" (unless you really were trying to write the maximum size_t bytes), but is a bug if you check "< len" (an example of which was fixed recently in config.c). We should avoid promoting the mental model that you need to check the length at all, so that new sites are not tempted to copy us. 2. Checking for a negative value is shorter to type, especially when the length is an expression. 3. Linus says so. In d34cf19b89 (Clean up write_in_full() users, 2007-01-11), right after the write_in_full() semantics were changed, he wrote: I really wish every "write_in_full()" user would just check against "<0" now, but this fixes the nasty and stupid ones. Appeals to authority aside, this makes it clear that writing it this way does not have an intentional benefit. It's a historical curiosity that we never bothered to clean up (and which was undoubtedly cargo-culted into new sites). So let's convert these obviously-correct cases (this includes write_str_in_full(), which is just a wrapper for write_in_full()). [1] A careful reader may notice there is one way that write_in_full() can return a different value. If we ask write() to write N bytes and get a return value that is _larger_ than N, we could return a larger total. But besides the fact that this would imply a totally broken version of write(), it would already invoke undefined behavior. Our internal remaining counter is an unsigned size_t, which means that subtracting too many byte will wrap it around to a very large number. So we'll instantly begin reading off the end of the buffer, trying to write gigabytes (or petabytes) of data. Signed-off-by: Jeff King <peff@peff.net> Reviewed-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-24Merge branch 'bw/config-h'Junio C Hamano1-0/+1
Fix configuration codepath to pay proper attention to commondir that is used in multi-worktree situation, and isolate config API into its own header file. * bw/config-h: config: don't implicitly use gitdir or commondir config: respect commondir setup: teach discover_git_directory to respect the commondir config: don't include config.h by default config: remove git_config_iter config: create config.h
2017-06-15config: don't include config.h by defaultBrandon Williams1-0/+1
Stop including config.h by default in cache.h. Instead only include config.h in those files which require use of the config system. Signed-off-by: Brandon Williams <bmwill@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-06-13Merge branch 'nd/fopen-errors'Junio C Hamano1-5/+26
We often try to open a file for reading whose existence is optional, and silently ignore errors from open/fopen; report such errors if they are not due to missing files. * nd/fopen-errors: mingw_fopen: report ENOENT for invalid file names mingw: verify that paths are not mistaken for remote nicknames log: fix memory leak in open_next_file() rerere.c: move error_errno() closer to the source system call print errno when reporting a system call error wrapper.c: make warn_on_inaccessible() static wrapper.c: add and use fopen_or_warn() wrapper.c: add and use warn_on_fopen_errors() config.mak.uname: set FREAD_READS_DIRECTORIES for Darwin, too config.mak.uname: set FREAD_READS_DIRECTORIES for Linux and FreeBSD clone: use xfopen() instead of fopen() use xfopen() in more places git_fopen: fix a sparse 'not declared' warning
2017-06-13Merge branch 'jc/noent-notdir'Junio C Hamano1-2/+2
Our code often opens a path to an optional file, to work on its contents when we can successfully open it. We can ignore a failure to open if such an optional file does not exist, but we do want to report a failure in opening for other reasons (e.g. we got an I/O error, or the file is there, but we lack the permission to open). The exact errors we need to ignore are ENOENT (obviously) and ENOTDIR (less obvious). Instead of repeating comparison of errno with these two constants, introduce a helper function to do so. * jc/noent-notdir: treewide: use is_missing_file_error() where ENOENT and ENOTDIR are checked compat-util: is_missing_file_error()
2017-05-30treewide: use is_missing_file_error() where ENOENT and ENOTDIR are checkedJunio C Hamano1-2/+2
Using the is_missing_file_error() helper introduced in the previous step, update all hits from $ git grep -e ENOENT --and -e ENOTDIR There are codepaths that only check ENOENT, and it is possible that some of them should be checking both. Updating them is kept out of this step deliberately, as we do not want to change behaviour in this step. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-26wrapper.c: make warn_on_inaccessible() staticNguyễn Thái Ngọc Duy1-5/+5
After the last patch, this function is not used outside anymore. Keep it static. Noticed-by: Ramsay Jones <ramsay@ramsayjones.plus.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-26wrapper.c: add and use fopen_or_warn()Nguyễn Thái Ngọc Duy1-0/+11
When fopen() returns NULL, it could be because the given path does not exist, but it could also be some other errors and the caller has to check. Add a wrapper so we don't have to repeat the same error check everywhere. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-26wrapper.c: add and use warn_on_fopen_errors()Nguyễn Thái Ngọc Duy1-0/+10
In many places, Git warns about an inaccessible file after a fopen() failed. To discern these cases from other cases where we want to warn about inaccessible files, introduce a new helper specifically to test whether fopen() failed because the current user lacks the permission to open file in question. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-23Merge branch 'dt/xgethostname-nul-termination'Junio C Hamano1-0/+13
gethostname(2) may not NUL terminate the buffer if hostname does not fit; unfortunately there is no easy way to see if our buffer was too small, but at least this will make sure we will not end up using garbage past the end of the buffer. * dt/xgethostname-nul-termination: xgethostname: handle long hostnames use HOST_NAME_MAX to size buffers for gethostname(2)
2017-04-18xgethostname: handle long hostnamesDavid Turner1-0/+13
If the full hostname doesn't fit in the buffer supplied to gethostname, POSIX does not specify whether the buffer will be null-terminated, so to be safe, we should do it ourselves. Introduce new function, xgethostname, which ensures that there is always a \0 at the end of the buffer. Signed-off-by: David Turner <dturner@twosigma.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-02-28wrapper.c: remove unused gitmkstemps() functionRamsay Jones1-7/+0
The last call to the mkstemps() function was removed in commit 659488326 ("wrapper.c: delete dead function git_mkstemps()", 22-04-2016). In order to support platforms without mkstemps(), this functionality was provided, along with a Makefile build variable (NO_MKSTEMPS), by the gitmkstemps() function. Remove the dead code, along with the defunct build machinery. Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-02-28wrapper.c: remove unused git_mkstemp() functionRamsay Jones1-17/+0
The last caller of git_mkstemp() was removed in commit 6fec0a89 ("verify_signed_buffer: use tempfile object", 16-06-2016). Since the introduction of the 'tempfile' APIs, along with git_mkstemp_mode, it is unlikely that new callers will materialize. Remove the dead code. Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com> Reviewed-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-07-19Merge branch 'jk/write-file'Junio C Hamano1-40/+12
