projects/linux·blob v2.6.21 · refs

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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/syscalls.h>
18#include <linux/module.h>
19#include <linux/slab.h>
20#include <linux/smp_lock.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#define ROUND_UP(x,y) (((x)+(y)-1)/(y))
30#define DEFAULT_POLLMASK (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)
31
32struct poll_table_page {
33 struct poll_table_page * next;
34 struct poll_table_entry * entry;
35 struct poll_table_entry entries[0];
36};
37
38#define POLL_TABLE_FULL(table) \
39 ((unsigned long)((table)->entry+1) > PAGE_SIZE + (unsigned long)(table))
40
41/*
42 * Ok, Peter made a complicated, but straightforward multiple_wait() function.
43 * I have rewritten this, taking some shortcuts: This code may not be easy to
44 * follow, but it should be free of race-conditions, and it's practical. If you
45 * understand what I'm doing here, then you understand how the linux
46 * sleep/wakeup mechanism works.
47 *
48 * Two very simple procedures, poll_wait() and poll_freewait() make all the
49 * work. poll_wait() is an inline-function defined in <linux/poll.h>,
50 * as all select/poll functions have to call it to add an entry to the
51 * poll table.
52 */
53static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
54 poll_table *p);
55
56void poll_initwait(struct poll_wqueues *pwq)
57{
58 init_poll_funcptr(&pwq->pt, __pollwait);
59 pwq->error = 0;
60 pwq->table = NULL;
61 pwq->inline_index = 0;
62}
63
64EXPORT_SYMBOL(poll_initwait);
65
66static void free_poll_entry(struct poll_table_entry *entry)
67{
68 remove_wait_queue(entry->wait_address,&entry->wait);
69 fput(entry->filp);
70}
71
72void poll_freewait(struct poll_wqueues *pwq)
73{
74 struct poll_table_page * p = pwq->table;
75 int i;
76 for (i = 0; i < pwq->inline_index; i++)
77 free_poll_entry(pwq->inline_entries + i);
78 while (p) {
79 struct poll_table_entry * entry;
80 struct poll_table_page *old;
81
82 entry = p->entry;
83 do {
84 entry--;
85 free_poll_entry(entry);
86 } while (entry > p->entries);
87 old = p;
88 p = p->next;
89 free_page((unsigned long) old);
90 }
91}
92
93EXPORT_SYMBOL(poll_freewait);
94
95static struct poll_table_entry *poll_get_entry(poll_table *_p)
96{
97 struct poll_wqueues *p = container_of(_p, struct poll_wqueues, pt);
98 struct poll_table_page *table = p->table;
99
100 if (p->inline_index < N_INLINE_POLL_ENTRIES)
101 return p->inline_entries + p->inline_index++;
102
103 if (!table || POLL_TABLE_FULL(table)) {
104 struct poll_table_page *new_table;
105
106 new_table = (struct poll_table_page *) __get_free_page(GFP_KERNEL);
107 if (!new_table) {
108 p->error = -ENOMEM;
109 __set_current_state(TASK_RUNNING);
110 return NULL;
111 }
112 new_table->entry = new_table->entries;
113 new_table->next = table;
114 p->table = new_table;
115 table = new_table;
116 }
117
118 return table->entry++;
119}
120
121/* Add a new entry */
122static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
123 poll_table *p)
124{
125 struct poll_table_entry *entry = poll_get_entry(p);
126 if (!entry)
127 return;
128 get_file(filp);
129 entry->filp = filp;
130 entry->wait_address = wait_address;
131 init_waitqueue_entry(&entry->wait, current);
132 add_wait_queue(wait_address,&entry->wait);
133}
134
135#define FDS_IN(fds, n) (fds->in + n)
136#define FDS_OUT(fds, n) (fds->out + n)
137#define FDS_EX(fds, n) (fds->ex + n)
138
139#define BITS(fds, n) (*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n))
140
141static int max_select_fd(unsigned long n, fd_set_bits *fds)
142{
143 unsigned long *open_fds;
144 unsigned long set;
145 int max;
146 struct fdtable *fdt;
