Commit Graph

62 Commits

Author SHA1 Message Date
Junio C Hamano
6ee353d42f Merge branch 'jt/transfer-fsck-across-packs'
The approach to "fsck" the incoming objects in "index-pack" is
attractive for performance reasons (we have them already in core,
inflated and ready to be inspected), but fundamentally cannot be
applied fully when we receive more than one pack stream, as a tree
object in one pack may refer to a blob object in another pack as
".gitmodules", when we want to inspect blobs that are used as
".gitmodules" file, for example.  Teach "index-pack" to emit
objects that must be inspected later and check them in the calling
"fetch-pack" process.

* jt/transfer-fsck-across-packs:
  fetch-pack: print and use dangling .gitmodules
  fetch-pack: with packfile URIs, use index-pack arg
  http-fetch: allow custom index-pack args
  http: allow custom index-pack args
2021-03-01 14:02:57 -08:00
Jonathan Tan
5476e1efde fetch-pack: print and use dangling .gitmodules
Teach index-pack to print dangling .gitmodules links after its "keep" or
"pack" line instead of declaring an error, and teach fetch-pack to check
such lines printed.

This allows the tree side of the .gitmodules link to be in one packfile
and the blob side to be in another without failing the fsck check,
because it is now fetch-pack which checks such objects after all
packfiles have been downloaded and indexed (and not index-pack on an
individual packfile, as it is before this commit).

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-22 12:07:40 -08:00
Taylor Blau
8ef50d9958 pack-write.c: prepare to write 'pack-*.rev' files
This patch prepares for callers to be able to write reverse index files
to disk.

It adds the necessary machinery to write a format-compliant .rev file
from within 'write_rev_file()', which is called from
'finish_tmp_packfile()'.

Similar to the process by which the reverse index is computed in memory,
these new paths also have to sort a list of objects by their offsets
within a packfile. These new paths use a qsort() (as opposed to a radix
sort), since our specialized radix sort requires a full revindex_entry
struct per object, which is more memory than we need to allocate.

The qsort is obviously slower, but the theoretical slowdown would
require a repository with a large amount of objects, likely implying
that the time spent in, say, pack-objects during a repack would dominate
the overall runtime.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-25 18:32:43 -08:00
Christian Couder
7c99bc23fc pack-write: die on error in write_promisor_file()
write_promisor_file() already uses xfopen(), so it would die
if the file cannot be opened for writing. To be consistent
with this behavior and not overlook issues, let's also die if
there are errors when we are actually writing to the file.

Suggested-by: Jeff King <peff@peff.net>
Suggested-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-14 17:02:22 -08:00
Christian Couder
33add2ad7d fetch-pack: refactor writing promisor file
Let's replace the 2 different pieces of code that write a
promisor file in 'builtin/repack.c' and 'fetch-pack.c'
with a new function called 'write_promisor_file()' in
'pack-write.c' and 'pack.h'.

This might also help us in the future, if we want to put
back the ref names and associated hashes that were in
the promisor files we are repacking in 'builtin/repack.c'
as suggested by a NEEDSWORK comment just above the code
we are refactoring.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-12 16:01:07 -08:00
Junio C Hamano
455e8d18f8 Merge branch 'rs/hashwrite-be64'
Code simplification.

* rs/hashwrite-be64:
  pack-write: use hashwrite_be64()
  midx: use hashwrite_be64()
  csum-file: add hashwrite_be64()
2020-11-25 15:24:52 -08:00
René Scharfe
970909c2a7 pack-write: use hashwrite_be64()
Call hashwrite_be64() to write a 64-bit value instead of open-coding it
using htonl() and hashwrite().  This shortens the code, gets rid of a
buffer and several magic numbers, and makes the intent clearer.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-12 09:40:10 -08:00
René Scharfe
06d43fad18 pack-write: use hashwrite_be32() instead of double-buffering array
hashwrite() already buffers writes, so pass the fanout table entries
individually via hashwrite_be32(), which also does the endianess
conversion for us.  This avoids a memory copy, shortens the code and
reduces the number of magic numbers.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-01 15:52:51 -08:00
René Scharfe
389cf68caf pack-write: use hashwrite_be32() in write_idx_file()
Call hashwrite_be32() instead of open-coding it.  This shortens the code
a bit and makes it easier to read.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-19 12:15:36 -07:00
Junio C Hamano
d61aed07bd Merge branch 'jb/doc-packfile-name' into master
Doc update.

