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Ævar Arnfjörð Bjarmason 44439c1c58 object-file API: have hash_object_file() take "enum object_type"
Change the hash_object_file() function to take an "enum
object_type".

Since a preceding commit all of its callers are passing either
"{commit,tree,blob,tag}_type", or the result of a call to type_name(),
the parse_object() caller that would pass NULL is now using
stream_object_signature().

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-02-25 17:16:32 -08:00
Ævar Arnfjörð Bjarmason 0f156dbb04 object-file API: split up and simplify check_object_signature()
Split up the check_object_signature() function into that non-streaming
version (it accepts an already filled "buf"), and a new
stream_object_signature() which will retrieve the object from storage,
and hash it on-the-fly.

All of the callers of check_object_signature() were effectively
calling two different functions, if we go by cyclomatic
complexity. I.e. they'd either take the early "if (map)" branch and
return early, or not. This has been the case since the "if (map)"
condition was added in 090ea12671 (parse_object: avoid putting whole
blob in core, 2012-03-07).

We can then further simplify the resulting check_object_signature()
function since only one caller wanted to pass a non-NULL "buf" and a
non-NULL "real_oidp". That "read_loose_object()" codepath used by "git
fsck" can instead use hash_object_file() followed by oideq().

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-02-25 17:16:31 -08:00
Ævar Arnfjörð Bjarmason ee213de22d object API users + docs: check <0, not !0 with check_object_signature()
Change those users of the object API that misused
check_object_signature() by assuming it returned any non-zero when the
OID didn't match the expected value to check <0 instead. In practice
all of this code worked before, but it wasn't consistent with rest of
the users of the API.

Let's also clarify what the <0 return value means in API docs.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-02-25 17:16:31 -08:00
Junio C Hamano 061a21d36d Merge branch 'ab/fsck-unexpected-type'
"git fsck" has been taught to report mismatch between expected and
actual types of an object better.

* ab/fsck-unexpected-type:
  fsck: report invalid object type-path combinations
  fsck: don't hard die on invalid object types
  object-file.c: stop dying in parse_loose_header()
  object-file.c: return ULHR_TOO_LONG on "header too long"
  object-file.c: use "enum" return type for unpack_loose_header()
  object-file.c: simplify unpack_loose_short_header()
  object-file.c: make parse_loose_header_extended() public
  object-file.c: return -1, not "status" from unpack_loose_header()
  object-file.c: don't set "typep" when returning non-zero
  cat-file tests: test for current --allow-unknown-type behavior
  cat-file tests: add corrupt loose object test
  cat-file tests: test for missing/bogus object with -t, -s and -p
  cat-file tests: move bogus_* variable declarations earlier
  fsck tests: test for garbage appended to a loose object
  fsck tests: test current hash/type mismatch behavior
  fsck tests: refactor one test to use a sub-repo
  fsck tests: add test for fsck-ing an unknown type
2021-10-25 16:06:56 -07:00
Ævar Arnfjörð Bjarmason 96e41f58fe fsck: report invalid object type-path combinations
Improve the error that's emitted in cases where we find a loose object
we parse, but which isn't at the location we expect it to be.

Before this change we'd prefix the error with a not-a-OID derived from
the path at which the object was found, due to an emergent behavior in
how we'd end up with an "OID" in these codepaths.

Now we'll instead say what object we hashed, and what path it was
found at. Before this patch series e.g.:

    $ git hash-object --stdin -w -t blob </dev/null
    e69de29bb2
    $ mv objects/e6/ objects/e7

Would emit ("[...]" used to abbreviate the OIDs):

    git fsck
    error: hash mismatch for ./objects/e7/9d[...] (expected e79d[...])
    error: e79d[...]: object corrupt or missing: ./objects/e7/9d[...]

Now we'll instead emit:

    error: e69d[...]: hash-path mismatch, found at: ./objects/e7/9d[...]

Furthermore, we'll do the right thing when the object type and its
location are bad. I.e. this case:

    $ git hash-object --stdin -w -t garbage --literally </dev/null
    8315a83d2acc4c174aed59430f9a9c4ed926440f
    $ mv objects/83 objects/84

As noted in an earlier commits we'd simply die early in those cases,
until preceding commits fixed the hard die on invalid object type:

    $ git fsck
    fatal: invalid object type

Now we'll instead emit sensible error messages:

    $ git fsck
    error: 8315[...]: hash-path mismatch, found at: ./objects/84/15[...]
    error: 8315[...]: object is of unknown type 'garbage': ./objects/84/15[...]

