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detach.c revision 1.5.6.1 
      1 /*	$NetBSD: detach.c,v 1.5.6.1 2019/08/10 06:17:16 martin 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 1998-2019 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 <sys/cdefs.h>
     34 __RCSID("$NetBSD: detach.c,v 1.5.6.1 2019/08/10 06:17:16 martin Exp $");
     35 
     36 #include "portable.h"
     37 
     38 #include <stdio.h>
     39 
     40 #include <ac/stdlib.h>
     41 #include <ac/signal.h>
     42 #include <ac/socket.h>
     43 #include <ac/unistd.h>
     44 
     45 #include <sys/stat.h>
     46 #include <fcntl.h>
     47 
     48 #ifdef HAVE_SYS_FILE_H
     49 #include <sys/file.h>
     50 #endif
     51 #ifdef HAVE_SYS_IOCTL_H
     52 #include <sys/ioctl.h>
     53 #endif
     54 
     55 #include "lutil.h"
     56 
     57 int
     58 lutil_detach( int debug, int do_close )
     59 {
     60 	int		i, sd, nbits, pid;
     61 
     62 #ifdef HAVE_SYSCONF
     63 	nbits = sysconf( _SC_OPEN_MAX );
     64 #elif defined(HAVE_GETDTABLESIZE)
     65 	nbits = getdtablesize();
     66 #else
     67 	nbits = FD_SETSIZE;
     68 #endif
     69 
     70 #ifdef FD_SETSIZE
     71 	if ( nbits > FD_SETSIZE ) {
     72 		nbits = FD_SETSIZE;
     73 	}
     74 #endif /* FD_SETSIZE */
     75 
     76 	if ( debug == 0 ) {
     77 		for ( i = 0; i < 5; i++ ) {
     78 #ifdef HAVE_THR
     79 			pid = fork1();
     80 #else
     81 			pid = fork();
     82 #endif
     83 			switch ( pid )
     84 			{
     85 			case -1:
     86 				sleep( 5 );
     87 				continue;
     88 
     89 			case 0:
     90 				break;
     91 
     92 			default:
     93 				return pid;
     94 			}
     95 			break;
     96 		}
     97 
     98 		if ( (sd = open( "/dev/null", O_RDWR   )) == -1 &&
     99 			 (sd = open( "/dev/null", O_RDONLY )) == -1 &&
    100 			 /* Panic -- open *something* */
    101 			 (sd = open( "/",         O_RDONLY )) == -1    ) {
    102 			perror("/dev/null");
    103 		} else {
    104 			/* redirect stdin, stdout, stderr to /dev/null */
    105 			dup2( sd, STDIN_FILENO );
    106 			dup2( sd, STDOUT_FILENO );
    107 			dup2( sd, STDERR_FILENO );
    108 
    109 			switch( sd ) {
    110 			default:
    111 				close( sd );
    112 			case STDIN_FILENO:
    113 			case STDOUT_FILENO:
    114 			case STDERR_FILENO:
    115 				break;
    116 			}
    117 		}
    118 
    119 		if ( do_close ) {
    120 			/* close everything else */
    121 			for ( i = 0; i < nbits; i++ ) {
    122 				if( i != STDIN_FILENO &&
    123 					i != STDOUT_FILENO &&
    124 					i != STDERR_FILENO )
    125 				{
    126 					close( i );
    127 				}
    128 			}
    129 		}
    130 
    131 #ifdef CHDIR_TO_ROOT
    132 		(void) chdir( "/" );
    133 #endif
    134 
    135 #ifdef HAVE_SETSID
    136 		(void) setsid();
    137 #elif defined(TIOCNOTTY)
    138 		if ( (sd = open( "/dev/tty", O_RDWR )) != -1 ) {
    139 			(void) ioctl( sd, TIOCNOTTY, NULL );
    140 			(void) close( sd );
    141 		}
    142 #endif
    143 	}
    144 
    145 #ifdef SIGPIPE
    146 	(void) SIGNAL( SIGPIPE, SIG_IGN );
    147 #endif
    148 	return 0;
    149 }
    150