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sys/compat/linux/linux_futex.c
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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("$FreeBSD$"); 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_futex.h> 65 #include <compat/linux/linux_emul.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 LIST_ENTRY(futex) f_list; 85 TAILQ_HEAD(lf_waiting_proc, waiting_proc) f_waiting_proc; 86 }; 87 88 struct futex_list futex_list; 89 90 #define FUTEX_LOCK(f) sx_xlock(&(f)->f_lck) 91 #define FUTEX_UNLOCK(f) sx_xunlock(&(f)->f_lck) 92 #define FUTEX_INIT(f) sx_init_flags(&(f)->f_lck, "ftlk", 0) 93 #define FUTEX_DESTROY(f) sx_destroy(&(f)->f_lck) 94 #define FUTEX_ASSERT_LOCKED(f) sx_assert(&(f)->f_lck, SA_XLOCKED) 95 96 struct mtx futex_mtx; /* protects the futex list */ 97 #define FUTEXES_LOCK mtx_lock(&futex_mtx) 98 #define FUTEXES_UNLOCK mtx_unlock(&futex_mtx) 99 100 /* flags for futex_get() */ 101 #define FUTEX_CREATE_WP 0x1 /* create waiting_proc */ 102 #define FUTEX_DONTCREATE 0x2 /* don't create futex if not exists */ 103 #define FUTEX_DONTEXISTS 0x4 /* return EINVAL if futex exists */ 104 #define FUTEX_SHARED 0x8 /* shared futex */ 105 106 /* wp_flags */ 107 #define FUTEX_WP_REQUEUED 0x1 /* wp requeued - wp moved from wp_list 108 * of futex where thread sleep to wp_list 109 * of another futex. 110 */ 111 #define FUTEX_WP_REMOVED 0x2 /* wp is woken up and removed from futex 112 * wp_list to prevent double wakeup. 113 */ 114 115 /* support.s */ 116 int futex_xchgl(int oparg, uint32_t *uaddr, int *oldval); 117 int futex_addl(int oparg, uint32_t *uaddr, int *oldval); 118 int futex_orl(int oparg, uint32_t *uaddr, int *oldval); 119 int futex_andl(int oparg, uint32_t *uaddr, int *oldval); 120 int futex_xorl(int oparg, uint32_t *uaddr, int *oldval); 121 122 static void 123 futex_put(struct futex *f, struct waiting_proc *wp) 124 { 125 126 FUTEX_ASSERT_LOCKED(f); 127 if (wp != NULL) { 128 if ((wp->wp_flags & FUTEX_WP_REMOVED) == 0) 129 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 130 free(wp, M_FUTEX_WP); 131 } 132 133 FUTEXES_LOCK; 134 if (--f->f_refcount == 0) { 135 LIST_REMOVE(f, f_list); 136 FUTEXES_UNLOCK; 137 FUTEX_UNLOCK(f); 138 139 LINUX_CTR2(sys_futex, "futex_put destroy uaddr %p ref %d", 140 f->f_uaddr, f->f_refcount); 141 umtx_key_release(&f->f_key); 142 FUTEX_DESTROY(f); 143 free(f, M_FUTEX); 144 return; 145 } 146 147 LINUX_CTR2(sys_futex, "futex_put uaddr %p ref %d", 148 f->f_uaddr, f->f_refcount); 149 FUTEXES_UNLOCK; 150 FUTEX_UNLOCK(f); 151 } 152 153 static int 154 futex_get0(uint32_t *uaddr, struct futex **newf, uint32_t flags) 155 { 156 struct futex *f, *tmpf; 157 struct umtx_key key; 158 int error; 159 160 *newf = tmpf = NULL; 161 162 error = umtx_key_get(uaddr, TYPE_FUTEX, (flags & FUTEX_SHARED) ? 