* jb/doc-packfile-name:
  pack-write/docs: update regarding pack naming
2020-07-30 21:34:32 -07:00
Johannes Berg
e2bfa50ac3 pack-write/docs: update regarding pack naming
The index-pack documentation explicitly states that the pack
name is derived from the sorted list of object names, but
since commit 1190a1acf8 ("pack-objects: name pack files
after trailer hash") that isn't true anymore.

Be less explicit in the docs as to what the exact output is,
and just say that it's whatever goes into the pack name.

Also update a comment on write_idx_file() since it no longer
modifies the sha1 variable (it's const now anyway), as noted
by Junio.

Fixes: 1190a1acf8 ("pack-objects: name pack files after trailer hash")
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-22 15:38:22 -07:00
brian m. carlson
894c0f66bb pack-write: use hash_to_hex when writing checksums
Pack checksums always use the current hash algorithm in use, so switch
from sha1_to_hex to hash_to_hex.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-08-19 15:04:58 -07:00
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
Jeff King
4a7e27e957 convert "oidcmp() == 0" to oideq()
Using the more restrictive oideq() should, in the long run,
give the compiler more opportunities to optimize these
callsites. For now, this conversion should be a complete
noop with respect to the generated code.

The result is also perhaps a little more readable, as it
avoids the "zero is equal" idiom. Since it's so prevalent in
C, I think seasoned programmers tend not to even notice it
anymore, but it can sometimes make for awkward double
negations (e.g., we can drop a few !!oidcmp() instances
here).

This patch was generated almost entirely by the included
coccinelle patch. This mechanical conversion should be
completely safe, because we check explicitly for cases where
oidcmp() is compared to 0, which is what oideq() is doing
under the hood. Note that we don't have to catch "!oidcmp()"
separately; coccinelle's standard isomorphisms make sure the
two are treated equivalently.

I say "almost" because I did hand-edit the coccinelle output
to fix up a few style violations (it mostly keeps the
original formatting, but sometimes unwraps long lines).

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
Derrick Stolee
cfe83216e4 csum-file: refactor finalize_hashfile() method
If we want to use a hashfile on the temporary file for a lockfile, then
we need finalize_hashfile() to fully write the trailing hash but also keep
the file descriptor open.

Do this by adding a new CSUM_HASH_IN_STREAM flag along with a functional
change that checks this flag before writing the checksum to the stream.
This differs from previous behavior since it would be written if either
CSUM_CLOSE or CSUM_FSYNC is provided.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-02 14:27:30 -07:00
Derrick Stolee
f2af9f5e02 csum-file: rename hashclose() to finalize_hashfile()
The hashclose() method behaves very differently depending on the flags
parameter. In particular, the file descriptor is not always closed.

Perform a simple rename of "hashclose()" to "finalize_hashfile()" in
preparation for functional changes.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-02 14:27:30 -07:00
brian m. carlson
98a3beab6a csum-file: rename sha1file to hashfile
Rename struct sha1file to struct hashfile, along with all of its related
functions.

The transformation in this commit was made by global search-and-replace.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-02-02 11:28:41 -08:00
brian m. carlson
81c58cd452 pack-write: switch various SHA-1 values to abstract forms
Convert various uses of hardcoded 20- and 40-based numbers to use
the_hash_algo, along with direct calls to SHA-1.  Adjust the names of
variables to refer to "hash" instead of "sha1".

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
Jeff King
90dca6710e avoid looking at errno for short read_in_full() returns
When a caller tries to read a particular set of bytes via
read_in_full(), there are three possible outcomes:

  1. An error, in which case -1 is returned and errno is
     set.

  2. A short read, in which fewer bytes are returned and
     errno is unspecified (we never saw a read error, so we
     may have some random value from whatever syscall failed
     last).

  3. The full read completed successfully.

Many callers handle cases 1 and 2 together by just checking
the result against the requested size. If their combined
error path looks at errno (e.g., by calling die_errno), they
may report a nonsense value.

