In a workload other than "git log" (without pathspec nor any option that
causes us to inspect trees and blobs), the recency pack order is said to
cause the access jump around quite a bit. Add a hook to allow us observe
how bad it is.
"git config core.logpackaccess /var/tmp/pal.txt" will give you the log
in the specified file.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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>
Wrap deflateInit, deflate, and deflateEnd for everybody, and the sole use
of deflateInit2 in remote-curl.c to tell the library to use gzip header
and trailer in git_deflate_init_gzip().
There is only one caller that cares about the status from deflateEnd().
Introduce git_deflate_end_gently() to let that sole caller retrieve the
status and act on it (i.e. die) for now, but we would probably want to
make inflate_end/deflate_end die when they ran out of memory and get
rid of the _gently() kind.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Every time I look at the read-loose-object codepath, legacy_loose_object()
function makes my brain go through mental contortion. When we were playing
with the experimental loose object format, it may have made sense to call
the traditional format "legacy", in the hope that the experimental one
will some day replace it to become official, but it never happened.
This renames the function (and negates its return value) to detect if we
are looking at the experimental format, and move the code around in its
caller which used to do "if we are looing at legacy, do this special case,
otherwise the normal case is this". The codepath to read from the loose
objects in experimental format is the "unlikely" case.
Someday after Git 2.0, we should drop the support of this format.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This finally gets rid of the inefficient verify-pack implementation that
walks objects in the packfile in their object name order and replaces it
with a call to index-pack --verify. As a side effect, it also removes
packed_object_info_detail() API which is rather expensive.
As this changes the way errors are reported (verify-pack used to rely on
the usual runtime error detection routine unpack_entry() to diagnose the
CRC errors in an entry in the *.idx file; index-pack --verify checks the
whole *.idx file in one go), update a test that expected the string "CRC"
to appear in the error message.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Using an unsigned type, we would fail to detect a read error and then
proceed to try to write (size_t)-1 bytes.
Signed-off-by: Jim Meyering <meyering@redhat.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* jc/bigfile:
Bigfile: teach "git add" to send a large file straight to a pack
index_fd(): split into two helper functions
index_fd(): turn write_object and format_check arguments into one flag
Make map_sha1_file(), parse_sha1_header() and unpack_sha1_header()
available to the streaming read API by exporting them via cache.h header
file.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
An object found in the delta-base cache is not guaranteed to
stay there, but we know it came from a pack and it is likely
to give us a quick access if we read_sha1_file() it right now,
which is a piece of useful information.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* jc/replacing:
read_sha1_file(): allow selective bypassing of replacement mechanism
inline lookup_replace_object() calls
read_sha1_file(): get rid of read_sha1_file_repl() madness
t6050: make sure we test not just commit replacement
Declare lookup_replace_object() in cache.h, not in commit.h
Conflicts:
environment.c
The original interface for sha1_object_info() takes an object name and
gives back a type and its size (the latter is given only when it was
asked). The new interface wraps its implementation and exposes a bit
more pieces of information that the interface used to discard, namely:
- where the object is stored (loose? cached? packed?)
- if packed, where in which packfile?
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
* In the earlier round, this used u.pack.delta to record the length of
the delta chain, but the caller is not necessarily interested in the
length of the delta chain per-se, but may only want to know if it is a
delta against another object or is stored as a deflated data. Calling
packed_object_info_detail() involves walking the reverse index chain to
compute the store size of the object and is unnecessarily expensive.
We could resurrect the code if a new caller wants to know, but I doubt
it.
Instead return an integer that can be given to typename() if
the caller wants a string, just like everybody else does.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* jc/convert:
convert: make it harder to screw up adding a conversion attribute
convert: make it safer to add conversion attributes
convert: give saner names to crlf/eol variables, types and functions
convert: rename the "eol" global variable to "core_eol"
* jc/bigfile:
Bigfile: teach "git add" to send a large file straight to a pack
index_fd(): split into two helper functions
index_fd(): turn write_object and format_check arguments into one flag
* jc/replacing:
read_sha1_file(): allow selective bypassing of replacement mechanism
inline lookup_replace_object() calls
read_sha1_file(): get rid of read_sha1_file_repl() madness
t6050: make sure we test not just commit replacement
Declare lookup_replace_object() in cache.h, not in commit.h
Since commit c793430 (Limit file descriptors used by packs, 2011-02-28),
the extra parameter added in f2e872aa (Work around EMFILE when there are
too many pack files, 2010-11-01) is not used anymore.
