Git with broken hash generation to generate collisions between object IDs. Don't use this! https://undefinedbehavior.de/posts/commit-vandalism/
Go to file
Johannes Schindelin 116d1fa6c6 vreportf(): avoid relying on stdio buffering
The MSVC runtime behavior differs from glibc's with respect to
`fprintf(stderr, ...)` in that the former writes out the message
character by character.

In t5516, this leads to a funny problem where a `git fetch` process as
well as the `git upload-pack` process spawned by it _both_ call `die()`
at the same time. The output can look like this:

	fatal: git uploadfata-lp: raemcokte :error:  upload-pnot our arcef k6: n4ot our ea4cr1e3f 36d45ea94fca1398e86a771eda009872d63adb28598f6a9
	8e86a771eda009872d6ab2886

Let's avoid this predicament altogether by rendering the entire message,
including the prefix and the trailing newline, into the buffer we
already have (and which is still fixed size) and then write it out via
`write_in_full()`.

We still clip the message to at most 4095 characters.

The history of `vreportf()` with regard to this issue includes the
following commits:

d048a96e (2007-11-09) - 'char msg[256]' is introduced to avoid interleaving
389d1767 (2009-03-25) - Buffer size increased to 1024 to avoid truncation
625a860c (2009-11-22) - Buffer size increased to 4096 to avoid truncation
f4c3edc0 (2015-08-11) - Buffer removed to avoid truncation
b5a9e435 (2017-01-11) - Reverts f4c3edc0 to be able to replace control
                        chars before sending to stderr
9ac13ec9 (2006-10-11) - Another attempt to solve interleaving.
                        This is seemingly related to d048a96e.
137a0d0e (2007-11-19) - Addresses out-of-order for display()
34df8aba (2009-03-10) - Switches xwrite() to fprintf() in recv_sideband()
                        to support UTF-8 emulation
eac14f89 (2012-01-14) - Removes the need for fprintf() for UTF-8 emulation,
                        so it's safe to use xwrite() again
5e5be9e2 (2016-06-28) - recv_sideband() uses xwrite() again

Note that we print nothing if the `vsnprintf()` call failed to render
the error message; There is little we can do in that case, and it should
not happen anyway.

The process may have written to `stderr` and there may be something left
in the buffer kept in the stdio layer. Call `fflush(stderr)` before
writing the message we prepare in this function.

