Commit Graph

346 Commits (d39f04b638f7f862efebb5bf028bad50f6aa9e28)

Author SHA1 Message Date
Jensen Huang d39f04b638 index-pack, unpack-objects: restore missing ->init_fn
Commit 0578f1e66a ("global: adapt callers to use generic hash context helpers")
accidentally removed `->init_fn`, which is required for OpenSSL 3+ SHA1.

This fixes the following error on fetch:
  fatal: fetch-pack: invalid index-pack output

Signed-off-by: Jensen Huang <hmz007@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-18 12:27:33 -07:00
Patrick Steinhardt 0578f1e66a global: adapt callers to use generic hash context helpers
Adapt callers to use generic hash context helpers instead of using the
hash algorithm to update them. This makes the callsites easier to reason
about and removes the possibility that the wrong hash algorithm is used
to update the hash context's state. And as a nice side effect this also
gets rid of a bunch of users of `the_hash_algo`.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-31 10:06:11 -08:00
Patrick Steinhardt 7346e340f1 hash: stop typedeffing the hash context
We generally avoid using `typedef` in the Git codebase. One exception
though is the `git_hash_ctx`, likely because it used to be a union
rather than a struct until the preceding commit refactored it. But now
that it is a normal `struct` there isn't really a need for a typedef
anymore.

Drop the typedef and adapt all callers accordingly.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-31 10:06:10 -08:00
Junio C Hamano f8b9821f7d Merge branch 'jk/pack-header-parse-alignment-fix'
It was possible for "git unpack-objects" and "git index-pack" to
make an unaligned access, which has been corrected.

* jk/pack-header-parse-alignment-fix:
  index-pack, unpack-objects: use skip_prefix to avoid magic number
  index-pack, unpack-objects: use get_be32() for reading pack header
  parse_pack_header_option(): avoid unaligned memory writes
  packfile: factor out --pack_header argument parsing
  bswap.h: squelch potential sparse -Wcast-truncate warnings
2025-01-28 13:02:23 -08:00
Junio C Hamano f0a371a39d Merge branch 'jc/show-usage-help'
The help text from "git $cmd -h" appear on the standard output for
some $cmd and the standard error for others.  The built-in commands
have been fixed to show them on the standard output consistently.

* jc/show-usage-help:
  builtin: send usage() help text to standard output
  oddballs: send usage() help text to standard output
  builtins: send usage_with_options() help text to standard output
  usage: add show_usage_if_asked()
  parse-options: add show_usage_with_options_if_asked()
  t0012: optionally check that "-h" output goes to stdout
2025-01-28 13:02:22 -08:00
Junio C Hamano 7b39a128c8 Merge branch 'ps/the-repository'
More code paths have a repository passed through the callchain,
instead of assuming the primary the_repository object.

* ps/the-repository:
  match-trees: stop using `the_repository`
  graph: stop using `the_repository`
  add-interactive: stop using `the_repository`
  tmp-objdir: stop using `the_repository`
  resolve-undo: stop using `the_repository`
  credential: stop using `the_repository`
  mailinfo: stop using `the_repository`
  diagnose: stop using `the_repository`
  server-info: stop using `the_repository`
  send-pack: stop using `the_repository`
  serve: stop using `the_repository`
  trace: stop using `the_repository`
  pager: stop using `the_repository`
  progress: stop using `the_repository`
2025-01-21 08:44:54 -08:00
Jeff King 98046591b9 index-pack, unpack-objects: use skip_prefix to avoid magic number
When parsing --pack_header=, we manually skip 14 bytes to the data.
Let's use skip_prefix() to do this automatically.

Note that we overwrite our pointer to the front of the string, so we
have to add more context to the error message. We could avoid this by
declaring an extra pointer to hold the value, but I think the modified
message is actually preferable; it should give translators a bit more
context.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-21 08:42:56 -08:00
Jeff King f1299bff26 index-pack, unpack-objects: use get_be32() for reading pack header
Both of these commands read the incoming pack into a static unsigned
char buffer in BSS, and then parse it by casting the start of the buffer
to a struct pack_header. This can result in SIGBUS on some platforms if
the compiler doesn't place the buffer in a position that is properly
aligned for 4-byte integers.

This reportedly happens with unpack-objects (but not index-pack) on
sparc64 when compiled with clang (but not gcc). But we are definitely in
the wrong in both spots; since the buffer's type is unsigned char, we
can't depend on larger alignment. When it works it is only because we
are lucky.

We'll fix this by switching to get_be32() to read the headers (just like
the last few commits similarly switched us to put_be32() for writing
into the same buffer).

It would be nice to factor this out into a common helper function, but
the interface ends up quite awkward. Either the caller needs to hardcode
how many bytes we'll need, or it needs to pass us its fill()/use()
functions as pointers. So I've just fixed both spots in the same way;
this is not code that is likely to be repeated a third time (most of the
pack reading code uses an mmap'd buffer, which should be properly
aligned).

