Commit graph

27 commits

Author SHA1 Message Date
Jonathan Nieder
1368f65002 compat: helper for detecting unsigned overflow
The idiom (a + b < a) works fine for detecting that an unsigned
integer has overflowed, but a more explicit

	unsigned_add_overflows(a, b)

might be easier to read.

Define such a macro, expanding roughly to ((a) < UINT_MAX - (b)).
Because the expansion uses each argument only once outside of sizeof()
expressions, it is safe to use with arguments that have side effects.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-02-10 13:47:56 -08:00
Junio C Hamano
00b0d7f77b set_try_to_free_routine(NULL) means "do nothing special"
This way, the next caller that wants to disable our memory reclamation
machinery does not have to define its own do_nothing() stub.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-12-21 09:25:14 -08:00
Jonathan Nieder
e050029385 Remove pack file handling dependency from wrapper.o
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>
2010-11-10 11:11:07 -08:00
Jonathan Nieder
b0613ce0f9 wrapper: give zlib wrappers their own translation unit
Programs using xmalloc() but not git_inflate() require -lz on the
linker command line because git_inflate() is in the same translation
unit as xmalloc().

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-11-10 11:07:51 -08:00
Jonathan Nieder
33f239365c path helpers: move git_mkstemp* to wrapper.c
git_mkstemp_mode and related functions do not require access to
specialized git machinery, unlike some other functions from
path.c (like set_shared_perm()).  Move them to wrapper.c where
the wrapper xmkstemp_mode is defined.

This eliminates a dependency of wrapper.o on environment.o via
path.o.  With typical linkers (e.g., gcc), that dependency makes
programs that use functions from wrapper.o and not environment.o
or path.o larger than they need to be.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-11-10 11:04:26 -08:00
Jonathan Nieder
463db9b104 wrapper: move odb_* to environment.c
The odb_mkstemp and odb_pack_keep functions open files under the
$GIT_OBJECT_DIRECTORY directory.  This requires access to the git
configuration which very simple programs do not need.

Move these functions to environment.o, closer to their dependencies.
This should make it easier for programs to link to wrapper.o without
linking to environment.o.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-11-10 11:03:38 -08:00
Jonathan Nieder
58ecbd5ede wrapper: move xmmap() to sha1_file.c
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>
2010-11-10 11:03:13 -08:00
Matthieu Moy
8bd9fd5001 xmalloc: include size in the failure message
Out-of-memory errors can either be actual lack of memory, or bugs (like
code trying to call xmalloc(-1) by mistake). A little more information
may help tracking bugs reported by users.

Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-08-20 09:27:38 -07:00
Junio C Hamano
44e08b003d Merge branch 'js/try-to-free-stackable'
* js/try-to-free-stackable:
  Do not call release_pack_memory in malloc wrappers when GIT_TRACE is used
  Have set_try_to_free_routine return the previous routine
2010-06-13 11:21:21 -07:00
Junio C Hamano
ea5f75a64a Merge branch 'np/malloc-threading'
* np/malloc-threading:
  Thread-safe xmalloc and xrealloc needs a recursive mutex
  Make xmalloc and xrealloc thread-safe
2010-05-21 04:02:16 -07:00
Johannes Sixt
851c34b04e Have set_try_to_free_routine return the previous routine
This effectively requires from the callers of set_try_to_free_routine to
treat the try-to-free-routines as a stack.

We will need this for the next patch where the only current caller cannot
depend on that the previously set routine was the default routine.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-05-08 22:27:54 -07:00
Peter Collingbourne
80d706afed Introduce remove_or_warn function
This patch introduces the remove_or_warn function which is a
generalised version of the {unlink,rmdir}_or_warn functions.  It takes
an additional parameter indicating the mode of the file to be removed.

The patch also modifies certain functions to use remove_or_warn
where appropriate, and adds a test case for a bug fixed by the use
of remove_or_warn.

Signed-off-by: Peter Collingbourne <peter@pcc.me.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-03-28 09:53:04 -07:00
Peter Collingbourne
d1723296af Implement the rmdir_or_warn function
This patch implements an rmdir_or_warn function (like unlink_or_warn
but for directories) that uses the generalised warning code in
warn_if_unremovable.

Signed-off-by: Peter Collingbourne <peter@pcc.me.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-03-28 09:53:01 -07:00
Peter Collingbourne
10e13ec8ed Generalise the unlink_or_warn function
This patch moves the warning code of the unlink_or_warn function into
a separate function named warn_if_unremovable so that it may be reused.

Signed-off-by: Peter Collingbourne <peter@pcc.me.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-03-28 09:52:59 -07:00
Nicolas Pitre
a9a746364b Make xmalloc and xrealloc thread-safe
By providing a hook for the routine responsible for trying to free some
memory on malloc failure, we can ensure that the  called routine is
protected by the appropriate locks when threads are in play.

The obvious offender here was pack-objects which was calling xmalloc()
within threads while release_pack_memory() is not thread safe.

