xref: /xnu-11215/tests/lockf_basic.c (revision 8d741a5d)
1 /*
2  * Copyright (c) 2022 Apple Inc. All rights reserved.
3  */
4 
5 #define PRIVATE 1 /* Needed for some F_OFD_* definitions */
6 #include <fcntl.h>
7 #include <sys/fcntl.h>
8 #include <errno.h>
9 #include <darwintest.h>
10 #include <darwintest_utils.h>
11 #include <stdatomic.h>
12 
13 #ifndef O_CLOFORK
14 #define O_CLOFORK       0x08000000
15 #endif
16 
17 T_GLOBAL_META(
18 	T_META_NAMESPACE("xnu.locks"),
19 	T_META_RADAR_COMPONENT_NAME("xnu"),
20 	T_META_RADAR_COMPONENT_VERSION("locks"),
21 	T_META_OWNER("tim_marsland"),   // with thanks to Peter Rutenbar
22 	T_META_RUN_CONCURRENTLY(TRUE));
23 
24 enum lock_flags {
25 	EXCL = 1,
26 	WAIT = 2,
27 	UNLOCK = 4,
28 };
29 
30 enum lock_type {
31 	TYPE_FLOCK = 0,
32 	TYPE_POSIX = 1,
33 	TYPE_OFD = 2,
34 };
35 
36 static int
ofd_get(struct flock * fl,int fd,off_t start,off_t len,pid_t pid,uint32_t flags)37 ofd_get(struct flock *fl,
38     int fd, off_t start, off_t len, pid_t pid, uint32_t flags)
39 {
40 	fl->l_start = start;
41 	fl->l_len = len;
42 	fl->l_pid = pid;
43 	fl->l_type = (flags & EXCL) ? F_WRLCK : F_RDLCK;
44 	fl->l_whence = SEEK_SET;
45 	return fcntl(fd, (pid == -1) ? F_OFD_GETLK : F_OFD_GETLKPID, fl);
46 }
47 
48 static int
posix_get(struct flock * fl,int fd,off_t start,off_t len,pid_t pid,uint32_t flags)49 posix_get(struct flock *fl,
50     int fd, off_t start, off_t len, pid_t pid, uint32_t flags)
51 {
52 	fl->l_start = start;
53 	fl->l_len = len;
54 	fl->l_pid = pid;
55 	fl->l_type = (flags & EXCL) ? F_WRLCK : F_RDLCK;
56 	fl->l_whence = SEEK_SET;
57 	return fcntl(fd, (pid == -1) ? F_GETLK : F_GETLKPID, fl);
58 }
59 
60 static int
posix_lock(int fd,off_t start,off_t len,uint32_t flags)61 posix_lock(int fd, off_t start, off_t len, uint32_t flags)
62 {
63 	struct flock fl = {
64 		.l_start = start,
65 		.l_len = len,
66 		.l_pid = -1,
67 		.l_type = (flags & EXCL) ? F_WRLCK : F_RDLCK,
68 		.l_whence = SEEK_SET,
69 	};
70 	return fcntl(fd, (flags & WAIT) ? F_SETLKW : F_SETLK, &fl);
71 }
72 
73 static int
ofd_lock(int fd,off_t start,off_t len,uint32_t flags)74 ofd_lock(int fd, off_t start, off_t len, uint32_t flags)
75 {
76 	struct flock fl = {
77 		.l_start = start,
78 		.l_len = len,
79 		.l_pid = -1,
80 		.l_type = (flags & EXCL) ? F_WRLCK : F_RDLCK,
81 		.l_whence = SEEK_SET,
82 	};
83 	return fcntl(fd, (flags & WAIT) ? F_OFD_SETLKW : F_OFD_SETLK, &fl);
84 }
85 
86 static int
posix_unlock(int fd,off_t start,off_t len)87 posix_unlock(int fd, off_t start, off_t len)
88 {
89 	struct flock fl = {
90 		.l_start = start,
91 		.l_len = len,
92 		.l_pid = -1,
93 		.l_type = F_UNLCK,
94 		.l_whence = SEEK_SET,
95 	};
96 	return fcntl(fd, F_SETLK, &fl);
97 }
98 
99 static int
ofd_unlock(int fd,off_t start,off_t len)100 ofd_unlock(int fd, off_t start, off_t len)
101 {
102 	struct flock fl = {
103 		.l_start = start,
104 		.l_len = len,
105 		.l_pid = -1,
106 		.l_type = F_UNLCK,
107 		.l_whence = SEEK_SET,
108 	};
109 	return fcntl(fd, F_OFD_SETLK, &fl);
110 }
111 
112 /* Is the given flock equal to the given arguments */
113 static bool
flequal(struct flock * fl,off_t start,off_t len,pid_t pid,int flags)114 flequal(struct flock *fl, off_t start, off_t len, pid_t pid, int flags)
115 {
116 	if (start == fl->l_start && len == fl->l_len && pid == fl->l_pid) {
117 		if (flags == EXCL && fl->l_type == F_WRLCK) {
118 			return true;
119 		} else if (flags == UNLOCK && fl->l_type == F_UNLCK) {