Remove it.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Acked-by: Shawn O. Pearce <spearce@spearce.org>
The way "object replacement" mechanism was tucked to the read_sha1_file()
interface was suboptimal in a couple of ways:
- Callers that want it to die with useful diagnosis upon seeing a corrupt
object does not have a way to say that they do not want any object
replacement.
- Callers who do not want it to die but want to handle the errors
themselves are told to arrange to call read_object(), but the function
does not use the replacement mechanism, and also it is a file scope
static function that not many callers can call to begin with.
This adds a read_sha1_file_extended() that takes a set of flags; the
callers of read_sha1_file() passes a flag READ_SHA1_FILE_REPLACE to ask
for object replacement mechanism to kick in.
Later, we could add another flag bit to tell the function to return an
error instead of dying and then remove the misguided "call read_object()
yourself".
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Most callers want to silently get a replacement object, and they do not
care what the real name of the replacement object is. Worse yet, no sane
interface to return the underlying object without replacement is provided.
Remove the function and make only the few callers that want the name of
the replacement object find it themselves.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When adding a new content to the repository, we have always slurped
the blob in its entirety in-core first, and computed the object name
and compressed it into a loose object file. Handling large binary
files (e.g. video and audio asset for games) has been problematic
because of this design.
At the middle level of "git add" callchain is an internal API
index_fd() that takes an open file descriptor to read from the
working tree file being added with its size. Teach it to call out to
fast-import when adding a large blob.
The write-out codepath in entry.c::write_entry() should be taught to
stream, instead of reading everything in core. This should not be so
hard to implement, especially if we limit ourselves only to loose
object files and non-delta representation in packfiles.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Split out the case where we do not know the size of the input (hence we
read everything into a strbuf before doing anything) to index_pipe(), and
the other case where we mmap or read the whole data to index_bulk().
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The "format_check" parameter tucked after the existing parameters is too
ugly an afterthought to live in any reasonable API.
Combine it with the other boolean parameter "write_object" into a single
"flags" parameter.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
I found that some doubled words had snuck back into projects from which
I'd already removed them, so now there's a "syntax-check" makefile rule in
gnulib to help prevent recurrence.
Running the command below spotted a few in git, too:
git ls-files | xargs perl -0777 -n \
-e 'while (/\b(then?|[iao]n|i[fst]|but|f?or|at|and|[dt])\s+\1\b/gims)' \
-e '{$n=($` =~ tr/\n/\n/ + 1); ($v=$&)=~s/\n/\\n/g;' \
-e 'print "$ARGV:$n:$v\n"}'
Signed-off-by: Jim Meyering <meyering@redhat.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The git-new-workdir script in contrib/ makes a new work tree by sharing
many subdirectories of the .git directory with the original repository.
When rerere.enabled is set in the original repository, but the user has
not encountered any conflicts yet, the original repository may not yet
have .git/rr-cache directory.
When rerere wants to run in a new work tree created from such a young
original repository, it fails to mkdir(2) .git/rr-cache that is a symlink
to a yet-to-be-created directory.
There are three possible approaches to this:
- A naive solution is not to create a symlink in the git-new-workdir
script to a directory the original does not have (yet). This is not a
solution, as we tend to lazily create subdirectories of .git/, and
having rerere.enabled configuration set is a strong indication that the
user _wants_ to have this lazy creation to happen;
- We could always create .git/rr-cache upon repository creation. This is
tempting but will not help people with existing repositories.
- Detect this case by seeing that mkdir(2) failed with EEXIST, checking
that the path is a symlink, and try running mkdir(2) on the link
target.
This patch solves the issue by doing the third one.
Strictly speaking, this is incomplete. It does not attempt to handle
relative symbolic link that points into the original repository, but this
is good enough to help people who use contrib/workdir/git-new-workdir
script.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In the spirit of v1.5.0.2~21 (Check for PRIuMAX rather than
NO_C99_FORMAT in fast-import.c, 2007-02-20), use PRIuMAX from
git-compat-util.h on all platforms instead of C99-specific formats
like %zu with dangerous fallbacks to %u or %lu.
So now C99-challenged platforms can build git without provoking
warnings or errors from printf, even if pointers do not have the same
size as an int or long.
The need for a fallback PRIuMAX is detected in git-compat-util.h with
"#ifndef PRIuMAX". So while at it, simplify the Makefile and configure
script by eliminating the NO_C99_FORMAT knob altogether.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* sp/maint-fd-limit:
sha1_file.c: Don't retain open fds on small packs
mingw: add minimum getrlimit() compatibility stub
Limit file descriptors used by packs
If a pack file is small enough that its entire contents fits within
one mmap window, mmap the file and then immediately close its file
descriptor. This reduces the number of file descriptors that are
needed to read from repositories with many tiny pack files, such
as one that has received 1000 pushes (and created 1000 small pack
files) since its last repack.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Rather than using 'errno == EMFILE' after a failed open() call
to indicate the process is out of file descriptors and an LRU
pack window should be closed, place a hard upper limit on the
number of open packs based on the actual rlimit of the process.