General code clean-up around a helper function to write a single-liner to a file. * jk/write-file: branch: use write_file_buf instead of write_file use write_file_buf where applicable write_file: add format attribute write_file: add pointer+len variant write_file: use xopen write_file: drop "gently" form branch: use non-gentle write_file for branch description am: ignore return value of write_file() config: fix bogus fd check when setting up default config
2016-07-19Merge branch 'sb/submodule-parallel-fetch'Junio C Hamano1-16/+27
Fix recently introduced codepaths that are involved in parallel submodule operations, which gave up on reading too early, and could have wasted CPU while attempting to write under a corner case condition. * sb/submodule-parallel-fetch: hoist out handle_nonblock function for xread and xwrite xwrite: poll on non-blocking FDs xread: retry after poll on EAGAIN/EWOULDBLOCK
2016-07-11hoist out handle_nonblock function for xread and xwriteEric Wong1-28/+20
At least for me, this improves the readability of xread and xwrite; hopefully allowing missing "continue" statements to be spotted more easily. Signed-off-by: Eric Wong <e@80x24.org> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-07-08write_file: add pointer+len variantJeff King1-5/+11
There are many callsites which could use write_file, but for which it is a little awkward because they have a strbuf or other pointer/len combo. Specifically: 1. write_file() takes a format string, so we have to use "%s" or "%.*s", which are ugly. 2. Using any form of "%s" does not handle embedded NULs in the output. That probably doesn't matter for our call-sites, but it's nicer not to have to worry. 3. It's less efficient; we format into another strbuf just to do the write. That's probably not measurably slow for our uses, but it's simply inelegant. We can fix this by providing a helper to write out the formatted buffer, and just calling it from write_file(). Note that we don't do the usual "complete with a newline" that write_file does. If the caller has their own buffer, there's a reasonable chance they're doing something more complicated than a single line, and they can call strbuf_complete_line() themselves. We could go even further and add strbuf_write_file(), but it doesn't save much: - write_file_buf(path, sb.buf, sb.len); + strbuf_write_file(&sb, path); It would also be somewhat asymmetric with strbuf_read_file, which actually returns errors rather than dying (and the error handling is most of the benefit of write_file() in the first place). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-07-08write_file: use xopenJeff King1-3/+1
This simplifies the code a tiny bit, and provides consistent error messages with other users of xopen(). While we're here, let's also switch to using O_WRONLY. We know we're only going to open/write/close the file, so there's no point in asking for O_RDWR. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-07-08write_file: drop "gently" formJeff King1-43/+11
There are no callers left of write_file_gently(). Let's drop it, as it doesn't seem likely for new callers to be added (since its inception, the only callers who wanted the gentle form generally just died immediately themselves, and have since been converted). While we're there, let's also drop the "int" return from write_file, as it is never meaningful (in the non-gentle form, we always either die or return 0). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-06-27xwrite: poll on non-blocking FDsEric Wong1-2/+20
write(2) can hit the same EAGAIN/EWOULDBLOCK errors as read(2), so busy-looping on a non-blocking FD is a waste of resources. Currently, I do not know of a way for this happen: * the NonBlocking directive in systemd does not apply to stdin, stdout, or stderr. * xinetd provides no way to set the non-blocking flag at all But theoretically, it's possible a careless C10K HTTP server could use pipe2(..., O_NONBLOCK) to setup a pipe for git-http-backend with only the intent to use non-blocking reads; but accidentally leave non-blocking set on the write end passed as stdout to git-upload-pack. Followup-to: 1079c4be0b720 ("xread: poll on non blocking fds") Signed-off-by: Eric Wong <e@80x24.org> Reviewed-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-06-27xread: retry after poll on EAGAIN/EWOULDBLOCKEric Wong1-0/+1
We should continue to loop after EAGAIN/EWOULDBLOCK as the intent of xread is to try until there is available data, EOF, or an unrecoverable error. Fixes: 1079c4be0b720 ("xread: poll on non blocking fds") Signed-off-by: Eric Wong <e@80x24.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-05-17Merge branch 'nd/error-errno'Junio C Hamano1-2/+2
The code for warning_errno/die_errno has been refactored and a new error_errno() reporting helper is introduced. * nd/error-errno: (41 commits) wrapper.c: use warning_errno() vcs-svn: use error_errno() upload-pack.c: use error_errno() unpack-trees.c: use error_errno() transport-helper.c: use error_errno() sha1_file.c: use {error,die,warning}_errno() server-info.c: use error_errno() sequencer.c: use error_errno() run-command.c: use error_errno() rerere.c: use error_errno() and warning_errno() reachable.c: use error_errno() mailmap.c: use error_errno() ident.c: use warning_errno() http.c: use error_errno() and warning_errno() grep.c: use error_errno() gpg-interface.c: use error_errno() fast-import.c: use error_errno() entry.c: use error_errno() editor.c: use error_errno() diff-no-index.c: use error_errno() ...
2016-05-09wrapper.c: use warning_errno()Nguyễn Thái Ngọc Duy1-2/+2
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-04-22wrapper.c: delete dead function git_mkstemps()Nguyễn Thái Ngọc Duy1-17/+0
Its last call site was replaced by mks_tempfile_ts() in 284098f (diff: use tempfile module - 2015-08-12) and there's a good chance mks_tempfile_ts will continue to successfully handle this job. Delete it. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-02-26Merge branch 'jk/tighten-alloc'Junio C Hamano1-0/+3
Update various codepaths to avoid manually-counted malloc(). * jk/tighten-alloc: (22 commits) ewah: convert to REALLOC_ARRAY, etc convert ewah/bitmap code to use xmalloc diff_populate_gitlink: use a strbuf transport_anonymize_url: use xstrfmt git-compat-util: drop mempcpy compat code sequencer: simplify memory allocation of get_message test-path-utils: fix normalize_path_copy output buffer size fetch-pack: simplify add_sought_entry fast-import: simplify allocation in start_packfile write_untracked_extension: use FLEX_ALLOC helper prepare_{git,shell}_cmd: use argv_array use st_add and st_mult for allocation size computation convert trivial cases to FLEX_ARRAY macros use xmallocz to avoid size arithmetic convert trivial cases to ALLOC_ARRAY convert manual allocations to argv_array argv-array: add detach function add helpers for allocating flex-array structs harden REALLOC_ARRAY and xcalloc against size_t overflow tree-diff: catch integer overflow in combine_diff_path allocation ...
