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/syscalls.h>
19 #include <linux/module.h>
20 #include <linux/slab.h>
21 #include <linux/poll.h>
22 #include <linux/personality.h> /* for STICKY_TIMEOUTS */
23 #include <linux/file.h>
24 #include <linux/fs.h>
25 #include <linux/rcupdate.h>
26
27 #include <asm/uaccess.h>
28
29 struct poll_table_page {
30 struct poll_table_page * next;
31 struct poll_table_entry * entry;
32 struct poll_table_entry entries[0];
33 };
34
35 #define POLL_TABLE_FULL(table) \
36 ((unsigned long)((table)->entry+1) > PAGE_SIZE + (unsigned long)(table))
37
38 /*
39 * Ok, Peter made a complicated, but straightforward multiple_wait() function.
40 * I have rewritten this, taking some shortcuts: This code may not be easy to
41 * follow, but it should be free of race-conditions, and it's practical. If you
42 * understand what I'm doing here, then you understand how the linux
43 * sleep/wakeup mechanism works.
44 *
45 * Two very simple procedures, poll_wait() and poll_freewait() make all the
46 * work. poll_wait() is an inline-function defined in <linux/poll.h>,
47 * as all select/poll functions have to call it to add an entry to the
48 * poll table.
49 */
50 static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
51 poll_table *p);
52
53 void poll_initwait(struct poll_wqueues *pwq)
54 {
55 init_poll_funcptr(&pwq->pt, __pollwait);
56 pwq->error = 0;
57 pwq->table = NULL;
58 pwq->inline_index = 0;
59 }
60
61 EXPORT_SYMBOL(poll_initwait);
62
63 static void free_poll_entry(struct poll_table_entry *entry)
64 {
65 remove_wait_queue(entry->wait_address, &entry->wait);
66 fput(entry->filp);
67 }
68
69 void poll_freewait(struct poll_wqueues *pwq)
70 {
71 struct poll_table_page * p = pwq->table;
72 int i;
73 for (i = 0; i < pwq->inline_index; i++)
74 free_poll_entry(pwq->inline_entries + i);
75 while (p) {
76 struct poll_table_entry * entry;
77 struct poll_table_page *old;
78
79 entry = p->entry;
80 do {
81 entry--;
82 free_poll_entry(entry);
83 } while (entry > p->entries);
84 old = p;
85 p = p->next;
86 free_page((unsigned long) old);
87 }
88 }
89
90 EXPORT_SYMBOL(poll_freewait);
91
92 static struct poll_table_entry *poll_get_entry(poll_table *_p)
93 {
94 struct poll_wqueues *p = container_of(_p, struct poll_wqueues, pt);
95 struct poll_table_page *table = p->table;
96
97 if (p->inline_index < N_INLINE_POLL_ENTRIES)
98 return p->inline_entries + p->inline_index++;
99
100 if (!table || POLL_TABLE_FULL(table)) {
101 struct poll_table_page *new_table;
102
103 new_table = (struct poll_table_page *) __get_free_page(GFP_KERNEL);
104 if (!new_table) {
105 p->error = -ENOMEM;
106 __set_current_state(TASK_RUNNING);
107 return NULL;
108 }
109 new_table->entry = new_table->entries;
110 new_table->next = table;
111 p->table = new_table;
112 table = new_table;
113 }
114
115 return table->entry++;
116 }
117
118 /* Add a new entry */
119 static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
120 poll_table *p)
121 {
122 struct poll_table_entry *entry = poll_get_entry(p);
123 if (!entry)
124 return;
125 get_file(filp);
126 entry->filp = filp;
127 entry->wait_address = wait_address;
128 init_waitqueue_entry(&entry->wait, current);
129 add_wait_queue(wait_address, &entry->wait);
130 }
131
132 #define FDS_IN(fds, n) (fds->in + n)
133 #define FDS_OUT(fds, n) (fds->out + n)
134 #define FDS_EX(fds, n) (fds->ex + n)
135
136 #define BITS(fds, n) (*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n))
137
138 static int max_select_fd(unsigned long n, fd_set_bits *fds)
139 {
140 unsigned long *open_fds;
