d38379ece9
Since "git update-server-info" may be called automatically
as part of a push or a "gc --auto", we should be robust
against two processes trying to update it simultaneously.
However, we currently use a fixed tempfile, which means that
two simultaneous writers may step on each other's toes and
end up renaming junk into place.
Let's instead switch to using a unique tempfile via mkstemp.
We do not want to use a lockfile here, because it's OK for
two writers to simultaneously update (one will "win" the
rename race, but that's OK; they should be writing the same
information).
While we're there, let's clean up a few other things:
1. Detect write errors. Report them and abort the update
if any are found.
2. Free path memory rather than leaking it (and clean up
the tempfile when necessary).
3. Use the pathdup functions consistently rather than
static buffers or manually calculated lengths.
This last one fixes a potential overflow of "infofile" in
update_info_packs (e.g., by putting large junk into
$GIT_OBJECT_DIRECTORY). However, this overflow was probably
not an interesting attack vector for two reasons:
a. The attacker would need to control the environment to
do this, in which case it was already game-over.
b. During its setup phase, git checks that the directory
actually exists, which means it is probably shorter
than PATH_MAX anyway.
Because both update_info_refs and update_info_packs share
these same failings (and largely duplicate each other), this
patch factors out the improved error-checking version into a
helper function.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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Git - the stupid content tracker
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"git" can mean anything, depending on your mood.
- random three-letter combination that is pronounceable, and not
actually used by any common UNIX command. The fact that it is a
mispronunciation of "get" may or may not be relevant.
- stupid. contemptible and despicable. simple. Take your pick from the
dictionary of slang.
- "global information tracker": you're in a good mood, and it actually
works for you. Angels sing, and a light suddenly fills the room.
- "goddamn idiotic truckload of sh*t": when it breaks
Git is a fast, scalable, distributed revision control system with an
unusually rich command set that provides both high-level operations
and full access to internals.
Git is an Open Source project covered by the GNU General Public
License version 2 (some parts of it are under different licenses,
compatible with the GPLv2). It was originally written by Linus
Torvalds with help of a group of hackers around the net.
Please read the file INSTALL for installation instructions.
See Documentation/gittutorial.txt to get started, then see
Documentation/everyday.txt for a useful minimum set of commands, and
Documentation/git-commandname.txt for documentation of each command.
If git has been correctly installed, then the tutorial can also be
read with "man gittutorial" or "git help tutorial", and the
documentation of each command with "man git-commandname" or "git help
commandname".
CVS users may also want to read Documentation/gitcvs-migration.txt
("man gitcvs-migration" or "git help cvs-migration" if git is
installed).
Many Git online resources are accessible from http://git-scm.com/
including full documentation and Git related tools.
The user discussion and development of Git take place on the Git
mailing list -- everyone is welcome to post bug reports, feature
requests, comments and patches to git@vger.kernel.org (read
Documentation/SubmittingPatches for instructions on patch submission).
To subscribe to the list, send an email with just "subscribe git" in
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The maintainer frequently sends the "What's cooking" reports that
list the current status of various development topics to the mailing
list. The discussion following them give a good reference for
project status, development direction and remaining tasks.