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/kernel.h>
19#include <linux/sched/signal.h>
20#include <linux/sched/rt.h>
21#include <linux/syscalls.h>
22#include <linux/export.h>
23#include <linux/slab.h>
24#include <linux/poll.h>
25#include <linux/personality.h> /* for STICKY_TIMEOUTS */
26#include <linux/file.h>
27#include <linux/fdtable.h>
28#include <linux/fs.h>
29#include <linux/rcupdate.h>
30#include <linux/hrtimer.h>
31#include <linux/freezer.h>
32#include <net/busy_poll.h>
33#include <linux/vmalloc.h>
34
35#include <linux/uaccess.h>
36
37
38/*
39 * Estimate expected accuracy in ns from a timeval.
40 *
41 * After quite a bit of churning around, we've settled on
42 * a simple thing of taking 0.1% of the timeout as the
43 * slack, with a cap of 100 msec.
44 * "nice" tasks get a 0.5% slack instead.
45 *
46 * Consider this comment an open invitation to come up with even
47 * better solutions..
48 */
49
50#define MAX_SLACK (100 * NSEC_PER_MSEC)
51
52static long __estimate_accuracy(struct timespec64 *tv)
53{
54 long slack;
55 int divfactor = 1000;
56
57 if (tv->tv_sec < 0)
58 return 0;
59
60 if (task_nice(current) > 0)
61 divfactor = divfactor / 5;
62
63 if (tv->tv_sec > MAX_SLACK / (NSEC_PER_SEC/divfactor))
64 return MAX_SLACK;
65
66 slack = tv->tv_nsec / divfactor;
67 slack += tv->tv_sec * (NSEC_PER_SEC/divfactor);
68
69 if (slack > MAX_SLACK)
70 return MAX_SLACK;
71
72 return slack;
73}
74
75u64 select_estimate_accuracy(struct timespec64 *tv)
76{
77 u64 ret;
78 struct timespec64 now;
79
80 /*
81 * Realtime tasks get a slack of 0 for obvious reasons.
82 */
83
84 if (rt_task(current))
85 return 0;
86
87 ktime_get_ts64(&now);
88 now = timespec64_sub(*tv, now);
89 ret = __estimate_accuracy(&now);
90 if (ret < current->timer_slack_ns)
91 return current->timer_slack_ns;
92 return ret;
93}
94
95
96
97struct poll_table_page {
98 struct poll_table_page * next;
99 struct poll_table_entry * entry;
100 struct poll_table_entry entries[0];
101};
102
103#define POLL_TABLE_FULL(table) \
104 ((unsigned long)((table)->entry+1) > PAGE_SIZE + (unsigned long)(table))
105
106/*
107 * Ok, Peter made a complicated, but straightforward multiple_wait() function.
108 * I have rewritten this, taking some shortcuts: This code may not be easy to
109 * follow, but it should be free of race-conditions, and it's practical. If you
110 * understand what I'm doing here, then you understand how the linux
111 * sleep/wakeup mechanism works.
112 *
113 * Two very simple procedures, poll_wait() and poll_freewait() make all the
114 * work. poll_wait() is an inline-function defined in <linux/poll.h>,
115 * as all select/poll functions have to call it to add an entry to the
116 * poll table.
117 */
118static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
119 poll_table *p);
120
121void poll_initwait(struct poll_wqueues *pwq)
122{
123 init_poll_funcptr(&pwq->pt, __pollwait);
124 pwq->polling_task = current;
125 pwq->triggered = 0;
126 pwq->error = 0;
127 pwq->table = NULL;
128 pwq->inline_index = 0;
129}
130EXPORT_SYMBOL(poll_initwait);
131
132static void free_poll_entry(struct poll_table_entry *entry)
133{
134 remove_wait_queue(entry->wait_address, &entry->wait);
135 fput(entry->filp);
136}
137
138void poll_freewait(struct poll_wqueues *pwq)
139{
140 struct poll_table_page * p = pwq->table;
141 int i;
142 for (i = 0; i < pwq->inline_index; i++)
143 free_poll_entry(pwq->inline_entries + i);
144 while (p) {
145 struct poll_table_entry * entry;
146 struct poll_table_page *old;
147
148 entry = p->entry;
149 do {
150 entry--;
151 free_poll_entry(entry);
152 } while (entry > p->entries);
153 old = p;
154 p = p->next;
155 free_page((unsigned long) old);
156 }
157}
158EXPORT_SYMBOL(poll_freewait);
159
160static struct poll_table_entry *poll_get_entry(struct poll_wqueues *p)
161{
162 struct poll_table_page *table = p->table;
163
164 if (p->inline_index < N_INLINE_POLL_ENTRIES)
165 return p->inline_entries + p->inline_index++;
166
167 if (!table || POLL_TABLE_FULL(table)) {
168 struct poll_table_page *new_table;
169
170 new_table = (struct poll_table_page *) __get_free_page(GFP_KERNEL);
171 if (!new_table) {
172 p->error = -ENOMEM;
173 return NULL;
174 }
175 new_table->entry = new_table->entries;
176 new_table->next = table;
177 p->table = new_table;
178 table = new_table;
179 }
180
181 return table->entry++;
182}
183
184static int __pollwake(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
185{
186 struct poll_wqueues *pwq = wait->private;
187 DECLARE_WAITQUEUE(dummy_wait, pwq->polling_task);
188
189 /*
190 * Although this function is called under waitqueue lock, LOCK
191 * doesn't imply write barrier and the users expect write
192 * barrier semantics on wakeup functions. The following
193 * smp_wmb() is equivalent to smp_wmb() in try_to_wake_up()
194 * and is paired with smp_store_mb() in poll_schedule_timeout.
195 */
196 smp_wmb();
197 pwq->triggered = 1;
198
199 /*
200 * Perform the default wake up operation using a dummy
201 * waitqueue.
202 *
203 * TODO: This is hacky but there currently is no interface to
204 * pass in @sync. @sync is scheduled to be removed and once
205 * that happens, wake_up_process() can be used directly.
