1 files changed, 165 insertions, 0 deletions
diff --git a/gnu/libexec/uucp/libunix/detach.c b/gnu/libexec/uucp/libunix/detach.c
new file mode 100644
index 000000000000..73144da001d4
--- /dev/null
+++ b/gnu/libexec/uucp/libunix/detach.c
@@ -0,0 +1,165 @@
+/* detach.c
+   Detach from the controlling terminal.
+
+   Copyright (C) 1992, 1993 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+   The author of the program may be contacted at ian@airs.com or
+   c/o Infinity Development Systems, P.O. Box 520, Waltham, MA 02254.
+   */
+
+#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 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);
+
+      ulog_id (getpid ());
+
+      /* Restore SIGHUP catcher if it wasn't being ignored.  */
+      if (! fignored)
+	usset_signal (SIGHUP, ussignal, TRUE, (boolean *) NULL);
+    }
+
+#if ! HAVE_SETSID && HAVE_TIOCNOTTY
+  /* Lose the original controlling terminal as well as our process
+     group.  If standard input has been reopened to /dev/null, this
+     will do no harm.  If another port has been opened to become the
+     controlling terminal, it should have been detached when it was
+     closed.  */
+  (void) ioctl (0, TIOCNOTTY, (char *) NULL);
+#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_SETPGRP
+  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.  */
+}