1 /* $NetBSD: linux_futex.c,v 1.7 2006/07/24 19:01:49 manu Exp $ */
2
3 /*-
4 * Copyright (c) 2005 Emmanuel Dreyfus, all rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. All advertising materials mentioning features or use of this software
15 * must display the following acknowledgement:
16 * This product includes software developed by Emmanuel Dreyfus
17 * 4. The name of the author may not be used to endorse or promote
18 * products derived from this software without specific prior written
19 * permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE THE AUTHOR AND CONTRIBUTORS ``AS IS''
22 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
23 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
24 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
25 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
31 * POSSIBILITY OF SUCH DAMAGE.
32 */
33
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD: releng/9.1/sys/compat/linux/linux_futex.c 219460 2011-03-10 19:50:12Z jhb $");
36 #if 0
37 __KERNEL_RCSID(1, "$NetBSD: linux_futex.c,v 1.7 2006/07/24 19:01:49 manu Exp $");
38 #endif
39
40 #include "opt_compat.h"
41
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/imgact.h>
45 #include <sys/kernel.h>
46 #include <sys/ktr.h>
47 #include <sys/lock.h>
48 #include <sys/malloc.h>
49 #include <sys/mutex.h>
50 #include <sys/priv.h>
51 #include <sys/proc.h>
52 #include <sys/queue.h>
53 #include <sys/sched.h>
54 #include <sys/sx.h>
55 #include <sys/umtx.h>
56
57 #ifdef COMPAT_LINUX32
58 #include <machine/../linux32/linux.h>
59 #include <machine/../linux32/linux32_proto.h>
60 #else
61 #include <machine/../linux/linux.h>
62 #include <machine/../linux/linux_proto.h>
63 #endif
64 #include <compat/linux/linux_emul.h>
65 #include <compat/linux/linux_futex.h>
66 #include <compat/linux/linux_util.h>
67
68 MALLOC_DEFINE(M_FUTEX, "futex", "Linux futexes");
69 MALLOC_DEFINE(M_FUTEX_WP, "futex wp", "Linux futexes wp");
70
71 struct futex;
72
73 struct waiting_proc {
74 uint32_t wp_flags;
75 struct futex *wp_futex;
76 TAILQ_ENTRY(waiting_proc) wp_list;
77 };
78
79 struct futex {
80 struct sx f_lck;
81 uint32_t *f_uaddr; /* user-supplied value, for debug */
82 struct umtx_key f_key;
83 uint32_t f_refcount;
84 uint32_t f_bitset;
85 LIST_ENTRY(futex) f_list;
86 TAILQ_HEAD(lf_waiting_proc, waiting_proc) f_waiting_proc;
87 };
88
89 struct futex_list futex_list;
90
91 #define FUTEX_LOCK(f) sx_xlock(&(f)->f_lck)
92 #define FUTEX_UNLOCK(f) sx_xunlock(&(f)->f_lck)
93 #define FUTEX_INIT(f) sx_init_flags(&(f)->f_lck, "ftlk", SX_DUPOK)
94 #define FUTEX_DESTROY(f) sx_destroy(&(f)->f_lck)
95 #define FUTEX_ASSERT_LOCKED(f) sx_assert(&(f)->f_lck, SA_XLOCKED)
96
97 struct mtx futex_mtx; /* protects the futex list */
98 #define FUTEXES_LOCK mtx_lock(&futex_mtx)
99 #define FUTEXES_UNLOCK mtx_unlock(&futex_mtx)
100
101 /* flags for futex_get() */
102 #define FUTEX_CREATE_WP 0x1 /* create waiting_proc */
103 #define FUTEX_DONTCREATE 0x2 /* don't create futex if not exists */
104 #define FUTEX_DONTEXISTS 0x4 /* return EINVAL if futex exists */
105 #define FUTEX_SHARED 0x8 /* shared futex */
106
107 /* wp_flags */
108 #define FUTEX_WP_REQUEUED 0x1 /* wp requeued - wp moved from wp_list
109 * of futex where thread sleep to wp_list
110 * of another futex.