120 			return true;
121 		} else if (flags == 0 && fl->l_type == F_RDLCK) {
122 			return true;
123 		}
124 	}
125 	T_LOG("flequal: %lld %lld %d %x %x\n",
126 	    fl->l_start, fl->l_len, fl->l_pid, fl->l_type, fl->l_whence);
127 	return false;
128 }
129 
130 typedef struct {
131 	pthread_t thread;
132 	int fd, err;
133 	bool complete;
134 	enum lock_type lock_type;
135 	uint32_t flags;
136 	off_t start, end;
137 } lock_thread_state_t;
138 
139 static void *
lock_thread(void * arg)140 lock_thread(
141 	void *arg)
142 {
143 	lock_thread_state_t *lts = (lock_thread_state_t *)arg;
144 
145 	switch (lts->lock_type) {
146 	case TYPE_FLOCK: {
147 		int op = (lts->flags & EXCL) ? LOCK_EX : LOCK_SH;
148 		op |= (lts->flags & WAIT) ? 0 : LOCK_NB;
149 		lts->err = flock(lts->fd, op) ? errno : 0;
150 		break;
151 	}
152 	case TYPE_POSIX:
153 		lts->err = posix_lock(lts->fd,
154 		    lts->start, lts->end, lts->flags) ? errno : 0;
155 		break;
156 	case TYPE_OFD:
157 		lts->err = ofd_lock(lts->fd,
158 		    lts->start, lts->end, lts->flags) ? errno : 0;
159 		break;
160 	}
161 
162 	atomic_thread_fence(memory_order_acquire);
163 	lts->complete = true;
164 	atomic_thread_fence(memory_order_release);
165 
166 	return NULL;
167 }
168 
169 static bool
has_completed(lock_thread_state_t * lts)170 has_completed(lock_thread_state_t *lts)
171 {
172 	atomic_thread_fence(memory_order_acquire);
173 	const bool r = lts->complete;
174 	atomic_thread_fence(memory_order_release);
175 	return r;
176 }
177 
178 static void
start_lock_thread(enum lock_type type,lock_thread_state_t * lts,int fd,off_t start,off_t end,uint32_t flags)179 start_lock_thread(enum lock_type type, lock_thread_state_t *lts,
180     int fd, off_t start, off_t end, uint32_t flags)
181 {
182 	lts->fd = fd;
183 	lts->err = 0;
184 	lts->complete = false;
185 	lts->lock_type = type;
186 	lts->flags = flags;
187 	lts->start = start;
188 	lts->end = end;
189 
190 	pthread_create(&lts->thread, NULL, lock_thread, lts);
191 }
192 
193 static void
random_pause(void)194 random_pause(void)
195 {
196 	const useconds_t usec = rand() & (16384 - 1);
197 	usleep(usec + 1);
198 }
199 
200 #define GET_CHECK( \
201 		str, fd, \
202 		get_start, get_len, get_flags, get_type, \
203 		chk_start, chk_len, chk_flags, chk_pid) \
204 	do { \
205 	        struct flock _fl; \
206 	        if (get_type == TYPE_OFD) { \
207 	                T_ASSERT_POSIX_SUCCESS(ofd_get(&_fl, fd, get_start, get_len, -1, get_flags), str " (ofd_get)"); \
208 	        } else { \
209 	                T_ASSERT_POSIX_SUCCESS(posix_get(&_fl, fd, get_start, get_len, -1, get_flags), str " (posix_get)"); \
210 	        } \
211 	        T_ASSERT_TRUE(flequal(&_fl, chk_start, chk_len, chk_pid, chk_flags), str " (flequal)"); \
212 	} while (0)
213 
214 #define LOCK_AND_CHECK( \
215 		str, fd, \
216 		lck_start, lck_len, lck_flags, lock_type, \
217 		get_start, get_len, get_flags, get_type, \
218 		chk_start, chk_len, chk_flags, chk_pid) \
219 	do { \
220 	        if (lock_type == TYPE_OFD) { \
221 	                T_ASSERT_POSIX_SUCCESS(ofd_lock(fd, lck_start, lck_len, lck_flags), str " (ofd_lock)"); \
222 	        } else { \
223 	                T_ASSERT_POSIX_SUCCESS(posix_lock(fd, lck_start, lck_len, lck_flags), str " (posix_lock)"); \
224 	        } \
225 	        GET_CHECK(str, fd, get_start, get_len, get_flags, get_type, chk_start, chk_len, chk_flags, chk_pid); \
226 	} while (0)
227 
228 #define UNLOCK_AND_CHECK( \
229 		str, fd, \
