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302 Commits

Author SHA1 Message Date
Aaron Schrab 5a7da2dca1 hooks: Add function to check if a hook exists
Create find_hook() function to determine if a given hook exists and is
executable.  If it is, the path to the script will be returned,
otherwise NULL is returned.

This encapsulates the tests that are used to check for the existence of
a hook in one place, making it easier to modify those checks if that is
found to be necessary.  This also makes it simple for places that can
use a hook to check if a hook exists before doing, possibly lengthy,
setup work which would be pointless if no such hook is present.

The returned value is left as a static value from get_pathname() rather
than a duplicate because it is anticipated that the return value will
either be used as a boolean, immediately added to an argv_array list
which would result in it being duplicated at that point, or used to
actually run the command without much intervening work.  Callers which
need to hold onto the returned value for a longer time are expected to
duplicate the return value themselves.

Signed-off-by: Aaron Schrab <aaron@schrab.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-01-14 09:25:40 -08:00
Jeff King 709ca730f8 run-command: encode signal death as a positive integer
When a sub-command dies due to a signal, we encode the
signal number into the numeric exit status as "signal -
128". This is easy to identify (versus a regular positive
error code), and when cast to an unsigned integer (e.g., by
feeding it to exit), matches what a POSIX shell would return
when reporting a signal death in $? or through its own exit
code.

So we have a negative value inside the code, but once it
passes across an exit() barrier, it looks positive (and any
code we receive from a sub-shell will have the positive
form). E.g., death by SIGPIPE (signal 13) will look like
-115 to us in inside git, but will end up as 141 when we
call exit() with it. And a program killed by SIGPIPE but run
via the shell will come to us with an exit code of 141.

Unfortunately, this means that when the "use_shell" option
is set, we need to be on the lookout for _both_ forms. We
might or might not have actually invoked the shell (because
we optimize out some useless shell calls). If we didn't invoke
the shell, we will will see the sub-process's signal death
directly, and run-command converts it into a negative value.
But if we did invoke the shell, we will see the shell's
128+signal exit status. To be thorough, we would need to
check both, or cast the value to an unsigned char (after
checking that it is not -1, which is a magic error value).

Fortunately, most callsites do not care at all whether the
exit was from a code or from a signal; they merely check for
a non-zero status, and sometimes propagate the error via
exit(). But for the callers that do care, we can make life
slightly easier by just using the consistent positive form.

This actually fixes two minor bugs:

  1. In launch_editor, we check whether the editor died from
     SIGINT or SIGQUIT. But we checked only the negative
     form, meaning that we would fail to notice a signal
     death exit code which was propagated through the shell.

  2. In handle_alias, we assume that a negative return value
     from run_command means that errno tells us something
     interesting (like a fork failure, or ENOENT).
     Otherwise, we simply propagate the exit code. Negative
     signal death codes confuse us, and we print a useless
     "unable to run alias 'foo': Success" message. By
     encoding signal deaths using the positive form, the
     existing code just propagates it as it would a normal
     non-zero exit code.

The downside is that callers of run_command can no longer
differentiate between a signal received directly by the
sub-process, and one propagated. However, no caller
currently cares, and since we already optimize out some
calls to the shell under the hood, that distinction is not
something that should be relied upon by callers.

Fix the same logic in t/test-terminal.perl for consistency [jc:
raised by Jonathan in the discussion].

Signed-off-by: Jeff King <peff@peff.net>
Acked-by: Johannes Sixt <j6t@kdbg.org>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-01-06 11:09:18 -08:00
Jeff King 0398fc3496 fix compilation with NO_PTHREADS
Commit 1327452 cleaned up an unused parameter from
wait_or_whine, but forgot to update a caller that is inside
"#ifdef NO_PTHREADS".

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-01-05 22:47:27 -08:00
Jeff King a2767c5c91 run-command: do not warn about child death from terminal
SIGINT and SIGQUIT are not generally interesting signals to
the user, since they are typically caused by them hitting "^C"
or otherwise telling their terminal to send the signal.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-12-02 02:06:43 -08:00
Jeff King 13274526c1 run-command: drop silent_exec_failure arg from wait_or_whine
We do not actually use this parameter; instead we complain
from the child itself (for fork/exec) or from start_command
(if we are using spawn on Windows).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-12-02 02:04:50 -08:00
Jeff King 55ff630075 Merge branch 'jk/no-more-pre-exec-callback'
Removes a workaround for buggy version of less older than version
406.

* jk/no-more-pre-exec-callback:
  pager: drop "wait for output to run less" hack
2012-10-25 06:41:15 -04:00
Junio C Hamano cc84144d48 Merge branch 'dg/run-command-child-cleanup' into maint
* dg/run-command-child-cleanup:
  run-command.c: fix broken list iteration in clear_child_for_cleanup
2012-09-20 15:55:12 -07:00
Junio C Hamano 5816cc7ca1 Merge branch 'dg/run-command-child-cleanup'
The code to wait for subprocess and remove it from our internal queue
wasn't quite right.

* dg/run-command-child-cleanup:
  run-command.c: fix broken list iteration in clear_child_for_cleanup
2012-09-14 21:39:37 -07:00
Junio C Hamano 91feb387f2 Merge branch 'jc/maint-sane-execvp-notdir' into maint-1.7.11
* jc/maint-sane-execvp-notdir:
  sane_execvp(): ignore non-directory on $PATH
2012-09-11 11:09:19 -07:00
David Gould bdee397d7c run-command.c: fix broken list iteration in clear_child_for_cleanup
Iterate through children_to_clean using 'next' fields but with an
extra level of indirection. This allows us to update the chain when
we remove a child and saves us managing several variables around
the loop mechanism.

Signed-off-by: David Gould <david@optimisefitness.com>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-09-11 10:30:31 -07:00
Junio C Hamano 12d858aeb4 Merge branch 'jc/maint-sane-execvp-notdir'
"git foo" errored out with "Not a directory" when the user had a non
directory on $PATH, and worse yet it masked an alias "foo" to run.

* jc/maint-sane-execvp-notdir:
  sane_execvp(): ignore non-directory on $PATH
2012-09-03 15:53:26 -07:00
Junio C Hamano a78550831a sane_execvp(): ignore non-directory on $PATH
When you have a non-directory on your PATH, a funny thing happens:

	$ PATH=$PATH:/bin/sh git foo
	fatal: cannot exec 'git-foo': Not a directory?

Worse yet, as real commands always take precedence over aliases,
this behaviour interacts rather badly with them:

	$ PATH=$PATH:/bin/sh git -c alias.foo=show git foo -s
	fatal: cannot exec 'git-foo': Not a directory?

This is because an ENOTDIR error from the underlying execvp(2) is
reported back to the caller of our sane_execvp() wrapper as-is.