141 unsigned long set;
142 int max;
143 struct fdtable *fdt;
144
145 /* handle last in-complete long-word first */
146 set = ~(~0UL << (n & (__NFDBITS-1)));
147 n /= __NFDBITS;
148 fdt = files_fdtable(current->files);
149 open_fds = fdt->open_fds->fds_bits+n;
150 max = 0;
151 if (set) {
152 set &= BITS(fds, n);
153 if (set) {
154 if (!(set & ~*open_fds))
155 goto get_max;
156 return -EBADF;
157 }
158 }
159 while (n) {
160 open_fds--;
161 n--;
162 set = BITS(fds, n);
163 if (!set)
164 continue;
165 if (set & ~*open_fds)
166 return -EBADF;
167 if (max)
168 continue;
169 get_max:
170 do {
171 max++;
172 set >>= 1;
173 } while (set);
174 max += n * __NFDBITS;
175 }
176
177 return max;
178 }
179
180 #define POLLIN_SET (POLLRDNORM | POLLRDBAND | POLLIN | POLLHUP | POLLERR)
181 #define POLLOUT_SET (POLLWRBAND | POLLWRNORM | POLLOUT | POLLERR)
182 #define POLLEX_SET (POLLPRI)
183
184 int do_select(int n, fd_set_bits *fds, s64 *timeout)
185 {
186 struct poll_wqueues table;
187 poll_table *wait;
188 int retval, i;
189
190 rcu_read_lock();
191 retval = max_select_fd(n, fds);
192 rcu_read_unlock();
193
194 if (retval < 0)
195 return retval;
196 n = retval;
197
198 poll_initwait(&table);
199 wait = &table.pt;
200 if (!*timeout)
201 wait = NULL;
202 retval = 0;
203 for (;;) {
204 unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp;
205 long __timeout;
206
207 set_current_state(TASK_INTERRUPTIBLE);
208
209 inp = fds->in; outp = fds->out; exp = fds->ex;
210 rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex;
211
212 for (i = 0; i < n; ++rinp, ++routp, ++rexp) {
213 unsigned long in, out, ex, all_bits, bit = 1, mask, j;
214 unsigned long res_in = 0, res_out = 0, res_ex = 0;
215 const struct file_operations *f_op = NULL;
216 struct file *file = NULL;
217
218 in = *inp++; out = *outp++; ex = *exp++;
219 all_bits = in | out | ex;
220 if (all_bits == 0) {
221 i += __NFDBITS;
222 continue;
223 }
224
225 for (j = 0; j < __NFDBITS; ++j, ++i, bit <<= 1) {
226 int fput_needed;
227 if (i >= n)
228 break;
229 if (!(bit & all_bits))
230 continue;
231 file = fget_light(i, &fput_needed);
232 if (file) {
233 f_op = file->f_op;
234 mask = DEFAULT_POLLMASK;
235 if (f_op && f_op->poll)
236 mask = (*f_op->poll)(file, retval ? NULL : wait);
237 fput_light(file, fput_needed);
238 if ((mask & POLLIN_SET) && (in & bit)) {
239 res_in |= bit;
240 retval++;
241 }
242 if ((mask & POLLOUT_SET) && (out & bit)) {
243 res_out |= bit;
244 retval++;
245 }
246 if ((mask & POLLEX_SET) && (ex & bit)) {
247 res_ex |= bit;
248 retval++;
249 }
250 }
251 cond_resched();
252 }
253 if (res_in)
254 *rinp = res_in;
255 if (res_out)
256 *routp = res_out;
257 if (res_ex)
258 *rexp = res_ex;
259 }
260 wait = NULL;
261 if (retval || !*timeout || signal_pending(current))
262 break;
263 if(table.error) {
264 retval = table.error;
265 break;
266 }
267
268 if (*timeout < 0) {
269 /* Wait indefinitely */
270 __timeout = MAX_SCHEDULE_TIMEOUT;
271 } else if (unlikely(*timeout >= (s64)MAX_SCHEDULE_TIMEOUT - 1)) {
272 /* Wait for longer than MAX_SCHEDULE_TIMEOUT. Do it in a loop */
273 __timeout = MAX_SCHEDULE_TIMEOUT - 1;
274 *timeout -= __timeout;
275 } else {
276 __timeout = *timeout;
277 *timeout = 0;
278 }
279 __timeout = schedule_timeout(__timeout);
280 if (*timeout >= 0)
281 *timeout += __timeout;
282 }
283 __set_current_state(TASK_RUNNING);
284
285 poll_freewait(&table);
286
287 return retval;
288 }
289
290 /*
291 * We can actually return ERESTARTSYS instead of EINTR, but I'd
292 * like to be certain this leads to no problems. So I return
293 * EINTR just for safety.