Let's fix these sites by having them distinguish between the
two error cases. That avoids the random errno confusion, and
lets us give more detailed error messages.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-27 15:45:24 +09:00
brian m. carlson
e6a492b7be pack: convert struct pack_idx_entry to struct object_id
Convert struct pack_idx_entry to use struct object_id by changing the
definition and applying the following semantic patch, plus the standard
object_id transforms:

@@
struct pack_idx_entry E1;
@@
- E1.sha1
+ E1.oid.hash

@@
struct pack_idx_entry *E1;
@@
- E1->sha1
+ E1->oid.hash

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
Jeff King
594fa9998c odb_mkstemp: write filename into strbuf
The odb_mkstemp() function expects the caller to provide a
fixed buffer to write the resulting tempfile name into. But
it creates the template using snprintf without checking the
return value. This means we could silently truncate the
filename.

In practice, it's unlikely that the truncation would end in
the template-pattern that mkstemp needs to open the file. So
we'd probably end up failing either way, unless the path was
specially crafted.

The simplest fix would be to notice the truncation and die.
However, we can observe that most callers immediately
xstrdup() the result anyway. So instead, let's switch to
using a strbuf, which is easier for them (and isn't a big
deal for the other 2 callers, who can just strbuf_release
when they're done with it).

Note that many of the callers used static buffers, but this
was purely to avoid putting a large buffer on the stack. We
never passed the static buffers out of the function, so
there's no complicated memory handling we need to change.

Signed-off-by: Jeff King <peff@peff.net>
2017-03-28 15:28:04 -07:00
Jeff King
892e723afd do not check odb_mkstemp return value for errors
The odb_mkstemp function does not return an error; it dies
on failure instead. But many of its callers compare the
resulting descriptor against -1 and die themselves.

Mostly this is just pointless, but it does raise a question
when looking at the callers: if they show the results of the
"template" buffer after a failure, what's in it? The answer
is: it doesn't matter, because it cannot happen.

So let's make that clear by removing the bogus error checks.
In bitmap_writer_finish(), we can drop the error-handling
code entirely. In the other two cases, it's shared with the
open() in another code path; we can just move the
error-check next to that open() call.

And while we're at it, let's flesh out the function's
docstring a bit to make the error behavior clear.

Signed-off-by: Jeff King <peff@peff.net>
2017-03-28 15:28:04 -07:00
Jeff King
7202a6fa87 encode_in_pack_object_header: respect output buffer length
The encode_in_pack_object_header() writes a variable-length
header to an output buffer, but it doesn't actually know
long the buffer is. At first glance, this looks like it
might be possible to overflow.

In practice, this is probably impossible. The smallest
buffer we use is 10 bytes, which would hold the header for
an object up to 2^67 bytes. Obviously we're not likely to
see such an object, but we might worry that an object could
lie about its size (causing us to overflow before we realize
it does not actually have that many bytes). But the argument
is passed as a uintmax_t. Even on systems that have __int128
available, uintmax_t is typically restricted to 64-bit by
the ABI.

So it's unlikely that a system exists where this could be
exploited. Still, it's easy enough to use a normal out/len
pair and make sure we don't write too far. That protects the
hypothetical 128-bit system, makes it harder for callers to
accidentally specify a too-small buffer, and makes the
resulting code easier to audit.

Note that the one caller in fast-import tried to catch such
a case, but did so _after_ the call (at which point we'd
have already overflowed!). This check can now go away.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-24 12:34:07 -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
3157c880f6 sha1_file: drop free_pack_by_name
The point of this function is to drop an entry from the
"packed_git" cache that points to a file we might be
overwriting, because our contents may not be the same (and
hence the only caller was pack-objects as it moved a
temporary packfile into place).

In older versions of git, this could happen because the
names of packfiles were derived from the set of objects they
contained, not the actual bits on disk. But since 1190a1a
(pack-objects: name pack files after trailer hash,
2013-12-05), the name reflects the actual bits on disk, and
any two packfiles with the same name can be used
interchangeably.

