1 /*- 2 * Copyright (c) 1990, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #if defined(LIBC_SCCS) && !defined(lint) 31 static char sccsid[] = "@(#)daemon.c 8.1 (Berkeley) 6/4/93"; 32 #endif /* LIBC_SCCS and not lint */ 33 #include <sys/cdefs.h> 34 __FBSDID("$FreeBSD$"); 35 36 #include "namespace.h" 37 #include <errno.h> 38 #include <fcntl.h> 39 #include <paths.h> 40 #include <stdlib.h> 41 #include <signal.h> 42 #include <unistd.h> 43 #include "un-namespace.h" 44 #include "libc_private.h" 45 46 int 47 daemon(int nochdir, int noclose) 48 { 49 struct sigaction osa, sa; 50 int fd; 51 pid_t newgrp; 52 int oerrno; 53 int osa_ok; 54 55 /* A SIGHUP may be thrown when the parent exits below. */ 56 sigemptyset(&sa.sa_mask); 57 sa.sa_handler = SIG_IGN; 58 sa.sa_flags = 0; 59 osa_ok = __libc_sigaction(SIGHUP, &sa, &osa); 60 61 switch (fork()) { 62 case -1: 63 return (-1); 64 case 0: 65 break; 66 default: 67 /* 68 * A fine point: _exit(0), not exit(0), to avoid triggering 69 * atexit(3) processing 70 */ 71 _exit(0); 72 } 73 74 newgrp = setsid(); 75 oerrno = errno; 76 if (osa_ok != -1) 77 __libc_sigaction(SIGHUP, &osa, NULL); 78 79 if (newgrp == -1) { 80 errno = oerrno; 81 return (-1); 82 } 83 84 if (!nochdir) 85 (void)chdir("/"); 86 87 if (!noclose && (fd = _open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 88 (void)_dup2(fd, STDIN_FILENO); 89 (void)_dup2(fd, STDOUT_FILENO); 90 (void)_dup2(fd, STDERR_FILENO); 91 if (fd > 2) 92 (void)_close(fd); 93 } 94 return (0); 95 } 96