294 *
295 * Update: ERESTARTSYS breaks at least the xview clock binary, so
296 * I'm trying ERESTARTNOHAND which restart only when you want to.
297 */
298 #define MAX_SELECT_SECONDS \
299 ((unsigned long) (MAX_SCHEDULE_TIMEOUT / HZ)-1)
300
301 static int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
302 fd_set __user *exp, s64 *timeout)
303 {
304 fd_set_bits fds;
305 void *bits;
306 int ret, max_fds;
307 unsigned int size;
308 struct fdtable *fdt;
309 /* Allocate small arguments on the stack to save memory and be faster */
310 long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
311
312 ret = -EINVAL;
313 if (n < 0)
314 goto out_nofds;
315
316 /* max_fds can increase, so grab it once to avoid race */
317 rcu_read_lock();
318 fdt = files_fdtable(current->files);
319 max_fds = fdt->max_fds;
320 rcu_read_unlock();
321 if (n > max_fds)
322 n = max_fds;
323
324 /*
325 * We need 6 bitmaps (in/out/ex for both incoming and outgoing),
326 * since we used fdset we need to allocate memory in units of
327 * long-words.
328 */
329 size = FDS_BYTES(n);
330 bits = stack_fds;
331 if (size > sizeof(stack_fds) / 6) {
332 /* Not enough space in on-stack array; must use kmalloc */
333 ret = -ENOMEM;
334 bits = kmalloc(6 * size, GFP_KERNEL);
335 if (!bits)
336 goto out_nofds;
337 }
338 fds.in = bits;
339 fds.out = bits + size;
340 fds.ex = bits + 2*size;
341 fds.res_in = bits + 3*size;
342 fds.res_out = bits + 4*size;
343 fds.res_ex = bits + 5*size;
344
345 if ((ret = get_fd_set(n, inp, fds.in)) ||
346 (ret = get_fd_set(n, outp, fds.out)) ||
347 (ret = get_fd_set(n, exp, fds.ex)))
348 goto out;
349 zero_fd_set(n, fds.res_in);
350 zero_fd_set(n, fds.res_out);
351 zero_fd_set(n, fds.res_ex);
352
353 ret = do_select(n, &fds, timeout);
354
355 if (ret < 0)
356 goto out;
357 if (!ret) {
358 ret = -ERESTARTNOHAND;
359 if (signal_pending(current))
360 goto out;
361 ret = 0;
362 }
363
364 if (set_fd_set(n, inp, fds.res_in) ||
365 set_fd_set(n, outp, fds.res_out) ||
366 set_fd_set(n, exp, fds.res_ex))
367 ret = -EFAULT;
368
369 out:
370 if (bits != stack_fds)
371 kfree(bits);
372 out_nofds:
373 return ret;
374 }
375
376 asmlinkage long sys_select(int n, fd_set __user *inp, fd_set __user *outp,
377 fd_set __user *exp, struct timeval __user *tvp)
378 {
379 s64 timeout = -1;
380 struct timeval tv;
381 int ret;
382
383 if (tvp) {
384 if (copy_from_user(&tv, tvp, sizeof(tv)))
385 return -EFAULT;
386
387 if (tv.tv_sec < 0 || tv.tv_usec < 0)
388 return -EINVAL;
389
390 /* Cast to u64 to make GCC stop complaining */
391 if ((u64)tv.tv_sec >= (u64)MAX_INT64_SECONDS)
392 timeout = -1; /* infinite */
393 else {
