git/run-command.c, branch v2.12.0

Merge branch 'js/mingw-hooks-with-exe-suffix'

2017-02-02T21:36:57Z

Names of the various hook scripts must be spelled exactly, but on Windows, an .exe binary must be named with .exe suffix; notice $GIT_DIR/hooks/.exe as a valid hook. * js/mingw-hooks-with-exe-suffix: mingw: allow hooks to be .exe files

mingw: allow hooks to be .exe files

2017-01-30T16:49:43Z

Executable files in Windows need to have the extension '.exe', otherwise they do not work. Extend the hooks to not just look at the hard coded names, but also at the names extended by the custom STRIP_EXTENSION, which is defined as '.exe' in Windows. Signed-off-by: Johannes Schindelin Signed-off-by: Junio C Hamano

execv_dashed_external: wait for child on signal death

2017-01-09T21:41:40Z

When you hit ^C to interrupt a git command going to a pager, this usually leaves the pager running. But when a dashed external is in use, the pager ends up in a funny state and quits (but only after eating one more character from the terminal!). This fixes it. Explaining the reason will require a little background. When git runs a pager, it's important for the git process to hang around and wait for the pager to finish, even though it has no more data to feed it. This is because git spawns the pager as a child, and thus the git process is the session leader on the terminal. After it dies, the pager will finish its current read from the terminal (eating the one character), and then get EIO trying to read again. When you hit ^C, that sends SIGINT to git and to the pager, and it's a similar situation. The pager ignores it, but the git process needs to hang around until the pager is done. We addressed that long ago in a3da882120 (pager: do wait_for_pager on signal death, 2009-01-22). But when you have a dashed external (or an alias pointing to a builtin, which will re-exec git for the builtin), there's an extra process in the mix. For instance, running: $ git -c alias.l=log l will end up with a process tree like: git (parent) \ git-log (child) \ less (pager) If you hit ^C, SIGINT goes to all of them. The pager ignores it, and the child git process will end up in wait_for_pager(). But the parent git process will die, and the usual EIO trouble happens. So we really want the parent git process to wait_for_pager(), but of course it doesn't know anything about the pager at all, since it was started by the child. However, we can have it wait on the git-log child, which in turn is waiting on the pager. And that's what this patch does. There are a few design decisions here worth explaining: 1. The new feature is attached to run-command's clean_on_exit feature. Partly this is convenience, since that feature already has a signal handler that deals with child cleanup. But it's also a meaningful connection. The main reason that dashed externals use clean_on_exit is to bind the two processes together. If somebody kills the parent with a signal, we propagate that to the child (in this instance with SIGINT, we do propagate but it doesn't matter because the original signal went to the whole process group). Likewise, we do not want the parent to go away until the child has done so. In a traditional Unix world, we'd probably accomplish this binding by just having the parent execve() the child directly. But since that doesn't work on Windows, everything goes through run_command's more spawn-like interface. 2. We do _not_ automatically waitpid() on any clean_on_exit children. For dashed externals this makes sense; we know that the parent is doing nothing but waiting for the child to exit anyway. But with other children, it's possible that the child, after getting the signal, could be waiting on the parent to do something (like closing a descriptor). If we were to wait on such a child, we'd end up in a deadlock. So this errs on the side of caution, and lets callers enable the feature explicitly. 3. When we send children the cleanup signal, we send all the signals first, before waiting on any children. This is to avoid the case where one child might be waiting on another one to exit, causing a deadlock. We inform all of them that it's time to die before reaping any. In practice, there is only ever one dashed external run from a given process, so this doesn't matter much now. But it future-proofs us if other callers start using the wait_after_clean mechanism. There's no automated test here, because it would end up racy and unportable. But it's easy to reproduce the situation by running the log command given above and hitting ^C. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

run-command: add clean_on_exit_handler

2016-10-17T18:36:50Z

Some processes might want to perform cleanup tasks before Git kills them due to the 'clean_on_exit' flag. Let's give them an interface for doing this. The feature is used in a subsequent patch. Please note, that the cleanup callback is not executed if Git dies of a signal. The reason is that only "async-signal-safe" functions would be allowed to be call in that case. Since we cannot control what functions the callback will use, we will not support the case. See 507d7804 for more details. Helped-by: Johannes Sixt Signed-off-by: Lars Schneider Signed-off-by: Junio C Hamano

run-command: move check_pipe() from write_or_die to run_command

2016-10-17T18:36:49Z

Move check_pipe() to run_command and make it public. This is necessary to call the function from pkt-line in a subsequent patch. While at it, make async_exit() static to run_command.c as it is no longer used from outside. Signed-off-by: Lars Schneider Signed-off-by: Ramsay Jones Signed-off-by: Junio C Hamano

Merge branch 'ab/hooks'

2016-08-19T22:34:16Z

"git rev-parse --git-path hooks/" learned to take core.hooksPath configuration variable (introduced during 2.9 cycle) into account. * ab/hooks: rev-parse: respect core.hooksPath in --git-path

rev-parse: respect core.hooksPath in --git-path

2016-08-16T19:03:26Z

The idea of the --git-path option is not only to avoid having to prefix paths with the output of --git-dir all the time, but also to respect overrides for specific common paths inside the .git directory (e.g. `git rev-parse --git-path objects` will report the value of the environment variable GIT_OBJECT_DIRECTORY, if set). When introducing the core.hooksPath setting, we forgot to adjust git_path() accordingly. This patch fixes that. While at it, revert the special-casing of core.hooksPath in run-command.c, as it is now no longer needed. Signed-off-by: Johannes Schindelin Signed-off-by: Junio C Hamano

run-command: add pipe_command helper

2016-06-18T00:03:56Z

We already have capture_command(), which captures the stdout of a command in a way that avoids deadlocks. But sometimes we need to do more I/O, like capturing stderr as well, or sending data to stdin. It's easy to write code that deadlocks racily in these situations depending on how fast the command reads its input, or in which order it writes its output. Let's give callers an easy interface for doing this the right way, similar to what capture_command() did for the simple case. The whole thing is backed by a generic poll() loop that can feed an arbitrary number of buffers to descriptors, and fill an arbitrary number of strbufs from other descriptors. This seems like overkill, but the resulting code is actually a bit cleaner than just handling the three descriptors (because the output code for stdout/stderr is effectively duplicated, so being able to loop is a benefit). Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

Merge branch 'nd/error-errno'

2016-05-17T21:38:28Z

The code for warning_errno/die_errno has been refactored and a new error_errno() reporting helper is introduced. * nd/error-errno: (41 commits) wrapper.c: use warning_errno() vcs-svn: use error_errno() upload-pack.c: use error_errno() unpack-trees.c: use error_errno() transport-helper.c: use error_errno() sha1_file.c: use {error,die,warning}_errno() server-info.c: use error_errno() sequencer.c: use error_errno() run-command.c: use error_errno() rerere.c: use error_errno() and warning_errno() reachable.c: use error_errno() mailmap.c: use error_errno() ident.c: use warning_errno() http.c: use error_errno() and warning_errno() grep.c: use error_errno() gpg-interface.c: use error_errno() fast-import.c: use error_errno() entry.c: use error_errno() editor.c: use error_errno() diff-no-index.c: use error_errno() ...

Merge branch 'ab/hooks'

2016-05-17T21:38:17Z

A new configuration variable core.hooksPath allows customizing where the hook directory is. * ab/hooks: hooks: allow customizing where the hook directory is githooks.txt: minor improvements to the grammar & phrasing githooks.txt: amend dangerous advice about 'update' hook ACL githooks.txt: improve the intro section