In both fsck.c and object-file.c we're using null_oid as a sentinel
value for checking whether we got far enough to be certain that the
issue was indeed this OID mismatch.

We need to add the "object corrupt or missing" special-case to deal
with cases where read_loose_object() will return an error before
completing check_object_signature(), e.g. if we have an error in
unpack_loose_rest() because we find garbage after the valid gzip
content:

    $ git hash-object --stdin -w -t blob </dev/null
    e69de29bb2
    $ chmod 755 objects/e6/9de29bb2d1d6434b8b29ae775ad8c2e48c5391
    $ echo garbage >>objects/e6/9de29bb2d1d6434b8b29ae775ad8c2e48c5391
    $ git fsck
    error: garbage at end of loose object 'e69d[...]'
    error: unable to unpack contents of ./objects/e6/9d[...]
    error: e69d[...]: object corrupt or missing: ./objects/e6/9d[...]

There is currently some weird messaging in the edge case when the two
are combined, i.e. because we're not explicitly passing along an error
state about this specific scenario from check_stream_oid() via
read_loose_object() we'll end up printing the null OID if an object is
of an unknown type *and* it can't be unpacked by zlib, e.g.:

    $ git hash-object --stdin -w -t garbage --literally </dev/null
    8315a83d2acc4c174aed59430f9a9c4ed926440f
    $ chmod 755 objects/83/15a83d2acc4c174aed59430f9a9c4ed926440f
    $ echo garbage >>objects/83/15a83d2acc4c174aed59430f9a9c4ed926440f
    $ /usr/bin/git fsck
    fatal: invalid object type
    $ ~/g/git/git fsck
    error: garbage at end of loose object '8315a83d2acc4c174aed59430f9a9c4ed926440f'
    error: unable to unpack contents of ./objects/83/15a83d2acc4c174aed59430f9a9c4ed926440f
    error: 8315a83d2acc4c174aed59430f9a9c4ed926440f: object corrupt or missing: ./objects/83/15a83d2acc4c174aed59430f9a9c4ed926440f
    error: 0000000000000000000000000000000000000000: object is of unknown type 'garbage': ./objects/83/15a83d2acc4c174aed59430f9a9c4ed926440f
    [...]

I think it's OK to leave that for future improvements, which would
involve enum-ifying more error state as we've done with "enum
unpack_loose_header_result" in preceding commits. In these
increasingly more obscure cases the worst that can happen is that
we'll get slightly nonsensical or inapplicable error messages.

There's other such potential edge cases, all of which might produce
some confusing messaging, but still be handled correctly as far as
passing along errors goes. E.g. if check_object_signature() returns
and oideq(real_oid, null_oid()) is true, which could happen if it
returns -1 due to the read_istream() call having failed.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-10-01 15:06:01 -07:00
Taylor Blau f9221e2cf5 csum-file: introduce checksum_valid()
Introduce a new function which checks the validity of a file's trailing
checksum. This is similar to hashfd_check(), but different since it is
intended to be used by callers who aren't writing the same data (like
`git index-pack --verify`), but who instead want to validate the
integrity of data that they are reading.

Rewrite the first of two callers which could benefit from this new
function in pack-check.c. Subsequent callers will be added in the
following patches.

Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-06-28 20:36:17 -07:00
Jeff King 33bbc59fed fsck: correctly compute checksums on idx files larger than 4GB
When checking the trailing checksum hash of a .idx file, we pass the
whole buffer (minus the trailing hash) into a single call to
the_hash_algo->update_fn(). But we cast it to an "unsigned int". This
comes from c4001d92be (Use off_t when we really mean a file offset.,
2007-03-06). That commit started storing the index_size variable as an
off_t, but our mozilla-sha1 implementation from the time was limited to
a smaller size. Presumably the cast was a way of annotating that we
expected .idx files to be small, and so we didn't need to loop (as we do
for arbitrarily-large .pack files). Though as an aside it was still
wrong, because the mozilla function actually took a signed int.

These days our hash-update functions are defined to take a size_t, so we
can pass the whole buffer in directly. The cast is actually causing a
buggy truncation!

While we're here, though, let's drop the confusing off_t variable in the
first place. We're getting the size not from the filesystem anyway, but
from p->index_size, which is a size_t. In fact, we can make the code a
bit more readable by dropping our local variable duplicating
p->index_size, and instead have one that stores the size of the actual
index data, minus the trailing hash.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-16 13:41:35 -08:00
Jeff King f86f769550 compute pack .idx byte offsets using size_t
A pack and its matching .idx file are limited to 2^32 objects, because
the pack format contains a 32-bit field to store the number of objects.
Hence we use uint32_t in the code.

