blob: 500a669f779016eb33a4e570805285d6d44e7af2 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Milind Arun Choudhary022a1692007-05-08 00:29:02 -070017#include <linux/kernel.h>
Alexey Dobriyana99bbaf2009-10-04 16:11:37 +040018#include <linux/sched.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#include <linux/syscalls.h>
20#include <linux/module.h>
21#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#include <linux/poll.h>
23#include <linux/personality.h> /* for STICKY_TIMEOUTS */
24#include <linux/file.h>
Al Viro9f3acc32008-04-24 07:44:08 -040025#include <linux/fdtable.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#include <linux/fs.h>
Dipankar Sarmab8359962005-09-09 13:04:14 -070027#include <linux/rcupdate.h>
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -070028#include <linux/hrtimer.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070029
30#include <asm/uaccess.h>
31
Arjan van de Ven90d6e242008-09-01 15:55:35 -070032
33/*
34 * Estimate expected accuracy in ns from a timeval.
35 *
36 * After quite a bit of churning around, we've settled on
37 * a simple thing of taking 0.1% of the timeout as the
38 * slack, with a cap of 100 msec.
39 * "nice" tasks get a 0.5% slack instead.
40 *
41 * Consider this comment an open invitation to come up with even
42 * better solutions..
43 */
44
Guillaume Knispel5ae87e72009-09-22 16:43:30 -070045#define MAX_SLACK (100 * NSEC_PER_MSEC)
46
Arjan van de Ven96d2ab42008-09-07 16:08:55 -070047static long __estimate_accuracy(struct timespec *tv)
Arjan van de Ven90d6e242008-09-01 15:55:35 -070048{
Arjan van de Ven96d2ab42008-09-07 16:08:55 -070049 long slack;
Arjan van de Ven90d6e242008-09-01 15:55:35 -070050 int divfactor = 1000;
51
Guillaume Knispel5ae87e72009-09-22 16:43:30 -070052 if (tv->tv_sec < 0)
53 return 0;
54
Arjan van de Ven4ce105d2008-09-07 15:31:39 -070055 if (task_nice(current) > 0)
Arjan van de Ven90d6e242008-09-01 15:55:35 -070056 divfactor = divfactor / 5;
57
Guillaume Knispel5ae87e72009-09-22 16:43:30 -070058 if (tv->tv_sec > MAX_SLACK / (NSEC_PER_SEC/divfactor))
59 return MAX_SLACK;
60
Arjan van de Ven90d6e242008-09-01 15:55:35 -070061 slack = tv->tv_nsec / divfactor;
62 slack += tv->tv_sec * (NSEC_PER_SEC/divfactor);
63
Guillaume Knispel5ae87e72009-09-22 16:43:30 -070064 if (slack > MAX_SLACK)
65 return MAX_SLACK;
Arjan van de Ven96d2ab42008-09-07 16:08:55 -070066
Arjan van de Ven90d6e242008-09-01 15:55:35 -070067 return slack;
68}
69
Arjan van de Ven96d2ab42008-09-07 16:08:55 -070070static long estimate_accuracy(struct timespec *tv)
Arjan van de Ven90d6e242008-09-01 15:55:35 -070071{
72 unsigned long ret;
73 struct timespec now;
74
75 /*
76 * Realtime tasks get a slack of 0 for obvious reasons.
77 */
78
Arjan van de Ven4ce105d2008-09-07 15:31:39 -070079 if (rt_task(current))
Arjan van de Ven90d6e242008-09-01 15:55:35 -070080 return 0;
81
82 ktime_get_ts(&now);
83 now = timespec_sub(*tv, now);
84 ret = __estimate_accuracy(&now);
85 if (ret < current->timer_slack_ns)
86 return current->timer_slack_ns;
87 return ret;
88}
89
90
91
Linus Torvalds1da177e2005-04-16 15:20:36 -070092struct poll_table_page {
93 struct poll_table_page * next;
94 struct poll_table_entry * entry;
95 struct poll_table_entry entries[0];
96};
97
98#define POLL_TABLE_FULL(table) \
99 ((unsigned long)((table)->entry+1) > PAGE_SIZE + (unsigned long)(table))
100
101/*
102 * Ok, Peter made a complicated, but straightforward multiple_wait() function.
