1 /* 2 * This file contains the procedures for the handling of select and poll 3 * 4 * Created for Linux based loosely upon Mathius Lattner's minix 5 * patches by Peter MacDonald. Heavily edited by Linus. 6 * 7 * 4 February 1994 8 * COFF/ELF binary emulation. If the process has the STICKY_TIMEOUTS 9 * flag set in its personality we do *not* modify the given timeout 10 * parameter to reflect time remaining. 11 * 12 * 24 January 2000 13 * Changed sys_poll()/do_poll() to use PAGE_SIZE chunk-based allocation 14 * of fds to overcome nfds < 16390 descriptors limit (Tigran Aivazian). 15 */ 16 17 #include <linux/kernel.h> 18 #include <linux/sched/signal.h> 19 #include <linux/sched/rt.h> 20 #include <linux/syscalls.h> 21 #include <linux/export.h> 22 #include <linux/slab.h> 23 #include <linux/poll.h> 24 #include <linux/personality.h> /* for STICKY_TIMEOUTS */ 25 #include <linux/file.h> 26 #include <linux/fdtable.h> 27 #include <linux/fs.h> 28 #include <linux/rcupdate.h> 29 #include <linux/hrtimer.h> 30 #include <linux/freezer.h> 31 #include <net/busy_poll.h> 32 #include <linux/vmalloc.h> 33 34 #include <linux/uaccess.h> 35 36 37 /* 38 * Estimate expected accuracy in ns from a timeval. 39 * 40 * After quite a bit of churning around, we've settled on 41 * a simple thing of taking 0.1% of the timeout as the 42 * slack, with a cap of 100 msec. 43 * "nice" tasks get a 0.5% slack instead. 44 * 45 * Consider this comment an open invitation to come up with even 46 * better solutions.. 47 */ 48 49 #define MAX_SLACK (100 * NSEC_PER_MSEC) 50 51 static long __estimate_accuracy(struct timespec64 *tv) 52 { 53 long slack; 54 int divfactor = 1000; 55 56 if (tv->tv_sec < 0) 57 return 0; 58 59 if (task_nice(current) > 0) 60 divfactor = divfactor / 5; 61 62 if (tv->tv_sec > MAX_SLACK / (NSEC_PER_SEC/divfactor)) 63 return MAX_SLACK; 64 65 slack = tv->tv_nsec / divfactor; 66 slack += tv->tv_sec * (NSEC_PER_SEC/divfactor); 67 68 if (slack > MAX_SLACK) 69 return MAX_SLACK; 70 71 return slack; 72 } 73 74 u64 select_estimate_accuracy(struct timespec64 *tv) 75 { 76 u64 ret; 77 struct timespec64 now; 78 79 /* 80 * Realtime tasks get a slack of 0 for obvious reasons. 81 */ 82 83 if (rt_task(current)) 84 return 0; 85 86 ktime_get_ts64(&now); 87 now = timespec64_sub(*tv, now); 88 ret = __estimate_accuracy(&now); 89 if (ret < current->timer_slack_ns) 90 return current->timer_slack_ns; 91 return ret; 92 } 93 94 95 96 struct poll_table_page { 97 struct poll_table_page * next; 98 struct poll_table_entry * entry; 99 struct poll_table_entry entries[0]; 100 }; 101 102 #define POLL_TABLE_FULL(table) \ 103 ((unsigned long)((table)->entry+1) > PAGE_SIZE + (unsigned long)(table)) 104 105 /* 106 * Ok, Peter made a complicated, but straightforward multiple_wait() function. 107 * I have rewritten this, taking some shortcuts: This code may not be easy to 108 * follow, but it should be free of race-conditions, and it's practical. If you 109 * understand what I'm doing here, then you understand how the linux 110 * sleep/wakeup mechanism works. 111 * 112 * Two very simple procedures, poll_wait() and poll_freewait() make all the 113 * work. poll_wait() is an inline-function defined in <linux/poll.h>, 114 * as all select/poll functions have to call it to add an entry to the 115 * poll table. 116 */ 117 static void __pollwait(struct file *filp, wait_queue_head_t *wait_address, 118 poll_table *p); 119 120 void poll_initwait(struct poll_wqueues *pwq) 121 { 122 init_poll_funcptr(&pwq->pt, __pollwait); 123 pwq->polling_task = current; 124 pwq->triggered = 0; 125 pwq->error = 0; 126 pwq->table = NULL; 127 pwq->inline_index = 0; 128 } 129 EXPORT_SYMBOL(poll_initwait); 130 131 static void free_poll_entry(struct poll_table_entry *entry) 132 { 133 remove_wait_queue(entry->wait_address, &entry->wait); 134 fput(entry->filp); 135 } 136 137 void poll_freewait(struct poll_wqueues *pwq) 138 { 139 struct poll_table_page * p = pwq->table; 140 int i; 141 for (i = 0; i < pwq->inline_index; i++) 142 free_poll_entry(pwq->inline_entries + i); 143 while (p) { 144 struct poll_table_entry * entry; 145 struct poll_table_page *old; 146 147 entry = p->entry; 148 do { 149 entry--; 150 free_poll_entry(entry); 151 } while (entry > p->entries); 152 old = p; 153 p = p->next; 154 free_page((unsigned long) old); 155 } 156 } 157 EXPORT_SYMBOL(poll_freewait); 158 159 static struct poll_table_entry *poll_get_entry(struct poll_wqueues *p) 160 { 161 struct poll_table_page *table = p->table; 162 163 if (p->inline_index < N_INLINE_POLL_ENTRIES) 164 return p->inline_entries + p->inline_index++; 165 166 if (!table || POLL_TABLE_FULL(table)) { 167 struct poll_table_page *new_table; 168 169 new_table = (struct poll_table_page *) __get_free_page(GFP_KERNEL); 170 if (!new_table) { 171 p->error = -ENOMEM; 172 return NULL; 173 } 174 new_table->entry = new_table->entries; 175 new_table->next = table; 176 p->table = new_table; 177 table = new_table; 178 } 179 180 return table->entry++; 181 } 182 183 static int __pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key) 184 { 185 struct poll_wqueues *pwq = wait->private; 186 DECLARE_WAITQUEUE(dummy_wait, pwq->polling_task); 187 188 /* 189 * Although this function is called under waitqueue lock, LOCK 190 * doesn't imply write barrier and the users expect write 191 * barrier semantics on wakeup functions. The following 192 * smp_wmb() is equivalent to smp_wmb() in try_to_wake_up() 193 * and is paired with smp_store_mb() in poll_schedule_timeout. 