But the byte count of even a .idx file can be much larger than that,
because it stores at least a hash and an offset for each object. So
using SHA-1, a v2 .idx file will cross the 4GB boundary at 153,391,650
objects. This confuses load_idx(), which computes the minimum size like
this:

  unsigned long min_size = 8 + 4*256 + nr*(hashsz + 4 + 4) + hashsz + hashsz;

Even though min_size will be big enough on most 64-bit platforms, the
actual arithmetic is done as a uint32_t, resulting in a truncation. We
actually exceed that min_size, but then we do:

  unsigned long max_size = min_size;
  if (nr)
          max_size += (nr - 1)*8;

to account for the variable-sized table. That computation doesn't
overflow quite so low, but with the truncation for min_size, we end up
with a max_size that is much smaller than our actual size. So we
complain that the idx is invalid, and can't find any of its objects.

We can fix this case by casting "nr" to a size_t, which will do the
multiplication in 64-bits (assuming you're on a 64-bit platform; this
will never work on a 32-bit system since we couldn't map the whole .idx
anyway). Likewise, we don't have to worry about further additions,
because adding a smaller number to a size_t will convert the other side
to a size_t.

A few notes:

  - obviously we could just declare "nr" as a size_t in the first place
    (and likewise, packed_git.num_objects).  But it's conceptually a
    uint32_t because of the on-disk format, and we correctly treat it
    that way in other contexts that don't need to compute byte offsets
    (e.g., iterating over the set of objects should and generally does
    use a uint32_t). Switching to size_t would make all of those other
    cases look wrong.

  - it could be argued that the proper type is off_t to represent the
    file offset. But in practice the .idx file must fit within memory,
    because we mmap the whole thing. And the rest of the code (including
    the idx_size variable we're comparing against) uses size_t.

  - we'll add the same cast to the max_size arithmetic line. Even though
    we're adding to a larger type, which will convert our result, the
    multiplication is still done as a 32-bit value and can itself
    overflow. I didn't check this with my test case, since it would need
    an even larger pack (~530M objects), but looking at compiler output
    shows that it works this way. The standard should agree, but I
    couldn't find anything explicit in 6.3.1.8 ("usual arithmetic
    conversions").

The case in load_idx() was the most immediate one that I was able to
trigger. After fixing it, looking up actual objects (including the very
last one in sha1 order) works in a test repo with 153,725,110 objects.
That's because bsearch_hash() works with uint32_t entry indices, and the
actual byte access:

  int cmp = hashcmp(table + mi * stride, sha1);

is done with "stride" as a size_t, causing the uint32_t "mi" to be
promoted to a size_t. This is the way most code will access the index
data.

However, I audited all of the other byte-wise accesses of
packed_git.index_data, and many of the others are suspect (they are
similar to the max_size one, where we are adding to a properly sized
offset or directly to a pointer, but the multiplication in the
sub-expression can overflow). I didn't trigger any of these in practice,
but I believe they're potential problems, and certainly adding in the
cast is not going to hurt anything here.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-16 13:41:35 -08:00
Jeff King 63f4a7fc01 pack-check: push oid lookup into loop
When we're checking a pack with fsck or verify-pack, we first sort the
idx entries by offset, since accessing them in pack order is more
efficient. To do so, we loop over them and fill in an array of structs
with the offset, object_id, and index position of each, sort the result,
and only then do we iterate over the sorted array and process each
entry.

In order to avoid the memory cost of storing the hash of each object, we
just store a pointer into the copy in the mmap'd pack index file. To
keep that property even as the rest of the code converted to "struct
object_id", commit 9fd750461b (Convert the verify_pack callback to
struct object_id, 2017-05-06) introduced a union in order to type-pun
the pointer-to-hash into an object_id struct.

But we can make this even simpler by observing that the sort operation
doesn't need the object id at all! We only need them one at a time while
we actually process each entry. So we can just omit the oid from the
struct entirely and load it on the fly into a local variable in the
second loop.

This gets rid of the type-punning, and lets us directly use the more
type-safe nth_packed_object_id(), simplifying the code. And as a bonus,
it saves 8 bytes of memory per object.

