Fix bugs that can leak files or file descriptors on errors.
Don't unlink open temp files, as that's hard for users to diagnose
when things go awry (e.g., temp disk exhausted).
Don't bother to lock temp files. Check for invalid recursion.
* callproc.c (synch_process_fd): Remove. All uses removed.
(synch_process_tempfile): New var or macro.
(CALLPROC_STDOUT, CALLPROC_STDERR, CALLPROC_PIPEREAD, CALLPROC_FDS):
New constants.
(record_kill_process): New arg, the temp name. All callers changed.
(delete_temp_file): Now just a simple wrapper around unlink.
(call_process_kill): New arg, the call_process_fd array.
Close them all. Clear synch_process_pid. Remove the temp file,
or arrange for it to be removed.
(call_process_cleanup) [MSDOS]: Arg no longer contains file name;
that's been moved to synch_process_tempfile. Caller changed.
Do not remove the tempfile; that's now call_process_kill's
responsibility.
(call_process_cleanup) [!MSDOS]: Do not record unwind-protect for
call_process_kill; the caller now does that.
(call_process_cleanup): Do not close the process fd; that's now
call_process_kill's responsibility.
(Fcall_process): Implement via new function call_process, which
has most of the old body of Fcall_process, but with a different API.
(call_process): New function that does not open or close filefd if
it is nonnegative. Record which fds need to be closed, and let
call_process_kill close (and remove the tempfile, on MSDOS) on error.
Signal an error if invoked recursively (could be done via a hook).
Simplify creation of the tempfile in the MSDOS case.
Don't create the output file until after checking for the executable.
Report any failure to open /dev/null.
Don't open /dev/null for writing twice; once is enough.
Don't create pipe if all output is being discarded or sent to file.
Don't worry about setting up the coding system or reading from the
pipe if all output is being discarded.
Hoist fd_error local into top level, to lessen block nesting.
Don't record deleted pid here; now done by Fcall_process_region.
(Fcall_process) [MSDOS]: Report mktemp failure immediately,
and note its success in synch_process_tempfile.
Do not leak resources when child_setup fails.
(Fcall_process) [!MSDOS && !WINDOWSNT]: Remove duplicate assignment
to child_errno. Remove unnecessary close of fd0; it's close-on-exec.
(create_temp_file): Now returns open fd, with an additional
Lisp_Object * argument to return the name. All callers changed.
Do not close the file; rewind it instead, and leave it open for
the caller. Do not lock the temp file. Unwind-protect the file
and the file-descriptor.
(Fcall_process_region): If the input is /dev/null, unwind-protect it.
If an asynchrounous process, record it here, not in call_process.
(syms_of_callproc) [MSDOS]: Initialize synch_process_tempfile.
* eval.c (set_unwind_protect): New function.
* fileio.c (write_region): New function, generalized from the
old Fwrite_region. Do not lock temp files.
(Fwrite_region): Use it.
* lisp.h (set_unwind_protect, write_region): New decls.
* process.c: Include <verify.h>.
(make_process): Mark fds as initially closed.
(deleted_pid_list): Now a list of pid-filename pairs.
All uses changed.
(close_process_fd): New function.
(SUBPROCESS_STDIN, WRITE_TO_SUBPROCESS, READ_FROM_SUBPROCESS)
(SUBPROCESS_STDOUT, READ_FROM_EXEC_MONITOR, EXEC_MONITOR_OUTPUT):
New constants. Verify that their number matches PROCESS_OPEN_FDS.
(create_process, create_pty, Fmake_serial_process)
(server_accept_connection): Record which fds need to be closed,
and let deactivate_process close them.
(Fmake_network_process): Do not discard the unwind-protect
until it's safe to do so.
(deactivate_process): Close the fds opened by create_process etc.
(Fprocess_send_eof): Adjust to new way of recording open fds.
Report an error if /dev/null can't be opened, instead of aborting.
* process.h (PROCESS_OPEN_FDS): New constant.
(struct Lisp_Process): New member open_fds.
(record_kill_process, record_deleted_pid): Adjust signatures.
(record_deleted_pid): Move decl here ...
* syswait.h (record_deleted_pid): ... from here.
Fixes: debbugs:15035
Fixing this bug required some cleanup of the signal-handling code.
As a side effect, this change also fixes a longstanding rare race
condition whereby Emacs could mistakenly kill unrelated processes,
and it fixes a bug where a second C-g does not kill a recalcitrant
synchronous process in GNU/Linux and similar platforms.