Translating it to ENOENT, just like the case where we _might_ have
the command in an unreadable directory, fixes it.  Without an alias,
we would get

	git: 'foo' is not a git command. See 'git --help'.

and we use the 'foo' alias when it is available, of course.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-07-31 12:51:30 -07:00
Jeff King e8320f350f pager: drop "wait for output to run less" hack
Commit 35ce862 (pager: Work around window resizing bug in
'less', 2007-01-24) causes git's pager sub-process to wait
to receive input after forking but before exec-ing the
pager. To handle this, run-command had to grow a "pre-exec
callback" feature. Unfortunately, this feature does not work
at all on Windows (where we do not fork), and interacts
poorly with run-command's parent notification system. Its
use should be discouraged.

The bug in less was fixed in version 406, which was released
in June 2007. It is probably safe at this point to remove
our workaround. That lets us rip out the preexec_cb feature
entirely.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-06-05 09:38:00 -07:00
Junio C Hamano 8cc5223495 Merge branch 'js/spawn-via-shell-path-fix'
Mops up an unfortunate fallout from bw/spawn-via-shell-path topic.

By Johannes Sixt
* js/spawn-via-shell-path-fix:
  Do not use SHELL_PATH from build system in prepare_shell_cmd on Windows
2012-04-20 15:51:18 -07:00
Junio C Hamano bd6f71d1fc Merge branch 'jk/run-command-eacces'
When PATH contains an unreadable directory, alias expansion code did not
kick in, and failed with an error that said "git-subcmd" was not found.

By Jeff King (1) and Ramsay Jones (1)
* jk/run-command-eacces:
  run-command: treat inaccessible directories as ENOENT
  compat/mingw.[ch]: Change return type of exec functions to int
2012-04-20 15:50:03 -07:00
Johannes Sixt 776297548e Do not use SHELL_PATH from build system in prepare_shell_cmd on Windows
The recent change to use SHELL_PATH instead of "sh" to spawn shell commands
is not suited for Windows:

- The default setting, "/bin/sh", does not work when git has to run the
  shell because it is a POSIX style path, but not a proper Windows style
  path.

- If it worked, it would hard-code a position in the files system where
  the shell is expected, making git (more precisely, the POSIX toolset that
  is needed alongside git) non-relocatable. But we cannot sacrifice
  relocatability on Windows.

- Apart from that, even though the Makefile leaves SHELL_PATH set to
  "/bin/sh" for the Windows builds, the build system passes a mangled path
  to the compiler, and something like "D:/Src/msysgit/bin/sh" is used,
  which is doubly bad because it points to where /bin/sh resolves to on
  the system where git was built.

- Finally, the system's CreateProcess() function that is used under
  mingw.c's hood does not work with forward slashes and cannot find the
  shell.

Undo the earlier change on Windows.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-04-17 08:51:54 -07:00
Jeff King 38f865c27d run-command: treat inaccessible directories as ENOENT
When execvp reports EACCES, it can be one of two things:

  1. We found a file to execute, but did not have
     permissions to do so.

  2. We did not have permissions to look in some directory
     in the $PATH.

In the former case, we want to consider this a
permissions problem and report it to the user as such (since
getting this for something like "git foo" is likely a
configuration error).

In the latter case, there is a good chance that the
inaccessible directory does not contain anything of
interest. Reporting "permission denied" is confusing to the
user (and prevents our usual "did you mean...?" lookup). It
also prevents git from trying alias lookup, since we do so
only when an external command does not exist (not when it
exists but has an error).

This patch detects EACCES from execvp, checks whether we are
in case (2), and if so converts errno to ENOENT. This
behavior matches that of "bash" (but not of simpler shells
that use execvp more directly, like "dash").

Test stolen from Junio.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-04-05 16:24:13 -07:00
Ben Walton b3e34dddc0 Use SHELL_PATH from build system in run_command.c:prepare_shell_cmd
During the testing of the 1.7.10 rc series on Solaris for OpenCSW, it
was discovered that t7006-pager was failing due to finding a bad "sh"
in PATH after a call to execvp("sh", ...).  This call was setup by
run_command.c:prepare_shell_cmd.

The PATH in use at the time saw /opt/csw/bin given precedence to
traditional Solaris paths such as /usr/bin and /usr/xpg4/bin.  A
package named schilyutils (Joerg Schilling's utilities) was installed
on the build system and it delivered a modified version of the
traditional Solaris /usr/bin/sh as /opt/csw/bin/sh.  This version of
sh suffers from many of the same problems as /usr/bin/sh.

The command-specific pager test failed due to the broken "sh" handling
^ as a pipe character.  It tried to fork two processes when it
encountered "sed s/^/foo:/" as the pager command.  This problem was
entirely dependent on the PATH of the user at runtime.

Possible fixes for this issue are:

1. Use the standard system() or popen() which both launch a POSIX
   shell on Solaris as long as _POSIX_SOURCE is defined.

2. The git wrapper could prepend SANE_TOOL_PATH to PATH thus forcing
   all unqualified commands run to use the known good tools on the
   system.

3. The run_command.c:prepare_shell_command() could use the same
   SHELL_PATH that is in the #! line of all all scripts and not rely
   on PATH to find the sh to run.

Option 1 would preclude opening a bidirectional pipe to a filter
script and would also break git for Windows as cmd.exe is spawned from
system() (cf. v1.7.5-rc0~144^2, "alias: use run_command api to execute
aliases, 2011-01-07).

Option 2 is not friendly to users as it would negate their ability to
use tools of their choice in many cases.  Alternately, injecting
SANE_TOOL_PATH such that it takes precedence over /bin and /usr/bin
(and anything with lower precedence than those paths) as
git-sh-setup.sh does would not solve the problem either as the user
environment could still allow a bad sh to be found.  (Many OpenCSW
users will have /opt/csw/bin leading their PATH and some subset would
have schilyutils installed.)

Option 3 allows us to use a known good shell while still honouring the
users' PATH for the utilities being run.  Thus, it solves the problem
while not negatively impacting either users or git's ability to run
external commands in convenient ways.  Essentially, the shell is a
special case of tool that should not rely on SANE_TOOL_PATH and must
be called explicitly.

With this patch applied, any code path leading to
run_command.c:prepare_shell_cmd can count on using the same sane shell
that all shell scripts in the git suite use.  Both the build system
and run_command.c will default this shell to /bin/sh unless
overridden.

Signed-off-by: Ben Walton <bwalton@artsci.utoronto.ca>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-04-03 17:24:20 -07:00
Clemens Buchacher 10c6cddd92 dashed externals: kill children on exit
Several git commands are so-called dashed externals, that is commands
executed as a child process of the git wrapper command. If the git
wrapper is killed by a signal, the child process will continue to run.
This is different from internal commands, which always die with the git
wrapper command.

Enable the recently introduced cleanup mechanism for child processes in
order to make dashed externals act more in line with internal commands.

Signed-off-by: Clemens Buchacher <drizzd@aon.at>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-01-08 15:07:20 -08:00
Jeff King afe19ff7b5 run-command: optionally kill children on exit
When we spawn a helper process, it should generally be done
and finish_command called before we exit. However, if we
exit abnormally due to an early return or a signal, the
helper may continue to run in our absence.

In the best case, this may simply be wasted CPU cycles or a
few stray messages on a terminal. But it could also mean a
process that the user thought was aborted continues to run
to completion (e.g., a push's pack-objects helper will
complete the push, even though you killed the push process).