Note that this does mean we'll do the offset lookup for each object
before the oid lookup. The oid lookup has more safety checks in it
(e.g., for looking past p->num_objects) which in theory protected the
offset lookup. But since violating those checks was already a BUG()
condition (as described in the previous commit), it's not worth worrying
about.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-24 12:55:53 -08:00
Jeff King e31c71083a pack-check: convert "internal error" die to a BUG()
If we fail to load the oid from the index of a packfile, we'll die()
with an "internal error". But this should never happen: we'd fail here
only if the idx needed to be lazily opened (but we've already opened it)
or if we asked for an out-of-range index (but we're iterating using the
same count that we'd check the range against). A corrupted index might
have a bogus count (e.g., too large for its size), but we'd have
complained and aborted already when opening the index initially.

While we're here, we can add a few details so that if this bug ever
_does_ trigger, we'll have a bit more information.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-24 12:55:53 -08:00
Matheus Tavares b98d188581 sha1-file: allow check_object_signature() to handle any repo
Some callers of check_object_signature() can work on arbitrary
repositories, but the repo does not get passed to this function.
Instead, the_repository is always used internally. To fix possible
inconsistencies, allow the function to receive a struct repository and
make those callers pass on the repo being handled.

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-31 10:45:39 -08:00
Matheus Tavares 5ec9b8accd pack-check: use given repo's hash_algo at verify_packfile()
At verify_packfile(), use the git_hash_algo from the provided repository
instead of the_hash_algo, for consistency. Like the previous patch, this
shouldn't bring any behavior changes, since this function is currently
only receiving the_repository.

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-31 10:45:39 -08:00
Nguyễn Thái Ngọc Duy 94e10825bd pack-check.c: remove the_repository references
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-12 14:50:06 +09:00
Jeff King 67947c34ae convert "hashcmp() != 0" to "!hasheq()"
This rounds out the previous three patches, covering the
inequality logic for the "hash" variant of the functions.

As with the previous three, the accompanying code changes
are the mechanical result of applying the coccinelle patch;
see those patches for more discussion.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-29 11:32:49 -07:00
Stefan Beller 57a6a500be packfile: add repository argument to unpack_entry
Add a repository argument to allow the callers of unpack_entry
to be more specific about which repository to act on. This is a small
mechanical change; it doesn't change the implementation to handle
repositories other than the_repository yet.

As with the previous commits, use a macro to catch callers passing a
repository other than the_repository at compile time.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-26 10:54:27 +09:00
Junio C Hamano cf0b1793ea Merge branch 'sb/object-store'
Refactoring the internal global data structure to make it possible
to open multiple repositories, work with and then close them.

Rerolled by Duy on top of a separate preliminary clean-up topic.
The resulting structure of the topics looked very sensible.

* sb/object-store: (27 commits)
  sha1_file: allow sha1_loose_object_info to handle arbitrary repositories
  sha1_file: allow map_sha1_file to handle arbitrary repositories
  sha1_file: allow map_sha1_file_1 to handle arbitrary repositories
  sha1_file: allow open_sha1_file to handle arbitrary repositories
  sha1_file: allow stat_sha1_file to handle arbitrary repositories
  sha1_file: allow sha1_file_name to handle arbitrary repositories
  sha1_file: add repository argument to sha1_loose_object_info
  sha1_file: add repository argument to map_sha1_file
  sha1_file: add repository argument to map_sha1_file_1
  sha1_file: add repository argument to open_sha1_file
  sha1_file: add repository argument to stat_sha1_file
  sha1_file: add repository argument to sha1_file_name
  sha1_file: allow prepare_alt_odb to handle arbitrary repositories
  sha1_file: allow link_alt_odb_entries to handle arbitrary repositories
  sha1_file: add repository argument to prepare_alt_odb
  sha1_file: add repository argument to link_alt_odb_entries
  sha1_file: add repository argument to read_info_alternates
  sha1_file: add repository argument to link_alt_odb_entry
  sha1_file: add raw_object_store argument to alt_odb_usable
  pack: move approximate object count to object store
  ...
2018-04-11 13:09:55 +09:00
Stefan Beller a80d72db2a object-store: move packed_git and packed_git_mru to object store
In a process with multiple repositories open, packfile accessors
should be associated to a single repository and not shared globally.
Move packed_git and packed_git_mru into the_repository and adjust
callers to reflect this.

[nd: while at there, wrap access to these two fields in get_packed_git()
and get_packed_git_mru(). This allows us to lazily initialize these
fields without caller doing that explicitly]

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-03-26 10:05:46 -07:00
brian m. carlson 17e65451e3 sha1_file: convert check_sha1_signature to struct object_id
Convert this function to take a pointer to struct object_id and rename
it check_object_signature.  Introduce temporaries to convert the return
values of lookup_replace_object and lookup_replace_object_extended into
struct object_id.