147
148 /* handle last in-complete long-word first */
149 set = ~(~0UL << (n & (__NFDBITS-1)));
150 n /= __NFDBITS;
151 fdt = files_fdtable(current->files);
152 open_fds = fdt->open_fds->fds_bits+n;
153 max = 0;
154 if (set) {
155 set &= BITS(fds, n);
156 if (set) {
157 if (!(set & ~*open_fds))
158 goto get_max;
159 return -EBADF;
160 }
161 }
162 while (n) {
163 open_fds--;
164 n--;
165 set = BITS(fds, n);
166 if (!set)
167 continue;
168 if (set & ~*open_fds)
169 return -EBADF;
170 if (max)
171 continue;
172get_max:
173 do {
174 max++;
175 set >>= 1;
176 } while (set);
177 max += n * __NFDBITS;
178 }
179
180 return max;
181}
182
183#define BIT(i) (1UL << ((i)&(__NFDBITS-1)))
184#define MEM(i,m) ((m)+(unsigned)(i)/__NFDBITS)
185#define ISSET(i,m) (((i)&*(m)) != 0)
186#define SET(i,m) (*(m) |= (i))
187
188#define POLLIN_SET (POLLRDNORM | POLLRDBAND | POLLIN | POLLHUP | POLLERR)
189#define POLLOUT_SET (POLLWRBAND | POLLWRNORM | POLLOUT | POLLERR)
190#define POLLEX_SET (POLLPRI)
191
192int do_select(int n, fd_set_bits *fds, s64 *timeout)
193{
194 struct poll_wqueues table;
195 poll_table *wait;
196 int retval, i;
197
198 rcu_read_lock();
199 retval = max_select_fd(n, fds);
200 rcu_read_unlock();
201
202 if (retval < 0)
203 return retval;
204 n = retval;
205
206 poll_initwait(&table);
207 wait = &table.pt;
208 if (!*timeout)
209 wait = NULL;
210 retval = 0;
211 for (;;) {
212 unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp;
213 long __timeout;
214
215 set_current_state(TASK_INTERRUPTIBLE);
216
217 inp = fds->in; outp = fds->out; exp = fds->ex;
218 rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex;
219
220 for (i = 0; i < n; ++rinp, ++routp, ++rexp) {
221 unsigned long in, out, ex, all_bits, bit = 1, mask, j;
222 unsigned long res_in = 0, res_out = 0, res_ex = 0;
223 const struct file_operations *f_op = NULL;
224 struct file *file = NULL;
225
226 in = *inp++; out = *outp++; ex = *exp++;
227 all_bits = in | out | ex;
228 if (all_bits == 0) {
229 i += __NFDBITS;
230 continue;
231 }
232
233 for (j = 0; j < __NFDBITS; ++j, ++i, bit <<= 1) {
234 int fput_needed;
235 if (i >= n)
236 break;
237 if (!(bit & all_bits))
238 continue;
239 file = fget_light(i, &fput_needed);
240 if (file) {
241 f_op = file->f_op;
242 mask = DEFAULT_POLLMASK;
243 if (f_op && f_op->poll)
244 mask = (*f_op->poll)(file, retval ? NULL : wait);
245 fput_light(file, fput_needed);
246 if ((mask & POLLIN_SET) && (in & bit)) {
247 res_in |= bit;
248 retval++;
249 }
250 if ((mask & POLLOUT_SET) && (out & bit)) {
251 res_out |= bit;
252 retval++;
253 }
254 if ((mask & POLLEX_SET) && (ex & bit)) {
255 res_ex |= bit;
256 retval++;
257 }
258 }
259 cond_resched();
260 }
261 if (res_in)
262 *rinp = res_in;
263 if (res_out)
264 *routp = res_out;
265 if (res_ex)
266 *rexp = res_ex;
267 }
268 wait = NULL;
269 if (retval || !*timeout || signal_pending(current))
270 break;
271 if(table.error) {
272 retval = table.error;
273 break;
274 }
275
276 if (*timeout < 0) {
277 /* Wait indefinitely */
278 __timeout = MAX_SCHEDULE_TIMEOUT;
279 } else if (unlikely(*timeout >= (s64)MAX_SCHEDULE_TIMEOUT - 1)) {
280 /* Wait for longer than MAX_SCHEDULE_TIMEOUT. Do it in a loop */
281 __timeout = MAX_SCHEDULE_TIMEOUT - 1;
282 *timeout -= __timeout;
283 } else {
284 __timeout = *timeout;
285 *timeout = 0;
286 }
287 __timeout = schedule_timeout(__timeout);
288 if (*timeout >= 0)
289 *timeout += __timeout;
290 }
291 __set_current_state(TASK_RUNNING);
292
293 poll_freewait(&table);
294
295 return retval;
296}
297
298/*
299 * We can actually return ERESTARTSYS instead of EINTR, but I'd
300 * like to be certain this leads to no problems. So I return
301 * EINTR just for safety.