111 */
112 #define FUTEX_WP_REMOVED 0x2 /* wp is woken up and removed from futex
113 * wp_list to prevent double wakeup.
114 */
115
116 /* support.s */
117 int futex_xchgl(int oparg, uint32_t *uaddr, int *oldval);
118 int futex_addl(int oparg, uint32_t *uaddr, int *oldval);
119 int futex_orl(int oparg, uint32_t *uaddr, int *oldval);
120 int futex_andl(int oparg, uint32_t *uaddr, int *oldval);
121 int futex_xorl(int oparg, uint32_t *uaddr, int *oldval);
122
123 static void
124 futex_put(struct futex *f, struct waiting_proc *wp)
125 {
126
127 FUTEX_ASSERT_LOCKED(f);
128 if (wp != NULL) {
129 if ((wp->wp_flags & FUTEX_WP_REMOVED) == 0)
130 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
131 free(wp, M_FUTEX_WP);
132 }
133
134 FUTEXES_LOCK;
135 if (--f->f_refcount == 0) {
136 LIST_REMOVE(f, f_list);
137 FUTEXES_UNLOCK;
138 FUTEX_UNLOCK(f);
139
140 LINUX_CTR3(sys_futex, "futex_put destroy uaddr %p ref %d "
141 "shared %d", f->f_uaddr, f->f_refcount, f->f_key.shared);
142 umtx_key_release(&f->f_key);
143 FUTEX_DESTROY(f);
144 free(f, M_FUTEX);
145 return;
146 }
147
148 LINUX_CTR3(sys_futex, "futex_put uaddr %p ref %d shared %d",
149 f->f_uaddr, f->f_refcount, f->f_key.shared);
150 FUTEXES_UNLOCK;
151 FUTEX_UNLOCK(f);
152 }
153
154 static int
155 futex_get0(uint32_t *uaddr, struct futex **newf, uint32_t flags)
156 {
157 struct futex *f, *tmpf;
158 struct umtx_key key;
159 int error;
160
161 *newf = tmpf = NULL;
162
163 error = umtx_key_get(uaddr, TYPE_FUTEX, (flags & FUTEX_SHARED) ?
164 AUTO_SHARE : THREAD_SHARE, &key);
165 if (error)
166 return (error);
167 retry:
168 FUTEXES_LOCK;
169 LIST_FOREACH(f, &futex_list, f_list) {
170 if (umtx_key_match(&f->f_key, &key)) {
171 if (tmpf != NULL) {
172 FUTEX_UNLOCK(tmpf);
173 FUTEX_DESTROY(tmpf);
174 free(tmpf, M_FUTEX);
175 }
176 if (flags & FUTEX_DONTEXISTS) {
177 FUTEXES_UNLOCK;
178 umtx_key_release(&key);
179 return (EINVAL);
180 }
181
182 /*
183 * Increment refcount of the found futex to
184 * prevent it from deallocation before FUTEX_LOCK()
185 */
186 ++f->f_refcount;
187 FUTEXES_UNLOCK;
188 umtx_key_release(&key);
189
190 FUTEX_LOCK(f);
191 *newf = f;
192 LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d",
193 uaddr, f->f_refcount, f->f_key.shared);
194 return (0);
195 }
196 }
197
198 if (flags & FUTEX_DONTCREATE) {
199 FUTEXES_UNLOCK;
200 umtx_key_release(&key);
201 LINUX_CTR1(sys_futex, "futex_get uaddr %p null", uaddr);
202 return (0);
203 }
204
205 if (tmpf == NULL) {
206 FUTEXES_UNLOCK;
207 tmpf = malloc(sizeof(*tmpf), M_FUTEX, M_WAITOK | M_ZERO);
208 tmpf->f_uaddr = uaddr;
209 tmpf->f_key = key;
210 tmpf->f_refcount = 1;
211 tmpf->f_bitset = FUTEX_BITSET_MATCH_ANY;
212 FUTEX_INIT(tmpf);
213 TAILQ_INIT(&tmpf->f_waiting_proc);
214
215 /*
216 * Lock the new futex before an insert into the futex_list
217 * to prevent futex usage by other.
