1 /* $NetBSD: detach.c,v 1.2 2017/01/28 21:31:50 christos Exp $ */
2
3 /*-
4 * Copyright (c) 2015
5 * Cryptonector LLC. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Cryptonector LLC may not be used to endorse or promote products
16 * derived from this software without specific prior written
17 * permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #include <config.h>
33 #include <errno.h>
34 #include <fcntl.h>
35 #ifdef WIN32
36 #include <io.h>
37 #include <stdlib.h>
38 #else
39 #include <unistd.h>
40 #endif
41 #include <krb5/roken.h>
42
43 #ifdef WIN32
44 #define dup2 _dup2
45 #endif
46
47 static int pipefds[2] = {-1, -1};
48
49 ROKEN_LIB_FUNCTION void ROKEN_LIB_CALL
roken_detach_prep(int argc,char ** argv,char * special_arg)50 roken_detach_prep(int argc, char **argv, char *special_arg)
51 {
52 pid_t child;
53 char buf[1];
54 ssize_t bytes;
55 int status;
56
57 pipefds[0] = -1;
58 pipefds[1] = -1;
59
60 #ifdef WIN32
61 if (_pipe(pipefds, 4, O_BINARY) == -1)
62 err(1, "failed to setup to detach daemon (_pipe failed)");
63 #else
64 if (pipe(pipefds) == -1)
65 err(1, "failed to setup to detach daemon (pipe failed)");
66 #endif
67
68 #ifndef WIN32
69 fflush(stdout);
70 child = fork();
71 #else
72 {
73 intptr_t child_handle;
74 int write_side;
75 size_t i;
76 char *fildes;
77 char **new_argv;
78
79 new_argv = calloc(argc + 2, sizeof(*new_argv));
80 if (new_argv == NULL)
81 err(1, "Out of memory");
82
83 write_side = _dup(pipefds[1]); /* The new fd will be inherited */
84 if (write_side == -1)
85 err(1, "Out of memory");
86
87 if (asprintf(&fildes, "%d", write_side) == -1 ||
88 fildes == NULL)
89 err(1, "failed to setup to detach daemon (_dup failed)");
90
91 new_argv[0] = argv[0];
92 new_argv[1] = special_arg;
93 new_argv[2] = fildes;
94 for (i = 1; argv[i] != NULL; i++)
95 new_argv[i + 1] = argv[i];
96 new_argv[argc + 2] = NULL;
97
98 _flushall();
99 child_handle = spawnvp(_P_NOWAIT, argv[0], new_argv);
100 if (child_handle == -1)
101 child = (pid_t)-1;
102 else
103 child = GetProcessId((HANDLE)child_handle);
104 }
105 #endif
106 if (child == (pid_t)-1)
107 err(1, "failed to setup to fork daemon (fork failed)");
108
109 #ifndef WIN32
110 if (child == 0) {
111 int fd;
112
113 (void) close(pipefds[0]);
114 pipefds[0] = -1;
115 /*
116 * Keep stdout/stderr for now so output and errors prior to
117 * detach_finish() can be seen by the user.
118 */
119 fd = open(_PATH_DEVNULL, O_RDWR, 0);
120 if (fd == -1)
121 err(1, "failed to open /dev/null");
122 (void) dup2(fd, STDIN_FILENO);
123 if (fd > STDERR_FILENO)
124 (void) close(fd);
125 return;
126 }
127 #endif
128
129 (void) close(pipefds[1]);
130 pipefds[1] = -1;
131 do {
132 bytes = read(pipefds[0], buf, sizeof(buf));
133 } while (bytes == -1 && errno == EINTR);
134 (void) close(pipefds[0]);
135 pipefds[0] = -1;
136 if (bytes == -1) {
137 /*
138 * No need to wait for the process. We've killed it. If it
139 * doesn't want to exit, we'd have to wait potentially forever,
140 * but we want to indicate failure to the user as soon as
141 * possible. A wait with timeout would end the same way
142 * (attempting to kill the process).
143 */
144 err(1, "failed to setup daemon child (read from child pipe)");
145 }
146 if (bytes == 0) {
147 warnx("daemon child preparation failed, waiting for child");
148 status = wait_for_process(child);
149 if (SE_IS_ERROR(status) || SE_PROCSTATUS(status) != 0)
150 errx(SE_PROCSTATUS(status),
151 "daemon child preparation failed (child exited)");
152 }
153 _exit(0);
154 }
155
156 #ifdef WIN32
157 #ifdef dup2
158 #undef dup2
159 #endif
160 #define dup2 _dup2
161 #endif
162
163 ROKEN_LIB_FUNCTION void ROKEN_LIB_CALL
roken_detach_finish(const char * dir,int daemon_child_fd)164 roken_detach_finish(const char *dir, int daemon_child_fd)
165 {
166 char buf[1] = "";
167 ssize_t bytes;
168 int fd;
169
170 rk_pidfile(NULL);
171 if (pipefds[1] == -1 && daemon_child_fd != -1)
172 pipefds[1] = daemon_child_fd;
173 if (pipefds[0] != -1)
174 (void) close(pipefds[0]);
175 if (pipefds[1] == -1)
176 return;
177
178 #ifdef HAVE_SETSID
179 if (setsid() == -1)
180 err(1, "failed to detach from tty");
181 #endif
182
183 #ifndef WIN32
184 /*
185 * Hopefully we've written any pidfiles by now, if they had to be in
186 * the current directory...
187 *
188 * The daemons do re-open logs and so on, therefore this chdir()
189 * call needs to be optional for testing.
190 */
191 if (dir != NULL && chdir(dir) == -1)
192 err(1, "failed to chdir to /");
193 #endif
194
195 do {
196 bytes = write(pipefds[1], buf, sizeof(buf));
197 } while (bytes == -1 && errno == EINTR);
198 if (bytes == -1)
199 err(1, "failed to signal parent while detaching");
200 (void) close(pipefds[1]);
201 if (bytes != sizeof(buf))
202 errx(1, "failed to signal parent while detaching");
203
204 fd = open(_PATH_DEVNULL, O_RDWR, 0);
205 if (fd == -1)
206 err(1, "failed to open /dev/null");
207 /*
208 * Maybe we should check that our output got written, if redirected
209 * to a file. File utils normally do this.
210 */
211 (void) dup2(fd, STDOUT_FILENO);
212 (void) dup2(fd, STDERR_FILENO);
213 if (fd > 2)
214 (void) close(fd);
215 }
216