I did make one tweak to the shared code: our pack_version_ok() macro
expects us to pass the big-endian value we'd get by casting. We can
introduce a "native" variant which uses the host integer ordering.

Reported-by: Koakuma <koachan@protonmail.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-21 08:42:56 -08:00
Jeff King 798e0f4516 packfile: factor out --pack_header argument parsing
Both index-pack and unpack-objects accept a --pack_header argument. This
is an undocumented internal argument used by receive-pack and fetch to
pass along information about the header of the pack, which they've
already read from the incoming stream.

In preparation for a bugfix, let's factor the duplicated code into a
common helper.

The callers are still responsible for identifying the option. While this
could likewise be factored out, it is more flexible this way (e.g., if
they ever started using parse-options and wanted to handle both the
stuck and unstuck forms).

Likewise, the callers are responsible for reporting errors, though they
both just call die(). I've tweaked unpack-objects to match index-pack in
marking the error for translation.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-21 08:42:55 -08:00
Junio C Hamano f66d1423f5 builtin: send usage() help text to standard output
Using the show_usage_and_exit_if_asked() helper we introduced
earlier, fix callers of usage() that want to show the help text when
explicitly asked by the end-user.  The help text now goes to the
standard output stream for them.

These are the bog standard "if we got only '-h', then that is a
request for help" callers.  Their

	if (argc == 2 && !strcmp(argv[1], "-h"))
		usage(message);

are simply replaced with

	show_usage_and_exit_if_asked(argc, argv, message);

With this, the built-ins tested by t0012 all send their help text to
their standard output stream, so the check in t0012 that was half
tightened earlier is now fully tightened to insist on standard error
stream being empty.

Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-17 13:30:03 -08:00
Junio C Hamano fc89d14c63 Revert barrier-based LSan threading race workaround
The extra "barrier" approach was too much code whose sole purpose
was to work around a race that is not even ours (i.e. in LSan's
teardown code).

In preparation for queuing a solution taking a much-less-invasive
approach, let's revert them.
2025-01-01 14:13:01 -08:00
Jeff King 526c0a851b index-pack: work around LSan threading race with barrier
We sometimes get false positives from our linux-leaks CI job because of
a race in LSan itself. The problem is that one thread is still
initializing its stack in LSan's code (and allocating memory to do so)
while anothe thread calls die(), taking down the whole process and
triggering a leak check.

The problem is described in more detail in 993d38a066 (index-pack: spawn
threads atomically, 2024-01-05), which tried to fix it by pausing worker
threads until all calls to pthread_create() had completed. But that's
not enough to fix the problem, because the LSan setup code runs in the
threads themselves. So even though pthread_create() has returned, we
have no idea if all threads actually finished their setup before letting
any of them do real work.

We can fix that by using a barrier inside the threads themselves,
waiting for all of them to hit the start of their main function before
any of them proceed.

You can test for the race by running:

  make SANITIZE=leak THREAD_BARRIER_PTHREAD=YesOnLinux
  cd t
  ./t5309-pack-delta-cycles.sh --stress

which fails quickly before this patch, and should run indefinitely
without it.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-30 06:18:58 -08:00
Jeff King ca9d60f246 Revert "index-pack: spawn threads atomically"
This reverts commit 993d38a066.

That commit was trying to solve a race between LSan setting up the
threads stack and another thread calling exit(), by making sure that all
pthread_create() calls have finished before doing any work that might
trigger the exit().

But that isn't sufficient. The setup code actually runs in the
individual threads themselves, not in the spawning thread's call to
pthread_create(). So while it may have improved the race a bit, you can
still trigger it pretty quickly with:

  make SANITIZE=leak
  cd t
  ./t5309-pack-delta-cycles.sh --stress

Let's back out that failed attempt so we can try again.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-30 06:18:57 -08:00
Junio C Hamano 4156b6a741 Merge branch 'ps/build-sign-compare'
Start working to make the codebase buildable with -Wsign-compare.

* ps/build-sign-compare:
  t/helper: don't depend on implicit wraparound
  scalar: address -Wsign-compare warnings
  builtin/patch-id: fix type of `get_one_patchid()`
  builtin/blame: fix type of `length` variable when emitting object ID
  gpg-interface: address -Wsign-comparison warnings
  daemon: fix type of `max_connections`
  daemon: fix loops that have mismatching integer types
  global: trivial conversions to fix `-Wsign-compare` warnings
  pkt-line: fix -Wsign-compare warning on 32 bit platform
  csum-file: fix -Wsign-compare warning on 32-bit platform
  diff.h: fix index used to loop through unsigned integer
  config.mak.dev: drop `-Wno-sign-compare`
  global: mark code units that generate warnings with `-Wsign-compare`
  compat/win32: fix -Wsign-compare warning in "wWinMain()"
  compat/regex: explicitly ignore "-Wsign-compare" warnings
  git-compat-util: introduce macros to disable "-Wsign-compare" warnings
2024-12-23 09:32:11 -08:00
Patrick Steinhardt 1f7e6478dc progress: stop using `the_repository`
Stop using `the_repository` in the "progress" subsystem by passing in a
repository when initializing `struct progress`. Furthermore, store a
pointer to the repository in that struct so that we can pass it to the
trace2 API when logging information.

