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 #include "namespace.h" 34 #include <errno.h> 35 #include <fcntl.h> 36 #include <paths.h> 37 #include <stdlib.h> 38 #include <signal.h> 39 #include <unistd.h> 40 #include "un-namespace.h" 41 #include "libc_private.h" 42 43 int 44 daemonfd(int chdirfd, int nullfd) 45 { 46 struct sigaction osa, sa; 47 pid_t newgrp; 48 int oerrno; 49 int osa_ok; 50 51 /* A SIGHUP may be thrown when the parent exits below. */ 52 sigemptyset(&sa.sa_mask); 53 sa.sa_handler = SIG_IGN; 54 sa.sa_flags = 0; 55 osa_ok = __libc_sigaction(SIGHUP, &sa, &osa); 56 57 switch (fork()) { 58 case -1: 59 return (-1); 60 case 0: 61 break; 62 default: 63 /* 64 * A fine point: _exit(0), not exit(0), to avoid triggering 65 * atexit(3) processing 66 */ 67 _exit(0); 68 } 69 70 newgrp = setsid(); 71 oerrno = errno; 72 if (osa_ok != -1) 73 __libc_sigaction(SIGHUP, &osa, NULL); 74 75 if (newgrp == -1) { 76 errno = oerrno; 77 return (-1); 78 } 79 80 if (chdirfd != -1) 81 (void)fchdir(chdirfd); 82 83 if (nullfd != -1) { 84 (void)_dup2(nullfd, STDIN_FILENO); 85 (void)_dup2(nullfd, STDOUT_FILENO); 86 (void)_dup2(nullfd, STDERR_FILENO); 87 } 88 return (0); 89 } 90 91 int 92 daemon(int nochdir, int noclose) 93 { 94 int chdirfd, nullfd, ret; 95 96 if (!noclose) 97 nullfd = _open(_PATH_DEVNULL, O_RDWR, 0); 98 else 99 nullfd = -1; 100 101 if (!nochdir) 102 chdirfd = _open("/", O_EXEC); 103 else 104 chdirfd = -1; 105 106 ret = daemonfd(chdirfd, nullfd); 107 108 if (chdirfd != -1) 109 _close(chdirfd); 110 111 if (nullfd > 2) 112 _close(nullfd); 113 114 return (ret); 115 } 116