1// SPDX-License-Identifier: GPL-2.0 2/* 3 * This file contains the procedures for the handling of select and poll 4 * 5 * Created for Linux based loosely upon Mathius Lattner's minix 6 * patches by Peter MacDonald. Heavily edited by Linus. 7 * 8 * 4 February 1994 9 * COFF/ELF binary emulation. If the process has the STICKY_TIMEOUTS 10 * flag set in its personality we do *not* modify the given timeout 11 * parameter to reflect time remaining. 12 * 13 * 24 January 2000 14 * Changed sys_poll()/do_poll() to use PAGE_SIZE chunk-based allocation 15 * of fds to overcome nfds < 16390 descriptors limit (Tigran Aivazian). 16 */ 17 18#include <linux/compat.h> 19#include <linux/kernel.h> 20#include <linux/sched/signal.h> 21#include <linux/sched/rt.h> 22#include <linux/syscalls.h> 23#include <linux/export.h> 24#include <linux/slab.h> 25#include <linux/poll.h> 26#include <linux/personality.h> /* for STICKY_TIMEOUTS */ 27#include <linux/file.h> 28#include <linux/fdtable.h> 29#include <linux/fs.h> 30#include <linux/rcupdate.h> 31#include <linux/hrtimer.h> 32#include <linux/freezer.h> 33#include <net/busy_poll.h> 34#include <linux/vmalloc.h> 35 36#include <linux/uaccess.h> 37 38 39/* 40 * Estimate expected accuracy in ns from a timeval. 41 * 42 * After quite a bit of churning around, we've settled on 43 * a simple thing of taking 0.1% of the timeout as the 44 * slack, with a cap of 100 msec. 45 * "nice" tasks get a 0.5% slack instead. 46 * 47 * Consider this comment an open invitation to come up with even 48 * better solutions.. 49 */ 50 51#define MAX_SLACK (100 * NSEC_PER_MSEC) 52 53static long __estimate_accuracy(struct timespec64 *tv) 54{ 55 long slack; 56 int divfactor = 1000; 57 58 if (tv->tv_sec < 0) 59 return 0; 60 61 if (task_nice(current) > 0) 62 divfactor = divfactor / 5; 63 64 if (tv->tv_sec > MAX_SLACK / (NSEC_PER_SEC/divfactor)) 65 return MAX_SLACK; 66 67 slack = tv->tv_nsec / divfactor; 68 slack += tv->tv_sec * (NSEC_PER_SEC/divfactor); 69 70 if (slack > MAX_SLACK) 71 return MAX_SLACK; 72 73 return slack; 74} 75 76u64 select_estimate_accuracy(struct timespec64 *tv) 77{ 78 u64 ret; 79 struct timespec64 now; 80 81 /* 82 * Realtime tasks get a slack of 0 for obvious reasons. 83 */ 84 85 if (rt_task(current)) 86 return 0; 87 88 ktime_get_ts64(&now); 89 now = timespec64_sub(*tv, now); 90 ret = __estimate_accuracy(&now); 91 if (ret < current->timer_slack_ns) 92 return current->timer_slack_ns; 93 return ret; 94} 95 96 97 98struct poll_table_page { 99 struct poll_table_page * next; 100 struct poll_table_entry * entry; 101 struct poll_table_entry entries[]; 102}; 103 104#define POLL_TABLE_FULL(table) \ 105 ((unsigned long)((table)->entry+1) > PAGE_SIZE + (unsigned long)(table)) 106 107/* 108 * Ok, Peter made a complicated, but straightforward multiple_wait() function. 109 * I have rewritten this, taking some shortcuts: This code may not be easy to 110 * follow, but it should be free of race-conditions, and it's practical. If you 111 * understand what I'm doing here, then you understand how the linux 112 * sleep/wakeup mechanism works. 113 * 114 * Two very simple procedures, poll_wait() and poll_freewait() make all the 115 * work. poll_wait() is an inline-function defined in <linux/poll.h>, 116 * as all select/poll functions have to call it to add an entry to the 117 * poll table. 118 */ 119static void __pollwait(struct file *filp, wait_queue_head_t *wait_address, 120 poll_table *p); 121 122void poll_initwait(struct poll_wqueues *pwq) 123{ 124 init_poll_funcptr(&pwq->pt, __pollwait); 125 pwq->polling_task = current; 126 pwq->triggered = 0; 127 pwq->error = 0; 128 pwq->table = NULL; 129 pwq->inline_index = 0; 130} 131EXPORT_SYMBOL(poll_initwait); 132 133static void free_poll_entry(struct poll_table_entry *entry) 134{ 135 remove_wait_queue(entry->wait_address, &entry->wait); 136 fput(entry->filp); 137} 138 139void poll_freewait(struct poll_wqueues *pwq) 140{ 141 struct poll_table_page * p = pwq->table; 142 int i; 143 for (i = 0; i < pwq->inline_index; i++) 144 free_poll_entry(pwq->inline_entries + i); 145 while (p) { 146 struct poll_table_entry * entry; 147 struct poll_table_page *old; 148 149 entry = p->entry; 150 do { 151 entry--; 152 free_poll_entry(entry); 153 } while (entry > p->entries); 154 old = p; 155 p = p->next; 156 free_page((unsigned long) old); 157 } 158} 159EXPORT_SYMBOL(poll_freewait); 160 161static struct poll_table_entry *poll_get_entry(struct poll_wqueues *p) 162{ 163 struct poll_table_page *table = p->table; 164 165 if (p->inline_index < N_INLINE_POLL_ENTRIES) 166 return p->inline_entries + p->inline_index++; 167 168 if (!table || POLL_TABLE_FULL(table)) { 169 struct poll_table_page *new_table; 170 171 new_table = (struct poll_table_page *) __get_free_page(GFP_KERNEL); 172 if (!new_table) { 173 p->error = -ENOMEM; 174 return NULL; 175 } 176 new_table->entry = new_table->entries; 177 new_table->next = table; 178 p->table = new_table; 179 table = new_table; 180 } 181 182 return table->entry++; 183} 184 185static int __pollwake(wait_queue_entry_t *wait, unsigned mode, int sync, void *key) 186{ 187 struct poll_wqueues *pwq = wait->private; 188 DECLARE_WAITQUEUE(dummy_wait, pwq->polling_task); 189 190 /* 191 * Although this function is called under waitqueue lock, LOCK 192 * doesn't imply write barrier and the users expect write 193 * barrier semantics on wakeup functions. The following 194 * smp_wmb() is equivalent to smp_wmb() in try_to_wake_up() 195 * and is paired with smp_store_mb() in poll_schedule_timeout. 