206 */
207 return default_wake_function(&dummy_wait, mode, sync, key);
208}
209
210static int pollwake(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
211{
212 struct poll_table_entry *entry;
213
214 entry = container_of(wait, struct poll_table_entry, wait);
215 if (key && !(key_to_poll(key) & entry->key))
216 return 0;
217 return __pollwake(wait, mode, sync, key);
218}
219
220/* Add a new entry */
221static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
222 poll_table *p)
223{
224 struct poll_wqueues *pwq = container_of(p, struct poll_wqueues, pt);
225 struct poll_table_entry *entry = poll_get_entry(pwq);
226 if (!entry)
227 return;
228 entry->filp = get_file(filp);
229 entry->wait_address = wait_address;
230 entry->key = p->_key;
231 init_waitqueue_func_entry(&entry->wait, pollwake);
232 entry->wait.private = pwq;
233 add_wait_queue(wait_address, &entry->wait);
234}
235
236static int poll_schedule_timeout(struct poll_wqueues *pwq, int state,
237 ktime_t *expires, unsigned long slack)
238{
239 int rc = -EINTR;
240
241 set_current_state(state);
242 if (!pwq->triggered)
243 rc = schedule_hrtimeout_range(expires, slack, HRTIMER_MODE_ABS);
244 __set_current_state(TASK_RUNNING);
245
246 /*
247 * Prepare for the next iteration.
248 *
249 * The following smp_store_mb() serves two purposes. First, it's
250 * the counterpart rmb of the wmb in pollwake() such that data
251 * written before wake up is always visible after wake up.
252 * Second, the full barrier guarantees that triggered clearing
253 * doesn't pass event check of the next iteration. Note that
254 * this problem doesn't exist for the first iteration as
255 * add_wait_queue() has full barrier semantics.
256 */
257 smp_store_mb(pwq->triggered, 0);
258
259 return rc;
260}
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 */
273int 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
290enum poll_time_type {
291 PT_TIMEVAL = 0,
292 PT_OLD_TIMEVAL = 1,
293 PT_TIMESPEC = 2,
294 PT_OLD_TIMESPEC = 3,
295};
296
297static int poll_select_copy_remaining(struct timespec64 *end_time,
298 void __user *p,
299 enum poll_time_type pt_type, int ret)
300{
301 struct timespec64 rts;
302
303 if (!p)
304 return ret;
305
306 if (current->personality & STICKY_TIMEOUTS)
307 goto sticky;
308
309 /* No update for zero timeout */
310 if (!end_time->tv_sec && !end_time->tv_nsec)
311 return ret;
312
313 ktime_get_ts64(&rts);
314 rts = timespec64_sub(*end_time, rts);
315 if (rts.tv_sec < 0)
316 rts.tv_sec = rts.tv_nsec = 0;
317
318
319 switch (pt_type) {
320 case PT_TIMEVAL:
321 {
322 struct timeval rtv;
323
324 if (sizeof(rtv) > sizeof(rtv.tv_sec) + sizeof(rtv.tv_usec))
325 memset(&rtv, 0, sizeof(rtv));
326 rtv.tv_sec = rts.tv_sec;
327 rtv.tv_usec = rts.tv_nsec / NSEC_PER_USEC;
328 if (!copy_to_user(p, &rtv, sizeof(rtv)))
329 return ret;
330 }
331 break;
332 case PT_OLD_TIMEVAL:
333 {
334 struct old_timeval32 rtv;
335
336 rtv.tv_sec = rts.tv_sec;
337 rtv.tv_usec = rts.tv_nsec / NSEC_PER_USEC;
338 if (!copy_to_user(p, &rtv, sizeof(rtv)))
339 return ret;
340 }
341 break;
342 case PT_TIMESPEC:
343 if (!put_timespec64(&rts, p))
344 return ret;
345 break;
346 case PT_OLD_TIMESPEC:
347 if (!put_old_timespec32(&rts, p))
348 return ret;
349 break;
350 default:
351 BUG();
352 }
353 /*
354 * If an application puts its timeval in read-only memory, we
355 * don't want the Linux-specific update to the timeval to
356 * cause a fault after the select has completed
357 * successfully. However, because we're not updating the
358 * timeval, we can't restart the system call.
359 */
360
361sticky:
362 if (ret == -ERESTARTNOHAND)
363 ret = -EINTR;
364 return ret;
365}
366
367/*
368 * Scalable version of the fd_set.
369 */
370
371typedef struct {
372 unsigned long *in, *out, *ex;
373 unsigned long *res_in, *res_out, *res_ex;
374} fd_set_bits;
375
376/*
377 * How many longwords for "nr" bits?
378 */
379#define FDS_BITPERLONG (8*sizeof(long))
380#define FDS_LONGS(nr) (((nr)+FDS_BITPERLONG-1)/FDS_BITPERLONG)
381#define FDS_BYTES(nr) (FDS_LONGS(nr)*sizeof(long))
382
383/*
384 * Use "unsigned long" accesses to let user-mode fd_set's be long-aligned.