103 * I have rewritten this, taking some shortcuts: This code may not be easy to
104 * follow, but it should be free of race-conditions, and it's practical. If you
105 * understand what I'm doing here, then you understand how the linux
106 * sleep/wakeup mechanism works.
107 *
108 * Two very simple procedures, poll_wait() and poll_freewait() make all the
109 * work. poll_wait() is an inline-function defined in <linux/poll.h>,
110 * as all select/poll functions have to call it to add an entry to the
111 * poll table.
112 */
Adrian Bunk75c96f82005-05-05 16:16:09 -0700113static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
114 poll_table *p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115
116void poll_initwait(struct poll_wqueues *pwq)
117{
118 init_poll_funcptr(&pwq->pt, __pollwait);
Tejun Heo5f820f62009-01-06 14:40:59 -0800119 pwq->polling_task = current;
Guillaume Knispelb2add732009-08-15 19:30:24 +0200120 pwq->triggered = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121 pwq->error = 0;
122 pwq->table = NULL;
Andi Kleen70674f92006-03-28 01:56:33 -0800123 pwq->inline_index = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125EXPORT_SYMBOL(poll_initwait);
126
Andi Kleen70674f92006-03-28 01:56:33 -0800127static void free_poll_entry(struct poll_table_entry *entry)
128{
WANG Congccf67802007-05-09 07:10:02 +0200129 remove_wait_queue(entry->wait_address, &entry->wait);
Andi Kleen70674f92006-03-28 01:56:33 -0800130 fput(entry->filp);
131}
132
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133void poll_freewait(struct poll_wqueues *pwq)
134{
135 struct poll_table_page * p = pwq->table;
Andi Kleen70674f92006-03-28 01:56:33 -0800136 int i;
137 for (i = 0; i < pwq->inline_index; i++)
138 free_poll_entry(pwq->inline_entries + i);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 while (p) {
140 struct poll_table_entry * entry;
141 struct poll_table_page *old;
142
143 entry = p->entry;
144 do {
145 entry--;
Andi Kleen70674f92006-03-28 01:56:33 -0800146 free_poll_entry(entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147 } while (entry > p->entries);
148 old = p;
149 p = p->next;
150 free_page((unsigned long) old);
151 }
152}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153EXPORT_SYMBOL(poll_freewait);
154
Tejun Heo5f820f62009-01-06 14:40:59 -0800155static struct poll_table_entry *poll_get_entry(struct poll_wqueues *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157 struct poll_table_page *table = p->table;
158
Andi Kleen70674f92006-03-28 01:56:33 -0800159 if (p->inline_index < N_INLINE_POLL_ENTRIES)
160 return p->inline_entries + p->inline_index++;
161
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162 if (!table || POLL_TABLE_FULL(table)) {
163 struct poll_table_page *new_table;
164
165 new_table = (struct poll_table_page *) __get_free_page(GFP_KERNEL);
166 if (!new_table) {
167 p->error = -ENOMEM;
Andi Kleen70674f92006-03-28 01:56:33 -0800168 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 }
170 new_table->entry = new_table->entries;
171 new_table->next = table;
172 p->table = new_table;
173 table = new_table;
174 }
175
Andi Kleen70674f92006-03-28 01:56:33 -0800176 return table->entry++;
177}
178
Eric Dumazet4938d7e2009-06-16 15:33:36 -0700179static int __pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key)
Tejun Heo5f820f62009-01-06 14:40:59 -0800180{
181 struct poll_wqueues *pwq = wait->private;
182 DECLARE_WAITQUEUE(dummy_wait, pwq->polling_task);
183
184 /*
185 * Although this function is called under waitqueue lock, LOCK
186 * doesn't imply write barrier and the users expect write
187 * barrier semantics on wakeup functions. The following
188 * smp_wmb() is equivalent to smp_wmb() in try_to_wake_up()
189 * and is paired with set_mb() in poll_schedule_timeout.
190 */
191 smp_wmb();
192 pwq->triggered = 1;
193
194 /*
195 * Perform the default wake up operation using a dummy
196 * waitqueue.