218 */
219 FUTEX_LOCK(tmpf);
220 goto retry;
221 }
222
223 LIST_INSERT_HEAD(&futex_list, tmpf, f_list);
224 FUTEXES_UNLOCK;
225
226 LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d new",
227 uaddr, tmpf->f_refcount, tmpf->f_key.shared);
228 *newf = tmpf;
229 return (0);
230 }
231
232 static int
233 futex_get(uint32_t *uaddr, struct waiting_proc **wp, struct futex **f,
234 uint32_t flags)
235 {
236 int error;
237
238 if (flags & FUTEX_CREATE_WP) {
239 *wp = malloc(sizeof(struct waiting_proc), M_FUTEX_WP, M_WAITOK);
240 (*wp)->wp_flags = 0;
241 }
242 error = futex_get0(uaddr, f, flags);
243 if (error) {
244 if (flags & FUTEX_CREATE_WP)
245 free(*wp, M_FUTEX_WP);
246 return (error);
247 }
248 if (flags & FUTEX_CREATE_WP) {
249 TAILQ_INSERT_HEAD(&(*f)->f_waiting_proc, *wp, wp_list);
250 (*wp)->wp_futex = *f;
251 }
252
253 return (error);
254 }
255
256 static int
257 futex_sleep(struct futex *f, struct waiting_proc *wp, int timeout)
258 {
259 int error;
260
261 FUTEX_ASSERT_LOCKED(f);
262 LINUX_CTR4(sys_futex, "futex_sleep enter uaddr %p wp %p timo %d ref %d",
263 f->f_uaddr, wp, timeout, f->f_refcount);
264 error = sx_sleep(wp, &f->f_lck, PCATCH, "futex", timeout);
265 if (wp->wp_flags & FUTEX_WP_REQUEUED) {
266 KASSERT(f != wp->wp_futex, ("futex != wp_futex"));
267 LINUX_CTR5(sys_futex, "futex_sleep out error %d uaddr %p w"
268 " %p requeued uaddr %p ref %d",
269 error, f->f_uaddr, wp, wp->wp_futex->f_uaddr,
270 wp->wp_futex->f_refcount);
271 futex_put(f, NULL);
272 f = wp->wp_futex;
273 FUTEX_LOCK(f);
274 } else
275 LINUX_CTR3(sys_futex, "futex_sleep out error %d uaddr %p wp %p",
276 error, f->f_uaddr, wp);
277
278 futex_put(f, wp);
279 return (error);
280 }
281
282 static int
283 futex_wake(struct futex *f, int n, uint32_t bitset)
284 {
285 struct waiting_proc *wp, *wpt;
286 int count = 0;
287
288 if (bitset == 0)
289 return (EINVAL);
290
291 FUTEX_ASSERT_LOCKED(f);
292 TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) {
293 LINUX_CTR3(sys_futex, "futex_wake uaddr %p wp %p ref %d",
294 f->f_uaddr, wp, f->f_refcount);
295 /*
296 * Unless we find a matching bit in
297 * the bitset, continue searching.