The temporaries are needed because in order to convert
lookup_replace_object, open_istream needs to be converted, and
open_istream needs check_sha1_signature to be converted, causing a loop
of dependencies.  The temporaries will be removed in a future patch.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-03-14 09:23:49 -07:00
Junio C Hamano 169c9c0169 Merge branch 'bw/c-plus-plus'
Avoid using identifiers that clash with C++ keywords.  Even though
it is not a goal to compile Git with C++ compilers, changes like
this help use of code analysis tools that targets C++ on our
codebase.

* bw/c-plus-plus: (37 commits)
  replace: rename 'new' variables
  trailer: rename 'template' variables
  tempfile: rename 'template' variables
  wrapper: rename 'template' variables
  environment: rename 'namespace' variables
  diff: rename 'template' variables
  environment: rename 'template' variables
  init-db: rename 'template' variables
  unpack-trees: rename 'new' variables
  trailer: rename 'new' variables
  submodule: rename 'new' variables
  split-index: rename 'new' variables
  remote: rename 'new' variables
  ref-filter: rename 'new' variables
  read-cache: rename 'new' variables
  line-log: rename 'new' variables
  imap-send: rename 'new' variables
  http: rename 'new' variables
  entry: rename 'new' variables
  diffcore-delta: rename 'new' variables
  ...
2018-03-06 14:54:07 -08:00
Brandon Williams debca9d2fe object: rename function 'typename' to 'type_name'
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>
2018-02-14 13:10:05 -08:00
brian m. carlson ccc12e0676 pack-check: convert various uses of SHA-1 to abstract forms
Convert various explicit calls to use SHA-1 functions and constants to
references to the_hash_algo.  Make several strings more generic with
respect to the hash algorithm used.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-02-02 11:28:41 -08:00
Jonathan Tan 0317f45576 pack: move open_pack_index(), parse_pack_index()
alloc_packed_git() in packfile.c is duplicated from sha1_file.c. In a
subsequent commit, alloc_packed_git() will be removed from sha1_file.c.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-23 15:12:06 -07:00
brian m. carlson 9fd750461b Convert the verify_pack callback to struct object_id
Make the verify_pack_callback take a pointer to struct object_id.
Change the pack checksum to use GIT_MAX_RAWSZ, even though it is not
strictly an object ID.  Doing so ensures resilience against future hash
size changes, and allows us to remove hard-coded assumptions about how
big the buffer needs to be.

Also, use a union to convert the pointer from nth_packed_object_sha1 to
to a pointer to struct object_id.  This behavior is compatible with GCC
and clang and explicitly sanctioned by C11.  The alternatives are to
just perform a cast, which would run afoul of strict aliasing rules, but
should just work, and changing the pointer into an instance of struct
object_id and copying the value.  The latter operation could seriously
bloat memory usage on fsck, which already uses a lot of memory on some
repositories.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-08 15:12:57 +09:00
Junio C Hamano b8688adb12 Merge branch 'rs/qsort'
We call "qsort(array, nelem, sizeof(array[0]), fn)", and most of
the time third parameter is redundant.  A new QSORT() macro lets us
omit it.

* rs/qsort:
  show-branch: use QSORT
  use QSORT, part 2
  coccicheck: use --all-includes by default
  remove unnecessary check before QSORT
  use QSORT
  add QSORT
2016-10-10 14:03:46 -07:00
Junio C Hamano 5c2c2d4aee Merge branch 'jk/verify-packfile-gently'
A low-level function verify_packfile() was meant to show errors
that were detected without dying itself, but under some conditions
it didn't and died instead, which has been fixed.

* jk/verify-packfile-gently:
  verify_packfile: check pack validity before accessing data
2016-09-29 16:57:13 -07:00
René Scharfe 9ed0d8d6e6 use QSORT
Apply the semantic patch contrib/coccinelle/qsort.cocci to the code
base, replacing calls of qsort(3) with QSORT.  The resulting code is
shorter and supports empty arrays with NULL pointers.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-29 15:42:18 -07:00
Jeff King a9445d859e verify_packfile: check pack validity before accessing data
The verify_packfile() does not explicitly open the packfile;
instead, it starts with a sha1 checksum over the whole pack,
and relies on use_pack() to open the packfile as a side
effect.