385 */
386static inline
387int get_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
388{
389 nr = FDS_BYTES(nr);
390 if (ufdset)
391 return copy_from_user(fdset, ufdset, nr) ? -EFAULT : 0;
392
393 memset(fdset, 0, nr);
394 return 0;
395}
396
397static inline unsigned long __must_check
398set_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
399{
400 if (ufdset)
401 return __copy_to_user(ufdset, fdset, FDS_BYTES(nr));
402 return 0;
403}
404
405static inline
406void zero_fd_set(unsigned long nr, unsigned long *fdset)
407{
408 memset(fdset, 0, FDS_BYTES(nr));
409}
410
411#define FDS_IN(fds, n) (fds->in + n)
412#define FDS_OUT(fds, n) (fds->out + n)
413#define FDS_EX(fds, n) (fds->ex + n)
414
415#define BITS(fds, n) (*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n))
416
417static int max_select_fd(unsigned long n, fd_set_bits *fds)
418{
419 unsigned long *open_fds;
420 unsigned long set;
421 int max;
422 struct fdtable *fdt;
423
424 /* handle last in-complete long-word first */
425 set = ~(~0UL << (n & (BITS_PER_LONG-1)));
426 n /= BITS_PER_LONG;
427 fdt = files_fdtable(current->files);
428 open_fds = fdt->open_fds + n;
429 max = 0;
430 if (set) {
431 set &= BITS(fds, n);
432 if (set) {
433 if (!(set & ~*open_fds))
434 goto get_max;
435 return -EBADF;
436 }
437 }
438 while (n) {
439 open_fds--;
440 n--;
441 set = BITS(fds, n);
442 if (!set)
443 continue;
444 if (set & ~*open_fds)
445 return -EBADF;
446 if (max)
447 continue;
448get_max:
449 do {
450 max++;
451 set >>= 1;
452 } while (set);
453 max += n * BITS_PER_LONG;
454 }
455
456 return max;
457}
458
459#define POLLIN_SET (EPOLLRDNORM | EPOLLRDBAND | EPOLLIN | EPOLLHUP | EPOLLERR)
460#define POLLOUT_SET (EPOLLWRBAND | EPOLLWRNORM | EPOLLOUT | EPOLLERR)
461#define POLLEX_SET (EPOLLPRI)
462
463static inline void wait_key_set(poll_table *wait, unsigned long in,
464 unsigned long out, unsigned long bit,
465 __poll_t ll_flag)
466{
467 wait->_key = POLLEX_SET | ll_flag;
468 if (in & bit)
469 wait->_key |= POLLIN_SET;
470 if (out & bit)
471 wait->_key |= POLLOUT_SET;
472}
473
474static int do_select(int n, fd_set_bits *fds, struct timespec64 *end_time)
475{
476 ktime_t expire, *to = NULL;
477 struct poll_wqueues table;
478 poll_table *wait;
479 int retval, i, timed_out = 0;
480 u64 slack = 0;
481 __poll_t busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0;
482 unsigned long busy_start = 0;
483
484 rcu_read_lock();
485 retval = max_select_fd(n, fds);
486 rcu_read_unlock();
487
488 if (retval < 0)
489 return retval;
490 n = retval;
491
492 poll_initwait(&table);
493 wait = &table.pt;
494 if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
495 wait->_qproc = NULL;
496 timed_out = 1;
497 }
498
499 if (end_time && !timed_out)
500 slack = select_estimate_accuracy(end_time);
501
502 retval = 0;
503 for (;;) {
504 unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp;
505 bool can_busy_loop = false;
506
507 inp = fds->in; outp = fds->out; exp = fds->ex;
508 rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex;
509
510 for (i = 0; i < n; ++rinp, ++routp, ++rexp) {
511 unsigned long in, out, ex, all_bits, bit = 1, j;
512 unsigned long res_in = 0, res_out = 0, res_ex = 0;
513 __poll_t mask;
514
515 in = *inp++; out = *outp++; ex = *exp++;
516 all_bits = in | out | ex;
517 if (all_bits == 0) {
518 i += BITS_PER_LONG;
519 continue;
520 }
521
522 for (j = 0; j < BITS_PER_LONG; ++j, ++i, bit <<= 1) {
523 struct fd f;
524 if (i >= n)
525 break;
526 if (!(bit & all_bits))
527 continue;
528 f = fdget(i);
529 if (f.file) {
530 wait_key_set(wait, in, out, bit,
531 busy_flag);
532 mask = vfs_poll(f.file, wait);
533
534 fdput(f);
535 if ((mask & POLLIN_SET) && (in & bit)) {
536 res_in |= bit;
537 retval++;
538 wait->_qproc = NULL;
539 }
540 if ((mask & POLLOUT_SET) && (out & bit)) {
541 res_out |= bit;
542 retval++;
543 wait->_qproc = NULL;
544 }
545 if ((mask & POLLEX_SET) && (ex & bit)) {
546 res_ex |= bit;
547 retval++;
548 wait->_qproc = NULL;
549 }
550 /* got something, stop busy polling */
551 if (retval) {
552 can_busy_loop = false;
553 busy_flag = 0;
554
555 /*
556 * only remember a returned
557 * POLL_BUSY_LOOP if we asked for it
558 */
559 } else if (busy_flag & mask)
560 can_busy_loop = true;
561
562 }
563 }
564 if (res_in)
565 *rinp = res_in;
566 if (res_out)
567 *routp = res_out;
568 if (res_ex)
569 *rexp = res_ex;
570 cond_resched();
571 }
572 wait->_qproc = NULL;
573 if (retval || timed_out || signal_pending(current))
574 break;
575 if (table.error) {
576 retval = table.error;
577 break;
578 }
579
580 /* only if found POLL_BUSY_LOOP sockets && not out of time */
581 if (can_busy_loop && !need_resched()) {
582 if (!busy_start) {
583 busy_start = busy_loop_current_time();
584 continue;
585 }
586 if (!busy_loop_timeout(busy_start))
587 continue;
588 }
589 busy_flag = 0;
590
591 /*
592 * If this is the first loop and we have a timeout
593 * given, then we convert to ktime_t and set the to
594 * pointer to the expiry value.
595 */
596 if (end_time && !to) {
597 expire = timespec64_to_ktime(*end_time);
598 to = &expire;
599 }
600
601 if (!poll_schedule_timeout(&table, TASK_INTERRUPTIBLE,
602 to, slack))
603 timed_out = 1;
604 }
605
606 poll_freewait(&table);
607
608 return retval;
609}
610
611/*
612 * We can actually return ERESTARTSYS instead of EINTR, but I'd
613 * like to be certain this leads to no problems. So I return
614 * EINTR just for safety.