Adjust callers accordingly by using `the_repository`. While there may be
some callers that have a repository available in their context, this
trivial conversion allows for easier verification and bubbles up the use
of `the_repository` by one level.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-18 10:44:30 -08:00
Junio C Hamano 913a1e157c Merge branch 'ps/build-sign-compare' into ps/the-repository
* ps/build-sign-compare:
  t/helper: don't depend on implicit wraparound
  scalar: address -Wsign-compare warnings
  builtin/patch-id: fix type of `get_one_patchid()`
  builtin/blame: fix type of `length` variable when emitting object ID
  gpg-interface: address -Wsign-comparison warnings
  daemon: fix type of `max_connections`
  daemon: fix loops that have mismatching integer types
  global: trivial conversions to fix `-Wsign-compare` warnings
  pkt-line: fix -Wsign-compare warning on 32 bit platform
  csum-file: fix -Wsign-compare warning on 32-bit platform
  diff.h: fix index used to loop through unsigned integer
  config.mak.dev: drop `-Wno-sign-compare`
  global: mark code units that generate warnings with `-Wsign-compare`
  compat/win32: fix -Wsign-compare warning in "wWinMain()"
  compat/regex: explicitly ignore "-Wsign-compare" warnings
  git-compat-util: introduce macros to disable "-Wsign-compare" warnings
2024-12-18 10:43:16 -08:00
Junio C Hamano ededd0d5dc Merge branch 'jt/fix-fattening-promisor-fetch'
Fix performance regression of a recent "fatten promisor pack with
local objects" protection against an unwanted gc.

* jt/fix-fattening-promisor-fetch:
  index-pack --promisor: also check commits' trees
  index-pack --promisor: don't check blobs
  index-pack --promisor: dedup before checking links
2024-12-15 17:54:31 -08:00
Junio C Hamano ca43bd2562 Merge branch 'kn/midx-wo-the-repository'
Yet another "pass the repository through the callchain" topic.

* kn/midx-wo-the-repository:
  midx: inline the `MIDX_MIN_SIZE` definition
  midx: pass down `hash_algo` to functions using global variables
  midx: pass `repository` to `load_multi_pack_index`
  midx: cleanup internal usage of `the_repository` and `the_hash_algo`
  midx-write: pass down repository to `write_midx_file[_only]`
  write-midx: add repository field to `write_midx_context`
  midx-write: use `revs->repo` inside `read_refs_snapshot`
  midx-write: pass down repository to static functions
  packfile.c: remove unnecessary prepare_packed_git() call
  midx: add repository to `multi_pack_index` struct
  config: make `packed_git_(limit|window_size)` non-global variables
  config: make `delta_base_cache_limit` a non-global variable
  packfile: pass down repository to `for_each_packed_object`
  packfile: pass down repository to `has_object[_kept]_pack`
  packfile: pass down repository to `odb_pack_name`
  packfile: pass `repository` to static function in the file
  packfile: use `repository` from `packed_git` directly
  packfile: add repository to struct `packed_git`
2024-12-13 07:33:44 -08:00
Jonathan Tan 1a14c857db index-pack --promisor: also check commits' trees
Commit c08589efdc (index-pack: repack local links into promisor packs,
2024-11-01) seems to contain an oversight in that the tree of a commit
is not checked. Teach git to check these trees.

The fix slows down a fetch from a certain repo at $DAYJOB from 2m2.127s
to 2m45.052s, but in order to make the fetch correct, it seems worth it.

In order to test this, we could create server and client repos as
follows...

 C   S
  \ /
   O

(O and C are commits both on the client and server. S is a commit
only on the server. C and S have the same tree but different commit
messages. The diff between O and C is non-zero.)

...and then, from the client, fetch S from the server.

In theory, the client declares "have C" and the server can use this
information to exclude S's tree (since it knows that the client has C's
tree, which is the same as S's tree). However, it is also possible for
the server to compute that it needs to send S and not O, and proceed
from there; therefore the objects of C are not considered at all when
determining what to send in the packfile. In order to prevent a test of
client functionality from having such a dependence on server behavior, I
have not included such a test.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-10 08:53:59 +09:00
Jonathan Tan 36198026d8 index-pack --promisor: don't check blobs
As a follow-up to the parent of this commit, it was found that not
checking for the existence of blobs linked from trees sped up the fetch
from 24m47.815s to 2m2.127s. Teach Git to do that.