By using a hard upper limit that is below the rlimit of the current
process it is not necessary to check for EMFILE on every single
fd-allocating system call. Instead reserving 25 file descriptors
makes it safe to assume the system call won't fail due to being over
the filedescriptor limit. Here 25 is chosen as a WAG, but considers
3 for stdin/stdout/stderr, and at least a few for other Git code
to operate on temporary files. An additional 20 is reserved as it
is not known what the C library needs to perform other services on
Git's behalf, such as nsswitch or name resolution.
This fixes a case where running `git gc --auto` in a repository
with more than 1024 packs (but an rlimit of 1024 open fds) fails
due to the temporary output file not being able to allocate a
file descriptor. The output file is opened by pack-objects after
object enumeration and delta compression are done, both of which
have already opened all of the packs and fully populated the file
descriptor table.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Functions such as hashcmp that expect a binary SHA-1 value take
parameters of type "unsigned char *" to avoid accepting a textual
SHA-1 passed by mistake. Unfortunately, this means passing the string
literal EMPTY_TREE_SHA1_BIN requires an ugly cast. Tweak the
definition of EMPTY_TREE_SHA1_BIN to produce a value of more
convenient type.
In the future the definition might change to
extern const unsigned char empty_tree_sha1_bin[20];
#define EMPTY_TREE_SHA1_BIN empty_tree_sha1_bin
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Cached object store was added in d66b37b (Add pretend_sha1_file()
interface. - 2007-02-04) as a way to temporarily inject some objects
to object store.
But only read_sha1_file() knows about this store. While it will return
an object from this store, sha1_object_info() will happily say
"object not found".
Teach sha1_object_info() about the cached store for consistency.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Commits, trees and tags have structure. Don't let users feed git
with malformed ones. Sooner or later git will die() when
encountering them.
Note that this patch does not check semantics. A tree that points
to non-existent objects is perfectly OK (and should be so, users
may choose to add commit first, then its associated tree for example).
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The errno check added in commit 3ba7a06 "A loose object is not corrupt
if it cannot be read due to EMFILE" only checked for whether errno is
not ENOENT and thus incorrectly treated "no error" as an error
condition.
Because of that, it never reached the code path that would report that
the object is corrupted and instead caused funny errors like:
fatal: failed to read object 333c4768ce595793fdab1ef3a036413e2a883853: Success
So we have to extend the check to cover the case in which the object
file was successfully read, but its contents are corrupted.
Reported-by: Will Palmer <wmpalmer@gmail.com>
Signed-off-by: Björn Steinbrink <B.Steinbrink@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* jn/thinner-wrapper:
Remove pack file handling dependency from wrapper.o
pack-objects: mark file-local variable static
wrapper: give zlib wrappers their own translation unit
strbuf: move strbuf_branchname to sha1_name.c
path helpers: move git_mkstemp* to wrapper.c
wrapper: move odb_* to environment.c
wrapper: move xmmap() to sha1_file.c
As v1.7.0-rc0~43 (slim down "git show-index", 2010-01-21) explains,
use of xmalloc() brings in a dependency on zlib, the sha1 lib, and the
rest of git's object file access machinery via try_to_free_pack_memory.
That is overkill when xmalloc is just being used as a convenience
wrapper to exit when no memory is available.
So defer setting try_to_free_pack_memory as try_to_free_routine until
the first packfile is opened in add_packed_git().
After this change, a simple program using xmalloc() and no other
functions will not pull in any code from libgit.a aside from wrapper.o
and usage.o.
Improved-by: René Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
wrapper.o depends on sha1_file.o for a number of reasons. One is
release_pack_memory().
xmmap function calls mmap, discarding unused pack windows when
necessary to relieve memory pressure. Simple git programs using
wrapper.o as a friendly libc do not need this functionality.
So move xmmap to sha1_file.o, where release_pack_memory() is.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When opening any files in the object database, release unused pack
windows if the open(2) syscall fails due to EMFILE (too many open
files in this process). This allows Git to degrade gracefully on
a repository with thousands of pack files, and a commit stored in
a loose object in the middle of the history.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This utility function avoids an unnecessary update of the access time
for a loose object file. Just as the atime isn't useful on a loose
object, its not useful on the pack or the corresonding idx file.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git fsck" bails out with a claim that a loose object that cannot be
read but exists on the filesystem to be corrupt, which is wrong when
read_object() failed due to e.g. EMFILE.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Clarify the error reporting logic by moving the normal codepath (i.e. we
read the object we wanted to read correctly) up and return early.