230 		lck_start, lck_len, unlock_type, \
231 		get_start, get_len, get_flags, get_type, \
232 		chk_start, chk_len, chk_flags, chk_pid) \
233 	do { \
234 	        if (unlock_type == TYPE_OFD) { \
235 	                T_ASSERT_POSIX_SUCCESS(ofd_unlock(fd, lck_start, lck_len), str " (ofd_unlock)"); \
236 	        } else { \
237 	                T_ASSERT_POSIX_SUCCESS(posix_unlock(fd, lck_start, lck_len), str " (posix_unlock)"); \
238 	        } \
239 	        GET_CHECK(str, fd, get_start, get_len, get_flags, get_type, chk_start, chk_len, chk_flags, chk_pid); \
240 	} while (0)
241 
242 #define A_PATH "basic_lockf_a"
243 #define B_PATH "basic_lockf_b"
244 
245 T_DECL(lockf_basic,
246     "Basic test of flock/POSIX/OFD advisory file locks",
247     T_META_CHECK_LEAKS(false), T_META_TAG_VM_PREFERRED)
248 {
249 	const char *tmpdir = dt_tmpdir();
250 	lock_thread_state_t lts[4];
251 	pid_t pid = getpid();
252 	int a, a_confined, b, b_confined;
253 	const off_t file_len = 0x10000;
254 	T_SETUPBEGIN;
255 
256 	/* random sleeping to hunt for races */
257 
258 	unsigned seed = (unsigned)pid;
259 	const char *p = getenv("LOCKF_BASIC_SRAND_SEED");
260 	if (p) {
261 		seed = (unsigned)atol(p);
262 	}
263 	srand(seed);
264 
265 	/* Create two test files, a and b */
266 	T_ASSERT_POSIX_SUCCESS(chdir(tmpdir), "chdir(%s)", tmpdir);
267 	T_ASSERT_POSIX_SUCCESS((a = open(A_PATH, O_CREAT | O_RDWR, 0666)), "open(a)");
268 	T_ASSERT_POSIX_SUCCESS((b = open(B_PATH, O_CREAT | O_RDWR, 0666)), "open(b)");
269 
270 	/* Give both files 64KiB */
271 	T_ASSERT_POSIX_SUCCESS(ftruncate(a, file_len), "truncate a");
272 	T_ASSERT_POSIX_SUCCESS(ftruncate(b, 0x10000), "truncate b");
273 
274 	/* Open a/b again, but CONFINED this time */
275 	T_ASSERT_POSIX_SUCCESS((a_confined = open(A_PATH, O_CLOFORK | O_RDWR)), "open(a, O_CLOFORK)");
276 	T_ASSERT_POSIX_SUCCESS(fcntl(a_confined, F_SETCONFINED, 1), "F_SETCONFINED");
277 	T_ASSERT_POSIX_SUCCESS((b_confined = open(B_PATH, O_CLOFORK | O_RDWR)), "open(b, O_CLOFORK)");
278 	T_ASSERT_POSIX_SUCCESS(fcntl(b_confined, F_SETCONFINED, 1), "F_SETCONFINED");
279 
280 	T_SETUPEND;
281 
282 	/* Test all coalescence cases (non-upgrade/downgrade) */
283 
284 	/*
285 	 *   [   ]
286 	 * + [   ]
287 	 * = [   ]
288 	 */
289 	T_ASSERT_POSIX_SUCCESS(posix_lock(a, 130, 20, 0), "Coalesce: initial posix lock");
290 	LOCK_AND_CHECK("Coalesce: equal", a,
291 	    130, 20, 0, TYPE_POSIX,                        /* POSIX-lock a, shared, from [100..199] */
292 	    0, 0, EXCL, TYPE_OFD,                        /* OFD-get the entire file, exclusively */
293 	    130, 20, 0, pid);                        /* The result should be: [100..199] is locked shared by our PID */
294 
295 	/*
296 	 *   [   ]
297 	 * +     [   ]
298 	 * = [       ]
299 	 */
300 	LOCK_AND_CHECK("Coalesce: adjacent high", a,
301 	    150, 25, 0, TYPE_POSIX,
302 	    0, 0, EXCL, TYPE_OFD,
303 	    130, 45, 0, pid);
304 
305 	/*
306 	 *       [   ]
307 	 * + [   ]
308 	 * = [       ]
309 	 */
310 	LOCK_AND_CHECK("Coalesce: adjacent low", a,
311 	    125, 5, 0, TYPE_POSIX,
312 	    0, 0, EXCL, TYPE_OFD,
313 	    125, 50, 0, pid);
314 
315 	/*
316 	 *   [       ]
317 	 * +   [   ]
318 	 * = [       ]
319 	 */
320 	LOCK_AND_CHECK("Coalesce: subsume smaller", a,
321 	    150, 10, 0, TYPE_POSIX,
322 	    0, 0, EXCL, TYPE_OFD,
323 	    125, 50, 0, pid);
324 
325 	/*
326 	 *     [   ]
327 	 * + [       ]
328 	 * = [       ]
329 	 */
330 	LOCK_AND_CHECK("Coalesce: subsume larger", a,