615 *
616 * Update: ERESTARTSYS breaks at least the xview clock binary, so
617 * I'm trying ERESTARTNOHAND which restart only when you want to.
618 */
619int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
620 fd_set __user *exp, struct timespec64 *end_time)
621{
622 fd_set_bits fds;
623 void *bits;
624 int ret, max_fds;
625 size_t size, alloc_size;
626 struct fdtable *fdt;
627 /* Allocate small arguments on the stack to save memory and be faster */
628 long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
629
630 ret = -EINVAL;
631 if (n < 0)
632 goto out_nofds;
633
634 /* max_fds can increase, so grab it once to avoid race */
635 rcu_read_lock();
636 fdt = files_fdtable(current->files);
637 max_fds = fdt->max_fds;
638 rcu_read_unlock();
639 if (n > max_fds)
640 n = max_fds;
641
642 /*
643 * We need 6 bitmaps (in/out/ex for both incoming and outgoing),
644 * since we used fdset we need to allocate memory in units of
645 * long-words.
646 */
647 size = FDS_BYTES(n);
648 bits = stack_fds;
649 if (size > sizeof(stack_fds) / 6) {
650 /* Not enough space in on-stack array; must use kmalloc */
651 ret = -ENOMEM;
652 if (size > (SIZE_MAX / 6))
653 goto out_nofds;
654
655 alloc_size = 6 * size;
656 bits = kvmalloc(alloc_size, GFP_KERNEL);
657 if (!bits)
658 goto out_nofds;
659 }
660 fds.in = bits;
661 fds.out = bits + size;
662 fds.ex = bits + 2*size;
663 fds.res_in = bits + 3*size;
664 fds.res_out = bits + 4*size;
665 fds.res_ex = bits + 5*size;
666
667 if ((ret = get_fd_set(n, inp, fds.in)) ||
668 (ret = get_fd_set(n, outp, fds.out)) ||
669 (ret = get_fd_set(n, exp, fds.ex)))
670 goto out;
671 zero_fd_set(n, fds.res_in);
672 zero_fd_set(n, fds.res_out);
673 zero_fd_set(n, fds.res_ex);
674
675 ret = do_select(n, &fds, end_time);
676
677 if (ret < 0)
678 goto out;
679 if (!ret) {
680 ret = -ERESTARTNOHAND;
681 if (signal_pending(current))
682 goto out;
683 ret = 0;
684 }
685
686 if (set_fd_set(n, inp, fds.res_in) ||
687 set_fd_set(n, outp, fds.res_out) ||
688 set_fd_set(n, exp, fds.res_ex))
689 ret = -EFAULT;
690
691out:
692 if (bits != stack_fds)
693 kvfree(bits);
694out_nofds:
695 return ret;
696}
697
698static int kern_select(int n, fd_set __user *inp, fd_set __user *outp,
699 fd_set __user *exp, struct timeval __user *tvp)
700{
701 struct timespec64 end_time, *to = NULL;
702 struct timeval tv;
703 int ret;
704
705 if (tvp) {
706 if (copy_from_user(&tv, tvp, sizeof(tv)))
707 return -EFAULT;
708
709 to = &end_time;
710 if (poll_select_set_timeout(to,
711 tv.tv_sec + (tv.tv_usec / USEC_PER_SEC),
712 (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC))
713 return -EINVAL;
714 }
715
716 ret = core_sys_select(n, inp, outp, exp, to);
717 ret = poll_select_copy_remaining(&end_time, tvp, PT_TIMEVAL, ret);
718
719 return ret;
720}
721
722SYSCALL_DEFINE5(select, int, n, fd_set __user *, inp, fd_set __user *, outp,
723 fd_set __user *, exp, struct timeval __user *, tvp)
724{
725 return kern_select(n, inp, outp, exp, tvp);
726}
727
728static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp,
729 fd_set __user *exp, void __user *tsp,
730 const sigset_t __user *sigmask, size_t sigsetsize,
731 enum poll_time_type type)
732{
733 sigset_t ksigmask, sigsaved;
734 struct timespec64 ts, end_time, *to = NULL;
735 int ret;
736
737 if (tsp) {
738 switch (type) {
739 case PT_TIMESPEC:
740 if (get_timespec64(&ts, tsp))
741 return -EFAULT;
742 break;
743 case PT_OLD_TIMESPEC:
744 if (get_old_timespec32(&ts, tsp))
745 return -EFAULT;
746 break;
747 default:
748 BUG();
749 }
750
751 to = &end_time;
752 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
753 return -EINVAL;
754 }
755
756 ret = set_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize);
757 if (ret)
758 return ret;
759
760 ret = core_sys_select(n, inp, outp, exp, to);
761 ret = poll_select_copy_remaining(&end_time, tsp, type, ret);
762
763 restore_user_sigmask(sigmask, &sigsaved);
764
765 return ret;
766}
767
768/*
769 * Most architectures can't handle 7-argument syscalls. So we provide a
770 * 6-argument version where the sixth argument is a pointer to a structure
771 * which has a pointer to the sigset_t itself followed by a size_t containing
772 * the sigset size.