This patch provides infrastructure for run-command to keep
track of PIDs to be killed, and clean them on signal
reception or input, just as we do with tempfiles. PIDs can
be added in two ways:

  1. If NO_PTHREADS is defined, async helper processes are
     automatically marked. By definition this code must be
     ready to die when the parent dies, since it may be
     implemented as a thread of the parent process.

  2. If the run-command caller specifies the "clean_on_exit"
     option. This is not the default, as there are cases
     where it is OK for the child to outlive us (e.g., when
     spawning a pager).

PIDs are cleared from the kill-list automatically during
wait_or_whine, which is called from finish_command and
finish_async.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Clemens Buchacher <drizzd@aon.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-01-08 15:06:35 -08:00
Junio C Hamano 7a95d1be03 Merge branch 'jk/argv-array'
* jk/argv-array:
  run_hook: use argv_array API
  checkout: use argv_array API
  bisect: use argv_array API
  quote: provide sq_dequote_to_argv_array
  refactor argv_array into generic code
  quote.h: fix bogus comment
  add sha1_array API docs
2011-10-05 12:36:24 -07:00
Jeff King 5d40a17985 run_hook: use argv_array API
This was a pretty straightforward use, so it really doesn't
save that many lines. Still, perhaps it's a little bit more
readable.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-09-14 11:57:33 -07:00
Clemens Buchacher fc1b56f054 notice error exit from pager
If the pager fails to run, git produces no output, e.g.:

 $ GIT_PAGER=not-a-command git log

The error reporting fails for two reasons:

 (1) start_command: There is a mechanism that detects errors during
     execvp introduced in 2b541bf8 (start_command: detect execvp
     failures early). The child writes one byte to a pipe only if
     execvp fails.  The parent waits for either EOF, when the
     successful execvp automatically closes the pipe (see
     FD_CLOEXEC in fcntl(1)), or it reads a single byte, in which
     case it knows that the execvp failed. This mechanism is
     incompatible with the workaround introduced in 35ce8622
     (pager: Work around window resizing bug in 'less'), which
     waits for input from the parent before the exec. Since both
     the parent and the child are waiting for input from each
     other, that would result in a deadlock. In order to avoid
     that, the mechanism is disabled by closing the child_notifier
     file descriptor.

 (2) finish_command: The parent correctly detects the 127 exit
     status from the child, but the error output goes nowhere,
     since by that time it is already being redirected to the
     child.

No simple solution for (1) comes to mind.

Number (2) can be solved by not sending error output to the pager.
Not redirecting error output to the pager can result in the pager
overwriting error output with standard output, however.

Since there is no reliable way to handle error reporting in the
parent, produce the output in the child instead.

Signed-off-by: Clemens Buchacher <drizzd@aon.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-01 16:21:55 -07:00
Clemens Buchacher 3bc4181fde error_routine: use parent's stderr if exec fails
The new process's error output may be redirected elsewhere, but if
the exec fails, output should still go to the parent's stderr. This
has already been done for the die_routine. Do the same for
error_routine.

Signed-off-by: Clemens Buchacher <drizzd@aon.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-07-31 18:27:07 -07:00
Jonathan Nieder a111eb7808 run-command: handle short writes and EINTR in die_child
If start_command fails after forking and before exec finishes, there
is not much use in noticing an I/O error on top of that.
finish_command will notice that the child exited with nonzero status
anyway.  So as noted in v1.7.0.3~20^2 (run-command.c: fix build
warnings on Ubuntu, 2010-01-30) and v1.7.5-rc0~29^2 (2011-03-16), it
is safe to ignore errors from write in this codepath.

Even so, the result from write contains useful information: it tells
us if the write was cancelled by a signal (EINTR) or was only
partially completed (e.g., when writing to an almost-full pipe).
Let's use write_in_full to loop until the desired number of bytes have
been written (still ignoring errors if that fails).

As a happy side effect, the assignment to a dummy variable to appease
gcc -D_FORTIFY_SOURCE is no longer needed.  xwrite and write_in_full
check the return value from write(2).

Noticed with gcc -Wunused-but-set-variable.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-04-20 10:09:26 -07:00
Junio C Hamano 60e199c4d5 Revert "run-command: prettify -D_FORTIFY_SOURCE workaround"
This reverts commit ebec842773, which
somehow mistakenly thought that any non-zero return from write(2) is
an error.
2011-04-18 14:14:53 -07:00
Jonathan Nieder ebec842773 run-command: prettify -D_FORTIFY_SOURCE workaround
Current gcc + glibc with -D_FORTIFY_SOURCE try very aggressively to
protect against a programming style which uses write(...) without
checking the return value for errors.  Even the usual hint of casting
to (void) does not suppress the warning.

Sometimes when there is an output error, especially right before exit,
there really is nothing to be done.  The obvious solution, adopted in
v1.7.0.3~20^2 (run-command.c: fix build warnings on Ubuntu,
2010-01-30), is to save the return value to a dummy variable:

	ssize_t dummy;
	dummy = write(...);

But that (1) is ugly and (2) triggers -Wunused-but-set-variable
warnings with gcc-4.6 -Wall, so we are not much better off than when
we started.

Instead, use an "if" statement with an empty body to make the intent
clear.

	if (write(...))
		; /* yes, yes, there was an error. */

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Improved-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-03-17 15:32:43 -07:00
Johannes Sixt 13af8cbd6a start_command: flush buffers in the WIN32 code path as well
The POSIX code path did The Right Thing already, but we have to do the same
on Windows.

This bug caused failures in t5526-fetch-submodules, where the output of
'git fetch --recurse-submodules' was in the wrong order.

Debugged-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-02-07 14:18:56 -08:00
Junio C Hamano 762655010d Merge branch 'js/async-thread'
* js/async-thread:
  fast-import: die_nicely() back to vsnprintf (reverts part of ebaa79f)
  Enable threaded async procedures whenever pthreads is available
  Dying in an async procedure should only exit the thread, not the process.
  Reimplement async procedures using pthreads
  Windows: more pthreads functions
  Fix signature of fcntl() compatibility dummy
  Make report() from usage.c public as vreportf() and use it.
  Modernize t5530-upload-pack-error.

Conflicts:
	http-backend.c
2010-06-21 06:02:45 -07:00
bert Dvornik fc012c2810 start_command: close cmd->err descriptor when fork/spawn fails
Fix the problem where the cmd->err passed into start_command wasn't
being properly closed when certain types of errors occurr.  (Compare
the affected code with the clean shutdown code later in the function.)

On Windows, this problem would be triggered if mingw_spawnvpe()
failed, which would happen if the command to be executed was malformed
(e.g. a text file that didn't start with a #! line).  If cmd->err was
a pipe, the failure to close it could result in a hang while the other
side was waiting (forever) for either input or pipe close, e.g. while
trying to shove the output into the side band.  On msysGit, this
problem was causing a hang in t5516-fetch-push.

[J6t: With a slight adjustment of the test case, the hang is also
observed on Linux.]

