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ARM: tct_hammer_defconfig: Save defconfig
[linux-2.6/btrfs-unstable.git] / fs / select.c
blobd6c652a31e99d18d2d924af983c11504315af56f
1 /*
2 * This file contains the procedures for the handling of select and poll
3 *
4 * Created for Linux based loosely upon Mathius Lattner's minix
5 * patches by Peter MacDonald. Heavily edited by Linus.
6 *
7 * 4 February 1994
8 * COFF/ELF binary emulation. If the process has the STICKY_TIMEOUTS
9 * flag set in its personality we do *not* modify the given timeout
10 * parameter to reflect time remaining.
11 *
12 * 24 January 2000
13 * Changed sys_poll()/do_poll() to use PAGE_SIZE chunk-based allocation
14 * of fds to overcome nfds < 16390 descriptors limit (Tigran Aivazian).
15 */
16
17 #include <linux/kernel.h>
18 #include <linux/sched/signal.h>
19 #include <linux/sched/rt.h>
20 #include <linux/syscalls.h>
21 #include <linux/export.h>
22 #include <linux/slab.h>
23 #include <linux/poll.h>
24 #include <linux/personality.h> /* for STICKY_TIMEOUTS */
25 #include <linux/file.h>
26 #include <linux/fdtable.h>
27 #include <linux/fs.h>
28 #include <linux/rcupdate.h>
29 #include <linux/hrtimer.h>
30 #include <linux/freezer.h>
31 #include <net/busy_poll.h>
32 #include <linux/vmalloc.h>
33
34 #include <linux/uaccess.h>
35
36
37 /*
38 * Estimate expected accuracy in ns from a timeval.
39 *
40 * After quite a bit of churning around, we've settled on
41 * a simple thing of taking 0.1% of the timeout as the
42 * slack, with a cap of 100 msec.
43 * "nice" tasks get a 0.5% slack instead.
44 *
45 * Consider this comment an open invitation to come up with even
46 * better solutions..
47 */
48
49 #define MAX_SLACK (100 * NSEC_PER_MSEC)
50
51 static long __estimate_accuracy(struct timespec64 *tv)
52 {
53 long slack;
54 int divfactor = 1000;
55
56 if (tv->tv_sec < 0)
57 return 0;
58
59 if (task_nice(current) > 0)
60 divfactor = divfactor / 5;
61
62 if (tv->tv_sec > MAX_SLACK / (NSEC_PER_SEC/divfactor))
63 return MAX_SLACK;
64
65 slack = tv->tv_nsec / divfactor;
66 slack += tv->tv_sec * (NSEC_PER_SEC/divfactor);
67
68 if (slack > MAX_SLACK)
69 return MAX_SLACK;
70
71 return slack;
72 }
73
74 u64 select_estimate_accuracy(struct timespec64 *tv)
75 {
76 u64 ret;
77 struct timespec64 now;
78
79 /*
80 * Realtime tasks get a slack of 0 for obvious reasons.
81 */
82
83 if (rt_task(current))
84 return 0;
85
86 ktime_get_ts64(&now);
87 now = timespec64_sub(*tv, now);
88 ret = __estimate_accuracy(&now);
89 if (ret < current->timer_slack_ns)
90 return current->timer_slack_ns;
91 return ret;
92 }
93
94
95
96 struct poll_table_page {
97 struct poll_table_page * next;
98 struct poll_table_entry * entry;
99 struct poll_table_entry entries[0];
100 };
101
102 #define POLL_TABLE_FULL(table) \
103 ((unsigned long)((table)->entry+1) > PAGE_SIZE + (unsigned long)(table))
104
105 /*
106 * Ok, Peter made a complicated, but straightforward multiple_wait() function.
107 * I have rewritten this, taking some shortcuts: This code may not be easy to
108 * follow, but it should be free of race-conditions, and it's practical. If you
109 * understand what I'm doing here, then you understand how the linux
110 * sleep/wakeup mechanism works.
111 *
112 * Two very simple procedures, poll_wait() and poll_freewait() make all the
113 * work. poll_wait() is an inline-function defined in <linux/poll.h>,
114 * as all select/poll functions have to call it to add an entry to the
115 * poll table.
116 */
117 static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
118 poll_table *p);
119
120 void poll_initwait(struct poll_wqueues *pwq)
121 {
122 init_poll_funcptr(&pwq->pt, __pollwait);
123 pwq->polling_task = current;
124 pwq->triggered = 0;
125 pwq->error = 0;
126 pwq->table = NULL;
127 pwq->inline_index = 0;
128 }
129 EXPORT_SYMBOL(poll_initwait);
130
131 static void free_poll_entry(struct poll_table_entry *entry)
132 {
133 remove_wait_queue(entry->wait_address, &entry->wait);
134 fput(entry->filp);
135 }
136
137 void poll_freewait(struct poll_wqueues *pwq)
138 {
139 struct poll_table_page * p = pwq->table;
140 int i;
141 for (i = 0; i < pwq->inline_index; i++)
142 free_poll_entry(pwq->inline_entries + i);
143 while (p) {
144 struct poll_table_entry * entry;
145 struct poll_table_page *old;
146
147 entry = p->entry;
148 do {
149 entry--;
150 free_poll_entry(entry);
151 } while (entry > p->entries);
152 old = p;
153 p = p->next;
154 free_page((unsigned long) old);
155 }
156 }
157 EXPORT_SYMBOL(poll_freewait);
158
159 static struct poll_table_entry *poll_get_entry(struct poll_wqueues *p)
160 {
161 struct poll_table_page *table = p->table;
162
163 if (p->inline_index < N_INLINE_POLL_ENTRIES)
164 return p->inline_entries + p->inline_index++;
165
166 if (!table || POLL_TABLE_FULL(table)) {
167 struct poll_table_page *new_table;
168
169 new_table = (struct poll_table_page *) __get_free_page(GFP_KERNEL);
170 if (!new_table) {
171 p->error = -ENOMEM;
172 return NULL;
173 }
174 new_table->entry = new_table->entries;
175 new_table->next = table;
176 p->table = new_table;
177 table = new_table;
178 }
179
180 return table->entry++;
181 }
182
183 static int __pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key)
184 {
185 struct poll_wqueues *pwq = wait->private;
186 DECLARE_WAITQUEUE(dummy_wait, pwq->polling_task);
187
188 /*
189 * Although this function is called under waitqueue lock, LOCK
190 * doesn't imply write barrier and the users expect write
191 * barrier semantics on wakeup functions. The following
192 * smp_wmb() is equivalent to smp_wmb() in try_to_wake_up()
193 * and is paired with smp_store_mb() in poll_schedule_timeout.