773 */
774SYSCALL_DEFINE6(pselect6, int, n, fd_set __user *, inp, fd_set __user *, outp,
775 fd_set __user *, exp, struct __kernel_timespec __user *, tsp,
776 void __user *, sig)
777{
778 size_t sigsetsize = 0;
779 sigset_t __user *up = NULL;
780
781 if (sig) {
782 if (!access_ok(sig, sizeof(void *)+sizeof(size_t))
783 || __get_user(up, (sigset_t __user * __user *)sig)
784 || __get_user(sigsetsize,
785 (size_t __user *)(sig+sizeof(void *))))
786 return -EFAULT;
787 }
788
789 return do_pselect(n, inp, outp, exp, tsp, up, sigsetsize, PT_TIMESPEC);
790}
791
792#if defined(CONFIG_COMPAT_32BIT_TIME) && !defined(CONFIG_64BIT)
793
794SYSCALL_DEFINE6(pselect6_time32, int, n, fd_set __user *, inp, fd_set __user *, outp,
795 fd_set __user *, exp, struct old_timespec32 __user *, tsp,
796 void __user *, sig)
797{
798 size_t sigsetsize = 0;
799 sigset_t __user *up = NULL;
800
801 if (sig) {
802 if (!access_ok(sig, sizeof(void *)+sizeof(size_t))
803 || __get_user(up, (sigset_t __user * __user *)sig)
804 || __get_user(sigsetsize,
805 (size_t __user *)(sig+sizeof(void *))))
806 return -EFAULT;
807 }
808
809 return do_pselect(n, inp, outp, exp, tsp, up, sigsetsize, PT_OLD_TIMESPEC);
810}
811
812#endif
813
814#ifdef __ARCH_WANT_SYS_OLD_SELECT
815struct sel_arg_struct {
816 unsigned long n;
817 fd_set __user *inp, *outp, *exp;
818 struct timeval __user *tvp;
819};
820
821SYSCALL_DEFINE1(old_select, struct sel_arg_struct __user *, arg)
822{
823 struct sel_arg_struct a;
824
825 if (copy_from_user(&a, arg, sizeof(a)))
826 return -EFAULT;
827 return kern_select(a.n, a.inp, a.outp, a.exp, a.tvp);
828}
829#endif
830
831struct poll_list {
832 struct poll_list *next;
833 int len;
834 struct pollfd entries[0];
835};
836
837#define POLLFD_PER_PAGE ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd))
838
839/*
840 * Fish for pollable events on the pollfd->fd file descriptor. We're only
841 * interested in events matching the pollfd->events mask, and the result
842 * matching that mask is both recorded in pollfd->revents and returned. The
843 * pwait poll_table will be used by the fd-provided poll handler for waiting,
844 * if pwait->_qproc is non-NULL.
845 */
846static inline __poll_t do_pollfd(struct pollfd *pollfd, poll_table *pwait,
847 bool *can_busy_poll,
848 __poll_t busy_flag)
849{
850 int fd = pollfd->fd;
851 __poll_t mask = 0, filter;
852 struct fd f;
853
854 if (fd < 0)
855 goto out;
856 mask = EPOLLNVAL;
857 f = fdget(fd);
858 if (!f.file)
859 goto out;
860
861 /* userland u16 ->events contains POLL... bitmap */
862 filter = demangle_poll(pollfd->events) | EPOLLERR | EPOLLHUP;
863 pwait->_key = filter | busy_flag;
864 mask = vfs_poll(f.file, pwait);
865 if (mask & busy_flag)
866 *can_busy_poll = true;
867 mask &= filter; /* Mask out unneeded events. */
868 fdput(f);
869
870out:
871 /* ... and so does ->revents */
872 pollfd->revents = mangle_poll(mask);
873 return mask;
874}
875
876static int do_poll(struct poll_list *list, struct poll_wqueues *wait,
877 struct timespec64 *end_time)
878{
879 poll_table* pt = &wait->pt;
880 ktime_t expire, *to = NULL;
881 int timed_out = 0, count = 0;
882 u64 slack = 0;
883 __poll_t busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0;
884 unsigned long busy_start = 0;
885
886 /* Optimise the no-wait case */
887 if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
888 pt->_qproc = NULL;
889 timed_out = 1;
890 }
891
892 if (end_time && !timed_out)
893 slack = select_estimate_accuracy(end_time);
894
895 for (;;) {
896 struct poll_list *walk;
897 bool can_busy_loop = false;
898
899 for (walk = list; walk != NULL; walk = walk->next) {
900 struct pollfd * pfd, * pfd_end;
901
902 pfd = walk->entries;
903 pfd_end = pfd + walk->len;
904 for (; pfd != pfd_end; pfd++) {
905 /*
906 * Fish for events. If we found one, record it
907 * and kill poll_table->_qproc, so we don't
908 * needlessly register any other waiters after
909 * this. They'll get immediately deregistered
910 * when we break out and return.
911 */
912 if (do_pollfd(pfd, pt, &can_busy_loop,
913 busy_flag)) {
914 count++;
915 pt->_qproc = NULL;
916 /* found something, stop busy polling */
917 busy_flag = 0;
918 can_busy_loop = false;
919 }
920 }
921 }
922 /*
923 * All waiters have already been registered, so don't provide
924 * a poll_table->_qproc to them on the next loop iteration.
925 */
926 pt->_qproc = NULL;
927 if (!count) {
928 count = wait->error;
929 if (signal_pending(current))
930 count = -EINTR;
931 }
932 if (count || timed_out)
933 break;
934
935 /* only if found POLL_BUSY_LOOP sockets && not out of time */
936 if (can_busy_loop && !need_resched()) {
937 if (!busy_start) {
938 busy_start = busy_loop_current_time();
939 continue;
940 }
941 if (!busy_loop_timeout(busy_start))
942 continue;
943 }
944 busy_flag = 0;
945
946 /*
947 * If this is the first loop and we have a timeout
948 * given, then we convert to ktime_t and set the to
949 * pointer to the expiry value.
