1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #if defined(LIBC_SCCS) && !defined(lint) 33 static char sccsid[] = "@(#)daemon.c 8.1 (Berkeley) 6/4/93"; 34 #endif /* LIBC_SCCS and not lint */ 35 #include <sys/cdefs.h> 36 __FBSDID("$FreeBSD$"); 37 38 #include "namespace.h" 39 #include <errno.h> 40 #include <fcntl.h> 41 #include <paths.h> 42 #include <stdlib.h> 43 #include <signal.h> 44 #include <unistd.h> 45 #include "un-namespace.h" 46 #include "libc_private.h" 47 48 int 49 daemon(int nochdir, int noclose) 50 { 51 struct sigaction osa, sa; 52 int fd; 53 pid_t newgrp; 54 int oerrno; 55 int osa_ok; 56 57 /* A SIGHUP may be thrown when the parent exits below. */ 58 sigemptyset(&sa.sa_mask); 59 sa.sa_handler = SIG_IGN; 60 sa.sa_flags = 0; 61 osa_ok = __libc_sigaction(SIGHUP, &sa, &osa); 62 63 switch (fork()) { 64 case -1: 65 return (-1); 66 case 0: 67 break; 68 default: 69 /* 70 * A fine point: _exit(0), not exit(0), to avoid triggering 71 * atexit(3) processing 72 */ 73 _exit(0); 74 } 75 76 newgrp = setsid(); 77 oerrno = errno; 78 if (osa_ok != -1) 79 __libc_sigaction(SIGHUP, &osa, NULL); 80 81 if (newgrp == -1) { 82 errno = oerrno; 83 return (-1); 84 } 85 86 if (!nochdir) 87 (void)chdir("/"); 88 89 if (!noclose && (fd = _open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 90 (void)_dup2(fd, STDIN_FILENO); 91 (void)_dup2(fd, STDOUT_FILENO); 92 (void)_dup2(fd, STDERR_FILENO); 93 if (fd > 2) 94 (void)_close(fd); 95 } 96 return (0); 97 } 98