194 */
195 smp_wmb();
196 pwq->triggered = 1;
197
198 /*
199 * Perform the default wake up operation using a dummy
200 * waitqueue.
201 *
202 * TODO: This is hacky but there currently is no interface to
203 * pass in @sync. @sync is scheduled to be removed and once
204 * that happens, wake_up_process() can be used directly.
205 */
206 return default_wake_function(&dummy_wait, mode, sync, key);
207 }
208
209 static int pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key)
210 {
211 struct poll_table_entry *entry;
212
213 entry = container_of(wait, struct poll_table_entry, wait);
214 if (key && !((unsigned long)key & entry->key))
215 return 0;
216 return __pollwake(wait, mode, sync, key);
217 }
218
219 /* Add a new entry */
220 static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
221 poll_table *p)
222 {
223 struct poll_wqueues *pwq = container_of(p, struct poll_wqueues, pt);
224 struct poll_table_entry *entry = poll_get_entry(pwq);
225 if (!entry)
226 return;
227 entry->filp = get_file(filp);
228 entry->wait_address = wait_address;
229 entry->key = p->_key;
230 init_waitqueue_func_entry(&entry->wait, pollwake);
231 entry->wait.private = pwq;
232 add_wait_queue(wait_address, &entry->wait);
233 }
234
235 int poll_schedule_timeout(struct poll_wqueues *pwq, int state,
236 ktime_t *expires, unsigned long slack)
237 {
238 int rc = -EINTR;
239
240 set_current_state(state);
241 if (!pwq->triggered)
242 rc = schedule_hrtimeout_range(expires, slack, HRTIMER_MODE_ABS);
243 __set_current_state(TASK_RUNNING);
244
245 /*
246 * Prepare for the next iteration.
247 *
248 * The following smp_store_mb() serves two purposes. First, it's
249 * the counterpart rmb of the wmb in pollwake() such that data
250 * written before wake up is always visible after wake up.
251 * Second, the full barrier guarantees that triggered clearing
252 * doesn't pass event check of the next iteration. Note that
253 * this problem doesn't exist for the first iteration as
254 * add_wait_queue() has full barrier semantics.
255 */
256 smp_store_mb(pwq->triggered, 0);
257
258 return rc;
259 }
260 EXPORT_SYMBOL(poll_schedule_timeout);
261
262 /**
263 * poll_select_set_timeout - helper function to setup the timeout value
264 * @to: pointer to timespec64 variable for the final timeout
265 * @sec: seconds (from user space)
266 * @nsec: nanoseconds (from user space)
267 *
268 * Note, we do not use a timespec for the user space value here, That
269 * way we can use the function for timeval and compat interfaces as well.
270 *
271 * Returns -EINVAL if sec/nsec are not normalized. Otherwise 0.
272 */
273 int poll_select_set_timeout(struct timespec64 *to, time64_t sec, long nsec)
274 {
275 struct timespec64 ts = {.tv_sec = sec, .tv_nsec = nsec};
276
277 if (!timespec64_valid(&ts))
278 return -EINVAL;
279
280 /* Optimize for the zero timeout value here */
281 if (!sec && !nsec) {
282 to->tv_sec = to->tv_nsec = 0;
283 } else {
284 ktime_get_ts64(to);
285 *to = timespec64_add_safe(*to, ts);
286 }
287 return 0;
288 }
289
290 static int poll_select_copy_remaining(struct timespec64 *end_time,
291 void __user *p,
292 int timeval, int ret)
293 {
294 struct timespec64 rts64;
295 struct timespec rts;
296 struct timeval rtv;
297
298 if (!p)
299 return ret;
300
301 if (current->personality & STICKY_TIMEOUTS)
302 goto sticky;
303
304 /* No update for zero timeout */
305 if (!end_time->tv_sec && !end_time->tv_nsec)
306 return ret;
307
308 ktime_get_ts64(&rts64);
309 rts64 = timespec64_sub(*end_time, rts64);
310 if (rts64.tv_sec < 0)
311 rts64.tv_sec = rts64.tv_nsec = 0;
312
313 rts = timespec64_to_timespec(rts64);
314
315 if (timeval) {
316 if (sizeof(rtv) > sizeof(rtv.tv_sec) + sizeof(rtv.tv_usec))
317 memset(&rtv, 0, sizeof(rtv));
318 rtv.tv_sec = rts64.tv_sec;
319 rtv.tv_usec = rts64.tv_nsec / NSEC_PER_USEC;
320
321 if (!copy_to_user(p, &rtv, sizeof(rtv)))
322 return ret;
323
324 } else if (!copy_to_user(p, &rts, sizeof(rts)))
325 return ret;
326
327 /*
328 * If an application puts its timeval in read-only memory, we
329 * don't want the Linux-specific update to the timeval to
330 * cause a fault after the select has completed
331 * successfully. However, because we're not updating the
332 * timeval, we can't restart the system call.
333 */
334
335 sticky:
336 if (ret == -ERESTARTNOHAND)
337 ret = -EINTR;
338 return ret;
339 }
340
341 /*
342 * Scalable version of the fd_set.
343 */
344
345 typedef struct {
346 unsigned long *in, *out, *ex;
347 unsigned long *res_in, *res_out, *res_ex;
348 } fd_set_bits;
349
350 /*
351 * How many longwords for "nr" bits?
352 */
353 #define FDS_BITPERLONG (8*sizeof(long))
354 #define FDS_LONGS(nr) (((nr)+FDS_BITPERLONG-1)/FDS_BITPERLONG)
355 #define FDS_BYTES(nr) (FDS_LONGS(nr)*sizeof(long))
356
357 /*
358 * We do a VERIFY_WRITE here even though we are only reading this time:
359 * we'll write to it eventually..