The tradeoff of not checking blobs is documented in a code comment.

(Blobs may also be linked from tag objects, but it is impossible to know
the type of an object linked from a tag object without looking it up in
the object database, so the code for that is untouched.)

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-10 08:53:59 +09:00
Jonathan Tan 911d14203c index-pack --promisor: dedup before checking links
Commit c08589efdc (index-pack: repack local links into promisor packs,
2024-11-01) fixed a bug with what was believed to be a negligible
decrease in performance [1] [2]. But at $DAYJOB, with at least one repo,
it was found that the decrease in performance was very significant.

Looking at the patch, whenever we parse an object in the packfile to
be indexed, we check the targets of all its outgoing links for its
existence. However, this could be optimized by first collecting all such
targets into an oidset (thus deduplicating them) before checking. Teach
Git to do that.

On a certain fetch from the aforementioned repo, this improved
performance from approximately 7 hours to 24m47.815s. This number will
be further reduced in a subsequent patch.

[1] https://lore.kernel.org/git/CAG1j3zGiNMbri8rZNaF0w+yP+6OdMz0T8+8_Wgd1R_p1HzVasg@mail.gmail.com/
[2] https://lore.kernel.org/git/20241105212849.3759572-1-jonathantanmy@google.com/

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-10 08:53:59 +09:00
Patrick Steinhardt 41f43b8243 global: mark code units that generate warnings with `-Wsign-compare`
Mark code units that generate warnings with `-Wsign-compare`. This
allows for a structured approach to get rid of all such warnings over
time in a way that can be easily measured.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-06 20:20:02 +09:00
Junio C Hamano 33833ed08b Merge branch 'kn/the-repository' into kn/midx-wo-the-repository
* kn/the-repository:
  packfile.c: remove unnecessary prepare_packed_git() call
  midx: add repository to `multi_pack_index` struct
  config: make `packed_git_(limit|window_size)` non-global variables
  config: make `delta_base_cache_limit` a non-global variable
  packfile: pass down repository to `for_each_packed_object`
  packfile: pass down repository to `has_object[_kept]_pack`
  packfile: pass down repository to `odb_pack_name`
  packfile: pass `repository` to static function in the file
  packfile: use `repository` from `packed_git` directly
  packfile: add repository to struct `packed_git`
2024-12-04 10:31:46 +09:00
Karthik Nayak d6b2d21fbf config: make `delta_base_cache_limit` a non-global variable
The `delta_base_cache_limit` variable is a global config variable used
by multiple subsystems. Let's make this non-global, by adding this
variable independently to the subsystems where it is used.

First, add the setting to the `repo_settings` struct, this provides
access to the config in places where the repository is available. Use
this in `packfile.c`.

In `index-pack.c` we add it to the `pack_idx_option` struct and its
constructor. While the repository struct is available here, it may not
be set  because `git index-pack` can be used without a repository.

In `gc.c` add it to the `gc_config` struct and also the constructor
function. The gc functions currently do not have direct access to a
repository struct.

These changes are made to remove the usage of `delta_base_cache_limit`
as a global variable in `packfile.c`. This brings us one step closer to
removing the `USE_THE_REPOSITORY_VARIABLE` definition in `packfile.c`
which we complete in the next patch.

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-04 08:21:55 +09:00
Karthik Nayak 873b00597b packfile: pass down repository to `odb_pack_name`
The function `odb_pack_name` currently relies on the global variable
`the_repository`. To eliminate global variable usage in `packfile.c`, we
should progressively shift the dependency on the_repository to higher
layers.

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-04 08:21:54 +09:00
Karthik Nayak 2cf3fe63f6 packfile: add repository to struct `packed_git`
The struct `packed_git` holds information regarding a packed object
file. Let's add the repository variable to this object, to represent the
repository that this packfile belongs to. This helps remove dependency
on the global `the_repository` object in `packfile.c` by simply using
repository information now readily available in the struct.

We do need to consider that a packfile could be part of the alternates
of a repository, but considering that we only have one repository struct
and also that we currently anyways use 'the_repository', we should be
OK with this change.

We also modify `alloc_packed_git` to ensure that the repository is added
to newly created `packed_git` structs. This requires modifying the
function and all its callee to pass the repository object down the
levels.

Helped-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-04 08:21:53 +09:00
Junio C Hamano 1f3d9b9814 Merge branch 'jt/index-pack-allow-promisor-only-while-fetching'
We now ensure "index-pack" is used with the "--promisor" option
only during a "git fetch".