331 	    100, 100, 0, TYPE_POSIX,
332 	    0, 0, EXCL, TYPE_OFD,
333 	    100, 100, 0, pid);
334 
335 	/*
336 	 *   [     ]
337 	 * + [          ]
338 	 * = [          ]
339 	 */
340 	LOCK_AND_CHECK("Coalesce: extend high", a,
341 	    100, 125, 0, TYPE_POSIX,
342 	    0, 0, EXCL, TYPE_OFD,
343 	    100, 125, 0, pid);
344 
345 	/*
346 	 *        [     ]
347 	 * + [          ]
348 	 * = [          ]
349 	 */
350 	LOCK_AND_CHECK("Coalesce: extend low", a,
351 	    75, 150, 0, TYPE_POSIX,
352 	    0, 0, EXCL, TYPE_OFD,
353 	    75, 150, 0, pid);
354 
355 	/*
356 	 *   [     ]
357 	 * +    [          ]
358 	 * = [             ]
359 	 */
360 	LOCK_AND_CHECK("Coalesce: overlap start", a,
361 	    50, 100, 0, TYPE_POSIX,
362 	    0, 0, EXCL, TYPE_OFD,
363 	    50, 175, 0, pid);
364 
365 	/*
366 	 *           [     ]
367 	 * + [          ]
368 	 * = [             ]
369 	 */
370 	LOCK_AND_CHECK("Coalesce: overlap end", a,
371 	    150, 100, 0, TYPE_POSIX,
372 	    0, 0, EXCL, TYPE_OFD,
373 	    50, 200, 0, pid);
374 
375 	/* Test all upgrade cases */
376 
377 	/*
378 	 *   [  R  ]
379 	 * +       [  W  ]
380 	 * = [  R  |  W  ]
381 	 */
382 	LOCK_AND_CHECK("Upgrade: adjacent high not-coalesced", a,
383 	    250, 50, EXCL, TYPE_POSIX, /* Take the posix lock exclusively */
384 	    50, 250, 0, TYPE_OFD,      /* and OFD-get shared */
385 	    250, 50, EXCL, pid);
386 
387 	/*
388 	 *         [  R  |  W  ]
389 	 * + [  W  ]
390 	 * = [  W  |  R  |  W  ]
391 	 */
392 	LOCK_AND_CHECK("Upgrade: adjacent low not-coalesced", a,
393 	    25, 25, EXCL, TYPE_POSIX,
394 	    25, 225, 0, TYPE_OFD,
395 	    25, 25, EXCL, pid);
396 
397 	/*
398 	 *  25      50      250     300
399 	 *   [   W   |   R   |   W   ]
400 	 * +               [ W ]
401 	 *   [   W   |  R  |    W    ]
402 	 *  25      50    225       300
403 	 */
404 	LOCK_AND_CHECK("Upgrade: truncate shared-end, grow excl-start", a,
405 	    225, 50, EXCL, TYPE_POSIX,
406 	    50, 250, 0, TYPE_OFD,
407 	    225, 75, EXCL, pid);
408 
409 	/*
410 	 *  25     50         225   300
411 	 *   [  W  |     R     |  W  ]
412 	 * +     [ W ]
413 	 * = [   W   |   R     |  W  ]
414 	 *  25      60        225   300
415 	 */
416 	LOCK_AND_CHECK("Upgrade: truncate shared-start, grow excl-end", a,
417 	    40, 20, EXCL, TYPE_POSIX,
418 	    0, 225, 0, TYPE_OFD,
419 	    25, 35, EXCL, pid);
420 
421 	/*
422 	 *  25    60              225   300
423 	 *   [  W  |       R       |  W  ]
424 	 * +             [ W ]
425 	 * = [  W  |     | W |     |  W  ]
426 	 *  25    60    100 150   225   300
427 	 */
428 	LOCK_AND_CHECK("Upgrade: 3-way split", a,
429 	    100, 50, EXCL, TYPE_POSIX,
430 	    60, 165, 0, TYPE_OFD,
431 	    100, 50, EXCL, pid);
432 
433 	/*
434 	 *  25    60    100 150   225   300
435 	 *   [  W  |     | W |     |  W  ]
436 	 * + [             W             ]
437 	 * = [             W             ]
438 	 *  25                          300
439 	 */
440 	LOCK_AND_CHECK("Upgrade: subsume multiple locks", a,
441 	    25, 275, EXCL, TYPE_POSIX,
442 	    0, 0, 0, TYPE_OFD,
443 	    25, 275, EXCL, pid);
444 
445 	/* Unlock / waiter-wakeup cases */
446 
447 	/*
448 	 *  25              300
449 	 *   [       W       ]
450 	 * +               [W (wait)]
451 	 *                290      310
452 	 */
453 	start_lock_thread(TYPE_OFD, &lts[0], a, 290, 20, EXCL | WAIT); /* Wait on this lock in another thread */
454 	random_pause();
455 	T_ASSERT_FALSE(has_completed(&lts[0]), "Unlock: created waiting lock");