360 *
361 * Use "unsigned long" accesses to let user-mode fd_set's be long-aligned.
362 */
363 static inline
364 int get_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
365 {
366 nr = FDS_BYTES(nr);
367 if (ufdset)
368 return copy_from_user(fdset, ufdset, nr) ? -EFAULT : 0;
369
370 memset(fdset, 0, nr);
371 return 0;
372 }
373
374 static inline unsigned long __must_check
375 set_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
376 {
377 if (ufdset)
378 return __copy_to_user(ufdset, fdset, FDS_BYTES(nr));
379 return 0;
380 }
381
382 static inline
383 void zero_fd_set(unsigned long nr, unsigned long *fdset)
384 {
385 memset(fdset, 0, FDS_BYTES(nr));
386 }
387
388 #define FDS_IN(fds, n) (fds->in + n)
389 #define FDS_OUT(fds, n) (fds->out + n)
390 #define FDS_EX(fds, n) (fds->ex + n)
391
392 #define BITS(fds, n) (*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n))
393
394 static int max_select_fd(unsigned long n, fd_set_bits *fds)
395 {
396 unsigned long *open_fds;
397 unsigned long set;
398 int max;
399 struct fdtable *fdt;
400
401 /* handle last in-complete long-word first */
402 set = ~(~0UL << (n & (BITS_PER_LONG-1)));
403 n /= BITS_PER_LONG;
404 fdt = files_fdtable(current->files);
405 open_fds = fdt->open_fds + n;
406 max = 0;
407 if (set) {
408 set &= BITS(fds, n);
409 if (set) {
410 if (!(set & ~*open_fds))
411 goto get_max;
412 return -EBADF;
413 }
414 }
415 while (n) {
416 open_fds--;
417 n--;
418 set = BITS(fds, n);
419 if (!set)
420 continue;
421 if (set & ~*open_fds)
422 return -EBADF;
423 if (max)
424 continue;
425 get_max:
426 do {
427 max++;
428 set >>= 1;
429 } while (set);
430 max += n * BITS_PER_LONG;
431 }
432
433 return max;
434 }
435
436 #define POLLIN_SET (POLLRDNORM | POLLRDBAND | POLLIN | POLLHUP | POLLERR)
437 #define POLLOUT_SET (POLLWRBAND | POLLWRNORM | POLLOUT | POLLERR)
438 #define POLLEX_SET (POLLPRI)
439
440 static inline void wait_key_set(poll_table *wait, unsigned long in,
441 unsigned long out, unsigned long bit,
442 unsigned int ll_flag)
443 {
444 wait->_key = POLLEX_SET | ll_flag;
445 if (in & bit)
446 wait->_key |= POLLIN_SET;
447 if (out & bit)
448 wait->_key |= POLLOUT_SET;
449 }
450
451 static int do_select(int n, fd_set_bits *fds, struct timespec64 *end_time)
452 {
453 ktime_t expire, *to = NULL;
454 struct poll_wqueues table;
455 poll_table *wait;
456 int retval, i, timed_out = 0;
457 u64 slack = 0;
458 unsigned int busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0;
459 unsigned long busy_start = 0;
460
461 rcu_read_lock();
462 retval = max_select_fd(n, fds);
463 rcu_read_unlock();
464
465 if (retval < 0)
466 return retval;
467 n = retval;
468
469 poll_initwait(&table);
470 wait = &table.pt;
471 if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
472 wait->_qproc = NULL;
473 timed_out = 1;
474 }
475
476 if (end_time && !timed_out)
477 slack = select_estimate_accuracy(end_time);
478
479 retval = 0;
480 for (;;) {
481 unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp;
482 bool can_busy_loop = false;
483
484 inp = fds->in; outp = fds->out; exp = fds->ex;
485 rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex;
486
487 for (i = 0; i < n; ++rinp, ++routp, ++rexp) {
488 unsigned long in, out, ex, all_bits, bit = 1, mask, j;
489 unsigned long res_in = 0, res_out = 0, res_ex = 0;
490
491 in = *inp++; out = *outp++; ex = *exp++;
492 all_bits = in | out | ex;
493 if (all_bits == 0) {
494 i += BITS_PER_LONG;
495 continue;
496 }
497
498 for (j = 0; j < BITS_PER_LONG; ++j, ++i, bit <<= 1) {
499 struct fd f;
500 if (i >= n)
501 break;
502 if (!(bit & all_bits))
503 continue;
504 f = fdget(i);
505 if (f.file) {
506 const struct file_operations *f_op;
507 f_op = f.file->f_op;
508 mask = DEFAULT_POLLMASK;
509 if (f_op->poll) {
510 wait_key_set(wait, in, out,
511 bit, busy_flag);
512 mask = (*f_op->poll)(f.file, wait);
513 }
514 fdput(f);
515 if ((mask & POLLIN_SET) && (in & bit)) {
516 res_in |= bit;
517 retval++;
518 wait->_qproc = NULL;
519 }
520 if ((mask & POLLOUT_SET) && (out & bit)) {
521 res_out |= bit;
522 retval++;
523 wait->_qproc = NULL;
524 }
525 if ((mask & POLLEX_SET) && (ex & bit)) {
526 res_ex |= bit;
527 retval++;
528 wait->_qproc = NULL;
529 }
530 /* got something, stop busy polling */
531 if (retval) {
532 can_busy_loop = false;
533 busy_flag = 0;
534
535 /*
536 * only remember a returned
537 * POLL_BUSY_LOOP if we asked for it
538 */
539 } else if (busy_flag & mask)
540 can_busy_loop = true;
541
542 }
543 }
544 if (res_in)
545 *rinp = res_in;
546 if (res_out)
547 *routp = res_out;
548 if (res_ex)
549 *rexp = res_ex;
550 cond_resched();
551 }
552 wait->_qproc = NULL;
553 if (retval || timed_out || signal_pending(current))
554 break;
555 if (table.error) {
556 retval = table.error;
557 break;
558 }
559
560 /* only if found POLL_BUSY_LOOP sockets && not out of time */
561 if (can_busy_loop && !need_resched()) {
562 if (!busy_start) {
563 busy_start = busy_loop_current_time();
564 continue;
565 }
566 if (!busy_loop_timeout(busy_start))
567 continue;
568 }
569 busy_flag = 0;
570
571 /*
572 * If this is the first loop and we have a timeout
573 * given, then we convert to ktime_t and set the to
574 * pointer to the expiry value.