394 timeout = DIV_ROUND_UP(tv.tv_usec, USEC_PER_SEC/HZ);
395 timeout += tv.tv_sec * HZ;
396 }
397 }
398
399 ret = core_sys_select(n, inp, outp, exp, &timeout);
400
401 if (tvp) {
402 struct timeval rtv;
403
404 if (current->personality & STICKY_TIMEOUTS)
405 goto sticky;
406 rtv.tv_usec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ));
407 rtv.tv_sec = timeout;
408 if (timeval_compare(&rtv, &tv) >= 0)
409 rtv = tv;
410 if (copy_to_user(tvp, &rtv, sizeof(rtv)))
411 return -EFAULT;
412 }
413 sticky:
414 if (ret == -ERESTARTNOHAND)
415 ret = -EINTR;
416
417 return ret;
418 }
419
420 #ifdef TIF_RESTORE_SIGMASK
421 asmlinkage long sys_pselect7(int n, fd_set __user *inp, fd_set __user *outp,
422 fd_set __user *exp, struct timespec __user *tsp,
423 const sigset_t __user *sigmask, size_t sigsetsize)
424 {
425 s64 timeout = MAX_SCHEDULE_TIMEOUT;
426 sigset_t ksigmask, sigsaved;
427 struct timespec ts;
428 int ret;
429
430 if (tsp) {
431 if (copy_from_user(&ts, tsp, sizeof(ts)))
432 return -EFAULT;
433
434 if (ts.tv_sec < 0 || ts.tv_nsec < 0)
435 return -EINVAL;
436
437 /* Cast to u64 to make GCC stop complaining */
438 if ((u64)ts.tv_sec >= (u64)MAX_INT64_SECONDS)
439 timeout = -1; /* infinite */
440 else {
441 timeout = DIV_ROUND_UP(ts.tv_nsec, NSEC_PER_SEC/HZ);
442 timeout += ts.tv_sec * HZ;
443 }
444 }
445
446 if (sigmask) {
447 /* XXX: Don't preclude handling different sized sigset_t's. */
448 if (sigsetsize != sizeof(sigset_t))
449 return -EINVAL;
450 if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask)))
451 return -EFAULT;
452
453 sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
454 sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
455 }
456
457 ret = core_sys_select(n, inp, outp, exp, &timeout);
458
459 if (tsp) {
460 struct timespec rts;
461
462 if (current->personality & STICKY_TIMEOUTS)
463 goto sticky;
464 rts.tv_nsec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)) *
465 1000;
466 rts.tv_sec = timeout;
467 if (timespec_compare(&rts, &ts) >= 0)
468 rts = ts;
469 if (copy_to_user(tsp, &rts, sizeof(rts))) {
470 sticky:
471 /*
472 * If an application puts its timeval in read-only
473 * memory, we don't want the Linux-specific update to
474 * the timeval to cause a fault after the select has
475 * completed successfully. However, because we're not
476 * updating the timeval, we can't restart the system
477 * call.
478 */
479 if (ret == -ERESTARTNOHAND)
480 ret = -EINTR;
481 }
482 }
483
484 if (ret == -ERESTARTNOHAND) {
485 /*
486 * Don't restore the signal mask yet. Let do_signal() deliver
487 * the signal on the way back to userspace, before the signal
488 * mask is restored.
