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 <sys/cdefs.h> 34 __SCCSID("@(#)daemon.c 8.1 (Berkeley) 6/4/93"); 35 #include "namespace.h" 36 #include <errno.h> 37 #include <fcntl.h> 38 #include <paths.h> 39 #include <stdlib.h> 40 #include <signal.h> 41 #include <unistd.h> 42 #include "un-namespace.h" 43 #include "libc_private.h" 44 45 int 46 daemonfd(int chdirfd, int nullfd) 47 { 48 struct sigaction osa, sa; 49 pid_t newgrp; 50 int oerrno; 51 int osa_ok; 52 53 /* A SIGHUP may be thrown when the parent exits below. */ 54 sigemptyset(&sa.sa_mask); 55 sa.sa_handler = SIG_IGN; 56 sa.sa_flags = 0; 57 osa_ok = __libc_sigaction(SIGHUP, &sa, &osa); 58 59 switch (fork()) { 60 case -1: 61 return (-1); 62 case 0: 63 break; 64 default: 65 /* 66 * A fine point: _exit(0), not exit(0), to avoid triggering 67 * atexit(3) processing 68 */ 69 _exit(0); 70 } 71 72 newgrp = setsid(); 73 oerrno = errno; 74 if (osa_ok != -1) 75 __libc_sigaction(SIGHUP, &osa, NULL); 76 77 if (newgrp == -1) { 78 errno = oerrno; 79 return (-1); 80 } 81 82 if (chdirfd != -1) 83 (void)fchdir(chdirfd); 84 85 if (nullfd != -1) { 86 (void)_dup2(nullfd, STDIN_FILENO); 87 (void)_dup2(nullfd, STDOUT_FILENO); 88 (void)_dup2(nullfd, STDERR_FILENO); 89 } 90 return (0); 91 } 92 93 int 94 daemon(int nochdir, int noclose) 95 { 96 int chdirfd, nullfd, ret; 97 98 if (!noclose) 99 nullfd = _open(_PATH_DEVNULL, O_RDWR, 0); 100 else 101 nullfd = -1; 102 103 if (!nochdir) 104 chdirfd = _open("/", O_EXEC); 105 else 106 chdirfd = -1; 107 108 ret = daemonfd(chdirfd, nullfd); 109 110 if (chdirfd != -1) 111 _close(chdirfd); 112 113 if (nullfd > 2) 114 _close(nullfd); 115 116 return (ret); 117 } 118