2016-02-22harden REALLOC_ARRAY and xcalloc against size_t overflowJeff King1-0/+3
REALLOC_ARRAY inherently involves a multiplication which can overflow size_t, resulting in a much smaller buffer than we think we've allocated. We can easily harden it by using st_mult() to check for overflow. Likewise, we can add ALLOC_ARRAY to do the same thing for xmalloc calls. xcalloc() should already be fine, because it takes the two factors separately, assuming the system calloc actually checks for overflow. However, before we even hit the system calloc(), we do our memory_limit_check, which involves a multiplication. Let's check for overflow ourselves so that this limit cannot be bypassed. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-02-05Merge branch 'js/fopen-harder' into maintJunio C Hamano1-0/+13
Some codepaths used fopen(3) when opening a fixed path in $GIT_DIR (e.g. COMMIT_EDITMSG) that is meant to be left after the command is done. This however did not work well if the repository is set to be shared with core.sharedRepository and the umask of the previous user is tighter. They have been made to work better by calling unlink(2) and retrying after fopen(3) fails with EPERM. * js/fopen-harder: Handle more file writes correctly in shared repos commit: allow editing the commit message even in shared repos
2016-01-20Merge branch 'js/fopen-harder'Junio C Hamano1-0/+13
Some codepaths used fopen(3) when opening a fixed path in $GIT_DIR (e.g. COMMIT_EDITMSG) that is meant to be left after the command is done. This however did not work well if the repository is set to be shared with core.sharedRepository and the umask of the previous user is tighter. They have been made to work better by calling unlink(2) and retrying after fopen(3) fails with EPERM. * js/fopen-harder: Handle more file writes correctly in shared repos commit: allow editing the commit message even in shared repos
2016-01-12Merge branch 'sb/submodule-parallel-fetch'Junio C Hamano1-2/+18
Add a framework to spawn a group of processes in parallel, and use it to run "git fetch --recurse-submodules" in parallel. Rerolled and this seems to be a lot cleaner. The merge of the earlier one to 'next' has been reverted. * sb/submodule-parallel-fetch: submodules: allow parallel fetching, add tests and documentation fetch_populated_submodules: use new parallel job processing run-command: add an asynchronous parallel child processor sigchain: add command to pop all common signals strbuf: add strbuf_read_once to read without blocking xread: poll on non blocking fds submodule.c: write "Fetching submodule <foo>" to stderr
2016-01-07commit: allow editing the commit message even in shared reposJohannes Schindelin1-0/+13
It was pointed out by Yaroslav Halchenko that the file containing the commit message is writable only by the owner, which means that we have to rewrite it from scratch in a shared repository. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-12-21Merge branch 'jk/ident-loosen-getpwuid'Junio C Hamano1-12/+0
When getpwuid() on the system returned NULL (e.g. the user is not in the /etc/passwd file or other uid-to-name mappings), the codepath to find who the user is to record it in the reflog barfed and died. Loosen the check in this codepath, which already accepts questionable ident string (e.g. host part of the e-mail address is obviously bogus), and in general when we operate fmt_ident() function in non-strict mode. * jk/ident-loosen-getpwuid: ident: loosen getpwuid error in non-strict mode ident: keep a flag for bogus default_email ident: make xgetpwuid_self() a static local helper
2015-12-16xread: poll on non blocking fdsStefan Beller1-2/+18
The man page of read(2) says: EAGAIN The file descriptor fd refers to a file other than a socket and has been marked nonblocking (O_NONBLOCK), and the read would block. EAGAIN or EWOULDBLOCK The file descriptor fd refers to a socket and has been marked nonblocking (O_NONBLOCK), and the read would block. POSIX.1-2001 allows either error to be returned for this case, and does not require these constants to have the same value, so a portable application should check for both possibilities. If we get an EAGAIN or EWOULDBLOCK the fd must have set O_NONBLOCK. As the intent of xread is to read as much as possible either until the fd is EOF or an actual error occurs, we can ease the feeder of the fd by not spinning the whole time, but rather wait for it politely by not busy waiting. We should not care if the call to poll failed, as we're in an infinite loop and can only get out with the correct read(). Signed-off-by: Stefan Beller <sbeller@google.com> Acked-by: Johannes Sixt <j6t@kdbg.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-12-10ident: make xgetpwuid_self() a static local helperJeff King1-12/+0
This function is defined in wrapper.c, but nobody besides ident.c uses it. And nobody is likely to in the future, either, as anything that cares about the user's name should be going through the ident code. Moving it here is a cleanup of the global namespace, but it will also enable further cleanups inside ident.c. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-09-25add xsnprintf helper functionJeff King1-0/+16
There are a number of places in the code where we call sprintf(), with the assumption that the output will fit into the buffer. In many cases this is true (e.g., formatting a number into a large buffer), but it is hard to tell immediately from looking at the code. It would be nice if we had some run-time check to make sure that our assumption is correct (and to communicate to readers of the code that we are not blindly calling sprintf, but have actually thought about this case). This patch introduces xsnprintf, which behaves just like snprintf, except that it dies whenever the output is truncated. This acts as a sort of assert() for these cases, which can help find places where the assumption is violated (as opposed to truncating and proceeding, which may just silently give a wrong answer). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-08-25write_file_v(): do not leave incomplete line at the endJunio C Hamano1-0/+1
All existing callers to this function use it to produce a text file or an empty file, and a new callsite that mimick them must end their payload with a LF. If they forget to do so, the resulting file will end with an incomplete line. Teach write_file_v() to complete the incomplete line, if exists, so that the callers do not have to. With this, the caller-side fix in builtin/am.c becomes unnecessary. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-08-24write_file(): drop "fatal" parameterJunio C Hamano1-4/+24
All callers except three passed 1 for the "fatal" parameter to ask this function to die upon error, but to a casual reader of the code, it was not all obvious what that 1 meant. Instead, split the function into two based on a common write_file_v() that takes the flag, introduce write_file_gently() as a new way to attempt creating a file without dying on error, and make three callers to call it. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-08-04wrapper: implement xfopen()Paul Tan1-0/+21
A common usage pattern of fopen() is to check if it succeeded, and die() if it failed: FILE *fp = fopen(path, "w"); if (!fp) die_errno(_("could not open '%s' for writing"), path); Implement a wrapper function xfopen() for the above, so that we can save a few lines of code and make the die() messages consistent. Helped-by: Jeff King <peff@peff.net> Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de> Helped-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Paul Tan <pyokagan@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-08-04wrapper: implement xopen()Paul Tan1-0/+35
