1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1990, 1993 The Regents of the University of California. 5 * Copyright (c) 2017 Mariusz Zaborski <oshogbo@FreeBSD.org> 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #if defined(LIBC_SCCS) && !defined(lint) 34 static char sccsid[] = "@(#)daemon.c 8.1 (Berkeley) 6/4/93"; 35 #endif /* LIBC_SCCS and not lint */ 36 #include <sys/cdefs.h> 37 __FBSDID("$FreeBSD$"); 38 39 #include "namespace.h" 40 #include <errno.h> 41 #include <fcntl.h> 42 #include <paths.h> 43 #include <stdlib.h> 44 #include <signal.h> 45 #include <unistd.h> 46 #include "un-namespace.h" 47 #include "libc_private.h" 48 49 int 50 daemonfd(int chdirfd, int nullfd) 51 { 52 struct sigaction osa, sa; 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 (chdirfd != -1) 87 (void)fchdir(chdirfd); 88 89 if (nullfd != -1) { 90 (void)_dup2(nullfd, STDIN_FILENO); 91 (void)_dup2(nullfd, STDOUT_FILENO); 92 (void)_dup2(nullfd, STDERR_FILENO); 93 } 94 return (0); 95 } 96 97 int 98 daemon(int nochdir, int noclose) 99 { 100 int chdirfd, nullfd, ret; 101 102 if (!noclose) 103 nullfd = _open(_PATH_DEVNULL, O_RDWR, 0); 104 else 105 nullfd = -1; 106 107 if (!nochdir) 108 chdirfd = _open("/", O_EXEC); 109 else 110 chdirfd = -1; 111 112 ret = daemonfd(chdirfd, nullfd); 113 114 if (chdirfd != -1) 115 _close(chdirfd); 116 117 if (nullfd > 2) 118 _close(nullfd); 119 120 return (ret); 121 } 122