// Run the command specified by the argv array and kill it after timeout
// seconds.
static void SpawnCommand(char *const *argv, double timeout_secs) {
CHECK_CALL(global_child_pid = fork());
if (global_child_pid == 0) {
// In child.
CHECK_CALL(setsid());
ClearSignalMask();
// Force umask to include read and execute for everyone, to make
// output permissions predictable.
umask(022);
// Does not return unless something went wrong.
execvp(argv[0], argv);
err(EXIT_FAILURE, "execvp(\"%s\", ...)", argv[0]);
} else {
// In parent.
// Set up a signal handler which kills all subprocesses when the given
// signal is triggered.
HandleSignal(SIGALRM, OnSignal);
HandleSignal(SIGTERM, OnSignal);
HandleSignal(SIGINT, OnSignal);
SetTimeout(timeout_secs);
int status = WaitChild(global_child_pid, argv[0]);
// The child is done for, but may have grandchildren that we still have to
// kill.
kill(-global_child_pid, SIGKILL);
if (global_signal > 0) {
// Don't trust the exit code if we got a timeout or signal.
UnHandle(global_signal);
raise(global_signal);
} else if (WIFEXITED(status)) {
exit(WEXITSTATUS(status));
} else {
int sig = WTERMSIG(status);
UnHandle(sig);
raise(sig);
}
}
}
// Usage: process-wrapper
// <timeout_sec> <kill_delay_sec> <stdout file> <stderr file>
// [cmdline]
int main(int argc, char *argv[]) {
if (argc <= 5) {
DIE("Not enough cmd line arguments to process-wrapper");
}
// Parse the cmdline args to get the timeout and redirect files.
argv++;
double timeout;
if (sscanf(*argv++, "%lf", &timeout) != 1) {
DIE("timeout_sec is not a real number.");
}
if (sscanf(*argv++, "%lf", &global_kill_delay) != 1) {
DIE("kill_delay_sec is not a real number.");
}
char *stdout_path = *argv++;
char *stderr_path = *argv++;
if (strcmp(stdout_path, "-")) {
// Redirect stdout and stderr.
int fd_out = open(stdout_path, O_WRONLY|O_CREAT|O_TRUNC, 0666);
if (fd_out == -1) {
DIE("Could not open %s for stdout", stdout_path);
}
if (dup2(fd_out, STDOUT_FILENO) == -1) {
DIE("dup2 failed for stdout");
}
CHECK_CALL(close(fd_out));
}
if (strcmp(stderr_path, "-")) {
int fd_err = open(stderr_path, O_WRONLY|O_CREAT|O_TRUNC, 0666);
if (fd_err == -1) {
DIE("Could not open %s for stderr", stderr_path);
}
if (dup2(fd_err, STDERR_FILENO) == -1) {
DIE("dup2 failed for stderr");
}
CHECK_CALL(close(fd_err));
}
global_pid = fork();
if (global_pid < 0) {
DIE("Fork failed");
} else if (global_pid == 0) {
// In child.
if (setsid() == -1) {
DIE("Could not setsid from child");
}
ClearSignalMask();
// Force umask to include read and execute for everyone, to make
// output permissions predictable.
umask(022);
execvp(argv[0], argv); // Does not return.
DIE("execvpe %s failed", argv[0]);
} else {
// In parent.
InstallSignalHandler(SIGALRM);
InstallSignalHandler(SIGTERM);
InstallSignalHandler(SIGINT);
EnableAlarm(timeout);
int status = WaitChild(global_pid, argv[0]);
// The child is done, but may have grandchildren.
kill(-global_pid, SIGKILL);
if (global_signal > 0) {
// Don't trust the exit code if we got a timeout or signal.
UnHandle(global_signal);
raise(global_signal);
} else if (WIFEXITED(status)) {
exit(WEXITSTATUS(status));
} else {
int sig = WTERMSIG(status);
UnHandle(sig);
raise(sig);
}
}
}