489 */
490 if (sigmask) {
491 memcpy(¤t->saved_sigmask, &sigsaved,
492 sizeof(sigsaved));
493 set_thread_flag(TIF_RESTORE_SIGMASK);
494 }
495 } else if (sigmask)
496 sigprocmask(SIG_SETMASK, &sigsaved, NULL);
497
498 return ret;
499 }
500
501 /*
502 * Most architectures can't handle 7-argument syscalls. So we provide a
503 * 6-argument version where the sixth argument is a pointer to a structure
504 * which has a pointer to the sigset_t itself followed by a size_t containing
505 * the sigset size.
506 */
507 asmlinkage long sys_pselect6(int n, fd_set __user *inp, fd_set __user *outp,
508 fd_set __user *exp, struct timespec __user *tsp, void __user *sig)
509 {
510 size_t sigsetsize = 0;
511 sigset_t __user *up = NULL;
512
513 if (sig) {
514 if (!access_ok(VERIFY_READ, sig, sizeof(void *)+sizeof(size_t))
515 || __get_user(up, (sigset_t __user * __user *)sig)
516 || __get_user(sigsetsize,
517 (size_t __user *)(sig+sizeof(void *))))
518 return -EFAULT;
519 }
520
521 return sys_pselect7(n, inp, outp, exp, tsp, up, sigsetsize);
522 }
523 #endif /* TIF_RESTORE_SIGMASK */
524
525 struct poll_list {
526 struct poll_list *next;
527 int len;
528 struct pollfd entries[0];
529 };
530
531 #define POLLFD_PER_PAGE ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd))
532
533 /*
534 * Fish for pollable events on the pollfd->fd file descriptor. We're only
535 * interested in events matching the pollfd->events mask, and the result
536 * matching that mask is both recorded in pollfd->revents and returned. The
537 * pwait poll_table will be used by the fd-provided poll handler for waiting,
538 * if non-NULL.
539 */
540 static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait)
541 {
542 unsigned int mask;
543 int fd;
544
545 mask = 0;
546 fd = pollfd->fd;
547 if (fd >= 0) {
548 int fput_needed;
549 struct file * file;
550
551 file = fget_light(fd, &fput_needed);
552 mask = POLLNVAL;
553 if (file != NULL) {
554 mask = DEFAULT_POLLMASK;
555 if (file->f_op && file->f_op->poll)
556 mask = file->f_op->poll(file, pwait);
557 /* Mask out unneeded events. */
558 mask &= pollfd->events | POLLERR | POLLHUP;
559 fput_light(file, fput_needed);
560 }
561 }
562 pollfd->revents = mask;
563
564 return mask;
565 }
566
567 static int do_poll(unsigned int nfds, struct poll_list *list,
568 struct poll_wqueues *wait, s64 *timeout)
569 {
570 int count = 0;
571 poll_table* pt = &wait->pt;
572
573 /* Optimise the no-wait case */
574 if (!(*timeout))
575 pt = NULL;
576
577 for (;;) {
578 struct poll_list *walk;
579 long __timeout;
580
581 set_current_state(TASK_INTERRUPTIBLE);
582 for (walk = list; walk != NULL; walk = walk->next) {
583 struct pollfd * pfd, * pfd_end;
584
585 pfd = walk->entries;
586 pfd_end = pfd + walk->len;
587 for (; pfd != pfd_end; pfd++) {
588 /*
589 * Fish for events. If we found one, record it
590 * and kill the poll_table, so we don't
591 * needlessly register any other waiters after
592 * this. They'll get immediately deregistered
593 * when we break out and return.
594 */
595 if (do_pollfd(pfd, pt)) {
596 count++;
597 pt = NULL;
598 }
599 }
600 }
601 /*
602 * All waiters have already been registered, so don't provide
603 * a poll_table to them on the next loop iteration.
