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/*
* Copyright (C) 2015 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 "workload.h"
#include <errno.h>
#include <fcntl.h>
#include <sys/wait.h>
#include <unistd.h>
#include <base/logging.h>
std::unique_ptr<Workload> Workload::CreateWorkload(const std::vector<std::string>& args) {
std::unique_ptr<Workload> workload(new Workload(args));
if (workload != nullptr && workload->CreateNewProcess()) {
return workload;
}
return nullptr;
}
static void ChildProcessFn(std::vector<std::string>& args, int start_signal_fd, int exec_child_fd);
bool Workload::CreateNewProcess() {
CHECK_EQ(work_state_, NotYetCreateNewProcess);
int start_signal_pipe[2];
if (pipe2(start_signal_pipe, O_CLOEXEC) != 0) {
PLOG(ERROR) << "pipe2() failed";
return false;
}
int exec_child_pipe[2];
if (pipe2(exec_child_pipe, O_CLOEXEC) != 0) {
PLOG(ERROR) << "pipe2() failed";
close(start_signal_pipe[0]);
close(start_signal_pipe[1]);
return false;
}
pid_t pid = fork();
if (pid == -1) {
PLOG(ERROR) << "fork() failed";
close(start_signal_pipe[0]);
close(start_signal_pipe[1]);
close(exec_child_pipe[0]);
close(exec_child_pipe[1]);
return false;
} else if (pid == 0) {
// In child process.
close(start_signal_pipe[1]);
close(exec_child_pipe[0]);
ChildProcessFn(args_, start_signal_pipe[0], exec_child_pipe[1]);
}
// In parent process.
close(start_signal_pipe[0]);
close(exec_child_pipe[1]);
start_signal_fd_ = start_signal_pipe[1];
exec_child_fd_ = exec_child_pipe[0];
work_pid_ = pid;
work_state_ = NotYetStartNewProcess;
return true;
}
static void ChildProcessFn(std::vector<std::string>& args, int start_signal_fd, int exec_child_fd) {
std::vector<char*> argv(args.size() + 1);
for (size_t i = 0; i < args.size(); ++i) {
argv[i] = &args[i][0];
}
argv[args.size()] = nullptr;
char start_signal = 0;
ssize_t nread = TEMP_FAILURE_RETRY(read(start_signal_fd, &start_signal, 1));
if (nread == 1 && start_signal == 1) {
close(start_signal_fd);
execvp(argv[0], argv.data());
// If execvp() succeed, we will not arrive here. But if it failed, we need to
// report the failure to the parent process by writing 1 to exec_child_fd.
int saved_errno = errno;
char exec_child_failed = 1;
TEMP_FAILURE_RETRY(write(exec_child_fd, &exec_child_failed, 1));
close(exec_child_fd);
errno = saved_errno;
PLOG(ERROR) << "execvp(" << argv[0] << ") failed";
} else {
PLOG(DEBUG) << "child process failed to receive start_signal, nread = " << nread;
}
exit(1);
}
bool Workload::Start() {
CHECK_EQ(work_state_, NotYetStartNewProcess);
char start_signal = 1;
ssize_t nwrite = TEMP_FAILURE_RETRY(write(start_signal_fd_, &start_signal, 1));
if (nwrite != 1) {
PLOG(ERROR) << "write start signal failed";
return false;
}
char exec_child_failed;
ssize_t nread = TEMP_FAILURE_RETRY(read(exec_child_fd_, &exec_child_failed, 1));
if (nread != 0) {
LOG(ERROR) << "exec child failed";
return false;
}
work_state_ = Started;
return true;
}
bool Workload::IsFinished() {
if (work_state_ == Started) {
WaitChildProcess(true);
}
return work_state_ == Finished;
}
void Workload::WaitFinish() {
CHECK(work_state_ == Started || work_state_ == Finished);
if (work_state_ == Started) {
WaitChildProcess(false);
}
}
void Workload::WaitChildProcess(bool no_hang) {
int status;
pid_t result = TEMP_FAILURE_RETRY(waitpid(work_pid_, &status, (no_hang ? WNOHANG : 0)));
if (result == work_pid_) {
work_state_ = Finished;
if (WIFSIGNALED(status)) {
LOG(ERROR) << "work process was terminated by signal " << strsignal(WTERMSIG(status));
} else if (WIFEXITED(status) && WEXITSTATUS(status) != 0) {
LOG(ERROR) << "work process exited with exit code " << WEXITSTATUS(status);
}
} else if (result == -1) {
PLOG(FATAL) << "waitpid() failed";
}
}
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