A common usage pattern of open() is to check if it was successful, and die() if it was not: int fd = open(path, O_WRONLY | O_CREAT, 0777); if (fd < 0) die_errno(_("Could not open '%s' for writing."), path); Implement a wrapper function xopen() that does the above so that we can save a few lines of code, and make the die() messages consistent. Helped-by: Torsten Bögershausen <tboegi@web.de> Helped-by: Jeff King <peff@peff.net> Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de> Helped-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Paul Tan <pyokagan@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-06-05help.c: wrap wait-only poll() invocation in sleep_millisec()Johannes Sixt1-0/+5
We want to use the new function elsewhere in a moment. Signed-off-by: Johannes Sixt <j6t@kdbg.org> Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-05-11Merge branch 'nd/multiple-work-trees'Junio C Hamano1-0/+31
A replacement for contrib/workdir/git-new-workdir that does not rely on symbolic links and make sharing of objects and refs safer by making the borrowee and borrowers aware of each other. * nd/multiple-work-trees: (41 commits) prune --worktrees: fix expire vs worktree existence condition t1501: fix test with split index t2026: fix broken &&-chain t2026 needs procondition SANITY git-checkout.txt: a note about multiple checkout support for submodules checkout: add --ignore-other-wortrees checkout: pass whole struct to parse_branchname_arg instead of individual flags git-common-dir: make "modules/" per-working-directory directory checkout: do not fail if target is an empty directory t2025: add a test to make sure grafts is working from a linked checkout checkout: don't require a work tree when checking out into a new one git_path(): keep "info/sparse-checkout" per work-tree count-objects: report unused files in $GIT_DIR/worktrees/... gc: support prune --worktrees gc: factor out gc.pruneexpire parsing code gc: style change -- no SP before closing parenthesis checkout: clean up half-prepared directories in --to mode checkout: reject if the branch is already checked out elsewhere prune: strategies for linked checkouts checkout: support checking out into a new working directory ...
2015-02-25Merge branch 'jc/max-io-size-and-ssize-max'Junio C Hamano1-1/+15
Our default I/O size (8 MiB) for large files was too large for some platforms with smaller SSIZE_MAX, leading to read(2)/write(2) failures. * jc/max-io-size-and-ssize-max: xread/xwrite: clip MAX_IO_SIZE to SSIZE_MAX
2015-02-12xread/xwrite: clip MAX_IO_SIZE to SSIZE_MAXJunio C Hamano1-1/+15
Since 0b6806b9 (xread, xwrite: limit size of IO to 8MB, 2013-08-20), we chomp our calls to read(2) and write(2) into chunks of MAX_IO_SIZE bytes (8 MiB), because a large IO results in a bad latency when the program needs to be killed. This also brought our IO below SSIZE_MAX, which is a limit POSIX allows read(2) and write(2) to fail when the IO size exceeds it, for OS X, where a problem was originally reported. However, there are other systems that define SSIZE_MAX smaller than our default, and feeding 8 MiB to underlying read(2)/write(2) would fail. Make sure we clip our calls to the lower limit as well. Reported-by: Joachim Schmitz <jojo@schmitz-digital.de> Helped-by: Torsten Bögershausen <tboegi@web.de> Helped-by: Eric Sunshine <sunshine@sunshineco.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-12-01wrapper.c: wrapper to open a file, fprintf then closeNguyễn Thái Ngọc Duy1-0/+31
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-15wrapper.c: add a new function unlink_or_msgRonnie Sahlberg1-0/+14
This behaves like unlink_or_warn except that on failure it writes the message to its 'err' argument, which the caller can display in an appropriate way or ignore. Signed-off-by: Ronnie Sahlberg <sahlberg@google.com> Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-15wrapper.c: remove/unlink_or_warn: simplify, treat ENOENT as successRonnie Sahlberg1-8/+6
Simplify the function warn_if_unremovable slightly. Additionally, change behaviour slightly. If we failed to remove the object because the object does not exist, we can still return success back to the caller since none of the callers depend on "fail if the file did not exist". Signed-off-by: Ronnie Sahlberg <sahlberg@google.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-08Merge branch 'sp/stream-clean-filter'Junio C Hamano1-9/+10
When running a required clean filter, we do not have to mmap the original before feeding the filter. Instead, stream the file contents directly to the filter and process its output. * sp/stream-clean-filter: sha1_file: don't convert off_t to size_t too early to avoid potential die() convert: stream from fd to required clean filter to reduce used address space copy_fd(): do not close the input file descriptor mmap_limit: introduce GIT_MMAP_LIMIT to allow testing expected mmap size memory_limit: use git_env_ulong() to parse GIT_ALLOC_LIMIT config.c: add git_env_ulong() to parse environment variable convert: drop arguments other than 'path' from would_convert_to_git()
2014-09-11Merge branch 'nd/large-blobs'Junio C Hamano1-16/+52
Teach a few codepaths to punt (instead of dying) when large blobs that would not fit in core are involved in the operation. * nd/large-blobs: diff: shortcut for diff'ing two binary SHA-1 objects diff --stat: mark any file larger than core.bigfilethreshold binary diff.c: allow to pass more flags to diff_populate_filespec sha1_file.c: do not die failing to malloc in unpack_compressed_entry wrapper.c: introduce gentle xmallocz that does not die()
2014-08-28memory_limit: use git_env_ulong() to parse GIT_ALLOC_LIMITSteffen Prohaska1-7/+8
GIT_ALLOC_LIMIT limits xmalloc()'s size, which is of type size_t. Better use git_env_ulong() to parse the environment variable, so that the postfixes 'k', 'm', and 'g' can be used; and use size_t to store the limit for consistency. The change to size_t has no direct practical impact, because the environment variable is only meant to be used for our own tests, and we use it to test small sizes. The cast of size in the call to die() is changed to uintmax_t to match the format string PRIuMAX. Signed-off-by: Steffen Prohaska <prohaska@zib.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-08-26wrapper: add xgetcwd()René Scharfe1-0/+8
Add the helper function xgetcwd(), which returns the current directory or dies. The returned string has to be free()d after use. Helped-by: Duy Nguyen <pclouds@gmail.com> Signed-off-by: Rene Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-08-18wrapper.c: introduce gentle xmallocz that does not die()Nguyễn Thái Ngọc Duy1-16/+52
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-04-10read-cache.c: verify index file before we opportunistically update itYiannis Marangos1-0/+20
