When some operations are interrupted (or "die()'d" or crashed) then the
partial object/pack/index file may remain around. Make it more obvious
in their name that those files are temporary stuff and can be cleaned up
if no operation is in progress.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
When appending objects to a pack, make sure the appended data is really
what we expect instead of simply loading potentially corrupted objects
and legitimating them by computing a SHA1 of that corrupt data.
With this the sha1_object() can lose its test_for_collision parameter
which is now redundent.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
Use hash_sha1_file() instead of duplicating code to compute object SHA1.
While at it make it accept a const pointer.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
Waaaaaaay back Git was considered to be secure as it never overwrote
an object it already had. This was ensured by always unpacking the
packfile received over the network (both in fetch and receive-pack)
and our already existing logic to not create a loose object for an
object we already have.
Lately however we keep "large-ish" packfiles on both fetch and push
by running them through index-pack instead of unpack-objects. This
would let an attacker perform a birthday attack.
How? Assume the attacker knows a SHA-1 that has two different
data streams. He knows the client is likely to have the "good"
one. So he sends the "evil" variant to the other end as part of
a "large-ish" packfile. The recipient keeps that packfile, and
indexes it. Now since this is a birthday attack there is a SHA-1
collision; two objects exist in the repository with the same SHA-1.
They have *very* different data streams. One of them is "evil".
Currently the poor recipient cannot tell the two objects apart,
short of by examining the timestamp of the packfiles. But lets
say the recipient repacks before he realizes he's been attacked.
We may wind up packing the "evil" version of the object, and deleting
the "good" one. This is made *even more likely* by Junio's recent
rearrange_packed_git patch (b867092f).
It is extremely unlikely for a SHA1 collisions to occur, but if it
ever happens with a remote (hence untrusted) object we simply must
not let the fetch succeed.
Normally received packs should not contain objects we already have.
But when they do we must ensure duplicated objects with the same SHA1
actually contain the same data.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
We shouldn't attempt to assign constant strings into char*, as the
string is not writable at runtime. Likewise we should always be
treating unsigned values as unsigned values, not as signed values.
Most of these are very straightforward. The only exception is the
(unnecessary) xstrdup/free in builtin-branch.c for the detached
head case. Since this is a user-level interactive type program
and that particular code path is executed no more than once, I feel
that the extra xstrdup call is well worth the easy elimination of
this warning.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
A filesystem might not be able to completely supply our pread
request in one system call, such as if we are reading data from a
network file system and the requested length is just simply huge.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
We currently have two parallel notation for dealing with object types
in the code: a string and a numerical value. One of them is obviously
redundent, and the most used one requires more stack space and a bunch
of strcmp() all over the place.
This is an initial step for the removal of the version using a char array
found in object reading code paths. The patch is unfortunately large but
there is no sane way to split it in smaller parts without breaking the
system.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
Sometime typename() is used, sometimes type_names[] is accessed directly.
Let's enforce typename() all the time which allows for validating the
type.
Also let's add a function to go from a name to a type and use it instead
of manual memcpy() when appropriate.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
This patch fixes issues mentioned by Junio, Nico and Simon:
- I forgot to convert the usage string when removing the "--" from
the subcommands,
- a style fix in the bundle_header,
- use xread() instead of read(),
- use write_or_die() instead of write(),
- make the bundle header extensible,
- fail if the whitespace after a sha1 of a reference is missing,
- close() the fds passed to a subprocess,
- in verify_bundle(), do not use "rev-list --stdin", but rather
pass the revs directly (avoiding a fork()),
- fix a corrupted comment in show_object(), and
- fix the size check in index_pack.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>
Some workflows require use of repositories on machines that cannot be
connected, preventing use of git-fetch / git-push to transport objects and
references between the repositories.
git-bundle provides an alternate transport mechanism, effectively allowing
git-fetch and git-pull to operate using sneakernet transport. `git-bundle
create` allows the user to create a bundle containing one or more branches
or tags, but with specified basis assumed to exist on the target
repository. At the receiving end, git-bundle acts like git-fetch-pack,
allowing the user to invoke git-fetch or git-pull using the bundle file as
the URL. git-fetch and git-ls-remote determine they have a bundle URL by
checking that the URL points to a file, but are otherwise unchanged in
operation with bundles.