Helped-by: Jeff King <peff@peff.net>
Helped-by: Alexandr Miloslavskiy <alexandr.miloslavskiy@syntevo.com>
Helped-by: SZEDER Gábor <szeder.dev@gmail.com>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-02 15:20:21 +09:00
.github
block-sha1
builtin Merge branch 'jk/no-system-includes-in-dot-c' into maint 2019-08-09 15:18:19 -07:00
ci Merge branch 'sg/travis-gcc-4.8' 2019-07-29 12:39:13 -07:00
compat Merge branch 'js/visual-studio' 2019-08-02 13:12:02 -07:00
contrib Merge branch 'js/visual-studio' 2019-08-02 13:12:02 -07:00
Documentation Git 2.22.1 2019-08-11 17:41:39 -07:00
ewah
git-gui
gitk-git
gitweb
mergetools
negotiator
perl
po l10n: zh_CN: for git v2.23.0 l10n round 1~2 2019-08-16 16:59:17 +08:00
ppc
refs dir-iterator: release strbuf after use 2019-08-07 12:25:35 -07:00
sha1collisiondetection@855827c583
sha1dc
sha256
t Merge branch 'jk/xdiff-clamp-funcname-context-index' into maint 2019-08-09 15:18:18 -07:00
templates
trace2
vcs-svn *.[ch]: manually align parameter lists 2019-05-05 15:20:10 +09:00
xdiff Merge branch 'cb/xdiff-no-system-includes-in-dot-c' into maint 2019-08-09 15:18:19 -07:00
.clang-format
.editorconfig
.gitattributes Mark .bat files as requiring CR/LF endings 2019-06-20 14:03:05 -07:00
.gitignore Merge branch 'js/visual-studio' 2019-08-02 13:12:02 -07:00
.gitmodules
.mailmap .mailmap: update email address of Philip Oakley 2019-08-11 15:07:51 -07:00
.travis.yml travis-ci: build with GCC 4.8 as well 2019-07-19 14:06:01 -07:00
.tsan-suppressions
abspath.c
aclocal.m4
advice.c Merge branch 'ra/cherry-pick-revert-skip' 2019-07-19 11:30:21 -07:00
advice.h Merge branch 'ra/cherry-pick-revert-skip' 2019-07-19 11:30:21 -07:00
alias.c alias.c: mark split_cmdline_strerror() strings for translation 2018-11-12 14:47:09 +09:00
alias.h
alloc.c
alloc.h
apply.c apply: make parse_git_diff_header public 2019-07-11 14:29:27 -07:00
apply.h apply: make parse_git_diff_header public 2019-07-11 14:29:27 -07:00
archive-tar.c
archive-zip.c
archive.c tree-walk.c: remove the_repo from get_tree_entry() 2019-06-27 12:45:17 -07:00
archive.h
argv-array.c
argv-array.h
attr.c
attr.h
azure-pipelines.yml
banned.h
base85.c
bisect.c bisect: make diff-tree output prettier 2019-03-01 07:31:38 +09:00
bisect.h
blame.c Merge branch 'nd/tree-walk-with-repo' 2019-07-19 11:30:21 -07:00
blame.h Merge branch 'br/blame-ignore' 2019-07-19 11:30:20 -07:00
blob.c object: convert create_object() to use object_id 2019-06-20 10:20:51 -07:00
blob.h
branch.c Merge branch 'nd/switch-and-restore' 2019-07-09 15:25:44 -07:00
branch.h Merge branch 'nd/switch-and-restore' 2019-07-09 15:25:44 -07:00
builtin.h Merge branch 'ab/test-env' 2019-07-25 13:59:20 -07:00
bulk-checkin.c
bulk-checkin.h
bundle.c
bundle.h
cache-tree.c cache-tree/blame: avoid reusing the DEBUG constant 2019-06-20 14:03:05 -07:00
cache-tree.h
cache.h Merge branch 'sg/rebase-progress' into maint 2019-07-29 12:38:19 -07:00
chdir-notify.c
chdir-notify.h
check_bindir
check-builtins.sh
checkout.c
checkout.h
color.c
color.h
column.c
column.h *.[ch]: manually align parameter lists 2019-05-05 15:20:10 +09:00
combine-diff.c
command-list.txt