575 */
576 if (end_time && !to) {
577 expire = timespec64_to_ktime(*end_time);
578 to = &expire;
579 }
580
581 if (!poll_schedule_timeout(&table, TASK_INTERRUPTIBLE,
582 to, slack))
583 timed_out = 1;
584 }
585
586 poll_freewait(&table);
587
588 return retval;
589 }
590
591 /*
592 * We can actually return ERESTARTSYS instead of EINTR, but I'd
593 * like to be certain this leads to no problems. So I return
594 * EINTR just for safety.
595 *
596 * Update: ERESTARTSYS breaks at least the xview clock binary, so
597 * I'm trying ERESTARTNOHAND which restart only when you want to.
598 */
599 int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
600 fd_set __user *exp, struct timespec64 *end_time)
601 {
602 fd_set_bits fds;
603 void *bits;
604 int ret, max_fds;
605 size_t size, alloc_size;
606 struct fdtable *fdt;
607 /* Allocate small arguments on the stack to save memory and be faster */
608 long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
609
610 ret = -EINVAL;
611 if (n < 0)
612 goto out_nofds;
613
614 /* max_fds can increase, so grab it once to avoid race */
615 rcu_read_lock();
616 fdt = files_fdtable(current->files);
617 max_fds = fdt->max_fds;
618 rcu_read_unlock();
619 if (n > max_fds)
620 n = max_fds;
621
622 /*
623 * We need 6 bitmaps (in/out/ex for both incoming and outgoing),
624 * since we used fdset we need to allocate memory in units of
625 * long-words.
626 */
627 size = FDS_BYTES(n);
628 bits = stack_fds;
629 if (size > sizeof(stack_fds) / 6) {
630 /* Not enough space in on-stack array; must use kmalloc */
631 ret = -ENOMEM;
632 if (size > (SIZE_MAX / 6))
633 goto out_nofds;
634
635 alloc_size = 6 * size;
636 bits = kvmalloc(alloc_size, GFP_KERNEL);
637 if (!bits)
638 goto out_nofds;
639 }
640 fds.in = bits;
641 fds.out = bits + size;
642 fds.ex = bits + 2*size;
643 fds.res_in = bits + 3*size;
644 fds.res_out = bits + 4*size;
645 fds.res_ex = bits + 5*size;
646
647 if ((ret = get_fd_set(n, inp, fds.in)) ||
648 (ret = get_fd_set(n, outp, fds.out)) ||
649 (ret = get_fd_set(n, exp, fds.ex)))
650 goto out;
651 zero_fd_set(n, fds.res_in);
652 zero_fd_set(n, fds.res_out);
653 zero_fd_set(n, fds.res_ex);
654
655 ret = do_select(n, &fds, end_time);
656
657 if (ret < 0)
658 goto out;
659 if (!ret) {
660 ret = -ERESTARTNOHAND;
661 if (signal_pending(current))
662 goto out;
663 ret = 0;
664 }
665
666 if (set_fd_set(n, inp, fds.res_in) ||
667 set_fd_set(n, outp, fds.res_out) ||
668 set_fd_set(n, exp, fds.res_ex))
669 ret = -EFAULT;
670
671 out:
672 if (bits != stack_fds)
673 kvfree(bits);
674 out_nofds:
675 return ret;
676 }
677
678 SYSCALL_DEFINE5(select, int, n, fd_set __user *, inp, fd_set __user *, outp,
679 fd_set __user *, exp, struct timeval __user *, tvp)
680 {
681 struct timespec64 end_time, *to = NULL;
682 struct timeval tv;
683 int ret;
684
685 if (tvp) {
686 if (copy_from_user(&tv, tvp, sizeof(tv)))
687 return -EFAULT;
688
689 to = &end_time;
690 if (poll_select_set_timeout(to,
691 tv.tv_sec + (tv.tv_usec / USEC_PER_SEC),
692 (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC))
693 return -EINVAL;
694 }
695
696 ret = core_sys_select(n, inp, outp, exp, to);
697 ret = poll_select_copy_remaining(&end_time, tvp, 1, ret);
698
699 return ret;
700 }
701
702 static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp,
703 fd_set __user *exp, struct timespec __user *tsp,
704 const sigset_t __user *sigmask, size_t sigsetsize)
705 {
706 sigset_t ksigmask, sigsaved;
707 struct timespec ts;
708 struct timespec64 ts64, end_time, *to = NULL;
709 int ret;
710
711 if (tsp) {
712 if (copy_from_user(&ts, tsp, sizeof(ts)))
713 return -EFAULT;
714 ts64 = timespec_to_timespec64(ts);
715
716 to = &end_time;
717 if (poll_select_set_timeout(to, ts64.tv_sec, ts64.tv_nsec))
718 return -EINVAL;
719 }
720
721 if (sigmask) {
722 /* XXX: Don't preclude handling different sized sigset_t's. */
723 if (sigsetsize != sizeof(sigset_t))
724 return -EINVAL;
725 if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask)))
726 return -EFAULT;
727
728 sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
729 sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
730 }
731
732 ret = core_sys_select(n, inp, outp, exp, to);
733 ret = poll_select_copy_remaining(&end_time, tsp, 0, ret);
734
735 if (ret == -ERESTARTNOHAND) {
736 /*
737 * Don't restore the signal mask yet. Let do_signal() deliver
738 * the signal on the way back to userspace, before the signal
739 * mask is restored.
740 */
741 if (sigmask) {
742 memcpy(&current->saved_sigmask, &sigsaved,
743 sizeof(sigsaved));
744 set_restore_sigmask();
745 }
746 } else if (sigmask)
747 sigprocmask(SIG_SETMASK, &sigsaved, NULL);
748
749 return ret;
750 }
751
752 /*
753 * Most architectures can't handle 7-argument syscalls. So we provide a
754 * 6-argument version where the sixth argument is a pointer to a structure
755 * which has a pointer to the sigset_t itself followed by a size_t containing
756 * the sigset size.
