Move the logic for 'is_executable()' from help.c to run_command.c and
expose it so that callers from outside help.c can access the function.
This is to enable run-command to be able to query if a file is
executable in a future patch.
Signed-off-by: Brandon Williams <bmwill@google.com>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signal handlers of the parent firing in the forked child may
have unintended side effects. Rather than auditing every signal
handler we have and will ever have, block signals while forking
and restore default signal handlers in the child before execve.
Restoring default signal handlers is required because
execve does not unblock signals, it only restores default
signal handlers. So we must restore them with sigprocmask
before execve, leaving a window when signal handlers
we control can fire in the child. Continue ignoring
ignored signals, but reset the rest to defaults.
Similarly, disable pthread cancellation to future-proof our code
in case we start using cancellation; as cancellation is
implemented with signals in glibc.
Signed-off-by: Eric Wong <e@80x24.org>
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
All non-Async-Signal-Safe functions (e.g. malloc and die) were removed
between 'fork' and 'exec' in start_command in order to avoid potential
deadlocking when forking while multiple threads are running. This
deadlocking is possible when a thread (other than the one forking) has
acquired a lock and didn't get around to releasing it before the fork.
This leaves the lock in a locked state in the resulting process with no
hope of it ever being released.
Add a note describing this potential pitfall before the call to 'fork()'
so people working in this section of the code know to only use
Async-Signal-Safe functions in the child process.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
All of our standard error handling paths have the potential to
call malloc or take stdio locks; so we must avoid them inside
the forked child.
Instead, the child only writes an 8 byte struct atomically to
the parent through the notification pipe to propagate an error.
All user-visible error reporting happens from the parent;
even avoiding functions like atexit(3) and exit(3).
Helped-by: Eric Wong <e@80x24.org>
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In order to avoid allocation between 'fork()' and 'exec()' prepare the
environment to be used in the child process prior to forking.
Switch to using 'execve()' so that the construct child environment can
used in the exec'd process.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Teach string-list to be able to remove a string from a sorted
'struct string_list'.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert the function used to exec from 'execvp()' to 'execv()' as the (p)
variant of exec isn't async-signal-safe and has the potential to call malloc
during the path resolution it performs. Instead we simply do the path
resolution ourselves during the preparation stage prior to forking. There also
don't exist any portable (p) variants which also take in an environment to use
in the exec'd process. This allows easy migration to using 'execve()' in a
future patch.
Also, as noted in [1], in the event of an ENOEXEC the (p) variants of
exec will attempt to execute the command by interpreting it with the
'sh' utility. To maintain this functionality, if 'execv()' fails with
ENOEXEC, start_command will atempt to execute the command by
interpreting it with 'sh'.
[1] http://pubs.opengroup.org/onlinepubs/009695399/functions/exec.html
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
According to [1] we need to only call async-signal-safe operations between fork
and exec. Using malloc to build the argv array isn't async-signal-safe.
In order to avoid allocation between 'fork()' and 'exec()' prepare the
argv array used in the exec call prior to forking the process.
[1] http://pubs.opengroup.org/onlinepubs/009695399/functions/fork.html
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a test to 't0061-run-command.sh' to ensure that run_command can
continue to execute scripts which don't include a '#!' line.
As shell scripts are not natively executable on Windows, we use a
workaround to check "#!" when running scripts from Git. As this
test requires the platform (not with Git's help) to run scripts
without "#!", skipt it on Windows.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The post-update hooks created in t5550-http-fetch-dumb.sh is missing the
"!#/bin/sh" line which can cause issues with portability. Instead
create the hook using the 'write_script' function which includes the
proper "#!" line.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Update an error message.
* sb/unpack-trees-would-lose-submodule-message-update:
unpack-trees.c: align submodule error message to the other error messages
Update the build dependency so that an update to /usr/bin/perl
etc. result in recomputation of perl.mak file.
* ab/regen-perl-mak-with-different-perl:
perl: regenerate perl.mak if perl -V changes
"git diff --submodule=diff" learned to work better in a project
with a submodule that in turn has its own submodules.
* sb/show-diff-for-submodule-in-diff-fix:
diff: submodule inline diff to initialize env array.
Update error handling for codepath that deals with corrupt loose
objects.