The logic to report the name of the packfile with a corrupt object,
introduced by e8b15e6 (sha1_file: Show the the type and path to corrupt
objects, 2010-06-10), was totally bogus. The function that knows which
bad object came from what packfile is has_packed_and_bad(); make it report
which packfile the problem was found.
"Corrupt" is already an adjective, e.g. an object is "corrupt"; we do not
have to say "corrupted object".
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change the error message that's displayed when we encounter corrupt
objects to be more specific. We now print the type (loose or packed)
of corrupted objects, along with the full path to the file in
question.
Before:
$ git cat-file blob 909ef997367880aaf2133bafa1f1a71aa28e09df
fatal: object 909ef997367880aaf2133bafa1f1a71aa28e09df is corrupted
After:
$ git cat-file blob 909ef997367880aaf2133bafa1f1a71aa28e09df
fatal: loose object 909ef997367880aaf2133bafa1f1a71aa28e09df (stored in .git/objects/90/9ef997367880aaf2133bafa1f1a71aa28e09df) is corrupted
Knowing the path helps to quickly analyze what's wrong:
$ file .git/objects/90/9ef997367880aaf2133bafa1f1a71aa28e09df
.git/objects/90/9ef997367880aaf2133bafa1f1a71aa28e09df: empty
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This function takes a sha1 and produces a loose object
filename. It caches the location of the object directory so
that it can fill the sha1 information directly without
allocating a new buffer (and in its original incarnation,
without calling getenv(), though these days we cache that
with the code in environment.c).
This cached base directory can become stale, however, if in
a single process git changes the location of the object
directory (e.g., by running setup_work_tree, which will
chdir to the new worktree).
In most cases this isn't a problem, because we tend to set
up the git repository location and do any chdir()s before
actually looking up any objects, so the first lookup will
cache the correct location. In the case of reset --hard,
however, we do something like:
1. look up the commit object
2. notice we are doing --hard, run setup_work_tree
3. look up the tree object to reset
Step (3) fails because our cache object directory value is
bogus.
This patch simply removes the caching. We use a static
buffer instead of allocating one each time (the original
version treated the malloc'd buffer as a static, so there is
no change in calling semantics).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* sp/maint-dumb-http-pack-reidx:
http.c::new_http_pack_request: do away with the temp variable filename
http-fetch: Use temporary files for pack-*.idx until verified
http-fetch: Use index-pack rather than verify-pack to check packs
Allow parse_pack_index on temporary files
Extract verify_pack_index for reuse from verify_pack
Introduce close_pack_index to permit replacement
http.c: Remove unnecessary strdup of sha1_to_hex result
http.c: Don't store destination name in request structures
http.c: Drop useless != NULL test in finish_http_pack_request
http.c: Tiny refactoring of finish_http_pack_request
t5550-http-fetch: Use subshell for repository operations
http.c: Remove bad free of static block
* maint:
Documentation/gitdiffcore: fix order in pickaxe description
Documentation: fix minor inconsistency
Documentation: rebase -i ignores options passed to "git am"
hash_object: correction for zero length file
The check whether size is zero was done after if size <= SMALL_FILE_SIZE,
as result, zero size case was never triggered. Instead zero length file
was treated as any other small file. This did not caused any problem, but
if we have a special case for size equal to zero, it is better to make it
work and avoid redundant malloc().
Signed-off-by: Dmitry Potapov <dpotapov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The easiest way to verify a pack index is to open it through the
standard parse_pack_index function, permitting the header check
to happen when the file is mapped. However, the dumb HTTP client
needs to verify a pack index before its moved into its proper file
name within the objects/pack directory, to prevent a corrupt index
from being made available. So permit the caller to specify the
exact path of the index file.
For now we're still using the final destination name within the
sole call site in http.c, but eventually we will start to parse
the temporary path instead.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
By closing the pack index, a caller can later overwrite the index
with an updated index file, possibly after converting from v1 to
the v2 format. Because p->index_data is NULL after close, on the
next access the index will be opened again and the other members
will be updated with new data.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Until now, this has been part of the commit-tree builtin.
However, it is already used by other builtins (like commit,
merge, and notes), and it would be useful to access it from
library code.
The check_valid helper has to come along, too, but is given
a more library-ish name of "assert_sha1_type".
