platform_system_core/init/signal_handler.cpp
Bertrand SIMONNET b7e03e82b8 init: Allows shutting down cleanly.
When ro.build.shutdown_timeout is set, init will send a SIGTERM signal to
all services on reboot. The normal shutdown process will continue once
all services have exited or after the shutdown timeout
(ro.build.shutdown_timeout).

If ro.build.shutdown_timeout is not set, we assume a 0s timeout.

Bug: 26216447
Test: manual: Ask to reboot. All services exit cleanly.

Change-Id: If921f6e8d87211e500ac9fa86f3e1eabe02d18cf
2016-01-08 11:12:15 -08:00

75 lines
2.1 KiB
C++

/*
* 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 <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <android-base/stringprintf.h>
#include <cutils/android_reboot.h>
#include <cutils/list.h>
#include <cutils/sockets.h>
#include "action.h"
#include "init.h"
#include "log.h"
#include "service.h"
#include "util.h"
static int signal_write_fd = -1;
static int signal_read_fd = -1;
static void handle_signal() {
// Clear outstanding requests.
char buf[32];
read(signal_read_fd, buf, sizeof(buf));
ServiceManager::GetInstance().ReapAnyOutstandingChildren();
}
static void SIGCHLD_handler(int) {
if (TEMP_FAILURE_RETRY(write(signal_write_fd, "1", 1)) == -1) {
ERROR("write(signal_write_fd) failed: %s\n", strerror(errno));
}
}
void signal_handler_init() {
// Create a signalling mechanism for SIGCHLD.
int s[2];
if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC, 0, s) == -1) {
ERROR("socketpair failed: %s\n", strerror(errno));
exit(1);
}
signal_write_fd = s[0];
signal_read_fd = s[1];
// Write to signal_write_fd if we catch SIGCHLD.
struct sigaction act;
memset(&act, 0, sizeof(act));
act.sa_handler = SIGCHLD_handler;
act.sa_flags = SA_NOCLDSTOP;
sigaction(SIGCHLD, &act, 0);
ServiceManager::GetInstance().ReapAnyOutstandingChildren();
register_epoll_handler(signal_read_fd, handle_signal);
}