Before we proceed to opportunistically update the index (often done by an otherwise read-only operation like "git status" and "git diff" that internally refreshes the index), we must verify that the current index file is the same as the one that we read earlier before we took the lock on it, in order to avoid a possible race. In the example below git-status does "opportunistic update" and git-rebase updates the index, but the race can happen in general. 1. process A calls git-rebase (or does anything that uses the index) 2. process A applies 1st commit 3. process B calls git-status (or does anything that updates the index) 4. process B reads index 5. process A applies 2nd commit 6. process B takes the lock, then overwrites process A's changes. 7. process A applies 3rd commit As an end result the 3rd commit will have a revert of the 2nd commit. When process B takes the lock, it needs to make sure that the index hasn't changed since step 4. Signed-off-by: Yiannis Marangos <yiannis.marangos@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-04-10wrapper.c: add xpread() similar to xread()Yiannis Marangos1-0/+18
It is a common mistake to call read(2)/pread(2) and forget to anticipate that they may return error with EAGAIN/EINTR when the system call is interrupted. We have xread() helper to relieve callers of read(2) from having to worry about it; add xpread() helper to do the same for pread(2). Update the caller in the builtin/index-pack.c and the mmap emulation in compat/. Signed-off-by: Yiannis Marangos <yiannis.marangos@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-11-12typofixes: fix misspelt commentsMasanari Iida1-1/+1
Signed-off-by: Masanari Iida <standby24x7@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-10-14wrapper.c: only define gitmkstemps if neededRamsay Jones1-0/+2
When the NO_MKSTEMPS build variable is not set, the gitmkstemps function is dead code. Use a preprocessor conditional to only include the definition when needed. Noticed by sparse. ("'gitmkstemps' was not declared. Should it be static?") Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
2013-08-20xread, xwrite: limit size of IO to 8MBSteffen Prohaska1-0/+12
Checking out 2GB or more through an external filter (see test) fails on Mac OS X 10.8.4 (12E55) for a 64-bit executable with: error: read from external filter cat failed error: cannot feed the input to external filter cat error: cat died of signal 13 error: external filter cat failed 141 error: external filter cat failed The reason is that read() immediately returns with EINVAL when asked to read more than 2GB. According to POSIX [1], if the value of nbyte passed to read() is greater than SSIZE_MAX, the result is implementation-defined. The write function has the same restriction [2]. Since OS X still supports running 32-bit executables, the 32-bit limit (SSIZE_MAX = INT_MAX = 2GB - 1) seems to be also imposed on 64-bit executables under certain conditions. For write, the problem has been addressed earlier [6c642a]. Address the problem for read() and write() differently, by limiting size of IO chunks unconditionally on all platforms in xread() and xwrite(). Large chunks only cause problems, like causing latencies when killing the process, even if OS X was not buggy. Doing IO in reasonably sized smaller chunks should have no negative impact on performance. The compat wrapper clipped_write() introduced earlier [6c642a] is not needed anymore. It will be reverted in a separate commit. The new test catches read and write problems. Note that 'git add' exits with 0 even if it prints filtering errors to stderr. The test, therefore, checks stderr. 'git add' should probably be changed (sometime in another commit) to exit with nonzero if filtering fails. The test could then be changed to use test_must_fail. Thanks to the following people for suggestions and testing: Johannes Sixt <j6t@kdbg.org> John Keeping <john@keeping.me.uk> Jonathan Nieder <jrnieder@gmail.com> Kyle J. McKay <mackyle@gmail.com> Linus Torvalds <torvalds@linux-foundation.org> Torsten Bögershausen <tboegi@web.de> [1] http://pubs.opengroup.org/onlinepubs/009695399/functions/read.html [2] http://pubs.opengroup.org/onlinepubs/009695399/functions/write.html [6c642a] commit 6c642a878688adf46b226903858b53e2d31ac5c3 compate/clipped-write.c: large write(2) fails on Mac OS X/XNU Signed-off-by: Steffen Prohaska <prohaska@zib.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-07-22Merge branch 'tr/fd-gotcha-fixes'Junio C Hamano1-1/+1
Two places we did not check return value (expected to be a file descriptor) correctly. * tr/fd-gotcha-fixes: run-command: dup_devnull(): guard against syscalls failing git_mkstemps: correctly test return value of open()
2013-07-12git_mkstemps: correctly test return value of open()Dale R. Worley1-1/+1
open() returns -1 on failure, and indeed 0 is a possible success value if the user closed stdin in our process. Fix the test. Signed-off-by: Thomas Rast <trast@inf.ethz.ch> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-04-15config: allow inaccessible configuration under $HOMEJonathan Nieder1-4/+10
The changes v1.7.12.1~2^2~4 (config: warn on inaccessible files, 2012-08-21) and v1.8.1.1~22^2~2 (config: treat user and xdg config permission problems as errors, 2012-10-13) were intended to prevent important configuration (think "[transfer] fsckobjects") from being ignored when the configuration is unintentionally unreadable (for example with EIO on a flaky filesystem, or with ENOMEM due to a DoS attack). Usually ~/.gitconfig and ~/.config/git are readable by the current user, and if they aren't then it would be easy to fix those permissions, so the damage from adding this check should have been minimal. Unfortunately the access() check often trips when git is being run as a server. A daemon (such as inetd or git-daemon) starts as "root", creates a listening socket, and then drops privileges, meaning that when git commands are invoked they cannot access $HOME and die with fatal: unable to access '/root/.config/git/config': Permission denied Any patch to fix this would have one of three problems: 1. We annoy sysadmins who need to take an extra step to handle HOME when dropping privileges (the current behavior, or any other proposal that they have to opt into). 2. We annoy sysadmins who want to set HOME when dropping privileges, either by making what they want to do impossible, or making them set an extra variable or option to accomplish what used to work (e.g., a patch to git-daemon to set HOME when --user is passed). 3. We loosen the check, so some cases which might be noteworthy are not caught. This patch is of type (3). Treat user and xdg configuration that are inaccessible due to permissions (EACCES) as though no user configuration was provided at all. An alternative method would be to check if $HOME is readable, but that would not help in cases where the user who dropped privileges had a globally readable HOME with only .config or .gitconfig being private. This does not change the behavior when /etc/gitconfig or .git/config is unreadable (since those are more serious configuration errors), nor when ~/.gitconfig or ~/.config/git is unreadable due to problems other than permissions. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Improved-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-01-11Merge branch 'jn/warn-on-inaccessible-loosen' into maintJunio C Hamano1-1/+9
When attempting to read the XDG-style $HOME/.config/git/config and finding that $HOME/.config/git is a file, we gave a wrong error message, instead of treating the case as "a custom config file does not exist there" and moving on. * jn/warn-on-inaccessible-loosen: config: exit on error accessing any config file doc: advertise GIT_CONFIG_NOSYSTEM config: treat user and xdg config permission problems as errors config, gitignore: failure to access with ENOTDIR is ok
