Improve error reporting during daemonization (3802ceb6) · Commits · hpc / norns

src/urd.cpp

+40 −40

Original line number	Diff line number	Diff line
		@@ -84,40 +84,50 @@ pid_t urd::daemonize() {

		/* Fork off the parent process */
		if((pid = fork()) < 0) {
		LOGGER_ERROR("Failed to create child process: {}", strerror(errno));
		LOGGER_ERRNO("Failed to create child process");
		exit(EXIT_FAILURE);
		}

		/* Parent exits */
		/* Parent returns to caller */
		if(pid != 0) {
		return pid;
		}

		/* Obtain new process group */
		/* Become a session and process group leader with no controlling tty */
		if((sid = setsid()) < 0) {
		/* Log failure */
		LOGGER_ERROR("[daemonize] setsid failed.");
		perror("Setsid");
		LOGGER_ERRNO("Failed to disassociate controlling tty");
		exit(EXIT_FAILURE);
		}

		/* Close all descriptors */
		for(int i = getdtablesize() - 1; i >= 0; --i){
		close(i);
		if(close(i) != 0) {
		LOGGER_ERRNO("Failed to close descriptor");
		exit(EXIT_FAILURE);
		}
		}

		/* Handle standard IO */
		int fd = open("/dev/null", O_RDWR); /* open stdin */
		/* Handle standard IO: discard data to/from stdin, stdout and stderr */
		int dev_null;

		if((dev_null = open("/dev/null", O_RDWR)) == -1) {
		LOGGER_ERRNO("Failed to open \"/dev/null\"");
		exit(EXIT_FAILURE);
		}

		if(dup2(dev_null, STDIN_FILENO) == -1) {
		LOGGER_ERRNO("Failed to dup \"/dev/null\" onto stdin");
		exit(EXIT_FAILURE);
		}

		if(dup(fd) == -1) { /* stdout */
		LOGGER_ERROR("[daemonize] dup[1] failed.");
		perror("dup");
		if(dup2(dev_null, STDOUT_FILENO) == -1) {
		LOGGER_ERRNO("Failed to dup \"/dev/null\" onto stdout");
		exit(EXIT_FAILURE);
		}

		if(dup(fd) == -1) { /* stderr */
		LOGGER_ERROR("[daemonize] dup[2] failed.");
		perror("dup");
		if(dup2(dev_null, STDERR_FILENO) == -1) {
		LOGGER_ERRNO("Failed to dup \"/dev/null\" onto stderr");
		exit(EXIT_FAILURE);
		}

		@@ -127,8 +137,7 @@ pid_t urd::daemonize() {
		/* ensure the process does not keep a directory in use,
		* avoid relative paths beyond this point! */
		if(chdir("/") < 0) {
		LOGGER_ERROR("[daemonize] chdir failed.");
		perror("Chdir");
		LOGGER_ERRNO("Failed to change working directory to root directory");
		exit(EXIT_FAILURE);
		}

		@@ -136,40 +145,30 @@ pid_t urd::daemonize() {
		* First instance of the daemon will lock the file so that other
		* instances understand that an instance is already running.
		*/
		int pfd;

		int lfp;
		lfp = open(m_settings->m_daemon_pidfile.c_str(), O_RDWR\|O_CREAT, 0640);

		if(lfp < 0) {
		LOGGER_ERROR("[daemonize] can not open daemon lock file");
		perror("Can not open daemon lock file");
		if((pfd = open(m_settings->m_daemon_pidfile.c_str(), O_RDWR \| O_CREAT, 0640)) == -1) {
		LOGGER_ERRNO("Failed to create daemon lock file");
		exit(EXIT_FAILURE);
		}

		if(lockf(lfp, F_TLOCK, 0) < 0) {
		LOGGER_ERROR("[daemonize] another instance of this daemon already running");
		perror("Another instance of this daemon already running");
		if(lockf(pfd, F_TLOCK, 0) < 0) {
		LOGGER_ERRNO("Failed to acquire lock on pidfile");
		LOGGER_ERROR("Another instance of this daemon may already be running");
		exit(EXIT_FAILURE);
		}

		/* record pid in lockfile */
		char str[10];
		size_t err_snprintf;
		err_snprintf = snprintf(str, sizeof(str), "%d\n", getpid());

		if(err_snprintf >= sizeof(str)) {
		LOGGER_ERROR("[daemonize] snprintf failed");
		}
		std::string pidstr(std::to_string(getpid()));

		size_t err_write;
		err_write = write(lfp, str, strnlen(str, sizeof(str)));

		if(err_write != strnlen(str, sizeof(str))) {
		LOGGER_ERROR("[daemonize] write failed");
		if(write(pfd, pidstr.c_str(), pidstr.length()) !=
		static_cast<ssize_t>(pidstr.length())) {
		LOGGER_ERRNO("Failed to write pidfile");
		exit(EXIT_FAILURE);
		}

		close(lfp);
		close(fd);
		close(pfd);
		close(dev_null);

		/* Manage signals */
		signal(SIGCHLD, SIG_IGN); /* ignore child */
		@@ -179,6 +178,7 @@ pid_t urd::daemonize() {
		// signal(SIGHUP, signal_handler); /* catch hangup signal */
		// signal(SIGTERM, signal_handler); /* catch kill signal */

		return 0;
		}

		urd_error urd::validate_iotask_args(iotask_type type,