commit-graph.c Merge branch 'ds/commit-graph-incremental' 2019-08-09 10:13:13 -07:00
commit-graph.h commit-graph: verify chains with --shallow mode 2019-06-19 20:46:26 -07:00
commit-reach.c
commit-reach.h
commit-slab-decl.h
commit-slab-impl.h
commit-slab.h
commit.c Merge branch 'ds/close-object-store' into maint 2019-07-29 12:38:22 -07:00
commit.h
common-main.c
config.c config: work around bug with includeif:onbranch and early config 2019-07-31 15:20:56 -07:00
config.h
config.mak.dev
config.mak.in
config.mak.uname vcxproj: also link-or-copy builtins 2019-07-29 14:51:43 -07:00
configure.ac
connect.c
connect.h
connected.c check_everything_connected: assume alternate ref tips are valid 2019-07-01 10:11:09 -07:00
connected.h
convert.c
convert.h
copy.c
COPYING
credential-cache--daemon.c
credential-cache.c
credential-store.c
credential.c
credential.h
csum-file.c
csum-file.h
ctype.c
daemon.c
date.c
decorate.c hashmap: convert sha1hash() to oidhash() 2019-06-20 10:44:22 -07:00
decorate.h
delta-islands.c Merge branch 'jk/oidhash' 2019-07-09 15:25:43 -07:00
delta-islands.h delta-islands: respect progress flag 2019-06-20 13:29:49 -07:00
delta.h
detect-compiler
diff-delta.c
diff-lib.c
diff-no-index.c
diff.c Merge branch 'js/unmap-before-ext-diff' into maint 2019-07-29 12:38:11 -07:00
diff.h range-diff: suppress line count in outer diff 2019-07-11 14:29:27 -07:00
diffcore-break.c
diffcore-delta.c
diffcore-order.c
diffcore-pickaxe.c
diffcore-rename.c Merge branch 'jk/oidhash' 2019-07-09 15:25:43 -07:00
diffcore.h
dir-iterator.c dir-iterator: add flags parameter to dir_iterator_begin 2019-07-11 13:52:15 -07:00
dir-iterator.h dir-iterator: add flags parameter to dir_iterator_begin 2019-07-11 13:52:15 -07:00
dir.c
dir.h
editor.c pager: add a helper function to clear the last line in the terminal 2019-06-24 13:38:46 -07:00
entry.c
environment.c
exec-cmd.c
exec-cmd.h
fast-import.c Merge branch 'nd/tree-walk-with-repo' 2019-07-19 11:30:21 -07:00
fetch-negotiator.c
fetch-negotiator.h
fetch-object.c
fetch-object.h
fetch-pack.c Merge branch 'nd/fetch-capability-tweak' 2019-07-09 15:25:43 -07:00
fetch-pack.h
fmt-merge-msg.h
fsck.c Merge branch 'br/blame-ignore' 2019-07-19 11:30:20 -07:00
fsck.h
fsmonitor.c Merge branch 'cb/fsmonitor-intfix' into maint 2019-07-29 12:38:15 -07:00
fsmonitor.h
fuzz-commit-graph.c
fuzz-pack-headers.c
fuzz-pack-idx.c
generate-cmdlist.sh
gettext.c Merge branch 'ab/test-env' 2019-07-25 13:59:20 -07:00
gettext.h
git-add--interactive.perl Merge branch 'pw/add-p-recount' into maint 2019-07-29 12:38:22 -07:00
git-archimport.perl
git-bisect.sh
git-compat-util.h msvc: add a compile-time flag to allow detailed heap debugging 2019-06-25 10:46:57 -07:00
git-cvsexportcommit.perl
git-cvsimport.perl
git-cvsserver.perl
git-difftool--helper.sh
git-filter-branch.sh
git-instaweb.sh
git-legacy-stash.sh
git-merge-octopus.sh
git-merge-one-file.sh
git-merge-resolve.sh
git-mergetool--lib.sh
git-mergetool.sh
git-p4.py Merge branch 'sw/git-p4-unshelve-branched-files' into maint 2019-07-25 14:27:15 -07:00
git-parse-remote.sh
git-quiltimport.sh
git-rebase--preserve-merges.sh