757 */
758 SYSCALL_DEFINE6(pselect6, int, n, fd_set __user *, inp, fd_set __user *, outp,
759 fd_set __user *, exp, struct timespec __user *, tsp,
760 void __user *, sig)
761 {
762 size_t sigsetsize = 0;
763 sigset_t __user *up = NULL;
764
765 if (sig) {
766 if (!access_ok(VERIFY_READ, sig, sizeof(void *)+sizeof(size_t))
767 || __get_user(up, (sigset_t __user * __user *)sig)
768 || __get_user(sigsetsize,
769 (size_t __user *)(sig+sizeof(void *))))
770 return -EFAULT;
771 }
772
773 return do_pselect(n, inp, outp, exp, tsp, up, sigsetsize);
774 }
775
776 #ifdef __ARCH_WANT_SYS_OLD_SELECT
777 struct sel_arg_struct {
778 unsigned long n;
779 fd_set __user *inp, *outp, *exp;
780 struct timeval __user *tvp;
781 };
782
783 SYSCALL_DEFINE1(old_select, struct sel_arg_struct __user *, arg)
784 {
785 struct sel_arg_struct a;
786
787 if (copy_from_user(&a, arg, sizeof(a)))
788 return -EFAULT;
789 return sys_select(a.n, a.inp, a.outp, a.exp, a.tvp);
790 }
791 #endif
792
793 struct poll_list {
794 struct poll_list *next;
795 int len;
796 struct pollfd entries[0];
797 };
798
799 #define POLLFD_PER_PAGE ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd))
800
801 /*
802 * Fish for pollable events on the pollfd->fd file descriptor. We're only
803 * interested in events matching the pollfd->events mask, and the result
804 * matching that mask is both recorded in pollfd->revents and returned. The
805 * pwait poll_table will be used by the fd-provided poll handler for waiting,
806 * if pwait->_qproc is non-NULL.
807 */
808 static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait,
809 bool *can_busy_poll,
810 unsigned int busy_flag)
811 {
812 unsigned int mask;
813 int fd;
814
815 mask = 0;
816 fd = pollfd->fd;
817 if (fd >= 0) {
818 struct fd f = fdget(fd);
819 mask = POLLNVAL;
820 if (f.file) {
821 mask = DEFAULT_POLLMASK;
822 if (f.file->f_op->poll) {
823 pwait->_key = pollfd->events|POLLERR|POLLHUP;
824 pwait->_key |= busy_flag;
825 mask = f.file->f_op->poll(f.file, pwait);
826 if (mask & busy_flag)
827 *can_busy_poll = true;
828 }
829 /* Mask out unneeded events. */
830 mask &= pollfd->events | POLLERR | POLLHUP;
831 fdput(f);
832 }
833 }
834 pollfd->revents = mask;
835
836 return mask;
837 }
838
839 static int do_poll(struct poll_list *list, struct poll_wqueues *wait,
840 struct timespec64 *end_time)
841 {
842 poll_table* pt = &wait->pt;
843 ktime_t expire, *to = NULL;
844 int timed_out = 0, count = 0;
845 u64 slack = 0;
846 unsigned int busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0;
847 unsigned long busy_start = 0;
848
849 /* Optimise the no-wait case */
850 if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
851 pt->_qproc = NULL;
852 timed_out = 1;
853 }
854
855 if (end_time && !timed_out)
856 slack = select_estimate_accuracy(end_time);
857
858 for (;;) {
859 struct poll_list *walk;
860 bool can_busy_loop = false;
861
862 for (walk = list; walk != NULL; walk = walk->next) {
863 struct pollfd * pfd, * pfd_end;
864
865 pfd = walk->entries;
866 pfd_end = pfd + walk->len;
867 for (; pfd != pfd_end; pfd++) {
868 /*
869 * Fish for events. If we found one, record it
870 * and kill poll_table->_qproc, so we don't
871 * needlessly register any other waiters after
872 * this. They'll get immediately deregistered
873 * when we break out and return.
874 */
875 if (do_pollfd(pfd, pt, &can_busy_loop,
876 busy_flag)) {
877 count++;
878 pt->_qproc = NULL;
879 /* found something, stop busy polling */
880 busy_flag = 0;
881 can_busy_loop = false;
882 }
883 }
884 }
885 /*
886 * All waiters have already been registered, so don't provide
887 * a poll_table->_qproc to them on the next loop iteration.
888 */
889 pt->_qproc = NULL;
890 if (!count) {
891 count = wait->error;
892 if (signal_pending(current))
893 count = -EINTR;
894 }
895 if (count || timed_out)
896 break;
897
898 /* only if found POLL_BUSY_LOOP sockets && not out of time */
899 if (can_busy_loop && !need_resched()) {
900 if (!busy_start) {
901 busy_start = busy_loop_current_time();
902 continue;
903 }
904 if (!busy_loop_timeout(busy_start))
905 continue;
906 }
907 busy_flag = 0;
908
909 /*
910 * If this is the first loop and we have a timeout
911 * given, then we convert to ktime_t and set the to
912 * pointer to the expiry value.