Signed-off-by: bert Dvornik <dvornik+git@gmail.com>
Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-05-20 16:11:29 -07:00
Junio C Hamano 4553d58f37 Merge branch 'jl/maint-submodule-gitfile-awareness'
* jl/maint-submodule-gitfile-awareness:
  Windows: start_command: Support non-NULL dir in struct child_process
2010-04-11 13:54:28 -07:00
Johannes Sixt f9a2743c35 Windows: start_command: Support non-NULL dir in struct child_process
A caller of start_command can set the member 'dir' to a directory to
request that the child process starts with that directory as CWD. The first
user of this feature was added recently in eee49b6 (Teach diff --submodule
and status to handle .git files in submodules).

On Windows, we have been lazy and had not implemented support for this
feature, yet. This fixes the shortcoming.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-04-11 13:48:46 -07:00
Johannes Sixt f6b6098316 Enable threaded async procedures whenever pthreads is available
Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-03-10 14:26:54 -08:00
Junio C Hamano b7e7f6fb00 Merge branch 'mw/maint-gcc-warns-unused-write'
* mw/maint-gcc-warns-unused-write:
  run-command.c: fix build warnings on Ubuntu
2010-03-07 12:47:18 -08:00
Johannes Sixt 0ea1c89ba6 Dying in an async procedure should only exit the thread, not the process.
Async procedures are intended as helpers that perform a very restricted
task, and the caller usually has to manage them in a larger context.
Conceptually, the async procedure is not concerned with the "bigger
picture" in whose context it is run. When it dies, it is not supposed
to destroy this "bigger picture", but rather only its own limit view
of the world. On POSIX, the async procedure is run in its own process,
and exiting this process naturally had only these limited effects.

On Windows (or when ASYNC_AS_THREAD is set), calling die() exited the
whole process, destroying the caller (the "big picture") as well.
This fixes it to exit only the thread.

Without ASYNC_AS_THREAD, one particular effect of exiting the async
procedure process is that it automatically closes file descriptors, most
notably the writable end of the pipe that the async procedure writes to.

The async API already requires that the async procedure closes the pipe
ends when it exits normally. But for calls to die() no requirements are
imposed. In the non-threaded case the pipe ends are closed implicitly
by the exiting process, but in the threaded case, the die routine must
take care of closing them.

Now t5530-upload-pack-error.sh passes on Windows.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-03-07 00:37:36 -08:00
Johannes Sixt 200a76b74d Reimplement async procedures using pthreads
On Windows, async procedures have always been run in threads, and the
implementation used Windows specific APIs. Rewrite the code to use pthreads.

A new configuration option is introduced so that the threaded implementation
can also be used on POSIX systems. Since this option is intended only as
playground on POSIX, but is mandatory on Windows, the option is not
documented.

One detail is that on POSIX it is necessary to set FD_CLOEXEC on the pipe
handles. On Windows, this is not needed because pipe handles are not
inherited to child processes, and the new calls to set_cloexec() are
effectively no-ops.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-03-07 00:37:36 -08:00
Michael Wookey 90ff12a860 run-command.c: fix build warnings on Ubuntu
Building git on Ubuntu 9.10 warns that the return value of write(2)
isn't checked. These warnings were introduced in commits:

  2b541bf8 ("start_command: detect execvp failures early")
  a5487ddf ("start_command: report child process setup errors to the
parent's stderr")

GCC details:

  $ gcc --version
  gcc (Ubuntu 4.4.1-4ubuntu9) 4.4.1

Silence the warnings by reading (but not making use of) the return value
of write(2).

Signed-off-by: Michael Wookey <michaelwookey@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-03-03 22:47:24 -08:00
Junio C Hamano 76d44c8cfd Merge branch 'sp/maint-push-sideband' into sp/push-sideband
* sp/maint-push-sideband:
  receive-pack: Send hook output over side band #2
  receive-pack: Wrap status reports inside side-band-64k
  receive-pack: Refactor how capabilities are shown to the client
  send-pack: demultiplex a sideband stream with status data
  run-command: support custom fd-set in async
  run-command: Allow stderr to be a caller supplied pipe
  Update git fsck --full short description to mention packs

Conflicts:
	run-command.c
2010-02-05 21:08:53 -08:00
Erik Faye-Lund ae6a5609c0 run-command: support custom fd-set in async
This patch adds the possibility to supply a set of non-0 file
descriptors for async process communication instead of the
default-created pipe.

Additionally, we now support bi-directional communiction with the
async procedure, by giving the async function both read and write
file descriptors.

To retain compatiblity and similar "API feel" with start_command,
we require start_async callers to set .out = -1 to get a readable
file descriptor.  If either of .in or .out is 0, we supply no file
descriptor to the async process.

[sp: Note: Erik started this patch, and a huge bulk of it is
     his work.  All bugs were introduced later by Shawn.]

Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-02-05 20:57:22 -08:00
Shawn O. Pearce 4f41b61148 run-command: Allow stderr to be a caller supplied pipe
Like .out, .err may now be set to a file descriptor > 0, which
is a writable pipe/socket/file that the child's stderr will be
redirected into.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-02-05 20:57:16 -08:00
Junio C Hamano 030b1a77f7 Merge branch 'js/exec-error-report'
* js/exec-error-report:
  Improve error message when a transport helper was not found
  start_command: detect execvp failures early
  run-command: move wait_or_whine earlier
  start_command: report child process setup errors to the parent's stderr

Conflicts:
	Makefile
2010-01-20 14:44:12 -08:00
Junio C Hamano 3cd02df46a Merge branch 'js/windows'
* js/windows:
  Do not use date.c:tm_to_time_t() from compat/mingw.c
  MSVC: Windows-native implementation for subset of Pthreads API
  MSVC: Fix an "incompatible pointer types" compiler warning
  Windows: avoid the "dup dance" when spawning a child process
  Windows: simplify the pipe(2) implementation
  Windows: boost startup by avoiding a static dependency on shell32.dll
  Windows: disable Python
2010-01-18 18:12:49 -08:00
Johannes Sixt 75301f9015 Windows: avoid the "dup dance" when spawning a child process
When stdin, stdout, or stderr must be redirected for a child process that
on Windows is spawned using one of the spawn() functions of Microsoft's
C runtime, then there is no choice other than to

1. make a backup copy of fd 0,1,2 with dup
2. dup2 the redirection source fd into 0,1,2
3. spawn
4. dup2 the backup back into 0,1,2
5. close the backup copy and the redirection source

We used this idiom as well -- but we are not using the spawn() functions
anymore!

Instead, we have our own implementation. We had hardcoded that stdin,
stdout, and stderr of the child process were inherited from the parent's
fds 0, 1, and 2. But we can actually specify any fd.

With this patch, the fds to inherit are passed from start_command()'s
WIN32 section to our spawn implementation. This way, we can avoid the
backup copies of the fds.

The backup copies were a bug waiting to surface: The OS handles underlying
the dup()ed fds were inherited by the child process (but were not
associated with a file descriptor in the child). Consequently, the file or
pipe represented by the OS handle remained open even after the backup copy
was closed in the parent process until the child exited.