Dropping this function not only saves a few lines of code,
it makes the lifetime of "struct packed_git" much easier to
reason about: namely, we now do not ever free these structs.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-07-29 11:05:06 -07:00
René Scharfe
d773144417 pack-write: simplify index_pack_lockfile using skip_prefix() and xstrfmt()
Get rid of magic string length constants by using skip_prefix() instead
of memcmp() and use xstrfmt() for building a string instead of a
PATH_MAX-sized buffer, snprintf() and xstrdup().

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-09-02 10:37:24 -07:00
Sun He
5889271114 finish_tmp_packfile():use strbuf for pathname construction
The old version fixes a maximum length on the buffer, which could be a problem
if one is not certain of the length of get_object_directory().
Using strbuf can avoid the protential bug.

Helped-by: Michael Haggerty <mhagger@alum.mit.edu>
Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Sun He <sunheehnus@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-03-03 12:15:10 -08:00
Junio C Hamano
0f9e62e084 Merge branch 'jk/pack-bitmap'
Borrow the bitmap index into packfiles from JGit to speed up
enumeration of objects involved in a commit range without having to
fully traverse the history.

* jk/pack-bitmap: (26 commits)
  ewah: unconditionally ntohll ewah data
  ewah: support platforms that require aligned reads
  read-cache: use get_be32 instead of hand-rolled ntoh_l
  block-sha1: factor out get_be and put_be wrappers
  do not discard revindex when re-preparing packfiles
  pack-bitmap: implement optional name_hash cache
  t/perf: add tests for pack bitmaps
  t: add basic bitmap functionality tests
  count-objects: recognize .bitmap in garbage-checking
  repack: consider bitmaps when performing repacks
  repack: handle optional files created by pack-objects
  repack: turn exts array into array-of-struct
  repack: stop using magic number for ARRAY_SIZE(exts)
  pack-objects: implement bitmap writing
  rev-list: add bitmap mode to speed up object lists
  pack-objects: use bitmaps when packing objects
  pack-objects: split add_object_entry
  pack-bitmap: add support for bitmap indexes
  documentation: add documentation for the bitmap format
  ewah: compressed bitmap implementation
  ...
2014-02-27 14:01:48 -08:00
Junio C Hamano
f06a5e607d Merge branch 'jk/sha1write-void'
Code clean-up.

* jk/sha1write-void:
  do not pretend sha1write returns errors
2014-01-10 10:33:09 -08:00
Vicent Marti
7cc8f97108 pack-objects: implement bitmap writing
This commit extends more the functionality of `pack-objects` by allowing
it to write out a `.bitmap` index next to any written packs, together
with the `.idx` index that currently gets written.

If bitmap writing is enabled for a given repository (either by calling
`pack-objects` with the `--write-bitmap-index` flag or by having
`pack.writebitmaps` set to `true` in the config) and pack-objects is
writing a packfile that would normally be indexed (i.e. not piping to
stdout), we will attempt to write the corresponding bitmap index for the
packfile.

Bitmap index writing happens after the packfile and its index has been
successfully written to disk (`finish_tmp_packfile`). The process is
performed in several steps:

    1. `bitmap_writer_set_checksum`: this call stores the partial
       checksum for the packfile being written; the checksum will be
       written in the resulting bitmap index to verify its integrity

    2. `bitmap_writer_build_type_index`: this call uses the array of
       `struct object_entry` that has just been sorted when writing out
       the actual packfile index to disk to generate 4 type-index bitmaps
       (one for each object type).

       These bitmaps have their nth bit set if the given object is of
       the bitmap's type. E.g. the nth bit of the Commits bitmap will be
       1 if the nth object in the packfile index is a commit.

       This is a very cheap operation because the bitmap writing code has
       access to the metadata stored in the `struct object_entry` array,
       and hence the real type for each object in the packfile.

    3. `bitmap_writer_reuse_bitmaps`: if there exists an existing bitmap
       index for one of the packfiles we're trying to repack, this call
       will efficiently rebuild the existing bitmaps so they can be
       reused on the new index. All the existing bitmaps will be stored
       in a `reuse` hash table, and the commit selection phase will
       prioritize these when selecting, as they can be written directly
       to the new index without having to perform a revision walk to
       fill the bitmap. This can greatly speed up the repack of a
       repository that already has bitmaps.

    4. `bitmap_writer_select_commits`: if bitmap writing is enabled for
       a given `pack-objects` run, the sequence of commits generated
       during the Counting Objects phase will be stored in an array.