298 */
299 if (!(wp->wp_futex->f_bitset & bitset))
300 continue;
301
302 wp->wp_flags |= FUTEX_WP_REMOVED;
303 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
304 wakeup_one(wp);
305 if (++count == n)
306 break;
307 }
308
309 return (count);
310 }
311
312 static int
313 futex_requeue(struct futex *f, int n, struct futex *f2, int n2)
314 {
315 struct waiting_proc *wp, *wpt;
316 int count = 0;
317
318 FUTEX_ASSERT_LOCKED(f);
319 FUTEX_ASSERT_LOCKED(f2);
320
321 TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) {
322 if (++count <= n) {
323 LINUX_CTR2(sys_futex, "futex_req_wake uaddr %p wp %p",
324 f->f_uaddr, wp);
325 wp->wp_flags |= FUTEX_WP_REMOVED;
326 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
327 wakeup_one(wp);
328 } else {
329 LINUX_CTR3(sys_futex, "futex_requeue uaddr %p wp %p to %p",
330 f->f_uaddr, wp, f2->f_uaddr);
331 wp->wp_flags |= FUTEX_WP_REQUEUED;
332 /* Move wp to wp_list of f2 futex */
333 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
334 TAILQ_INSERT_HEAD(&f2->f_waiting_proc, wp, wp_list);
335
336 /*
337 * Thread which sleeps on wp after waking should
338 * acquire f2 lock, so increment refcount of f2 to
339 * prevent it from premature deallocation.
340 */
341 wp->wp_futex = f2;
342 FUTEXES_LOCK;
343 ++f2->f_refcount;
344 FUTEXES_UNLOCK;
345 if (count - n >= n2)
346 break;
347 }
348 }
349
350 return (count);
351 }
352
353 static int
354 futex_wait(struct futex *f, struct waiting_proc *wp, struct l_timespec *ts,
355 uint32_t bitset)
356 {
357 struct l_timespec timeout;
358 struct timeval tv;
359 int timeout_hz;
360 int error;
361
362 if (bitset == 0)
363 return (EINVAL);
364 f->f_bitset = bitset;
365
366 if (ts != NULL) {
367 error = copyin(ts, &timeout, sizeof(timeout));
368 if (error)
369 return (error);
370 TIMESPEC_TO_TIMEVAL(&tv, &timeout);
371 error = itimerfix(&tv);
372 if (error)
373 return (error);
374 timeout_hz = tvtohz(&tv);
375 } else
376 timeout_hz = 0;
377
378 error = futex_sleep(f, wp, timeout_hz);
379 if (error == EWOULDBLOCK)
380 error = ETIMEDOUT;
381
382 return (error);
383 }
384
385 static int
386 futex_atomic_op(struct thread *td, int encoded_op, uint32_t *uaddr)
387 {
388 int op = (encoded_op >> 28) & 7;
389 int cmp = (encoded_op >> 24) & 15;
390 int oparg = (encoded_op << 8) >> 20;
391 int cmparg = (encoded_op << 20) >> 20;
392 int oldval = 0, ret;
393
394 if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
395 oparg = 1 << oparg;
396
397 #ifdef DEBUG
398 if (ldebug(sys_futex))
399 printf("futex_atomic_op: op = %d, cmp = %d, oparg = %x, "
400 "cmparg = %x, uaddr = %p\n",
401 op, cmp, oparg, cmparg, uaddr);
402 #endif
403 /* XXX: Linux verifies access here and returns EFAULT */
404
405 switch (op) {
406 case FUTEX_OP_SET:
407 ret = futex_xchgl(oparg, uaddr, &oldval);
408 break;
409 case FUTEX_OP_ADD:
410 ret = futex_addl(oparg, uaddr, &oldval);
411 break;
412 case FUTEX_OP_OR:
413 ret = futex_orl(oparg, uaddr, &oldval);
414 break;
415 case FUTEX_OP_ANDN:
416 ret = futex_andl(~oparg, uaddr, &oldval);
417 break;
418 case FUTEX_OP_XOR:
419 ret = futex_xorl(oparg, uaddr, &oldval);
420 break;
421 default:
422 ret = -ENOSYS;
423 break;
424 }
425
426 if (ret)
427 return (ret);
428
429 switch (cmp) {
430 case FUTEX_OP_CMP_EQ:
431 return (oldval == cmparg);
432 case FUTEX_OP_CMP_NE:
433 return (oldval != cmparg);
434 case FUTEX_OP_CMP_LT:
435 return (oldval < cmparg);
436 case FUTEX_OP_CMP_GE:
437 return (oldval >= cmparg);
438 case FUTEX_OP_CMP_LE:
439 return (oldval <= cmparg);
440 case FUTEX_OP_CMP_GT:
441 return (oldval > cmparg);
442 default:
443 return (-ENOSYS);
444 }
445 }
446
447 int
448 linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
449 {
450 int clockrt, nrwake, op_ret, ret, val;
451 struct linux_emuldata *em;
452 struct waiting_proc *wp;
453 struct futex *f, *f2;
454 int error;
455 uint32_t flags;
456
457 if (args->op & LINUX_FUTEX_PRIVATE_FLAG) {
458 flags = 0;
459 args->op &= ~LINUX_FUTEX_PRIVATE_FLAG;
460 } else
461 flags = FUTEX_SHARED;
462
463 /*
464 * Currently support for switching between CLOCK_MONOTONIC and
465 * CLOCK_REALTIME is not present. However Linux forbids the use of
466 * FUTEX_CLOCK_REALTIME with any op except FUTEX_WAIT_BITSET and
467 * FUTEX_WAIT_REQUEUE_PI.