If the pack cannot be opened for whatever reason (either
because its header information is corrupted, or perhaps
because a simultaneous repack deleted it), then use_pack()
will die(), as it has no way to return an error. This is not
ideal, as verify_packfile() otherwise tries to gently return
an error (this lets programs like git-fsck go on to check
other packs).

Instead, let's check is_pack_valid() up front, and return an
error if it fails. This will open the pack as a side effect,
and then use_pack() will later rely on our cached
descriptor, and avoid calling die().

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-09-22 11:18:13 -07:00
Nguyễn Thái Ngọc Duy ec9d224903 fsck: use streaming interface for large blobs in pack
For blobs, we want to make sure the on-disk data is not corrupted
(i.e. can be inflated and produce the expected SHA-1). Blob content is
opaque, there's nothing else inside to check for.

For really large blobs, we may want to avoid unpacking the entire blob
in memory, just to check whether it produces the same SHA-1. On 32-bit
systems, we may not have enough virtual address space for such memory
allocation. And even on 64-bit where it's not a problem, allocating a
lot more memory could result in kicking other parts of systems to swap
file, generating lots of I/O and slowing everything down.

For this particular operation, not unpacking the blob and letting
check_sha1_signature, which supports streaming interface, do the job
is sufficient. check_sha1_signature() is not shown in the diff,
unfortunately. But if will be called when "data_valid && !data" is
false.

We will call the callback function "fn" with NULL as "data". The only
callback of this function is fsck_obj_buffer(), which does not touch
"data" at all if it's a blob.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-07-13 09:15:29 -07:00
Jeff King b32fa95fd8 convert trivial cases to ALLOC_ARRAY
Each of these cases can be converted to use ALLOC_ARRAY or
REALLOC_ARRAY, which has two advantages:

  1. It automatically checks the array-size multiplication
     for overflow.

  2. It always uses sizeof(*array) for the element-size,
     so that it can never go out of sync with the declared
     type of the array.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-02-22 14:51:09 -08:00
David Turner 8c24d832cd verify_pack: do not ignore return value of verification function
In verify_pack, a caller-supplied verification function is called.
The function returns an int.  If that return value is non-zero,
verify_pack should fail.

The only caller of verify_pack is in builtin/fsck.c, whose verify_fn
returns a meaningful error code (which was then ignored).  Now, fsck
might return a different error code (with more detail).  This would
happen in the unlikely event that a commit or tree that is a valid git
object but not a valid instance of its type gets into a pack.

Signed-off-by: David Turner <dturner@twopensource.com>
Signed-off-by: Jeff King <peff@peff.net>
2015-12-01 18:19:35 -05:00
Nguyễn Thái Ngọc Duy 1e49f22f07 fsck: print progress
fsck is usually a long process and it would be nice if it prints
progress from time to time.

Progress meter is not printed when --verbose is given because
--verbose prints a lot, there's no need for "alive" indicator.
Progress meter may provide "% complete" information but it would
be lost anyway in the flood of text.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-11-06 20:31:28 -08:00
Nguyễn Thái Ngọc Duy c9486eb04d fsck: avoid reading every object twice
During verify_pack() all objects are read for SHA-1 check. Then
fsck_sha1() is called on every object, which read the object again
(fsck_sha1 -> parse_object -> read_sha1_file).

Avoid reading an object twice, do fsck_sha1 while we have an object
uncompressed data in verify_pack.

On git.git, with this patch I got:

$ /usr/bin/time ./git fsck >/dev/null
98.97user 0.90system 1:40.01elapsed 99%CPU (0avgtext+0avgdata 616624maxresident)k
0inputs+0outputs (0major+194186minor)pagefaults 0swaps

Without it:

$ /usr/bin/time ./git fsck >/dev/null
231.23user 2.35system 3:53.82elapsed 99%CPU (0avgtext+0avgdata 636688maxresident)k
0inputs+0outputs (0major+461629minor)pagefaults 0swaps

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-11-06 20:31:28 -08:00
Nguyễn Thái Ngọc Duy 473935188c verify_packfile(): check as many object as possible in a pack
verify_packfile() checks for whole pack integerity first, then each
object individually. Once we get past whole pack check, we can
identify all objects in the pack. If there's an error with one object,
we should continue to check the next objects to salvage as many
objects as possible instead of stopping the process.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-11-06 20:31:28 -08:00
Junio C Hamano ef49a7a012 zlib: zlib can only process 4GB at a time
The size of objects we read from the repository and data we try to put
into the repository are represented in "unsigned long", so that on larger
architectures we can handle objects that weigh more than 4GB.