       We then use that array to build up the list of selected commits.
       Writing a bitmap in the index for each object in the repository
       would be cost-prohibitive, so we use a simple heuristic to pick
       the commits that will be indexed with bitmaps.

       The current heuristics are a simplified version of JGit's
       original implementation. We select a higher density of commits
       depending on their age: the 100 most recent commits are always
       selected, after that we pick 1 commit of each 100, and the gap
       increases as the commits grow older. On top of that, we make sure
       that every single branch that has not been merged (all the tips
       that would be required from a clone) gets their own bitmap, and
       when selecting commits between a gap, we tend to prioritize the
       commit with the most parents.

       Do note that there is no right/wrong way to perform commit
       selection; different selection algorithms will result in
       different commits being selected, but there's no such thing as
       "missing a commit". The bitmap walker algorithm implemented in
       `prepare_bitmap_walk` is able to adapt to missing bitmaps by
       performing manual walks that complete the bitmap: the ideal
       selection algorithm, however, would select the commits that are
       more likely to be used as roots for a walk in the future (e.g.
       the tips of each branch, and so on) to ensure a bitmap for them
       is always available.

    5. `bitmap_writer_build`: this is the computationally expensive part
       of bitmap generation. Based on the list of commits that were
       selected in the previous step, we perform several incremental
       walks to generate the bitmap for each commit.

       The walks begin from the oldest commit, and are built up
       incrementally for each branch. E.g. consider this dag where A, B,
       C, D, E, F are the selected commits, and a, b, c, e are a chunk
       of simplified history that will not receive bitmaps.

            A---a---B--b--C--c--D
                     \
                      E--e--F

       We start by building the bitmap for A, using A as the root for a
       revision walk and marking all the objects that are reachable
       until the walk is over. Once this bitmap is stored, we reuse the
       bitmap walker to perform the walk for B, assuming that once we
       reach A again, the walk will be terminated because A has already
       been SEEN on the previous walk.

       This process is repeated for C, and D, but when we try to
       generate the bitmaps for E, we can reuse neither the current walk
       nor the bitmap we have generated so far.

       What we do now is resetting both the walk and clearing the
       bitmap, and performing the walk from scratch using E as the
       origin. This new walk, however, does not need to be completed.
       Once we hit B, we can lookup the bitmap we have already stored
       for that commit and OR it with the existing bitmap we've composed
       so far, allowing us to limit the walk early.

       After all the bitmaps have been generated, another iteration
       through the list of commits is performed to find the best XOR
       offsets for compression before writing them to disk. Because of
       the incremental nature of these bitmaps, XORing one of them with
       its predecesor results in a minimal "bitmap delta" most of the
       time. We can write this delta to the on-disk bitmap index, and
       then re-compose the original bitmaps by XORing them again when
       loaded.

       This is a phase very similar to pack-object's `find_delta` (using
       bitmaps instead of objects, of course), except the heuristics
       have been greatly simplified: we only check the 10 bitmaps before
       any given one to find best compressing one. This gives good
       results in practice, because there is locality in the ordering of
       the objects (and therefore bitmaps) in the packfile.

     6. `bitmap_writer_finish`: the last step in the process is
	serializing to disk all the bitmap data that has been generated
	in the two previous steps.

	The bitmap is written to a tmp file and then moved atomically to
	its final destination, using the same process as
	`pack-write.c:write_idx_file`.

Signed-off-by: Vicent Marti <tanoku@gmail.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-12-30 12:19:22 -08:00
Jeff King
9af270e8c2 do not pretend sha1write returns errors
The sha1write function returns an int, but it will always be
"0". The failure-prone parts of the function happen in the
"flush" callback, which cannot pass an error back to us. So
we just end up calling die() during the flush.

Let's just drop the return value altogether, as it only
confuses callers into thinking that it might be useful.

Only one call site actually checked the return value. We can
drop that check, since it just led to a die() anyway.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-12-26 11:50:20 -08:00
Jeff King
1190a1acf8 pack-objects: name pack files after trailer hash
Our current scheme for naming packfiles is to calculate the
sha1 hash of the sorted list of objects contained in the
packfile. This gives us a unique name, so we are reasonably
sure that two packs with the same name will contain the same
objects.