456 
457 	/*
458 	 *  25              300
459 	 *   [       W       ]
460 	 * -                 [  -  ]
461 	 * = [       W       ]
462 	 *  25              300
463 	 */
464 	UNLOCK_AND_CHECK("Unlock: region with no locks", a,
465 	    300, 100, TYPE_POSIX,
466 	    0, 0, 0, TYPE_OFD,
467 	    25, 275, EXCL, pid);
468 	T_ASSERT_FALSE(has_completed(&lts[0]), "Unlock: waiter still waiting");
469 
470 	/*
471 	 *  25              300
472 	 *   [       W       ]
473 	 * -               [  -  ]
474 	 * = [      W      ]
475 	 *  25            250
476 	 */
477 	UNLOCK_AND_CHECK("Unlock: overlap end", a,
478 	    250, 100, TYPE_POSIX,
479 	    25, 1, 0, TYPE_OFD,
480 	    25, 225, EXCL, pid);
481 
482 	/*
483 	 *  25            250
484 	 *   [      W      ]
485 	 *                   [  W  ]
486 	 *                  290   310
487 	 */
488 
489 	while (!has_completed(&lts[0])) {
490 		random_pause();
491 	}
492 	T_ASSERT_TRUE(has_completed(&lts[0]), "Unlock: waiter woke up");
493 	T_ASSERT_POSIX_ZERO(lts[0].err, "Unlock: no err granting waiter");
494 	GET_CHECK("Unlock: waiter granted confirmation", a,
495 	    250, 100, 0, TYPE_POSIX,
496 	    290, 20, EXCL, -1); /* -1 because it's a non-CONFINED OFD lock (with no PID) */
497 
498 	T_ASSERT_POSIX_SUCCESS(ofd_unlock(a, 290, 20), "Unlock: unlock that now-granted waiter");
499 
500 	/*
501 	 *  25            250
502 	 *   [      W      ] 290   310
503 	 *                    [  W  ]
504 	 * -                  [  -  ]
505 	 * = [      W      ]
506 	 *  25            250
507 	 */
508 	UNLOCK_AND_CHECK("Unlock: equal range", a,
509 	    290, 20, TYPE_POSIX,
510 	    0, 0, 0, TYPE_OFD,
511 	    25, 225, EXCL, pid);
512 
513 	/*
514 	 *    25            250
515 	 *     [       W     ]
516 	 * - [ - ]
517 	 * =     [     W     ]
518 	 *      50          250
519 	 */
520 	UNLOCK_AND_CHECK("Unlock: overlap start", a,
521 	    0, 50, TYPE_POSIX,
522 	    0, 0, 0, TYPE_OFD,
523 	    50, 200, EXCL, pid);
524 
525 	/*
526 	 *  50          250
527 	 *   [     W     ]
528 	 * - [  ]
529 	 * =    [    W   ]
530 	 *     100      250
531 	 */
532 	UNLOCK_AND_CHECK("Unlock: start-aligned", a,
533 	    50, 50, TYPE_POSIX,
534 	    0, 0, 0, TYPE_OFD,
535 	    100, 150, EXCL, pid);
536 
537 	/*
538 	 *  100          250
539 	 *   [     W     ]
540 	 * -          [  ]
541 	 * = [   W    ]
542 	 *  100      200
543 	 */
544 	UNLOCK_AND_CHECK("Unlock: end-aligned", a,
545 	    200, 50, TYPE_POSIX,
546 	    0, 0, 0, TYPE_OFD,
547 	    100, 100, EXCL, pid);
548 
549 	/*
550 	 *  100             200
551 	 *   [       W       ]
552 	 * -       [   ]
553 	 * = [  W  ]   [  W  ]
554 	 *  100   125 175   200
555 	 */
556 	UNLOCK_AND_CHECK("Unlock: split", a,
557 	    125, 50, TYPE_POSIX,
558 	    0, 150, 0, TYPE_OFD,
559 	    100, 25, EXCL, pid);
560 
561 	/* Check the tail-fragment too */
562 	GET_CHECK("Unlock: split (tail-check)", a,
563 	    125, 200, 0, TYPE_OFD,
564 	    175, 25, EXCL, pid);
565 
566 	/*
567 	 *    100   125   175   200
568 	 *     [  W  ]     [  W  ]
569 	 * - [                     ]
570 	 * =        (no locks)
571 	 */
572 	UNLOCK_AND_CHECK("Unlock: multiple locks", a,
573 	    0, 0, TYPE_POSIX,
574 	    0, 0, 0, TYPE_OFD,
575 	    0, 0, UNLOCK, -1);
576 
577 
578 	/*
579 	 * Downgrade / waiter-wakeup test:
580 	 * The only interesting different between this and upgrade is that waiting locks
581 	 * may now be granted. So let's test that...
