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17#include <linux/kernel.h>
18#include <linux/sched.h>
19#include <linux/syscalls.h>
20#include <linux/export.h>
21#include <linux/slab.h>
22#include <linux/poll.h>
23#include <linux/personality.h>
24#include <linux/file.h>
25#include <linux/fdtable.h>
26#include <linux/fs.h>
27#include <linux/rcupdate.h>
28#include <linux/hrtimer.h>
29#include <linux/sched/rt.h>
30#include <linux/freezer.h>
31#include <net/busy_poll.h>
32#include <linux/vmalloc.h>
33
34#include <asm/uaccess.h>
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49#define MAX_SLACK (100 * NSEC_PER_MSEC)
50
51static 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
74u64 select_estimate_accuracy(struct timespec64 *tv)
75{
76 u64 ret;
77 struct timespec64 now;
78
79
80
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
96struct 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
107
108
109
110
111
112
113
114
115
116
117static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
118 poll_table *p);
119
120void 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}
129EXPORT_SYMBOL(poll_initwait);
130
131static 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
137void 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}
157EXPORT_SYMBOL(poll_freewait);
158
159static 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
183static 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
190
191
192
193
194
195 smp_wmb();
196 pwq->triggered = 1;
197
198
199
200
201
202
203
204
205
206 return default_wake_function(&dummy_wait, mode, sync, key);
207}
208
209static 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
220static 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
235int 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
247
248
249
250
251
252
253
254
255
256 smp_store_mb(pwq->triggered, 0);
257
258 return rc;
259}
260EXPORT_SYMBOL(poll_schedule_timeout);
261
262
263
264
265
266
267
268
269
270
271
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
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
290static 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
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
329
330
331
332
333
334
335sticky:
336 if (ret == -ERESTARTNOHAND)
337 ret = -EINTR;
338 return ret;
339}
340
341#define FDS_IN(fds, n) (fds->in + n)
342#define FDS_OUT(fds, n) (fds->out + n)
343#define FDS_EX(fds, n) (fds->ex + n)
344
345#define BITS(fds, n) (*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n))
346
347static int max_select_fd(unsigned long n, fd_set_bits *fds)
348{
349 unsigned long *open_fds;
350 unsigned long set;
351 int max;
352 struct fdtable *fdt;
353
354
355 set = ~(~0UL << (n & (BITS_PER_LONG-1)));
356 n /= BITS_PER_LONG;
357 fdt = files_fdtable(current->files);
358 open_fds = fdt->open_fds + n;
359 max = 0;
360 if (set) {
361 set &= BITS(fds, n);
362 if (set) {
363 if (!(set & ~*open_fds))
364 goto get_max;
365 return -EBADF;
366 }
367 }
368 while (n) {
369 open_fds--;
370 n--;
371 set = BITS(fds, n);
372 if (!set)
373 continue;
374 if (set & ~*open_fds)
375 return -EBADF;
376 if (max)
377 continue;
378get_max:
379 do {
380 max++;
381 set >>= 1;
382 } while (set);
383 max += n * BITS_PER_LONG;
384 }
385
386 return max;
387}
388
389#define POLLIN_SET (POLLRDNORM | POLLRDBAND | POLLIN | POLLHUP | POLLERR)
390#define POLLOUT_SET (POLLWRBAND | POLLWRNORM | POLLOUT | POLLERR)
391#define POLLEX_SET (POLLPRI)
392
393static inline void wait_key_set(poll_table *wait, unsigned long in,
394 unsigned long out, unsigned long bit,
395 unsigned int ll_flag)
396{
397 wait->_key = POLLEX_SET | ll_flag;