913 */
914 if (end_time && !to) {
915 expire = timespec64_to_ktime(*end_time);
916 to = &expire;
917 }
918
919 if (!poll_schedule_timeout(wait, TASK_INTERRUPTIBLE, to, slack))
920 timed_out = 1;
921 }
922 return count;
923 }
924
925 #define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \
926 sizeof(struct pollfd))
927
928 static int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,
929 struct timespec64 *end_time)
930 {
931 struct poll_wqueues table;
932 int err = -EFAULT, fdcount, len, size;
933 /* Allocate small arguments on the stack to save memory and be
934 faster - use long to make sure the buffer is aligned properly
935 on 64 bit archs to avoid unaligned access */
936 long stack_pps[POLL_STACK_ALLOC/sizeof(long)];
937 struct poll_list *const head = (struct poll_list *)stack_pps;
938 struct poll_list *walk = head;
939 unsigned long todo = nfds;
940
941 if (nfds > rlimit(RLIMIT_NOFILE))
942 return -EINVAL;
943
944 len = min_t(unsigned int, nfds, N_STACK_PPS);
945 for (;;) {
946 walk->next = NULL;
947 walk->len = len;
948 if (!len)
949 break;
950
951 if (copy_from_user(walk->entries, ufds + nfds-todo,
952 sizeof(struct pollfd) * walk->len))
953 goto out_fds;
954
955 todo -= walk->len;
956 if (!todo)
957 break;
958
959 len = min(todo, POLLFD_PER_PAGE);
960 size = sizeof(struct poll_list) + sizeof(struct pollfd) * len;
961 walk = walk->next = kmalloc(size, GFP_KERNEL);
962 if (!walk) {
963 err = -ENOMEM;
964 goto out_fds;
965 }
966 }
967
968 poll_initwait(&table);
969 fdcount = do_poll(head, &table, end_time);
970 poll_freewait(&table);
971
972 for (walk = head; walk; walk = walk->next) {
973 struct pollfd *fds = walk->entries;
974 int j;
975
976 for (j = 0; j < walk->len; j++, ufds++)
977 if (__put_user(fds[j].revents, &ufds->revents))
978 goto out_fds;
979 }
980
981 err = fdcount;
982 out_fds:
983 walk = head->next;
984 while (walk) {
985 struct poll_list *pos = walk;
986 walk = walk->next;
987 kfree(pos);
988 }
989
990 return err;
991 }
992
993 static long do_restart_poll(struct restart_block *restart_block)
994 {
995 struct pollfd __user *ufds = restart_block->poll.ufds;
996 int nfds = restart_block->poll.nfds;
997 struct timespec64 *to = NULL, end_time;
998 int ret;
999
1000 if (restart_block->poll.has_timeout) {
1001 end_time.tv_sec = restart_block->poll.tv_sec;
1002 end_time.tv_nsec = restart_block->poll.tv_nsec;
1003 to = &end_time;
1004 }
1005
1006 ret = do_sys_poll(ufds, nfds, to);
1007
1008 if (ret == -EINTR) {
1009 restart_block->fn = do_restart_poll;
1010 ret = -ERESTART_RESTARTBLOCK;
1011 }
1012 return ret;
1013 }
1014
1015 SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds,
1016 int, timeout_msecs)
1017 {
1018 struct timespec64 end_time, *to = NULL;
1019 int ret;
1020
1021 if (timeout_msecs >= 0) {
1022 to = &end_time;
1023 poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC,
1024 NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC));
1025 }
1026
1027 ret = do_sys_poll(ufds, nfds, to);
1028
1029 if (ret == -EINTR) {
1030 struct restart_block *restart_block;
1031
1032 restart_block = &current->restart_block;
1033 restart_block->fn = do_restart_poll;
1034 restart_block->poll.ufds = ufds;
1035 restart_block->poll.nfds = nfds;
1036
1037 if (timeout_msecs >= 0) {
1038 restart_block->poll.tv_sec = end_time.tv_sec;
1039 restart_block->poll.tv_nsec = end_time.tv_nsec;
1040 restart_block->poll.has_timeout = 1;
1041 } else
1042 restart_block->poll.has_timeout = 0;
1043
1044 ret = -ERESTART_RESTARTBLOCK;
1045 }
1046 return ret;
1047 }
1048
1049 SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds,
1050 struct timespec __user *, tsp, const sigset_t __user *, sigmask,
1051 size_t, sigsetsize)
1052 {
1053 sigset_t ksigmask, sigsaved;
1054 struct timespec ts;
1055 struct timespec64 end_time, *to = NULL;
1056 int ret;
1057
1058 if (tsp) {
1059 if (copy_from_user(&ts, tsp, sizeof(ts)))
1060 return -EFAULT;
1061
1062 to = &end_time;
1063 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
1064 return -EINVAL;
1065 }
1066
1067 if (sigmask) {
1068 /* XXX: Don't preclude handling different sized sigset_t's. */
1069 if (sigsetsize != sizeof(sigset_t))
1070 return -EINVAL;
1071 if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask)))
1072 return -EFAULT;
1073
1074 sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
1075 sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
1076 }
1077
1078 ret = do_sys_poll(ufds, nfds, to);
1079
1080 /* We can restart this syscall, usually */
1081 if (ret == -EINTR) {
1082 /*
1083 * Don't restore the signal mask yet. Let do_signal() deliver
1084 * the signal on the way back to userspace, before the signal
1085 * mask is restored.
1086 */
1087 if (sigmask) {
1088 memcpy(&current->saved_sigmask, &sigsaved,
1089 sizeof(sigsaved));
1090 set_restore_sigmask();
1091 }
1092 ret = -ERESTARTNOHAND;
1093 } else if (sigmask)
1094 sigprocmask(SIG_SETMASK, &sigsaved, NULL);
1095
1096 ret = poll_select_copy_remaining(&end_time, tsp, 0, ret);
1097
1098 return ret;
1099 }
1100
1101 #ifdef CONFIG_COMPAT
1102 #define __COMPAT_NFDBITS (8 * sizeof(compat_ulong_t))
1103
1104 static
1105 int compat_poll_select_copy_remaining(struct timespec *end_time, void __user *p,
1106 int timeval, int ret)
1107 {
1108 struct timespec ts;
1109
1110 if (!p)
1111 return ret;
1112
1113 if (current->personality & STICKY_TIMEOUTS)
1114 goto sticky;
1115
1116 /* No update for zero timeout */
1117 if (!end_time->tv_sec && !end_time->tv_nsec)
1118 return ret;
1119
1120 ktime_get_ts(&ts);
1121 ts = timespec_sub(*end_time, ts);
1122 if (ts.tv_sec < 0)
1123 ts.tv_sec = ts.tv_nsec = 0;
1124
1125 if (timeval) {
1126 struct compat_timeval rtv;
1127
1128 rtv.tv_sec = ts.tv_sec;
1129 rtv.tv_usec = ts.tv_nsec / NSEC_PER_USEC;
1130
1131 if (!copy_to_user(p, &rtv, sizeof(rtv)))
1132 return ret;
1133 } else {
1134 struct compat_timespec rts;
1135
1136 rts.tv_sec = ts.tv_sec;
1137 rts.tv_nsec = ts.tv_nsec;
1138
1139 if (!copy_to_user(p, &rts, sizeof(rts)))
1140 return ret;
1141 }
1142 /*
1143 * If an application puts its timeval in read-only memory, we
1144 * don't want the Linux-specific update to the timeval to
1145 * cause a fault after the select has completed
1146 * successfully. However, because we're not updating the
1147 * timeval, we can't restart the system call.