Since our implementation of pipe() creates non-inheritable OS handles, we
still dup() file descriptors in start_command() because dup() happens to
create inheritable duplicates. (A nice side effect is that the fd cleanup
in start_command is the same for Windows and Unix and remains unchanged.)

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-01-16 16:43:53 -08:00
Johannes Sixt 2b541bf8be start_command: detect execvp failures early
Previously, failures during execvp could be detected only by
finish_command. However, in some situations it is beneficial for the
parent process to know earlier that the child process will not run.

The idea to use a pipe to signal failures to the parent process and
the test case were lifted from patches by Ilari Liusvaara.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-01-10 10:15:03 -08:00
Johannes Sixt ab0b41daf6 run-command: move wait_or_whine earlier
We want to reuse it from start_command.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-01-10 10:05:52 -08:00
Johannes Sixt a5487ddf0f start_command: report child process setup errors to the parent's stderr
When the child process's environment is set up in start_command(), error
messages were written to wherever the parent redirected the child's stderr
channel. However, even if the parent redirected the child's stderr, errors
during this setup process, including the exec itself, are usually an
indication of a problem in the parent's environment. Therefore, the error
messages should go to the parent's stderr.

Redirection of the child's error messages is usually only used to redirect
hook error messages during client-server exchanges. In these cases, hook
setup errors could be regarded as information leak.

This patch makes a copy of stderr if necessary and uses a special
die routine that is used for all die() calls in the child that sends the
errors messages to the parent's stderr.

The trace call that reported a failed execvp is removed (because it writes
to stderr) and replaced by die_errno() with special treatment of ENOENT.
The improvement in the error message can be seen with this sequence:

   mkdir .git/hooks/pre-commit
   git commit

Previously, the error message was

   error: cannot run .git/hooks/pre-commit: No such file or directory

and now it is

   fatal: cannot exec '.git/hooks/pre-commit': Permission denied

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-01-10 10:05:34 -08:00
Jeff King f445644fd2 run-command: optimize out useless shell calls
If there are no metacharacters in the program to be run, we
can just skip running the shell entirely and directly exec
the program.

The metacharacter test is pulled verbatim from
launch_editor, which already implements this optimization.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-01-05 23:41:50 -08:00
Jeff King 8dba1e634a run-command: add "use shell" option
Many callsites run "sh -c $CMD" to run $CMD. We can make it
a little simpler for them by factoring out the munging of
argv.

For simple cases with no arguments, this doesn't help much, but:

  1. For cases with arguments, we save the caller from
     having to build the appropriate shell snippet.

  2. We can later optimize to avoid the shell when
     there are no metacharacters in the program.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-01-01 17:53:46 -08:00
Frank Li 71064e3f86 Test for WIN32 instead of __MINGW32_
The code which is conditional on MinGW32 is actually conditional on Windows.
Use the WIN32 symbol, which is defined by the MINGW32 and MSVC environments,
but not by Cygwin.

Define SNPRINTF_SIZE_CORR=1 for MSVC too, as its vsnprintf function does
not add NUL at the end of the buffer if the result fits the buffer size
exactly.

Signed-off-by: Frank Li <lznuaa@gmail.com>
Signed-off-by: Marius Storm-Olsen <mstormo@gmail.com>
Acked-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-09-18 20:00:42 -07:00
Frank Li d7fa500fb5 Fix __stdcall placement and function prototype
MSVC requires __stdcall to be between the functions return value and the
function name, and that the function pointer type is in the form of

    return_type (WINAPI *function_name)(arguments...)

Signed-off-by: Frank Li <lznuaa@gmail.com>
Signed-off-by: Marius Storm-Olsen <mstormo@gmail.com>
Acked-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-09-18 20:00:42 -07:00
Frank Li 0d30ad71fa Avoid declaration after statement
MSVC does not understand this C99 style.

Signed-off-by: Frank Li <lznuaa@gmail.com>
Signed-off-by: Marius Storm-Olsen <mstormo@gmail.com>
Acked-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-09-18 20:00:41 -07:00
Johannes Sixt 2affea4125 start_command: do not clobber cmd->env on Windows code path
Previously, it would not be possible to call start_command twice for the
same struct child_process that has env set.

The fix is achieved by moving the loop that modifies the environment block
into a helper function. This also allows us to make two other helper
functions static.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-09-11 16:33:54 -07:00
Junio C Hamano 08ac69685a Merge branch 'js/run-command-updates'
* js/run-command-updates:
  api-run-command.txt: describe error behavior of run_command functions
  run-command.c: squelch a "use before assignment" warning
  receive-pack: remove unnecessary run_status report
  run_command: report failure to execute the program, but optionally don't
  run_command: encode deadly signal number in the return value
  run_command: report system call errors instead of returning error codes
  run_command: return exit code as positive value
  MinGW: simplify waitpid() emulation macros
2009-08-10 22:14:57 -07:00
David Soria Parra 5a7a3671b7 run-command.c: squelch a "use before assignment" warning
i686-apple-darwin9-gcc-4.0.1 (GCC) 4.0.1 (Apple Inc. build 5490) compiler
(and probably others) mistakenly thinks variable failed_errno is used
before assigned.  Work it around by giving it a fake initialization.

Signed-off-by: David Soria Parra <dsp@php.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-08-04 10:04:29 -07:00
Johannes Sixt c024beb56d run_command: report failure to execute the program, but optionally don't
In the case where a program was not found, it was still the task of the
caller to report an error to the user. Usually, this is an interesting case
but only few callers actually reported a specific error (though many call
sites report a generic error message regardless of the cause).

With this change the error is reported by run_command, but since there is
one call site in git.c that does not want that, an option is added to
struct child_process, which is used to turn the error off.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-07-06 02:45:50 -07:00
Johannes Sixt b99d5f40d6 run_command: encode deadly signal number in the return value
We now write the signal number in the error message if the program
terminated by a signal. The negative return value is constructed such that
after truncation to 8 bits it looks like a POSIX shell's $?:

   $ echo 0000 | { git upload-pack .; echo $? >&2; } | :
   error: git-upload-pack died of signal 13
   141

Previously, the exit code was 255 instead of 141.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-07-06 02:44:56 -07:00
Johannes Sixt 0ac77ec315 run_command: report system call errors instead of returning error codes
The motivation for this change is that system call failures are serious
errors that should be reported to the user, but only few callers took the
burden to decode the error codes that the functions returned into error
messages.

If at all, then only an unspecific error message was given. A prominent
example is this:

   $ git upload-pack . | :
   fatal: unable to run 'git-upload-pack'

In this example, git-upload-pack, the external command invoked through the
git wrapper, dies due to SIGPIPE, but the git wrapper does not bother to
report the real cause. In fact, this very error message is copied to the
syslog if git-daemon's client aborts the connection early.

With this change, system call failures are reported immediately after the
failure and only a generic failure code is returned to the caller. In the
above example the error is now to the point:

   $ git upload-pack . | :
   error: git-upload-pack died of signal

Note that there is no error report if the invoked program terminated with
a non-zero exit code, because it is reasonable to expect that the invoked
program has already reported an error. (But many run_command call sites
nevertheless write a generic error message.)