582 	 */
583 
584 	/*
585 	 *  Create this lock layout
586 	 *  0                                500
587 	 *  [                W                ]
588 	 *
589 	 *  0     100     200   300     400        600
590 	 *  [R(wait)]     [R(wait)]     [   R(wait)  ]
591 	 *
592 	 *      50                        450
593 	 *      [          R(wait)          ]
594 	 */
595 
596 	LOCK_AND_CHECK("Downgrade: first lock", a,
597 	    0, 500, EXCL, TYPE_POSIX,
598 	    0, 0, 0, TYPE_OFD,
599 	    0, 500, EXCL, pid);
600 
601 	start_lock_thread(TYPE_OFD, &lts[0], a, 0, 100, WAIT);
602 	start_lock_thread(TYPE_OFD, &lts[1], a, 200, 100, WAIT);
603 	start_lock_thread(TYPE_OFD, &lts[2], a, 400, 200, WAIT);
604 	start_lock_thread(TYPE_OFD, &lts[3], a, 50, 400, WAIT);
605 
606 	random_pause(); /* wait a bit to allow the lock threads to run */
607 
608 	T_ASSERT_FALSE(has_completed(&lts[0]), "Downgrade: waiter 0 waiting");;
609 	T_ASSERT_FALSE(has_completed(&lts[1]), "Downgrade: waiter 1 waiting");
610 	T_ASSERT_FALSE(has_completed(&lts[2]), "Downgrade: waiter 2 waiting");
611 	T_ASSERT_FALSE(has_completed(&lts[3]), "Downgrade: waiter 3 waiting");
612 
613 	/* Open a gap just wide enough for the [200..300] lock to be granted */
614 	T_ASSERT_POSIX_SUCCESS(posix_lock(a, 200, 100, 0), "Downgrade [200..300]");
615 
616 	/*
617 	 * (We can't use LOCK_AND_CHECK here, because there may be two shared locks
618 	 *  with that range (our downgrade, plus waiter #1) - so ofd_get() could return
619 	 *  either one non-deterministically.)