2013-01-06Merge branch 'jn/warn-on-inaccessible-loosen'Junio C Hamano1-1/+9
Deal with a situation where .config/git is a file and we notice .config/git/config is not readable due to ENOTDIR, not ENOENT. * jn/warn-on-inaccessible-loosen: config: exit on error accessing any config file doc: advertise GIT_CONFIG_NOSYSTEM config: treat user and xdg config permission problems as errors config, gitignore: failure to access with ENOTDIR is ok
2012-12-18xmkstemp(): avoid showing truncated template more carefullyJunio C Hamano1-1/+1
Some implementations of xmkstemp() leaves the given in/out buffer truncated when they return with failure. 6cf6bb3 (Improve error messages when temporary file creation fails, 2010-12-18) attempted to show the real filename we tried to create (but failed), and if that is not available due to such truncation, to show the original template that was given by the caller. But it failed to take into account that the given template could have "directory/" in front, in which case the truncation point may not be template[0] but somewhere else. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-10-13config: treat user and xdg config permission problems as errorsJonathan Nieder1-0/+8
Git reads multiple configuration files: settings come first from the system config file (typically /etc/gitconfig), then the xdg config file (typically ~/.config/git/config), then the user's dotfile (~/.gitconfig), then the repository configuration (.git/config). Git has always used access(2) to decide whether to use each file; as an unfortunate side effect, that means that if one of these files is unreadable (e.g., EPERM or EIO), git skips it. So if I use ~/.gitconfig to override some settings but make a mistake and give it the wrong permissions then I am subject to the settings the sysadmin chose for /etc/gitconfig. Better to error out and ask the user to correct the problem. This only affects the user and xdg config files, since the user presumably has enough access to fix their permissions. If the system config file is unreadable, the best we can do is to warn about it so the user knows to notify someone and get on with work in the meantime. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-10-13config, gitignore: failure to access with ENOTDIR is okJonathan Nieder1-1/+1
The access_or_warn() function is used to check for optional configuration files like .gitconfig and .gitignore and warn when they are not accessible due to a configuration issue (e.g., bad permissions). It is not supposed to complain when a file is simply missing. Noticed on a system where ~/.config/git was a file --- when the new XDG_CONFIG_HOME support looks for ~/.config/git/config it should ignore ~/.config/git instead of printing irritating warnings: $ git status -s warning: unable to access '/home/jrn/.config/git/config': Not a directory warning: unable to access '/home/jrn/.config/git/config': Not a directory warning: unable to access '/home/jrn/.config/git/config': Not a directory warning: unable to access '/home/jrn/.config/git/config': Not a directory Compare v1.7.12.1~2^2 (attr:failure to open a .gitattributes file is OK with ENOTDIR, 2012-09-13). Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-08-21warn_on_inaccessible(): a helper to warn on inaccessible pathsJunio C Hamano1-1/+6
The previous series introduced warnings to multiple places, but it could become tiring to see the warning on the same path over and over again during a single run of Git. Making just one function responsible for issuing this warning, we could later choose to keep track of which paths we issued a warning (it would involve a hash table of paths after running them through real_path() or something) in order to reduce noise. Right now we do not know if the noise reduction is necessary, but it still would be a good code reduction/sharing anyway. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-08-21config: warn on inaccessible filesJeff King1-0/+8
Before reading a config file, we check "!access(path, R_OK)" to make sure that the file exists and is readable. If it's not, then we silently ignore it. For the case of ENOENT, this is fine, as the presence of the file is optional. For other cases, though, it may indicate a configuration error (e.g., not having permissions to read the file). Let's print a warning in these cases to let the user know. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-05-22ident: report passwd errors with a more friendly messageJeff King1-0/+12
When getpwuid fails, we give a cute but cryptic message. While it makes sense if you know that getpwuid or identity functions are being called, this code is triggered behind the scenes by quite a few git commands these days (e.g., receive-pack on a remote server might use it for a reflog; the current message is hard to distinguish from an authentication error). Let's switch to something that gives a little more context. While we're at it, we can factor out all of the cut-and-pastes of the "you don't exist" message into a wrapper function. Rather than provide xgetpwuid, let's make it even more specific to just getting the passwd entry for the current uid. That's the only way we use getpwuid anyway, and it lets us make an even more specific error message. The current message also fails to mention errno. While the usual cause for getpwuid failing is that the user does not exist, mentioning errno makes it easier to diagnose these problems. Note that POSIX specifies that errno remain untouched if the passwd entry does not exist (but will be set on actual errors), whereas some systems will return ENOENT or similar for a missing entry. We handle both cases in our wrapper. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-03-07Add more large blob test casesNguyễn Thái Ngọc Duy1-3/+24
New test cases list commands that should work when memory is limited. All memory allocation functions (*) learn to reject any allocation larger than $GIT_ALLOC_LIMIT if set. (*) Not exactly all. Some places do not use x* functions, but malloc/calloc directly, notably diff-delta. These code path should never be run on large blobs. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-05-26read_in_full: always report errorsJeff King1-2/+4
The read_in_full function repeatedly calls read() to fill a buffer. If the first read() returns an error, we notify the caller by returning the error. However, if we read some data and then get an error on a subsequent read, we simply return the amount of data that we did read, and the caller is unaware of the error. This makes the tradeoff that seeing the partial data is more important than the fact that an error occurred. In practice, this is generally not the case; we care more if an error occurred, and should throw away any partial data. I audited the current callers. In most cases, this will make no difference at all, as they do: if (read_in_full(fd, buf, size) != size) error("short read"); However, it will help in a few cases: 1. In sha1_file.c:index_stream, we would fail to notice errors in the incoming stream. 2. When reading symbolic refs in resolve_ref, we would fail to notice errors and potentially use a truncated ref name. 3. In various places, we will get much better error messages. For example, callers of safe_read would erroneously print "the remote end hung up unexpectedly" instead of showing the read error. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-03-17Name make_*_path functions more accuratelyCarlos Martín Nieto1-2/+2