But the interface defined in zlib.h to communicate with inflate/deflate
limits avail_in (how many bytes of input are we calling zlib with) and
avail_out (how many bytes of output from zlib are we ready to accept)
fields effectively to 4GB by defining their type to be uInt.

In many places in our code, we allocate a large buffer (e.g. mmap'ing a
large loose object file) and tell zlib its size by assigning the size to
avail_in field of the stream, but that will truncate the high octets of
the real size. The worst part of this story is that we often pass around
z_stream (the state object used by zlib) to keep track of the number of
used bytes in input/output buffer by inspecting these two fields, which
practically limits our callchain to the same 4GB limit.

Wrap z_stream in another structure git_zstream that can express avail_in
and avail_out in unsigned long. For now, just die() when the caller gives
a size that cannot be given to a single zlib call. In later patches in the
series, we would make git_inflate() and git_deflate() internally loop to
give callers an illusion that our "improved" version of zlib interface can
operate on a buffer larger than 4GB in one go.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-06-10 11:52:15 -07:00
Stephen Boyd 1e4cd68c00 sparse: Fix errors and silence warnings
* load_file() returns a void pointer but is using 0 for the return
   value

 * builtin/receive-pack.c forgot to include builtin.h

 * packet_trace_prefix can be marked static

 * ll_merge takes a pointer for its last argument, not an int

 * crc32 expects a pointer as the second argument but Z_NULL is defined
   to be 0 (see 38f4d13 sparse fix: Using plain integer as NULL pointer,
   2006-11-18 for more info)

Signed-off-by: Stephen Boyd <bebarino@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-04-03 10:14:53 -07:00
Jonathan Nieder 9cba13ca5d standardize brace placement in struct definitions
In a struct definitions, unlike functions, the prevailing style is for
the opening brace to go on the same line as the struct name, like so:

 struct foo {
	int bar;
	char *baz;
 };

Indeed, grepping for 'struct [a-z_]* {$' yields about 5 times as many
matches as 'struct [a-z_]*$'.

Linus sayeth:

 Heretic people all over the world have claimed that this inconsistency
 is ...  well ...  inconsistent, but all right-thinking people know that
 (a) K&R are _right_ and (b) K&R are right.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-03-16 12:49:02 -07:00
Ralf Wildenhues 22e5e58a3c Typos in code comments, an error message, documentation
Signed-off-by: Ralf Wildenhues <Ralf.Wildenhues@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-08-22 13:25:08 -07:00
Shawn O. Pearce 9b0aa72870 Extract verify_pack_index for reuse from verify_pack
The dumb HTTP transport should verify an index is completely valid
before trying to use it.  That requires checking the header/footer
but also checking the complete content SHA-1.  All of this logic is
already in the front half of verify_pack, so pull it out into a new
function that can be reused.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-04-19 17:56:13 -07:00
Mike Hommey 4277c6709d Don't expect verify_pack() callers to set pack_size
Since use_pack() will end up populating pack_size if it is not already set,
we can just adapt the code in verify_packfile() such that it doesn't require
pack_size to be set beforehand.

This allows callers not to have to set pack_size themselves, and we can thus
revert changes from 1c23d794 (Don't die in git-http-fetch when fetching packs).

Signed-off-by: Mike Hommey <mh@glandium.org>
Signed-off-by: Tay Ray Chuan <rctay89@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-06-06 10:56:27 -07:00
Nicolas Pitre 9126f0091f fix openssl headers conflicting with custom SHA1 implementations
On ARM I have the following compilation errors:

    CC fast-import.o
In file included from cache.h:8,
                 from builtin.h:6,
                 from fast-import.c:142:
arm/sha1.h:14: error: conflicting types for 'SHA_CTX'
/usr/include/openssl/sha.h:105: error: previous declaration of 'SHA_CTX' was here
arm/sha1.h:16: error: conflicting types for 'SHA1_Init'
/usr/include/openssl/sha.h:115: error: previous declaration of 'SHA1_Init' was here
arm/sha1.h:17: error: conflicting types for 'SHA1_Update'
/usr/include/openssl/sha.h:116: error: previous declaration of 'SHA1_Update' was here
arm/sha1.h:18: error: conflicting types for 'SHA1_Final'
/usr/include/openssl/sha.h:117: error: previous declaration of 'SHA1_Final' was here
make: *** [fast-import.o] Error 1

This is because openssl header files are always included in
git-compat-util.h since commit 684ec6c63c whenever NO_OPENSSL is not
set, which somehow brings in <openssl/sha1.h> clashing with the custom
ARM version.  Compilation of git is probably broken on PPC too for the
same reason.