468 */
469 clockrt = args->op & LINUX_FUTEX_CLOCK_REALTIME;
470 args->op = args->op & ~LINUX_FUTEX_CLOCK_REALTIME;
471 if (clockrt && args->op != LINUX_FUTEX_WAIT_BITSET &&
472 args->op != LINUX_FUTEX_WAIT_REQUEUE_PI)
473 return (ENOSYS);
474
475 error = 0;
476 f = f2 = NULL;
477
478 switch (args->op) {
479 case LINUX_FUTEX_WAIT:
480 args->val3 = FUTEX_BITSET_MATCH_ANY;
481 /* FALLTHROUGH */
482
483 case LINUX_FUTEX_WAIT_BITSET:
484
485 LINUX_CTR3(sys_futex, "WAIT uaddr %p val %d val3 %d",
486 args->uaddr, args->val, args->val3);
487 #ifdef DEBUG
488 if (ldebug(sys_futex))
489 printf(ARGS(sys_futex,
490 "futex_wait uaddr %p val %d val3 %d"),
491 args->uaddr, args->val, args->val3);
492 #endif
493 error = futex_get(args->uaddr, &wp, &f,
494 flags | FUTEX_CREATE_WP);
495 if (error)
496 return (error);
497 error = copyin(args->uaddr, &val, sizeof(val));
498 if (error) {
499 LINUX_CTR1(sys_futex, "WAIT copyin failed %d",
500 error);
501 futex_put(f, wp);
502 return (error);
503 }
504 if (val != args->val) {
505 LINUX_CTR4(sys_futex,
506 "WAIT uaddr %p val %d != uval %d val3 %d",
507 args->uaddr, args->val, val, args->val3);
508 futex_put(f, wp);
509 return (EWOULDBLOCK);
510 }
511
512 error = futex_wait(f, wp, args->timeout, args->val3);
513 break;
514
515 case LINUX_FUTEX_WAKE:
516 args->val3 = FUTEX_BITSET_MATCH_ANY;
517 /* FALLTHROUGH */
518
519 case LINUX_FUTEX_WAKE_BITSET:
520
521 LINUX_CTR3(sys_futex, "WAKE uaddr %p val % d val3 %d",
522 args->uaddr, args->val, args->val3);
523
524 #ifdef DEBUG
525 if (ldebug(sys_futex))
526 printf(ARGS(sys_futex, "futex_wake uaddr %p val %d val3 %d"),
527 args->uaddr, args->val, args->val3);
528 #endif
529 error = futex_get(args->uaddr, NULL, &f,
530 flags | FUTEX_DONTCREATE);
531 if (error)
532 return (error);
533 if (f == NULL) {
534 td->td_retval[0] = 0;
535 return (error);
536 }
537 td->td_retval[0] = futex_wake(f, args->val, args->val3);
538 futex_put(f, NULL);
539 break;
540
541 case LINUX_FUTEX_CMP_REQUEUE:
542
543 LINUX_CTR5(sys_futex, "CMP_REQUEUE uaddr %p "
544 "val %d val3 %d uaddr2 %p val2 %d",
545 args->uaddr, args->val, args->val3, args->uaddr2,
546 (int)(unsigned long)args->timeout);
547
548 #ifdef DEBUG
549 if (ldebug(sys_futex))
550 printf(ARGS(sys_futex, "futex_cmp_requeue uaddr %p "
551 "val %d val3 %d uaddr2 %p val2 %d"),
552 args->uaddr, args->val, args->val3, args->uaddr2,
553 (int)(unsigned long)args->timeout);
554 #endif
555
556 /*
557 * Linux allows this, we would not, it is an incorrect
558 * usage of declared ABI, so return EINVAL.