950 */
951 if (end_time && !to) {
952 expire = timespec64_to_ktime(*end_time);
953 to = &expire;
954 }
955
956 if (!poll_schedule_timeout(wait, TASK_INTERRUPTIBLE, to, slack))
957 timed_out = 1;
958 }
959 return count;
960}
961
962#define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \
963 sizeof(struct pollfd))
964
965static int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,
966 struct timespec64 *end_time)
967{
968 struct poll_wqueues table;
969 int err = -EFAULT, fdcount, len, size;
970 /* Allocate small arguments on the stack to save memory and be
971 faster - use long to make sure the buffer is aligned properly
972 on 64 bit archs to avoid unaligned access */
973 long stack_pps[POLL_STACK_ALLOC/sizeof(long)];
974 struct poll_list *const head = (struct poll_list *)stack_pps;
975 struct poll_list *walk = head;
976 unsigned long todo = nfds;
977
978 if (nfds > rlimit(RLIMIT_NOFILE))
979 return -EINVAL;
980
981 len = min_t(unsigned int, nfds, N_STACK_PPS);
982 for (;;) {
983 walk->next = NULL;
984 walk->len = len;
985 if (!len)
986 break;
987
988 if (copy_from_user(walk->entries, ufds + nfds-todo,
989 sizeof(struct pollfd) * walk->len))
990 goto out_fds;
991
992 todo -= walk->len;
993 if (!todo)
994 break;
995
996 len = min(todo, POLLFD_PER_PAGE);
997 size = sizeof(struct poll_list) + sizeof(struct pollfd) * len;
998 walk = walk->next = kmalloc(size, GFP_KERNEL);
999 if (!walk) {
1000 err = -ENOMEM;
1001 goto out_fds;
1002 }
1003 }
1004
1005 poll_initwait(&table);
1006 fdcount = do_poll(head, &table, end_time);
1007 poll_freewait(&table);
1008
1009 for (walk = head; walk; walk = walk->next) {
1010 struct pollfd *fds = walk->entries;
1011 int j;
1012
1013 for (j = 0; j < walk->len; j++, ufds++)
1014 if (__put_user(fds[j].revents, &ufds->revents))
1015 goto out_fds;
1016 }
1017
1018 err = fdcount;
1019out_fds:
1020 walk = head->next;
1021 while (walk) {
1022 struct poll_list *pos = walk;
1023 walk = walk->next;
1024 kfree(pos);
1025 }
1026
1027 return err;
1028}
1029
1030static long do_restart_poll(struct restart_block *restart_block)
1031{
1032 struct pollfd __user *ufds = restart_block->poll.ufds;
1033 int nfds = restart_block->poll.nfds;
1034 struct timespec64 *to = NULL, end_time;
1035 int ret;
1036
1037 if (restart_block->poll.has_timeout) {
1038 end_time.tv_sec = restart_block->poll.tv_sec;
1039 end_time.tv_nsec = restart_block->poll.tv_nsec;
1040 to = &end_time;
1041 }
1042
1043 ret = do_sys_poll(ufds, nfds, to);
1044
1045 if (ret == -EINTR) {
1046 restart_block->fn = do_restart_poll;
1047 ret = -ERESTART_RESTARTBLOCK;
1048 }
1049 return ret;
1050}
1051
1052SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds,
1053 int, timeout_msecs)
1054{
1055 struct timespec64 end_time, *to = NULL;
1056 int ret;
1057
1058 if (timeout_msecs >= 0) {
1059 to = &end_time;
1060 poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC,
1061 NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC));
1062 }
1063
1064 ret = do_sys_poll(ufds, nfds, to);
1065
1066 if (ret == -EINTR) {
1067 struct restart_block *restart_block;
1068
1069 restart_block = &current->restart_block;
1070 restart_block->fn = do_restart_poll;
1071 restart_block->poll.ufds = ufds;
1072 restart_block->poll.nfds = nfds;
1073
1074 if (timeout_msecs >= 0) {
1075 restart_block->poll.tv_sec = end_time.tv_sec;
1076 restart_block->poll.tv_nsec = end_time.tv_nsec;
1077 restart_block->poll.has_timeout = 1;
1078 } else
1079 restart_block->poll.has_timeout = 0;
1080
1081 ret = -ERESTART_RESTARTBLOCK;
1082 }
1083 return ret;
1084}
1085
1086SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds,
1087 struct __kernel_timespec __user *, tsp, const sigset_t __user *, sigmask,
1088 size_t, sigsetsize)
1089{
1090 sigset_t ksigmask, sigsaved;
1091 struct timespec64 ts, end_time, *to = NULL;
1092 int ret;
1093
1094 if (tsp) {
1095 if (get_timespec64(&ts, tsp))
1096 return -EFAULT;
1097
1098 to = &end_time;
1099 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
1100 return -EINVAL;
1101 }
1102
1103 ret = set_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize);
1104 if (ret)
1105 return ret;
1106
1107 ret = do_sys_poll(ufds, nfds, to);
1108
1109 restore_user_sigmask(sigmask, &sigsaved);
1110
1111 /* We can restart this syscall, usually */
1112 if (ret == -EINTR)
1113 ret = -ERESTARTNOHAND;
1114
1115 ret = poll_select_copy_remaining(&end_time, tsp, PT_TIMESPEC, ret);
1116
1117 return ret;
1118}
1119
1120#if defined(CONFIG_COMPAT_32BIT_TIME) && !defined(CONFIG_64BIT)
1121
1122SYSCALL_DEFINE5(ppoll_time32, struct pollfd __user *, ufds, unsigned int, nfds,
1123 struct old_timespec32 __user *, tsp, const sigset_t __user *, sigmask,
1124 size_t, sigsetsize)
1125{
1126 sigset_t ksigmask, sigsaved;
1127 struct timespec64 ts, end_time, *to = NULL;
1128 int ret;
1129
1130 if (tsp) {
1131 if (get_old_timespec32(&ts, tsp))
1132 return -EFAULT;
1133
1134 to = &end_time;
1135 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
1136 return -EINVAL;
1137 }
1138
1139 ret = set_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize);
1140 if (ret)
1141 return ret;
1142
1143 ret = do_sys_poll(ufds, nfds, to);
1144
1145 restore_user_sigmask(sigmask, &sigsaved);
1146
1147 /* We can restart this syscall, usually */
1148 if (ret == -EINTR)
1149 ret = -ERESTARTNOHAND;
1150
1151 ret = poll_select_copy_remaining(&end_time, tsp, PT_OLD_TIMESPEC, ret);
1152
1153 return ret;
1154}
1155#endif
1156
1157#ifdef CONFIG_COMPAT
1158#define __COMPAT_NFDBITS (8 * sizeof(compat_ulong_t))
1159
1160/*
1161 * Ooo, nasty. We need here to frob 32-bit unsigned longs to
1162 * 64-bit unsigned longs.