302 *
303 * Update: ERESTARTSYS breaks at least the xview clock binary, so
304 * I'm trying ERESTARTNOHAND which restart only when you want to.
305 */
306#define MAX_SELECT_SECONDS \
307 ((unsigned long) (MAX_SCHEDULE_TIMEOUT / HZ)-1)
308
309static int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
310 fd_set __user *exp, s64 *timeout)
311{
312 fd_set_bits fds;
313 void *bits;
314 int ret, max_fds;
315 unsigned int size;
316 struct fdtable *fdt;
317 /* Allocate small arguments on the stack to save memory and be faster */
318 long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
319
320 ret = -EINVAL;
321 if (n < 0)
322 goto out_nofds;
323
324 /* max_fds can increase, so grab it once to avoid race */
325 rcu_read_lock();
326 fdt = files_fdtable(current->files);
327 max_fds = fdt->max_fds;
328 rcu_read_unlock();
329 if (n > max_fds)
330 n = max_fds;
331
332 /*
333 * We need 6 bitmaps (in/out/ex for both incoming and outgoing),
334 * since we used fdset we need to allocate memory in units of
335 * long-words.
336 */
337 size = FDS_BYTES(n);
338 bits = stack_fds;
339 if (size > sizeof(stack_fds) / 6) {
340 /* Not enough space in on-stack array; must use kmalloc */
341 ret = -ENOMEM;
342 bits = kmalloc(6 * size, GFP_KERNEL);
343 if (!bits)
344 goto out_nofds;
345 }
346 fds.in = bits;
347 fds.out = bits + size;
348 fds.ex = bits + 2*size;
349 fds.res_in = bits + 3*size;
350 fds.res_out = bits + 4*size;
351 fds.res_ex = bits + 5*size;
352
353 if ((ret = get_fd_set(n, inp, fds.in)) ||
354 (ret = get_fd_set(n, outp, fds.out)) ||
355 (ret = get_fd_set(n, exp, fds.ex)))
356 goto out;
357 zero_fd_set(n, fds.res_in);
358 zero_fd_set(n, fds.res_out);
359 zero_fd_set(n, fds.res_ex);
360
361 ret = do_select(n, &fds, timeout);
362
363 if (ret < 0)
364 goto out;
365 if (!ret) {
366 ret = -ERESTARTNOHAND;
367 if (signal_pending(current))
368 goto out;
369 ret = 0;
370 }
371
372 if (set_fd_set(n, inp, fds.res_in) ||
373 set_fd_set(n, outp, fds.res_out) ||
374 set_fd_set(n, exp, fds.res_ex))
375 ret = -EFAULT;
376
377out:
378 if (bits != stack_fds)
379 kfree(bits);
380out_nofds:
381 return ret;
382}
383
384asmlinkage long sys_select(int n, fd_set __user *inp, fd_set __user *outp,
385 fd_set __user *exp, struct timeval __user *tvp)
386{
387 s64 timeout = -1;
388 struct timeval tv;
389 int ret;
390
391 if (tvp) {
392 if (copy_from_user(&tv, tvp, sizeof(tv)))
393 return -EFAULT;
394
395 if (tv.tv_sec < 0 || tv.tv_usec < 0)
396 return -EINVAL;
397
398 /* Cast to u64 to make GCC stop complaining */
399 if ((u64)tv.tv_sec >= (u64)MAX_INT64_SECONDS)
400 timeout = -1; /* infinite */
401 else {
402 timeout = ROUND_UP(tv.tv_usec, USEC_PER_SEC/HZ);
403 timeout += tv.tv_sec * HZ;
404 }
405 }
406
407 ret = core_sys_select(n, inp, outp, exp, &timeout);
408
409 if (tvp) {
410 struct timeval rtv;
411
412 if (current->personality & STICKY_TIMEOUTS)
413 goto sticky;
414 rtv.tv_usec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ));
415 rtv.tv_sec = timeout;
416 if (timeval_compare(&rtv, &tv) >= 0)
417 rtv = tv;
418 if (copy_to_user(tvp, &rtv, sizeof(rtv))) {
419sticky:
420 /*
421 * If an application puts its timeval in read-only
422 * memory, we don't want the Linux-specific update to
423 * the timeval to cause a fault after the select has
424 * completed successfully. However, because we're not
425 * updating the timeval, we can't restart the system
426 * call.