196 */ 197 smp_wmb(); 198 pwq->triggered = 1; 199 200 /* 201 * Perform the default wake up operation using a dummy 202 * waitqueue. 203 * 204 * TODO: This is hacky but there currently is no interface to 205 * pass in @sync. @sync is scheduled to be removed and once 206 * that happens, wake_up_process() can be used directly. 207 */ 208 return default_wake_function(&dummy_wait, mode, sync, key); 209} 210 211static int pollwake(wait_queue_entry_t *wait, unsigned mode, int sync, void *key) 212{ 213 struct poll_table_entry *entry; 214 215 entry = container_of(wait, struct poll_table_entry, wait); 216 if (key && !(key_to_poll(key) & entry->key)) 217 return 0; 218 return __pollwake(wait, mode, sync, key); 219} 220 221/* Add a new entry */ 222static void __pollwait(struct file *filp, wait_queue_head_t *wait_address, 223 poll_table *p) 224{ 225 struct poll_wqueues *pwq = container_of(p, struct poll_wqueues, pt); 226 struct poll_table_entry *entry = poll_get_entry(pwq); 227 if (!entry) 228 return; 229 entry->filp = get_file(filp); 230 entry->wait_address = wait_address; 231 entry->key = p->_key; 232 init_waitqueue_func_entry(&entry->wait, pollwake); 233 entry->wait.private = pwq; 234 add_wait_queue(wait_address, &entry->wait); 235} 236 237static int poll_schedule_timeout(struct poll_wqueues *pwq, int state, 238 ktime_t *expires, unsigned long slack) 239{ 240 int rc = -EINTR; 241 242 set_current_state(state); 243 if (!pwq->triggered) 244 rc = schedule_hrtimeout_range(expires, slack, HRTIMER_MODE_ABS); 245 __set_current_state(TASK_RUNNING); 246 247 /* 248 * Prepare for the next iteration. 249 * 250 * The following smp_store_mb() serves two purposes. First, it's 251 * the counterpart rmb of the wmb in pollwake() such that data 252 * written before wake up is always visible after wake up. 253 * Second, the full barrier guarantees that triggered clearing 254 * doesn't pass event check of the next iteration. Note that 255 * this problem doesn't exist for the first iteration as 256 * add_wait_queue() has full barrier semantics. 257 */ 258 smp_store_mb(pwq->triggered, 0); 259 260 return rc; 261} 262 263/** 264 * poll_select_set_timeout - helper function to setup the timeout value 265 * @to: pointer to timespec64 variable for the final timeout 266 * @sec: seconds (from user space) 267 * @nsec: nanoseconds (from user space) 268 * 269 * Note, we do not use a timespec for the user space value here, That 270 * way we can use the function for timeval and compat interfaces as well. 271 * 272 * Returns -EINVAL if sec/nsec are not normalized. Otherwise 0. 273 */ 274int poll_select_set_timeout(struct timespec64 *to, time64_t sec, long nsec) 275{ 276 struct timespec64 ts = {.tv_sec = sec, .tv_nsec = nsec}; 277 278 if (!timespec64_valid(&ts)) 279 return -EINVAL; 280 281 /* Optimize for the zero timeout value here */ 282 if (!sec && !nsec) { 283 to->tv_sec = to->tv_nsec = 0; 284 } else { 285 ktime_get_ts64(to); 286 *to = timespec64_add_safe(*to, ts); 287 } 288 return 0; 289} 290 291enum poll_time_type { 292 PT_TIMEVAL = 0, 293 PT_OLD_TIMEVAL = 1, 294 PT_TIMESPEC = 2, 295 PT_OLD_TIMESPEC = 3, 296}; 297 298static int poll_select_finish(struct timespec64 *end_time, 299 void __user *p, 300 enum poll_time_type pt_type, int ret) 301{ 302 struct timespec64 rts; 303 304 restore_saved_sigmask_unless(ret == -ERESTARTNOHAND); 305 306 if (!p) 307 return ret; 308 309 if (current->personality & STICKY_TIMEOUTS) 310 goto sticky; 311 312 /* No update for zero timeout */ 313 if (!end_time->tv_sec && !end_time->tv_nsec) 314 return ret; 315 316 ktime_get_ts64(&rts); 317 rts = timespec64_sub(*end_time, rts); 318 if (rts.tv_sec < 0) 319 rts.tv_sec = rts.tv_nsec = 0; 320 321 322 switch (pt_type) { 323 case PT_TIMEVAL: 324 { 325 struct __kernel_old_timeval rtv; 326 327 if (sizeof(rtv) > sizeof(rtv.tv_sec) + sizeof(rtv.tv_usec)) 328 memset(&rtv, 0, sizeof(rtv)); 329 rtv.tv_sec = rts.tv_sec; 330 rtv.tv_usec = rts.tv_nsec / NSEC_PER_USEC; 331 if (!copy_to_user(p, &rtv, sizeof(rtv))) 332 return ret; 333 } 334 break; 335 case PT_OLD_TIMEVAL: 336 { 337 struct old_timeval32 rtv; 338 339 rtv.tv_sec = rts.tv_sec; 340 rtv.tv_usec = rts.tv_nsec / NSEC_PER_USEC; 341 if (!copy_to_user(p, &rtv, sizeof(rtv))) 342 return ret; 343 } 344 break; 345 case PT_TIMESPEC: 346 if (!put_timespec64(&rts, p)) 347 return ret; 348 break; 349 case PT_OLD_TIMESPEC: 350 if (!put_old_timespec32(&rts, p)) 351 return ret; 352 break; 353 default: 354 BUG(); 355 } 356 /* 357 * If an application puts its timeval in read-only memory, we 358 * don't want the Linux-specific update to the timeval to 359 * cause a fault after the select has completed 360 * successfully. However, because we're not updating the 361 * timeval, we can't restart the system call. 362 */ 363 364sticky: 365 if (ret == -ERESTARTNOHAND) 366 ret = -EINTR; 367 return ret; 368} 369 370/* 371 * Scalable version of the fd_set. 372 */ 373 374typedef struct { 375 unsigned long *in, *out, *ex; 376 unsigned long *res_in, *res_out, *res_ex; 377} fd_set_bits; 378 379/* 380 * How many longwords for "nr" bits? 381 */ 382#define FDS_BITPERLONG (8*sizeof(long)) 383#define FDS_LONGS(nr) (((nr)+FDS_BITPERLONG-1)/FDS_BITPERLONG) 384#define FDS_BYTES(nr) (FDS_LONGS(nr)*sizeof(long)) 385 386/* 387 * Use "unsigned long" accesses to let user-mode fd_set's be long-aligned. 388 */ 389static inline 390int get_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset) 391{ 392 nr = FDS_BYTES(nr); 393 if (ufdset) 394 return copy_from_user(fdset, ufdset, nr) ? -EFAULT : 0; 395 396 memset(fdset, 0, nr); 397 return 0; 398} 399 400static inline unsigned long __must_check 401set_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset) 402{ 403 if (ufdset) 404 return __copy_to_user(ufdset, fdset, FDS_BYTES(nr)); 405 return 0; 406} 407 408static inline 409void zero_fd_set(unsigned long nr, unsigned long *fdset) 410{ 411 memset(fdset, 0, FDS_BYTES(nr)); 412} 413 414#define FDS_IN(fds, n) (fds->in + n) 415#define FDS_OUT(fds, n) (fds->out + n) 416#define FDS_EX(fds, n) (fds->ex + n) 417 418#define BITS(fds, n) (*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n)) 419 420static int max_select_fd(unsigned long n, fd_set_bits *fds) 421{ 422 unsigned long *open_fds; 423 unsigned long set; 424 int max; 425 struct fdtable *fdt; 426 427 /* handle last in-complete long-word first */ 428 set = ~(~0UL << (n & (BITS_PER_LONG-1))); 429 n /= BITS_PER_LONG; 430 fdt = files_fdtable(current->files); 431 open_fds = fdt->open_fds + n; 432 max = 0; 433 if (set) { 434 set &= BITS(fds, n); 435 if (set) { 436 if (!(set & ~*open_fds)) 437 goto get_max; 438 return -EBADF; 439 } 440 } 441 while (n) { 442 open_fds--; 443 n--; 444 set = BITS(fds, n); 445 if (!set) 446 continue; 447 if (set & ~*open_fds) 448 return -EBADF; 449 if (max) 450 continue; 451get_max: 452 do { 453 max++; 454 set >>= 1; 455 } while (set); 456 max += n * BITS_PER_LONG; 457 } 458 459 return max; 460} 461 462#define POLLIN_SET (EPOLLRDNORM | EPOLLRDBAND | EPOLLIN | EPOLLHUP | EPOLLERR |\ 463 EPOLLNVAL) 464#define POLLOUT_SET (EPOLLWRBAND | EPOLLWRNORM | EPOLLOUT | EPOLLERR |\ 465 EPOLLNVAL) 466#define POLLEX_SET (EPOLLPRI | EPOLLNVAL) 467 468static inline void wait_key_set(poll_table *wait, unsigned long in, 469 unsigned long out, unsigned long bit, 470 __poll_t ll_flag) 471{ 472 wait->_key = POLLEX_SET | ll_flag; 473 if (in & bit) 474 wait->_key |= POLLIN_SET; 475 if (out & bit) 476 wait->_key |= POLLOUT_SET; 477} 478 479static noinline_for_stack int do_select(int n, fd_set_bits *fds, struct timespec64 *end_time) 480{ 481 ktime_t expire, *to = NULL; 482 struct poll_wqueues table; 483 poll_table *wait; 484 int retval, i, timed_out = 0; 485 u64 slack = 0; 486 __poll_t busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0; 487 unsigned long busy_start = 0; 488 489 rcu_read_lock(); 490 retval = max_select_fd(n, fds); 491 rcu_read_unlock(); 492 493 if (retval < 0) 494 return retval; 495 n = retval; 496 497 poll_initwait(&table); 498 wait = &table.pt; 499 if (end_time && !end_time->tv_sec && !end_time->tv_nsec) { 500 wait->_qproc = NULL; 501 timed_out = 1; 502 } 503 504 if (end_time && !timed_out) 505 slack = select_estimate_accuracy(end_time); 506 507 retval = 0; 508 for (;;) { 509 unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp; 510 bool can_busy_loop = false; 511 512 inp = fds->in; outp = fds->out; exp = fds->ex; 513 rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex; 514 515 for (i = 0; i < n; ++rinp, ++routp, ++rexp) { 516 unsigned long in, out, ex, all_bits, bit = 1, j; 517 unsigned long res_in = 0, res_out = 0, res_ex = 0; 518 __poll_t mask; 519 520 in = *inp++; out = *outp++; ex = *exp++; 521 all_bits = in | out | ex; 522 if (all_bits == 0) { 523 i += BITS_PER_LONG; 524 continue; 525 } 526 527 for (j = 0; j < BITS_PER_LONG; ++j, ++i, bit <<= 1) { 528 struct fd f; 529 if (i >= n) 530 break; 531 if (!