398 if (in & bit)
399 wait->_key |= POLLIN_SET;
400 if (out & bit)
401 wait->_key |= POLLOUT_SET;
402}
403
404int do_select(int n, fd_set_bits *fds, struct timespec64 *end_time)
405{
406 ktime_t expire, *to = NULL;
407 struct poll_wqueues table;
408 poll_table *wait;
409 int retval, i, timed_out = 0;
410 u64 slack = 0;
411 unsigned int busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0;
412 unsigned long busy_end = 0;
413
414 rcu_read_lock();
415 retval = max_select_fd(n, fds);
416 rcu_read_unlock();
417
418 if (retval < 0)
419 return retval;
420 n = retval;
421
422 poll_initwait(&table);
423 wait = &table.pt;
424 if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
425 wait->_qproc = NULL;
426 timed_out = 1;
427 }
428
429 if (end_time && !timed_out)
430 slack = select_estimate_accuracy(end_time);
431
432 retval = 0;
433 for (;;) {
434 unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp;
435 bool can_busy_loop = false;
436
437 inp = fds->in; outp = fds->out; exp = fds->ex;
438 rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex;
439
440 for (i = 0; i < n; ++rinp, ++routp, ++rexp) {
441 unsigned long in, out, ex, all_bits, bit = 1, mask, j;
442 unsigned long res_in = 0, res_out = 0, res_ex = 0;
443
444 in = *inp++; out = *outp++; ex = *exp++;
445 all_bits = in | out | ex;
446 if (all_bits == 0) {
447 i += BITS_PER_LONG;
448 continue;
449 }
450
451 for (j = 0; j < BITS_PER_LONG; ++j, ++i, bit <<= 1) {
452 struct fd f;
453 if (i >= n)
454 break;
455 if (!(bit & all_bits))
456 continue;
457 f = fdget(i);
458 if (f.file) {
459 const struct file_operations *f_op;
460 f_op = f.file->f_op;
461 mask = DEFAULT_POLLMASK;
462 if (f_op->poll) {
463 wait_key_set(wait, in, out,
464 bit, busy_flag);
465 mask = (*f_op->poll)(f.file, wait);
466 }
467 fdput(f);
468 if ((mask & POLLIN_SET) && (in & bit)) {
469 res_in |= bit;
470 retval++;
471 wait->_qproc = NULL;
472 }
473 if ((mask & POLLOUT_SET) && (out & bit)) {
474 res_out |= bit;
475 retval++;
476 wait->_qproc = NULL;
477 }
478 if ((mask & POLLEX_SET) && (ex & bit)) {
479 res_ex |= bit;
480 retval++;
481 wait->_qproc = NULL;
482 }
483
484 if (retval) {
485 can_busy_loop = false;
486 busy_flag = 0;
487
488
489
490
491
492 } else if (busy_flag & mask)
493 can_busy_loop = true;
494
495 }
496 }
497 if (res_in)
498 *rinp = res_in;
499 if (res_out)
500 *routp = res_out;
501 if (res_ex)
502 *rexp = res_ex;
503 cond_resched();
504 }
505 wait->_qproc = NULL;
506 if (retval || timed_out || signal_pending(current))
507 break;
508 if (table.error) {
509 retval = table.error;
510 break;
511 }
512
513
514 if (can_busy_loop && !need_resched()) {
515 if (!busy_end) {
516 busy_end = busy_loop_end_time();
517 continue;
518 }
519 if (!busy_loop_timeout(busy_end))
520 continue;
521 }
522 busy_flag = 0;
523
524
525
526
527
528
529 if (end_time && !to) {
530 expire = timespec64_to_ktime(*end_time);
531 to = &expire;
532 }
533
534 if (!poll_schedule_timeout(&table, TASK_INTERRUPTIBLE,
535 to, slack))
536 timed_out = 1;
537 }
538
539 poll_freewait(&table);
540
541 return retval;
542}
543
544
545
546
547
548
549
550
551
552int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
553 fd_set __user *exp, struct timespec64 *end_time)
554{
555 fd_set_bits fds;
556 void *bits;
557 int ret, max_fds;
558 size_t size, alloc_size;
559 struct fdtable *fdt;
560
561 long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
562
563 ret = -EINVAL;
564 if (n < 0)
565 goto out_nofds;
566
567
568 rcu_read_lock();
569 fdt = files_fdtable(current->files);
570 max_fds = fdt->max_fds;
571 rcu_read_unlock();
572 if (n > max_fds)
573 n = max_fds;