427 */
428 if (ret == -ERESTARTNOHAND)
429 ret = -EINTR;
430 }
431 }
432
433 return ret;
434}
435
436#ifdef TIF_RESTORE_SIGMASK
437asmlinkage long sys_pselect7(int n, fd_set __user *inp, fd_set __user *outp,
438 fd_set __user *exp, struct timespec __user *tsp,
439 const sigset_t __user *sigmask, size_t sigsetsize)
440{
441 s64 timeout = MAX_SCHEDULE_TIMEOUT;
442 sigset_t ksigmask, sigsaved;
443 struct timespec ts;
444 int ret;
445
446 if (tsp) {
447 if (copy_from_user(&ts, tsp, sizeof(ts)))
448 return -EFAULT;
449
450 if (ts.tv_sec < 0 || ts.tv_nsec < 0)
451 return -EINVAL;
452
453 /* Cast to u64 to make GCC stop complaining */
454 if ((u64)ts.tv_sec >= (u64)MAX_INT64_SECONDS)
455 timeout = -1; /* infinite */
456 else {
457 timeout = ROUND_UP(ts.tv_nsec, NSEC_PER_SEC/HZ);
458 timeout += ts.tv_sec * HZ;
459 }
460 }
461
462 if (sigmask) {
463 /* XXX: Don't preclude handling different sized sigset_t's. */
464 if (sigsetsize != sizeof(sigset_t))
465 return -EINVAL;
466 if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask)))
467 return -EFAULT;
468
469 sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
470 sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
471 }
472
473 ret = core_sys_select(n, inp, outp, exp, &timeout);
474
475 if (tsp) {
476 struct timespec rts;
477
478 if (current->personality & STICKY_TIMEOUTS)
479 goto sticky;
480 rts.tv_nsec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)) *
481 1000;
482 rts.tv_sec = timeout;
483 if (timespec_compare(&rts, &ts) >= 0)
484 rts = ts;
485 if (copy_to_user(tsp, &rts, sizeof(rts))) {
486sticky:
487 /*
488 * If an application puts its timeval in read-only
489 * memory, we don't want the Linux-specific update to
490 * the timeval to cause a fault after the select has
491 * completed successfully. However, because we're not
492 * updating the timeval, we can't restart the system
493 * call.
494 */
495 if (ret == -ERESTARTNOHAND)
496 ret = -EINTR;
497 }
498 }
499
500 if (ret == -ERESTARTNOHAND) {
501 /*
502 * Don't restore the signal mask yet. Let do_signal() deliver
503 * the signal on the way back to userspace, before the signal
504 * mask is restored.
505 */
506 if (sigmask) {
507 memcpy(&current->saved_sigmask, &sigsaved,
508 sizeof(sigsaved));
509 set_thread_flag(TIF_RESTORE_SIGMASK);
510 }
511 } else if (sigmask)
512 sigprocmask(SIG_SETMASK, &sigsaved, NULL);
513
514 return ret;
515}
516
517/*
518 * Most architectures can't handle 7-argument syscalls. So we provide a
519 * 6-argument version where the sixth argument is a pointer to a structure
520 * which has a pointer to the sigset_t itself followed by a size_t containing
521 * the sigset size.
522 */
523asmlinkage long sys_pselect6(int n, fd_set __user *inp, fd_set __user *outp,
524 fd_set __user *exp, struct timespec __user *tsp, void __user *sig)
525{
526 size_t sigsetsize = 0;
527 sigset_t __user *up = NULL;
528
529 if (sig) {
530 if (!access_ok(VERIFY_READ, sig, sizeof(void *)+sizeof(size_t))
531 || __get_user(up, (sigset_t __user * __user *)sig)
532 || __get_user(sigsetsize,
533 (size_t __user *)(sig+sizeof(void *))))
534 return -EFAULT;
535 }
536
537 return sys_pselect7(n, inp, outp, exp, tsp, up, sigsetsize);
538}
539#endif /* TIF_RESTORE_SIGMASK */
540
541struct poll_list {
542 struct poll_list *next;
543 int len;
544 struct pollfd entries[0];
545};
546
547#define POLLFD_PER_PAGE ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd))
548
549/*
550 * Fish for pollable events on the pollfd->fd file descriptor. We're only
551 * interested in events matching the pollfd->events mask, and the result
552 * matching that mask is both recorded in pollfd->revents and returned. The
553 * pwait poll_table will be used by the fd-provided poll handler for waiting,
554 * if non-NULL.