194 */ 195 smp_wmb(); 196 pwq->triggered = 1; 197 198 /* 199 * Perform the default wake up operation using a dummy 200 * waitqueue. 201 * 202 * TODO: This is hacky but there currently is no interface to 203 * pass in @sync. @sync is scheduled to be removed and once 204 * that happens, wake_up_process() can be used directly. 205 */ 206 return default_wake_function(&dummy_wait, mode, sync, key); 207 } 208 209 static int pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key) 210 { 211 struct poll_table_entry *entry; 212 213 entry = container_of(wait, struct poll_table_entry, wait); 214 if (key && !((unsigned long)key & entry->key)) 215 return 0; 216 return __pollwake(wait, mode, sync, key); 217 } 218 219 /* Add a new entry */ 220 static void __pollwait(struct file *filp, wait_queue_head_t *wait_address, 221 poll_table *p) 222 { 223 struct poll_wqueues *pwq = container_of(p, struct poll_wqueues, pt); 224 struct poll_table_entry *entry = poll_get_entry(pwq); 225 if (!entry) 226 return; 227 entry->filp = get_file(filp); 228 entry->wait_address = wait_address; 229 entry->key = p->_key; 230 init_waitqueue_func_entry(&entry->wait, pollwake); 231 entry->wait.private = pwq; 232 add_wait_queue(wait_address, &entry->wait); 233 } 234 235 int poll_schedule_timeout(struct poll_wqueues *pwq, int state, 236 ktime_t *expires, unsigned long slack) 237 { 238 int rc = -EINTR; 239 240 set_current_state(state); 241 if (!pwq->triggered) 242 rc = schedule_hrtimeout_range(expires, slack, HRTIMER_MODE_ABS); 243 __set_current_state(TASK_RUNNING); 244 245 /* 246 * Prepare for the next iteration. 247 * 248 * The following smp_store_mb() serves two purposes. First, it's 249 * the counterpart rmb of the wmb in pollwake() such that data 250 * written before wake up is always visible after wake up. 251 * Second, the full barrier guarantees that triggered clearing 252 * doesn't pass event check of the next iteration. Note that 253 * this problem doesn't exist for the first iteration as 254 * add_wait_queue() has full barrier semantics. 255 */ 256 smp_store_mb(pwq->triggered, 0); 257 258 return rc; 259 } 260 EXPORT_SYMBOL(poll_schedule_timeout); 261 262 /** 263 * poll_select_set_timeout - helper function to setup the timeout value 264 * @to: pointer to timespec64 variable for the final timeout 265 * @sec: seconds (from user space) 266 * @nsec: nanoseconds (from user space) 267 * 268 * Note, we do not use a timespec for the user space value here, That 269 * way we can use the function for timeval and compat interfaces as well. 270 * 271 * Returns -EINVAL if sec/nsec are not normalized. Otherwise 0. 272 */ 273 int poll_select_set_timeout(struct timespec64 *to, time64_t sec, long nsec) 274 { 275 struct timespec64 ts = {.tv_sec = sec, .tv_nsec = nsec}; 276 277 if (!timespec64_valid(&ts)) 278 return -EINVAL; 279 280 /* Optimize for the zero timeout value here */ 281 if (!sec && !nsec) { 282 to->tv_sec = to->tv_nsec = 0; 283 } else { 284 ktime_get_ts64(to); 285 *to = timespec64_add_safe(*to, ts); 286 } 287 return 0; 288 } 289 290 static int poll_select_copy_remaining(struct timespec64 *end_time, 291 void __user *p, 292 int timeval, int ret) 293 { 294 struct timespec64 rts64; 295 struct timespec rts; 296 struct timeval rtv; 297 298 if (!p) 299 return ret; 300 301 if (current->personality & STICKY_TIMEOUTS) 302 goto sticky; 303 304 /* No update for zero timeout */ 305 if (!end_time->tv_sec && !end_time->tv_nsec) 306 return ret; 307 308 ktime_get_ts64(&rts64); 309 rts64 = timespec64_sub(*end_time, rts64); 310 if (rts64.tv_sec < 0) 311 rts64.tv_sec = rts64.tv_nsec = 0; 312 313 rts = timespec64_to_timespec(rts64); 314 315 if (timeval) { 316 if (sizeof(rtv) > sizeof(rtv.tv_sec) + sizeof(rtv.tv_usec)) 317 memset(&rtv, 0, sizeof(rtv)); 318 rtv.tv_sec = rts64.tv_sec; 319 rtv.tv_usec = rts64.tv_nsec / NSEC_PER_USEC; 320 321 if (!copy_to_user(p, &rtv, sizeof(rtv))) 322 return ret; 323 324 } else if (!copy_to_user(p, &rts, sizeof(rts))) 325 return ret; 326 327 /* 328 * If an application puts its timeval in read-only memory, we 329 * don't want the Linux-specific update to the timeval to 330 * cause a fault after the select has completed 331 * successfully. However, because we're not updating the 332 * timeval, we can't restart the system call. 333 */ 334 335 sticky: 336 if (ret == -ERESTARTNOHAND) 337 ret = -EINTR; 338 return ret; 339 } 340 341 /* 342 * Scalable version of the fd_set. 343 */ 344 345 typedef struct { 346 unsigned long *in, *out, *ex; 347 unsigned long *res_in, *res_out, *res_ex; 348 } fd_set_bits; 349 350 /* 351 * How many longwords for "nr" bits? 352 */ 353 #define FDS_BITPERLONG (8*sizeof(long)) 354 #define FDS_LONGS(nr) (((nr)+FDS_BITPERLONG-1)/FDS_BITPERLONG) 355 #define FDS_BYTES(nr) (FDS_LONGS(nr)*sizeof(long)) 356 357 /* 358 * We do a VERIFY_WRITE here even though we are only reading this time: 359 * we'll write to it eventually.. 