The original patch was done by Mark Levedahl <mdl123@verizon.net>.
It was updated to make git-bundle a builtin, and get rid of the tar
format: now, the first line is supposed to say "# v2 git bundle", the next
lines either contain a prerequisite ("-" followed by the hash of the
needed commit), or a ref (the hash of a commit, followed by the name of
the ref), and finally the pack. As a result, the bundle argument can be
"-" now.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>
This mechanically converts strncmp() to use prefixcmp(), but only when
the parameters match specific patterns, so that they can be verified
easily. Leftover from this will be fixed in a separate step, including
idiotic conversions like
if (!strncmp("foo", arg, 3))
=>
if (!(-prefixcmp(arg, "foo")))
This was done by using this script in px.perl
#!/usr/bin/perl -i.bak -p
if (/strncmp\(([^,]+), "([^\\"]*)", (\d+)\)/ && (length($2) == $3)) {
s|strncmp\(([^,]+), "([^\\"]*)", (\d+)\)|prefixcmp($1, "$2")|;
}
if (/strncmp\("([^\\"]*)", ([^,]+), (\d+)\)/ && (length($1) == $3)) {
s|strncmp\("([^\\"]*)", ([^,]+), (\d+)\)|(-prefixcmp($2, "$1"))|;
}
and running:
$ git grep -l strncmp -- '*.c' | xargs perl px.perl
Signed-off-by: Junio C Hamano <junkio@cox.net>
We have a number of badly checked write() calls. Often we are
expecting write() to write exactly the size we requested or fail,
this fails to handle interrupts or short writes. Switch to using
the new write_in_full(). Otherwise we at a minimum need to check
for EINTR and EAGAIN, where this is appropriate use xwrite().
Note, the changes to config handling are much larger and handled
in the next patch in the sequence.
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
We have a number of badly checked read() calls. Often we are
expecting read() to read exactly the size we requested or fail, this
fails to handle interrupts or short reads. Add a read_in_full()
providing those semantics. Otherwise we at a minimum need to check
for EINTR and EAGAIN, where this is appropriate use xread().
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
If ever new object types are added for future extensions then better
have current git version report them as "unknown" instead of
"corrupted".
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
This is a mechanical clean-up of the way *.c files include
system header files.
(1) sources under compat/, platform sha-1 implementations, and
xdelta code are exempt from the following rules;
(2) the first #include must be "git-compat-util.h" or one of
our own header file that includes it first (e.g. config.h,
builtin.h, pkt-line.h);
(3) system headers that are included in "git-compat-util.h"
need not be included in individual C source files.
(4) "git-compat-util.h" does not have to include subsystem
specific header files (e.g. expat.h).
Signed-off-by: Junio C Hamano <junkio@cox.net>
It was reported by Randal L. Schwartz <merlyn@stonehenge.com> that
indexing the Linux repository ~150MB pack takes about an hour on OS x
while it's a minute on Linux. It seems that the OS X mmap()
implementation is more than 2 orders of magnitude slower than the Linux
one.
Linus proposed a patch replacing mmap() with pread() bringing index-pack
performance on OS X in line with the Linux one. The performances on
Linux also improved by a small margin.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
git-index-pack can call memcpy with overlapping source and destination
buffers. The patch below makes it use memmove instead.
If you want to demonstrate a failure, add the following two lines
+ if (input_offset < input_len)
+ abort ();
before the existing memcpy call (shown in the patch below),
and then run this:
(cd t; sh ./t5500-fetch-pack.sh)
Signed-off-by: Jim Meyering <jim@meyering.net>
Signed-off-by: Junio C Hamano <junkio@cox.net>
The declaration of discard_cache() in cache.h already has its "void".
Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <junkio@cox.net>
This makes both git-fetch and git-push (fetch-pack and receive-pack)
safe against a possible race with aparallel git-repack -a -d that could
prune the new pack while it is not yet referenced, and remove the .keep
file after refs have been updated.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
If by chance we receive a pack which content (list of objects) matches
another pack that we already have, and if that pack is marked with a
.keep file, then we should not overwrite it.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
Some applications which invoke unpack-objects or index-pack --stdin
may want to examine the pack header to determine the number of
objects contained in the pack and use that value to determine which
executable to invoke to handle the rest of the pack stream.