1148 */
1149
1150 sticky:
1151 if (ret == -ERESTARTNOHAND)
1152 ret = -EINTR;
1153 return ret;
1154 }
1155
1156 /*
1157 * Ooo, nasty. We need here to frob 32-bit unsigned longs to
1158 * 64-bit unsigned longs.
1159 */
1160 static
1161 int compat_get_fd_set(unsigned long nr, compat_ulong_t __user *ufdset,
1162 unsigned long *fdset)
1163 {
1164 nr = DIV_ROUND_UP(nr, __COMPAT_NFDBITS);
1165 if (ufdset) {
1166 unsigned long odd;
1167
1168 if (!access_ok(VERIFY_WRITE, ufdset, nr*sizeof(compat_ulong_t)))
1169 return -EFAULT;
1170
1171 odd = nr & 1UL;
1172 nr &= ~1UL;
1173 while (nr) {
1174 unsigned long h, l;
1175 if (__get_user(l, ufdset) || __get_user(h, ufdset+1))
1176 return -EFAULT;
1177 ufdset += 2;
1178 *fdset++ = h << 32 | l;
1179 nr -= 2;
1180 }
1181 if (odd && __get_user(*fdset, ufdset))
1182 return -EFAULT;
1183 } else {
1184 /* Tricky, must clear full unsigned long in the
1185 * kernel fdset at the end, this makes sure that
1186 * actually happens.
1187 */
1188 memset(fdset, 0, ((nr + 1) & ~1)*sizeof(compat_ulong_t));
1189 }
1190 return 0;
1191 }
1192
1193 static
1194 int compat_set_fd_set(unsigned long nr, compat_ulong_t __user *ufdset,
1195 unsigned long *fdset)
1196 {
1197 unsigned long odd;
1198 nr = DIV_ROUND_UP(nr, __COMPAT_NFDBITS);
1199
1200 if (!ufdset)
1201 return 0;
1202
1203 odd = nr & 1UL;
1204 nr &= ~1UL;
1205 while (nr) {
1206 unsigned long h, l;
1207 l = *fdset++;
1208 h = l >> 32;
1209 if (__put_user(l, ufdset) || __put_user(h, ufdset+1))
1210 return -EFAULT;
1211 ufdset += 2;
1212 nr -= 2;
1213 }
1214 if (odd && __put_user(*fdset, ufdset))
1215 return -EFAULT;
1216 return 0;
1217 }
1218
1219
1220 /*
1221 * This is a virtual copy of sys_select from fs/select.c and probably
1222 * should be compared to it from time to time
1223 */
1224
1225 /*
1226 * We can actually return ERESTARTSYS instead of EINTR, but I'd
1227 * like to be certain this leads to no problems. So I return
1228 * EINTR just for safety.
1229 *
1230 * Update: ERESTARTSYS breaks at least the xview clock binary, so
1231 * I'm trying ERESTARTNOHAND which restart only when you want to.
1232 */
1233 static int compat_core_sys_select(int n, compat_ulong_t __user *inp,
1234 compat_ulong_t __user *outp, compat_ulong_t __user *exp,
1235 struct timespec *end_time)
1236 {
1237 fd_set_bits fds;
1238 void *bits;
1239 int size, max_fds, ret = -EINVAL;
1240 struct fdtable *fdt;
1241 long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
1242
1243 if (n < 0)
1244 goto out_nofds;
1245
1246 /* max_fds can increase, so grab it once to avoid race */
1247 rcu_read_lock();
1248 fdt = files_fdtable(current->files);
1249 max_fds = fdt->max_fds;
1250 rcu_read_unlock();
1251 if (n > max_fds)
1252 n = max_fds;
1253
1254 /*
1255 * We need 6 bitmaps (in/out/ex for both incoming and outgoing),
1256 * since we used fdset we need to allocate memory in units of
1257 * long-words.
1258 */
1259 size = FDS_BYTES(n);
1260 bits = stack_fds;
1261 if (size > sizeof(stack_fds) / 6) {
1262 bits = kmalloc(6 * size, GFP_KERNEL);
1263 ret = -ENOMEM;
1264 if (!bits)
1265 goto out_nofds;
1266 }
1267 fds.in = (unsigned long *) bits;
1268 fds.out = (unsigned long *) (bits + size);
1269 fds.ex = (unsigned long *) (bits + 2*size);
1270 fds.res_in = (unsigned long *) (bits + 3*size);
1271 fds.res_out = (unsigned long *) (bits + 4*size);
1272 fds.res_ex = (unsigned long *) (bits + 5*size);
1273
1274 if ((ret = compat_get_fd_set(n, inp, fds.in)) ||
1275 (ret = compat_get_fd_set(n, outp, fds.out)) ||
1276 (ret = compat_get_fd_set(n, exp, fds.ex)))
1277 goto out;
1278 zero_fd_set(n, fds.res_in);
1279 zero_fd_set(n, fds.res_out);
1280 zero_fd_set(n, fds.res_ex);
1281
1282 ret = do_select(n, &fds, end_time);
1283
1284 if (ret < 0)
1285 goto out;
1286 if (!ret) {
1287 ret = -ERESTARTNOHAND;
1288 if (signal_pending(current))
1289 goto out;
1290 ret = 0;
1291 }
1292
1293 if (compat_set_fd_set(n, inp, fds.res_in) ||
1294 compat_set_fd_set(n, outp, fds.res_out) ||
1295 compat_set_fd_set(n, exp, fds.res_ex))
1296 ret = -EFAULT;
1297 out:
1298 if (bits != stack_fds)
1299 kfree(bits);
1300 out_nofds:
1301 return ret;
1302 }
1303
1304 COMPAT_SYSCALL_DEFINE5(select, int, n, compat_ulong_t __user *, inp,
1305 compat_ulong_t __user *, outp, compat_ulong_t __user *, exp,
1306 struct compat_timeval __user *, tvp)
1307 {
1308 struct timespec end_time, *to = NULL;
1309 struct compat_timeval tv;
1310 int ret;
1311
1312 if (tvp) {
1313 if (copy_from_user(&tv, tvp, sizeof(tv)))
1314 return -EFAULT;
1315
1316 to = &end_time;
1317 if (poll_select_set_timeout(to,