360 * 361 * Use "unsigned long" accesses to let user-mode fd_set's be long-aligned. 362 */ 363 static inline 364 int get_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset) 365 { 366 nr = FDS_BYTES(nr); 367 if (ufdset) 368 return copy_from_user(fdset, ufdset, nr) ? -EFAULT : 0; 369 370 memset(fdset, 0, nr); 371 return 0; 372 } 373 374 static inline unsigned long __must_check 375 set_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset) 376 { 377 if (ufdset) 378 return __copy_to_user(ufdset, fdset, FDS_BYTES(nr)); 379 return 0; 380 } 381 382 static inline 383 void zero_fd_set(unsigned long nr, unsigned long *fdset) 384 { 385 memset(fdset, 0, FDS_BYTES(nr)); 386 } 387 388 #define FDS_IN(fds, n) (fds->in + n) 389 #define FDS_OUT(fds, n) (fds->out + n) 390 #define FDS_EX(fds, n) (fds->ex + n) 391 392 #define BITS(fds, n) (*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n)) 393 394 static int max_select_fd(unsigned long n, fd_set_bits *fds) 395 { 396 unsigned long *open_fds; 397 unsigned long set; 398 int max; 399 struct fdtable *fdt; 400 401 /* handle last in-complete long-word first */ 402 set = ~(~0UL << (n & (BITS_PER_LONG-1))); 403 n /= BITS_PER_LONG; 404 fdt = files_fdtable(current->files); 405 open_fds = fdt->open_fds + n; 406 max = 0; 407 if (set) { 408 set &= BITS(fds, n); 409 if (set) { 410 if (!(set & ~*open_fds)) 411 goto get_max; 412 return -EBADF; 413 } 414 } 415 while (n) { 416 open_fds--; 417 n--; 418 set = BITS(fds, n); 419 if (!set) 420 continue; 421 if (set & ~*open_fds) 422 return -EBADF; 423 if (max) 424 continue; 425 get_max: 426 do { 427 max++; 428 set >>= 1; 429 } while (set); 430 max += n * BITS_PER_LONG; 431 } 432 433 return max; 434 } 435 436 #define POLLIN_SET (POLLRDNORM | POLLRDBAND | POLLIN | POLLHUP | POLLERR) 437 #define POLLOUT_SET (POLLWRBAND | POLLWRNORM | POLLOUT | POLLERR) 438 #define POLLEX_SET (POLLPRI) 439 440 static inline void wait_key_set(poll_table *wait, unsigned long in, 441 unsigned long out, unsigned long bit, 442 unsigned int ll_flag) 443 { 444 wait->_key = POLLEX_SET | ll_flag; 445 if (in & bit) 446 wait->_key |= POLLIN_SET; 447 if (out & bit) 448 wait->_key |= POLLOUT_SET; 449 } 450 451 static int do_select(int n, fd_set_bits *fds, struct timespec64 *end_time) 452 { 453 ktime_t expire, *to = NULL; 454 struct poll_wqueues table; 455 poll_table *wait; 456 int retval, i, timed_out = 0; 457 u64 slack = 0; 458 unsigned int busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0; 459 unsigned long busy_start = 0; 460 461 rcu_read_lock(); 462 retval = max_select_fd(n, fds); 463 rcu_read_unlock(); 464 465 if (retval < 0) 466 return retval; 467 n = retval; 468 469 poll_initwait(&table); 470 wait = &table.pt; 471 if (end_time && !end_time->tv_sec && !end_time->tv_nsec) { 472 wait->_qproc = NULL; 473 timed_out = 1; 474 } 475 476 if (end_time && !timed_out) 477 slack = select_estimate_accuracy(end_time); 478 479 retval = 0; 480 for (;;) { 481 unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp; 482 bool can_busy_loop = false; 483 484 inp = fds->in; outp = fds->out; exp = fds->ex; 485 rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex; 486 487 for (i = 0; i < n; ++rinp, ++routp, ++rexp) { 488 unsigned long in, out, ex, all_bits, bit = 1, mask, j; 489 unsigned long res_in = 0, res_out = 0, res_ex = 0; 490 491 in = *inp++; out = *outp++; ex = *exp++; 492 all_bits = in | out | ex; 493 if (all_bits == 0) { 494 i += BITS_PER_LONG; 495 continue; 496 } 497 498 for (j = 0; j < BITS_PER_LONG; ++j, ++i, bit <<= 1) { 499 struct fd f; 500 if (i >= n) 501 break; 502 if (!(bit & all_bits)) 503 continue; 504 f = fdget(i); 505 if (f.file) { 506 const struct file_operations *f_op; 507 f_op = f.file->f_op; 508 mask = DEFAULT_POLLMASK; 509 if (f_op->poll) { 510 wait_key_set(wait, in, out, 511 bit, busy_flag); 512 mask = (*f_op->poll)(f.file, wait); 513 } 514 fdput(f); 515 if ((mask & POLLIN_SET) && (in & bit)) { 516 res_in |= bit; 517 retval++; 518 wait->_qproc = NULL; 519 } 520 if ((mask & POLLOUT_SET) && (out & bit)) { 521 res_out |= bit; 522 retval++; 523 wait->_qproc = NULL; 524 } 525 if ((mask & POLLEX_SET) && (ex & bit)) { 526 res_ex |= bit; 527 retval++; 528 wait->_qproc = NULL; 529 } 530 /* got something, stop busy polling */ 531 if (retval) { 532 can_busy_loop = false; 533 busy_flag = 0; 534 535 /* 536 * only remember a returned 537 * POLL_BUSY_LOOP if we asked for it 538 */ 539 } else if (busy_flag & mask) 540 can_busy_loop = true; 541 542 } 543 } 544 if (res_in) 545 *rinp = res_in; 546 if (res_out) 547 *routp = res_out; 548 if (res_ex) 549 *rexp = res_ex; 550 cond_resched(); 551 } 552 wait->_qproc = NULL; 553 if (retval || timed_out || signal_pending(current)) 554 break; 555 if (table.error) { 556 retval = table.error; 557 break; 558 } 559 560 /* only if found POLL_BUSY_LOOP sockets && not out of time */ 561 if (can_busy_loop && !need_resched()) { 562 if (!busy_start) { 563 busy_start = busy_loop_current_time(); 564 continue; 565 } 566 if (!busy_loop_timeout(busy_start)) 567 continue; 568 } 569 busy_flag = 0; 570 571 /* 572 * If this is the first loop and we have a timeout 573 * given, then we convert to ktime_t and set the to 574 * pointer to the expiry value. 