dc97e3e091
An earlier such change was reverted in commit e242a97db5.
Bug: 70487538
Test: ensure that angler can boot
Merged-In: Id5f57fce1c9b817a2650e0c848143d8a0d286bf0
Change-Id: Id5f57fce1c9b817a2650e0c848143d8a0d286bf0
146 lines
4.4 KiB
C++
146 lines
4.4 KiB
C++
/*
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* Copyright (C) 2010 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "sigchld_handler.h"
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#include <signal.h>
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#include <string.h>
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#include <sys/socket.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <unistd.h>
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#include <android-base/chrono_utils.h>
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#include <android-base/logging.h>
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#include <android-base/scopeguard.h>
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#include <android-base/stringprintf.h>
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#include "init.h"
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#include "property_service.h"
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#include "service.h"
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using android::base::StringPrintf;
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using android::base::boot_clock;
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using android::base::make_scope_guard;
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namespace android {
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namespace init {
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static int signal_write_fd = -1;
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static int signal_read_fd = -1;
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static bool ReapOneProcess() {
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siginfo_t siginfo = {};
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// This returns a zombie pid or informs us that there are no zombies left to be reaped.
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// It does NOT reap the pid; that is done below.
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if (TEMP_FAILURE_RETRY(waitid(P_ALL, 0, &siginfo, WEXITED | WNOHANG | WNOWAIT)) != 0) {
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PLOG(ERROR) << "waitid failed";
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return false;
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}
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auto pid = siginfo.si_pid;
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if (pid == 0) return false;
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// At this point we know we have a zombie pid, so we use this scopeguard to reap the pid
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// whenever the function returns from this point forward.
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// We do NOT want to reap the zombie earlier as in Service::Reap(), we kill(-pid, ...) and we
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// want the pid to remain valid throughout that (and potentially future) usages.
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auto reaper = make_scope_guard([pid] { TEMP_FAILURE_RETRY(waitpid(pid, nullptr, WNOHANG)); });
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std::string name;
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std::string wait_string;
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Service* service = nullptr;
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if (PropertyChildReap(pid)) {
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name = "Async property child";
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} else if (SubcontextChildReap(pid)) {
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name = "Subcontext";
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} else {
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service = ServiceList::GetInstance().FindService(pid, &Service::pid);
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if (service) {
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name = StringPrintf("Service '%s' (pid %d)", service->name().c_str(), pid);
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if (service->flags() & SVC_EXEC) {
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auto exec_duration = boot_clock::now() - service->time_started();
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auto exec_duration_ms =
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std::chrono::duration_cast<std::chrono::milliseconds>(exec_duration).count();
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wait_string = StringPrintf(" waiting took %f seconds", exec_duration_ms / 1000.0f);
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}
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} else {
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name = StringPrintf("Untracked pid %d", pid);
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}
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}
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if (siginfo.si_code == CLD_EXITED) {
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LOG(INFO) << name << " exited with status " << siginfo.si_status << wait_string;
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} else {
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LOG(INFO) << name << " received signal " << siginfo.si_status << wait_string;
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}
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if (!service) return true;
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service->Reap(siginfo);
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if (service->flags() & SVC_TEMPORARY) {
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ServiceList::GetInstance().RemoveService(*service);
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}
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return true;
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}
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static void handle_signal() {
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// Clear outstanding requests.
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char buf[32];
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read(signal_read_fd, buf, sizeof(buf));
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ReapAnyOutstandingChildren();
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}
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static void SIGCHLD_handler(int) {
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if (TEMP_FAILURE_RETRY(write(signal_write_fd, "1", 1)) == -1) {
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PLOG(ERROR) << "write(signal_write_fd) failed";
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}
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}
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void ReapAnyOutstandingChildren() {
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while (ReapOneProcess()) {
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}
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}
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void sigchld_handler_init() {
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// Create a signalling mechanism for SIGCHLD.
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int s[2];
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if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC, 0, s) == -1) {
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PLOG(FATAL) << "socketpair failed in sigchld_handler_init";
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}
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signal_write_fd = s[0];
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signal_read_fd = s[1];
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// Write to signal_write_fd if we catch SIGCHLD.
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struct sigaction act;
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memset(&act, 0, sizeof(act));
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act.sa_handler = SIGCHLD_handler;
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act.sa_flags = SA_NOCLDSTOP;
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sigaction(SIGCHLD, &act, 0);
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ReapAnyOutstandingChildren();
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register_epoll_handler(signal_read_fd, handle_signal);
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}
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} // namespace init
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} // namespace android
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