Otherwise, the code is unchanged. There are still a few
rough edges for a library function, like printing the utf8
warning to stderr, but we can address those if and when they
come up as inappropriate.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
These should take const buffers as input data, but zlib's
next_in pointer is not const-correct. Let's fix it at the
zlib level, though, so the cast happens in one obvious
place. This should be safe, as a similar cast is used in
zlib's example code for a const array.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* mm/mkstemps-mode-for-packfiles:
Use git_mkstemp_mode instead of plain mkstemp to create object files
git_mkstemps_mode: don't set errno to EINVAL on exit.
Use git_mkstemp_mode and xmkstemp_mode in odb_mkstemp, not chmod later.
git_mkstemp_mode, xmkstemp_mode: variants of gitmkstemps with mode argument.
Move gitmkstemps to path.c
Add a testcase for ACL with restrictive umask.
* nd/root-git:
Add test for using Git at root of file system
Support working directory located at root
Move offset_1st_component() to path.c
init-db, rev-parse --git-dir: do not append redundant slash
make_absolute_path(): Do not append redundant slash
Conflicts:
setup.c
sha1_file.c
* mm/mkstemps-mode-for-packfiles:
Use git_mkstemp_mode instead of plain mkstemp to create object files
git_mkstemps_mode: don't set errno to EINVAL on exit.
Use git_mkstemp_mode and xmkstemp_mode in odb_mkstemp, not chmod later.
git_mkstemp_mode, xmkstemp_mode: variants of gitmkstemps with mode argument.
Move gitmkstemps to path.c
Add a testcase for ACL with restrictive umask.
* np/compress-loose-object-memsave:
sha1_file: be paranoid when creating loose objects
sha1_file: don't malloc the whole compressed result when writing out objects
We used to unnecessarily give the read permission to group and others,
regardless of the umask, which isn't serious because the objects are
still protected by their containing directory, but isn't necessary
either.
Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We don't want the data being deflated and stored into loose objects
to be different from what we expect. While the deflated data is
protected by a CRC which is good enough for safe data retrieval
operations, we still want to be doubly sure that the source data used
at object creation time is still what we expected once that data has
been deflated and its CRC32 computed.
The most plausible data corruption may occur if the source file is
modified while Git is deflating and writing it out in a loose object.
Or Git itself could have a bug causing memory corruption. Or even bad
RAM could cause trouble. So it is best to make sure everything is
coherent and checksum protected from beginning to end.
To do so we compute the SHA1 of the data being deflated _after_ the
deflate operation has consumed that data, and make sure it matches
with the expected SHA1. This way we can rely on the CRC32 checked by
the inflate operation to provide a good indication that the data is still
coherent with its SHA1 hash. One pathological case we ignore is when
the data is modified before (or during) deflate call, but changed back
before it is hashed.
There is some overhead of course. Using 'git add' on a set of large files:
Before:
real 0m25.210s
user 0m23.783s
sys 0m1.408s
After:
real 0m26.537s
user 0m25.175s
sys 0m1.358s
The overhead is around 5% for full data coherency guarantee.
Signed-off-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Using read() instead of mmap() can be 39% speed up for 1Kb files and is
1% speed up 1Mb files. For larger files, it is better to use mmap(),
because the difference between is not significant, and when there is not
enough memory, mmap() performs much better, because it avoids swapping.
Signed-off-by: Dmitry Potapov <dpotapov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There is no real advantage to malloc the whole output buffer and
deflate the data in a single pass when writing loose objects. That is
like only 1% faster while using more memory, especially with large
files where memory usage is far more. It is best to deflate and write
the data out in small chunks reusing the same memory instead.
For example, using 'git add' on a few large files averaging 40 MB ...
Before:
21.45user 1.10system 0:22.57elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+828040outputs (0major+142640minor)pagefaults 0swaps
After:
21.50user 1.25system 0:22.76elapsed 99%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+828040outputs (0major+104408minor)pagefaults 0swaps
While the runtime stayed relatively the same, the number of minor page
faults went down significantly.
Signed-off-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The implementation is also lightly modified to use is_dir_sep()
instead of hardcoding '/'.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
[jc: later NUL termination by the caller becomes unnecessary]
Signed-off-by: Ilari Liusvaara <ilari.liusvaara@elisanet.fi>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As the documentation says, this is primarily for debugging, and
in the longer term we should rename it to test-show-index or something.
In the meantime, just avoid xmalloc (which slurps in the rest of git), and
separating out the trivial hex functions into "hex.o".
This results in
[torvalds@nehalem git]$ size git-show-index
text data bss dec hex filename
222818 2276 112688 337782 52776 git-show-index (before)
5696 624 1264 7584 1da0 git-show-index (after)
which is a whole lot better.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The loop in get_size_from_delta() feeds a deflated delta data from the
pack stream _until_ we get inflated result of 20 bytes[*] or we reach the
end of stream.
