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/*
* 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 <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 std::string DescribeStatus(int status) {
if (WIFEXITED(status)) {
return android::base::StringPrintf("exited with status %d", WEXITSTATUS(status));
} else if (WIFSIGNALED(status)) {
return android::base::StringPrintf("killed by signal %d", WTERMSIG(status));
} else if (WIFSTOPPED(status)) {
return android::base::StringPrintf("stopped by signal %d", WSTOPSIG(status));
} else {
return "state changed";
}
}
static bool wait_for_one_process() {
int status;
pid_t pid = TEMP_FAILURE_RETRY(waitpid(-1, &status, WNOHANG));
if (pid == 0) {
return false;
} else if (pid == -1) {
ERROR("waitpid failed: %s\n", strerror(errno));
return false;
}
Service* svc = ServiceManager::GetInstance().FindServiceByPid(pid);
std::string name;
if (svc) {
name = android::base::StringPrintf("Service '%s' (pid %d)", svc->name().c_str(), pid);
} else {
name = android::base::StringPrintf("Untracked pid %d", pid);
}
NOTICE("%s %s\n", name.c_str(), DescribeStatus(status).c_str());
if (!svc) {
return true;
}
if (svc->Reap()) {
waiting_for_exec = false;
ServiceManager::GetInstance().RemoveService(*svc);
}
return true;
}
static void reap_any_outstanding_children() {
while (wait_for_one_process()) {
}
}
static void handle_signal() {
// Clear outstanding requests.
char buf[32];
read(signal_read_fd, buf, sizeof(buf));
reap_any_outstanding_children();
}
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);
reap_any_outstanding_children();
register_epoll_handler(signal_read_fd, handle_signal);
}
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