559 */
560 if (args->uaddr == args->uaddr2)
561 return (EINVAL);
562 error = futex_get(args->uaddr, NULL, &f, flags);
563 if (error)
564 return (error);
565
566 /*
567 * To avoid deadlocks return EINVAL if second futex
568 * exists at this time.
569 *
570 * Glibc fall back to FUTEX_WAKE in case of any error
571 * returned by FUTEX_CMP_REQUEUE.
572 */
573 error = futex_get(args->uaddr2, NULL, &f2,
574 flags | FUTEX_DONTEXISTS);
575 if (error) {
576 futex_put(f, NULL);
577 return (error);
578 }
579 error = copyin(args->uaddr, &val, sizeof(val));
580 if (error) {
581 LINUX_CTR1(sys_futex, "CMP_REQUEUE copyin failed %d",
582 error);
583 futex_put(f2, NULL);
584 futex_put(f, NULL);
585 return (error);
586 }
587 if (val != args->val3) {
588 LINUX_CTR2(sys_futex, "CMP_REQUEUE val %d != uval %d",
589 args->val, val);
590 futex_put(f2, NULL);
591 futex_put(f, NULL);
592 return (EAGAIN);
593 }
594
595 nrwake = (int)(unsigned long)args->timeout;
596 td->td_retval[0] = futex_requeue(f, args->val, f2, nrwake);
597 futex_put(f2, NULL);
598 futex_put(f, NULL);
599 break;
600
601 case LINUX_FUTEX_WAKE_OP:
602
603 LINUX_CTR5(sys_futex, "WAKE_OP "
604 "uaddr %p op %d val %x uaddr2 %p val3 %x",
605 args->uaddr, args->op, args->val,
606 args->uaddr2, args->val3);
607
608 #ifdef DEBUG
609 if (ldebug(sys_futex))
610 printf(ARGS(sys_futex, "futex_wake_op "
611 "uaddr %p op %d val %x uaddr2 %p val3 %x"),
612 args->uaddr, args->op, args->val,
613 args->uaddr2, args->val3);
614 #endif
615 error = futex_get(args->uaddr, NULL, &f, flags);
616 if (error)
617 return (error);
618 if (args->uaddr != args->uaddr2)
619 error = futex_get(args->uaddr2, NULL, &f2, flags);
620 if (error) {
621 futex_put(f, NULL);
622 return (error);
623 }
624
625 /*
626 * This function returns positive number as results and
627 * negative as errors
628 */
629 op_ret = futex_atomic_op(td, args->val3, args->uaddr2);
630
631 if (op_ret < 0) {
632 /* XXX: We don't handle the EFAULT yet. */
633 if (op_ret != -EFAULT) {
634 if (f2 != NULL)
635 futex_put(f2, NULL);
636 futex_put(f, NULL);
637 return (-op_ret);
638 }
639 if (f2 != NULL)
640 futex_put(f2, NULL);
641 futex_put(f, NULL);
642 return (EFAULT);
643 }
644
645 ret = futex_wake(f, args->val, args->val3);
646
647 if (op_ret > 0) {
648 op_ret = 0;
649 nrwake = (int)(unsigned long)args->timeout;
650
651 if (f2 != NULL)
652 op_ret += futex_wake(f2, nrwake, args->val3);
653 else
654 op_ret += futex_wake(f, nrwake, args->val3);
655 ret += op_ret;
656
657 }
658 if (f2 != NULL)
659 futex_put(f2, NULL);
660 futex_put(f, NULL);
661 td->td_retval[0] = ret;
662 break;
663
664 case LINUX_FUTEX_LOCK_PI:
665 /* not yet implemented */
666 linux_msg(td,
667 "linux_sys_futex: "
