When http-backend spawns "upload-pack" to do ref
negotiation, it streams the http request body to
upload-pack, who then streams the http response back to the
client as it reads. In theory, git can go full-duplex; the
client can consume our response while it is still sending
the request. In practice, however, HTTP is a half-duplex
protocol. Even if our client is ready to read and write
simultaneously, we may have other HTTP infrastructure in the
way, including the webserver that spawns our CGI, or any
intermediate proxies.
In at least one documented case[1], this leads to deadlock
when trying a fetch over http. What happens is basically:
1. Apache proxies the request to the CGI, http-backend.
2. http-backend gzip-inflates the data and sends
the result to upload-pack.
3. upload-pack acts on the data and generates output over
the pipe back to Apache. Apache isn't reading because
it's busy writing (step 1).
This works fine most of the time, because the upload-pack
output ends up in a system pipe buffer, and Apache reads
it as soon as it finishes writing. But if both the request
and the response exceed the system pipe buffer size, then we
deadlock (Apache blocks writing to http-backend,
http-backend blocks writing to upload-pack, and upload-pack
blocks writing to Apache).
We need to break the deadlock by spooling either the input
or the output. In this case, it's ideal to spool the input,
because Apache does not start reading either stdout _or_
stderr until we have consumed all of the input. So until we
do so, we cannot even get an error message out to the
client.
The solution is fairly straight-forward: we read the request
body into an in-memory buffer in http-backend, freeing up
Apache, and then feed the data ourselves to upload-pack. But
there are a few important things to note:
1. We limit the in-memory buffer to prevent an obvious
denial-of-service attack. This is a new hard limit on
requests, but it's unlikely to come into play. The
default value is 10MB, which covers even the ridiculous
100,000-ref negotation in the included test (that
actually caps out just over 5MB). But it's configurable
on the off chance that you don't mind spending some
extra memory to make even ridiculous requests work.
2. We must take care only to buffer when we have to. For
pushes, the incoming packfile may be of arbitrary
size, and we should connect the input directly to
receive-pack. There's no deadlock problem here, though,
because we do not produce any output until the whole
packfile has been read.
For upload-pack's initial ref advertisement, we
similarly do not need to buffer. Even though we may
generate a lot of output, there is no request body at
all (i.e., it is a GET, not a POST).
[1] http://article.gmane.org/gmane.comp.version-control.git/269020
Test-adapted-from: Dennis Kaarsemaker <dennis@kaarsemaker.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git config --get-color" did not parse its command line arguments
carefully.
* jk/colors-fix:
t4026: test "normal" color
config: fix parsing of "git config --get-color some.key -1"
docs: describe ANSI 256-color mode
The point of disallowing ".git" in the index is that we
would never want to accidentally overwrite files in the
repository directory. But this means we need to respect the
filesystem's idea of when two paths are equal. The prior
commit added a helper to make such a comparison for NTFS
and FAT32; let's use it in verify_path().
We make this check optional for two reasons:
1. It restricts the set of allowable filenames, which is
unnecessary for people who are not on NTFS nor FAT32.
In practice this probably doesn't matter, though, as
the restricted names are rather obscure and almost
certainly would never come up in practice.
2. It has a minor performance penalty for every path we
insert into the index.
This patch ties the check to the core.protectNTFS config
option. Though this is expected to be most useful on Windows,
we allow it to be set everywhere, as NTFS may be mounted on
other platforms. The variable does default to on for Windows,
though.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The point of disallowing ".git" in the index is that we
would never want to accidentally overwrite files in the
repository directory. But this means we need to respect the
filesystem's idea of when two paths are equal. The prior
commit added a helper to make such a comparison for HFS+;
let's use it in verify_path.
We make this check optional for two reasons:
1. It restricts the set of allowable filenames, which is
unnecessary for people who are not on HFS+. In practice
this probably doesn't matter, though, as the restricted
names are rather obscure and almost certainly would
never come up in practice.
2. It has a minor performance penalty for every path we
insert into the index.
This patch ties the check to the core.protectHFS config
option. Though this is expected to be most useful on OS X,
we allow it to be set everywhere, as HFS+ may be mounted on
other platforms. The variable does default to on for OS X,
though.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Our color specifications have supported the 256-color ANSI
extension for years, but we never documented it.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The git-push manual page used "gitlink" in one place instead of
"linkgit". Fix this so the link renders correctly.
Noticed-by: Dan Allen <dan.j.allen@gmail.com>
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
'git status' doesn't output leading '#'s these days.
Signed-off-by: Stefan Naewe <stefan.naewe@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In an earlier part there is:
"re-send it with "To:" set to the maintainer [*1*] and "cc:" the list [*2*]"
for the final submission, but later we see
"Send it to the list and cc the maintainer."
Fix the later one to match the previous.
Signed-off-by: Slavomir Vlcek <svlc@inventati.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In particular, git-fast-import and -export link to each
other, and gitremote-helpers links to existing remote
helpers, and vice versa. Also link to fast-import from the
remote helper spec, as this is relevant for remote helpers
using the fast-import format.
Signed-off-by: Max Horn <max@quendi.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a missing article at the beginning of a sentence, and rephrase
slightly.
Signed-off-by: Thomas Quinot <thomas@quinot.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
With the original phrasing, it is possible to misunderstand as if
the contents in the index for only the specified paths are made into
the new commit.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The option name "--store" was used early in development, but
never even made it into an applied patch, let alone a
released version of git. I forgot to update the matching
documentation at the time, though.
Noticed-by: Jesse Hopkins <jesse.hopkins@lmco.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In addition to fixing trivial and obvious typos, be careful about
the following points:
- Spell ASCII, URL and CRC in ALL CAPS;
- Spell Linux as Capitalized;
- Do not omit periods in "i.e." and "e.g.".
Signed-off-by: Thomas Ackermann <th.acker@arcor.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
* 'for-junio' of git://bogomips.org/git-svn:
git-svn: use SVN::Ra::get_dir2 when possible
git-svn: add space after "W:" prefix in warning
git-svn: (cleanup) remove editor param passing
git-svn: prepare SVN::Ra config pieces once
Git.pm: add specified name to tempfile template
git-svn: disable _rev_list memoization
git-svn: save a little memory as fetch progresses
git-svn: remove unnecessary DESTROY override
git-svn: reload RA every log-window-size
git-svn.txt: advertise pushurl with dcommit
git-svn: remove mergeinfo rev caching
git-svn: cache only mergeinfo revisions
git-svn: reduce check_cherry_pick cache overhead
git-svn: only look at the root path for svn:mergeinfo
git-svn: only look at the new parts of svn:mergeinfo
Allow painting or not painting (partial) matches in context lines
when showing "grep -C<num>" output in color.
* rs/grep-color-words:
grep: add color.grep.matchcontext and color.grep.matchselected
