eed1fbe73b
The add_pattern() function has a subtle and undocumented gotcha: the
pattern string you pass in must remain valid as long as the pattern_list
is in use (and nor do we take ownership of it). This is easy to get
wrong, causing either subtle bugs (because you free or reuse the string
buffer) or leaks (because you copy the string, but don't track ownership
separately).
All of this "pattern" code was originally the "exclude" mechanism. So
this _usually_ works OK because you add entries in one of two ways:
1. From the command-line (e.g., "--exclude"), in which case we're
pointing to an argv entry which remains valid for the lifetime of
the program.
2. From a file (e.g., ".gitignore"), in which case we read the whole
file into a buffer, attach it to the pattern_list's "filebuf"
entry, then parse the buffer in-place (adding NULs). The strings
point into the filebuf, which is cleaned up when the whole
pattern_list goes away.
But other code, like sparse-checkout, reads individual lines from stdin
and passes them one by one to add_pattern(), leaking each. We could fix
this by refactoring it to take in the whole buffer at once, like (2)
above, and stuff it in "filebuf". But given how subtle the interface is,
let's just fix it to always copy the string.
That seems at first like we'd be wasting extra memory, but we can
mitigate that:
a. The path_pattern struct already uses a FLEXPTR, since we sometimes
make a copy (when we see "foo/", we strip off the trailing slash,
requiring a modifiable copy of the string).
Since we'll now always embed the string inside the struct, we can
switch to the regular FLEX_ARRAY pattern, saving us 8 bytes of
pointer. So patterns with a trailing slash and ones under 8 bytes
actually get smaller.
b. Now that we don't need the original string to hang around, we can
get rid of the "filebuf" mechanism entirely, and just free the file
contents after parsing. Since files are the sources we'd expect to
have the largest pattern sets, we should mostly break even on
stuffing the same data into the individual structs.
This patch just adjusts the add_pattern() interface; it doesn't fix any
leaky callers yet.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Git - fast, scalable, distributed revision control system
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.
Many Git online resources are accessible from https://git-scm.com/ including full documentation and Git related tools.
See Documentation/gittutorial.txt to get started, then see
Documentation/giteveryday.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).
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 and Documentation/CodingGuidelines).
Those wishing to help with error message, usage and informational message
string translations (localization l10) should see po/README.md
(a po file is a Portable Object file that holds the translations).
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Issues which are security relevant should be disclosed privately to the Git Security mailing list git-security@googlegroups.com.
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.
The name "git" was given by Linus Torvalds when he wrote the very first version. He described the tool as "the stupid content tracker" and the name as (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