There was one special return code that was used to identify the case where
run_command failed because the requested program could not be exec'd. This
special case is now treated like a system call failure with errno set to
ENOENT. No error is reported in this case, because the call site in git.c
expects this as a normal result. Therefore, the callers that carefully
decoded the return value still check for this condition.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-07-06 02:44:49 -07:00
Johannes Sixt 5709e0363a run_command: return exit code as positive value
As a general guideline, functions in git's code return zero to indicate
success and negative values to indicate failure. The run_command family of
functions followed this guideline. But there are actually two different
kinds of failure:

- failures of system calls;

- non-zero exit code of the program that was run.

Usually, a non-zero exit code of the program is a failure and means a
failure to the caller. Except that sometimes it does not. For example, the
exit code of merge programs (e.g. external merge drivers) conveys
information about how the merge failed, and not all exit calls are
actually failures.

Furthermore, the return value of run_command is sometimes used as exit
code by the caller.

This change arranges that the exit code of the program is returned as a
positive value, which can now be regarded as the "result" of the function.
System call failures continue to be reported as negative values.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-07-05 12:16:27 -07:00
Thomas Rast d824cbba02 Convert existing die(..., strerror(errno)) to die_errno()
Change calls to die(..., strerror(errno)) to use the new die_errno().

In the process, also make slight style adjustments: at least state
_something_ about the function that failed (instead of just printing
the pathname), and put paths in single quotes.

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-06-27 11:14:53 -07:00
Felipe Contreras 4b25d091ba Fix a bunch of pointer declarations (codestyle)
Essentially; s/type* /type */ as per the coding guidelines.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-05-01 15:17:31 -07:00
Junio C Hamano 1487eb68f7 Merge branch 'jk/maint-cleanup-after-exec-failure'
* jk/maint-cleanup-after-exec-failure:
  git: use run_command() to execute dashed externals
  run_command(): help callers distinguish errors
  run_command(): handle missing command errors more gracefully
  git: s/run_command/run_builtin/
2009-02-03 00:26:12 -08:00
Jeff King 45c0961c87 run_command(): handle missing command errors more gracefully
When run_command() was asked to run a non-existant command, its behavior
varied depending on the platform:

  - on POSIX systems, we would fork, and then after the execvp call
    failed, we could call die(), which prints a message to stderr and
    exits with code 128.

  - on Windows, we do a PATH lookup, realize the program isn't there, and
    then return ERR_RUN_COMMAND_FORK

The goal of this patch is to make it clear to callers that the specific
error was a missing command. To do this, we will return the error code
ERR_RUN_COMMAND_EXEC, which is already defined in run-command.h, checked
for in several places, but never actually gets set.

The new behavior is:

  - on POSIX systems, we exit the forked process with code 127 (the same
    as the shell uses to report missing commands). The parent process
    recognizes this code and returns an EXEC error. The stderr message is
    silenced, since the caller may be speculatively trying to run a
    command. Instead, we use trace_printf so that somebody interested in
    debugging can see the error that occured.

  - on Windows, we check errno, which is already set correctly by
    mingw_spawnvpe, and report an EXEC error instead of a FORK error

Thus it is safe to speculatively run a command:

  int r = run_command_v_opt(argv, 0);
  if (r == -ERR_RUN_COMMAND_EXEC)
	  /* oops, it wasn't found; try something else */
  else
	  /* we failed for some other reason, error is in r */

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-01-28 14:08:57 -08:00
Stephan Beyer 14e6298f12 run_hook(): allow more than 9 hook arguments
This is done using the ALLOC_GROW macro.

Signed-off-by: Stephan Beyer <s-beyer@gmx.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-01-17 17:57:15 -08:00
Stephan Beyer cf94ca8ea9 run_hook(): check the executability of the hook before filling argv
Signed-off-by: Stephan Beyer <s-beyer@gmx.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-01-17 17:16:44 -08:00
Stephan Beyer ae98a0089f Move run_hook() from builtin-commit.c into run-command.c (libgit)
A function that runs a hook is used in several Git commands.
builtin-commit.c has the one that is most general for cases without
piping. The one in builtin-gc.c prints some useful warnings.
This patch moves a merged version of these variants into libgit and
lets the other builtins use this libified run_hook().

The run_hook() function used in receive-pack.c feeds the standard
input of the pre-receive or post-receive hooks. This function is
renamed to run_receive_hook() because the libified run_hook() cannot
handle this.

Mentored-by: Daniel Barkalow <barkalow@iabervon.org>
Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Stephan Beyer <s-beyer@gmx.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-01-17 17:16:24 -08:00
Nanako Shiraishi 7996ff335e run-command.c: remove run_command_v_opt_cd()
This function is not used anywhere.

Johannes Sixt <johannes.sixt@telecom.at>:
> Future callers can use run_command_v_opt_cd_env() instead.

Signed-off-by: Nanako Shiraishi <nanako3@lavabit.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
2008-10-02 18:02:44 -07:00
Junio C Hamano 0208c9611a Merge branch 'jk/pager-swap'
* jk/pager-swap:
  spawn pager via run_command interface
  run-command: add pre-exec callback
2008-08-19 21:42:55 -07:00
Anders Melchiorsen 7d0b18a4da Add output flushing before fork()
This adds fflush(NULL) before fork() in start_command(), to keep
the generic interface safe.

A remaining use of fork() with no flushing is in a comment in
show_tree(). Rewrite that comment to use start_command().

Signed-off-by: Anders Melchiorsen <mail@cup.kalibalik.dk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-08-04 21:46:42 -07:00
Anders Melchiorsen 2c3766f06a Flush output in start_async
This prevents double output in case stdout is redirected.

Signed-off-by: Anders Melchiorsen <mail@cup.kalibalik.dk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-08-03 17:55:40 -07:00
Steffen Prohaska 108ac313f7 run-command (Windows): Run dashless "git <cmd>"
We prefer running the dashless form, and POSIX side already does so; we
should use it in MinGW's start_command(), too.

Signed-off-by: Steffen Prohaska <prohaska@zib.de>
Acked-by: Johannes Sixt <johannes.sixt@telecom.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-28 23:02:11 -07:00
Jeff King ccf08bc3d0 run-command: add pre-exec callback
This is a function provided by the caller which is called
_after_ the process is forked, but before the spawned
program is executed. On platforms (like mingw) where
subprocesses are forked and executed in a single call, the
preexec callback is simply ignored.

This will be used in the following patch to do some setup
for 'less' that must happen in the forked child.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-25 21:29:44 -07:00
Junio C Hamano bed625540a Merge branch 'qq/maint'
* qq/maint:
  run_command(): respect GIT_TRACE

Conflicts:

	run-command.c
2008-07-07 16:42:08 -07:00
Johannes Schindelin 8852f5d704 run_command(): respect GIT_TRACE
When GIT_TRACE is set, the user is most likely wanting to see an external
command that is about to be executed.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-07-07 13:16:33 -07:00
Johannes Sixt 7e5d776854 Windows: Implement a custom spawnve().
The problem with Windows's own implementation is that it tries to be
clever when a console program is invoked from a GUI application: In this
case it sometimes automatically allocates a new console window. As a
consequence, the IO channels of the spawned program are directed to the
console, but the invoking application listens on channels that are now
directed to nowhere.