604 */
605 pt = NULL;
606 if (!count) {
607 count = wait->error;
608 if (signal_pending(current))
609 count = -EINTR;
610 }
611 if (count || !*timeout)
612 break;
613
614 if (*timeout < 0) {
615 /* Wait indefinitely */
616 __timeout = MAX_SCHEDULE_TIMEOUT;
617 } else if (unlikely(*timeout >= (s64)MAX_SCHEDULE_TIMEOUT-1)) {
618 /*
619 * Wait for longer than MAX_SCHEDULE_TIMEOUT. Do it in
620 * a loop
621 */
622 __timeout = MAX_SCHEDULE_TIMEOUT - 1;
623 *timeout -= __timeout;
624 } else {
625 __timeout = *timeout;
626 *timeout = 0;
627 }
628
629 __timeout = schedule_timeout(__timeout);
630 if (*timeout >= 0)
631 *timeout += __timeout;
632 }
633 __set_current_state(TASK_RUNNING);
634 return count;
635 }
636
637 #define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \
638 sizeof(struct pollfd))
639
640 int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds, s64 *timeout)
641 {
642 struct poll_wqueues table;
643 int err = -EFAULT, fdcount, len, size;
644 /* Allocate small arguments on the stack to save memory and be
645 faster - use long to make sure the buffer is aligned properly
646 on 64 bit archs to avoid unaligned access */
647 long stack_pps[POLL_STACK_ALLOC/sizeof(long)];
648 struct poll_list *const head = (struct poll_list *)stack_pps;
649 struct poll_list *walk = head;
650 unsigned long todo = nfds;
651
652 if (nfds > current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
653 return -EINVAL;
654
655 len = min_t(unsigned int, nfds, N_STACK_PPS);
656 for (;;) {
657 walk->next = NULL;
658 walk->len = len;
659 if (!len)
660 break;
661
662 if (copy_from_user(walk->entries, ufds + nfds-todo,
663 sizeof(struct pollfd) * walk->len))
664 goto out_fds;
665
666 todo -= walk->len;
667 if (!todo)
668 break;
669
670 len = min(todo, POLLFD_PER_PAGE);
671 size = sizeof(struct poll_list) + sizeof(struct pollfd) * len;
672 walk = walk->next = kmalloc(size, GFP_KERNEL);
673 if (!walk) {
674 err = -ENOMEM;
675 goto out_fds;
676 }
677 }
678
679 poll_initwait(&table);
680 fdcount = do_poll(nfds, head, &table, timeout);
681 poll_freewait(&table);
682
683 for (walk = head; walk; walk = walk->next) {
684 struct pollfd *fds = walk->entries;
685 int j;
686
687 for (j = 0; j < walk->len; j++, ufds++)
688 if (__put_user(fds[j].revents, &ufds->revents))
689 goto out_fds;
690 }
691
692 err = fdcount;
693 out_fds:
694 walk = head->next;
695 while (walk) {
696 struct poll_list *pos = walk;
697 walk = walk->next;
698 kfree(pos);
699 }
700
701 return err;
702 }
703
704 static long do_restart_poll(struct restart_block *restart_block)
705 {
706 struct pollfd __user *ufds = (struct pollfd __user*)restart_block->arg0;
707 int nfds = restart_block->arg1;
708 s64 timeout = ((s64)restart_block->arg3<<32) | (s64)restart_block->arg2;
709 int ret;
710
711 ret = do_sys_poll(ufds, nfds, &timeout);
712 if (ret == -EINTR) {
713 restart_block->fn = do_restart_poll;
714 restart_block->arg2 = timeout & 0xFFFFFFFF;
715 restart_block->arg3 = (u64)timeout >> 32;
716 ret = -ERESTART_RESTARTBLOCK;
717 }
718 return ret;
719 }
720
721 asmlinkage long sys_poll(struct pollfd __user *ufds, unsigned int nfds,
722 long timeout_msecs)
723 {
724 s64 timeout_jiffies;
725 int ret;
726
727 if (timeout_msecs > 0) {
728 #if HZ > 1000