Rename the make_*_path functions so it's clearer what they do, in particlar make clear what the differnce between make_absolute_path and make_nonrelative_path is by renaming them real_path and absolute_path respectively. make_relative_path has an understandable name and is renamed to relative_path to maintain the name convention. The function calls have been replaced 1-to-1 in their usage. Signed-off-by: Carlos Martín Nieto <cmn@elego.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-02-10Merge branch 'maint'Junio C Hamano1-1/+1
* maint: compat: helper for detecting unsigned overflow
2011-02-10compat: helper for detecting unsigned overflowJonathan Nieder1-1/+1
The idiom (a + b < a) works fine for detecting that an unsigned integer has overflowed, but a more explicit unsigned_add_overflows(a, b) might be easier to read. Define such a macro, expanding roughly to ((a) < UINT_MAX - (b)). Because the expansion uses each argument only once outside of sizeof() expressions, it is safe to use with arguments that have side effects. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-12-21Improve error messages when temporary file creation failsArnout Engelen1-4/+28
Before, when creating a temporary file failed, a generic 'Unable to create temporary file' message was printed. In some cases this could lead to confusion as to which directory should be checked for correct permissions etc. This patch adds the template for the temporary filename to the error message, converting it to an absolute path if needed. A test verifies that the template is indeed printed when pointing to a nonexistent or unwritable directory. A copy of the original template is made in case mkstemp clears the template. Signed-off-by: Arnout Engelen <arnouten@bzzt.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-12-21set_try_to_free_routine(NULL) means "do nothing special"Junio C Hamano1-0/+2
This way, the next caller that wants to disable our memory reclamation machinery does not have to define its own do_nothing() stub. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-11-10Remove pack file handling dependency from wrapper.oJonathan Nieder1-3/+2
As v1.7.0-rc0~43 (slim down "git show-index", 2010-01-21) explains, use of xmalloc() brings in a dependency on zlib, the sha1 lib, and the rest of git's object file access machinery via try_to_free_pack_memory. That is overkill when xmalloc is just being used as a convenience wrapper to exit when no memory is available. So defer setting try_to_free_pack_memory as try_to_free_routine until the first packfile is opened in add_packed_git(). After this change, a simple program using xmalloc() and no other functions will not pull in any code from libgit.a aside from wrapper.o and usage.o. Improved-by: René Scharfe <rene.scharfe@lsrfire.ath.cx> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-11-10wrapper: give zlib wrappers their own translation unitJonathan Nieder1-60/+0
Programs using xmalloc() but not git_inflate() require -lz on the linker command line because git_inflate() is in the same translation unit as xmalloc(). Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-11-10path helpers: move git_mkstemp* to wrapper.cJonathan Nieder1-0/+113
git_mkstemp_mode and related functions do not require access to specialized git machinery, unlike some other functions from path.c (like set_shared_perm()). Move them to wrapper.c where the wrapper xmkstemp_mode is defined. This eliminates a dependency of wrapper.o on environment.o via path.o. With typical linkers (e.g., gcc), that dependency makes programs that use functions from wrapper.o and not environment.o or path.o larger than they need to be. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-11-10wrapper: move odb_* to environment.cJonathan Nieder1-37/+0
The odb_mkstemp and odb_pack_keep functions open files under the $GIT_OBJECT_DIRECTORY directory. This requires access to the git configuration which very simple programs do not need. Move these functions to environment.o, closer to their dependencies. This should make it easier for programs to link to wrapper.o without linking to environment.o. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-11-10wrapper: move xmmap() to sha1_file.cJonathan Nieder1-15/+0
wrapper.o depends on sha1_file.o for a number of reasons. One is release_pack_memory(). xmmap function calls mmap, discarding unused pack windows when necessary to relieve memory pressure. Simple git programs using wrapper.o as a friendly libc do not need this functionality. So move xmmap to sha1_file.o, where release_pack_memory() is. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-08-20xmalloc: include size in the failure messageMatthieu Moy1-1/+2
Out-of-memory errors can either be actual lack of memory, or bugs (like code trying to call xmalloc(-1) by mistake). A little more information may help tracking bugs reported by users. Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-06-13Merge branch 'js/try-to-free-stackable'Junio C Hamano1-2/+4
* js/try-to-free-stackable: Do not call release_pack_memory in malloc wrappers when GIT_TRACE is used Have set_try_to_free_routine return the previous routine
2010-05-21Merge branch 'np/malloc-threading'Junio C Hamano1-4/+16
* np/malloc-threading: Thread-safe xmalloc and xrealloc needs a recursive mutex Make xmalloc and xrealloc thread-safe
2010-05-08Have set_try_to_free_routine return the previous routineJohannes Sixt1-2/+4
This effectively requires from the callers of set_try_to_free_routine to treat the try-to-free-routines as a stack. We will need this for the next patch where the only current caller cannot depend on that the previously set routine was the default routine. Signed-off-by: Johannes Sixt <j6t@kdbg.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-03-28Introduce remove_or_warn functionPeter Collingbourne1-0/+5
This patch introduces the remove_or_warn function which is a generalised version of the {unlink,rmdir}_or_warn functions. It takes an additional parameter indicating the mode of the file to be removed. The patch also modifies certain functions to use remove_or_warn where appropriate, and adds a test case for a bug fixed by the use of remove_or_warn. Signed-off-by: Peter Collingbourne <peter@pcc.me.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-03-28Implement the rmdir_or_warn functionPeter Collingbourne1-0/+5
This patch implements an rmdir_or_warn function (like unlink_or_warn but for directories) that uses the generalised warning code in warn_if_unremovable. Signed-off-by: Peter Collingbourne <peter@pcc.me.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-03-28Generalise the unlink_or_warn functionPeter Collingbourne1-5/+7
This patch moves the warning code of the unlink_or_warn function into a separate function named warn_if_unremovable so that it may be reused. Signed-off-by: Peter Collingbourne <peter@pcc.me.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-03-24Make xmalloc and xrealloc thread-safeNicolas Pitre1-4/+16
By providing a hook for the routine responsible for trying to free some memory on malloc failure, we can ensure that the called routine is protected by the appropriate locks when threads are in play. The obvious offender here was pack-objects which was calling xmalloc() within threads while release_pack_memory() is not thread safe. Signed-off-by: Nicolas Pitre <nico@fluxnic.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-02-22Use git_mkstemp_mode and xmkstemp_mode in odb_mkstemp, not chmod later.Matthieu Moy1-3/+7
