1 files changed, 159 insertions, 0 deletions
diff --git a/init/signal_handler.c b/init/signal_handler.c
new file mode 100644
index 0000000..3e5d136
--- /dev/null
+++ b/init/signal_handler.c
@@ -0,0 +1,159 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+#include <errno.h>
+#include <signal.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+#include <cutils/sockets.h>
+#include <sys/reboot.h>
+
+#include "init.h"
+#include "list.h"
+#include "util.h"
+#include "log.h"
+
+static int signal_fd = -1;
+static int signal_recv_fd = -1;
+
+static void sigchld_handler(int s)
+{
+    write(signal_fd, &s, 1);
+}
+
+#define CRITICAL_CRASH_THRESHOLD    4       /* if we crash >4 times ... */
+#define CRITICAL_CRASH_WINDOW       (4*60)  /* ... in 4 minutes, goto recovery*/
+
+static int wait_for_one_process(int block)
+{
+    pid_t pid;
+    int status;
+    struct service *svc;
+    struct socketinfo *si;
+    time_t now;
+    struct listnode *node;
+    struct command *cmd;
+
+    while ( (pid = waitpid(-1, &status, block ? 0 : WNOHANG)) == -1 && errno == EINTR );
+    if (pid <= 0) return -1;
+    INFO("waitpid returned pid %d, status = %08x\n", pid, status);
+
+    svc = service_find_by_pid(pid);
+    if (!svc) {
+        ERROR("untracked pid %d exited\n", pid);
+        return 0;
+    }
+
+    NOTICE("process '%s', pid %d exited\n", svc->name, pid);
+
+    if (!(svc->flags & SVC_ONESHOT)) {
+        kill(-pid, SIGKILL);
+        NOTICE("process '%s' killing any children in process group\n", svc->name);
+    }
+
+    /* remove any sockets we may have created */
+    for (si = svc->sockets; si; si = si->next) {
+        char tmp[128];
+        snprintf(tmp, sizeof(tmp), ANDROID_SOCKET_DIR"/%s", si->name);
+        unlink(tmp);
+    }
+
+    svc->pid = 0;
+    svc->flags &= (~SVC_RUNNING);
+
+        /* oneshot processes go into the disabled state on exit */
+    if (svc->flags & SVC_ONESHOT) {
+        svc->flags |= SVC_DISABLED;
+    }
+
+        /* disabled processes do not get restarted automatically */
+    if (svc->flags & SVC_DISABLED) {
+        notify_service_state(svc->name, "stopped");
+        return 0;
+    }
+
+    now = gettime();
+    if (svc->flags & SVC_CRITICAL) {
+        if (svc->time_crashed + CRITICAL_CRASH_WINDOW >= now) {
+            if (++svc->nr_crashed > CRITICAL_CRASH_THRESHOLD) {
+                ERROR("critical process '%s' exited %d times in %d minutes; "
+                      "rebooting into recovery mode\n", svc->name,
+                      CRITICAL_CRASH_THRESHOLD, CRITICAL_CRASH_WINDOW / 60);
+                sync();
+                __reboot(LINUX_REBOOT_MAGIC1, LINUX_REBOOT_MAGIC2,
+                         LINUX_REBOOT_CMD_RESTART2, "recovery");
+                return 0;
+            }
+        } else {
+            svc->time_crashed = now;
+            svc->nr_crashed = 1;
+        }
+    }
+
+    svc->flags |= SVC_RESTARTING;
+
+    /* Execute all onrestart commands for this service. */
+    list_for_each(node, &svc->onrestart.commands) {
+        cmd = node_to_item(node, struct command, clist);
+        cmd->func(cmd->nargs, cmd->args);
+    }
+    notify_service_state(svc->name, "restarting");
+    return 0;
+}
+
+void handle_signal(void)
+{
+    char tmp[32];
+
+    /* we got a SIGCHLD - reap and restart as needed */
+    read(signal_recv_fd, tmp, sizeof(tmp));
+    while (!wait_for_one_process(0))
+        ;
+}
+
+void signal_init(void)
+{
+    int s[2];
+
+    struct sigaction act;
+
+    act.sa_handler = sigchld_handler;
+    act.sa_flags = SA_NOCLDSTOP;
+    act.sa_mask = 0;
+    act.sa_restorer = NULL;
+    sigaction(SIGCHLD, &act, 0);
+
+    /* create a signalling mechanism for the sigchld handler */
+    if (socketpair(AF_UNIX, SOCK_STREAM, 0, s) == 0) {
+        signal_fd = s[0];
+        signal_recv_fd = s[1];
+        fcntl(s[0], F_SETFD, FD_CLOEXEC);
+        fcntl(s[0], F_SETFL, O_NONBLOCK);
+        fcntl(s[1], F_SETFD, FD_CLOEXEC);
+        fcntl(s[1], F_SETFL, O_NONBLOCK);
+    }
+
+    handle_signal();
+}
+
+int get_signal_fd()
+{
+    return signal_recv_fd;
+}