In this implementation we use the lowlevel facilities of CreateProcess(),
which offers a flag to tell the system not to open a console. As a side
effect, only stdin, stdout, and stderr channels will be accessible from
C programs that are spawned. Other channels (file handles, pipe handles,
etc.) are still inherited by the spawned program, but it doesn't get
enough information to access them.

Johannes Schindelin integrated path quoting and unified the various
*execv* and *spawnv* helpers. Eric Raible suggested to also quote '{'.

Signed-off-by: Johannes Sixt <johannes.sixt@telecom.at>
2008-06-26 08:45:10 +02:00
Johannes Sixt 618ebe9ff9 Windows: Implement asynchronous functions as threads.
In upload-pack we must explicitly close the output channel of rev-list.
(On Unix, the channel is closed automatically because process that runs
rev-list terminates.)

Signed-off-by: Johannes Sixt <johannes.sixt@telecom.at>
2008-06-26 08:45:08 +02:00
Johannes Sixt ba26f296f9 Windows: Implement start_command().
On Windows, we have spawnv() variants to run a child process instead of
fork()/exec(). In order to attach pipe ends to stdin, stdout, and stderr,
we have to use this idiom:

    save1 = dup(1);
    dup2(pipe[1], 1);
    spawnv();
    dup2(save1, 1);
    close(pipe[1]);

assuming that the descriptors created by pipe() are not inheritable.

Signed-off-by: Johannes Sixt <johannes.sixt@telecom.at>
2008-06-23 13:40:31 +02:00
Christian Couder ce2cf27adc run-command: Redirect stderr to a pipe before redirecting stdout to stderr
With this patch, in the 'start_command' function after forking
we now take care of stderr in the child process before stdout.

This way if 'start_command' is called with a 'child_process'
argument like this:

	.err = -1;
	.stdout_to_stderr = 1;

then stderr will be redirected to a pipe before stdout is
redirected to stderr. So we can now get the process' stdout
from the pipe (as well as its stderr).

Earlier such a call would have redirected stdout to stderr
before stderr was itself redirected, and therefore stdout
would not have followed stderr, which would not have been
very useful anyway.

Update documentation in 'api-run-command.txt' accordingly.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Acked-by: Johannes Sixt <johannes.sixt@telecom.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-03-05 12:18:03 -08:00
Johannes Sixt c20181e3a3 start_command(), if .in/.out > 0, closes file descriptors, not the callers
Callers of start_command() can set the members .in and .out of struct
child_process to a value > 0 to specify that this descriptor is used as
the stdin or stdout of the child process.

Previously, if start_command() was successful, this descriptor was closed
upon return. Here we now make sure that the descriptor is also closed in
case of failures. All callers are updated not to close the file descriptor
themselves after start_command() was called.

Note that earlier run_gpg_verify() of git-verify-tag set .out = 1, which
worked because start_command() treated this as a special case, but now
this is incorrect because it closes the descriptor. The intent here is to
inherit stdout to the child, which is achieved by .out = 0.

Signed-off-by: Johannes Sixt <johannes.sixt@telecom.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-02-23 11:59:44 -08:00
Johannes Sixt e72ae28895 start_command(), .in/.out/.err = -1: Callers must close the file descriptor
By setting .in, .out, or .err members of struct child_process to -1, the
callers of start_command() can request that a pipe is allocated that talks
to the child process and one end is returned by replacing -1 with the
file descriptor.

Previously, a flag was set (for .in and .out, but not .err) to signal
finish_command() to close the pipe end that start_command() had handed out,
so it was optional for callers to close the pipe, and many already do so.
Now we make it mandatory to close the pipe.

Signed-off-by: Johannes Sixt <johannes.sixt@telecom.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-02-23 11:59:44 -08:00
Shawn O. Pearce b73a439759 run-command: Support sending stderr to /dev/null
Some callers may wish to redirect stderr to /dev/null in some
contexts, such as if they are executing a command only to get
the exit status and don't want users to see whatever output it
may produce as a side-effect of computing that exit status.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
2007-11-11 17:09:55 -08:00
Johannes Sixt 2d22c20830 Add infrastructure to run a function asynchronously.
This adds start_async() and finish_async(), which runs a function
asynchronously. Communication with the caller happens only via pipes.
For this reason, this implementation forks off a child process that runs
the function.

[sp: Style nit fixed by removing unnecessary block on if condition
     inside of start_async()]

Signed-off-by: Johannes Sixt <johannes.sixt@telecom.at>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
2007-10-21 01:30:41 -04:00
Johannes Sixt f3b33f1d22 Have start_command() create a pipe to read the stderr of the child.
This adds another stanza that allocates a pipe that is connected to the
child's stderr and that the caller can read from. In order to request this
pipe, the caller sets cmd->err to -1.

The implementation is not exactly modeled after the stdout case: For stdout
the caller can supply an existing file descriptor, but this facility is
nowhere needed in the stderr case. Additionally, the caller is required to
close cmd->err.

Signed-off-by: Johannes Sixt <johannes.sixt@telecom.at>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
2007-10-21 01:30:40 -04:00
Alex Riesen 3427b375b5 Allow environment variables to be unset in the processes started by run_command
To unset a variable, just specify its name, without "=". For example:

    const char *env[] = {"GIT_DIR=.git", "PWD", NULL};
    const char *argv[] = {"git-ls-files", "-s", NULL};
    int err = run_command_v_opt_cd_env(argv, RUN_GIT_CMD, ".", env);

The PWD will be unset before executing git-ls-files.

Signed-off-by: Alex Riesen <raa.lkml@gmail.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-05-23 22:38:44 -07:00
Alex Riesen ee4931486b Add ability to specify environment extension to run_command
There is no way to specify and override for the environment:
there'd be no user for it yet.

Signed-off-by: Alex Riesen <raa.lkml@gmail.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-05-23 22:38:44 -07:00
Alex Riesen 1568fea01e Add run_command_v_opt_cd: chdir into a directory before exec
It can make code simplier (no need to preserve cwd) and safer
(no chance the cwd of the current process is accidentally forgotten).

Signed-off-by: Alex Riesen <raa.lkml@gmail.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-05-23 22:38:44 -07:00
Shawn O. Pearce e4507ae84e Teach run-command to redirect stdout to /dev/null
Some run-command callers may wish to just discard any data that
is sent to stdout from the child.  This is a lot like our existing
no_stdin support, we just open /dev/null and duplicate the descriptor
into position.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-03-12 23:40:17 -07:00
Shawn O. Pearce f4bba25bdc Teach run-command about stdout redirection
Some potential callers of the run_command family of functions need
to control not only the stdin redirection of the child, but also
the stdout redirection of the child.  This can now be setup much
like the already existing stdin redirection.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-03-12 23:40:17 -07:00
Shawn O. Pearce 9dc09c7664 Simplify closing two fds at once in run-command.c
I started hacking on a change to add stdout redirection support to
the run_command family, but found I was using a lot of close calls
on two pipes in an array (such as for pipe).  So I'm doing a tiny
bit of refactoring first to make the next set of changes clearer.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-03-12 16:31:35 -07:00
Shawn O. Pearce 4919bf0354 Teach run_command how to setup a stdin pipe
Sometimes callers trying to use run_command to execute a child
process will want to setup a pipe or file descriptor to redirect
into the child's stdin.