It does not, however, tell us that two such packs have the
exact same bytes. This makes things awkward if we repack the
same set of objects. Due to run-to-run variations, the bytes
may not be identical (e.g., changed zlib or git versions,
different source object reuse due to new packs in the
repository, or even different deltas due to races during a
multi-threaded delta search).

In theory, this could be helpful to a program that cares
that the packfile contains a certain set of objects, but
does not care about the particular representation. In
practice, no part of git makes use of that, and in many
cases it is potentially harmful. For example, if a dumb http
client fetches the .idx file, it must be sure to get the
exact .pack that matches it. Similarly, a partial transfer
of a .pack file cannot be safely resumed, as the actual
bytes may have changed.  This could also affect a local
client which opened the .idx and .pack files, closes the
.pack file (due to memory or file descriptor limits), and
then re-opens a changed packfile.

In all of these cases, git can detect the problem, as we
have the sha1 of the bytes themselves in the pack trailer
(which we verify on transfer), and the .idx file references
the trailer from the matching packfile. But it would be
simpler and more efficient to actually get the correct
bytes, rather than noticing the problem and having to
restart the operation.

This patch simply uses the pack trailer sha1 as the pack
name. It should be similarly unique, but covers the exact
representation of the objects. Other parts of git should not
care, as the pack name is returned by pack-objects and is
essentially opaque.

One test needs to be updated, because it actually corrupts a
pack and expects that re-packing the corrupted bytes will
use the same name. It won't anymore, but we can easily just
use the name that pack-objects hands back.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-12-05 15:40:11 -08:00
Ævar Arnfjörð Bjarmason
ab1900a36e Appease Sun Studio by renaming "tmpfile"
On Solaris the system headers define the "tmpfile" name, which'll
cause Git compiled with Sun Studio 12 Update 1 to whine about us
redefining the name:

    "pack-write.c", line 76: warning: name redefined by pragma redefine_extname declared static: tmpfile     (E_PRAGMA_REDEFINE_STATIC)
    "sha1_file.c", line 2455: warning: name redefined by pragma redefine_extname declared static: tmpfile    (E_PRAGMA_REDEFINE_STATIC)
    "fast-import.c", line 858: warning: name redefined by pragma redefine_extname declared static: tmpfile   (E_PRAGMA_REDEFINE_STATIC)
    "builtin/index-pack.c", line 175: warning: name redefined by pragma redefine_extname declared static: tmpfile    (E_PRAGMA_REDEFINE_STATIC)

Just renaming the "tmpfile" variable to "tmp_file" in the relevant
places is the easiest way to fix this.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-12-21 10:21:04 -08:00
Junio C Hamano
48b303675a Merge branch 'jc/stream-to-pack'
* jc/stream-to-pack:
  bulk-checkin: replace fast-import based implementation
  csum-file: introduce sha1file_checkpoint
  finish_tmp_packfile(): a helper function
  create_tmp_packfile(): a helper function
  write_pack_header(): a helper function

Conflicts:
	pack.h
2011-12-16 22:33:40 -08:00
Junio C Hamano
68be2fea50 receive-pack, fetch-pack: reject bogus pack that records objects twice
When receive-pack & fetch-pack are run and store the pack obtained over
the wire to a local repository, they internally run the index-pack command
with the --strict option. Make sure that we reject incoming packfile that
records objects twice to avoid spreading such a damage.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-11-16 22:05:21 -08:00
Junio C Hamano
0e990530ae finish_tmp_packfile(): a helper function
Factor out a small logic out of the private write_pack_file() function
in builtin/pack-objects.c.