575 */ 576 if (end_time && !to) { 577 expire = timespec64_to_ktime(*end_time); 578 to = &expire; 579 } 580 581 if (!poll_schedule_timeout(&table, TASK_INTERRUPTIBLE, 582 to, slack)) 583 timed_out = 1; 584 } 585 586 poll_freewait(&table); 587 588 return retval; 589 } 590 591 /* 592 * We can actually return ERESTARTSYS instead of EINTR, but I'd 593 * like to be certain this leads to no problems. So I return 594 * EINTR just for safety. 595 * 596 * Update: ERESTARTSYS breaks at least the xview clock binary, so 597 * I'm trying ERESTARTNOHAND which restart only when you want to. 598 */ 599 int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp, 600 fd_set __user *exp, struct timespec64 *end_time) 601 { 602 fd_set_bits fds; 603 void *bits; 604 int ret, max_fds; 605 size_t size, alloc_size; 606 struct fdtable *fdt; 607 /* Allocate small arguments on the stack to save memory and be faster */ 608 long stack_fds[SELECT_STACK_ALLOC/sizeof(long)]; 609 610 ret = -EINVAL; 611 if (n < 0) 612 goto out_nofds; 613 614 /* max_fds can increase, so grab it once to avoid race */ 615 rcu_read_lock(); 616 fdt = files_fdtable(current->files); 617 max_fds = fdt->max_fds; 618 rcu_read_unlock(); 619 if (n > max_fds) 620 n = max_fds; 621 622 /* 623 * We need 6 bitmaps (in/out/ex for both incoming and outgoing), 624 * since we used fdset we need to allocate memory in units of 625 * long-words. 626 */ 627 size = FDS_BYTES(n); 628 bits = stack_fds; 629 if (size > sizeof(stack_fds) / 6) { 630 /* Not enough space in on-stack array; must use kmalloc */ 631 ret = -ENOMEM; 632 if (size > (SIZE_MAX / 6)) 633 goto out_nofds; 634 635 alloc_size = 6 * size; 636 bits = kvmalloc(alloc_size, GFP_KERNEL); 637 if (!bits) 638 goto out_nofds; 639 } 640 fds.in = bits; 641 fds.out = bits + size; 642 fds.ex = bits + 2*size; 643 fds.res_in = bits + 3*size; 644 fds.res_out = bits + 4*size; 645 fds.res_ex = bits + 5*size; 646 647 if ((ret = get_fd_set(n, inp, fds.in)) || 648 (ret = get_fd_set(n, outp, fds.out)) || 649 (ret = get_fd_set(n, exp, fds.ex))) 650 goto out; 651 zero_fd_set(n, fds.res_in); 652 zero_fd_set(n, fds.res_out); 653 zero_fd_set(n, fds.res_ex); 654 655 ret = do_select(n, &fds, end_time); 656 657 if (ret < 0) 658 goto out; 659 if (!ret) { 660 ret = -ERESTARTNOHAND; 661 if (signal_pending(current)) 662 goto out; 663 ret = 0; 664 } 665 666 if (set_fd_set(n, inp, fds.res_in) || 667 set_fd_set(n, outp, fds.res_out) || 668 set_fd_set(n, exp, fds.res_ex)) 669 ret = -EFAULT; 670 671 out: 672 if (bits != stack_fds) 673 kvfree(bits); 674 out_nofds: 675 return ret; 676 } 677 678 SYSCALL_DEFINE5(select, int, n, fd_set __user *, inp, fd_set __user *, outp, 679 fd_set __user *, exp, struct timeval __user *, tvp) 680 { 681 struct timespec64 end_time, *to = NULL; 682 struct timeval tv; 683 int ret; 684 685 if (tvp) { 686 if (copy_from_user(&tv, tvp, sizeof(tv))) 687 return -EFAULT; 688 689 to = &end_time; 690 if (poll_select_set_timeout(to, 691 tv.tv_sec + (tv.tv_usec / USEC_PER_SEC), 692 (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC)) 693 return -EINVAL; 694 } 695 696 ret = core_sys_select(n, inp, outp, exp, to); 697 ret = poll_select_copy_remaining(&end_time, tvp, 1, ret); 698 699 return ret; 700 } 701 702 static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp, 703 fd_set __user *exp, struct timespec __user *tsp, 704 const sigset_t __user *sigmask, size_t sigsetsize) 705 { 706 sigset_t ksigmask, sigsaved; 707 struct timespec ts; 708 struct timespec64 ts64, end_time, *to = NULL; 709 int ret; 710 711 if (tsp) { 712 if (copy_from_user(&ts, tsp, sizeof(ts))) 713 return -EFAULT; 714 ts64 = timespec_to_timespec64(ts); 715 716 to = &end_time; 717 if (poll_select_set_timeout(to, ts64.tv_sec, ts64.tv_nsec)) 718 return -EINVAL; 719 } 720 721 if (sigmask) { 722 /* XXX: Don't preclude handling different sized sigset_t's. */ 723 if (sigsetsize != sizeof(sigset_t)) 724 return -EINVAL; 725 if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask))) 726 return -EFAULT; 727 728 sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP)); 729 sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); 730 } 731 732 ret = core_sys_select(n, inp, outp, exp, to); 733 ret = poll_select_copy_remaining(&end_time, tsp, 0, ret); 734 735 if (ret == -ERESTARTNOHAND) { 736 /* 737 * Don't restore the signal mask yet. Let do_signal() deliver 738 * the signal on the way back to userspace, before the signal 739 * mask is restored. 