xref: /onnv-gate/usr/src/lib/libast/common/comp/setsid.c (revision 12068:08a39a083754)
14887Schin /***********************************************************************
24887Schin *                                                                      *
34887Schin *               This software is part of the ast package               *
4*12068SRoger.Faulkner@Oracle.COM *          Copyright (c) 1985-2010 AT&T Intellectual Property          *
54887Schin *                      and is licensed under the                       *
64887Schin *                  Common Public License, Version 1.0                  *
78462SApril.Chin@Sun.COM *                    by AT&T Intellectual Property                     *
84887Schin *                                                                      *
94887Schin *                A copy of the License is available at                 *
104887Schin *            http://www.opensource.org/licenses/cpl1.0.txt             *
114887Schin *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
124887Schin *                                                                      *
134887Schin *              Information and Software Systems Research               *
144887Schin *                            AT&T Research                             *
154887Schin *                           Florham Park NJ                            *
164887Schin *                                                                      *
174887Schin *                 Glenn Fowler <gsf@research.att.com>                  *
184887Schin *                  David Korn <dgk@research.att.com>                   *
194887Schin *                   Phong Vo <kpv@research.att.com>                    *
204887Schin *                                                                      *
214887Schin ***********************************************************************/
224887Schin #pragma prototyped
234887Schin 
244887Schin #include <ast.h>
254887Schin 
264887Schin #if _lib_setsid
274887Schin 
284887Schin NoN(setsid)
294887Schin 
304887Schin #else
314887Schin 
324887Schin #include <ast_tty.h>
334887Schin #include <error.h>
344887Schin 
354887Schin /*
364887Schin  * become new process group leader and drop control tty
374887Schin  */
384887Schin 
394887Schin pid_t
404887Schin setsid(void)
414887Schin {
424887Schin 	int	pg;
434887Schin #ifdef TIOCNOTTY
444887Schin 	int	fd;
454887Schin #endif
464887Schin 
474887Schin 	/*
484887Schin 	 * become a new process group leader
494887Schin 	 */
504887Schin 
514887Schin 	if ((pg = getpid()) == getpgrp())
524887Schin 	{
534887Schin 		errno = EPERM;
544887Schin 		return(-1);
554887Schin 	}
564887Schin 	setpgid(pg, pg);
574887Schin #ifdef TIOCNOTTY
584887Schin 
594887Schin 	/*
604887Schin 	 * drop the control tty
614887Schin 	 */
624887Schin 
634887Schin 	if ((fd = open("/dev/tty", O_RDONLY)) >= 0)
644887Schin 	{
654887Schin 		ioctl(fd, TIOCNOTTY, 0);
664887Schin 		close(fd);
674887Schin 	}
684887Schin #else
694887Schin 
704887Schin 	/*
714887Schin 	 * second child in s5 to avoid reacquiring the control tty
724887Schin 	 */
734887Schin 
744887Schin #if _lib_fork && HUH920711 /* some s5's botch this */
754887Schin 	switch (fork())
764887Schin 	{
774887Schin 	case -1:
784887Schin 		exit(1);
794887Schin 	case 0:
804887Schin 		break;
814887Schin 	default:
824887Schin 		exit(0);
834887Schin 	}
844887Schin #endif
854887Schin 
864887Schin #endif
874887Schin 	return(pg);
884887Schin }
894887Schin 
904887Schin #endif
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