new detach code from HEAD

libraries/liblutil/detach.c

@@ -0,0 +1,125 @@
+/* $OpenLDAP$ */
+/*
+ * Copyright (c) 1990, 1994 Regents of the University of Michigan.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that this notice is preserved and that due credit is given
+ * to the University of Michigan at Ann Arbor. The name of the University
+ * may not be used to endorse or promote products derived from this
+ * software without specific prior written permission. This software
+ * is provided ``as is'' without express or implied warranty.
+ */
+
+#include "portable.h"
+
+#include <stdio.h>
+
+#include <ac/stdlib.h>
+#include <ac/signal.h>
+#include <ac/socket.h>
+#include <ac/unistd.h>
+
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#ifdef HAVE_SYS_FILE_H
+#include <sys/file.h>
+#endif
+#ifdef HAVE_SYS_IOCTL_H
+#include <sys/ioctl.h>
+#endif
+
+#include "lutil.h"
+
+void
+lutil_detach( int debug, int do_close )
+{
+	int		i, sd, nbits;
+
+#ifdef HAVE_SYSCONF
+	nbits = sysconf( _SC_OPEN_MAX );
+#elif HAVE_GETDTABLESIZE
+	nbits = getdtablesize();
+#else
+	nbits = FD_SETSIZE;
+#endif
+
+#ifdef FD_SETSIZE
+	if ( nbits > FD_SETSIZE ) {
+		nbits = FD_SETSIZE;
+	}
+#endif /* FD_SETSIZE */
+
+	if ( debug == 0 ) {
+		for ( i = 0; i < 5; i++ ) {
+#if HAVE_THR
+			switch ( fork1() )
+#else
+			switch ( fork() )
+#endif
+			{
+			case -1:
+				sleep( 5 );
+				continue;
+
+			case 0:
+				break;
+
+			default:
+				_exit( EXIT_SUCCESS );
+			}
+			break;
+		}
+
+		if ( (sd = open( "/dev/null", O_RDWR   )) == -1 &&
+			 (sd = open( "/dev/null", O_RDONLY )) == -1 &&
+			 /* Panic -- open *something* */
+			 (sd = open( "/",         O_RDONLY )) == -1    ) {
+			perror("/dev/null");
+		} else {
+			/* redirect stdin, stdout, stderr to /dev/null */
+			dup2( sd, STDIN_FILENO );
+			dup2( sd, STDOUT_FILENO );
+			dup2( sd, STDERR_FILENO );
+
+			switch( sd ) {
+			default:
+				close( sd );
+			case STDIN_FILENO:
+			case STDOUT_FILENO:
+			case STDERR_FILENO:
+				break;
+			}
+		}
+
+		if ( do_close ) {
+			/* close everything else */
+			for ( i = 0; i < nbits; i++ ) {
+				if( i != STDIN_FILENO &&
+					i != STDOUT_FILENO && 
+					i != STDERR_FILENO )
+				{
+					close( i );
+				}
+			}
+		}
+
+#ifdef CHDIR_TO_ROOT
+		(void) chdir( "/" );
+#endif
+
+#ifdef HAVE_SETSID
+		(void) setsid();
+#elif TIOCNOTTY
+		if ( (sd = open( "/dev/tty", O_RDWR )) != -1 ) {
+			(void) ioctl( sd, TIOCNOTTY, NULL );
+			(void) close( sd );
+		}
+#endif
+	} 
+
+#ifdef SIGPIPE
+	(void) SIGNAL( SIGPIPE, SIG_IGN );
+#endif
+}