574
575
576
577
578
579
580 size = FDS_BYTES(n);
581 bits = stack_fds;
582 if (size > sizeof(stack_fds) / 6) {
583
584 ret = -ENOMEM;
585 if (size > (SIZE_MAX / 6))
586 goto out_nofds;
587
588 alloc_size = 6 * size;
589 bits = kmalloc(alloc_size, GFP_KERNEL|__GFP_NOWARN);
590 if (!bits && alloc_size > PAGE_SIZE)
591 bits = vmalloc(alloc_size);
592
593 if (!bits)
594 goto out_nofds;
595 }
596 fds.in = bits;
597 fds.out = bits + size;
598 fds.ex = bits + 2*size;
599 fds.res_in = bits + 3*size;
600 fds.res_out = bits + 4*size;
601 fds.res_ex = bits + 5*size;
602
603 if ((ret = get_fd_set(n, inp, fds.in)) ||
604 (ret = get_fd_set(n, outp, fds.out)) ||
605 (ret = get_fd_set(n, exp, fds.ex)))
606 goto out;
607 zero_fd_set(n, fds.res_in);
608 zero_fd_set(n, fds.res_out);
609 zero_fd_set(n, fds.res_ex);
610
611 ret = do_select(n, &fds, end_time);
612
613 if (ret < 0)
614 goto out;
615 if (!ret) {
616 ret = -ERESTARTNOHAND;
617 if (signal_pending(current))
618 goto out;
619 ret = 0;
620 }
621
622 if (set_fd_set(n, inp, fds.res_in) ||
623 set_fd_set(n, outp, fds.res_out) ||
624 set_fd_set(n, exp, fds.res_ex))
625 ret = -EFAULT;
626
627out:
628 if (bits != stack_fds)
629 kvfree(bits);
630out_nofds:
631 return ret;
632}
633
634SYSCALL_DEFINE5(select, int, n, fd_set __user *, inp, fd_set __user *, outp,
635 fd_set __user *, exp, struct timeval __user *, tvp)
636{
637 struct timespec64 end_time, *to = NULL;
638 struct timeval tv;
639 int ret;
640
641 if (tvp) {
642 if (copy_from_user(&tv, tvp, sizeof(tv)))
643 return -EFAULT;
644
645 to = &end_time;
646 if (poll_select_set_timeout(to,
647 tv.tv_sec + (tv.tv_usec / USEC_PER_SEC),
648 (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC))
649 return -EINVAL;
650 }
651
652 ret = core_sys_select(n, inp, outp, exp, to);
653 ret = poll_select_copy_remaining(&end_time, tvp, 1, ret);
654
655 return ret;
656}
657
658static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp,
659 fd_set __user *exp, struct timespec __user *tsp,
660 const sigset_t __user *sigmask, size_t sigsetsize)
661{
662 sigset_t ksigmask, sigsaved;
663 struct timespec ts;
664 struct timespec64 ts64, end_time, *to = NULL;
665 int ret;
666
667 if (tsp) {
668 if (copy_from_user(&ts, tsp, sizeof(ts)))
669 return -EFAULT;
670 ts64 = timespec_to_timespec64(ts);
671
672 to = &end_time;
673 if (poll_select_set_timeout(to, ts64.tv_sec, ts64.tv_nsec))
674 return -EINVAL;
675 }
676
677 if (sigmask) {
678
679 if (sigsetsize != sizeof(sigset_t))
680 return -EINVAL;
681 if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask)))
682 return -EFAULT;
683
684 sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
685 sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
686 }
687
688 ret = core_sys_select(n, inp, outp, exp, to);
689 ret = poll_select_copy_remaining(&end_time, tsp, 0, ret);
690
691 if (ret == -ERESTARTNOHAND) {
692
693
694
695
696
697 if (sigmask) {
698 memcpy(¤t->saved_sigmask, &sigsaved,
699 sizeof(sigsaved));
700 set_restore_sigmask();
701 }
702 } else if (sigmask)
703 sigprocmask(SIG_SETMASK, &sigsaved, NULL);
704
705 return ret;
706}
707
708
709
710
711
712
713
714SYSCALL_DEFINE6(pselect6, int, n, fd_set __user *, inp, fd_set __user *, outp,
715 fd_set __user *, exp, struct timespec __user *, tsp,
716 void __user *, sig)
717{
718 size_t sigsetsize = 0;
719 sigset_t __user *up = NULL;
720
721 if (sig) {
722 if (!access_ok(VERIFY_READ, sig, sizeof(void *)+sizeof(size_t))
723 || __get_user(up, (sigset_t __user * __user *)sig)
724 || __get_user(sigsetsize,
725 (size_t __user *)(sig+sizeof(void *))))
726 return -EFAULT;
727 }
728