163 AUTO_SHARE : THREAD_SHARE, &key); 164 if (error) 165 return (error); 166 retry: 167 FUTEXES_LOCK; 168 LIST_FOREACH(f, &futex_list, f_list) { 169 if (umtx_key_match(&f->f_key, &key)) { 170 if (tmpf != NULL) { 171 FUTEX_UNLOCK(tmpf); 172 FUTEX_DESTROY(tmpf); 173 free(tmpf, M_FUTEX); 174 } 175 if (flags & FUTEX_DONTEXISTS) { 176 FUTEXES_UNLOCK; 177 umtx_key_release(&key); 178 return (EINVAL); 179 } 180 181 /* 182 * Increment refcount of the found futex to 183 * prevent it from deallocation before FUTEX_LOCK() 184 */ 185 ++f->f_refcount; 186 FUTEXES_UNLOCK; 187 umtx_key_release(&key); 188 189 FUTEX_LOCK(f); 190 *newf = f; 191 LINUX_CTR2(sys_futex, "futex_get uaddr %p ref %d", 192 uaddr, f->f_refcount); 193 return (0); 194 } 195 } 196 197 if (flags & FUTEX_DONTCREATE) { 198 FUTEXES_UNLOCK; 199 umtx_key_release(&key); 200 LINUX_CTR1(sys_futex, "futex_get uaddr %p null", uaddr); 201 return (0); 202 } 203 204 if (tmpf == NULL) { 205 FUTEXES_UNLOCK; 206 tmpf = malloc(sizeof(*tmpf), M_FUTEX, M_WAITOK | M_ZERO); 207 tmpf->f_uaddr = uaddr; 208 tmpf->f_key = key; 209 tmpf->f_refcount = 1; 210 FUTEX_INIT(tmpf); 211 TAILQ_INIT(&tmpf->f_waiting_proc); 212 213 /* 214 * Lock the new futex before an insert into the futex_list 215 * to prevent futex usage by other. 216 */ 217 FUTEX_LOCK(tmpf); 218 goto retry; 219 } 220 221 LIST_INSERT_HEAD(&futex_list, tmpf, f_list); 222 FUTEXES_UNLOCK; 223 224 LINUX_CTR2(sys_futex, "futex_get uaddr %p ref %d new", 225 uaddr, tmpf->f_refcount); 226 *newf = tmpf; 227 return (0); 228 } 229 230 static int 231 futex_get(uint32_t *uaddr, struct waiting_proc **wp, struct futex **f, 232 uint32_t flags) 233 { 234 int error; 235 236 if (flags & FUTEX_CREATE_WP) { 237 *wp = malloc(sizeof(struct waiting_proc), M_FUTEX_WP, M_WAITOK); 238 (*wp)->wp_flags = 0; 239 } 240 error = futex_get0(uaddr, f, flags); 241 if (error) { 242 if (flags & FUTEX_CREATE_WP) 243 free(*wp, M_FUTEX_WP); 244 return (error); 245 } 246 if (flags & FUTEX_CREATE_WP) { 247 TAILQ_INSERT_HEAD(&(*f)->f_waiting_proc, *wp, wp_list); 248 (*wp)->wp_futex = *f; 249 } 250 251 return (error); 252 } 253 254 static int 255 futex_sleep(struct futex *f, struct waiting_proc *wp, unsigned long timeout) 256 { 257 int error; 258 259 FUTEX_ASSERT_LOCKED(f); 260 LINUX_CTR4(sys_futex, "futex_sleep enter uaddr %p wp %p timo %ld ref %d", 261 f->f_uaddr, wp, timeout, f->f_refcount); 262 error = sx_sleep(wp, &f->f_lck, PCATCH, "futex", timeout); 263 if (wp->wp_flags & FUTEX_WP_REQUEUED) { 264 KASSERT(f != wp->wp_futex, ("futex != wp_futex")); 265 LINUX_CTR5(sys_futex, "futex_sleep out error %d uaddr %p w" 266 " %p requeued uaddr %p ref %d", 267 error, f->f_uaddr, wp, wp->wp_futex->f_uaddr, 268 wp->wp_futex->f_refcount); 269 futex_put(f, NULL); 270 f = wp->wp_futex; 271 FUTEX_LOCK(f); 272 } else 273 LINUX_CTR3(sys_futex, "futex_sleep out error %d uaddr %p wp %p", 274 error, f->f_uaddr, wp); 275 276 futex_put(f, wp); 277 return (error); 278 } 279 280 static int 281 futex_wake(struct futex *f, int n) 282 { 283 struct waiting_proc *wp, *wpt; 284 int count = 0; 285 286 FUTEX_ASSERT_LOCKED(f); 287 TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) { 288 LINUX_CTR3(sys_futex, "futex_wake uaddr %p wp %p ref %d", 289 f->f_uaddr, wp, f->f_refcount); 290 wp->wp_flags |= FUTEX_WP_REMOVED; 291 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 292 wakeup_one(wp); 293 if (++count == n) 294 break; 295 } 296 297 return (count); 298 } 299 300 static int 301 futex_requeue(struct futex *f, int n, struct futex *f2, int n2) 302 { 303 struct waiting_proc *wp, *wpt; 304 int count = 0; 305 306 FUTEX_ASSERT_LOCKED(f); 307 FUTEX_ASSERT_LOCKED(f2); 308 309 TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) { 310 if (++count <= n) { 311 