* jt/index-pack-allow-promisor-only-while-fetching:
  index-pack: teach --promisor to forbid pack name
2024-11-27 07:57:09 +09:00
Junio C Hamano 93905d3b70 Merge branch 'bc/c23'
C23 compatibility updates.

* bc/c23:
  reflog: rename unreachable
  index-pack: rename struct thread_local
2024-11-27 07:57:05 +09:00
Jonathan Tan 1f2be8bed6 index-pack: teach --promisor to forbid pack name
Currently,

 - Running "index-pack --promisor" outside a repo segfaults.
 - It may be confusing to a user that running "index-pack --promisor"
   within a repo may make changes to the repo's object DB, especially
   since the packs indexed by the index-pack invocation may not even be
   related to the repo.

As discussed in [1] and [2], teaching --promisor to forbid a packfile
name solves both these problems. This combination of arguments requires
a repo (since we are writing the resulting .pack and .idx to it) and it
is clear that the files are related to the repo.

Currently, Git uses "index-pack --promisor" only when fetching into
a repo, so it could be argued that we should teach "index-pack" a
new argument (say, "--fetching-mode") instead of tying --promisor to
a generic argument like the packfile name. However, this --promisor
feature could conceivably be used whenever we have a packfile that is
known to come from the promisor remote (whether obtained through Git's
fetch protocol or through other means) so not using a new argument seems
reasonable - one could envision a user-made script obtaining a packfile
and then running "index-pack --promisor --stdin", for example. In fact,
it might be possible to relax the restriction further (say, by also
allowing --promisor when indexing a packfile that is in the object DB),
but relaxing the restriction is backwards-compatible so we can revisit
that later.

One thing to watch out for is the possibility of a future Git feature
that indexes a pack in the context of a repo, but does not necessarily
write the resulting pack to it (and does not necessarily desire to
make any changes to the object DB). One such feature would be fetch
quarantine, which might need the repo context in order to detect
hash collisions, but would also need to ensure that the object DB
is undisturbed in case the fetch fails for whatever reason, even if
the reason occurs only after the indexing is complete. It may not be
obvious to the implementer of such a feature that "index-pack" could
sometimes write packs other than the indexed pack to the object DB,
but there are already other ways that "fetch" could write to the object
DB (in particular, packfile URIs and bundle URIs), so hopefully the
implementation of this future feature would already include a test that
the object DB be undisturbed.

This change requires the change to t5300 by 1f52cdfacb (index-pack:
document and test the --promisor option, 2022-03-09) to be undone.
(--promisor is already tested indirectly, so we don't need the explicit
test here any more.)

[1] https://lore.kernel.org/git/20241114005652.GC1140565@coredump.intra.peff.net/
[2] https://lore.kernel.org/git/20241119185345.GB15723@coredump.intra.peff.net/

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-11-20 10:37:56 +09:00
brian m. carlson e8b3bcf491 index-pack: rename struct thread_local
"thread_local" is a keyword in C23.  To make sure that our code compiles
on a wide variety of C versions, rename struct thread_local to "struct
thread_local_data" to avoid a conflict.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-11-18 09:42:08 +09:00
Jonathan Tan c08589efdc index-pack: repack local links into promisor packs
Teach index-pack to, when processing the objects in a pack with
--promisor specified on the CLI, repack local objects (and the local
objects that they refer to, recursively) referenced by these objects
into promisor packs.

This prevents the situation in which, when fetching from a promisor
remote, we end up with promisor objects (newly fetched) referring
to non-promisor objects (locally created prior to the fetch). This
situation may arise if the client had previously pushed objects to the
remote, for example. One issue that arises in this situation is that,
if the non-promisor objects become inaccessible except through promisor
objects (for example, if the branch pointing to them has moved to
point to the promisor object that refers to them), then GC will garbage
collect them. There are other ways to solve this, but the simplest
seems to be to enforce the invariant that we don't have promisor objects
referring to non-promisor objects.

This repacking is done from index-pack to minimize the performance
impact. During a fetch, the only time most objects are fully inflated
in memory is when their object ID is computed, so we also scan the
objects (to see which objects they refer to) during this time.

Also to minimize the performance impact, an object is calculated to be
local if it's a loose object or present in a non-promisor pack. (If it's
also in a promisor pack or referred to by an object in a promisor pack,
it is technically already a promisor object. But a misidentification
of a promisor object as a non-promisor object is relatively benign
here - we will thus repack that promisor object into a promisor pack,
duplicating it in the object store, but there is no correctness issue,
just an issue of inefficiency.)

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-11-12 10:18:16 +09:00
Patrick Steinhardt 2f0ee051dd pack-write: fix return parameter of `write_rev_file_order()`
While the return parameter of `write_rev_file_order()` is a string
constant, the function may indeed return an allocated string when its
first parameter is a `NULL` pointer. This makes for a confusing calling
convention, where callers need to be aware of these intricate ownership
rules and cast away the constness to free the string in some cases.