729 return do_pselect(n, inp, outp, exp, tsp, up, sigsetsize);
730}
731
732#ifdef __ARCH_WANT_SYS_OLD_SELECT
733struct sel_arg_struct {
734 unsigned long n;
735 fd_set __user *inp, *outp, *exp;
736 struct timeval __user *tvp;
737};
738
739SYSCALL_DEFINE1(old_select, struct sel_arg_struct __user *, arg)
740{
741 struct sel_arg_struct a;
742
743 if (copy_from_user(&a, arg, sizeof(a)))
744 return -EFAULT;
745 return sys_select(a.n, a.inp, a.outp, a.exp, a.tvp);
746}
747#endif
748
749struct poll_list {
750 struct poll_list *next;
751 int len;
752 struct pollfd entries[0];
753};
754
755#define POLLFD_PER_PAGE ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd))
756
757
758
759
760
761
762
763
764static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait,
765 bool *can_busy_poll,
766 unsigned int busy_flag)
767{
768 unsigned int mask;
769 int fd;
770
771 mask = 0;
772 fd = pollfd->fd;
773 if (fd >= 0) {
774 struct fd f = fdget(fd);
775 mask = POLLNVAL;
776 if (f.file) {
777 mask = DEFAULT_POLLMASK;
778 if (f.file->f_op->poll) {
779 pwait->_key = pollfd->events|POLLERR|POLLHUP;
780 pwait->_key |= busy_flag;
781 mask = f.file->f_op->poll(f.file, pwait);
782 if (mask & busy_flag)
783 *can_busy_poll = true;
784 }
785
786 mask &= pollfd->events | POLLERR | POLLHUP;
787 fdput(f);
788 }
789 }
790 pollfd->revents = mask;
791
792 return mask;
793}
794
795static int do_poll(struct poll_list *list, struct poll_wqueues *wait,
796 struct timespec64 *end_time)
797{
798 poll_table* pt = &wait->pt;
799 ktime_t expire, *to = NULL;
800 int timed_out = 0, count = 0;
801 u64 slack = 0;
802 unsigned int busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0;
803 unsigned long busy_end = 0;
804
805
806 if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
807 pt->_qproc = NULL;
808 timed_out = 1;
809 }
810
811 if (end_time && !timed_out)
812 slack = select_estimate_accuracy(end_time);
813
814 for (;;) {
815 struct poll_list *walk;
816 bool can_busy_loop = false;
817
818 for (walk = list; walk != NULL; walk = walk->next) {
819 struct pollfd * pfd, * pfd_end;
820
821 pfd = walk->entries;
822 pfd_end = pfd + walk->len;
823 for (; pfd != pfd_end; pfd++) {
824
825
826
827
828
829
830
831 if (do_pollfd(pfd, pt, &can_busy_loop,
832 busy_flag)) {
833 count++;
834 pt->_qproc = NULL;
835
836 busy_flag = 0;
837 can_busy_loop = false;
838 }
839 }
840 }
841
842
843
844
845 pt->_qproc = NULL;
846 if (!count) {
847 count = wait->error;
848 if (signal_pending(current))
849 count = -EINTR;
850 }
851 if (count || timed_out)
852 break;
853
854
855 if (can_busy_loop && !need_resched()) {
856 if (!busy_end) {
857 busy_end = busy_loop_end_time();
858 continue;
859 }
860 if (!busy_loop_timeout(busy_end))
861 continue;
862 }
863 busy_flag = 0;
864
865
866
867
868
869
870 if (end_time && !to) {
871 expire = timespec64_to_ktime(*end_time);
872 to = &expire;
873 }
874
875 if (!poll_schedule_timeout(wait, TASK_INTERRUPTIBLE, to, slack))
876 timed_out = 1;
877 }
878 return count;
879}
880
881#define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \
882 sizeof(struct pollfd))
883
884int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,
885 struct timespec64 *end_time)
886{
887 struct poll_wqueues table;
888 int err = -EFAULT, fdcount, len, size;
889
890
891
892 long stack_pps[POLL_STACK_ALLOC/sizeof(long)];
893 struct poll_list *const head = (struct poll_list *)stack_pps;
894 struct poll_list *walk = head;
895 unsigned long todo = nfds;
896
897 if (nfds > rlimit(RLIMIT_NOFILE))
898 return -EINVAL;
899
900 len = min_t(unsigned int, nfds, N_STACK_PPS);
901 for (;;) {
902 walk->next = NULL;
903 walk->len = len;
904 if (!len)
905 break;
