/*
* This function forks a child process and drops the realtime
* scheduler for the child process.
*/
pid_t ctdb_fork(struct ctdb_context *ctdb)
{
pid_t pid;
pid = fork();
if (pid == -1) {
return -1;
}
if (pid == 0) {
ctdb_set_child_info(ctdb, NULL);
/* Close the Unix Domain socket and the TCP socket.
* This ensures that none of the child processes will
* look like the main daemon when it is not running.
* tevent needs to be stopped before closing sockets.
*/
if (ctdb->ev != NULL) {
talloc_free(ctdb->ev);
ctdb->ev = NULL;
}
if (ctdb->daemon.sd != -1) {
close(ctdb->daemon.sd);
ctdb->daemon.sd = -1;
}
if (ctdb->methods != NULL) {
ctdb->methods->shutdown(ctdb);
}
/* The child does not need to be realtime */
if (ctdb->do_setsched) {
reset_scheduler();
}
ctdb->can_send_controls = false;
return 0;
}
ctdb_track_child(ctdb, pid);
return pid;
}
int main(int argc, char *argv[])
{
int log_fd, write_fd;
pid_t pid;
int status, output, ret;
progname = argv[0];
if (argc < 5) {
usage();
exit(1);
}
reset_scheduler();
log_fd = atoi(argv[1]);
write_fd = atoi(argv[2]);
set_close_on_exec(write_fd);
close(STDOUT_FILENO);
close(STDERR_FILENO);
dup2(log_fd, STDOUT_FILENO);
dup2(log_fd, STDERR_FILENO);
close(log_fd);
if (setpgid(0, 0) != 0) {
fprintf(stderr, "Failed to create process group for event script - %s\n",
strerror(errno));
exit(1);
}
signal(SIGTERM, sigterm);
pid = fork();
if (pid < 0) {
int save_errno = errno;
fprintf(stderr, "Failed to fork - %s\n", strerror(errno));
sys_write(write_fd, &save_errno, sizeof(save_errno));
exit(1);
}
if (pid == 0) {
ret = check_executable(argv[3]);
if (ret != 0) {
_exit(ret);
}
ret = execv(argv[3], &argv[3]);
if (ret != 0) {
int save_errno = errno;
fprintf(stderr, "Error executing '%s' - %s\n",
argv[3], strerror(save_errno));
}
/* This should never happen */
_exit(ENOEXEC);
}
ret = waitpid(pid, &status, 0);
if (ret == -1) {
output = -errno;
fprintf(stderr, "waitpid() failed - %s\n", strerror(errno));
sys_write(write_fd, &output, sizeof(output));
exit(1);
}
if (WIFEXITED(status)) {
output = WEXITSTATUS(status);
/* Only errors should be returned as -ve values */
if (output == ENOENT || output == ENOEXEC) {
output = -output;
}
sys_write(write_fd, &output, sizeof(output));
exit(0);
}
if (WIFSIGNALED(status)) {
output = -EINTR;
fprintf(stderr, "Process terminated with signal - %d\n",
WTERMSIG(status));
sys_write(write_fd, &output, sizeof(output));
exit(0);
}
fprintf(stderr, "waitpid() status=%d\n", status);
exit(1);
}
static void reset_priority(void)
{
if (realtime) {
reset_scheduler();
}
}