This idea is completely stolen from builtin-bundle's fork_with_pipe,
written by Johannes Schindelin.  All credit (and blame) should lie
with Dscho.  ;-)

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-03-11 22:49:40 -07:00
Shawn O. Pearce ebcb5d16ca Split run_command into two halves (start/finish)
If the calling process wants to send data to stdin of a
child process it will need to arrange for a pipe and get
the child process running, feed data to it, then wait
for the child process to finish.  So we split the run
function into two halves, allowing callers to first
start the child then later finish it.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-03-11 22:49:37 -07:00
Shawn O. Pearce f1000898d4 Start defining a more sophisticated run_command
There are a number of places where we do some variation of
fork()+exec() but we also need to setup redirection in the process,
much like what run_command does for us already with its option flags.

It would be nice to reuse more of the run_command logic, especially
as that non-fork API helps us to port to odd platforms like Win32.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-03-11 22:49:34 -07:00
Shawn O. Pearce afdb269c76 Remove unused run_command variants
We don't actually use these va_list based variants of run_command
anymore.  I'm removing them before I make further improvements.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-03-11 22:49:31 -07:00
Shawn O. Pearce 95d3c4f546 Use /dev/null for update hook stdin.
Currently the update hook invoked by receive-pack has its stdin
connected to the pushing client.  The hook shouldn't attempt to
read from this stream, and doing so may consume data that was
meant for receive-pack.  Instead we should give the update hook
/dev/null as its stdin, ensuring that it always receives EOF and
doesn't disrupt the protocol if it attempts to read any data.

The post-update hook is similar, as it gets invoked with /dev/null
on stdin to prevent the hook from reading data from the client.
Previously we had invoked it with stdout also connected to /dev/null,
throwing away anything on stdout, to prevent client protocol errors.
Instead we should redirect stdout to stderr, like we do with the
update hook.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-12-30 22:22:14 -08:00
Shawn O. Pearce cd83c74cb3 Redirect update hook stdout to stderr.
If an update hook outputs to stdout then that output will be sent
back over the wire to the push client as though it were part of
the git protocol.  This tends to cause protocol errors on the
client end of the connection, as the hook output is not expected
in that context.  Most hook developers work around this by making
sure their hook outputs everything to stderr.

But hooks shouldn't need to perform such special behavior.  Instead
we can just dup stderr to stdout prior to invoking the update hook.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-12-30 22:22:14 -08:00
Shawn O. Pearce 9b0b50936e Remove unnecessary argc parameter from run_command_v.
The argc parameter is never used by the run_command_v family of
functions.  Instead they require that the passed argv[] be NULL
terminated so they can rely on the operating system's execvp
function to correctly pass the arguments to the new process.

Making the caller pass the argc is just confusing, as the caller
could be mislead into believing that the argc might take precendece
over the argv, or that the argv does not need to be NULL terminated.
So goodbye argc.  Don't come back.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-12-30 22:22:14 -08:00
Junio C Hamano 85023577a8 simplify inclusion of system header files.
This is a mechanical clean-up of the way *.c files include
system header files.

 (1) sources under compat/, platform sha-1 implementations, and
     xdelta code are exempt from the following rules;

 (2) the first #include must be "git-compat-util.h" or one of
     our own header file that includes it first (e.g. config.h,
     builtin.h, pkt-line.h);

 (3) system headers that are included in "git-compat-util.h"
     need not be included in individual C source files.

 (4) "git-compat-util.h" does not have to include subsystem
     specific header files (e.g. expat.h).

Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-12-20 09:51:35 -08:00
David Rientjes 6f002f984f use appropriate typedefs
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-08-15 16:12:09 -07:00
Junio C Hamano 9201c70742 Const tightening.
Mark Wooding noticed there was a type mismatch warning in git.c; this
patch does things slightly differently (mostly tightening const) and
was what I was holding onto, waiting for the setup-revisions change
to be merged into the master branch.

Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-03-05 02:47:29 -08:00
Michal Ostrowski 77cb17e940 Exec git programs without using PATH.
The git suite may not be in PATH (and thus programs such as
git-send-pack could not exec git-rev-list).  Thus there is a need for
logic that will locate these programs.  Modifying PATH is not
desirable as it result in behavior differing from the user's
intentions, as we may end up prepending "/usr/bin" to PATH.

- git C programs will use exec*_git_cmd() APIs to exec sub-commands.
- exec*_git_cmd() will execute a git program by searching for it in
  the following directories:
	1. --exec-path (as used by "git")
	2. The GIT_EXEC_PATH environment variable.
	3. $(gitexecdir) as set in Makefile (default value $(bindir)).
- git wrapper will modify PATH as before to enable shell scripts to
  invoke "git-foo" commands.

Ideally, shell scripts should use the git wrapper to become independent
of PATH, and then modifying PATH will not be necessary.

[jc: with minor updates after a brief review.]

Signed-off-by: Michal Ostrowski <mostrows@watson.ibm.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-01-13 16:49:01 -08:00
Daniel Barkalow 128aed684d Clean up file descriptors when calling hooks.
When calling post-update hook, don't leave stdin and stdout connected to
the pushing connection.

Signed-off-by: Daniel Barkalow <barkalow@iabervon.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2005-12-07 21:05:39 -08:00
Junio C Hamano 19614330dd receive-pack hooks updates.
The earlier one conflated update and post-update hooks for no
good reason.  Correct that ugly hack.  Now post-update hooks
will take the list of successfully updated refs.

Signed-off-by: Junio C Hamano <junkio@cox.net>
2005-08-02 22:51:09 -07:00
Josef Weidendorfer b1bf95bba2 [PATCH] Added hook in git-receive-pack
Just before updating a ref,

    $GIT_DIR/hooks/update refname old-sha1 new-sha1

is called if executable.  The hook can decline the ref to be
updated by exiting with a non-zero status, or allow it to be
updated by exiting with a zero status.  The mechanism also
allows e.g sending of a mail with pushed commits on the remote
repository.

Documentation update with an example hook is included.

jc: The credits of the basic idea and initial implementation go
to Josef, but I ended up rewriting major parts of his patch, so
bugs are all mine.  Also I changed the semantics for the hook
from his original version (which were post-update hook) so that
the hook can optionally decline to update the ref, and also can
be used to implement the overall cleanups.  The latter was
primarily to implement a suggestion from Linus that calling
update-server-info should be made optional.

Signed-off-by: Junio C Hamano <junkio@cox.net>
2005-07-31 23:30:59 -07:00