This changes the order of finishing multi-pack generation slightly. The
code used to

 - adjust shared perm of temporary packfile
 - rename temporary packfile to the final name
 - update mtime of the packfile under the final name
 - adjust shared perm of temporary idxfile
 - rename temporary idxfile to the final name

but because the helper does not want to do the mtime thing, the updated
code does that step first and then all the rest.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-10-28 12:34:09 -07:00
Junio C Hamano
cdf9db3c83 create_tmp_packfile(): a helper function
Factor out a small logic out of the private write_pack_file() function
in builtin/pack-objects.c

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-10-28 11:52:14 -07:00
Junio C Hamano
c0ad465725 write_pack_header(): a helper function
Factor out a small logic out of the private write_pack_file() function
in builtin/pack-objects.c

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-10-28 11:40:48 -07:00
Junio C Hamano
3c9fc074c2 index-pack --verify: read anomalous offsets from v2 idx file
A pack v2 .idx file usually records offset using 64-bit representation
only when the offset does not fit within 31-bit, but you can handcraft
your .idx file to record smaller offset using 64-bit, storing all zero
in the upper 4-byte.  By inspecting the original idx file when running
index-pack --verify, encode such low offsets that do not need to be in
64-bit but are encoded using 64-bit just like the original idx file so
that we can still validate the pack/idx pair by comparing the idx file
recomputed with the original.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-02-27 23:29:03 -08:00
Junio C Hamano
fb956c1f44 write_idx_file: need_large_offset() helper function
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-02-27 23:29:03 -08:00
Junio C Hamano
e337a04de2 index-pack: --verify
Given an existing .pack file and the .idx file that describes it,
this new mode of operation reads and re-index the packfile and makes
sure the existing .idx file matches the result byte-for-byte.

All the objects in the .pack file are validated during this operation as
well.  Unlike verify-pack, which visits each object described in the .idx
file in the SHA-1 order, index-pack efficiently exploits the delta-chain
to avoid rebuilding the objects that are used as the base of deltified
objects over and over again while validating the objects, resulting in
much quicker verification of the .pack file and its .idx file.

This version however cannot verify a .pack/.idx pair with a handcrafted v2
index that uses 64-bit offset representation for offsets that would fit
within 31-bit. You can create such an .idx file by giving a custom offset
to --index-version option to the command.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-02-27 23:29:03 -08:00
Junio C Hamano
ebcfb3791a write_idx_file: introduce a struct to hold idx customization options
Remove two globals, pack_idx_default version and pack_idx_off32_limit,
and place them in a pack_idx_option structure.  Allow callers to pass
it to write_idx_file() as a parameter.

Adjust all callers to the API change.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-02-27 23:29:03 -08:00
Nicolas Pitre
f965c525a4 move encode_in_pack_object_header() to a better place
Commit 1b22b6c897 made duplicated versions of encode_header() into a
common version called encode_in_pack_object_header(). There is however
a better location that sha1_file.c for such a function though, as
sha1_file.c contains nothing related to the creation of packs, and
it is quite populated already.

Also the comment that was moved to the header file should really remain
near the function as it covers implementation details and provides no
information about the actual function interface.

Signed-off-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-02-23 13:10:56 -08:00
Linus Torvalds
3bb7256281 make "index-pack" a built-in
This required some fairly trivial packfile function 'const' cleanup,
since the builtin commands get a const char *argv[] array.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-01-22 10:10:27 -08:00
Thomas Rast
d824cbba02 Convert existing die(..., strerror(errno)) to die_errno()
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>
2009-06-27 11:14:53 -07:00
Junio C Hamano
bb0cebd7d0 Merge branch 'jc/maint-1.6.0-pack-directory'
* jc/maint-1.6.0-pack-directory:
  Make sure objects/pack exists before creating a new pack
2009-02-25 14:50:05 -08:00
Junio C Hamano
6e180cdcec Make sure objects/pack exists before creating a new pack
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>
2009-02-25 14:39:42 -08:00
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
Petr Baudis
8b4eb6b6cd Do not perform cross-directory renames when creating packs
A comment on top of create_tmpfile() describes caveats ('can have
problems on various systems (FAT, NFS, Coda)') that should apply
in this situation as well.  This in the end did not end up solving
any of my personal problems, but it might be a useful cleanup patch
nevertheless.

Signed-off-by: Petr Baudis <pasky@suse.cz>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-09-22 12:19:14 -07:00
Nicolas Pitre
d35825da6d fixup_pack_header_footer(): use nicely aligned buffer sizes
It should be more efficient to use nicely aligned buffer sizes, either
for filesystem operations or SHA1 checksums.  Also, using a relatively
small nominal size might allow for the data to remain in L1 cache
between both SHA1_Update() calls.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-08-29 21:51:28 -07:00