1 /***
2 This file is part of PulseAudio.
3
4 Copyright 2007 Lennart Poettering
5
6 PulseAudio is free software; you can redistribute it and/or modify
7 it under the terms of the GNU Lesser General Public License as
8 published by the Free Software Foundation; either version 2.1 of the
9 License, or (at your option) any later version.
10
11 PulseAudio is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with PulseAudio; if not, see <http://www.gnu.org/licenses/>.
18 ***/
19
20 #ifdef HAVE_CONFIG_H
21 #include <config.h>
22 #endif
23
24 #include <errno.h>
25 #include <stdio.h>
26 #include <sys/types.h>
27 #include <dirent.h>
28 #include <unistd.h>
29 #include <fcntl.h>
30 #include <signal.h>
31
32 #ifdef HAVE_SYS_PRCTL_H
33 #include <sys/prctl.h>
34 #endif
35 #ifdef HAVE_SYS_RESOURCE_H
36 #include <sys/resource.h>
37 #endif
38
39 #include <pulsecore/core-util.h>
40 #include <pulsecore/core-error.h>
41 #include <pulsecore/pipe.h>
42
43 #include "start-child.h"
44
pa_start_child_for_read(const char * name,const char * argv1,pid_t * pid)45 int pa_start_child_for_read(const char *name, const char *argv1, pid_t *pid) {
46 #ifdef HAVE_FORK
47 pid_t child;
48 int pipe_fds[2] = { -1, -1 };
49
50 if (pipe(pipe_fds) < 0) {
51 pa_log("pipe() failed: %s", pa_cstrerror(errno));
52 goto fail;
53 }
54
55 if ((child = fork()) == (pid_t) -1) {
56 pa_log("fork() failed: %s", pa_cstrerror(errno));
57 goto fail;
58
59 } else if (child != 0) {
60
61 /* Parent */
62 pa_assert_se(pa_close(pipe_fds[1]) == 0);
63
64 if (pid)
65 *pid = child;
66
67 return pipe_fds[0];
68 } else {
69 /* child */
70
71 pa_reset_personality();
72
73 pa_assert_se(pa_close(pipe_fds[0]) == 0);
74 pa_assert_se(dup2(pipe_fds[1], STDOUT_FILENO) == STDOUT_FILENO);
75
76 if (pipe_fds[1] != STDOUT_FILENO)
77 pa_assert_se(pa_close(pipe_fds[1]) == 0);
78
79 pa_close(STDIN_FILENO);
80 pa_assert_se(open("/dev/null", O_RDONLY) == STDIN_FILENO);
81
82 pa_close(STDERR_FILENO);
83 pa_assert_se(open("/dev/null", O_WRONLY) == STDERR_FILENO);
84
85 pa_close_all(-1);
86 pa_reset_sigs(-1);
87 pa_unblock_sigs(-1);
88 pa_reset_priority();
89 pa_unset_env_recorded();
90
91 /* Make sure our children are not influenced by the
92 * LD_BIND_NOW we set for ourselves. */
93 pa_unset_env("LD_BIND_NOW");
94
95 #ifdef PR_SET_PDEATHSIG
96 /* On Linux we can use PR_SET_PDEATHSIG to have the helper
97 process killed when the daemon dies abnormally. On non-Linux
98 machines the client will die as soon as it writes data to
99 stdout again (SIGPIPE) */
100
101 prctl(PR_SET_PDEATHSIG, SIGTERM, 0, 0, 0);
102 #endif
103
104 execl(name, name, argv1, NULL);
105 _exit(1);
106 }
107
108 fail:
109 pa_close_pipe(pipe_fds);
110 #endif /* HAVE_FORK */
111
112 return -1;
113 }
114