git-request-pull.sh
git-send-email.perl
git-sh-i18n.sh tests: make GIT_TEST_GETTEXT_POISON a boolean 2019-06-21 09:42:49 -07:00
git-sh-setup.sh
git-submodule.sh
git-svn.perl
GIT-VERSION-GEN Git 2.23 2019-08-16 10:28:23 -07:00
git-web--browse.sh
git.c Merge branch 'js/visual-studio' 2019-08-02 13:12:02 -07:00
git.rc mingw: embed a manifest to trick UAC into Doing The Right Thing 2019-06-27 12:55:45 -07:00
gpg-interface.c gpg-interface: do not scan past the end of buffer 2019-07-16 12:15:12 -07:00
gpg-interface.h
graph.c
graph.h
grep.c Merge branch 'bb/grep-pcre2-bug-message-fix' 2019-07-29 12:39:13 -07:00
grep.h
hash.h hash.h: move object_id definition from cache.h 2019-06-20 10:40:42 -07:00
hashmap.c
hashmap.h hashmap: convert sha1hash() to oidhash() 2019-06-20 10:44:22 -07:00
help.c Merge branch 'jk/help-unknown-ref-fix' 2019-06-13 13:19:42 -07:00
help.h
hex.c
http-backend.c
http-fetch.c
http-push.c object: convert lookup_object() to use object_id 2019-06-20 10:18:09 -07:00
http-walker.c
http.c
http.h
ident.c
imap-send.c
INSTALL
interdiff.c
interdiff.h
iterator.h
json-writer.c
json-writer.h
khash.h hashmap: convert sha1hash() to oidhash() 2019-06-20 10:44:22 -07:00
kwset.c Merge branch 'rs/copy-array' into maint 2019-07-29 12:38:15 -07:00
kwset.h
levenshtein.c
levenshtein.h
LGPL-2.1
line-log.c tree-walk.c: remove the_repo from get_tree_entry() 2019-06-27 12:45:17 -07:00
line-log.h *.[ch]: remove extern from function declarations using spatch 2019-05-05 15:20:06 +09:00
line-range.c
line-range.h
linear-assignment.c
linear-assignment.h
list-objects-filter-options.c Merge branch 'md/list-objects-filter-parse-msgfix' 2019-06-21 11:24:10 -07:00
list-objects-filter-options.h
list-objects-filter.c Merge branch 'md/list-objects-filter-memfix' into maint 2019-07-25 14:27:12 -07:00
list-objects-filter.h
list-objects.c
list-objects.h
list.h
ll-merge.c
ll-merge.h
lockfile.c Replace all die("BUG: ...") calls by BUG() ones 2018-05-06 19:06:13 +09:00
lockfile.h
log-tree.c
log-tree.h
ls-refs.c
ls-refs.h
mailinfo.c
mailinfo.h *.[ch]: remove extern from function declarations using spatch 2019-05-05 15:20:06 +09:00
mailmap.c
mailmap.h
Makefile Merge branch 'js/visual-studio' 2019-08-02 13:12:02 -07:00
match-trees.c match-trees.c: remove the_repo from shift_tree*() 2019-06-27 12:45:17 -07:00
mem-pool.c
mem-pool.h
merge-blobs.c
merge-blobs.h
merge-recursive.c Merge branch 'en/disable-dir-rename-in-recursive-merge' 2019-08-08 14:26:10 -07:00
merge-recursive.h
merge.c
mergesort.c
mergesort.h
midx.c
midx.h
name-hash.c
notes-cache.c
notes-cache.h
notes-merge.c
notes-merge.h
notes-utils.c
notes-utils.h
notes.c tree-walk.c: remove the_repo from get_tree_entry() 2019-06-27 12:45:17 -07:00
notes.h
object-store.h Merge branch 'ds/object-info-for-prefetch-fix' into maint 2019-07-25 14:27:08 -07:00
object.c Merge branch 'jk/oidhash' 2019-07-09 15:25:43 -07:00
object.h object: convert create_object() to use object_id 2019-06-20 10:20:51 -07:00
oidmap.c Merge branch 'cc/test-oidmap' 2019-07-19 11:30:19 -07:00
oidmap.h
oidset.c Merge branch 'br/blame-ignore' 2019-07-19 11:30:20 -07:00