However if the caller consumes the pack header from the input stream
then its no longer available for unpack-objects or index-pack --stdin,
both of which need the version and object count to process the stream.
This change introduces --pack_header=ver,cnt as a command line option
that the caller can supply to indicate it has already consumed the
pack header and what version and object count were found in that
header. As this option is only meant for low level applications
such as receive-pack we are not documenting it at this time.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
To prevent a race condition between `index-pack --stdin` and
`repack -a -d` where the repack deletes the newly created pack
file before any refs are updated to reference objects contained
within it we mark the pack file as one that should be kept. This
removes it from the list of packs that `repack -a -d` will consider
for removal.
Callers such as `receive-pack` which want to invoke `index-pack`
should use this new --keep option to prevent the newly created pack
and index file pair from being deleted before they have finished any
related ref updates. Only after all ref updates have been finished
should the associated .keep file be removed.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
Use proper english. Be more exact in one comment.
[jc: I threw in a bit of style clean-up as well]
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
It appears that git-unpack-objects writes the last part of the input
buffer to stdout after the pack has been parsed. This looks a bit
suspicious since the last fill() might have filled the buffer up to
the 4096 byte limit and more data might still be pending on stdin,
but since this is about being a drop-in replacement for unpack-objects
let's simply duplicate the same behavior for now.
[jc: with fix-up appeared in Nico's sleep]
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
This is more interesting to look at when performing a big fetch.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
A new flag, --fix-thin, instructs git-index-pack to append any missing
objects to a thin pack to make it self contained and indexable. Of course
objects missing from the pack must be present elsewhere in the local
repository.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
A new flag, --stdin, allows for a pack to be received over a stream.
When this flag is provided, the pack content is written to either
the named pack file or directly to the object repository under the
same name as produced by git-repack. The pack index is written as
well with the corresponding base name, unless the index name is
overriden with -o.
With this patch, git-index-pack could be used instead of
git-unpack-objects when fetching remote objects but only with
non "thin" packs for now.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
This patch only adds the streaming capability to index-pack. Although
the code is different it has the exact same functionality as before to
make sure nothing broke.
This is in preparation for receiving packs over the net, parse them on
the fly, fix them up if they are "thin" packs, and keep the resulting
pack instead of exploding it into loose objects. But such functionality
should come separately.
One immediate advantage of this patch is that index-pack can now deal
with packs up to 4GB in size even on 32-bit architectures since the pack
is not entirely mmap()'d all at once anymore.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
The "union delta_base" is a strange beast. It is a 20-byte
binary blob key to search a binary searchable deltas[] array,
each element of which uses it to represent its base object with
either a full 20-byte SHA-1 or an offset in the pack. Which
representation is used is determined by another field of the
deltas[] array element, obj->type, so there is no room for
confusion, as long as we make sure we compare the keys for the
same type only with appropriate length. The code compared the
full union with memcmp().
When storing the in-pack offset, the union was first cleared
before storing an unsigned long, so comparison worked fine.
On 64-bit architectures, however, the union typically is 24-byte
long; the code did not clear the remaining 4-byte alignment
padding when storing a full 20-byte SHA-1 representation. Using
memcmp() to compare the whole union was wrong.
This fixes the comparison to look at the first 20-bytes of the
union, regardless of the architecture. As long as ulong is
smaller than 20-bytes this works fine.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
This adds a new object, namely OBJ_OFS_DELTA, renames OBJ_DELTA to
OBJ_REF_DELTA to better make the distinction between those two delta
objects, and adds support for the handling of those new delta objects
in sha1_file.c only.
The OBJ_OFS_DELTA contains a relative offset from the delta object's
position in a pack instead of the 20-byte SHA1 reference to identify
the base object. Since the base is likely to be not so far away, the
relative offset is more likely to have a smaller encoding on average
than an absolute offset. And for those delta objects the base must
always be stored first because there is no way to know the distance of
later objects when streaming a pack. Hence this relative offset is
always meant to be negative.
