182 lines
4.9 KiB
C
182 lines
4.9 KiB
C
/* detach.c
|
||
Detach from the controlling terminal.
|
||
|
||
Copyright (C) 1992, 1993, 1995 Ian Lance Taylor
|
||
|
||
This file is part of the Taylor UUCP package.
|
||
|
||
This program is free software; you can redistribute it and/or
|
||
modify it under the terms of the GNU General Public License as
|
||
published by the Free Software Foundation; either version 2 of the
|
||
License, or (at your option) any later version.
|
||
|
||
This program is distributed in the hope that it will be useful, but
|
||
WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||
General Public License for more details.
|
||
|
||
You should have received a copy of the GNU General Public License
|
||
along with this program; if not, write to the Free Software
|
||
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
|
||
|
||
The author of the program may be contacted at ian@airs.com or
|
||
c/o Cygnus Support, 48 Grove Street, Somerville, MA 02144.
|
||
*/
|
||
|
||
#include "uucp.h"
|
||
|
||
#include "uudefs.h"
|
||
#include "system.h"
|
||
#include "sysdep.h"
|
||
|
||
#include <errno.h>
|
||
|
||
#if HAVE_SYS_IOCTL_H
|
||
#include <sys/ioctl.h>
|
||
#endif
|
||
|
||
#ifdef TIOCNOTTY
|
||
#define HAVE_TIOCNOTTY 1
|
||
#else
|
||
#define HAVE_TIOCNOTTY 0
|
||
#endif
|
||
|
||
#if HAVE_FCNTL_H
|
||
#include <fcntl.h>
|
||
#else
|
||
#if HAVE_SYS_FILE_H
|
||
#include <sys/file.h>
|
||
#endif
|
||
#endif
|
||
|
||
#ifndef O_RDONLY
|
||
#define O_RDONLY 0
|
||
#define O_WRONLY 1
|
||
#define O_RDWR 2
|
||
#endif
|
||
|
||
#if HAVE_BROKEN_SETSID
|
||
#undef HAVE_SETSID
|
||
#define HAVE_SETSID 0
|
||
#endif
|
||
|
||
/* Detach from the controlling terminal. This is called by uucico if
|
||
it is calling out to another system, so that it can receive SIGHUP
|
||
signals from the port it calls out on. It is also called by uucico
|
||
just before it starts uuxqt, so that uuxqt is completely
|
||
independent of the terminal. */
|
||
|
||
void
|
||
usysdep_detach ()
|
||
{
|
||
pid_t igrp;
|
||
|
||
/* Make sure that we can open the log file. We do this now so that,
|
||
if we can't, a message will be written to stderr. After we leave
|
||
this routine, stderr will be closed. */
|
||
ulog (LOG_NORMAL, (const char *) NULL);
|
||
|
||
/* Make sure we are not a process group leader. */
|
||
#if HAVE_BSD_PGRP
|
||
igrp = getpgrp (0);
|
||
#else
|
||
igrp = getpgrp ();
|
||
#endif
|
||
|
||
if (igrp == getpid ())
|
||
{
|
||
boolean fignored;
|
||
pid_t ipid;
|
||
|
||
/* Ignore SIGHUP, since our process group leader is about to
|
||
die. */
|
||
usset_signal (SIGHUP, SIG_IGN, FALSE, &fignored);
|
||
|
||
ipid = ixsfork ();
|
||
if (ipid < 0)
|
||
ulog (LOG_FATAL, "fork: %s", strerror (errno));
|
||
|
||
if (ipid != 0)
|
||
_exit (EXIT_SUCCESS);
|
||
|
||
/* We'll always wind up as a child of process number 1, right?
|
||
Right? We have to wait for our parent to die before
|
||
reenabling SIGHUP. */
|
||
while (getppid () != 1)
|
||
sleep (1);
|
||
|
||
ipid = getpid ();
|
||
ulog_id (ipid);
|
||
|
||
/* Restore SIGHUP catcher if it wasn't being ignored. */
|
||
if (! fignored)
|
||
usset_signal (SIGHUP, ussignal, TRUE, (boolean *) NULL);
|
||
|
||
DEBUG_MESSAGE2 (DEBUG_PORT,
|
||
"usysdep_detach: Forked; old PID %ld, new pid %ld",
|
||
(long) igrp, (long) ipid);
|
||
}
|
||
|
||
#if ! HAVE_SETSID && HAVE_TIOCNOTTY
|
||
/* Lose the original controlling terminal as well as our process
|
||
group. */
|
||
{
|
||
int o;
|
||
|
||
o = open ((char *) "/dev/tty", O_RDONLY);
|
||
if (o >= 0)
|
||
{
|
||
(void) ioctl (o, TIOCNOTTY, (char *) NULL);
|
||
(void) close (o);
|
||
}
|
||
}
|
||
#endif /* ! HAVE_SETSID && HAVE_TIOCNOTTY */
|
||
|
||
/* Close stdin, stdout and stderr and reopen them on /dev/null, to
|
||
make sure we have no connection at all to the terminal. */
|
||
(void) close (0);
|
||
(void) close (1);
|
||
(void) close (2);
|
||
if (open ((char *) "/dev/null", O_RDONLY) != 0
|
||
|| open ((char *) "/dev/null", O_WRONLY) != 1
|
||
|| open ((char *) "/dev/null", O_WRONLY) != 2)
|
||
ulog (LOG_FATAL, "open (/dev/null): %s", strerror (errno));
|
||
|
||
#if HAVE_SETSID
|
||
|
||
/* Under POSIX the setsid call creates a new session for which we
|
||
are the process group leader. It also detaches us from our
|
||
controlling terminal. */
|
||
if (setsid () < 0)
|
||
ulog (LOG_ERROR, "setsid: %s", strerror (errno));
|
||
|
||
#else /* ! HAVE_SETSID */
|
||
|
||
#if ! HAVE_SETPGRP
|
||
#error Cannot detach from controlling terminal
|
||
#endif
|
||
|
||
/* If we don't have setsid, we must use setpgrp. On an old System V
|
||
system setpgrp will make us the leader of a new process group and
|
||
detach the controlling terminal. On an old BSD system the call
|
||
setpgrp (0, 0) will set our process group to 0 so that we can
|
||
acquire a new controlling terminal (TIOCNOTTY may or may not have
|
||
already done that anyhow). */
|
||
#if HAVE_BSD_PGRP
|
||
if (setpgrp (0, 0) < 0)
|
||
#else
|
||
if (setpgrp () < 0)
|
||
#endif
|
||
{
|
||
/* Some systems seem to give EPERM errors inappropriately. */
|
||
if (errno != EPERM)
|
||
ulog (LOG_ERROR, "setpgrp: %s", strerror (errno));
|
||
}
|
||
|
||
#endif /* ! HAVE_SETSID */
|
||
|
||
/* At this point we have completely detached from our controlling
|
||
terminal. The next terminal device we open will probably become
|
||
our controlling terminal. */
|
||
}
|