Adapt the function and its caller `write_rev_file()` to always return an
allocated string and adapt callers to always free the return value.

Note that this requires us to also adapt `rename_tmp_packfile()`, which
compares the pointers to packfile data with each other. Now that the
path of the reverse index file gets allocated unconditionally the check
will always fail. This is fixed by using strcmp(3P) instead, which also
feels way less fragile.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-09-30 11:23:08 -07:00
Junio C Hamano b8e318ea58 Merge branch 'jc/pass-repo-to-builtins'
The convention to calling into built-in command implementation has
been updated to pass the repository, if known, together with the
prefix value.

* jc/pass-repo-to-builtins:
  add: pass in repo variable instead of global the_repository
  builtin: remove USE_THE_REPOSITORY for those without the_repository
  builtin: remove USE_THE_REPOSITORY_VARIABLE from builtin.h
  builtin: add a repository parameter for builtin functions
2024-09-23 10:35:09 -07:00
John Cai 03eae9afb4 builtin: remove USE_THE_REPOSITORY_VARIABLE from builtin.h
Instead of including USE_THE_REPOSITORY_VARIABLE by default on every
builtin, remove it from builtin.h and add it to all the builtins that
include builtin.h (by definition, that means all builtins/*.c).

Also, remove the include statement for repository.h since it gets
brought in through builtin.h.

The next step will be to migrate each builtin
from having to use the_repository.

Signed-off-by: John Cai <johncai86@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-09-13 14:32:24 -07:00
John Cai 9b1cb5070f builtin: add a repository parameter for builtin functions
In order to reduce the usage of the global the_repository, add a
parameter to builtin functions that will get passed a repository
variable.

This commit uses UNUSED on most of the builtin functions, as subsequent
commits will modify the actual builtins to pass the repository parameter
down.

Signed-off-by: John Cai <johncai86@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-09-13 14:27:08 -07:00
Patrick Steinhardt b2dbf97f47 builtin/index-pack: fix segfaults when running outside of a repo
It was reported that git-verify-pack(1) has started to crash with Git
v2.46.0 when run outside of a repository. This is another fallout from
c8aed5e8da (repository: stop setting SHA1 as the default object hash,
2024-05-07), where we have stopped setting the default hash algorithm
for `the_repository`. Consequently, code that relies on `the_hash_algo`
will now crash when it hasn't explicitly been initialized, which may be
the case when running outside of a Git repository.

The crash is not in git-verify-pack(1) but instead in git-index-pack(1),
which gets called by the former. Ideally, both of these programs should
be able to identify the hash algorithm used by the packfile and index
without having to rely on external information. But unfortunately, the
format for neither of them is completely self-describing, so it is not
possible to derive that information. This is a design issue that we
should address by introducing a new packfile version that encodes its
object hash.

For now though the more important fix is to not make either of these
programs crash anymore, which we do by falling back to SHA1 when the
object hash is unconfigured. This pessimizes reading packfiles which
use a different hash than SHA1, but restores previous behaviour.

Reported-by: Ilya K <me@0upti.me>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-09-04 07:40:00 -07:00
Patrick Steinhardt 9da95bda74 hash: require hash algorithm in `oidread()` and `oidclr()`
Both `oidread()` and `oidclr()` use `the_repository` to derive the hash
function that shall be used. Require callers to pass in the hash
algorithm to get rid of this implicit dependency.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-06-14 10:26:32 -07:00
Patrick Steinhardt f4836570a7 hash: require hash algorithm in `hasheq()`, `hashcmp()` and `hashclr()`
Many of our hash functions have two variants, one receiving a `struct
git_hash_algo` and one that derives it via `the_repository`. Adapt all
of those functions to always require the hash algorithm as input and
drop the variants that do not accept one.

As those functions are now independent of `the_repository`, we can move
them from "hash.h" to "hash-ll.h".

Note that both in this and subsequent commits in this series we always
just pass `the_repository->hash_algo` as input even if it is obvious
that there is a repository in the context that we should be using the
hash from instead. This is done to be on the safe side and not introduce
any regressions. All callsites should eventually be amended to use a
repo passed via parameters, but this is outside the scope of this patch
series.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-06-14 10:26:32 -07:00
Junio C Hamano fa6c383309 unpack: replace xwrite() loop with write_in_full()
We have two packfile stream consumers, index-pack and
unpack-objects, that allow excess payload after the packfile stream
data. Their code to relay excess data hasn't changed significantly
since their original implementation that appeared in 67e5a5ec
(git-unpack-objects: re-write to read from stdin, 2005-06-28) and
9bee2478 (mimic unpack-objects when --stdin is used with index-pack,
2006-10-25).

These code blocks contain hand-rolled loops using xwrite(), written
before our write_in_full() helper existed. This helper now provides
the same functionality.