1163 */
1164static
1165int compat_get_fd_set(unsigned long nr, compat_ulong_t __user *ufdset,
1166 unsigned long *fdset)
1167{
1168 if (ufdset) {
1169 return compat_get_bitmap(fdset, ufdset, nr);
1170 } else {
1171 zero_fd_set(nr, fdset);
1172 return 0;
1173 }
1174}
1175
1176static
1177int compat_set_fd_set(unsigned long nr, compat_ulong_t __user *ufdset,
1178 unsigned long *fdset)
1179{
1180 if (!ufdset)
1181 return 0;
1182 return compat_put_bitmap(ufdset, fdset, nr);
1183}
1184
1185
1186/*
1187 * This is a virtual copy of sys_select from fs/select.c and probably
1188 * should be compared to it from time to time
1189 */
1190
1191/*
1192 * We can actually return ERESTARTSYS instead of EINTR, but I'd
1193 * like to be certain this leads to no problems. So I return
1194 * EINTR just for safety.
1195 *
1196 * Update: ERESTARTSYS breaks at least the xview clock binary, so
1197 * I'm trying ERESTARTNOHAND which restart only when you want to.
1198 */
1199static int compat_core_sys_select(int n, compat_ulong_t __user *inp,
1200 compat_ulong_t __user *outp, compat_ulong_t __user *exp,
1201 struct timespec64 *end_time)
1202{
1203 fd_set_bits fds;
1204 void *bits;
1205 int size, max_fds, ret = -EINVAL;
1206 struct fdtable *fdt;
1207 long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
1208
1209 if (n < 0)
1210 goto out_nofds;
1211
1212 /* max_fds can increase, so grab it once to avoid race */
1213 rcu_read_lock();
1214 fdt = files_fdtable(current->files);
1215 max_fds = fdt->max_fds;
1216 rcu_read_unlock();
1217 if (n > max_fds)
1218 n = max_fds;
1219
1220 /*
1221 * We need 6 bitmaps (in/out/ex for both incoming and outgoing),
1222 * since we used fdset we need to allocate memory in units of
1223 * long-words.
1224 */
1225 size = FDS_BYTES(n);
1226 bits = stack_fds;
1227 if (size > sizeof(stack_fds) / 6) {
1228 bits = kmalloc_array(6, size, GFP_KERNEL);
1229 ret = -ENOMEM;
1230 if (!bits)
1231 goto out_nofds;
1232 }
1233 fds.in = (unsigned long *) bits;
1234 fds.out = (unsigned long *) (bits + size);
1235 fds.ex = (unsigned long *) (bits + 2*size);
1236 fds.res_in = (unsigned long *) (bits + 3*size);
1237 fds.res_out = (unsigned long *) (bits + 4*size);
1238 fds.res_ex = (unsigned long *) (bits + 5*size);
1239
1240 if ((ret = compat_get_fd_set(n, inp, fds.in)) ||
1241 (ret = compat_get_fd_set(n, outp, fds.out)) ||
1242 (ret = compat_get_fd_set(n, exp, fds.ex)))
1243 goto out;
1244 zero_fd_set(n, fds.res_in);
1245 zero_fd_set(n, fds.res_out);
1246 zero_fd_set(n, fds.res_ex);
1247
1248 ret = do_select(n, &fds, end_time);
1249
1250 if (ret < 0)
1251 goto out;
1252 if (!ret) {
1253 ret = -ERESTARTNOHAND;
1254 if (signal_pending(current))
1255 goto out;
1256 ret = 0;
1257 }
1258
1259 if (compat_set_fd_set(n, inp, fds.res_in) ||
1260 compat_set_fd_set(n, outp, fds.res_out) ||
1261 compat_set_fd_set(n, exp, fds.res_ex))
1262 ret = -EFAULT;
1263out:
1264 if (bits != stack_fds)
1265 kfree(bits);
1266out_nofds:
1267 return ret;
1268}
1269
1270static int do_compat_select(int n, compat_ulong_t __user *inp,
1271 compat_ulong_t __user *outp, compat_ulong_t __user *exp,
1272 struct old_timeval32 __user *tvp)
1273{
1274 struct timespec64 end_time, *to = NULL;
1275 struct old_timeval32 tv;
1276 int ret;
1277
1278 if (tvp) {
1279 if (copy_from_user(&tv, tvp, sizeof(tv)))
1280 return -EFAULT;
1281
1282 to = &end_time;
1283 if (poll_select_set_timeout(to,
1284 tv.tv_sec + (tv.tv_usec / USEC_PER_SEC),
1285 (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC))
1286 return -EINVAL;
1287 }
1288
1289 ret = compat_core_sys_select(n, inp, outp, exp, to);
1290 ret = poll_select_copy_remaining(&end_time, tvp, PT_OLD_TIMEVAL, ret);
1291
1292 return ret;
1293}
1294
1295COMPAT_SYSCALL_DEFINE5(select, int, n, compat_ulong_t __user *, inp,
1296 compat_ulong_t __user *, outp, compat_ulong_t __user *, exp,
1297 struct old_timeval32 __user *, tvp)
1298{
1299 return do_compat_select(n, inp, outp, exp, tvp);
1300}
1301
1302struct compat_sel_arg_struct {
1303 compat_ulong_t n;
1304 compat_uptr_t inp;
1305 compat_uptr_t outp;
1306 compat_uptr_t exp;
1307 compat_uptr_t tvp;
1308};
1309
1310COMPAT_SYSCALL_DEFINE1(old_select, struct compat_sel_arg_struct __user *, arg)
1311{
1312 struct compat_sel_arg_struct a;
1313
1314 if (copy_from_user(&a, arg, sizeof(a)))
1315 return -EFAULT;
1316 return do_compat_select(a.n, compat_ptr(a.inp), compat_ptr(a.outp),
1317 compat_ptr(a.exp), compat_ptr(a.tvp));