740 */ 741 if (sigmask) { 742 memcpy(¤t->saved_sigmask, &sigsaved, 743 sizeof(sigsaved)); 744 set_restore_sigmask(); 745 } 746 } else if (sigmask) 747 sigprocmask(SIG_SETMASK, &sigsaved, NULL); 748 749 return ret; 750 } 751 752 /* 753 * Most architectures can't handle 7-argument syscalls. So we provide a 754 * 6-argument version where the sixth argument is a pointer to a structure 755 * which has a pointer to the sigset_t itself followed by a size_t containing 756 * the sigset size. 757 */ 758 SYSCALL_DEFINE6(pselect6, int, n, fd_set __user *, inp, fd_set __user *, outp, 759 fd_set __user *, exp, struct timespec __user *, tsp, 760 void __user *, sig) 761 { 762 size_t sigsetsize = 0; 763 sigset_t __user *up = NULL; 764 765 if (sig) { 766 if (!access_ok(VERIFY_READ, sig, sizeof(void *)+sizeof(size_t)) 767 || __get_user(up, (sigset_t __user * __user *)sig) 768 || __get_user(sigsetsize, 769 (size_t __user *)(sig+sizeof(void *)))) 770 return -EFAULT; 771 } 772 773 return do_pselect(n, inp, outp, exp, tsp, up, sigsetsize); 774 } 775 776 #ifdef __ARCH_WANT_SYS_OLD_SELECT 777 struct sel_arg_struct { 778 unsigned long n; 779 fd_set __user *inp, *outp, *exp; 780 struct timeval __user *tvp; 781 }; 782 783 SYSCALL_DEFINE1(old_select, struct sel_arg_struct __user *, arg) 784 { 785 struct sel_arg_struct a; 786 787 if (copy_from_user(&a, arg, sizeof(a))) 788 return -EFAULT; 789 return sys_select(a.n, a.inp, a.outp, a.exp, a.tvp); 790 } 791 #endif 792 793 struct poll_list { 794 struct poll_list *next; 795 int len; 796 struct pollfd entries[0]; 797 }; 798 799 #define POLLFD_PER_PAGE ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd)) 800 801 /* 802 * Fish for pollable events on the pollfd->fd file descriptor. We're only 803 * interested in events matching the pollfd->events mask, and the result 804 * matching that mask is both recorded in pollfd->revents and returned. The 805 * pwait poll_table will be used by the fd-provided poll handler for waiting, 806 * if pwait->_qproc is non-NULL. 807 */ 808 static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait, 809 bool *can_busy_poll, 810 unsigned int busy_flag) 811 { 812 unsigned int mask; 813 int fd; 814 815 mask = 0; 816 fd = pollfd->fd; 817 if (fd >= 0) { 818 struct fd f = fdget(fd); 819 mask = POLLNVAL; 820 if (f.file) { 821 mask = DEFAULT_POLLMASK; 822 if (f.file->f_op->poll) { 823 pwait->_key = pollfd->events|POLLERR|POLLHUP; 824 pwait->_key |= busy_flag; 825 mask = f.file->f_op->poll(f.file, pwait); 826 if (mask & busy_flag) 827 *can_busy_poll = true; 828 } 829 /* Mask out unneeded events. */ 830 mask &= pollfd->events | POLLERR | POLLHUP; 831 fdput(f); 832 } 833 } 834 pollfd->revents = mask; 835 836 return mask; 837 } 838 839 static int do_poll(struct poll_list *list, struct poll_wqueues *wait, 840 struct timespec64 *end_time) 841 { 842 poll_table* pt = &wait->pt; 843 ktime_t expire, *to = NULL; 844 int timed_out = 0, count = 0; 845 u64 slack = 0; 846 unsigned int busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0; 847 unsigned long busy_start = 0; 848 849 /* Optimise the no-wait case */ 850 if (end_time && !end_time->tv_sec && !end_time->tv_nsec) { 851 pt->_qproc = NULL; 852 timed_out = 1; 853 } 854 855 if (end_time && !timed_out) 856 slack = select_estimate_accuracy(end_time); 857 858 for (;;) { 859 struct poll_list *walk; 860 bool can_busy_loop = false; 861 862 for (walk = list; walk != NULL; walk = walk->next) { 863 struct pollfd * pfd, * pfd_end; 864 865 pfd = walk->entries; 866 pfd_end = pfd + walk->len; 867 for (; pfd != pfd_end; pfd++) { 868 /* 869 * Fish for events. If we found one, record it 870 * and kill poll_table->_qproc, so we don't 871 * needlessly register any other waiters after 872 * this. They'll get immediately deregistered 873 * when we break out and return. 874 */ 875 if (do_pollfd(pfd, pt, &can_busy_loop, 876 busy_flag)) { 877 count++; 878 pt->_qproc = NULL; 879 /* found something, stop busy polling */ 880 busy_flag = 0; 881 can_busy_loop = false; 882 } 883 } 884 } 885 /* 886 * All waiters have already been registered, so don't provide 887 * a poll_table->_qproc to them on the next loop iteration. 888 */ 889 pt->_qproc = NULL; 890 if (!count) { 891 count = wait->error; 892 if (signal_pending(current)) 893 count = -EINTR; 894 } 895 if (count || timed_out) 896 break; 897 898 /* only if found POLL_BUSY_LOOP sockets && not out of time */ 899 if (can_busy_loop && !need_resched()) { 900 if (!busy_start) { 901 busy_start = busy_loop_current_time(); 902 continue; 903 } 904 if (!busy_loop_timeout(busy_start)) 905 continue; 906 } 907 busy_flag = 0; 908 909 /* 910 * If this is the first loop and we have a timeout 911 * given, then we convert to ktime_t and set the to 912 * pointer to the expiry value. 