LINUX_CTR2(sys_futex, "futex_req_wake uaddr %p wp %p", 312 f->f_uaddr, wp); 313 wp->wp_flags |= FUTEX_WP_REMOVED; 314 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 315 wakeup_one(wp); 316 } else { 317 LINUX_CTR3(sys_futex, "futex_requeue uaddr %p wp %p to %p", 318 f->f_uaddr, wp, f2->f_uaddr); 319 wp->wp_flags |= FUTEX_WP_REQUEUED; 320 /* Move wp to wp_list of f2 futex */ 321 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 322 TAILQ_INSERT_HEAD(&f2->f_waiting_proc, wp, wp_list); 323 324 /* 325 * Thread which sleeps on wp after waking should 326 * acquire f2 lock, so increment refcount of f2 to 327 * prevent it from premature deallocation. 328 */ 329 wp->wp_futex = f2; 330 FUTEXES_LOCK; 331 ++f2->f_refcount; 332 FUTEXES_UNLOCK; 333 if (count - n >= n2) 334 break; 335 } 336 } 337 338 return (count); 339 } 340 341 static int 342 futex_wait(struct futex *f, struct waiting_proc *wp, struct l_timespec *ts) 343 { 344 struct l_timespec timeout = {0, 0}; 345 struct timeval tv = {0, 0}; 346 int timeout_hz; 347 int error; 348 349 if (ts != NULL) { 350 error = copyin(ts, &timeout, sizeof(timeout)); 351 if (error) 352 return (error); 353 } 354 355 tv.tv_usec = timeout.tv_sec * 1000000 + timeout.tv_nsec / 1000; 356 timeout_hz = tvtohz(&tv); 357 358 if (timeout.tv_sec == 0 && timeout.tv_nsec == 0) 359 timeout_hz = 0; 360 361 /* 362 * If the user process requests a non null timeout, 363 * make sure we do not turn it into an infinite 364 * timeout because timeout_hz gets null. 365 * 366 * We use a minimal timeout of 1/hz. Maybe it would 367 * make sense to just return ETIMEDOUT without sleeping. 368 */ 369 if (((timeout.tv_sec != 0) || (timeout.tv_nsec != 0)) && 370 (timeout_hz == 0)) 371 timeout_hz = 1; 372 373 error = futex_sleep(f, wp, timeout_hz); 374 if (error == EWOULDBLOCK) 375 error = ETIMEDOUT; 376 377 return (error); 378 } 379 380 static int 381 futex_atomic_op(struct thread *td, int encoded_op, uint32_t *uaddr) 382 { 383 int op = (encoded_op >> 28) & 7; 384 int cmp = (encoded_op >> 24) & 15; 385 int oparg = (encoded_op << 8) >> 20; 386 int cmparg = (encoded_op << 20) >> 20; 387 int oldval = 0, ret; 388 389 if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) 390 oparg = 1 << oparg; 391 392 #ifdef DEBUG 393 if (ldebug(sys_futex)) 394 printf("futex_atomic_op: op = %d, cmp = %d, oparg = %x, " 395 "cmparg = %x, uaddr = %p\n", 396 op, cmp, oparg, cmparg, uaddr); 397 #endif 398 /* XXX: Linux verifies access here and returns EFAULT */ 399 400 switch (op) { 401 case FUTEX_OP_SET: 402 ret = futex_xchgl(oparg, uaddr, &oldval); 403 break; 404 case FUTEX_OP_ADD: 405 ret = futex_addl(oparg, uaddr, &oldval); 406 break; 407 case FUTEX_OP_OR: 408 ret = futex_orl(oparg, uaddr, &oldval); 409 break; 410 case FUTEX_OP_ANDN: 411 ret = futex_andl(~oparg, uaddr, &oldval); 412 break; 413 case FUTEX_OP_XOR: 414 ret = futex_xorl(oparg, uaddr, &oldval); 415 break; 416 default: 417 ret = -ENOSYS; 418 break; 419 } 420 421 if (ret) 422 return (ret); 423 424 switch (cmp) { 425 case FUTEX_OP_CMP_EQ: 426 return (oldval == cmparg); 427 case FUTEX_OP_CMP_NE: 428 return (oldval != cmparg); 429 case FUTEX_OP_CMP_LT: 430 return (oldval < cmparg); 431 case FUTEX_OP_CMP_GE: 432 return (oldval >= cmparg); 433 case FUTEX_OP_CMP_LE: 434 return (oldval <= cmparg); 435 case