555 */
556static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait)
557{
558 unsigned int mask;
559 int fd;
560
561 mask = 0;
562 fd = pollfd->fd;
563 if (fd >= 0) {
564 int fput_needed;
565 struct file * file;
566
567 file = fget_light(fd, &fput_needed);
568 mask = POLLNVAL;
569 if (file != NULL) {
570 mask = DEFAULT_POLLMASK;
571 if (file->f_op && file->f_op->poll)
572 mask = file->f_op->poll(file, pwait);
573 /* Mask out unneeded events. */
574 mask &= pollfd->events | POLLERR | POLLHUP;
575 fput_light(file, fput_needed);
576 }
577 }
578 pollfd->revents = mask;
579
580 return mask;
581}
582
583static int do_poll(unsigned int nfds, struct poll_list *list,
584 struct poll_wqueues *wait, s64 *timeout)
585{
586 int count = 0;
587 poll_table* pt = &wait->pt;
588
589 /* Optimise the no-wait case */
590 if (!(*timeout))
591 pt = NULL;
592
593 for (;;) {
594 struct poll_list *walk;
595 long __timeout;
596
597 set_current_state(TASK_INTERRUPTIBLE);
598 for (walk = list; walk != NULL; walk = walk->next) {
599 struct pollfd * pfd, * pfd_end;
600
601 pfd = walk->entries;
602 pfd_end = pfd + walk->len;
603 for (; pfd != pfd_end; pfd++) {
604 /*
605 * Fish for events. If we found one, record it
606 * and kill the poll_table, so we don't
607 * needlessly register any other waiters after
608 * this. They'll get immediately deregistered
609 * when we break out and return.
610 */
611 if (do_pollfd(pfd, pt)) {
612 count++;
613 pt = NULL;
614 }
615 }
616 }
617 /*
618 * All waiters have already been registered, so don't provide
619 * a poll_table to them on the next loop iteration.
620 */
621 pt = NULL;
622 if (count || !*timeout || signal_pending(current))
623 break;
624 count = wait->error;
625 if (count)
626 break;
627
628 if (*timeout < 0) {
629 /* Wait indefinitely */
630 __timeout = MAX_SCHEDULE_TIMEOUT;
631 } else if (unlikely(*timeout >= (s64)MAX_SCHEDULE_TIMEOUT-1)) {
632 /*
633 * Wait for longer than MAX_SCHEDULE_TIMEOUT. Do it in
634 * a loop
635 */
636 __timeout = MAX_SCHEDULE_TIMEOUT - 1;
637 *timeout -= __timeout;
638 } else {
639 __timeout = *timeout;
640 *timeout = 0;
641 }
642
643 __timeout = schedule_timeout(__timeout);
644 if (*timeout >= 0)
645 *timeout += __timeout;
646 }
647 __set_current_state(TASK_RUNNING);
648 return count;
649}
650
651#define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \
652 sizeof(struct pollfd))
653
654int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds, s64 *timeout)
655{
656 struct poll_wqueues table;
657 int fdcount, err;
658 unsigned int i;
659 struct poll_list *head;
660 struct poll_list *walk;
661 /* Allocate small arguments on the stack to save memory and be
662 faster - use long to make sure the buffer is aligned properly
663 on 64 bit archs to avoid unaligned access */
664 long stack_pps[POLL_STACK_ALLOC/sizeof(long)];
665 struct poll_list *stack_pp = NULL;
666
667 /* Do a sanity check on nfds ... */
668 if (nfds > current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
669 return -EINVAL;
670
671 poll_initwait(&table);
672
673 head = NULL;
674 walk = NULL;
675 i = nfds;
676 err = -ENOMEM;
677 while(i!=0) {
678 struct poll_list *pp;
679 int num, size;
680 if (stack_pp == NULL)
681 num = N_STACK_PPS;
682 else
683 num = POLLFD_PER_PAGE;
684 if (num > i)
685 num = i;
686 size = sizeof(struct poll_list) + sizeof(struct pollfd)*num;
687 if (!stack_pp)
688 stack_pp = pp = (struct poll_list *)stack_pps;
689 else {
690 pp = kmalloc(size, GFP_KERNEL);
691 if (!pp)
692 goto out_fds;
693 }
694 pp->next=NULL;
695 pp->len = num;
696 if (head == NULL)
697 head = pp;
698 else
699 walk->next = pp;
700
701 walk = pp;
702 if (copy_from_user(pp->entries, ufds + nfds-i,
703 sizeof(struct pollfd)*num)) {