* jk/loose-object-info-report-error:
index-pack: detect local corruption in collision check
sha1_loose_object_info: return error for corrupted objects
Code clean-up.
* jk/snprintf-cleanups:
daemon: use an argv_array to exec children
gc: replace local buffer with git_path
transport-helper: replace checked snprintf with xsnprintf
convert unchecked snprintf into xsnprintf
combine-diff: replace malloc/snprintf with xstrfmt
replace unchecked snprintf calls with heap buffers
receive-pack: print --pack-header directly into argv array
name-rev: replace static buffer with strbuf
create_branch: use xstrfmt for reflog message
create_branch: move msg setup closer to point of use
avoid using mksnpath for refs
avoid using fixed PATH_MAX buffers for refs
fetch: use heap buffer to format reflog
tag: use strbuf to format tag header
diff: avoid fixed-size buffer for patch-ids
odb_mkstemp: use git_path_buf
odb_mkstemp: write filename into strbuf
do not check odb_mkstemp return value for errors
The left and right base directories were pointed to the buf field of
two strbufs, which were subject to change.
A contrived test case shows the problem where a file with a long enough
name to force the strbuf to grow is up-to-date (hence the code path is
used where the work tree's version of the file is reused), and then a
file that is not up-to-date needs to be written (hence the code path is
used where checkout_entry() uses the previously recorded base_dir that
is invalid by now).
Let's just copy the base_dir strings for use with checkout_entry(),
never touch them until the end, and release them then. This is an easily
verifiable fix (as opposed to the next-obvious alternative: to re-set
base_dir after every loop iteration).
This fixes https://github.com/git-for-windows/git/issues/1124
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Define a new task in .travis.yml that triggers a test session on
Windows run elsewhere.
* ls/travis-relays-for-windows-ci:
travis-ci: build and test Git on Windows
The default behaviour of "git log" in an interactive session has
been changed to enable "--decorate".
* ah/log-decorate-default-to-auto:
log: if --decorate is not given, default to --decorate=auto
"git tag/branch/for-each-ref" family of commands long allowed to
filter the refs by "--contains X" (show only the refs that are
descendants of X), "--merged X" (show only the refs that are
ancestors of X), "--no-merged X" (show only the refs that are not
ancestors of X). One curious omission, "--no-contains X" (show
only the refs that are not descendants of X) has been added to
them.
* ab/ref-filter-no-contains:
tag: add tests for --with and --without
ref-filter: reflow recently changed branch/tag/for-each-ref docs
ref-filter: add --no-contains option to tag/branch/for-each-ref
tag: change --point-at to default to HEAD
tag: implicitly supply --list given another list-like option
tag: change misleading --list <pattern> documentation
parse-options: add OPT_NONEG to the "contains" option
tag: add more incompatibles mode tests
for-each-ref: partly change <object> to <commit> in help
tag tests: fix a typo in a test description
tag: remove a TODO item from the test suite
ref-filter: add test for --contains on a non-commit
ref-filter: make combining --merged & --no-merged an error
tag doc: reword --[no-]merged to talk about commits, not tips
tag doc: split up the --[no-]merged documentation
tag doc: move the description of --[no-]merged earlier
David reported:
> When I try to run `git diff --submodule=diff` in a submodule which has
> it's own submodules that have changes I get the error: fatal: bad
> object.
This happens, because we do not properly initialize the environment
in which the diff is run in the submodule. That means we inherit the
environment from the main process, which sets environment variables.
(Apparently we do set environment variables which we do not set
when not in a submodules, i.e. the .git directory is linked)
This commit, just like fd47ae6a5b (diff: teach diff to display
submodule difference with an inline diff, 2016-08-31) introduces bad
test code (i.e. hard coded hash values), which will be cleanup up in
a later patch.
Reported-by: David Parrish <daveparrish@gmail.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
List the fields in order of appearance in the command output.
Signed-off-by: Mostyn Bramley-Moore <mostyn@antipode.se>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When we notice that we have a local copy of an incoming
object, we compare the two objects to make sure we haven't
found a collision. Before we get to the actual object
bytes, though, we compare the type and size from
sha1_object_info().