620 	 */
621 
622 	while (!has_completed(&lts[1])) {
623 		random_pause(); /* wait for waiter #1 to complete */
624 	}
625 	T_ASSERT_FALSE(has_completed(&lts[0]), "Downgrade: waiter 0 waiting");
626 	T_ASSERT_TRUE(has_completed(&lts[1]), "Downgrade: waiter 1 awoken");
627 	T_ASSERT_FALSE(has_completed(&lts[2]), "Downgrade: waiter 2 waiting");
628 	T_ASSERT_FALSE(has_completed(&lts[3]), "Downgrade: waiter 3 waiting");
629 
630 	/* Open a gap just wide enough for the [400..600] lock to be granted */
631 	T_ASSERT_POSIX_SUCCESS(posix_lock(a, 400, 100, 0), "Downgrade [400..500]");
632 
633 	while (!has_completed(&lts[2])) {
634 		random_pause(); /* wait for waiter #2 to complete */
635 	}
636 	T_ASSERT_FALSE(has_completed(&lts[0]), "Downgrade: waiter 0 waiting");
637 	T_ASSERT_TRUE(has_completed(&lts[2]), "Downgrade: waiter 2 awoken");
638 	T_ASSERT_FALSE(has_completed(&lts[3]), "Downgrade: waiter 3 waiting");
639 
640 	/* Downgrade the remaining chunks */
641 	T_ASSERT_POSIX_SUCCESS(posix_lock(a, 0, 500, 0), "Downgrade [0..500]");
642 
643 	while (!has_completed(&lts[0]) || !has_completed(&lts[3])) {
644 		random_pause(); /* wait for waiters #0 and #3 to complete */
645 	}
646 	T_ASSERT_TRUE(has_completed(&lts[0]), "Downgrade: waiter 0 awoken");
647 	T_ASSERT_TRUE(has_completed(&lts[3]), "Downgrade: waiter 3 awoken");
648 
649 	/* Unlock the remaining OFD shared locks */
650 	UNLOCK_AND_CHECK("Downgrade: cleanup (unlock all shared OFD locks)", a,
651 	    0, 0, TYPE_OFD,
652 	    0, 0, 0, TYPE_POSIX,
653 	    0, 0, UNLOCK, -1);
654 
655 	/* Unlock the remaining POSIX lock [0..500] */
656 	UNLOCK_AND_CHECK("Downgrade: cleanup (unlock all shared posix locks)", a,
657 	    0, 500, TYPE_POSIX,
658 	    0, 0, 0, TYPE_OFD,
659 	    0, 0, UNLOCK, -1);
660 
661 
662 	/* Test SEEK_END flock range decoding */
663 
664 	{
665 		/* SEEK_END start=-10 len=10 */
666 		struct flock fl = {.l_start = -10, .l_len = 10, .l_type = F_WRLCK, .l_whence = SEEK_END};
667 		T_ASSERT_POSIX_SUCCESS(fcntl(a, F_SETLK, &fl), "SEEK_END: -10, 10");
668 		GET_CHECK("SEEK_END: -10, 10 ", a,
669 		    0, 0, EXCL, TYPE_OFD,
670 		    file_len - 10, 10, EXCL, pid);
671 	}
672 
673 	{
674 		/* SEEK_END start=-10 len=10 */
675 		struct flock fl = {.l_start = -file_len, .l_len = file_len, .l_type = F_WRLCK, .l_whence = SEEK_END};
676 		T_ASSERT_POSIX_SUCCESS(fcntl(a, F_SETLK, &fl), "SEEK_END: -file_len, file_len");
677 		GET_CHECK("SEEK_END: -file_len, file_len", a,
678 		    0, 0, EXCL, TYPE_OFD,
679 		    0, file_len, EXCL, pid);
680 	}
681 
682 	{
683 		/* Negative case: SEEK_END start=-(file_len + 10) len=20 */
684 		struct flock fl = {.l_start = -(file_len + 10), .l_len = 20, .l_type = F_WRLCK, .l_whence = SEEK_END};
685 		T_EXPECT_TRUE(fcntl(a, F_SETLK, &fl) && errno == EINVAL, "SEEK_END: -(file_len + 10), 20 => EINVAL");
686 	}
687 
688 	T_ASSERT_POSIX_SUCCESS(posix_unlock(a, 0, 0), "SEEK_END: cleanup (release locks)");
689 
690 	/* Test interactions between all 3 lock types */
691 
692 	T_ASSERT_POSIX_SUCCESS(flock(a, LOCK_SH | LOCK_NB), "Interaction: flock(a, shared)");
693 
694 	/* Take (waiting) exclusive locks in all 3 types on a_confined */
695 	start_lock_thread(TYPE_FLOCK, &lts[0], a_confined, 0, 0, EXCL | WAIT);
696 	start_lock_thread(TYPE_POSIX, &lts[1], a_confined, 0, 0, EXCL | WAIT);
697 	start_lock_thread(TYPE_OFD, &lts[2], a_confined, 0, 0, EXCL | WAIT);
698 
699 	/* Yuck. Allow time for these threads to run -and- block on the flock lock */
700 	sleep(1);
701 
702 	/* Take shared locks in the remaining 2 types (posix/ofd) on a */
703 
704 	T_ASSERT_POSIX_SUCCESS(posix_lock(a, 0, 0, 0), "Interaction: posix_lock(a, 0, 0, 0)");
705 	T_ASSERT_POSIX_SUCCESS(ofd_lock(a, 0, 0, 0), "Interaction: ofd_lock(a, 0, 0, 0)");
706 
707 	T_ASSERT_FALSE(has_completed(&lts[0]), "Interaction: flock-waiter is starting or waiting");
708 	T_ASSERT_FALSE(has_completed(&lts[1]), "Interaction: posix-waiter is starting or waiting");
709 	T_ASSERT_FALSE(has_completed(&lts[2]), "Interaction: ofd-waiter is starting or waiting");
710 
711 	T_EXPECT_POSIX_FAILURE(flock(a, LOCK_EX | LOCK_NB), EAGAIN, "Interaction: can't flock-upgrade");
712 	T_EXPECT_POSIX_FAILURE(posix_lock(a, 0, 0, EXCL), EAGAIN, "Interaction: can't posix-upgrade");
713 	T_EXPECT_POSIX_FAILURE(ofd_lock(a, 0, 0, EXCL), EAGAIN, "Interaction: can't ofd-upgrade");
714 
715 	/*
716 	 * At this point:
717 	 * - 'a' owns a shared flock && a shared OFD lock
718 	 * - this process owns a shared POSIX lock
719 	 * - three threads are (hopefully) blocked waiting to take exclusive locks
720 	 *   on 'a_confined.'
