1 /* $NetBSD: rumpuser_daemonize.c,v 1.7 2014/11/04 19:05:17 pooka Exp $ */ 2 3 /* 4 * Copyright (c) 2010 Antti Kantee. All Rights Reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 16 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 18 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #include "rumpuser_port.h" 29 30 #if !defined(lint) 31 __RCSID("$NetBSD: rumpuser_daemonize.c,v 1.7 2014/11/04 19:05:17 pooka Exp $"); 32 #endif /* !lint */ 33 34 #include <sys/types.h> 35 #include <sys/socket.h> 36 37 #include <errno.h> 38 #include <fcntl.h> 39 #include <stdint.h> 40 #include <stdio.h> 41 #include <unistd.h> 42 43 #include "rumpuser_int.h" 44 45 #if defined(HAVE_PATHS_H) 46 #include <paths.h> 47 #else 48 #define _PATH_DEVNULL "/dev/null" 49 #endif 50 51 static int isdaemonizing; 52 static int daemonpipe[2]; 53 54 #include <rump/rumpuser.h> 55 56 int 57 rumpuser_daemonize_begin(void) 58 { 59 ssize_t n; 60 int error; 61 int rv; 62 63 if (isdaemonizing) { 64 rv = EINPROGRESS; 65 goto out; 66 } 67 isdaemonizing = 1; 68 69 /* 70 * For daemons we need to fork. However, since we can't fork 71 * after rump_init (which creates threads), do it now. Add 72 * a little pipe trickery to make sure we don't exit until the 73 * service is fully inited (i.e. interlocked daemonization). 74 * Actually, use sucketpair since that allows to easily steer 75 * clear of the dreaded sigpipe. 76 * 77 * Note: We do *NOT* host chdir("/"). It's up to the caller to 78 * take care of that or not. 79 */ 80 if (socketpair(PF_LOCAL, SOCK_STREAM, 0, daemonpipe) == -1) { 81 rv = errno; 82 goto out; 83 } 84 85 switch (fork()) { 86 case 0: 87 if (setsid() == -1) { 88 rumpuser_daemonize_done(errno); 89 } 90 rv = 0; 91 break; 92 case -1: 93 rv = errno; 94 break; 95 default: 96 close(daemonpipe[1]); 97 n = recv(daemonpipe[0], &error, sizeof(error), MSG_NOSIGNAL); 98 if (n == -1) 99 error = errno; 100 else if (n != sizeof(error)) 101 error = ESRCH; 102 _exit(error); 103 /*NOTREACHED*/ 104 } 105 106 out: 107 ET(rv); 108 } 109 110 int 111 rumpuser_daemonize_done(int error) 112 { 113 ssize_t n; 114 int fd, rv = 0; 115 116 if (!isdaemonizing) { 117 rv = ENOENT; 118 goto outout; 119 } 120 121 if (error == 0) { 122 fd = open(_PATH_DEVNULL, O_RDWR); 123 if (fd == -1) { 124 error = errno; 125 goto out; 126 } 127 dup2(fd, STDIN_FILENO); 128 dup2(fd, STDOUT_FILENO); 129 dup2(fd, STDERR_FILENO); 130 if (fd > STDERR_FILENO) 131 close(fd); 132 } 133 134 out: 135 n = send(daemonpipe[1], &error, sizeof(error), MSG_NOSIGNAL); 136 if (n != sizeof(error)) { 137 rv = EPIPE; 138 } else if (n == -1) { 139 rv = errno; 140 } else { 141 close(daemonpipe[0]); 142 close(daemonpipe[1]); 143 } 144 145 outout: 146 ET(rv); 147 } 148