913 */ 914 if (end_time && !to) { 915 expire = timespec64_to_ktime(*end_time); 916 to = &expire; 917 } 918 919 if (!poll_schedule_timeout(wait, TASK_INTERRUPTIBLE, to, slack)) 920 timed_out = 1; 921 } 922 return count; 923 } 924 925 #define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \ 926 sizeof(struct pollfd)) 927 928 static int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds, 929 struct timespec64 *end_time) 930 { 931 struct poll_wqueues table; 932 int err = -EFAULT, fdcount, len, size; 933 /* Allocate small arguments on the stack to save memory and be 934 faster - use long to make sure the buffer is aligned properly 935 on 64 bit archs to avoid unaligned access */ 936 long stack_pps[POLL_STACK_ALLOC/sizeof(long)]; 937 struct poll_list *const head = (struct poll_list *)stack_pps; 938 struct poll_list *walk = head; 939 unsigned long todo = nfds; 940 941 if (nfds > rlimit(RLIMIT_NOFILE)) 942 return -EINVAL; 943 944 len = min_t(unsigned int, nfds, N_STACK_PPS); 945 for (;;) { 946 walk->next = NULL; 947 walk->len = len; 948 if (!len) 949 break; 950 951 if (copy_from_user(walk->entries, ufds + nfds-todo, 952 sizeof(struct pollfd) * walk->len)) 953 goto out_fds; 954 955 todo -= walk->len; 956 if (!todo) 957 break; 958 959 len = min(todo, POLLFD_PER_PAGE); 960 size = sizeof(struct poll_list) + sizeof(struct pollfd) * len; 961 walk = walk->next = kmalloc(size, GFP_KERNEL); 962 if (!walk) { 963 err = -ENOMEM; 964 goto out_fds; 965 } 966 } 967 968 poll_initwait(&table); 969 fdcount = do_poll(head, &table, end_time); 970 poll_freewait(&table); 971 972 for (walk = head; walk; walk = walk->next) { 973 struct pollfd *fds = walk->entries; 974 int j; 975 976 for (j = 0; j < walk->len; j++, ufds++) 977 if (__put_user(fds[j].revents, &ufds->revents)) 978 goto out_fds; 979 } 980 981 err = fdcount; 982 out_fds: 983 walk = head->next; 984 while (walk) { 985 struct poll_list *pos = walk; 986 walk = walk->next; 987 kfree(pos); 988 } 989 990 return err; 991 } 992 993 static long do_restart_poll(struct restart_block *restart_block) 994 { 995 struct pollfd __user *ufds = restart_block->poll.ufds; 996 int nfds = restart_block->poll.nfds; 997 struct timespec64 *to = NULL, end_time; 998 int ret; 999 1000 if (restart_block->poll.has_timeout) { 1001 end_time.tv_sec = restart_block->poll.tv_sec; 1002 end_time.tv_nsec = restart_block->poll.tv_nsec; 1003 to = &end_time; 1004 } 1005 1006 ret = do_sys_poll(ufds, nfds, to); 1007 1008 if (ret == -EINTR) { 1009 restart_block->fn = do_restart_poll; 1010 ret = -ERESTART_RESTARTBLOCK; 1011 } 1012 return ret; 1013 } 1014 1015 SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds, 1016 int, timeout_msecs) 1017 { 1018 struct timespec64 end_time, *to = NULL; 1019 int ret; 1020 1021 if (timeout_msecs >= 0) { 1022 to = &end_time; 1023 poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC, 1024 NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC)); 1025 } 1026 1027 ret = do_sys_poll(ufds, nfds, to); 1028 1029 if (ret == -EINTR) { 1030 struct restart_block *restart_block; 1031 1032 restart_block = ¤t->restart_block; 1033 restart_block->fn = do_restart_poll; 1034 restart_block->poll.ufds = ufds; 1035 restart_block->poll.nfds = nfds; 1036 1037 if (timeout_msecs >= 0) { 1038 restart_block->poll.tv_sec = end_time.tv_sec; 1039 restart_block->poll.tv_nsec = end_time.tv_nsec; 1040 restart_block->poll.has_timeout = 1; 1041 } else 1042 restart_block->poll.has_timeout = 0; 1043 1044 ret = -ERESTART_RESTARTBLOCK; 1045 } 1046 return ret; 1047 } 1048 1049 SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds, 1050 struct timespec __user *, tsp, const sigset_t __user *, sigmask, 1051 size_t, sigsetsize) 1052 { 1053 sigset_t ksigmask, sigsaved; 1054 struct timespec ts; 1055 struct timespec64 end_time, *to = NULL; 1056 int ret; 1057 1058 if (tsp) { 1059 if (copy_from_user(&ts, tsp, sizeof(ts))) 1060 return -EFAULT; 1061 1062 to = &end_time; 1063 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) 1064 return -EINVAL; 1065 } 1066 1067 if (sigmask) { 1068 /* XXX: Don't preclude handling different sized sigset_t's. */ 1069 if (sigsetsize != sizeof(sigset_t)) 1070 return -EINVAL; 1071 if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask))) 1072 return -EFAULT; 1073 1074 sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP)); 1075 sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); 1076 } 1077 1078 ret = do_sys_poll(ufds, nfds, to); 1079 1080 /* We can restart this syscall, usually */ 1081 if (ret == -EINTR) { 1082 /* 1083 * Don't restore the signal mask yet. Let do_signal() deliver 1084 * the signal on the way back to userspace, before the signal 1085 * mask is restored. 