721 	 *
722 	 * Drop the POSIX lock ...
723 	 */
724 	T_ASSERT_POSIX_SUCCESS(posix_unlock(a, 0, 0), "Interaction: Unlock posix");
725 
726 	random_pause(); /* wait a bit to see if there are consequences for the waiting locks */
727 
728 	T_ASSERT_FALSE(has_completed(&lts[0]), "Interaction: flock-waiter is still starting or waiting");
729 	T_ASSERT_FALSE(has_completed(&lts[1]), "Interaction: posix-waiter is still starting or waiting");
730 	T_ASSERT_FALSE(has_completed(&lts[2]), "Interaction: ofd-waiter is still starting or waiting");
731 
732 	/*
733 	 * and drop the flock lock ...
734 	 */
735 	T_ASSERT_POSIX_SUCCESS(flock(a, LOCK_UN), "Interaction: Unlock flock");
736 
737 	random_pause(); /* wait a bit to see if there are consequences for the waiting locks */
738 
739 	// Check that rdar://102160410 remains fixed.
740 	// Before that, the LOCK_UN above would release the OFD lock too
741 
742 	T_ASSERT_FALSE(has_completed(&lts[0]), "Interaction: flock-waiter is still starting or waiting");
743 	T_ASSERT_FALSE(has_completed(&lts[1]), "Interaction: posix-waiter is still starting or waiting");
744 	T_ASSERT_FALSE(has_completed(&lts[2]), "Interaction: ofd-waiter is still starting or waiting");
745 
746 	/*
747 	 * and finally drop the OFD lock, which should let one of the blocked threads
748 	 * acquire an exclusive lock. Work through them turn by turn.
749 	 */
750 	T_ASSERT_POSIX_SUCCESS(ofd_unlock(a, 0, 0), "Interaction: Unlock ofd");
751 
752 	bool unlocked[3] = {
753 		false, false, false
754 	};
755 
756 	for (uint32_t waiters = 3; waiters > 0; waiters--) {
757 		uint32_t num_waiting = 0;
758 		do {
759 			random_pause(); /* wait for consequences for the waiting locks */
760 			num_waiting = !has_completed(&lts[0]) + !has_completed(&lts[1]) + !has_completed(&lts[2]);
761 		} while (num_waiting == waiters);
762 
763 		T_ASSERT_EQ(num_waiting, waiters - 1, "Interaction: 1 waiter awoke");
764 
765 		if (has_completed(&lts[0]) && !unlocked[0]) {
766 			T_ASSERT_POSIX_SUCCESS(flock(a_confined, LOCK_UN), "Interaction: Flock awoke, unlocking");
767 			unlocked[0] = true;
768 		} else if (has_completed(&lts[1]) && !unlocked[1]) {
769 			T_ASSERT_POSIX_SUCCESS(posix_unlock(a_confined, 0, 0), "Interaction: posix awoke, unlocking");
770 			unlocked[1] = true;
771 		} else if (has_completed(&lts[2]) && !unlocked[2]) {
772 			T_ASSERT_POSIX_SUCCESS(ofd_unlock(a_confined, 0, 0), "Interaction: ofd awoke, unlocking");
773 			unlocked[2] = true;
774 		}
775 	}
776 
777 	T_ASSERT_TRUE(has_completed(&lts[0]), "Interaction: flock-waiter has completed");
778 	T_ASSERT_TRUE(unlocked[0], "Interaction: flock-waiter was unlocked");
779 
780 	T_ASSERT_TRUE(has_completed(&lts[1]), "Interaction: posix-waiter has completed");
781 	T_ASSERT_TRUE(unlocked[1], "Interaction: posix-waiter was unlocked");
782 
783 	T_ASSERT_TRUE(has_completed(&lts[2]), "Interaction: ofd-waiter has completed");
784 	T_ASSERT_TRUE(unlocked[2], "Interaction: ofd-waiter was unlocked");
785 }
786