1318 tv.tv_sec + (tv.tv_usec / USEC_PER_SEC),
1319 (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC))
1320 return -EINVAL;
1321 }
1322
1323 ret = compat_core_sys_select(n, inp, outp, exp, to);
1324 ret = compat_poll_select_copy_remaining(&end_time, tvp, 1, ret);
1325
1326 return ret;
1327 }
1328
1329 struct compat_sel_arg_struct {
1330 compat_ulong_t n;
1331 compat_uptr_t inp;
1332 compat_uptr_t outp;
1333 compat_uptr_t exp;
1334 compat_uptr_t tvp;
1335 };
1336
1337 COMPAT_SYSCALL_DEFINE1(old_select, struct compat_sel_arg_struct __user *, arg)
1338 {
1339 struct compat_sel_arg_struct a;
1340
1341 if (copy_from_user(&a, arg, sizeof(a)))
1342 return -EFAULT;
1343 return compat_sys_select(a.n, compat_ptr(a.inp), compat_ptr(a.outp),
1344 compat_ptr(a.exp), compat_ptr(a.tvp));
1345 }
1346
1347 static long do_compat_pselect(int n, compat_ulong_t __user *inp,
1348 compat_ulong_t __user *outp, compat_ulong_t __user *exp,
1349 struct compat_timespec __user *tsp, compat_sigset_t __user *sigmask,
1350 compat_size_t sigsetsize)
1351 {
1352 compat_sigset_t ss32;
1353 sigset_t ksigmask, sigsaved;
1354 struct compat_timespec ts;
1355 struct timespec end_time, *to = NULL;
1356 int ret;
1357
1358 if (tsp) {
1359 if (copy_from_user(&ts, tsp, sizeof(ts)))
1360 return -EFAULT;
1361
1362 to = &end_time;
1363 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
1364 return -EINVAL;
1365 }
1366
1367 if (sigmask) {
1368 if (sigsetsize != sizeof(compat_sigset_t))
1369 return -EINVAL;
1370 if (copy_from_user(&ss32, sigmask, sizeof(ss32)))
1371 return -EFAULT;
1372 sigset_from_compat(&ksigmask, &ss32);
1373
1374 sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
1375 sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
1376 }
1377
1378 ret = compat_core_sys_select(n, inp, outp, exp, to);
1379 ret = compat_poll_select_copy_remaining(&end_time, tsp, 0, ret);
1380
1381 if (ret == -ERESTARTNOHAND) {
1382 /*
1383 * Don't restore the signal mask yet. Let do_signal() deliver
1384 * the signal on the way back to userspace, before the signal
1385 * mask is restored.
1386 */
1387 if (sigmask) {
1388 memcpy(&current->saved_sigmask, &sigsaved,
1389 sizeof(sigsaved));
1390 set_restore_sigmask();
1391 }
1392 } else if (sigmask)
1393 sigprocmask(SIG_SETMASK, &sigsaved, NULL);
1394
1395 return ret;
1396 }
1397
1398 COMPAT_SYSCALL_DEFINE6(pselect6, int, n, compat_ulong_t __user *, inp,
1399 compat_ulong_t __user *, outp, compat_ulong_t __user *, exp,
1400 struct compat_timespec __user *, tsp, void __user *, sig)
1401 {
1402 compat_size_t sigsetsize = 0;
1403 compat_uptr_t up = 0;
1404
1405 if (sig) {
1406 if (!access_ok(VERIFY_READ, sig,
1407 sizeof(compat_uptr_t)+sizeof(compat_size_t)) ||
1408 __get_user(up, (compat_uptr_t __user *)sig) ||
1409 __get_user(sigsetsize,
1410 (compat_size_t __user *)(sig+sizeof(up))))
1411 return -EFAULT;
1412 }
1413 return do_compat_pselect(n, inp, outp, exp, tsp, compat_ptr(up),
1414 sigsetsize);
1415 }
1416
1417 COMPAT_SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds,
1418 unsigned int, nfds, struct compat_timespec __user *, tsp,
1419 const compat_sigset_t __user *, sigmask, compat_size_t, sigsetsize)
1420 {
1421 compat_sigset_t ss32;
1422 sigset_t ksigmask, sigsaved;
1423 struct compat_timespec ts;
1424 struct timespec end_time, *to = NULL;
1425 int ret;
1426
1427 if (tsp) {
1428 if (copy_from_user(&ts, tsp, sizeof(ts)))
1429 return -EFAULT;
1430
1431 to = &end_time;
1432 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
1433 return -EINVAL;
1434 }
1435
1436 if (sigmask) {
1437 if (sigsetsize != sizeof(compat_sigset_t))
1438 return -EINVAL;
1439 if (copy_from_user(&ss32, sigmask, sizeof(ss32)))
1440 return -EFAULT;
1441 sigset_from_compat(&ksigmask, &ss32);
1442
1443 sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
1444 sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
1445 }
1446
1447 ret = do_sys_poll(ufds, nfds, to);
1448
1449 /* We can restart this syscall, usually */
1450 if (ret == -EINTR) {
1451 /*
1452 * Don't restore the signal mask yet. Let do_signal() deliver
1453 * the signal on the way back to userspace, before the signal
1454 * mask is restored.
1455 */
1456 if (sigmask) {
1457 memcpy(&current->saved_sigmask, &sigsaved,
1458 sizeof(sigsaved));
1459 set_restore_sigmask();
1460 }
1461 ret = -ERESTARTNOHAND;
1462 } else if (sigmask)
1463 sigprocmask(SIG_SETMASK, &sigsaved, NULL);
1464
1465 ret = compat_poll_select_copy_remaining(&end_time, tsp, 0, ret);
1466
1467 return ret;
1468 }
1469 #endif
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