(bit & all_bits)) 532 continue; 533 mask = EPOLLNVAL; 534 f = fdget(i); 535 if (f.file) { 536 wait_key_set(wait, in, out, bit, 537 busy_flag); 538 mask = vfs_poll(f.file, wait); 539 540 fdput(f); 541 } 542 if ((mask & POLLIN_SET) && (in & bit)) { 543 res_in |= bit; 544 retval++; 545 wait->_qproc = NULL; 546 } 547 if ((mask & POLLOUT_SET) && (out & bit)) { 548 res_out |= bit; 549 retval++; 550 wait->_qproc = NULL; 551 } 552 if ((mask & POLLEX_SET) && (ex & bit)) { 553 res_ex |= bit; 554 retval++; 555 wait->_qproc = NULL; 556 } 557 /* got something, stop busy polling */ 558 if (retval) { 559 can_busy_loop = false; 560 busy_flag = 0; 561 562 /* 563 * only remember a returned 564 * POLL_BUSY_LOOP if we asked for it 565 */ 566 } else if (busy_flag & mask) 567 can_busy_loop = true; 568 569 } 570 if (res_in) 571 *rinp = res_in; 572 if (res_out) 573 *routp = res_out; 574 if (res_ex) 575 *rexp = res_ex; 576 cond_resched(); 577 } 578 wait->_qproc = NULL; 579 if (retval || timed_out || signal_pending(current)) 580 break; 581 if (table.error) { 582 retval = table.error; 583 break; 584 } 585 586 /* only if found POLL_BUSY_LOOP sockets && not out of time */ 587 if (can_busy_loop && !need_resched()) { 588 if (!busy_start) { 589 busy_start = busy_loop_current_time(); 590 continue; 591 } 592 if (!busy_loop_timeout(busy_start)) 593 continue; 594 } 595 busy_flag = 0; 596 597 /* 598 * If this is the first loop and we have a timeout 599 * given, then we convert to ktime_t and set the to 600 * pointer to the expiry value. 601 */ 602 if (end_time && !to) { 603 expire = timespec64_to_ktime(*end_time); 604 to = &expire; 605 } 606 607 if (!poll_schedule_timeout(&table, TASK_INTERRUPTIBLE, 608 to, slack)) 609 timed_out = 1; 610 } 611 612 poll_freewait(&table); 613 614 return retval; 615} 616 617/* 618 * We can actually return ERESTARTSYS instead of EINTR, but I'd 619 * like to be certain this leads to no problems. So I return 620 * EINTR just for safety. 621 * 622 * Update: ERESTARTSYS breaks at least the xview clock binary, so 623 * I'm trying ERESTARTNOHAND which restart only when you want to. 624 */ 625int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp, 626 fd_set __user *exp, struct timespec64 *end_time) 627{ 628 fd_set_bits fds; 629 void *bits; 630 int ret, max_fds; 631 size_t size, alloc_size; 632 struct fdtable *fdt; 633 /* Allocate small arguments on the stack to save memory and be faster */ 634 long stack_fds[SELECT_STACK_ALLOC/sizeof(long)]; 635 636 ret = -EINVAL; 637 if (n < 0) 638 goto out_nofds; 639 640 /* max_fds can increase, so grab it once to avoid race */ 641 rcu_read_lock(); 642 fdt = files_fdtable(current->files); 643 max_fds = fdt->max_fds; 644 rcu_read_unlock(); 645 if (n > max_fds) 646 n = max_fds; 647 648 /* 649 * We need 6 bitmaps (in/out/ex for both incoming and outgoing), 650 * since we used fdset we need to allocate memory in units of 651 * long-words. 652 */ 653 size = FDS_BYTES(n); 654 bits = stack_fds; 655 if (size > sizeof(stack_fds) / 6) { 656 /* Not enough space in on-stack array; must use kmalloc */ 657 ret = -ENOMEM; 658 if (size > (SIZE_MAX / 6)) 659 goto out_nofds; 660 661 alloc_size = 6 * size; 662 bits = kvmalloc(alloc_size, GFP_KERNEL); 663 if (!bits) 664 goto out_nofds; 665 } 666 fds.in = bits; 667 fds.out = bits + size; 668 fds.ex = bits + 2*size; 669 fds.res_in = bits + 3*size; 670 fds.res_out = bits + 4*size; 671 fds.res_ex = bits + 5*size; 672 673 if ((ret = get_fd_set(n, inp, fds.in)) || 674 (ret = get_fd_set(n, outp, fds.out)) || 675 (ret = get_fd_set(n, exp, fds.ex))) 676 goto out; 677 zero_fd_set(n, fds.res_in); 678 zero_fd_set(n, fds.res_out); 679 zero_fd_set(n, fds.res_ex); 680 681 ret = do_select(n, &fds, end_time); 682 683 if (ret < 0) 684 goto out; 685 if (!ret) { 686 ret = -ERESTARTNOHAND; 687 if (signal_pending(current)) 688 goto out; 689 ret = 0; 690 } 691 692 if (set_fd_set(n, inp, fds.res_in) || 693 set_fd_set(n, outp, fds.res_out) || 694 set_fd_set(n, exp, fds.res_ex)) 695 ret = -EFAULT; 696 697out: 698 if (bits != stack_fds) 699 kvfree(bits); 700out_nofds: 701 return ret; 702} 703 704static int kern_select(int n, fd_set __user *inp, fd_set __user *outp, 705 fd_set __user *exp, struct __kernel_old_timeval __user *tvp) 706{ 707 struct timespec64 end_time, *to = NULL; 708 struct __kernel_old_timeval tv; 709 int ret; 710 711 if (tvp) { 712 if (copy_from_user(&tv, tvp, sizeof(tv))) 713 return -EFAULT; 714 715 to = &end_time; 716 if (poll_select_set_timeout(to, 717 tv.tv_sec + (tv.tv_usec / USEC_PER_SEC), 718 (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC)) 719 return -EINVAL; 720 } 721 722 ret = core_sys_select(n, inp, outp, exp, to); 723 return poll_select_finish(&end_time, tvp, PT_TIMEVAL, ret); 724} 725 726SYSCALL_DEFINE5(select, int, n, fd_set __user *, inp, fd_set __user *, outp, 727 fd_set __user *, exp, struct __kernel_old_timeval __user *, tvp) 728{ 729 return kern_select(n, inp, outp, exp, tvp); 730} 731 732static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp, 733 fd_set __user *exp, void __user *tsp, 734 const sigset_t __user *sigmask, size_t sigsetsize, 735 enum poll_time_type type) 736{ 737 struct timespec64 ts, end_time, *to = NULL; 738 int ret; 