oidset.h Merge branch 'br/blame-ignore' 2019-07-19 11:30:20 -07:00
pack-bitmap-write.c pack-bitmap: convert khash_sha1 maps into kh_oid_map 2019-06-20 10:35:05 -07:00
pack-bitmap.c pack-bitmap: convert khash_sha1 maps into kh_oid_map 2019-06-20 10:35:05 -07:00
pack-bitmap.h pack-bitmap: convert khash_sha1 maps into kh_oid_map 2019-06-20 10:35:05 -07:00
pack-check.c
pack-objects.c hashmap: convert sha1hash() to oidhash() 2019-06-20 10:44:22 -07:00
pack-objects.h pack-objects: convert packlist_find() to use object_id 2019-06-20 09:54:58 -07:00
pack-revindex.c
pack-revindex.h
pack-write.c
pack.h
packfile.c Merge branch 'ds/close-object-store' into maint 2019-07-29 12:38:22 -07:00
packfile.h Merge branch 'ds/close-object-store' into maint 2019-07-29 12:38:22 -07:00
pager.c pager: add a helper function to clear the last line in the terminal 2019-06-24 13:38:46 -07:00
parse-options-cb.c Merge branch 'nd/switch-and-restore' 2019-07-09 15:25:44 -07:00
parse-options.c
parse-options.h Merge branch 'nd/switch-and-restore' 2019-07-09 15:25:44 -07:00
patch-delta.c
patch-ids.c hashmap: convert sha1hash() to oidhash() 2019-06-20 10:44:22 -07:00
patch-ids.h
path.c
path.h
pathspec.c
pathspec.h
pkt-line.c
pkt-line.h
preload-index.c
pretty.c use COPY_ARRAY for copying arrays 2019-06-17 18:15:04 -07:00
pretty.h
prio-queue.c
prio-queue.h
progress.c Merge branch 'dr/progress-i18n' 2019-07-11 15:16:49 -07:00
progress.h
prompt.c
prompt.h
protocol.c
protocol.h
quote.c
quote.h
range-diff.c range-diff: add headers to the outer hunk header 2019-07-11 14:29:27 -07:00
range-diff.h
reachable.c object: convert lookup_object() to use object_id 2019-06-20 10:18:09 -07:00
reachable.h
read-cache.c Merge branch 'rs/avoid-overflow-in-midpoint-computation' into maint 2019-07-29 12:38:21 -07:00
README.md README: fix rendering of text in angle brackets 2019-07-18 14:47:46 -07:00
rebase-interactive.c
rebase-interactive.h
ref-filter.c Merge branch 'ma/ref-filter-leakfix' 2019-07-19 11:30:23 -07:00
ref-filter.h
reflog-walk.c
reflog-walk.h
refs.c object: convert lookup_unknown_object() to use object_id 2019-06-20 10:06:19 -07:00
refs.h
refspec.c
refspec.h
RelNotes Flush fixes up to the third batch post 2.22.0 2019-07-25 14:32:36 -07:00
remote-curl.c i18n: fix typos found during l10n for git 2.22.0 2019-06-03 11:10:53 -07:00
remote-testsvn.c
remote.c
remote.h
replace-object.c
replace-object.h
repository.c
repository.h
rerere.c
rerere.h
resolve-undo.c
resolve-undo.h
revision.c Merge branch 'jk/check-connected-with-alternates' 2019-07-19 11:30:21 -07:00
revision.h
run-command.c
run-command.h
send-pack.c
send-pack.h
sequencer.c Merge branch 'pw/rebase-abort-clean-rewritten' into maint 2019-07-29 12:38:20 -07:00
sequencer.h Merge branch 'ra/cherry-pick-revert-skip' 2019-07-19 11:30:21 -07:00
serve.c
serve.h
server-info.c Merge branch 'ew/server-info-remove-crufts' 2019-06-17 10:15:15 -07:00
setup.c
sh-i18n--envsubst.c
sha1-array.c
sha1-array.h
sha1-file.c sha1-file: release strbuf after use 2019-08-07 12:28:57 -07:00
sha1-lookup.c Replace all die("BUG: ...") calls by BUG() ones 2018-05-06 19:06:13 +09:00
sha1-lookup.h