1086 */ 1087 if (sigmask) { 1088 memcpy(¤t->saved_sigmask, &sigsaved, 1089 sizeof(sigsaved)); 1090 set_restore_sigmask(); 1091 } 1092 ret = -ERESTARTNOHAND; 1093 } else if (sigmask) 1094 sigprocmask(SIG_SETMASK, &sigsaved, NULL); 1095 1096 ret = poll_select_copy_remaining(&end_time, tsp, 0, ret); 1097 1098 return ret; 1099 } 1100 1101 #ifdef CONFIG_COMPAT 1102 #define __COMPAT_NFDBITS (8 * sizeof(compat_ulong_t)) 1103 1104 static 1105 int compat_poll_select_copy_remaining(struct timespec *end_time, void __user *p, 1106 int timeval, int ret) 1107 { 1108 struct timespec ts; 1109 1110 if (!p) 1111 return ret; 1112 1113 if (current->personality & STICKY_TIMEOUTS) 1114 goto sticky; 1115 1116 /* No update for zero timeout */ 1117 if (!end_time->tv_sec && !end_time->tv_nsec) 1118 return ret; 1119 1120 ktime_get_ts(&ts); 1121 ts = timespec_sub(*end_time, ts); 1122 if (ts.tv_sec < 0) 1123 ts.tv_sec = ts.tv_nsec = 0; 1124 1125 if (timeval) { 1126 struct compat_timeval rtv; 1127 1128 rtv.tv_sec = ts.tv_sec; 1129 rtv.tv_usec = ts.tv_nsec / NSEC_PER_USEC; 1130 1131 if (!copy_to_user(p, &rtv, sizeof(rtv))) 1132 return ret; 1133 } else { 1134 struct compat_timespec rts; 1135 1136 rts.tv_sec = ts.tv_sec; 1137 rts.tv_nsec = ts.tv_nsec; 1138 1139 if (!copy_to_user(p, &rts, sizeof(rts))) 1140 return ret; 1141 } 1142 /* 1143 * If an application puts its timeval in read-only memory, we 1144 * don't want the Linux-specific update to the timeval to 1145 * cause a fault after the select has completed 1146 * successfully. However, because we're not updating the 1147 * timeval, we can't restart the system call. 1148 */ 1149 1150 sticky: 1151 if (ret == -ERESTARTNOHAND) 1152 ret = -EINTR; 1153 return ret; 1154 } 1155 1156 /* 1157 * Ooo, nasty. We need here to frob 32-bit unsigned longs to 1158 * 64-bit unsigned longs. 1159 */ 1160 static 1161 int compat_get_fd_set(unsigned long nr, compat_ulong_t __user *ufdset, 1162 unsigned long *fdset) 1163 { 1164 nr = DIV_ROUND_UP(nr, __COMPAT_NFDBITS); 1165 if (ufdset) { 1166 unsigned long odd; 1167 1168 if (!access_ok(VERIFY_WRITE, ufdset, nr*sizeof(compat_ulong_t))) 1169 return -EFAULT; 1170 1171 odd = nr & 1UL; 1172 nr &= ~1UL; 1173 while (nr) { 1174 unsigned long h, l; 1175 if (__get_user(l, ufdset) || __get_user(h, ufdset+1)) 1176 return -EFAULT; 1177 ufdset += 2; 1178 *fdset++ = h << 32 | l; 1179 nr -= 2; 1180 } 1181 if (odd && __get_user(*fdset, ufdset)) 1182 return -EFAULT; 1183 } else { 1184 /* Tricky, must clear full unsigned long in the 1185 * kernel fdset at the end, this makes sure that 1186 * actually happens. 1187 */ 1188 memset(fdset, 0, ((nr + 1) & ~1)*sizeof(compat_ulong_t)); 1189 } 1190 return 0; 1191 } 1192 1193 static 1194 int compat_set_fd_set(unsigned long nr, compat_ulong_t __user *ufdset, 1195 unsigned long *fdset) 1196 { 1197 unsigned long odd; 1198 nr = DIV_ROUND_UP(nr, __COMPAT_NFDBITS); 1199 1200 if (!ufdset) 1201 return 0; 1202 1203 odd = nr & 1UL; 1204 nr &= ~1UL; 1205 while (nr) { 1206 unsigned long h, l; 1207 l = *fdset++; 1208 h = l >> 32; 1209 if (__put_user(l, ufdset) || __put_user(h, ufdset+1)) 1210 return -EFAULT; 1211 ufdset += 2; 1212 nr -= 2; 1213 } 1214 if (odd && __put_user(*fdset, ufdset)) 1215 return -EFAULT; 1216 return 0; 1217 } 1218 1219 1220 /* 1221 * This is a virtual copy of sys_select from fs/select.c and probably 1222 * should be compared to it from time to time 1223 */ 1224 1225 /* 1226 * We can actually return ERESTARTSYS instead of EINTR, but I'd 1227 * like to be certain this leads to no problems. So I return 1228 * EINTR just for safety. 1229 * 1230 * Update: ERESTARTSYS breaks at least the xview clock binary, so 1231 * I'm trying ERESTARTNOHAND which restart only when you want to. 1232 */ 1233 static int compat_core_sys_select(int n, compat_ulong_t __user *inp, 1234 compat_ulong_t __user *outp, compat_ulong_t __user *exp, 1235 struct timespec *end_time) 1236 { 1237 fd_set_bits fds; 1238 void *bits; 1239 int size, max_fds, ret = -EINVAL; 1240 struct fdtable *fdt; 1241 long stack_fds[SELECT_STACK_ALLOC/sizeof(long)]; 1242 1243 if (n < 0) 1244 goto out_nofds; 1245 1246 /* max_fds can increase, so grab it once to avoid race */ 1247 rcu_read_lock(); 1248 fdt = files_fdtable(current->files); 1249 max_fds = fdt->max_fds; 1250 rcu_read_unlock(); 1251 if (n > max_fds) 1252 n = max_fds; 1253 1254 /* 1255 * We need 6 bitmaps (in/out/ex for both incoming and outgoing), 1256 * since we used fdset we need to allocate memory in units of 1257 * long-words. 1258 */ 1259 size = FDS_BYTES(n); 1260 bits = stack_fds; 1261 if (size > sizeof(stack_fds) / 6) { 1262 bits = kmalloc(6 * size, GFP_KERNEL); 1263 ret = -ENOMEM; 1264 if (!bits) 1265 goto out_nofds; 1266 } 1267 fds.in = (unsigned long *) bits; 1268 fds.out = (unsigned long *) (bits + size); 1269 fds.ex = (unsigned long *) (bits + 2*size); 1270 fds.res_in = (unsigned long *) (bits + 3*size); 1271 fds.res_out = (unsigned long *) (bits + 4*size); 1272 fds.res_ex = (unsigned long *) (bits + 5*size); 1273 1274 if ((ret = compat_get_fd_set(n, inp, fds.in)) || 1275 (ret = compat_get_fd_set(n, outp, fds.out)) || 1276 (ret = compat_get_fd_set(n, exp, fds.ex))) 1277 goto out; 1278 zero_fd_set(n, fds.res_in); 1279 zero_fd_set(n, fds.res_out); 1280 zero_fd_set(n, fds.res_ex); 1281 1282 ret = do_select(n, &fds, end_time); 1283 1284 if (ret < 0) 1285 goto out; 1286 if (!ret) { 1287 ret = -ERESTARTNOHAND; 1288 if (signal_pending(current)) 1289 goto out; 1290 ret = 0; 1291 } 1292 1293 if (compat_set_fd_set(n, inp, fds.res_in) || 1294 compat_set_fd_set(n, outp, fds.res_out) || 1295 compat_set_fd_set(n, exp, fds.res_ex)) 1296 ret = -EFAULT; 1297 out: 1298 if (bits != stack_fds) 1299 kfree(bits); 1300 out_nofds: 1301 return ret; 1302 } 1303 1304 COMPAT_SYSCALL_DEFINE5(select, int, n, compat_ulong_t __user *, inp, 1305 compat_ulong_t __user *, outp, compat_ulong_t __user *, exp, 1306 struct compat_timeval __user *, tvp) 1307 { 1308 struct timespec end_time, *to = NULL; 1309 struct compat_timeval tv; 1310 int ret; 1311 1312 if (tvp) { 1313 if (copy_from_user(&tv, tvp, sizeof(tv))) 1314 return -EFAULT; 1315 1316 to = &end_time; 1317 if (poll_select_set_timeout(to, 1318 tv.tv_sec + (tv.tv_usec / USEC_PER_SEC), 1319 (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC)) 1320 return -EINVAL; 1321 } 1322 1323 ret = compat_core_sys_select(n, inp, outp, exp, to); 1324 ret = compat_poll_select_copy_remaining(&end_time, tvp, 1, ret); 1325 1326 return ret; 1327 } 1328 1329 struct compat_sel_arg_struct { 1330 compat_ulong_t n; 1331 compat_uptr_t inp; 1332 compat_uptr_t outp; 1333 compat_uptr_t exp; 1334 compat_uptr_t tvp; 1335 }; 1336 1337 COMPAT_SYSCALL_DEFINE1(old_select, struct compat_sel_arg_struct __user *, arg) 1338 { 1339 struct compat_sel_arg_struct a; 1340 1341 if (copy_from_user(&a, arg, sizeof(a))) 1342 return -EFAULT; 1343 return compat_sys_select(a.n, compat_ptr(a.inp), compat_ptr(a.outp), 1344 compat_ptr(a.exp), compat_ptr(a.tvp)); 1345 } 1346 1347 static long do_compat_pselect(int n, compat_ulong_t __user *inp, 1348 compat_ulong_t __user *outp, compat_ulong_t __user *exp, 1349 struct compat_timespec __user *tsp, compat_sigset_t __user *sigmask, 1350 compat_size_t sigsetsize) 1351 { 1352 compat_sigset_t ss32; 1353 sigset_t ksigmask, sigsaved; 1354 struct compat_timespec ts; 1355 struct timespec end_time, *to = NULL; 1356 int ret; 1357 1358 if (tsp) { 1359 if (copy_from_user(&ts, tsp, sizeof(ts))) 1360 return -EFAULT; 1361 1362 to = &end_time; 1363 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) 1364 return -EINVAL; 1365 } 1366 1367 if (sigmask) { 1368 if (sigsetsize != sizeof(compat_sigset_t)) 1369 return -EINVAL; 1370 if (copy_from_user(&ss32, sigmask, sizeof(ss32))) 1371 return -EFAULT; 1372 sigset_from_compat(&ksigmask, &ss32); 1373 1374 sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP)); 1375 sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); 1376 } 1377 1378 ret = compat_core_sys_select(n, inp, outp, exp, to); 1379 ret = compat_poll_select_copy_remaining(&end_time, tsp, 0, ret); 1380 1381 if (ret == -ERESTARTNOHAND) { 1382 /* 1383 * Don't restore the signal mask yet. Let do_signal() deliver 1384 * the signal on the way back to userspace, before the signal 1385 * mask is restored. 1386 */ 1387 if (sigmask) { 1388 memcpy(¤t->saved_sigmask, &sigsaved, 1389 sizeof(sigsaved)); 1390 set_restore_sigmask(); 1391 } 1392 } else if (sigmask) 1393 sigprocmask(SIG_SETMASK, &sigsaved, NULL); 1394 1395 return ret; 1396 } 1397 1398 COMPAT_SYSCALL_DEFINE6(pselect6, int, n, compat_ulong_t __user *, inp, 1399 compat_ulong_t __user *, outp, compat_ulong_t __user *, exp, 1400 struct compat_timespec __user *, tsp, void __user *, sig) 1401 { 1402 compat_size_t sigsetsize = 0; 1403 compat_uptr_t up = 0; 1404 1405 if (sig) { 1406 if (!access_ok(VERIFY_READ, sig, 1407 sizeof(compat_uptr_t)+sizeof(compat_size_t)) || 1408 __get_user(up, (compat_uptr_t __user *)sig) || 1409 __get_user(sigsetsize, 1410 (compat_size_t __user *)(sig+sizeof(up)))) 1411 return -EFAULT; 1412 } 1413 return do_compat_pselect(n, inp, outp, exp, tsp, compat_ptr(up), 1414 sigsetsize); 1415 } 1416 1417 COMPAT_SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, 1418 unsigned int, nfds, struct compat_timespec __user *, tsp, 1419 const compat_sigset_t __user *, sigmask, compat_size_t, sigsetsize) 1420 { 1421 compat_sigset_t ss32; 1422 sigset_t ksigmask, sigsaved; 1423 struct compat_timespec ts; 1424 struct timespec end_time, *to = NULL; 1425 int ret; 1426 1427 if (tsp) { 1428 if (copy_from_user(&ts, tsp, sizeof(ts))) 1429 return -EFAULT; 1430 1431 to = &end_time; 1432 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) 1433 return -EINVAL; 1434 } 1435 1436 if (sigmask) { 1437 if (sigsetsize != sizeof(compat_sigset_t)) 1438 return -EINVAL; 1439 if (copy_from_user(&ss32, sigmask, sizeof(ss32))) 1440 return -EFAULT; 1441 sigset_from_compat(&ksigmask, &ss32); 1442 1443 sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP)); 1444 sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); 1445 } 1446 1447 ret = do_sys_poll(ufds, nfds, to); 1448 1449 /* We can restart this syscall, usually */ 1450 if (ret == -EINTR) { 1451 /* 1452 * Don't restore the signal mask yet. Let do_signal() deliver 1453 * the signal on the way back to userspace, before the signal 1454 * mask is restored. 1455 */ 1456 if (sigmask) { 1457 memcpy(¤t->saved_sigmask, &sigsaved, 1458 sizeof(sigsaved)); 1459 set_restore_sigmask(); 1460 } 1461 ret = -ERESTARTNOHAND; 1462 } else if (sigmask) 1463 sigprocmask(SIG_SETMASK, &sigsaved, NULL); 1464 1465 ret = compat_poll_select_copy_remaining(&end_time, tsp, 0, ret); 1466 1467 return ret; 1468 } 1469 #endif 1470