668 "op LINUX_FUTEX_LOCK_PI not implemented\n");
669 return (ENOSYS);
670
671 case LINUX_FUTEX_UNLOCK_PI:
672 /* not yet implemented */
673 linux_msg(td,
674 "linux_sys_futex: "
675 "op LINUX_FUTEX_UNLOCK_PI not implemented\n");
676 return (ENOSYS);
677
678 case LINUX_FUTEX_TRYLOCK_PI:
679 /* not yet implemented */
680 linux_msg(td,
681 "linux_sys_futex: "
682 "op LINUX_FUTEX_TRYLOCK_PI not implemented\n");
683 return (ENOSYS);
684
685 case LINUX_FUTEX_REQUEUE:
686
687 /*
688 * Glibc does not use this operation since version 2.3.3,
689 * as it is racy and replaced by FUTEX_CMP_REQUEUE operation.
690 * Glibc versions prior to 2.3.3 fall back to FUTEX_WAKE when
691 * FUTEX_REQUEUE returned EINVAL.
692 */
693 em = em_find(td->td_proc, EMUL_DONTLOCK);
694 if ((em->flags & LINUX_XDEPR_REQUEUEOP) == 0) {
695 linux_msg(td,
696 "linux_sys_futex: "
697 "unsupported futex_requeue op\n");
698 em->flags |= LINUX_XDEPR_REQUEUEOP;
699 }
700 return (EINVAL);
701
702 case LINUX_FUTEX_WAIT_REQUEUE_PI:
703 /* not yet implemented */
704 linux_msg(td,
705 "linux_sys_futex: "
706 "op FUTEX_WAIT_REQUEUE_PI not implemented\n");
707 return (ENOSYS);
708
709 case LINUX_FUTEX_CMP_REQUEUE_PI:
710 /* not yet implemented */
711 linux_msg(td,
712 "linux_sys_futex: "
713 "op LINUX_FUTEX_CMP_REQUEUE_PI not implemented\n");
714 return (ENOSYS);
715
716 default:
717 linux_msg(td,
718 "linux_sys_futex: unknown op %d\n", args->op);
719 return (ENOSYS);
720 }
721
722 return (error);
723 }
724
725 int
726 linux_set_robust_list(struct thread *td, struct linux_set_robust_list_args *args)
727 {
728 struct linux_emuldata *em;
729
730 #ifdef DEBUG
731 if (ldebug(set_robust_list))
732 printf(ARGS(set_robust_list, "head %p len %d"),
733 args->head, args->len);
734 #endif
735
736 if (args->len != sizeof(struct linux_robust_list_head))
737 return (EINVAL);
738
739 em = em_find(td->td_proc, EMUL_DOLOCK);
740 em->robust_futexes = args->head;
741 EMUL_UNLOCK(&emul_lock);
742
743 return (0);
744 }
745
746 int
747 linux_get_robust_list(struct thread *td, struct linux_get_robust_list_args *args)
748 {
749 struct linux_emuldata *em;
750 struct linux_robust_list_head *head;
751 l_size_t len = sizeof(struct linux_robust_list_head);
752 int error = 0;
753
754 #ifdef DEBUG
755 if (ldebug(get_robust_list))
756 printf(ARGS(get_robust_list, ""));
757 #endif
758
759 if (!args->pid) {
760 em = em_find(td->td_proc, EMUL_DONTLOCK);
761 head = em->robust_futexes;
762 } else {
763 struct proc *p;
764
765 p = pfind(args->pid);
766 if (p == NULL)
767 return (ESRCH);
768
769 em = em_find(p, EMUL_DONTLOCK);
770 /* XXX: ptrace? */
771 if (priv_check(td, PRIV_CRED_SETUID) ||
772 priv_check(td, PRIV_CRED_SETEUID) ||
