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#include "linux-run.h"
#include <functional>
#include <stdexcept>
#include <string>
#include <vector>
#include <errno.h>
#include <fcntl.h>
#include <poll.h>
#include <signal.h>
#include <string.h> // for strerror_r (GNU extension)
#include <sys/signalfd.h>
#include <sys/wait.h>
#include <unistd.h>
namespace linux_run {
static std::string get_errno_message() {
char buffer[100];
strerror_r(errno, buffer, 100);
return std::string(buffer);
}
static std::string get_errno_message(int custom_errno) {
char buffer[100];
strerror_r(custom_errno, buffer, 100);
return std::string(buffer);
}
static void create_signal_fd(int *pfd) {
sigset_t sigset;
sigemptyset(&sigset);
sigaddset(&sigset, SIGCHLD);
if (sigprocmask(SIG_BLOCK, &sigset, nullptr) == -1) {
throw std::runtime_error("Failed to block SIGCHLD. Reason: " +
get_errno_message());
}
sigemptyset(&sigset);
sigaddset(&sigset, SIGCHLD);
int fd = signalfd(-1, &sigset, 0);
if (fd == -1) {
throw std::runtime_error("Failed to create SIGCHLD fd. Reason: " +
get_errno_message());
}
*pfd = fd;
}
static void destroy_signal_fd(int fd) {
if (close(fd) == -1) {
throw std::runtime_error("Failed to close SIGCHLD fd. Reason: " +
get_errno_message());
}
sigset_t sigset;
sigemptyset(&sigset);
sigaddset(&sigset, SIGCHLD);
if (sigprocmask(SIG_UNBLOCK, &sigset, nullptr) == -1) {
throw std::runtime_error("Failed to unblock SIGCHLD. Reason: " +
get_errno_message());
}
}
static char **
convert_string_vector_to_argv(const std::string &program,
const std::vector<std::string> &arguments) {
char **argv;
argv = new char *[arguments.size() + 2];
argv[0] = new char[program.size() + 1];
strcpy(argv[0], program.c_str());
for (int i = 0; i < arguments.size(); i++) {
const auto &argument = arguments[i];
argv[i + 1] = new char[argument.size() + 1];
strcpy(argv[i + 1], argument.c_str());
}
argv[arguments.size() + 1] = nullptr;
return argv;
}
static void redirect_file(int old_file_descriptor, const std::string &path,
int open_file_flags) {
if (path.empty())
return;
int file_descriptor = open(path.c_str(), open_file_flags);
if (file_descriptor == -1)
throw std::runtime_error(
"Failed to open " + path +
" for redirection. Reason: " + get_errno_message());
int dup_r = dup2(file_descriptor, old_file_descriptor);
if (dup_r == -1)
throw std::runtime_error(
"Failed to dup file descriptor for redirection. Reason: " +
get_errno_message());
int close_r = close(file_descriptor);
if (close_r == -1)
throw std::runtime_error(
"Failed to close old file descriptor for redirection. Reason: " +
get_errno_message());
}
void run(const std::string &program, std::vector<std::string> arguments,
RunOptions options) {
int sigchld_fd;
create_signal_fd(&sigchld_fd);
pid_t pid = fork();
if (pid == 0) {
destroy_signal_fd(sigchld_fd);
redirect_file(STDIN_FILENO, options.stdin_file_path, O_RDONLY);
redirect_file(STDOUT_FILENO, options.stdout_file_path,
O_WRONLY | O_CREAT | O_TRUNC);
auto argv = convert_string_vector_to_argv(program, arguments);
int r = execvp(program.c_str(), argv);
throw std::runtime_error("Failed to exec: " + get_errno_message());
}
if (pid == -1) {
throw std::runtime_error("Failed to fork: " + get_errno_message());
}
struct pollfd sigchld_poll;
sigchld_poll.fd = sigchld_fd;
sigchld_poll.events = POLLIN;
sigchld_poll.revents = 0;
int timeout_value =
options.timeout_in_second > 0 ? options.timeout_in_second * 1000 : -1;
while (true) {
int poll_return = poll(&sigchld_poll, 1, timeout_value);
if (poll_return == 0) {
kill(pid, SIGKILL);
if (options.stop_reason) {
*options.stop_reason = StopReason::Killed;
}
if (options.before_reap_callback) {
options.before_reap_callback(pid);
}
// Reap child process.
if (waitpid(pid, nullptr, 0) == -1) {
throw std::runtime_error("Failed to reap child process. Reason: " +
get_errno_message());
}
throw TimeoutError("Timeout to run command.");
} else if (poll_return == -1) {
if (errno == EINTR) {
continue;
} else {
throw std::runtime_error("Failed to poll. Reason: " +
get_errno_message());
}
} else if (poll_return == 1) {
break;
} else {
throw std::runtime_error("Poll returns a wired value.");
}
}
signalfd_siginfo sig_info;
if (sigchld_poll.revents & POLLIN) {
size_t read_size = sizeof(signalfd_siginfo);
int read_return = read(sigchld_fd, &sig_info, read_size);
if (read_return == -1) {
throw std::runtime_error("Failed to read signal fd. Reason: " +
get_errno_message());
} else if (read_return != read_size) {
throw std::runtime_error("Failed to read signal fd because the return "
"byte count does not match request.");
}
} else {
throw std::runtime_error("SIGCHLD fd is not readable after poll.");
}
switch (sig_info.ssi_code) {
case CLD_EXITED: {
if (options.stop_reason) {
*options.stop_reason = StopReason::Exited;
}
int exit_code = sig_info.ssi_status;
if (options.exit_code) {
*options.exit_code = exit_code;
}
if (options.check_exit_code) {
if (exit_code != 0) {
throw ExitCodeError("Command exit with nonzero value.");
}
}
} break;
case CLD_KILLED: {
if (options.stop_reason) {
*options.stop_reason = StopReason::Killed;
}
} break;
default:
throw std::runtime_error("Unsupported sig_info code.");
}
if (options.before_reap_callback) {
options.before_reap_callback(pid);
}
// Reap child.
if (waitpid(pid, nullptr, 0) == -1) {
throw std::runtime_error("Failed to reap child process. Reason: " +
get_errno_message());
}
}
} // namespace linux_run
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