The offset encoding is slightly denser than the one used for object
size -- credits to <linux@horizon.com> (whoever this is) for bringing
it to my attention.
This allows for pack size reduction between 3.2% (Linux-2.6) to over 5%
(linux-historic). Runtime pack access should be faster too since delta
replay does skip a search in the pack index for each delta in a chain.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
This abstracts away the size of the hash values when copying them
from memory location to memory location, much as the introduction
of hashcmp abstracted away hash value comparsion.
A few call sites were using char* rather than unsigned char* so
I added the cast rather than open hashcpy to be void*. This is a
reasonable tradeoff as most call sites already use unsigned char*
and the existing hashcmp is also declared to be unsigned char*.
[jc: Splitted the patch to "master" part, to be followed by a
patch for merge-recursive.c which is not in "master" yet.
Fixed the cast in the latter hunk to combine-diff.c which was
wrong in the original.
Also converted ones left-over in combine-diff.c, diff-lib.c and
upload-pack.c ]
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
Introduces global inline:
hashcmp(const unsigned char *sha1, const unsigned char *sha2)
Uses memcmp for comparison and returns the result based on the length of
the hash name (a future runtime decision).
Acked-by: Alex Riesen <raa.lkml@gmail.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>
As Fredrik points out the current interface of has_extension() is
potentially confusing. Its parameters include both a nul-terminated
string and a length-limited string.
This patch drops the length argument, requiring two nul-terminated
strings; all callsites are updated. I checked that all of them indeed
provide nul-terminated strings. Filenames need to be nul-terminated
anyway if they are to be passed to open() etc. The performance penalty
of the additional strlen() is negligible compared to the system calls
which inevitably surround has_extension() calls.
Additionally, change has_extension() to use size_t inside instead of
int, as that is the exact type strlen() returns and memcmp() expects.
Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <junkio@cox.net>
The little helper has_extension() documents through its name what we are
trying to do and makes sure we don't forget the underrun check.
Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Junio C Hamano <junkio@cox.net>
This replaces occurences of "blob", "commit", "tag", and "tree",
where they're really used as type specifiers, which we already
have defined global constants for.
Signed-off-by: Peter Eriksen <s022018@student.dtu.dk>
Signed-off-by: Junio C Hamano <junkio@cox.net>
After experimenting with code to add the ability to encode a delta
against part of the deltified file, it turns out that resulting packs
are _bigger_ than when this ability is not used. The raw delta output
might be smaller, but it doesn't compress as well using gzip with a
negative net saving on average.
Said bit would in fact be more useful to allow for encoding the copying
of chunks larger than 64KB providing more savings with large files.
This will correspond to packs version 3.
While the current code still produces packs version 2, it is made future
proof so pack versions 2 and 3 are accepted. Any pack version 2 are
compatible with version 3 since the redefined bit was never used before.
When enough time has passed, code to use that bit to produce version 3
packs could be added.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
Avoid asking for zero bytes when that change simplifies overall
logic. Later we would change the wrapper to ask for 1 byte on
platforms that return NULL for zero byte request.
Signed-off-by: Junio C Hamano <junkio@cox.net>
Insufficient memory is allocated in index-pack.c to hold the *.idx name.
One more byte should be allocated to hold the terminating 0.
Signed-off-by: Pavel Roskin <proski@gnu.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
This changes the generation of hash packfiles have in their names, from
"hash of object names as fed to us" to "hash of object names in the
resulting pack, in the order they appear in the index file". The new
"git-index-pack" command is taught to output the computed hash value
to its standard output.
With this, we can store downloaded pack in a temporary file without
knowing its final name, run git-index-pack to generate idx for it
while finding out its final name, and then rename the pack and idx to
their final names.
Signed-off-by: Junio C Hamano <junkio@cox.net>
git-index-pack builds a pack index file for an existing packed
archive. With this utility a packed archive which was transferred
without the corresponding pack index can be added to objects/pack/
without repacking.
Signed-off-by: Sergey Vlasov <vsu@altlinux.ru>
Signed-off-by: Junio C Hamano <junkio@cox.net>
Nicolas Pitre