1 /* $NetBSD: rumpuser_daemonize.c,v 1.10 2024/04/04 21:19:25 riastradh 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 1.10 2024/04/04 21:19:25 riastradh 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 static int
openstdoutstderr(void)57 openstdoutstderr(void)
58 {
59 char path[PATH_MAX];
60 int fd;
61
62 if (getenv_r("RUMP_STDOUT", path, sizeof(path)) == 0) {
63 if ((fd = open(path, O_WRONLY|O_CREAT)) == -1)
64 return -1;
65 dup2(fd, STDOUT_FILENO);
66 (void)close(fd);
67 }
68 if (getenv_r("RUMP_STDERR", path, sizeof(path)) == 0) {
69 if ((fd = open(path, O_WRONLY|O_CREAT)) == -1)
70 return -1;
71 dup2(fd, STDERR_FILENO);
72 (void)close(fd);
73 }
74 return 0;
75 }
76
77 int
rumpuser_daemonize_begin(void)78 rumpuser_daemonize_begin(void)
79 {
80 ssize_t n;
81 int error;
82 int rv;
83
84 if (isdaemonizing) {
85 rv = EINPROGRESS;
86 goto out;
87 }
88 isdaemonizing = 1;
89
90 /*
91 * For daemons we need to fork. However, since we can't fork
92 * after rump_init (which creates threads), do it now. Add
93 * a little pipe trickery to make sure we don't exit until the
94 * service is fully inited (i.e. interlocked daemonization).
95 * Actually, use socketpair since that allows to easily steer
96 * clear of the dreaded sigpipe.
97 *
98 * Note: We do *NOT* host chdir("/"). It's up to the caller to
99 * take care of that or not.
100 */
101 if (socketpair(PF_LOCAL, SOCK_STREAM, 0, daemonpipe) == -1) {
102 rv = errno;
103 goto out;
104 }
105
106 if (openstdoutstderr() == -1) {
107 rv = errno;
108 (void)close(daemonpipe[0]);
109 (void)close(daemonpipe[1]);
110 goto out;
111 }
112
113 switch (fork()) {
114 case 0:
115 if (setsid() == -1) {
116 rumpuser_daemonize_done(errno);
117 }
118 rv = 0;
119 break;
120 case -1:
121 rv = errno;
122 break;
123 default:
124 close(daemonpipe[1]);
125 n = recv(daemonpipe[0], &error, sizeof(error), MSG_NOSIGNAL);
126 if (n == -1)
127 error = errno;
128 else if (n != sizeof(error))
129 error = ESRCH;
130 _exit(error);
131 /*NOTREACHED*/
132 }
133
134 out:
135 ET(rv);
136 }
137
138 int
rumpuser_daemonize_done(int error)139 rumpuser_daemonize_done(int error)
140 {
141 ssize_t n;
142 int fd, rv = 0;
143
144 if (!isdaemonizing) {
145 rv = ENOENT;
146 goto outout;
147 }
148
149 if (error == 0) {
150 fd = open(_PATH_DEVNULL, O_RDWR);
151 if (fd == -1) {
152 error = errno;
153 goto out;
154 }
155 dup2(fd, STDIN_FILENO);
156 if (getenv("RUMP_STDOUT") == NULL)
157 dup2(fd, STDOUT_FILENO);
158 if (getenv("RUMP_STDERR") == NULL)
159 dup2(fd, STDERR_FILENO);
160 if (fd > STDERR_FILENO)
161 close(fd);
162 }
163
164 fflush(stdout);
165 fflush(stderr);
166
167 out:
168 n = send(daemonpipe[1], &error, sizeof(error), MSG_NOSIGNAL);
169 if (n != sizeof(error)) {
170 rv = EPIPE;
171 } else if (n == -1) {
172 rv = errno;
173 } else {
174 close(daemonpipe[0]);
175 close(daemonpipe[1]);
176 }
177
178 outout:
179 ET(rv);
180 }
181