739 740 if (tsp) { 741 switch (type) { 742 case PT_TIMESPEC: 743 if (get_timespec64(&ts, tsp)) 744 return -EFAULT; 745 break; 746 case PT_OLD_TIMESPEC: 747 if (get_old_timespec32(&ts, tsp)) 748 return -EFAULT; 749 break; 750 default: 751 BUG(); 752 } 753 754 to = &end_time; 755 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) 756 return -EINVAL; 757 } 758 759 ret = set_user_sigmask(sigmask, sigsetsize); 760 if (ret) 761 return ret; 762 763 ret = core_sys_select(n, inp, outp, exp, to); 764 return poll_select_finish(&end_time, tsp, type, ret); 765} 766 767/* 768 * Most architectures can't handle 7-argument syscalls. So we provide a 769 * 6-argument version where the sixth argument is a pointer to a structure 770 * which has a pointer to the sigset_t itself followed by a size_t containing 771 * the sigset size. 772 */ 773struct sigset_argpack { 774 sigset_t __user *p; 775 size_t size; 776}; 777 778static inline int get_sigset_argpack(struct sigset_argpack *to, 779 struct sigset_argpack __user *from) 780{ 781 // the path is hot enough for overhead of copy_from_user() to matter 782 if (from) { 783 if (!user_read_access_begin(from, sizeof(*from))) 784 return -EFAULT; 785 unsafe_get_user(to->p, &from->p, Efault); 786 unsafe_get_user(to->size, &from->size, Efault); 787 user_read_access_end(); 788 } 789 return 0; 790Efault: 791 user_access_end(); 792 return -EFAULT; 793} 794 795SYSCALL_DEFINE6(pselect6, int, n, fd_set __user *, inp, fd_set __user *, outp, 796 fd_set __user *, exp, struct __kernel_timespec __user *, tsp, 797 void __user *, sig) 798{ 799 struct sigset_argpack x = {NULL, 0}; 800 801 if (get_sigset_argpack(&x, sig)) 802 return -EFAULT; 803 804 return do_pselect(n, inp, outp, exp, tsp, x.p, x.size, PT_TIMESPEC); 805} 806 807#if defined(CONFIG_COMPAT_32BIT_TIME) && !defined(CONFIG_64BIT) 808 809SYSCALL_DEFINE6(pselect6_time32, int, n, fd_set __user *, inp, fd_set __user *, outp, 810 fd_set __user *, exp, struct old_timespec32 __user *, tsp, 811 void __user *, sig) 812{ 813 struct sigset_argpack x = {NULL, 0}; 814 815 if (get_sigset_argpack(&x, sig)) 816 return -EFAULT; 817 818 return do_pselect(n, inp, outp, exp, tsp, x.p, x.size, PT_OLD_TIMESPEC); 819} 820 821#endif 822 823#ifdef __ARCH_WANT_SYS_OLD_SELECT 824struct sel_arg_struct { 825 unsigned long n; 826 fd_set __user *inp, *outp, *exp; 827 struct __kernel_old_timeval __user *tvp; 828}; 829 830SYSCALL_DEFINE1(old_select, struct sel_arg_struct __user *, arg) 831{ 832 struct sel_arg_struct a; 833 834 if (copy_from_user(&a, arg, sizeof(a))) 835 return -EFAULT; 836 return kern_select(a.n, a.inp, a.outp, a.exp, a.tvp); 837} 838#endif 839 840struct poll_list { 841 struct poll_list *next; 842 unsigned int len; 843 struct pollfd entries[]; 844}; 845 846#define POLLFD_PER_PAGE ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd)) 847 848/* 849 * Fish for pollable events on the pollfd->fd file descriptor. We're only 850 * interested in events matching the pollfd->events mask, and the result 851 * matching that mask is both recorded in pollfd->revents and returned. The 852 * pwait poll_table will be used by the fd-provided poll handler for waiting, 853 * if pwait->_qproc is non-NULL. 854 */ 855static inline __poll_t do_pollfd(struct pollfd *pollfd, poll_table *pwait, 856 bool *can_busy_poll, 857 __poll_t busy_flag) 858{ 859 int fd = pollfd->fd; 860 __poll_t mask = 0, filter; 861 struct fd f; 862 863 if (fd < 0) 864 goto out; 865 mask = EPOLLNVAL; 866 f = fdget(fd); 867 if (!f.file) 868 goto out; 869 870 /* userland u16 ->events contains POLL... bitmap */ 871 filter = demangle_poll(pollfd->events) | EPOLLERR | EPOLLHUP; 872 pwait->_key = filter | busy_flag; 873 mask = vfs_poll(f.file, pwait); 874 if (mask & busy_flag) 875 *can_busy_poll = true; 876 mask &= filter; /* Mask out unneeded events. */ 877 fdput(f); 878 879out: 880 /* ... and so does ->revents */ 881 pollfd->revents = mangle_poll(mask); 882 return mask; 883} 884 885static int do_poll(struct poll_list *list, struct poll_wqueues *wait, 886 struct timespec64 *end_time) 887{ 888 poll_table* pt = &wait->pt; 889 ktime_t expire, *to = NULL; 890 int timed_out = 0, count = 0; 891 u64 slack = 0; 892 __poll_t busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0; 893 unsigned long busy_start = 0; 894 895 /* Optimise the no-wait case */ 896 if (end_time && !end_time->tv_sec && !end_time->tv_nsec) { 897 pt->_qproc = NULL; 898 timed_out = 1; 899 } 900 901 if (end_time && !timed_out) 902 slack = select_estimate_accuracy(end_time); 903 904 for (;;) { 905 struct poll_list *walk; 906 bool can_busy_loop = false; 907 908 for (walk = list; walk != NULL; walk = walk->next) { 909 struct pollfd * pfd, * pfd_end; 910 911 pfd = walk->entries; 912 pfd_end = pfd + walk->len; 913 for (; pfd != pfd_end; pfd++) { 914 /* 915 * Fish for events. If we found one, record it 916 * and kill poll_table->_qproc, so we don't 917 * needlessly register any other waiters after 918 * this. They'll get immediately deregistered 919 * when we break out and return. 