If our local object is corrupted, then the type will be
OBJ_BAD, which obviously will not match the incoming type,
and we'll report "SHA1 COLLISION FOUND" (with capital
letters and everything). This is confusing, as the problem
is not a collision but rather local corruption. We should
report that instead (just like we do if reading the rest of
the object content fails a few lines later).
Note that we _could_ just ignore the error and mark it as a
non-collision. That would let you "git fetch" to replace a
corrupted object. But it's not a very reliable method for
repairing a repository. The earlier want/have negotiation
tries to get the other side to omit objects we already have,
and it would not realize that we are "missing" this
corrupted object. So we're better off complaining loudly
when we see corruption, and letting the user take more
drastic measures to repair (like making a full clone
elsewhere and copying the pack into place).
Note that the test sets transfer.unpackLimit in the
receiving repository so that we use index-pack (which is
what does the collision check). Normally for such a small
push we'd use unpack-objects, which would simply try to
write the loose object, and discard the new one when we see
that there's already an old one.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When sha1_loose_object_info() finds that a loose object file
cannot be stat(2)ed or mmap(2)ed, it returns -1 to signal an
error to the caller. However, if it found that the loose
object file is corrupt and the object data cannot be used
from it, it stuffs OBJ_BAD into "type" field of the
object_info, but returns zero (i.e., success), which can
confuse callers.
This is due to 052fe5eac (sha1_loose_object_info: make type
lookup optional, 2013-07-12), which switched the return to a
strict success/error, rather than returning the type (but
botched the return).
Callers of regular sha1_object_info() don't notice the
difference, as that function returns the type (which is
OBJ_BAD in this case). However, direct callers of
sha1_object_info_extended() see the function return success,
but without setting any meaningful values in the object_info
struct, leading them to access potentially uninitialized
memory.
The easiest way to see the bug is via "cat-file -s", which
will happily ignore the corruption and report whatever
value happened to be in the "size" variable.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Just like we did in 0d1d6e50 ("t/t7003: replace \t with literal tab
in sed expression", 2010-08-12), avoid writing "\t" for HT in sed
scripts, which is not portable.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since 068c77a5 ("builtin/send-pack.c: use parse_options API",
2015-08-19), there is no external user of this helper function.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Our struct child_process already has its own argv_array.
Let's use that to avoid having to format options into
separate buffers.
Note that we'll need to declare the child process outside of
the run_service_command() helper to do this. But that opens
up a further simplification, which is that the helper can
append to our argument list, saving each caller from
specifying "." manually.
Signed-off-by: Jeff King <peff@peff.net>
We probe the "17/" loose object directory for auto-gc, and
use a local buffer to format the path. We can just use
git_path() for this. It handles paths of any length
(reducing our error handling). And because we feed the
result straight to a system call, we can just use the static
variant.
Note that git_path also knows the string "objects/" is
special, and will replace it with git_object_directory()
when necessary.
Another alternative would be to use sha1_file_name() for the
pretend object "170000...", but that ends up being more
hassle for no gain, as we have to truncate the final path
component.
Signed-off-by: Jeff King <peff@peff.net>
We can use xsnprintf to do our truncation check with less
code. The error message isn't as specific, but the point is
that this isn't supposed to trigger in the first place
(because our buffer is big enough to handle any int).
Signed-off-by: Jeff King <peff@peff.net>
These calls to snprintf should always succeed, because their
input is small and fixed. Let's use xsnprintf to make sure
this is the case (and to make auditing for actual truncation
easier).
These could be candidates for turning into heap buffers, but
they fall into a few broad categories that make it not worth
doing:
- formatting single numbers is simple enough that we can
see the result should fit
- the size of a sha1 is likewise well-known, and I didn't
want to cause unnecessary conflicts with the ongoing
process to convert these constants to GIT_MAX_HEXSZ
- the interface for curl_errorstr is dictated by curl
Signed-off-by: Jeff King <peff@peff.net>
We'd prefer to avoid unchecked snprintf calls because
truncation can lead to unexpected results.
These are all cases where truncation shouldn't ever happen,
because the input to snprintf is fixed in size. That makes
them candidates for xsnprintf(), but it's simpler still to
just use the heap, and then nobody has to wonder if "100" is
big enough.
We'll use xstrfmt() where possible, and a strbuf when we need
the resulting size or to reuse the same buffer in a loop.
