Commit 4a88129a authored by Paul Eggert's avatar Paul Eggert

* callproc.c: Fix race that killed background processes.

(call_process): New arg TEMPFILE_INDEX.  Callers changed.
Record deleted process-id in critical section, not afterwards.
Don't mistakenly kill process created by a call-process invocation
that discards output and does not wait.

Fixes: debbugs:15144
parent 6ee60310
2013-08-21 Paul Eggert <eggert@cs.ucla.edu>
* callproc.c: Fix race that killed background processes (Bug#15144).
(call_process): New arg TEMPFILE_INDEX. Callers changed.
Record deleted process-id in critical section, not afterwards.
Don't mistakenly kill process created by a call-process invocation
that discards output and does not wait.
2013-08-21 Dmitry Antipov <dmantipov@yandex.ru>
Fix compilation with GC_MARK_STACK == GC_USE_GCPROS_AS_BEFORE
......
......@@ -102,7 +102,7 @@ enum
CALLPROC_FDS
};
static Lisp_Object call_process (ptrdiff_t, Lisp_Object *, int);
static Lisp_Object call_process (ptrdiff_t, Lisp_Object *, int, ptrdiff_t);
/* Block SIGCHLD. */
......@@ -248,14 +248,20 @@ usage: (call-process PROGRAM &optional INFILE DESTINATION DISPLAY &rest ARGS) *
report_file_error ("Opening process input file", infile);
record_unwind_protect_int (close_file_unwind, filefd);
UNGCPRO;
return unbind_to (count, call_process (nargs, args, filefd));
return unbind_to (count, call_process (nargs, args, filefd, -1));
}
/* Like Fcall_process (NARGS, ARGS), except use FILEFD as the input file.
If TEMPFILE_INDEX is nonnegative, it is the specpdl index of an
unwinder that is intended to remove the input temporary file; in
this case NARGS must be at least 2 and ARGS[1] is the file's name.
At entry, the specpdl stack top entry must be close_file_unwind (FILEFD). */
static Lisp_Object
call_process (ptrdiff_t nargs, Lisp_Object *args, int filefd)
call_process (ptrdiff_t nargs, Lisp_Object *args, int filefd,
ptrdiff_t tempfile_index)
{
Lisp_Object buffer, current_dir, path;
bool display_p;
......@@ -661,7 +667,22 @@ call_process (ptrdiff_t nargs, Lisp_Object *args, int filefd)
child_errno = errno;
if (pid > 0)
synch_process_pid = pid;
{
synch_process_pid = pid;
if (INTEGERP (buffer))
{
if (tempfile_index < 0)
record_deleted_pid (pid, Qnil);
else
{
eassert (1 < nargs);
record_deleted_pid (pid, args[1]);
clear_unwind_protect (tempfile_index);
}
synch_process_pid = 0;
}
}
unblock_child_signal ();
unblock_input ();
......@@ -1030,7 +1051,7 @@ If you quit, the process is killed with SIGINT, or SIGKILL if you quit again.
usage: (call-process-region START END PROGRAM &optional DELETE BUFFER DISPLAY &rest ARGS) */)
(ptrdiff_t nargs, Lisp_Object *args)
{
struct gcpro gcpro1, gcpro2;
struct gcpro gcpro1;
Lisp_Object infile, val;
ptrdiff_t count = SPECPDL_INDEX ();
Lisp_Object start = args[0];
......@@ -1061,8 +1082,7 @@ usage: (call-process-region START END PROGRAM &optional DELETE BUFFER DISPLAY &r
record_unwind_protect_int (close_file_unwind, fd);
}
val = infile;
GCPRO2 (infile, val);
GCPRO1 (infile);
if (nargs > 3 && !NILP (args[3]))
Fdelete_region (start, end);
......@@ -1079,16 +1099,7 @@ usage: (call-process-region START END PROGRAM &optional DELETE BUFFER DISPLAY &r
}
args[1] = infile;
val = call_process (nargs, args, fd);
if (!empty_input && 4 < nargs
&& (INTEGERP (CONSP (args[4]) ? XCAR (args[4]) : args[4])))
{
record_deleted_pid (synch_process_pid, infile);
synch_process_pid = 0;
clear_unwind_protect (count);
}
val = call_process (nargs, args, fd, empty_input ? -1 : count);
RETURN_UNGCPRO (unbind_to (count, val));
}
......
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