We used to create 0600 files, and then use chmod to set the group and other permission bits to the umask. This usually has the same effect as a normal file creation with a umask. But in the presence of ACLs, the group permission plays the role of the ACL mask: the "g" bits of newly created files are chosen according to default ACL mask of the directory, not according to the umask, and doing a chmod() on these "g" bits affect the ACL's mask instead of actual group permission. In other words, creating files with 0600 and then doing a chmod to the umask creates files which are unreadable by users allowed in the default ACL. To create the files without breaking ACLs, we let the umask do it's job at the file's creation time, and get rid of the later chmod. Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-02-22git_mkstemp_mode, xmkstemp_mode: variants of gitmkstemps with mode argument.Matthieu Moy1-0/+10
gitmkstemps emulates the behavior of mkstemps, which is usually used to create files in a shared directory like /tmp/, hence, it creates files with permission 0600. Add git_mkstemps_mode() that allows us to specify the desired mode, and make git_mkstemps() a wrapper that always uses 0600 to call it. Later we will use git_mkstemps_mode() when creating pack files. Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-01-26Add xmallocz()Ilari Liusvaara1-4/+11
Add routine for allocating NUL-terminated memory block without risking integer overflow in addition of +1 for NUL byte. [jc: with suggestion from Bill Lear] Signed-off-by: Ilari Liusvaara <ilari.liusvaara@elisanet.fi> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-06-27Convert existing die(..., strerror(errno)) to die_errno()Thomas Rast1-4/+4
Change calls to die(..., strerror(errno)) to use the new die_errno(). In the process, also make slight style adjustments: at least state _something_ about the function that failed (instead of just printing the pathname), and put paths in single quotes. Signed-off-by: Thomas Rast <trast@student.ethz.ch> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-04-29Introduce an unlink(2) wrapper which gives warning if unlink failedAlex Riesen1-0/+16
This seem to be a very common pattern in the current code. The function prints a generic removal failure message, the file name which failed and readable errno presentation. The function preserves errno and always returns the value unlink(2) returned, but prints no message for ENOENT, as it was the most often filtered out in the code calling unlink. Besides, removing a file is anyway the purpose of calling unlink. Signed-off-by: Alex Riesen <raa.lkml@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-02-28Merge branch 'jc/maint-1.6.0-pack-directory'Junio C Hamano1-1/+2
* jc/maint-1.6.0-pack-directory: Fix odb_mkstemp() on AIX
2009-02-26Fix odb_mkstemp() on AIXMike Ralphson1-1/+2
The AIX mkstemp() modifies its template parameter to an empty string if the call fails. The existing code had already recomputed the template, but too late to be good. See also 6ff6af62, which fixed this problem in a different spot. Signed-off-by: Mike Ralphson <mike@abacus.co.uk> Signed-off-by: Johannes Sixt <j6t@kdbg.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-02-25Merge branch 'jc/maint-1.6.0-pack-directory'Junio C Hamano1-0/+32
* jc/maint-1.6.0-pack-directory: Make sure objects/pack exists before creating a new pack
2009-02-25Make sure objects/pack exists before creating a new packJunio C Hamano1-0/+32
In a repository created with git older than f49fb35 (git-init-db: create "pack" subdirectory under objects, 2005-06-27), objects/pack/ directory is not created upon initialization. It was Ok because subdirectories are created as needed inside directories init-db creates, and back then, packfiles were recent invention. After the said commit, new codepaths started relying on the presense of objects/pack/ directory in the repository. This was exacerbated with 8b4eb6b (Do not perform cross-directory renames when creating packs, 2008-09-22) that moved the location temporary pack files are created from objects/ directory to objects/pack/ directory, because moving temporary to the final location was done carefully with lazy leading directory creation. Many packfile related operations in such an old repository can fail mysteriously because of this. This commit introduces two helper functions to make things work better. - odb_mkstemp() is a specialized version of mkstemp() to refactor the code and teach it to create leading directories as needed; - odb_pack_keep() refactors the code to create a ".keep" file while create leading directories as needed. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-01-11Wrap inflate and other zlib routines for better error reportingLinus Torvalds1-0/+60
R. Tyler Ballance reported a mysterious transient repository corruption; after much digging, it turns out that we were not catching and reporting memory allocation errors from some calls we make to zlib. This one _just_ wraps things; it doesn't do the "retry on low memory error" part, at least not yet. It is an independent issue from the reporting. Some of the errors are expected and passed back to the caller, but we die when zlib reports it failed to allocate memory for now. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-20Move read_in_full() and write_in_full() to wrapper.cJunio C Hamano1-0/+38
A few compat/* layer functions call these functions, but we would really want to keep them thin, without depending too much on the libgit proper. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-06-22Shrink the git binary a bit by avoiding unnecessary inline functionsLinus Torvalds1-0/+160
So I was looking at the disgusting size of the git binary, and even with the debugging removed, and using -Os instead of -O2, the size of the text section was pretty high. In this day and age I guess almost a megabyte of text isn't really all that surprising, but it still doesn't exactly make me think "lean and mean". With -Os, a surprising amount of text space is wasted on inline functions that end up just being replicated multiple times, and where performance really isn't a valid reason to inline them. In particular, the trivial wrapper functions like "xmalloc()" are used _everywhere_, and making them inline just duplicates the text (and the string we use to 'die()' on failure) unnecessarily. So this just moves them into a "wrapper.c" file, getting rid of a tiny bit of unnecessary bloat. The following numbers are both with "CFLAGS=-Os": Before: [torvalds@woody git]$ size git text data bss dec hex filename 700460 15160 292184 1007804 f60bc git After: [torvalds@woody git]$ size git text data bss dec hex filename 670540 15160 292184 977884 eebdc git so it saves almost 30k of text-space (it actually saves more than that with the default -O2, but I don't think that's necessarily a very relevant number from a "try to shrink git" standpoint). It might conceivably have a performance impact, but none of this should be _that_ performance critical. The real cost is not generally in the wrapper anyway, but in the code it wraps (ie the cost of "xread()" is all in the read itself, not in the trivial wrapping of it). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>