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Allow deleted processes to be reaped by SIGCHLD handler on MS-Windows.

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src/w32proc.c (new_child): Free up to 2 slots of dead processes at a
 time.  Improve diagnostics in DebPrint.
 (reader_thread): If cp->char_avail is NULL, set the FILE_AT_EOF
 flag, so that sys_select could have a chance of noticing that this
 process is dead, and call a SIGCHLD handler for it.  Improve
 diagnostics in DebPrint.
 (reap_subprocess): Reset the FILE_AT_EOF flag set by
 reader_thread.
 (sys_select): Watch a process whose procinfo.hProcess is non-NULL
 even if its char_avail is NULL.  Allows to reap subprocesses that
 were forcibly deleted by delete-process.  (Bug#13546)
This commit is contained in:
Eli Zaretskii 2013-02-15 11:41:31 +02:00
parent bcf7fe2aef
commit ef862e206a
2 changed files with 48 additions and 6 deletions
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12
src/ChangeLog
View file

@ -1,5 +1,17 @@
2013-02-15 Eli Zaretskii <eliz@gnu.org>
* w32proc.c (new_child): Free up to 2 slots of dead processes at a
time. Improve diagnostics in DebPrint.
(reader_thread): If cp->char_avail is NULL, set the FILE_AT_EOF
flag, so that sys_select could have a chance of noticing that this
process is dead, and call a SIGCHLD handler for it. Improve
diagnostics in DebPrint.
(reap_subprocess): Reset the FILE_AT_EOF flag set by
reader_thread.
(sys_select): Watch a process whose procinfo.hProcess is non-NULL
even if its char_avail is NULL. Allows to reap subprocesses that
were forcibly deleted by delete-process. (Bug#13546)
* w32.c (sys_socket, sys_bind, sys_connect, sys_gethostname)
(sys_gethostbyname, sys_getservbyname, sys_getpeername)
(sys_shutdown, sys_setsockopt, sys_listen, sys_getsockname)

42
src/w32proc.c
View file

@ -799,6 +799,9 @@ new_child (void)
goto Initialize;
if (child_proc_count == MAX_CHILDREN)
{
int i = 0;
child_process *dead_cp;
DebPrint (("new_child: No vacant slots, looking for dead processes\n"));
for (cp = child_procs + (child_proc_count-1); cp >= child_procs; cp--)
if (!CHILD_ACTIVE (cp) && cp->procinfo.hProcess)
@ -814,13 +817,23 @@ new_child (void)
if (status != STILL_ACTIVE
|| WaitForSingleObject (cp->procinfo.hProcess, 0) == WAIT_OBJECT_0)
{
DebPrint (("new_child: Freeing slot of dead process %d\n",
cp->procinfo.dwProcessId));
DebPrint (("new_child: Freeing slot of dead process %d, fd %d\n",
cp->procinfo.dwProcessId, cp->fd));
CloseHandle (cp->procinfo.hProcess);
cp->procinfo.hProcess = NULL;
CloseHandle (cp->procinfo.hThread);
cp->procinfo.hThread = NULL;
goto Initialize;
/* Free up to 2 dead slots at a time, so that if we
have a lot of them, they will eventually all be
freed when the tornado ends. */
if (i == 0)
dead_cp = cp;
else
{
cp = dead_cp;
goto Initialize;
}
i++;
}
}
}
@ -975,12 +988,24 @@ reader_thread (void *arg)
else
rc = _sys_read_ahead (cp->fd);
if (!CHILD_ACTIVE (cp) && cp->procinfo.hProcess && cp->fd >= 0)
{
/* Somebody already called delete_child on this child, since
only delete_child zeroes out cp->char_avail. This means
no one will read from cp->fd and will not set the
FILE_AT_EOF flag, therefore preventing sys_select from
noticing that the process died. Set the flag here
instead. */
fd_info[cp->fd].flags |= FILE_AT_EOF;
}
/* The name char_avail is a misnomer - it really just means the
read-ahead has completed, whether successfully or not. */
if (!SetEvent (cp->char_avail))
{
DebPrint (("reader_thread.SetEvent failed with %lu for fd %ld\n",
GetLastError (), cp->fd));
DebPrint (("reader_thread.SetEvent(0x%x) failed with %lu for fd %ld (PID %d)\n",
(DWORD_PTR)cp->char_avail, GetLastError (),
cp->fd, cp->pid));
return 1;
}
@ -1141,6 +1166,11 @@ reap_subprocess (child_process *cp)
register_child has not been called. */
if (cp->fd == -1)
delete_child (cp);
else
{
/* Reset the flag set by reader_thread. */
fd_info[cp->fd].flags &= ~FILE_AT_EOF;
}
}
/* Wait for any of our existing child processes to die
@ -1925,7 +1955,7 @@ sys_select (int nfds, SELECT_TYPE *rfds, SELECT_TYPE *wfds, SELECT_TYPE *efds,
/* Some child_procs might be sockets; ignore them. Also some
children may have died already, but we haven't finished reading
the process output; ignore them too. */
if (CHILD_ACTIVE (cp) && cp->procinfo.hProcess
if ((CHILD_ACTIVE (cp) || cp->procinfo.hProcess)
&& (cp->fd < 0
|| (fd_info[cp->fd].flags & FILE_SEND_SIGCHLD) == 0
|| (fd_info[cp->fd].flags & FILE_AT_EOF) != 0)