704 err = -EFAULT;
705 goto out_fds;
706 }
707 i -= pp->len;
708 }
709
710 fdcount = do_poll(nfds, head, &table, timeout);
711
712 /* OK, now copy the revents fields back to user space. */
713 walk = head;
714 err = -EFAULT;
715 while(walk != NULL) {
716 struct pollfd *fds = walk->entries;
717 int j;
718
719 for (j=0; j < walk->len; j++, ufds++) {
720 if(__put_user(fds[j].revents, &ufds->revents))
721 goto out_fds;
722 }
723 walk = walk->next;
724 }
725 err = fdcount;
726 if (!fdcount && signal_pending(current))
727 err = -EINTR;
728out_fds:
729 walk = head;
730 while(walk!=NULL) {
731 struct poll_list *pp = walk->next;
732 if (walk != stack_pp)
733 kfree(walk);
734 walk = pp;
735 }
736 poll_freewait(&table);
737 return err;
738}
739
740asmlinkage long sys_poll(struct pollfd __user *ufds, unsigned int nfds,
741 long timeout_msecs)
742{
743 s64 timeout_jiffies;
744
745 if (timeout_msecs > 0) {
746#if HZ > 1000
747 /* We can only overflow if HZ > 1000 */
748 if (timeout_msecs / 1000 > (s64)0x7fffffffffffffffULL / (s64)HZ)
749 timeout_jiffies = -1;
750 else
751#endif
752 timeout_jiffies = msecs_to_jiffies(timeout_msecs);
753 } else {
754 /* Infinite (< 0) or no (0) timeout */
755 timeout_jiffies = timeout_msecs;
756 }
757
758 return do_sys_poll(ufds, nfds, &timeout_jiffies);
759}
760
761#ifdef TIF_RESTORE_SIGMASK
762asmlinkage long sys_ppoll(struct pollfd __user *ufds, unsigned int nfds,
763 struct timespec __user *tsp, const sigset_t __user *sigmask,
764 size_t sigsetsize)
765{
766 sigset_t ksigmask, sigsaved;
767 struct timespec ts;
768 s64 timeout = -1;
769 int ret;
770
771 if (tsp) {
772 if (copy_from_user(&ts, tsp, sizeof(ts)))
773 return -EFAULT;
774
775 /* Cast to u64 to make GCC stop complaining */
776 if ((u64)ts.tv_sec >= (u64)MAX_INT64_SECONDS)
777 timeout = -1; /* infinite */
778 else {
779 timeout = ROUND_UP(ts.tv_nsec, NSEC_PER_SEC/HZ);
780 timeout += ts.tv_sec * HZ;
781 }
782 }
783
784 if (sigmask) {
785 /* XXX: Don't preclude handling different sized sigset_t's. */
786 if (sigsetsize != sizeof(sigset_t))
787 return -EINVAL;
788 if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask)))
789 return -EFAULT;
790
791 sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
792 sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
793 }
794
795 ret = do_sys_poll(ufds, nfds, &timeout);
796
797 /* We can restart this syscall, usually */
798 if (ret == -EINTR) {
799 /*
800 * Don't restore the signal mask yet. Let do_signal() deliver
801 * the signal on the way back to userspace, before the signal
802 * mask is restored.
803 */
804 if (sigmask) {
805 memcpy(&current->saved_sigmask, &sigsaved,
806 sizeof(sigsaved));
807 set_thread_flag(TIF_RESTORE_SIGMASK);
808 }
809 ret = -ERESTARTNOHAND;
810 } else if (sigmask)
811 sigprocmask(SIG_SETMASK, &sigsaved, NULL);
812
813 if (tsp && timeout >= 0) {
814 struct timespec rts;
815
816 if (current->personality & STICKY_TIMEOUTS)
817 goto sticky;
818 /* Yes, we know it's actually an s64, but it's also positive. */
819 rts.tv_nsec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)) *
820 1000;
821 rts.tv_sec = timeout;
822 if (timespec_compare(&rts, &ts) >= 0)
823 rts = ts;
824 if (copy_to_user(tsp, &rts, sizeof(rts))) {
825 sticky:
826 /*
827 * If an application puts its timeval in read-only
828 * memory, we don't want the Linux-specific update to
829 * the timeval to cause a fault after the select has
830 * completed successfully. However, because we're not
831 * updating the timeval, we can't restart the system
832 * call.
833 */
834 if (ret == -ERESTARTNOHAND && timeout >= 0)
835 ret = -EINTR;
836 }
837 }
838
839 return ret;
840}
841#endif /* TIF_RESTORE_SIGMASK */