Signed-off-by: Jeff King <peff@peff.net>
After receive-pack reads the pack header from the client, it
feeds the already-read part to index-pack and unpack-objects
via their --pack-header command-line options. To do so, we
format it into a fixed buffer, then duplicate it into the
child's argv_array.
Our buffer is long enough to handle any possible input, so
this isn't wrong. But it's more complicated than it needs to
be; we can just argv_array_pushf() the final value and avoid
the intermediate copy. This drops the magic number and is
more efficient, too.
Note that we need to push to the argv_array in order, which
means we can't do the push until we are in the "unpack-objects
versus index-pack" conditional. Rather than duplicate the
slightly complicated format specifier, I pushed it into a
helper function.
Signed-off-by: Jeff King <peff@peff.net>
When name-rev needs to format an actual name, we do so into
a fixed-size buffer. That includes the actual ref tip, as
well as any traversal information. Since refs can exceed
1024 bytes, this means you can get a bogus result. E.g.,
doing:
git tag $(perl -e 'print join("/", 1..1024)')
git describe --contains HEAD^
results in ".../282/283", when it should be
".../1023/1024~1".
We can solve this by using a heap buffer. We'll use a
strbuf, which lets us write into the same buffer from our
loop without having to reallocate.
Signed-off-by: Jeff King <peff@peff.net>
We generate a reflog message that contains some fixed text
plus a branch name, and use a buffer of size PATH_MAX + 20.
This mostly works if you assume that refnames are shorter
than PATH_MAX, but:
1. That's not necessarily true. PATH_MAX is not always the
filesystem's limit.
2. The "20" is not sufficiently large for the fixed text
anyway.
Let's just switch to a heap buffer so we don't have to even
care.
Signed-off-by: Jeff King <peff@peff.net>
In create_branch() we write the reflog msg into a buffer in
the main function, but then use it only inside a
conditional. If you carefully follow the logic, you can
confirm that we never use the buffer uninitialized nor write
when it would not be used. But we can make this a lot more
obvious by simply moving the write step inside the
conditional.
Signed-off-by: Jeff King <peff@peff.net>
Like the previous commit, we'd like to avoid the assumption
that refs fit into PATH_MAX-sized buffers. These callsites
have an extra twist, though: they write the refnames using
mksnpath. This does two things beyond a regular snprintf:
1. It quietly writes "/bad-path/" when truncation occurs.
This saves the caller having to check the error code,
but if you aren't actually feeding the result to a
system call (and we aren't here), it's questionable.
2. It calls cleanup_path(), which removes leading
instances of "./". That's questionable when dealing
with refnames, as we could silently canonicalize a
syntactically bogus refname into a valid one.
Let's convert each case to use a strbuf. This is preferable
to xstrfmt() because we can reuse the same buffer as we
loop.
Signed-off-by: Jeff King <peff@peff.net>
Many functions which handle refs use a PATH_MAX-sized buffer
to do so. This is mostly reasonable as we have to write
loose refs into the filesystem, and at least on Linux the 4K
PATH_MAX is big enough that nobody would care. But:
1. The static PATH_MAX is not always the filesystem limit.
2. On other platforms, PATH_MAX may be much smaller.
3. As we move to alternate ref storage, we won't be bound
by filesystem limits.
Let's convert these to heap buffers so we don't have to
worry about truncation or size limits.
We may want to eventually constrain ref lengths for sanity
and to prevent malicious names, but we should do so
consistently across all platforms, and in a central place
(like the ref code).
Signed-off-by: Jeff King <peff@peff.net>
Part of the reflog content comes from the environment, which
can be much larger than our fixed buffer. Let's use a heap
buffer so we avoid truncating it.
Signed-off-by: Jeff King <peff@peff.net>
We format the tag header into a fixed 1024-byte buffer. But
since the tag-name and tagger ident can be arbitrarily
large, we may unceremoniously die with "tag header too big".
Let's just use a strbuf instead.
Note that it looks at first glance like we can just format
this directly into the "buf" strbuf where it will ultimately
go. But that buffer may already contain the tag message, and
we have no easy way to prepend formatted data to a strbuf
(we can only splice in an already-generated buffer). This
isn't a performance-critical path, so going through an extra
buffer isn't a big deal.
Signed-off-by: Jeff King <peff@peff.net>