1318}
1319
1320static long do_compat_pselect(int n, compat_ulong_t __user *inp,
1321 compat_ulong_t __user *outp, compat_ulong_t __user *exp,
1322 void __user *tsp, compat_sigset_t __user *sigmask,
1323 compat_size_t sigsetsize, enum poll_time_type type)
1324{
1325 sigset_t ksigmask, sigsaved;
1326 struct timespec64 ts, end_time, *to = NULL;
1327 int ret;
1328
1329 if (tsp) {
1330 switch (type) {
1331 case PT_OLD_TIMESPEC:
1332 if (get_old_timespec32(&ts, tsp))
1333 return -EFAULT;
1334 break;
1335 case PT_TIMESPEC:
1336 if (get_timespec64(&ts, tsp))
1337 return -EFAULT;
1338 break;
1339 default:
1340 BUG();
1341 }
1342
1343 to = &end_time;
1344 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
1345 return -EINVAL;
1346 }
1347
1348 ret = set_compat_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize);
1349 if (ret)
1350 return ret;
1351
1352 ret = compat_core_sys_select(n, inp, outp, exp, to);
1353 ret = poll_select_copy_remaining(&end_time, tsp, type, ret);
1354
1355 restore_user_sigmask(sigmask, &sigsaved);
1356
1357 return ret;
1358}
1359
1360COMPAT_SYSCALL_DEFINE6(pselect6_time64, int, n, compat_ulong_t __user *, inp,
1361 compat_ulong_t __user *, outp, compat_ulong_t __user *, exp,
1362 struct __kernel_timespec __user *, tsp, void __user *, sig)
1363{
1364 compat_size_t sigsetsize = 0;
1365 compat_uptr_t up = 0;
1366
1367 if (sig) {
1368 if (!access_ok(sig,
1369 sizeof(compat_uptr_t)+sizeof(compat_size_t)) ||
1370 __get_user(up, (compat_uptr_t __user *)sig) ||
1371 __get_user(sigsetsize,
1372 (compat_size_t __user *)(sig+sizeof(up))))
1373 return -EFAULT;
1374 }
1375
1376 return do_compat_pselect(n, inp, outp, exp, tsp, compat_ptr(up),
1377 sigsetsize, PT_TIMESPEC);
1378}
1379
1380#if defined(CONFIG_COMPAT_32BIT_TIME)
1381
1382COMPAT_SYSCALL_DEFINE6(pselect6_time32, int, n, compat_ulong_t __user *, inp,
1383 compat_ulong_t __user *, outp, compat_ulong_t __user *, exp,
1384 struct old_timespec32 __user *, tsp, void __user *, sig)
1385{
1386 compat_size_t sigsetsize = 0;
1387 compat_uptr_t up = 0;
1388
1389 if (sig) {
1390 if (!access_ok(sig,
1391 sizeof(compat_uptr_t)+sizeof(compat_size_t)) ||
1392 __get_user(up, (compat_uptr_t __user *)sig) ||
1393 __get_user(sigsetsize,
1394 (compat_size_t __user *)(sig+sizeof(up))))
1395 return -EFAULT;
1396 }
1397
1398 return do_compat_pselect(n, inp, outp, exp, tsp, compat_ptr(up),
1399 sigsetsize, PT_OLD_TIMESPEC);
1400}
1401
1402#endif
1403
1404#if defined(CONFIG_COMPAT_32BIT_TIME)
1405COMPAT_SYSCALL_DEFINE5(ppoll_time32, struct pollfd __user *, ufds,
1406 unsigned int, nfds, struct old_timespec32 __user *, tsp,
1407 const compat_sigset_t __user *, sigmask, compat_size_t, sigsetsize)
1408{
1409 sigset_t ksigmask, sigsaved;
1410 struct timespec64 ts, end_time, *to = NULL;
1411 int ret;
1412
1413 if (tsp) {
1414 if (get_old_timespec32(&ts, tsp))
1415 return -EFAULT;
1416
1417 to = &end_time;
1418 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
1419 return -EINVAL;
1420 }
1421
1422 ret = set_compat_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize);
1423 if (ret)
1424 return ret;
1425
1426 ret = do_sys_poll(ufds, nfds, to);
1427
1428 restore_user_sigmask(sigmask, &sigsaved);
1429
1430 /* We can restart this syscall, usually */
1431 if (ret == -EINTR)
1432 ret = -ERESTARTNOHAND;
1433
1434 ret = poll_select_copy_remaining(&end_time, tsp, PT_OLD_TIMESPEC, ret);
1435
1436 return ret;
1437}
1438#endif
1439
1440/* New compat syscall for 64 bit time_t*/
1441COMPAT_SYSCALL_DEFINE5(ppoll_time64, struct pollfd __user *, ufds,
1442 unsigned int, nfds, struct __kernel_timespec __user *, tsp,
1443 const compat_sigset_t __user *, sigmask, compat_size_t, sigsetsize)
1444{
1445 sigset_t ksigmask, sigsaved;
1446 struct timespec64 ts, end_time, *to = NULL;
1447 int ret;
1448
1449 if (tsp) {
1450 if (get_timespec64(&ts, tsp))
1451 return -EFAULT;
1452
1453 to = &end_time;
1454 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
1455 return -EINVAL;
1456 }
1457
1458 ret = set_compat_user_sigmask(sigmask, &ksigmask, &sigsaved, sigsetsize);
1459 if (ret)
1460 return ret;
1461
1462 ret = do_sys_poll(ufds, nfds, to);
1463
1464 restore_user_sigmask(sigmask, &sigsaved);
1465
1466 /* We can restart this syscall, usually */
1467 if (ret == -EINTR)
1468 ret = -ERESTARTNOHAND;
1469
1470 ret = poll_select_copy_remaining(&end_time, tsp, PT_TIMESPEC, ret);
1471
1472 return ret;
1473}
1474
1475#endif
1476