Side note. This magic number 20 does not have anything to do with the
size of the hash we use, but comes from 1a3b55c (reduce delta head
inflated size, 2006-10-18).
The loop reads like this:
do {
in = use_pack();
stream.next_in = in;
st = git_inflate(&stream, Z_FINISH);
curpos += stream.next_in - in;
} while ((st == Z_OK || st == Z_BUF_ERROR) &&
stream.total_out < sizeof(delta_head));
This git_inflate() can return:
- Z_STREAM_END, if use_pack() fed it enough input and the delta itself
was smaller than 20 bytes;
- Z_OK, when some progress has been made;
- Z_BUF_ERROR, if no progress is possible, because we either ran out of
input (due to corrupt pack), or we ran out of output before we saw the
end of the stream.
The fix b3118bd (sha1_file: Fix infinite loop when pack is corrupted,
2009-10-14) attempted was against a corruption that appears to be a valid
stream that produces a result larger than the output buffer, but we are
not even trying to read the stream to the end in this loop. If avail_out
becomes zero, total_out will be the same as sizeof(delta_head) so the loop
will terminate without the "fix". There is no fix from b3118bd needed for
this loop, in other words.
The loop in unpack_compressed_entry() is quite a different story. It
feeds a deflated stream (either delta or base) and allows the stream to
produce output up to what we expect but no more.
do {
in = use_pack();
stream.next_in = in;
st = git_inflate(&stream, Z_FINISH);
curpos += stream.next_in - in;
} while (st == Z_OK || st == Z_BUF_ERROR)
This _does_ risk falling into an endless interation, as we can exhaust
avail_out if the length we expect is smaller than what the stream wants to
produce (due to pack corruption). In such a case, avail_out will become
zero and inflate() will return Z_BUF_ERROR, while avail_in may (or may
not) be zero.
But this is not a right fix:
do {
in = use_pack();
stream.next_in = in;
st = git_inflate(&stream, Z_FINISH);
+ if (st == Z_BUF_ERROR && (stream.avail_in || !stream.avail_out)
+ break; /* wants more input??? */
curpos += stream.next_in - in;
} while (st == Z_OK || st == Z_BUF_ERROR)
as Z_BUF_ERROR from inflate() may be telling us that avail_in has also run
out before reading the end of stream marker. In such a case, both avail_in
and avail_out would be zero, and the loop should iterate to allow the end
of stream marker to be seen by inflate from the input stream.
The right fix for this loop is likely to be to increment the initial
avail_out by one (we allocate one extra byte to terminate it with NUL
anyway, so there is no risk to overrun the buffer), and break out if we
see that avail_out has become zero, in order to detect that the stream
wants to produce more than what we expect. After the loop, we have a
check that exactly tests this condition:
if ((st != Z_STREAM_END) || stream.total_out != size) {
free(buffer);
return NULL;
}
So here is a patch (without my previous botched attempts) to fix this
issue. The first hunk reverts the corresponding hunk from b3118bd, and
the second hunk is the same fix proposed earlier.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Some types of corruption to a pack may confuse the deflate stream
which stores an object. In Andy's reported case a 36 byte region
of the pack was overwritten, leading to what appeared to be a valid
deflate stream that was trying to produce a result larger than our
allocated output buffer could accept.
Z_BUF_ERROR is returned from inflate() if either the input buffer
needs more input bytes, or the output buffer has run out of space.
Previously we only considered the former case, as it meant we needed
to move the stream's input buffer to the next window in the pack.
We now abort the loop if inflate() returns Z_BUF_ERROR without
consuming the entire input buffer it was given, or has filled
the entire output buffer but has not yet returned Z_STREAM_END.
Either state is a clear indicator that this loop is not working
as expected, and should not continue.
This problem cannot occur with loose objects as we open the entire
loose object as a single buffer and treat Z_BUF_ERROR as an error.
Reported-by: Andy Isaacson <adi@hexapodia.org>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* cc/replace:
t6050: check pushing something based on a replaced commit
Documentation: add documentation for "git replace"
Add git-replace to .gitignore
builtin-replace: use "usage_msg_opt" to give better error messages
parse-options: add new function "usage_msg_opt"
builtin-replace: teach "git replace" to actually replace
Add new "git replace" command
environment: add global variable to disable replacement
mktag: call "check_sha1_signature" with the replacement sha1
replace_object: add a test case
object: call "check_sha1_signature" with the replacement sha1
sha1_file: add a "read_sha1_file_repl" function
replace_object: add mechanism to replace objects found in "refs/replace/"
refs: add a "for_each_replace_ref" function
* tr/die_errno:
Use die_errno() instead of die() when checking syscalls
Convert existing die(..., strerror(errno)) to die_errno()
die_errno(): double % in strerror() output just in case
Introduce die_errno() that appends strerror(errno) to die()
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>
Shifting 'unsigned char' or 'unsigned short' left can result in sign
extension errors, since the C integer promotion rules means that the
unsigned char/short will get implicitly promoted to a signed 'int' due to
the shift (or due to other operations).