The patch should also fix the last vestiges of Bug#9488,
a bug which has mostly been fixed on the trunk by other changes.
* callproc.c, process.h (synch_process_alive, synch_process_death)
(synch_process_termsig, sync_process_retcode):
Remove. All uses removed, to simplify analysis and so that
less consing is done inside critical sections.
* callproc.c (call_process_exited): Remove. All uses replaced
with !synch_process_pid.
* callproc.c (synch_process_pid, synch_process_fd): New static vars.
These take the role of what used to be in unwind-protect arg.
All uses changed.
(block_child_signal, unblock_child_signal):
New functions, to avoid races that could kill innocent-victim processes.
(call_process_kill, call_process_cleanup, Fcall_process): Use them.
(call_process_kill): Record killed processes as deleted, so that
zombies do not clutter up the system. Do this inside a critical
section, to avoid a race that would allow the clutter.
(call_process_cleanup): Fix code so that the second C-g works again
on common platforms such as GNU/Linux.
(Fcall_process): Create the child process in a critical section,
to fix a race condition. If creating an asynchronous process,
record it as deleted so that zombies do not clutter up the system.
Do unwind-protect for WINDOWSNT too, as that's simpler in the
light of these changes. Omit unnecessary call to emacs_close
before failure, as the unwind-protect code does that.
* callproc.c (call_process_cleanup):
* w32proc.c (waitpid): Simplify now that synch_process_alive is gone.
* process.c (record_deleted_pid): New function, containing
code refactored out of Fdelete_process.
(Fdelete_process): Use it.
(process_status_retrieved): Remove. All callers changed to use
child_status_change.
(record_child_status_change): Remove, folding its contents into ...
(handle_child_signal): ... this signal handler. Now, this
function is purely a handler for SIGCHLD, and is not called after
a synchronous waitpid returns; the synchronous code is moved to
wait_for_termination. There is no need to worry about reaping
more than one child now.
* sysdep.c (get_child_status, child_status_changed): New functions.
(wait_for_termination): Now takes int * status and bool
interruptible arguments, too. Do not record child status change;
that's now the caller's responsibility. All callers changed.
Reimplement in terms of get_child_status.
(wait_for_termination_1, interruptible_wait_for_termination):
Remove. All callers changed to use wait_for_termination.
* syswait.h: Include <stdbool.h>, for bool.
(record_child_status_change, interruptible_wait_for_termination):
Remove decls.
(record_deleted_pid, child_status_changed): New decls.
(wait_for_termination): Adjust to API changes noted above.
Fixes: debbugs:12980
* lisp.h, syswait.h (record_child_status_change, wait_for_termination)
(interruptible_wait_for_termination):
Move these decls from lisp.h to syswait.h, since they use pid_t.
Needed on FreeBSD; see Herbert J. Skuhra in
<http://lists.gnu.org/archive/html/emacs-devel/2012-09/msg00571.html>.
* callproc.c: Include syswait.h.
Without this change, 'configure' fails because the recently-added
wait3 prototype in config.h messes up later 'configure' tests.
Fix this problem by droping wait3 and WRETCODE, as they're
no longer needed on hosts that are current porting targets.
* configure.ac (wait3, WRETCODE): Remove, fixing a FIXME.
All uses changed to waitpid and WEXITSTATUS.
* src/syswait.h (WRETCODE): Remove, consistently with ../configure.ac.
always defined as int.
* s/netbsd.h (HAVE_UNION_WAIT, HAVE_WAIT_HEADER, WAIT_USE_INT):
* s/gnu.h (HAVE_WAIT_HEADER, WAIT_USE_INT, HAVE_UNION_WAIT):
* s/gnu-linux.h (HAVE_WAIT_HEADER):
* s/freebsd.h (HAVE_WAIT_HEADER):
* s/bsd-common.h (HAVE_UNION_WAIT):
* s/aix4-2.h (HAVE_WAIT_HEADER):
* m/mips.h (HAVE_UNION_WAIT):
* s/usg5-4.h (HAVE_WAIT_HEADER, WAITTYPE): Do not define, not used.
(COFF, static): Do not define, they are undefined later in the file.
* process.c (update_status): Don't use a union.
(status_convert):
(sigchld_handler): Use int instead of WAITTYPE.
* movemail.c (main): Use int instead of WAITTYPE.
(HAVE_SYS_WAIT_H): Undef for HPUX7, Convex.
[!HAVE_SYS_WAIT_H]: Define things unconditionally. More
perspicuous definitions.
(WTERMSIG): Fix bit pattern used.