Replace these loops with write_in_full() for shorter, clearer
code. Update related variables accordingly.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-03-02 11:12:16 -08:00
Junio C Hamano 2c90347a94 Merge branch 'jc/index-pack-fsck-levels'
The "--fsck-objects" option of "git index-pack" now can take the
optional parameter to tweak severity of different fsck errors.

* jc/index-pack-fsck-levels:
  index-pack: --fsck-objects to take an optional argument for fsck msgs
  index-pack: test and document --strict=<msg-id>=<severity>...
2024-02-08 13:20:33 -08:00
John Cai 0f8edf7317 index-pack: --fsck-objects to take an optional argument for fsck msgs
git-index-pack has a --strict option that can take an optional argument
to provide a list of fsck issues to change their severity.
--fsck-objects does not have such a utility, which would be useful if
one would like to be more lenient or strict on data integrity in a
repository.

Like --strict, allow --fsck-objects to also take a list of fsck msgs to
change the severity.

Remove the "For internal use only" note for --fsck-objects, and document
the option. This won't often be used by the normal end user, but it
turns out it is useful for Git forges like GitLab.

Reviewed-by: Christian Couder <christian.couder@gmail.com>
Signed-off-by: John Cai <johncai86@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-02-01 11:09:53 -08:00
John Cai 2811019f47 index-pack: test and document --strict=<msg-id>=<severity>...
5d477a334a (fsck (receive-pack): allow demoting errors to warnings,
2015-06-22) allowed a list of fsck msg to downgrade to be passed to
--strict. However this is a hidden argument that was not documented nor
tested. Though it is true that most users would not call this option
directly, (nor use index-pack for that matter) it is still useful to
document and test this feature.

Reviewed-by: Christian Couder <christian.couder@gmail.com>
Signed-off-by: John Cai <johncai86@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-02-01 11:09:53 -08:00
Junio C Hamano b27f67aa93 Merge branch 'jk/index-pack-lsan-false-positive-fix'
Fix false positive reported by leak sanitizer.

* jk/index-pack-lsan-false-positive-fix:
  index-pack: spawn threads atomically
2024-01-16 10:11:58 -08:00
Jeff King 993d38a066 index-pack: spawn threads atomically
The t5309 script triggers a racy false positive with SANITIZE=leak on a
multi-core system. Running with "--stress --run=6" usually fails within
10 seconds or so for me, complaining with something like:

    + git index-pack --fix-thin --stdin
    fatal: REF_DELTA at offset 46 already resolved (duplicate base 01d7713666f4de822776c7622c10f1b07de280dc?)

    =================================================================
    ==3904583==ERROR: LeakSanitizer: detected memory leaks

    Direct leak of 32 byte(s) in 1 object(s) allocated from:
        #0 0x7fa790d01986 in __interceptor_realloc ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:98
        #1 0x7fa790add769 in __pthread_getattr_np nptl/pthread_getattr_np.c:180
        #2 0x7fa790d117c5 in __sanitizer::GetThreadStackTopAndBottom(bool, unsigned long*, unsigned long*) ../../../../src/libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cpp:150
        #3 0x7fa790d11957 in __sanitizer::GetThreadStackAndTls(bool, unsigned long*, unsigned long*, unsigned long*, unsigned long*) ../../../../src/libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cpp:598
        #4 0x7fa790d03fe8 in __lsan::ThreadStart(unsigned int, unsigned long long, __sanitizer::ThreadType) ../../../../src/libsanitizer/lsan/lsan_posix.cpp:51
        #5 0x7fa790d013fd in __lsan_thread_start_func ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:440
        #6 0x7fa790adc3eb in start_thread nptl/pthread_create.c:444
        #7 0x7fa790b5ca5b in clone3 ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81

    SUMMARY: LeakSanitizer: 32 byte(s) leaked in 1 allocation(s).
    Aborted

What happens is this:

  0. We construct a bogus pack with a duplicate object in it and trigger
     index-pack.

  1. We spawn a bunch of worker threads to resolve deltas (on my system
     it is 16 threads).

  2. One of the threads sees the duplicate object and bails by calling
     exit(), taking down all of the threads. This is expected and is the
     point of the test.

  3. At the time exit() is called, we may still be spawning threads from
     the main process via pthread_create(). LSan hooks thread creation
     to update its book-keeping; it has to know where each thread's
     stack is (so it can find entry points for reachable memory). So it
     calls pthread_getattr_np() to get information about the new thread.
     That may allocate memory that must be freed with a matching call to
     pthread_attr_destroy(). Probably LSan does that immediately, but
     if you're unlucky enough, the exit() will happen while it's between
     those two calls, and the allocated pthread_attr_t appears as a
     leak.

