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detach.c revision 1.3 
      1 /*	$NetBSD: detach.c,v 1.3 2014/05/28 10:12:43 tron Exp $	*/
      2 
      3 /* detach.c -- routines to daemonize a process */
      4 /* $OpenLDAP$ */
      5 /* This work is part of OpenLDAP Software <http://www.openldap.org/>.
      6  *
      7  * Copyright 1998-2014 The OpenLDAP Foundation.
      8  * All rights reserved.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted only as authorized by the OpenLDAP
     12  * Public License.
     13  *
     14  * A copy of this license is available in the file LICENSE in the
     15  * top-level directory of the distribution or, alternatively, at
     16  * <http://www.OpenLDAP.org/license.html>.
     17  */
     18 /*
     19  * Copyright (c) 1990, 1994 Regents of the University of Michigan.
     20  * All rights reserved.
     21  *
     22  * Redistribution and use in source and binary forms are permitted
     23  * provided that this notice is preserved and that due credit is given
     24  * to the University of Michigan at Ann Arbor. The name of the University
     25  * may not be used to endorse or promote products derived from this
     26  * software without specific prior written permission. This software
     27  * is provided ``as is'' without express or implied warranty.
     28  */
     29 /* This work was originally developed by the University of Michigan
     30  * and distributed as part of U-MICH LDAP.
     31  */
     32 
     33 #include "portable.h"
     34 
     35 #include <stdio.h>
     36 
     37 #include <ac/stdlib.h>
     38 #include <ac/signal.h>
     39 #include <ac/socket.h>
     40 #include <ac/unistd.h>
     41 
     42 #include <sys/stat.h>
     43 #include <fcntl.h>
     44 
     45 #ifdef HAVE_SYS_FILE_H
     46 #include <sys/file.h>
     47 #endif
     48 #ifdef HAVE_SYS_IOCTL_H
     49 #include <sys/ioctl.h>
     50 #endif
     51 
     52 #include "lutil.h"
     53 
     54 int
     55 lutil_detach( int debug, int do_close )
     56 {
     57 	int		i, sd, nbits, pid;
     58 
     59 #ifdef HAVE_SYSCONF
     60 	nbits = sysconf( _SC_OPEN_MAX );
     61 #elif defined(HAVE_GETDTABLESIZE)
     62 	nbits = getdtablesize();
     63 #else
     64 	nbits = FD_SETSIZE;
     65 #endif
     66 
     67 #ifdef FD_SETSIZE
     68 	if ( nbits > FD_SETSIZE ) {
     69 		nbits = FD_SETSIZE;
     70 	}
     71 #endif /* FD_SETSIZE */
     72 
     73 	if ( debug == 0 ) {
     74 		for ( i = 0; i < 5; i++ ) {
     75 #ifdef HAVE_THR
     76 			pid = fork1();
     77 #else
     78 			pid = fork();
     79 #endif
     80 			switch ( pid )
     81 			{
     82 			case -1:
     83 				sleep( 5 );
     84 				continue;
     85 
     86 			case 0:
     87 				break;
     88 
     89 			default:
     90 				return pid;
     91 			}
     92 			break;
     93 		}
     94 
     95 		if ( (sd = open( "/dev/null", O_RDWR   )) == -1 &&
     96 			 (sd = open( "/dev/null", O_RDONLY )) == -1 &&
     97 			 /* Panic -- open *something* */
     98 			 (sd = open( "/",         O_RDONLY )) == -1    ) {
     99 			perror("/dev/null");
    100 		} else {
    101 			/* redirect stdin, stdout, stderr to /dev/null */
    102 			dup2( sd, STDIN_FILENO );
    103 			dup2( sd, STDOUT_FILENO );
    104 			dup2( sd, STDERR_FILENO );
    105 
    106 			switch( sd ) {
    107 			default:
    108 				close( sd );
    109 			case STDIN_FILENO:
    110 			case STDOUT_FILENO:
    111 			case STDERR_FILENO:
    112 				break;
    113 			}
    114 		}
    115 
    116 		if ( do_close ) {
    117 			/* close everything else */
    118 			for ( i = 0; i < nbits; i++ ) {
    119 				if( i != STDIN_FILENO &&
    120 					i != STDOUT_FILENO &&
    121 					i != STDERR_FILENO )
    122 				{
    123 					close( i );
    124 				}
    125 			}
    126 		}
    127 
    128 #ifdef CHDIR_TO_ROOT
    129 		(void) chdir( "/" );
    130 #endif
    131 
    132 #ifdef HAVE_SETSID
    133 		(void) setsid();
    134 #elif defined(TIOCNOTTY)
    135 		if ( (sd = open( "/dev/tty", O_RDWR )) != -1 ) {
    136 			(void) ioctl( sd, TIOCNOTTY, NULL );
    137 			(void) close( sd );
    138 		}
    139 #endif
    140 	}
    141 
    142 #ifdef SIGPIPE
    143 	(void) SIGNAL( SIGPIPE, SIG_IGN );
    144 #endif
    145 	return 0;
    146 }
    147