906
907 if (copy_from_user(walk->entries, ufds + nfds-todo,
908 sizeof(struct pollfd) * walk->len))
909 goto out_fds;
910
911 todo -= walk->len;
912 if (!todo)
913 break;
914
915 len = min(todo, POLLFD_PER_PAGE);
916 size = sizeof(struct poll_list) + sizeof(struct pollfd) * len;
917 walk = walk->next = kmalloc(size, GFP_KERNEL);
918 if (!walk) {
919 err = -ENOMEM;
920 goto out_fds;
921 }
922 }
923
924 poll_initwait(&table);
925 fdcount = do_poll(head, &table, end_time);
926 poll_freewait(&table);
927
928 for (walk = head; walk; walk = walk->next) {
929 struct pollfd *fds = walk->entries;
930 int j;
931
932 for (j = 0; j < walk->len; j++, ufds++)
933 if (__put_user(fds[j].revents, &ufds->revents))
934 goto out_fds;
935 }
936
937 err = fdcount;
938out_fds:
939 walk = head->next;
940 while (walk) {
941 struct poll_list *pos = walk;
942 walk = walk->next;
943 kfree(pos);
944 }
945
946 return err;
947}
948
949static long do_restart_poll(struct restart_block *restart_block)
950{
951 struct pollfd __user *ufds = restart_block->poll.ufds;
952 int nfds = restart_block->poll.nfds;
953 struct timespec64 *to = NULL, end_time;
954 int ret;
955
956 if (restart_block->poll.has_timeout) {
957 end_time.tv_sec = restart_block->poll.tv_sec;
958 end_time.tv_nsec = restart_block->poll.tv_nsec;
959 to = &end_time;
960 }
961
962 ret = do_sys_poll(ufds, nfds, to);
963
964 if (ret == -EINTR) {
965 restart_block->fn = do_restart_poll;
966 ret = -ERESTART_RESTARTBLOCK;
967 }
968 return ret;
969}
970
971SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds,
972 int, timeout_msecs)
973{
974 struct timespec64 end_time, *to = NULL;
975 int ret;
976
977 if (timeout_msecs >= 0) {
978 to = &end_time;
979 poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC,
980 NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC));
981 }
982
983 ret = do_sys_poll(ufds, nfds, to);
984
985 if (ret == -EINTR) {
986 struct restart_block *restart_block;
987
988 restart_block = ¤t->restart_block;
989 restart_block->fn = do_restart_poll;
990 restart_block->poll.ufds = ufds;
991 restart_block->poll.nfds = nfds;
992
993 if (timeout_msecs >= 0) {
994 restart_block->poll.tv_sec = end_time.tv_sec;
995 restart_block->poll.tv_nsec = end_time.tv_nsec;
996 restart_block->poll.has_timeout = 1;
997 } else
998 restart_block->poll.has_timeout = 0;
999
1000 ret = -ERESTART_RESTARTBLOCK;
1001 }
1002 return ret;
1003}
1004
1005SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds,
1006 struct timespec __user *, tsp, const sigset_t __user *, sigmask,
1007 size_t, sigsetsize)
1008{
1009 sigset_t ksigmask, sigsaved;
1010 struct timespec ts;
1011 struct timespec64 end_time, *to = NULL;
1012 int ret;
1013
1014 if (tsp) {
1015 if (copy_from_user(&ts, tsp, sizeof(ts)))
1016 return -EFAULT;
1017
1018 to = &end_time;
1019 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
1020 return -EINVAL;
1021 }
1022
1023 if (sigmask) {
1024
1025 if (sigsetsize != sizeof(sigset_t))
1026 return -EINVAL;
1027 if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask)))
1028 return -EFAULT;
1029
1030 sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
1031 sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
1032 }
1033
1034 ret = do_sys_poll(ufds, nfds, to);
1035
1036
1037 if (ret == -EINTR) {
1038
1039
1040
1041
1042
1043 if (sigmask) {
1044 memcpy(¤t->saved_sigmask, &sigsaved,
1045 sizeof(sigsaved));
1046 set_restore_sigmask();
1047 }
1048 ret = -ERESTARTNOHAND;
1049 } else if (sigmask)
1050 sigprocmask(SIG_SETMASK, &sigsaved, NULL);
1051
1052 ret = poll_select_copy_remaining(&end_time, tsp, 0, ret);
1053
1054 return ret;
1055}
1056