Turns out that the only file requiring openssl/ssl.h and openssl/err.h
is imap-send.c.  But only moving those problematic includes there
doesn't solve the issue as it also includes cache.h which brings in the
conflicting local SHA1 header file.

As suggested by Jeff King, the best solution is to rename our references
to SHA1 functions and structure to something git specific, and define those
according to the implementation used.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
2008-10-02 18:06:56 -07:00
Nicolas Pitre c41a4a9468 verify-pack: check packed object CRC when using index version 2
To do so, check_pack_crc() moved from builtin-pack-objects.c to
pack-check.c where it is more logical to share.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-06-24 23:58:57 -07:00
Nicolas Pitre 77d3ecee85 move show_pack_info() where it belongs
This is called when verify_pack() has its verbose argument set, and
verbose in this context makes sense only for the actual 'git verify-pack'
command.  Therefore let's move show_pack_info() to builtin-verify-pack.c
instead and remove useless verbose argument from verify_pack().

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-06-24 23:58:57 -07:00
Nicolas Pitre 99093238bb optimize verify-pack a bit
Using find_pack_entry_one() to get object offsets is rather suboptimal
when nth_packed_object_offset() can be used directly.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-06-24 23:58:57 -07:00
Nicolas Pitre 1f5c74f6cf call init_pack_revindex() lazily
This makes life much easier for next patch, as well as being more efficient
when the revindex is actually not used.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-06-23 21:25:20 -07:00
Nicolas Pitre 6241360498 make verify-pack a bit more useful with bad packs
When a pack gets corrupted, its SHA1 checksum will fail.  However, this
is more useful to let the test go on in order to find the actual
problem location than only complain about the SHA1 mismatch and
bail out.

Also, it is more useful to compare the stored pack SHA1 with the one in
the index file instead of the computed SHA1 since the computed SHA1
from a corrupted pack won't match the one stored in the index either.

Finally a few code and message cleanups were thrown in as a bonus.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-06-01 23:25:38 -07:00
Nicolas Pitre 5f4347bba3 add storage size output to 'git verify-pack -v'
This can possibly break external scripts that depend on the previous
output, but those script can't possibly be critical to Git usage, and
fixing them should be trivial.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-03-01 01:44:46 -08:00
Nicolas Pitre 70f5d5d31c fix unimplemented packed_object_info_detail() features
Since commit eb32d236df, there was a TODO
comment in packed_object_info_detail() about the SHA1 of base object to
OBJ_OFS_DELTA objects.  So here it is at last.

While at it, providing the actual storage size information as well is now
trivial.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-03-01 01:44:46 -08:00
Alexandre Julliard 3af51928ab pack-check: Sort entries by pack offset before unpacking them.
Because of the way objects are sorted in a pack, unpacking them in
disk order is much more efficient than random access. Tests on the
Wine repository show a gain in pack validation time of about 35%.

Signed-off-by: Alexandre Julliard <julliard@winehq.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-06-06 16:04:02 -07:00
Shawn O. Pearce d079837eee Lazily open pack index files on demand
In some repository configurations the user may have many packfiles,
but all of the recent commits/trees/tags/blobs are likely to
be in the most recent packfile (the one with the newest mtime).
It is therefore common to be able to complete an entire operation
by accessing only one packfile, even if there are 25 packfiles
available to the repository.

Rather than opening and mmaping the corresponding .idx file for
every pack found, we now only open and map the .idx when we suspect
there might be an object of interest in there.

Of course we cannot known in advance which packfile contains an
object, so we still need to scan the entire packed_git list to
locate anything.  But odds are users want to access objects in the
most recently created packfiles first, and that may be all they
ever need for the current operation.

Junio observed in b867092f that placing recent packfiles before
older ones can slightly improve access times for recent objects,
without degrading it for historical object access.

This change improves upon Junio's observations by trying even harder
to avoid the .idx files that we won't need.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-05-26 20:28:08 -07:00
Nicolas Pitre ddcf786fd7 fixes to output of git-verify-pack -v
Now that the default delta depth is 50, it is a good idea to also bump
MAX_CHAIN to 50.

While at it, make the display a bit prettier by making the MAX_CHAIN
limit inclusive, and display the number of deltas that are above that
limit at the end instead of the beginning.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-05-25 21:42:47 -07:00