This normally doesn't matter, but if you shift things up sufficiently, it
will now set the sign bit in 'int', and a subsequent cast to a bigger type
(eg 'long' or 'unsigned long') will now sign-extend the value despite the
original expression being unsigned.
One example of this would be something like
unsigned long size;
unsigned char c;
size += c << 24;
where despite all the variables being unsigned, 'c << 24' ends up being a
signed entity, and will get sign-extended when then doing the addition in
an 'unsigned long' type.
Since git uses 'unsigned char' pointers extensively, we actually have this
bug in a couple of places.
I may have missed some, but this is the result of looking at
git grep '[^0-9 ][ ]*<<[ ][a-z]' -- '*.c' '*.h'
git grep '<<[ ]*24'
which catches at least the common byte cases (shifting variables by a
variable amount, and shifting by 24 bits).
I also grepped for just 'unsigned char' variables in general, and
converted the ones that most obviously ended up getting implicitly cast
immediately anyway (eg hash_name(), encode_85()).
In addition to just avoiding 'unsigned char', this patch also tries to use
a common idiom for the delta header size thing. We had three different
variations on it: "& 0x7fUL" in one place (getting the sign extension
right), and "& ~0x80" and "& 0x7f" in two other places (not getting it
right). Apart from making them all just avoid using "unsigned char" at
all, I also unified them to then use a simple "& 0x7f".
I considered making a sparse extension which warns about doing implicit
casts from unsigned types to signed types, but it gets rather complex very
quickly, so this is just a hack.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This new function will replace "read_sha1_file". This latter function
becoming just a stub to call the former will a NULL "replacement"
argument.
This new function is needed because sometimes we need to use the
replacement sha1.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The code implementing this mechanism has been copied more-or-less
from the commit graft code.
This mechanism is used in "read_sha1_file". sha1 passed to this
function that match a ref name in "refs/replace/" are replaced by
the sha1 that has been read in the ref.
We "die" if the replacement recursion depth is too high or if we
can't read the replacement object.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* ar/unlink-err:
print unlink(2) errno in copy_or_link_directory
replace direct calls to unlink(2) with unlink_or_warn
Introduce an unlink(2) wrapper which gives warning if unlink failed
* maint:
grep: fix word-regexp colouring
completion: use git rev-parse to detect bare repos
Cope better with a _lot_ of packs
for-each-ref: fix segfault in copy_email
You might end up with a situation where you have tons of pack files, e.g.
when using hg2git. In this situation, all kinds of operations may
end up with a "too many files open" error. Let's recover gracefully from
that.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Looks-right-to-me-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* ar/unlink-err:
print unlink(2) errno in copy_or_link_directory
replace direct calls to unlink(2) with unlink_or_warn
Introduce an unlink(2) wrapper which gives warning if unlink failed
Essentially; s/type* /type */ as per the coding guidelines.
Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This helps to notice when something's going wrong, especially on
systems which lock open files.
I used the following criteria when selecting the code for replacement:
- it was already printing a warning for the unlink failures
- it is in a function which already printing something or is
called from such a function
- it is in a static function, returning void and the function is only
called from a builtin main function (cmd_)
- it is in a function which handles emergency exit (signal handlers)
- it is in a function which is obvously cleaning up the lockfiles
Signed-off-by: Alex Riesen <raa.lkml@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"Unreliable hardlinks" is a misleading description for what is happening.
So rename it to something less misleading.
Suggested by Linus Torvalds.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It seems that accessing NTFS partitions with ufsd (at least on my EeePC)
has an unnerving bug: if you link() a file and unlink() it right away,
the target of the link() will have the correct size, but consist of NULs.
It seems as if the calls are simply not serialized correctly, as single-stepping
through the function move_temp_to_file() works flawlessly.
As ufsd is "Commertial software" (sic!), I cannot fix it, and have to work
around it in Git.
At the same time, it seems that this fixes msysGit issues 222 and 229 to
assume that Windows cannot handle link() && unlink().