FUTEX_OP_CMP_GT: 436 return (oldval > cmparg); 437 default: 438 return (-ENOSYS); 439 } 440 } 441 442 int 443 linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args) 444 { 445 int op_ret, val, ret, nrwake; 446 struct linux_emuldata *em; 447 struct waiting_proc *wp; 448 struct futex *f, *f2; 449 int error = 0; 450 uint32_t flags; 451 452 if (args->op & LINUX_FUTEX_PRIVATE_FLAG) { 453 flags = 0; 454 args->op &= ~LINUX_FUTEX_PRIVATE_FLAG; 455 } else 456 flags = FUTEX_SHARED; 457 458 switch (args->op) { 459 case LINUX_FUTEX_WAIT: 460 461 LINUX_CTR2(sys_futex, "WAIT val %d uaddr %p", 462 args->val, args->uaddr); 463 #ifdef DEBUG 464 if (ldebug(sys_futex)) 465 printf(ARGS(sys_futex, "futex_wait val %d uaddr %p"), 466 args->val, args->uaddr); 467 #endif 468 error = futex_get(args->uaddr, &wp, &f, 469 flags | FUTEX_CREATE_WP); 470 if (error) 471 return (error); 472 error = copyin(args->uaddr, &val, sizeof(val)); 473 if (error) { 474 LINUX_CTR1(sys_futex, "WAIT copyin failed %d", 475 error); 476 futex_put(f, wp); 477 return (error); 478 } 479 if (val != args->val) { 480 LINUX_CTR3(sys_futex, "WAIT uaddr %p val %d != uval %d", 481 args->uaddr, args->val, val); 482 futex_put(f, wp); 483 return (EWOULDBLOCK); 484 } 485 486 error = futex_wait(f, wp, args->timeout); 487 break; 488 489 case LINUX_FUTEX_WAKE: 490 491 LINUX_CTR2(sys_futex, "WAKE val %d uaddr %p", 492 args->val, args->uaddr); 493 494 #ifdef DEBUG 495 if (ldebug(sys_futex)) 496 printf(ARGS(sys_futex, "futex_wake val %d uaddr %p"), 497 args->val, args->uaddr); 498 #endif 499 error = futex_get(args->uaddr, NULL, &f, 500 flags | FUTEX_DONTCREATE); 501 if (error) 502 return (error); 503 if (f == NULL) { 504 td->td_retval[0] = 0; 505 return (error);; 506 } 507 td->td_retval[0] = futex_wake(f, args->val); 508 futex_put(f, NULL); 509 break; 510 511 case LINUX_FUTEX_CMP_REQUEUE: 512 513 LINUX_CTR5(sys_futex, "CMP_REQUEUE uaddr %p " 514 "val %d val3 %d uaddr2 %p val2 %d", 515 args->uaddr, args->val, args->val3, args->uaddr2, 516 (int)(unsigned long)args->timeout); 517 518 #ifdef DEBUG 519 if (ldebug(sys_futex)) 520 printf(ARGS(sys_futex, "futex_cmp_requeue uaddr %p " 521 "val %d val3 %d uaddr2 %p val2 %d"), 522 args->uaddr, args->val, args->val3, args->uaddr2, 523 (int)(unsigned long)args->timeout); 524 #endif 525 526 /* 527 * Linux allows this, we would not, it is an incorrect 528 * usage of declared ABI, so return EINVAL. 529 */ 530 if (args->uaddr == args->uaddr2) 531 return (EINVAL); 532 error = futex_get(args->uaddr, NULL, &f, flags); 533 if (error) 534 return (error); 535 536 /* 537 * To avoid deadlocks return EINVAL if second futex 538 * exists at this time. Otherwise create the new futex 539 * and ignore false positive LOR which thus happens. 540 * 541 * Glibc fall back to FUTEX_WAKE in case of any error 542 * returned by FUTEX_CMP_REQUEUE. 