sha1-name.c Merge branch 'nd/tree-walk-with-repo' 2019-07-19 11:30:21 -07:00
sha1dc_git.c
sha1dc_git.h
shallow.c Use the right 'struct repository' instead of the_repository 2019-06-27 12:45:17 -07:00
shell.c
shortlog.h
sideband.c
sideband.h
sigchain.c
sigchain.h
split-index.c
split-index.h
strbuf.c l10n: localizable upload progress messages 2019-07-02 12:18:49 -07:00
strbuf.h l10n: localizable upload progress messages 2019-07-02 12:18:49 -07:00
streaming.c
streaming.h
string-list.c
string-list.h
sub-process.c
sub-process.h
submodule-config.c
submodule-config.h
submodule.c
submodule.h
symlinks.c
tag.c object: convert create_object() to use object_id 2019-06-20 10:20:51 -07:00
tag.h
tar.h tar-tree: Introduce write_entry() 2006-03-25 16:35:43 -08:00
tempfile.c
tempfile.h
thread-utils.c
thread-utils.h
tmp-objdir.c
tmp-objdir.h
trace2.c
trace2.h
trace.c
trace.h
trailer.c
trailer.h
transport-helper.c Merge branch 'es/local-atomic-push-failure-with-http' into maint 2019-07-29 12:38:16 -07:00
transport-internal.h
transport.c Merge branch 'es/local-atomic-push-failure-with-http' 2019-07-25 13:59:22 -07:00
transport.h object-store.h: move for_each_alternate_ref() from transport.h 2019-07-01 09:47:29 -07:00
tree-diff.c tree-walk.c: remove the_repo from fill_tree_descriptor() 2019-06-27 12:45:17 -07:00
tree-walk.c tree-walk.c: remove the_repo from get_tree_entry_follow_symlinks() 2019-06-27 12:45:17 -07:00
tree-walk.h tree-walk.c: remove the_repo from get_tree_entry_follow_symlinks() 2019-06-27 12:45:17 -07:00
tree.c object: convert create_object() to use object_id 2019-06-20 10:20:51 -07:00
tree.h
unicode-width.h Merge branch 'bb/unicode-12.1-reiwa' into maint 2019-07-25 14:27:11 -07:00
unimplemented.sh
unix-socket.c
unix-socket.h
unpack-trees.c Merge branch 'nd/tree-walk-with-repo' 2019-07-19 11:30:21 -07:00
unpack-trees.h
upload-pack.c Merge branch 'ds/close-object-store' into maint 2019-07-29 12:38:22 -07:00
upload-pack.h
url.c
url.h
urlmatch.c
urlmatch.h
usage.c vreportf(): avoid relying on stdio buffering 2019-11-02 15:20:21 +09:00
userdiff.c Merge branch 'ml/userdiff-rust' 2019-06-21 11:24:08 -07:00
userdiff.h
utf8.c
utf8.h
varint.c
varint.h
version.c
version.h
versioncmp.c
walker.c object: convert lookup_unknown_object() to use object_id 2019-06-20 10:06:19 -07:00
walker.h
wildmatch.c
wildmatch.h
worktree.c Merge branch 'nd/corrupt-worktrees' into maint 2019-07-25 14:27:07 -07:00
worktree.h
wrap-for-bin.sh
wrapper.c wrapper: avoid undefined behaviour in macOS 2019-06-19 07:41:31 -07:00
write-or-die.c
ws.c
wt-status.c Merge branch 'jl/status-reduce-vertical-blank' 2019-07-19 11:30:23 -07:00
wt-status.h Merge branch 'jk/no-system-includes-in-dot-c' 2019-07-31 14:38:56 -07:00
xdiff-interface.c
xdiff-interface.h
zlib.c

Build Status

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). To subscribe to the list, send an email with just "subscribe git" in the body to majordomo@vger.kernel.org. The mailing list archives are available at https://public-inbox.org/git/, http://marc.info/?l=git and other archival sites.

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