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Acked-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* jc/shared-literally:
t1301: loosen test for forced modes
set_shared_perm(): sometimes we know what the final mode bits should look like
move_temp_to_file(): do not forget to chmod() in "Coda hack" codepath
Move chmod(foo, 0444) into move_temp_to_file()
"core.sharedrepository = 0mode" should set, not loosen
* jc/maint-1.6.0-keep-pack:
pack-objects: don't loosen objects available in alternate or kept packs
t7700: demonstrate repack flaw which may loosen objects unnecessarily
Remove --kept-pack-only option and associated infrastructure
pack-objects: only repack or loosen objects residing in "local" packs
git-repack.sh: don't use --kept-pack-only option to pack-objects
t7700-repack: add two new tests demonstrating repacking flaws
Conflicts:
t/t7700-repack.sh
adjust_shared_perm() first obtains the mode bits from lstat(2), expecting
to find what the result of applying user's umask is, and then tweaks it
as necessary. When the file to be adjusted is created with mkstemp(3),
however, the mode thusly obtained does not have anything to do with user's
umask, and we would need to start from 0444 in such a case and there is no
point running lstat(2) for such a path.
This introduces a new API set_shared_perm() to bypass the lstat(2) and
instead force setting the mode bits to the desired value directly.
adjust_shared_perm() becomes a thin wrapper to the function.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Now move_temp_to_file() is responsible for doing everything that is
necessary to turn a tempfile in $GIT_DIR into its final form, it must make
sure "Coda hack" codepath correctly makes the file read-only.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When writing out a loose object or a pack (index), move_temp_to_file() is
called to finalize the resulting file. These files (loose files and packs)
should all have permission mode 0444 (modulo adjust_shared_perm()).
Therefore, instead of doing chmod(foo, 0444) explicitly from each callsite
(or even forgetting to chmod() at all), do the chmod() call from within
move_temp_to_file().
Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This fixes the behaviour of octal notation to how it is defined in the
documentation, while keeping the traditional "loosen only" semantics
intact for "group" and "everybody".
Three main points of this patch are:
- For an explicit octal notation, the internal shared_repository variable
is set to a negative value, so that we can tell "group" (which is to
"OR" in 0660) and 0660 (which is to "SET" to 0660);
- git-init did not set shared_repository variable early enough to affect
the initial creation of many files, notably copied templates and the
configuration. We set it very early when a command-line option
specifies a custom value.
- Many codepaths create files inside $GIT_DIR by various ways that all
involve mkstemp(), and then call move_temp_to_file() to rename it to
its final destination. We can add adjust_shared_perm() call here; for
the traditional "loosen-only", this would be a no-op for many codepaths
because the mode is already loose enough, but with the new behaviour it
makes a difference.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* maint:
Increase the size of the die/warning buffer to avoid truncation
close_sha1_file(): make it easier to diagnose errors
avoid possible overflow in delta size filtering computation
A bug report with "unable to write sha1 file" made us realize that we do
not have enough information to guess why close() is failing.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This option to pack-objects/rev-list was created to improve the -A and -a
options of repack. It was found to be lacking in that it did not provide
the ability to differentiate between local and non-local kept packs, and
found to be unnecessary since objects residing in local kept packs can be
filtered out by the --honor-pack-keep option.
Signed-off-by: Brandon Casey <casey@nrlssc.navy.mil>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* jc/maint-1.6.0-keep-pack:
is_kept_pack(): final clean-up
Simplify is_kept_pack()
Consolidate ignore_packed logic more
has_sha1_kept_pack(): take "struct rev_info"
has_sha1_pack(): refactor "pretend these packs do not exist" interface
git-repack: resist stray environment variable
Now is_kept_pack() is just a member lookup into a structure, we can write
it as such.
Also rewrite the sole caller of has_sha1_kept_pack() to switch on the
criteria the callee uses (namely, revs->kept_pack_only) between calling
has_sha1_kept_pack() and has_sha1_pack(), so that these two callees do not
have to take a pointer to struct rev_info as an argument.
This removes the header file dependency issue temporarily introduced by
the earlier commit, so we revert changes associated to that as well.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This removes --unpacked=<packfile> parameter from the revision parser, and
rewrites its use in git-repack to pass a single --kept-pack-only option
instead.
The new --kept-pack-only option means just that. When this option is
given, is_kept_pack() that used to say "not on the --unpacked=<packfile>
list" now says "the packfile has corresponding .keep file".
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This refactors three loops that check if a given packfile is on the
ignore_packed list into a function is_kept_pack(). The function returns
false for a pack on the list, and true for a pack not on the list, because
this list is solely used by "git repack" to pass list of packfiles that do
not have corresponding .keep files, i.e. a packfile not on the list is
"kept".
Signed-off-by: Junio C Hamano <gitster@pobox.com>