543 */ 544 error = futex_get(args->uaddr2, NULL, &f2, 545 flags | FUTEX_DONTEXISTS); 546 if (error) { 547 futex_put(f, NULL); 548 return (error); 549 } 550 error = copyin(args->uaddr, &val, sizeof(val)); 551 if (error) { 552 LINUX_CTR1(sys_futex, "CMP_REQUEUE copyin failed %d", 553 error); 554 futex_put(f2, NULL); 555 futex_put(f, NULL); 556 return (error); 557 } 558 if (val != args->val3) { 559 LINUX_CTR2(sys_futex, "CMP_REQUEUE val %d != uval %d", 560 args->val, val); 561 futex_put(f2, NULL); 562 futex_put(f, NULL); 563 return (EAGAIN); 564 } 565 566 nrwake = (int)(unsigned long)args->timeout; 567 td->td_retval[0] = futex_requeue(f, args->val, f2, nrwake); 568 futex_put(f2, NULL); 569 futex_put(f, NULL); 570 break; 571 572 case LINUX_FUTEX_WAKE_OP: 573 574 LINUX_CTR5(sys_futex, "WAKE_OP " 575 "uaddr %p op %d val %x uaddr2 %p val3 %x", 576 args->uaddr, args->op, args->val, 577 args->uaddr2, args->val3); 578 579 #ifdef DEBUG 580 if (ldebug(sys_futex)) 581 printf(ARGS(sys_futex, "futex_wake_op " 582 "uaddr %p op %d val %x uaddr2 %p val3 %x"), 583 args->uaddr, args->op, args->val, 584 args->uaddr2, args->val3); 585 #endif 586 error = futex_get(args->uaddr, NULL, &f, flags); 587 if (error) 588 return (error); 589 if (args->uaddr != args->uaddr2) 590 error = futex_get(args->uaddr2, NULL, &f2, flags); 591 if (error) { 592 futex_put(f, NULL); 593 return (error); 594 } 595 596 /* 597 * This function returns positive number as results and 598 * negative as errors 599 */ 600 op_ret = futex_atomic_op(td, args->val3, args->uaddr2); 601 602 if (op_ret < 0) { 603 /* XXX: We don't handle the EFAULT yet. */ 604 if (op_ret != -EFAULT) { 605 if (f2 != NULL) 606 futex_put(f2, NULL); 607 futex_put(f, NULL); 608 return (-op_ret); 609 } 610 if (f2 != NULL) 611 futex_put(f2, NULL); 612 futex_put(f, NULL); 613 return (EFAULT); 614 } 615 616 ret = futex_wake(f, args->val); 617 618 if (op_ret > 0) { 619 op_ret = 0; 620 nrwake = (int)(unsigned long)args->timeout; 621 622 if (f2 != NULL) 623 op_ret += futex_wake(f2, nrwake); 624 else 625 op_ret += futex_wake(f, nrwake); 626 ret += op_ret; 627 628 } 629 if (f2 != NULL) 630 futex_put(f2, NULL); 631 futex_put(f, NULL); 632 td->td_retval[0] = ret; 633 break; 634 635 case LINUX_FUTEX_LOCK_PI: 636 /* not yet implemented */ 637 return (ENOSYS); 638 639 case LINUX_FUTEX_UNLOCK_PI: 640 /* not yet implemented */ 641 return (ENOSYS); 642 643 case LINUX_FUTEX_TRYLOCK_PI: 644 /* not yet implemented */ 645 return (ENOSYS); 646 647 case LINUX_FUTEX_REQUEUE: 648 649 /* 650 * Glibc does not use this operation since version 2.3.3, 651 * as it is racy and replaced by FUTEX_CMP_REQUEUE operation. 652 * Glibc versions prior to 2.3.3 fall back to FUTEX_WAKE when 653 * FUTEX_REQUEUE returned EINVAL. 654 */ 655 em = em_find(td->td_proc, EMUL_DONTLOCK); 656 if (em->used_requeue == 0) { 657 printf("linux(%s (%d)) sys_futex: " 658 "unsupported futex_requeue op\n", 659 td->td_proc->p_comm, td->td_proc->p_pid); 660 em->used_requeue = 1; 661 } 662 return (EINVAL); 663 664 default: 665 printf("linux_sys_futex: unknown op %d\n", args->op); 666 return (ENOSYS); 667 } 668 669 return (error); 670 } 671 672 int 673 linux_set_robust_list(struct thread *td, struct linux_set_robust_list_args *args) 674 { 675 struct linux_emuldata *em; 676 677 #ifdef DEBUG 678 if (ldebug(set_robust_list)) 679 printf(ARGS(set_robust_list, "head %p len %d"), 680 args->head, args->len); 681 #endif 682 683 if (args->len != sizeof(struct linux_robust_list_head)) 684 return (EINVAL); 685 686 em = em_find(td->td_proc, EMUL_DOLOCK); 687 em->robust_futexes = args->head; 688 EMUL_UNLOCK(&emul_lock); 689 690 return (0); 691 } 692 693 int 694 linux_get_robust_list(struct thread *td, struct linux_get_robust_list_args *args) 695 { 696 struct linux_emuldata *em; 697 struct linux_robust_list_head *head; 698 l_size_t len = sizeof(struct linux_robust_list_head); 699 int error = 0; 700 701 #ifdef DEBUG 702 if (ldebug(get_robust_list)) 703 printf(ARGS(get_robust_list, "")); 704 #endif 705 706 if (!args->pid) { 707 em = em_find(td->td_proc, EMUL_DONTLOCK); 708 head = em->robust_futexes; 709 } else { 710 struct proc *p; 711 712 p = pfind(args->pid); 713 if (p == NULL) 714 return (ESRCH); 715 716 em = em_find(p, EMUL_DONTLOCK); 717 /* XXX: ptrace? */ 718 if (priv_check(td, PRIV_CRED_SETUID) || 719 priv_check(td, PRIV_CRED_SETEUID) || 720 p_candebug(td, p)) { 721 PROC_UNLOCK(p); 722 return (EPERM); 723 } 724 head = em->robust_futexes; 725 726 PROC_UNLOCK(p); 727 } 728 729 error = copyout(&len, args->len, sizeof(l_size_t)); 730 if (error) 731 return (EFAULT); 732 733 error = copyout(head, args->head, sizeof(struct linux_robust_list_head)); 734 735 return (error); 736 } 737 738 static int 739 handle_futex_death(struct proc *p, uint32_t *uaddr, int pi) 740 { 741 uint32_t uval, nval, mval; 742 struct futex *f; 743 int error; 744 745 retry: 746 if (copyin(uaddr, &uval, 4)) 747 return (EFAULT); 748 if ((uval & FUTEX_TID_MASK) == p->p_pid) { 749 mval = (uval & FUTEX_WAITERS) | FUTEX_OWNER_DIED; 750 nval = casuword32(uaddr, uval, mval); 751 752 if (nval == -1) 753 return (EFAULT); 754 755 if (nval != uval) 756 goto retry; 757 758 if (!pi && (uval & FUTEX_WAITERS)) { 759 error = futex_get(uaddr, NULL, &f, 760 FUTEX_DONTCREATE | FUTEX_SHARED); 761 if (error) 762 return (error); 763 if (f != NULL) { 764 futex_wake(f, 1); 765 futex_put(f, NULL); 766 } 767 } 768 } 769 770 return (0); 771 } 772 773 static int 774 fetch_robust_entry(struct linux_robust_list **entry, 775 struct linux_robust_list **head, int *pi) 776 { 777 l_ulong uentry; 778 779 if (copyin((const void *)head, &uentry, sizeof(l_ulong))) 780 return (EFAULT); 781 782 *entry = (void *)(uentry & ~1UL); 783 *pi = uentry & 1; 784 785 return (0); 786 } 787 788 /* This walks the list of robust futexes releasing them. */ 789 void 790 release_futexes(struct proc *p) 791 { 792 struct linux_robust_list_head *head = NULL; 793 struct linux_robust_list *entry, *next_entry, *pending; 794 unsigned int limit = 2048, pi, next_pi, pip; 795 struct linux_emuldata *em; 796 l_long futex_offset; 797 int rc; 798 799 em = em_find(p, EMUL_DONTLOCK); 800 head = em->robust_futexes; 801 802 if (head == NULL) 803 return; 804 805 if (fetch_robust_entry(&entry, PTRIN(&head->list.next), &pi)) 806 return; 807 808 if (copyin(&head->futex_offset, &futex_offset, sizeof(futex_offset))) 809 return; 810 811 if (fetch_robust_entry(&pending, PTRIN(&head->pending_list), &pip)) 812 return; 813 814 while (entry != &head->list) { 815 rc = fetch_robust_entry(&next_entry, PTRIN(&entry->next), &next_pi); 816 817 if (entry != pending) 818 if (handle_futex_death(p, (uint32_t *)entry + futex_offset, pi)) 819 return; 820 if (rc) 821 return; 822 823 entry = next_entry; 824 pi = next_pi; 825 826 if (!--limit) 827 break; 828 829 sched_relinquish(curthread); 830 } 831 832 if (pending) 833 handle_futex_death(p, (uint32_t *)pending + futex_offset, pip); 834 }
Cache object: 4a839f2e267fc46be8b55ee4c5542d4e
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