1 /*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include <stdio.h>
18 #include <errno.h>
19 #include <signal.h>
20 #include <unistd.h>
21 #include <fcntl.h>
22 #include <sys/types.h>
23 #include <sys/socket.h>
24 #include <sys/wait.h>
25 #include <cutils/sockets.h>
26 #include <sys/reboot.h>
27
28 #include "init.h"
29 #include "list.h"
30 #include "util.h"
31 #include "log.h"
32
33 static int signal_fd = -1;
34 static int signal_recv_fd = -1;
35
sigchld_handler(int s)36 static void sigchld_handler(int s)
37 {
38 write(signal_fd, &s, 1);
39 }
40
41 #define CRITICAL_CRASH_THRESHOLD 4 /* if we crash >4 times ... */
42 #define CRITICAL_CRASH_WINDOW (4*60) /* ... in 4 minutes, goto recovery*/
43
wait_for_one_process(int block)44 static int wait_for_one_process(int block)
45 {
46 pid_t pid;
47 int status;
48 struct service *svc;
49 struct socketinfo *si;
50 time_t now;
51 struct listnode *node;
52 struct command *cmd;
53
54 while ( (pid = waitpid(-1, &status, block ? 0 : WNOHANG)) == -1 && errno == EINTR );
55 if (pid <= 0) return -1;
56 INFO("waitpid returned pid %d, status = %08x\n", pid, status);
57
58 svc = service_find_by_pid(pid);
59 if (!svc) {
60 ERROR("untracked pid %d exited\n", pid);
61 return 0;
62 }
63
64 NOTICE("process '%s', pid %d exited\n", svc->name, pid);
65
66 if (!(svc->flags & SVC_ONESHOT)) {
67 kill(-pid, SIGKILL);
68 NOTICE("process '%s' killing any children in process group\n", svc->name);
69 }
70
71 /* remove any sockets we may have created */
72 for (si = svc->sockets; si; si = si->next) {
73 char tmp[128];
74 snprintf(tmp, sizeof(tmp), ANDROID_SOCKET_DIR"/%s", si->name);
75 unlink(tmp);
76 }
77
78 svc->pid = 0;
79 svc->flags &= (~SVC_RUNNING);
80
81 /* oneshot processes go into the disabled state on exit */
82 if (svc->flags & SVC_ONESHOT) {
83 svc->flags |= SVC_DISABLED;
84 }
85
86 /* disabled processes do not get restarted automatically */
87 if (svc->flags & SVC_DISABLED) {
88 notify_service_state(svc->name, "stopped");
89 return 0;
90 }
91
92 now = gettime();
93 if (svc->flags & SVC_CRITICAL) {
94 if (svc->time_crashed + CRITICAL_CRASH_WINDOW >= now) {
95 if (++svc->nr_crashed > CRITICAL_CRASH_THRESHOLD) {
96 ERROR("critical process '%s' exited %d times in %d minutes; "
97 "rebooting into recovery mode\n", svc->name,
98 CRITICAL_CRASH_THRESHOLD, CRITICAL_CRASH_WINDOW / 60);
99 sync();
100 __reboot(LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2,
101 LINUX_REBOOT_CMD_RESTART2, "recovery");
102 return 0;
103 }
104 } else {
105 svc->time_crashed = now;
106 svc->nr_crashed = 1;
107 }
108 }
109
110 svc->flags |= SVC_RESTARTING;
111
112 /* Execute all onrestart commands for this service. */
113 list_for_each(node, &svc->onrestart.commands) {
114 cmd = node_to_item(node, struct command, clist);
115 cmd->func(cmd->nargs, cmd->args);
116 }
117 notify_service_state(svc->name, "restarting");
118 return 0;
119 }
120
handle_signal(void)121 void handle_signal(void)
122 {
123 char tmp[32];
124
125 /* we got a SIGCHLD - reap and restart as needed */
126 read(signal_recv_fd, tmp, sizeof(tmp));
127 while (!wait_for_one_process(0))
128 ;
129 }
130
signal_init(void)131 void signal_init(void)
132 {
133 int s[2];
134
135 struct sigaction act;
136
137 act.sa_handler = sigchld_handler;
138 act.sa_flags = SA_NOCLDSTOP;
139 act.sa_mask = 0;
140 act.sa_restorer = NULL;
141 sigaction(SIGCHLD, &act, 0);
142
143 /* create a signalling mechanism for the sigchld handler */
144 if (socketpair(AF_UNIX, SOCK_STREAM, 0, s) == 0) {
145 signal_fd = s[0];
146 signal_recv_fd = s[1];
147 fcntl(s[0], F_SETFD, FD_CLOEXEC);
148 fcntl(s[0], F_SETFL, O_NONBLOCK);
149 fcntl(s[1], F_SETFD, FD_CLOEXEC);
150 fcntl(s[1], F_SETFL, O_NONBLOCK);
151 }
152
153 handle_signal();
154 }
155
get_signal_fd()156 int get_signal_fd()
157 {
158 return signal_recv_fd;
159 }
160