729 /* We can only overflow if HZ > 1000 */
730 if (timeout_msecs / 1000 > (s64)0x7fffffffffffffffULL / (s64)HZ)
731 timeout_jiffies = -1;
732 else
733 #endif
734 timeout_jiffies = msecs_to_jiffies(timeout_msecs) + 1;
735 } else {
736 /* Infinite (< 0) or no (0) timeout */
737 timeout_jiffies = timeout_msecs;
738 }
739
740 ret = do_sys_poll(ufds, nfds, &timeout_jiffies);
741 if (ret == -EINTR) {
742 struct restart_block *restart_block;
743 restart_block = ¤t_thread_info()->restart_block;
744 restart_block->fn = do_restart_poll;
745 restart_block->arg0 = (unsigned long)ufds;
746 restart_block->arg1 = nfds;
747 restart_block->arg2 = timeout_jiffies & 0xFFFFFFFF;
748 restart_block->arg3 = (u64)timeout_jiffies >> 32;
749 ret = -ERESTART_RESTARTBLOCK;
750 }
751 return ret;
752 }
753
754 #ifdef TIF_RESTORE_SIGMASK
755 asmlinkage long sys_ppoll(struct pollfd __user *ufds, unsigned int nfds,
756 struct timespec __user *tsp, const sigset_t __user *sigmask,
757 size_t sigsetsize)
758 {
759 sigset_t ksigmask, sigsaved;
760 struct timespec ts;
761 s64 timeout = -1;
762 int ret;
763
764 if (tsp) {
765 if (copy_from_user(&ts, tsp, sizeof(ts)))
766 return -EFAULT;
767
768 /* Cast to u64 to make GCC stop complaining */
769 if ((u64)ts.tv_sec >= (u64)MAX_INT64_SECONDS)
770 timeout = -1; /* infinite */
771 else {
772 timeout = DIV_ROUND_UP(ts.tv_nsec, NSEC_PER_SEC/HZ);
773 timeout += ts.tv_sec * HZ;
774 }
775 }
776
777 if (sigmask) {
778 /* XXX: Don't preclude handling different sized sigset_t's. */
779 if (sigsetsize != sizeof(sigset_t))
780 return -EINVAL;
781 if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask)))
782 return -EFAULT;
783
784 sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
785 sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
786 }
787
788 ret = do_sys_poll(ufds, nfds, &timeout);
789
790 /* We can restart this syscall, usually */
791 if (ret == -EINTR) {
792 /*
793 * Don't restore the signal mask yet. Let do_signal() deliver
794 * the signal on the way back to userspace, before the signal
795 * mask is restored.
796 */
797 if (sigmask) {
798 memcpy(¤t->saved_sigmask, &sigsaved,
799 sizeof(sigsaved));
800 set_thread_flag(TIF_RESTORE_SIGMASK);
801 }
802 ret = -ERESTARTNOHAND;
803 } else if (sigmask)
804 sigprocmask(SIG_SETMASK, &sigsaved, NULL);
805
806 if (tsp && timeout >= 0) {
807 struct timespec rts;
808
809 if (current->personality & STICKY_TIMEOUTS)
810 goto sticky;
811 /* Yes, we know it's actually an s64, but it's also positive. */
812 rts.tv_nsec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)) *
813 1000;
814 rts.tv_sec = timeout;
815 if (timespec_compare(&rts, &ts) >= 0)
816 rts = ts;
817 if (copy_to_user(tsp, &rts, sizeof(rts))) {
818 sticky:
819 /*
820 * If an application puts its timeval in read-only
821 * memory, we don't want the Linux-specific update to
822 * the timeval to cause a fault after the select has
823 * completed successfully. However, because we're not
824 * updating the timeval, we can't restart the system
825 * call.
826 */
827 if (ret == -ERESTARTNOHAND && timeout >= 0)
828 ret = -EINTR;
829 }
830 }
831
832 return ret;
833 }
834 #endif /* TIF_RESTORE_SIGMASK */
835
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