1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
52 static int acquire_lock(union lock_subject *subj, int flags, int silent);
63 static sig_atomic_t child = -1;
64 static int lockfd = -1;
82 	if (strncmp(name, FDLOCK_PREFIX, sizeof(FDLOCK_PREFIX) - 1) != 0)  in fdlock_implied()
86 	name += sizeof(FDLOCK_PREFIX) - 1;  in fdlock_implied()
111 	bool silent, writepid;  in main()  local
113 	silent = writepid = false;  in main()
115 	waitsec = -1;	/* Infinite. */  in main()
116 	while ((ch = getopt(argc, argv, "knpsTt:w")) != -1) {  in main()
125 			silent = true;  in main()
148 	argc -= optind;  in main()
156 	argc--;  in main()
164 		subj.subj_fd = -1;  in main()
205 	 * If the "-k" option is not given, then we must not block when  in main()
221 	 * When the "-k" option is used, the unlink race no longer  in main()
226 	lockfd = acquire_lock(&subj, flags | O_NONBLOCK, silent);  in main()
227 	while (lockfd == -1 && !timed_out && waitsec != 0) {  in main()
229 			lockfd = acquire_lock(&subj, flags, silent);  in main()
233 			    silent);  in main()
241 	if (lockfd == -1) {		/* We failed to acquire the lock. */  in main()
242 		if (silent)  in main()
255 	if (atexit(cleanup) == -1)  in main()
261 	 * an invalid pid (i.e., waited-on).  If our setup between here and the  in main()
277 	if ((child = fork()) == -1)  in main()
315  * on success, or -1 on failure.
318 acquire_lock(union lock_subject *subj, int flags, int silent)  in acquire_lock()  argument
323 		assert(subj->subj_fd >= 0 && subj->subj_fd <= INT_MAX);  in acquire_lock()
324 		fd = (int)subj->subj_fd;  in acquire_lock()
326 		if (flock(fd, LOCK_EX | LOCK_NB) == -1) {  in acquire_lock()
328 				return (-1);  in acquire_lock()
331 	} else if ((fd = open(subj->subj_name, O_EXLOCK|flags, 0666)) == -1) {  in acquire_lock()
333 			return (-1);  in acquire_lock()
335 			if (!silent)  in acquire_lock()
336 				warn("%s", subj->subj_name);  in acquire_lock()
339 		err(EX_CANTCREAT, "cannot open %s", subj->subj_name);  in acquire_lock()
358  * Signal handler for SIGTERM.  Cleans up the lock file, then re-raises
369 	if (raise(sig) == -1)  in killed()
389 	child = -1;  in sigchld()
409 	    "usage: lockf [-knsw] [-t seconds] file command [arguments]\n"  in usage()
410 	    "       lockf [-s] [-t seconds] fd\n");  in usage()
423 	if ((fd = open(name, O_RDONLY|O_EXLOCK, 0666)) == -1) {  in wait_for_lock()