920 */ 921 if (do_pollfd(pfd, pt, &can_busy_loop, 922 busy_flag)) { 923 count++; 924 pt->_qproc = NULL; 925 /* found something, stop busy polling */ 926 busy_flag = 0; 927 can_busy_loop = false; 928 } 929 } 930 } 931 /* 932 * All waiters have already been registered, so don't provide 933 * a poll_table->_qproc to them on the next loop iteration. 934 */ 935 pt->_qproc = NULL; 936 if (!count) { 937 count = wait->error; 938 if (signal_pending(current)) 939 count = -ERESTARTNOHAND; 940 } 941 if (count || timed_out) 942 break; 943 944 /* only if found POLL_BUSY_LOOP sockets && not out of time */ 945 if (can_busy_loop && !need_resched()) { 946 if (!busy_start) { 947 busy_start = busy_loop_current_time(); 948 continue; 949 } 950 if (!busy_loop_timeout(busy_start)) 951 continue; 952 } 953 busy_flag = 0; 954 955 /* 956 * If this is the first loop and we have a timeout 957 * given, then we convert to ktime_t and set the to 958 * pointer to the expiry value. 959 */ 960 if (end_time && !to) { 961 expire = timespec64_to_ktime(*end_time); 962 to = &expire; 963 } 964 965 if (!poll_schedule_timeout(wait, TASK_INTERRUPTIBLE, to, slack)) 966 timed_out = 1; 967 } 968 return count; 969} 970 971#define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \ 972 sizeof(struct pollfd)) 973 974static int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds, 975 struct timespec64 *end_time) 976{ 977 struct poll_wqueues table; 978 int err = -EFAULT, fdcount; 979 /* Allocate small arguments on the stack to save memory and be 980 faster - use long to make sure the buffer is aligned properly 981 on 64 bit archs to avoid unaligned access */ 982 long stack_pps[POLL_STACK_ALLOC/sizeof(long)]; 983 struct poll_list *const head = (struct poll_list *)stack_pps; 984 struct poll_list *walk = head; 985 unsigned int todo = nfds; 986 unsigned int len; 987 988 if (nfds > rlimit(RLIMIT_NOFILE)) 989 return -EINVAL; 990 991 len = min_t(unsigned int, nfds, N_STACK_PPS); 992 for (;;) { 993 walk->next = NULL; 994 walk->len = len; 995 if (!len) 996 break; 997 998 if (copy_from_user(walk->entries, ufds + nfds-todo, 999 sizeof(struct pollfd) * walk->len)) 1000 goto out_fds; 1001 1002 if (walk->len >= todo) 1003 break; 1004 todo -= walk->len; 1005 1006 len = min(todo, POLLFD_PER_PAGE); 1007 walk = walk->next = kmalloc(struct_size(walk, entries, len), 1008 GFP_KERNEL); 1009 if (!walk) { 1010 err = -ENOMEM; 1011 goto out_fds; 1012 } 1013 } 1014 1015 poll_initwait(&table); 1016 fdcount = do_poll(head, &table, end_time); 1017 poll_freewait(&table); 1018 1019 if (!user_write_access_begin(ufds, nfds * sizeof(*ufds))) 1020 goto out_fds; 1021 1022 for (walk = head; walk; walk = walk->next) { 1023 struct pollfd *fds = walk->entries; 1024 unsigned int j; 1025 1026 for (j = walk->len; j; fds++, ufds++, j--) 1027 unsafe_put_user(fds->revents, &ufds->revents, Efault); 1028 } 1029 user_write_access_end(); 1030 1031 err = fdcount; 1032out_fds: 1033 walk = head->next; 1034 while (walk) { 1035 struct poll_list *pos = walk; 1036 walk = walk->next; 1037 kfree(pos); 1038 } 1039 1040 return err; 1041 1042Efault: 1043 user_write_access_end(); 1044 err = -EFAULT; 1045 goto out_fds; 1046} 1047 1048static long do_restart_poll(struct restart_block *restart_block) 1049{ 1050 struct pollfd __user *ufds = restart_block->poll.ufds; 1051 int nfds = restart_block->poll.nfds; 1052 struct timespec64 *to = NULL, end_time; 1053 int ret; 1054 1055 if (restart_block->poll.has_timeout) { 1056 end_time.tv_sec = restart_block->poll.tv_sec; 1057 end_time.tv_nsec = restart_block->poll.tv_nsec; 1058 to = &end_time; 1059 } 1060 1061 ret = do_sys_poll(ufds, nfds, to); 1062 1063 if (ret == -ERESTARTNOHAND) 1064 ret = set_restart_fn(restart_block, do_restart_poll); 1065 1066 return ret; 1067} 1068 1069SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds, 1070 int, timeout_msecs) 1071{ 1072 struct timespec64 end_time, *to = NULL; 1073 int ret; 1074 1075 if (timeout_msecs >= 0) { 1076 to = &end_time; 1077 poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC, 1078 NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC)); 1079 } 1080 1081 ret = do_sys_poll(ufds, nfds, to); 1082 1083 if (ret == -ERESTARTNOHAND) { 1084 struct restart_block *restart_block; 1085 1086 restart_block = ¤t->restart_block; 1087 restart_block->poll.ufds = ufds; 1088 restart_block->poll.nfds = nfds; 1089 1090 if (timeout_msecs >= 0) { 1091 restart_block->poll.tv_sec = end_time.tv_sec; 1092 restart_block->poll.tv_nsec = end_time.tv_nsec; 1093 restart_block->poll.has_timeout = 1; 1094 } else 1095 restart_block->poll.has_timeout = 0; 1096 1097 ret = set_restart_fn(restart_block, do_restart_poll); 1098 } 1099 return ret; 1100} 1101 1102SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds, 1103 struct __kernel_timespec __user *, tsp, const sigset_t __user *, sigmask, 1104 size_t, sigsetsize) 1105{ 1106 struct timespec64 ts, end_time, *to = NULL; 1107 int ret; 1108 1109 if (tsp) { 1110 if (get_timespec64(&ts, tsp)) 1111 return -EFAULT; 1112 1113 to = &end_time; 1114 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) 1115 return -EINVAL; 1116 } 1117 1118 ret = set_user_sigmask(sigmask, sigsetsize); 1119 if (ret) 1120 return ret; 1121 1122 ret = do_sys_poll(ufds, nfds, to); 1123 return poll_select_finish(&end_time, tsp, PT_TIMESPEC, ret); 1124} 1125 1126#if defined(CONFIG_COMPAT_32BIT_TIME) && !defined(CONFIG_64BIT) 1127 1128SYSCALL_DEFINE5(ppoll_time32, struct pollfd __user *, ufds, unsigned int, nfds, 1129 struct old_timespec32 __user *, tsp, const sigset_t __user *, sigmask, 1130 size_t, sigsetsize) 1131{ 1132 struct timespec64 ts, end_time, *to = NULL; 1133 int ret; 1134 1135 if (tsp) { 1136 if (get_old_timespec32(&ts, tsp)) 1137 return -EFAULT; 1138 1139 to = &end_time; 1140 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) 1141 return -EINVAL; 1142 } 1143 1144 ret = set_user_sigmask(sigmask, sigsetsize); 1145 if (ret) 1146 return ret; 1147 1148 ret = do_sys_poll(ufds, nfds, to); 1149 return poll_select_finish(&end_time, tsp, PT_OLD_TIMESPEC, ret); 1150} 1151#endif 1152 1153#ifdef CONFIG_COMPAT 1154#define __COMPAT_NFDBITS (8 * sizeof(compat_ulong_t)) 1155 1156/* 1157 * Ooo, nasty. We need here to frob 32-bit unsigned longs to 1158 * 64-bit unsigned longs. 1159 */ 1160static 1161int compat_get_fd_set(unsigned long nr, compat_ulong_t __user *ufdset, 1162 unsigned long *fdset) 1163{ 1164 if (ufdset) { 1165 return compat_get_bitmap(fdset, ufdset, nr); 1166 } else { 1167 zero_fd_set(nr, fdset); 1168 return 0; 1169 } 1170} 1171 1172static 1173int compat_set_fd_set(unsigned long nr, compat_ulong_t __user *ufdset, 1174 unsigned long *fdset) 1175{ 1176 if (!ufdset) 1177 return 0; 1178 return compat_put_bitmap(ufdset, fdset, nr); 1179} 1180 1181 1182/* 1183 * This is a virtual copy of sys_select from fs/select.c and probably 1184 * should be compared to it from time to time 1185 */ 1186 1187/* 1188 * We can actually return ERESTARTSYS instead of EINTR, but I'd 1189 * like to be certain this leads to no problems. So I return 1190 * EINTR just for safety. 1191 * 1192 * Update: ERESTARTSYS breaks at least the xview clock binary, so 1193 * I'm trying ERESTARTNOHAND which restart only when you want to. 1194 */ 1195static int compat_core_sys_select(int n, compat_ulong_t __user *inp, 1196 compat_ulong_t __user *outp, compat_ulong_t __user *exp, 1197 struct timespec64 *end_time) 1198{ 1199 fd_set_bits fds; 1200 void *bits; 1201 int size, max_fds, ret = -EINVAL; 1202 struct fdtable *fdt; 1203 long stack_fds[SELECT_STACK_ALLOC/sizeof(long)]; 1204 1205 if (n < 0) 1206 goto out_nofds; 1207 1208 /* max_fds can increase, so grab it once to avoid race */ 1209 rcu_read_lock(); 1210 fdt = files_fdtable(current->files); 1211 max_fds = fdt->max_fds; 1212 rcu_read_unlock(); 1213 if (n > max_fds) 1214 n = max_fds; 1215 1216 /* 1217 * We need 6 bitmaps (in/out/ex for both incoming and outgoing), 1218 * since we used fdset we need to allocate memory in units of 1219 * long-words. 1220 */ 1221 size = FDS_BYTES(n); 1222 bits = stack_fds; 1223 if (size > sizeof(stack_fds) / 6) { 1224 bits = kmalloc_array(6, size, GFP_KERNEL); 1225 ret = -ENOMEM; 1226 if (!bits) 1227 goto out_nofds; 1228 } 1229 fds.in = (unsigned long *) bits; 1230 fds.out = (unsigned long *) (bits + size); 1231 fds.ex = (unsigned long *) (bits + 2*size); 1232 fds.res_in = (unsigned long *) (bits + 3*size); 1233 fds.res_out = (unsigned long *) (bits + 4*size); 1234 fds.res_ex = (unsigned long *) (bits + 5*size); 1235 1236 if ((ret = compat_get_fd_set(n, inp, fds.in)) || 1237 (ret = compat_get_fd_set(n, outp, fds.out)) || 1238 (ret = compat_get_fd_set(n, exp, fds.ex))) 1239 goto out; 1240 zero_fd_set(n, fds.res_in); 1241 zero_fd_set(n, fds.res_out); 1242 zero_fd_set(n, fds.res_ex); 1243 1244 ret = do_select(n, &fds, end_time); 1245 1246 if (ret < 0) 1247 goto out; 1248 if (!ret) { 1249 ret = -ERESTARTNOHAND; 1250 if (signal_pending(current)) 1251 goto out; 1252 ret = 0; 1253 } 1254 1255 if (compat_set_fd_set(n, inp, fds.res_in) || 1256 compat_set_fd_set(n, outp, fds.res_out) || 1257 compat_set_fd_set(n, exp, fds.res_ex)) 1258 ret = -EFAULT; 1259out: 1260 if (bits != stack_fds) 1261 kfree(bits); 1262out_nofds: 1263 return ret; 1264} 1265 1266static int do_compat_select(int n, compat_ulong_t __user *inp, 1267 compat_ulong_t __user *outp, compat_ulong_t __user *exp, 1268 struct old_timeval32 __user *tvp) 1269{ 1270 struct timespec64 end_time, *to = NULL; 1271 struct old_timeval32 tv; 1272 int ret; 1273 1274 if (tvp) { 1275 if (copy_from_user(&tv, tvp, sizeof(tv))) 1276 return -EFAULT; 1277 1278 to = &end_time; 1279 if (poll_select_set_timeout(to, 1280 tv.tv_sec + (tv.tv_usec / USEC_PER_SEC), 1281 (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC)) 1282 return -EINVAL; 1283 } 1284 1285 ret = compat_core_sys_select(n, inp, outp, exp, to); 1286 return poll_select_finish(&end_time, tvp, PT_OLD_TIMEVAL, ret); 1287} 1288 1289COMPAT_SYSCALL_DEFINE5(select, int, n, compat_ulong_t __user *, inp, 1290 compat_ulong_t __user *, outp, compat_ulong_t __user *, exp, 1291 struct old_timeval32 __user *, tvp) 1292{ 1293 return do_compat_select(n, inp, outp, exp, tvp); 1294} 1295 1296struct compat_sel_arg_struct { 1297 compat_ulong_t n; 1298 compat_uptr_t inp; 1299 compat_uptr_t outp; 1300 compat_uptr_t exp; 1301 compat_uptr_t tvp; 1302}; 1303 1304COMPAT_SYSCALL_DEFINE1(old_select, struct compat_sel_arg_struct __user *, arg) 1305{ 1306 struct compat_sel_arg_struct a; 1307 1308 if (copy_from_user(&a, arg, sizeof(a))) 1309 return -EFAULT; 1310 return do_compat_select(a.n, compat_ptr(a.inp), compat_ptr(a.outp), 1311 compat_ptr(a.exp), compat_ptr(a.tvp)); 1312} 1313 1314static long do_compat_pselect(int n, compat_ulong_t __user *inp, 1315 compat_ulong_t __user *outp, compat_ulong_t __user *exp, 1316 void __user *tsp, compat_sigset_t __user *sigmask, 1317 compat_size_t sigsetsize, enum poll_time_type type) 1318{ 1319 struct timespec64 ts, end_time, *to = NULL; 1320 int ret; 1321 1322 if (tsp) { 1323 switch (type) { 1324 case PT_OLD_TIMESPEC: 1325 if (get_old_timespec32(&ts, tsp)) 1326 return -EFAULT; 1327 break; 1328 case PT_TIMESPEC: 1329 if (get_timespec64(&ts, tsp)) 1330 return -EFAULT; 1331 break; 1332 default: 1333 BUG(); 1334 } 1335 1336 to = &end_time; 1337 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) 1338 return -EINVAL; 1339 } 1340 1341 ret = set_compat_user_sigmask(sigmask, sigsetsize); 1342 if (ret) 1343 return ret; 1344 1345 ret = compat_core_sys_select(n, inp, outp, exp, to); 1346 return poll_select_finish(&end_time, tsp, type, ret); 1347} 1348 1349struct compat_sigset_argpack { 1350 compat_uptr_t p; 1351 compat_size_t size; 1352}; 1353static inline int get_compat_sigset_argpack(struct compat_sigset_argpack *to, 1354 struct compat_sigset_argpack __user *from) 1355{ 1356 if (from) { 1357 if (!user_read_access_begin(from, sizeof(*from))) 1358 return -EFAULT; 1359 unsafe_get_user(to->p, &from->p, Efault); 1360 unsafe_get_user(to->size, &from->size, Efault); 1361 user_read_access_end(); 1362 } 1363 return 0; 1364Efault: 1365 user_access_end(); 1366 return -EFAULT; 1367} 1368 1369COMPAT_SYSCALL_DEFINE6(pselect6_time64, int, n, compat_ulong_t __user *, inp, 1370 compat_ulong_t __user *, outp, compat_ulong_t __user *, exp, 1371 struct __kernel_timespec __user *, tsp, void __user *, sig) 1372{ 1373 struct compat_sigset_argpack x = {0, 0}; 1374 1375 if (get_compat_sigset_argpack(&x, sig)) 1376 return -EFAULT; 1377 1378 return do_compat_pselect(n, inp, outp, exp, tsp, compat_ptr(x.p), 1379 x.size, PT_TIMESPEC); 1380} 1381 1382#if defined(CONFIG_COMPAT_32BIT_TIME) 1383 1384COMPAT_SYSCALL_DEFINE6(pselect6_time32, int, n, compat_ulong_t __user *, inp, 1385 compat_ulong_t __user *, outp, compat_ulong_t __user *, exp, 1386 struct old_timespec32 __user *, tsp, void __user *, sig) 1387{ 1388 struct compat_sigset_argpack x = {0, 0}; 1389 1390 if (get_compat_sigset_argpack(&x, sig)) 1391 return -EFAULT; 1392 1393 return do_compat_pselect(n, inp, outp, exp, tsp, compat_ptr(x.p), 1394 x.size, PT_OLD_TIMESPEC); 1395} 1396 1397#endif 1398 1399#if defined(CONFIG_COMPAT_32BIT_TIME) 1400COMPAT_SYSCALL_DEFINE5(ppoll_time32, struct pollfd __user *, ufds, 1401 unsigned int, nfds, struct old_timespec32 __user *, tsp, 1402 const compat_sigset_t __user *, sigmask, compat_size_t, sigsetsize) 1403{ 1404 struct timespec64 ts, end_time, *to = NULL; 1405 int ret; 1406 1407 if (tsp) { 1408 if (get_old_timespec32(&ts, tsp)) 1409 return -EFAULT; 1410 1411 to = &end_time; 1412 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) 1413 return -EINVAL; 1414 } 1415 1416 ret = set_compat_user_sigmask(sigmask, sigsetsize); 1417 if (ret) 1418 return ret; 1419 1420 ret = do_sys_poll(ufds, nfds, to); 1421 return poll_select_finish(&end_time, tsp, PT_OLD_TIMESPEC, ret); 1422} 1423#endif 1424 1425/* New compat syscall for 64 bit time_t*/ 1426COMPAT_SYSCALL_DEFINE5(ppoll_time64, struct pollfd __user *, ufds, 1427 unsigned int, nfds, struct __kernel_timespec __user *, tsp, 1428 const compat_sigset_t __user *, sigmask, compat_size_t, sigsetsize) 1429{ 1430 struct timespec64 ts, end_time, *to = NULL; 1431 int ret; 1432 1433 if (tsp) { 1434 if (get_timespec64(&ts, tsp)) 1435 return -EFAULT; 1436 1437 to = &end_time; 1438 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) 1439 return -EINVAL; 1440 } 1441 1442 ret = set_compat_user_sigmask(sigmask, sigsetsize); 1443 if (ret) 1444 return ret; 1445 1446 ret = do_sys_poll(ufds, nfds, to); 1447 return poll_select_finish(&end_time, tsp, PT_TIMESPEC, ret); 1448} 1449 1450#endif 1451