This isn't a real leak. It's not even in our code, but rather in the
LSan instrumentation code. So we could just ignore it. But the false
positive can cause people to waste time tracking it down.

It's possibly something that LSan could protect against (e.g., cover the
getattr/destroy pair with a mutex, and then in the final post-exit()
check for leaks try to take the same mutex). But I don't know enough
about LSan to say if that's a reasonable approach or not (or if my
analysis is even completely correct).

In the meantime, it's pretty easy to avoid the race by making creation
of the worker threads "atomic". That is, we'll spawn all of them before
letting any of them start to work. That's easy to do because we already
have a work_lock() mutex for handing out that work. If the main process
takes it, then all of the threads will immediately block until we've
finished spawning and released it.

This shouldn't make any practical difference for non-LSan runs. The
thread spawning is quick, and could happen before any worker thread gets
scheduled anyway.

Probably other spots that use threads are subject to the same issues.
But since we have to manually insert locking (and since this really is
kind of a hack), let's not bother with them unless somebody experiences
a similar racy false-positive in practice.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-01-05 08:40:56 -08:00
Elijah Newren eea0e59ffb treewide: remove unnecessary includes in source files
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>
2023-12-26 12:04:31 -08:00
Junio C Hamano 331f20d52d Merge branch 'ew/hash-with-openssl-evp'
Fix-up new-ish code to support OpenSSL EVP API.

* ew/hash-with-openssl-evp:
  treewide: fix various bugs w/ OpenSSL 3+ EVP API
2023-09-13 10:07:57 -07:00
Eric Wong e0b8c84240 treewide: fix various bugs w/ OpenSSL 3+ EVP API
The OpenSSL 3+ EVP API for SHA-* cannot support our prior use cases
supported by other SHA-* implementations.  It has the following
differences:

1. ->init_fn is required before all use
2. struct assignments don't work and requires ->clone_fn
3. can't support ->update_fn after ->final_*fn

While fixing cases 1 and 2 is merely the matter of calling ->init_fn and
->clone_fn as appropriate, fixing case 3 requires calling ->final_*fn on
a temporary context that's cloned from the primary context.

Reported-by: Bagas Sanjaya <bagasdotme@gmail.com>
Link: https://lore.kernel.org/ZPCL11k38PXTkFga@debian.me/
Helped-by: brian m. carlson <sandals@crustytoothpaste.net>
Fixes: 3e440ea0ab ("sha256: avoid functions deprecated in OpenSSL 3+")
Fixes: bda9c12073 ("avoid SHA-1 functions deprecated in OpenSSL 3+")
Signed-off-by: Eric Wong <e@80x24.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-08-31 22:26:01 -07:00
Junio C Hamano c5fcd34e1b Merge branch 'jk/unused-parameter'
Mark-up unused parameters in the code so that we can eventually
enable -Wunused-parameter by default.

* jk/unused-parameter:
  t/helper: mark unused callback void data parameters
  tag: mark unused parameters in each_tag_name_fn callbacks
  rev-parse: mark unused parameter in for_each_abbrev callback
  replace: mark unused parameter in each_mergetag_fn callback
  replace: mark unused parameter in ref callback
  merge-tree: mark unused parameter in traverse callback
  fsck: mark unused parameters in various fsck callbacks
  revisions: drop unused "opt" parameter in "tweak" callbacks
  count-objects: mark unused parameter in alternates callback
  am: mark unused keep_cr parameters
  http-push: mark unused parameter in xml callback
  http: mark unused parameters in curl callbacks
  do_for_each_ref_helper(): mark unused repository parameter
  test-ref-store: drop unimplemented reflog-expire command
2023-07-25 12:05:24 -07:00
Junio C Hamano ce481ac8b3 Merge branch 'cw/compat-util-header-cleanup'
Further shuffling of declarations across header files to streamline
file dependencies.

* cw/compat-util-header-cleanup:
  git-compat-util: move alloc macros to git-compat-util.h
  treewide: remove unnecessary includes for wrapper.h
  kwset: move translation table from ctype
  sane-ctype.h: create header for sane-ctype macros
  git-compat-util: move wrapper.c funcs to its header
  git-compat-util: move strbuf.c funcs to its header
2023-07-17 11:30:42 -07:00
Jeff King 0b4e9013f1 fsck: mark unused parameters in various fsck callbacks
There are a few callback functions which are used with the fsck code,
but it's natural that not all callbacks need all parameters. For
reporting, even something as obvious as "the oid of the object which had
a problem" is not always used, as some callers are only checking a
single object in the first place. And for both reporting and walking,
things like void data pointers and the fsck_options aren't always
necessary.

But since each such parameter is used by _some_ callback, we have to
keep them in the interface. Mark the unused ones in specific callbacks
to avoid triggering -Wunused-parameter.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-07-13 17:24:00 -07:00