773 p_candebug(td, p)) {
774 PROC_UNLOCK(p);
775 return (EPERM);
776 }
777 head = em->robust_futexes;
778
779 PROC_UNLOCK(p);
780 }
781
782 error = copyout(&len, args->len, sizeof(l_size_t));
783 if (error)
784 return (EFAULT);
785
786 error = copyout(head, args->head, sizeof(struct linux_robust_list_head));
787
788 return (error);
789 }
790
791 static int
792 handle_futex_death(struct proc *p, uint32_t *uaddr, int pi)
793 {
794 uint32_t uval, nval, mval;
795 struct futex *f;
796 int error;
797
798 retry:
799 if (copyin(uaddr, &uval, 4))
800 return (EFAULT);
801 if ((uval & FUTEX_TID_MASK) == p->p_pid) {
802 mval = (uval & FUTEX_WAITERS) | FUTEX_OWNER_DIED;
803 nval = casuword32(uaddr, uval, mval);
804
805 if (nval == -1)
806 return (EFAULT);
807
808 if (nval != uval)
809 goto retry;
810
811 if (!pi && (uval & FUTEX_WAITERS)) {
812 error = futex_get(uaddr, NULL, &f,
813 FUTEX_DONTCREATE | FUTEX_SHARED);
814 if (error)
815 return (error);
816 if (f != NULL) {
817 futex_wake(f, 1, FUTEX_BITSET_MATCH_ANY);
818 futex_put(f, NULL);
819 }
820 }
821 }
822
823 return (0);
824 }
825
826 static int
827 fetch_robust_entry(struct linux_robust_list **entry,
828 struct linux_robust_list **head, int *pi)
829 {
830 l_ulong uentry;
831
832 if (copyin((const void *)head, &uentry, sizeof(l_ulong)))
833 return (EFAULT);
834
835 *entry = (void *)(uentry & ~1UL);
836 *pi = uentry & 1;
837
838 return (0);
839 }
840
841 /* This walks the list of robust futexes releasing them. */
842 void
843 release_futexes(struct proc *p)
844 {
845 struct linux_robust_list_head *head = NULL;
846 struct linux_robust_list *entry, *next_entry, *pending;
847 unsigned int limit = 2048, pi, next_pi, pip;
848 struct linux_emuldata *em;
849 l_long futex_offset;
850 int rc;
851
852 em = em_find(p, EMUL_DONTLOCK);
853 head = em->robust_futexes;
854
855 if (head == NULL)
856 return;
857
858 if (fetch_robust_entry(&entry, PTRIN(&head->list.next), &pi))
859 return;
860
861 if (copyin(&head->futex_offset, &futex_offset, sizeof(futex_offset)))
862 return;
863
864 if (fetch_robust_entry(&pending, PTRIN(&head->pending_list), &pip))
865 return;
866
867 while (entry != &head->list) {
868 rc = fetch_robust_entry(&next_entry, PTRIN(&entry->next), &next_pi);
869
870 if (entry != pending)
871 if (handle_futex_death(p, (uint32_t *)entry + futex_offset, pi))
872 return;
873 if (rc)
874 return;
875
876 entry = next_entry;
877 pi = next_pi;
878
879 if (!--limit)
880 break;
881
882 sched_relinquish(curthread);
883 }
884
885 if (pending)
886 handle_futex_death(p, (uint32_t *)pending + futex_offset, pip);
887 }
Cache object: bf1ac9a6e88d8c94cd602e91d614f5d8
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