Signed-off-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-03-24 14:15:09 -07:00
Matthieu Moy
f80c7ae8fe Use git_mkstemp_mode and xmkstemp_mode in odb_mkstemp, not chmod later.
We used to create 0600 files, and then use chmod to set the group and
other permission bits to the umask. This usually has the same effect
as a normal file creation with a umask.

But in the presence of ACLs, the group permission plays the role of
the ACL mask: the "g" bits of newly created files are chosen according
to default ACL mask of the directory, not according to the umask, and
doing a chmod() on these "g" bits affect the ACL's mask instead of
actual group permission.

In other words, creating files with 0600 and then doing a chmod to the
umask creates files which are unreadable by users allowed in the
default ACL. To create the files without breaking ACLs, we let the
umask do it's job at the file's creation time, and get rid of the
later chmod.

Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-02-22 15:24:46 -08:00
Matthieu Moy
b862b61c03 git_mkstemp_mode, xmkstemp_mode: variants of gitmkstemps with mode argument.
gitmkstemps emulates the behavior of mkstemps, which is usually used
to create files in a shared directory like /tmp/, hence, it creates
files with permission 0600.

Add git_mkstemps_mode() that allows us to specify the desired mode, and
make git_mkstemps() a wrapper that always uses 0600 to call it. Later we
will use git_mkstemps_mode() when creating pack files.

Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-02-22 15:24:45 -08:00
Ilari Liusvaara
5bf9219d01 Add xmallocz()
Add routine for allocating NUL-terminated memory block without risking
integer overflow in addition of +1 for NUL byte.

[jc: with suggestion from Bill Lear]

Signed-off-by: Ilari Liusvaara <ilari.liusvaara@elisanet.fi>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-01-26 12:57:53 -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
Alex Riesen
fc71db39e0 Introduce an unlink(2) wrapper which gives warning if unlink failed
This seem to be a very common pattern in the current code.

The function prints a generic removal failure message, the file name
which failed and readable errno presentation. The function preserves
errno and always returns the value unlink(2) returned, but prints
no message for ENOENT, as it was the most often filtered out in the
code calling unlink. Besides, removing a file is anyway the purpose of
calling unlink.

Signed-off-by: Alex Riesen <raa.lkml@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-04-29 18:37:41 -07:00
Junio C Hamano
f474c52661 Merge branch 'jc/maint-1.6.0-pack-directory'
* jc/maint-1.6.0-pack-directory:
  Fix odb_mkstemp() on AIX
2009-02-28 16:31:02 -08:00
Mike Ralphson
2c626e5fa8 Fix odb_mkstemp() on AIX
The AIX mkstemp() modifies its template parameter to an empty string if
the call fails.  The existing code had already recomputed the template,
but too late to be good.

See also 6ff6af62, which fixed this problem in a different spot.

Signed-off-by: Mike Ralphson <mike@abacus.co.uk>
Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-02-26 08:40:27 -08:00
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
Linus Torvalds
39c68542fc Wrap inflate and other zlib routines for better error reporting
R. Tyler Ballance reported a mysterious transient repository corruption;
after much digging, it turns out that we were not catching and reporting
memory allocation errors from some calls we make to zlib.

This one _just_ wraps things; it doesn't do the "retry on low memory
error" part, at least not yet. It is an independent issue from the
reporting.  Some of the errors are expected and passed back to the caller,
but we die when zlib reports it failed to allocate memory for now.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-01-11 02:13:06 -08:00
Junio C Hamano
559e840b74 Move read_in_full() and write_in_full() to wrapper.c
A few compat/* layer functions call these functions, but we would really
want to keep them thin, without depending too much on the libgit proper.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-20 17:17:09 -07:00
Linus Torvalds
112db553b0 Shrink the git binary a bit by avoiding unnecessary inline functions
So I was looking at the disgusting size of the git binary, and even with
the debugging removed, and using -Os instead of -O2, the size of the text
section was pretty high. In this day and age I guess almost a megabyte of
text isn't really all that surprising, but it still doesn't exactly make
me think "lean and mean".

With -Os, a surprising amount of text space is wasted on inline functions
that end up just being replicated multiple times, and where performance
really isn't a valid reason to inline them. In particular, the trivial
wrapper functions like "xmalloc()" are used _everywhere_, and making them
inline just duplicates the text (and the string we use to 'die()' on
failure) unnecessarily.

So this just moves them into a "wrapper.c" file, getting rid of a tiny bit
of unnecessary bloat. The following numbers are both with "CFLAGS=-Os":

Before:
	[torvalds@woody git]$ size git
	   text	   data	    bss	    dec	    hex	filename
	 700460	  15160	 292184	1007804	  f60bc	git

After:
	[torvalds@woody git]$ size git
	   text	   data	    bss	    dec	    hex	filename
	 670540	  15160	 292184	 977884	  eebdc	git

so it saves almost 30k of text-space (it actually saves more than that
with the default -O2, but I don't think that's necessarily a very relevant
number from a "try to shrink git" standpoint).

It might conceivably have a performance impact, but none of this should be
_that_ performance critical. The real cost is not generally in the wrapper
anyway, but in the code it wraps (ie the cost of "xread()" is all in the
read itself, not in the trivial wrapping of it).

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-06-22 18:46:00 -07:00