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1 // Copyright (c) 2013 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #include "sandbox/linux/services/init_process_reaper.h" | |
6 | |
7 #include <signal.h> | |
8 #include <string.h> | |
9 #include <sys/socket.h> | |
10 #include <sys/types.h> | |
11 #include <sys/wait.h> | |
12 #include <unistd.h> | |
13 | |
14 #include "base/callback.h" | |
15 #include "base/logging.h" | |
16 #include "base/posix/eintr_wrapper.h" | |
17 | |
18 namespace sandbox { | |
19 | |
20 namespace { | |
21 | |
22 void DoNothingSignalHandler(int signal) {} | |
23 | |
24 } // namespace | |
25 | |
26 bool CreateInitProcessReaper(base::Closure* post_fork_parent_callback) { | |
27 int sync_fds[2]; | |
28 // We want to use send, so we can't use a pipe | |
29 if (socketpair(AF_UNIX, SOCK_STREAM, 0, sync_fds)) { | |
30 LOG(ERROR) << "Failed to create socketpair"; | |
Jorge Lucangeli Obes
2013/11/27 02:31:53
PLOG?
jln (very slow on Chromium)
2013/11/27 02:37:14
Done.
| |
31 return false; | |
32 } | |
33 // We use normal fork, not the ForkDelegate in this case since we are not a | |
34 // true Zygote yet. | |
35 pid_t child_pid = fork(); | |
36 if (child_pid == -1) { | |
37 int close_ret; | |
38 close_ret = HANDLE_EINTR(close(sync_fds[0])); | |
39 DPCHECK(!close_ret); | |
40 close_ret = HANDLE_EINTR(close(sync_fds[1])); | |
41 DPCHECK(!close_ret); | |
42 return false; | |
43 } | |
44 if (child_pid) { | |
45 // We are the parent, assuming the role of an init process. | |
46 // The disposition for SIGCHLD cannot be SIG_IGN or wait() will only return | |
47 // once all of our childs are dead. Since we're init we need to reap childs | |
48 // as they come. | |
49 struct sigaction action; | |
50 memset(&action, 0, sizeof(action)); | |
51 action.sa_handler = &DoNothingSignalHandler; | |
52 CHECK(sigaction(SIGCHLD, &action, NULL) == 0); | |
53 | |
54 int close_ret; | |
55 close_ret = HANDLE_EINTR(close(sync_fds[0])); | |
56 DPCHECK(!close_ret); | |
57 close_ret = shutdown(sync_fds[1], SHUT_RD); | |
58 DPCHECK(!close_ret); | |
59 if (post_fork_parent_callback) | |
60 post_fork_parent_callback->Run(); | |
61 // Tell the child to continue | |
62 CHECK(HANDLE_EINTR(send(sync_fds[1], "C", 1, MSG_NOSIGNAL)) == 1); | |
63 close_ret = HANDLE_EINTR(close(sync_fds[1])); | |
64 DPCHECK(!close_ret); | |
65 | |
66 for (;;) { | |
67 // Loop until we have reaped our one natural child | |
68 siginfo_t reaped_child_info; | |
69 int wait_ret = | |
70 HANDLE_EINTR(waitid(P_ALL, 0, &reaped_child_info, WEXITED)); | |
71 if (wait_ret) | |
72 _exit(1); | |
73 if (reaped_child_info.si_pid == child_pid) { | |
74 int exit_code = 0; | |
75 // We're done waiting | |
76 if (reaped_child_info.si_code == CLD_EXITED) { | |
77 exit_code = reaped_child_info.si_status; | |
78 } | |
79 // Exit with the same exit code as our parent. This is most likely | |
80 // useless. _exit with 0 if we got signaled. | |
81 _exit(exit_code); | |
82 } | |
83 } | |
84 } else { | |
85 // The child needs to wait for the parent to close kZygoteIdFd to avoid a | |
86 // race condition | |
87 int close_ret; | |
88 close_ret = HANDLE_EINTR(close(sync_fds[1])); | |
89 DPCHECK(!close_ret); | |
90 close_ret = shutdown(sync_fds[0], SHUT_WR); | |
91 DPCHECK(!close_ret); | |
92 char should_continue; | |
93 int read_ret = HANDLE_EINTR(read(sync_fds[0], &should_continue, 1)); | |
94 close_ret = HANDLE_EINTR(close(sync_fds[0])); | |
95 DPCHECK(!close_ret); | |
96 if (read_ret == 1) | |
97 return true; | |
98 else | |
99 return false; | |
100 } | |
101 } | |
102 | |
103 } // namespace sandbox. | |
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