197 *
198 * TODO: This is hacky but there currently is no interface to
199 * pass in @sync. @sync is scheduled to be removed and once
200 * that happens, wake_up_process() can be used directly.
201 */
202 return default_wake_function(&dummy_wait, mode, sync, key);
203}
204
Eric Dumazet4938d7e2009-06-16 15:33:36 -0700205static int pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key)
206{
207 struct poll_table_entry *entry;
208
209 entry = container_of(wait, struct poll_table_entry, wait);
210 if (key && !((unsigned long)key & entry->key))
211 return 0;
212 return __pollwake(wait, mode, sync, key);
213}
214
Andi Kleen70674f92006-03-28 01:56:33 -0800215/* Add a new entry */
216static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
217 poll_table *p)
218{
Tejun Heo5f820f62009-01-06 14:40:59 -0800219 struct poll_wqueues *pwq = container_of(p, struct poll_wqueues, pt);
220 struct poll_table_entry *entry = poll_get_entry(pwq);
Andi Kleen70674f92006-03-28 01:56:33 -0800221 if (!entry)
222 return;
223 get_file(filp);
224 entry->filp = filp;
225 entry->wait_address = wait_address;
Eric Dumazet4938d7e2009-06-16 15:33:36 -0700226 entry->key = p->key;
Tejun Heo5f820f62009-01-06 14:40:59 -0800227 init_waitqueue_func_entry(&entry->wait, pollwake);
228 entry->wait.private = pwq;
WANG Congccf67802007-05-09 07:10:02 +0200229 add_wait_queue(wait_address, &entry->wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230}
231
Tejun Heo5f820f62009-01-06 14:40:59 -0800232int poll_schedule_timeout(struct poll_wqueues *pwq, int state,
233 ktime_t *expires, unsigned long slack)
234{
235 int rc = -EINTR;
236
237 set_current_state(state);
238 if (!pwq->triggered)
239 rc = schedule_hrtimeout_range(expires, slack, HRTIMER_MODE_ABS);
240 __set_current_state(TASK_RUNNING);
241
242 /*
243 * Prepare for the next iteration.
244 *
245 * The following set_mb() serves two purposes. First, it's
246 * the counterpart rmb of the wmb in pollwake() such that data
247 * written before wake up is always visible after wake up.
248 * Second, the full barrier guarantees that triggered clearing
249 * doesn't pass event check of the next iteration. Note that
250 * this problem doesn't exist for the first iteration as
251 * add_wait_queue() has full barrier semantics.
252 */
253 set_mb(pwq->triggered, 0);
254
255 return rc;
256}
257EXPORT_SYMBOL(poll_schedule_timeout);
258
Thomas Gleixnerb773ad42008-08-31 08:16:57 -0700259/**
260 * poll_select_set_timeout - helper function to setup the timeout value
261 * @to: pointer to timespec variable for the final timeout
262 * @sec: seconds (from user space)
263 * @nsec: nanoseconds (from user space)
264 *
265 * Note, we do not use a timespec for the user space value here, That
266 * way we can use the function for timeval and compat interfaces as well.
267 *
268 * Returns -EINVAL if sec/nsec are not normalized. Otherwise 0.
269 */
270int poll_select_set_timeout(struct timespec *to, long sec, long nsec)
271{
272 struct timespec ts = {.tv_sec = sec, .tv_nsec = nsec};
273
274 if (!timespec_valid(&ts))
275 return -EINVAL;
276
277 /* Optimize for the zero timeout value here */
278 if (!sec && !nsec) {
279 to->tv_sec = to->tv_nsec = 0;
280 } else {
281 ktime_get_ts(to);
282 *to = timespec_add_safe(*to, ts);
283 }
284 return 0;
285}
286
287static int poll_select_copy_remaining(struct timespec *end_time, void __user *p,
288 int timeval, int ret)
289{
290 struct timespec rts;
291 struct timeval rtv;
292
293 if (!p)
294 return ret;
295
296 if (current->personality & STICKY_TIMEOUTS)
297 goto sticky;
298
299 /* No update for zero timeout */
300 if (!end_time->tv_sec && !end_time->tv_nsec)
301 return ret;
302
303 ktime_get_ts(&rts);
304 rts = timespec_sub(*end_time, rts);
305 if (rts.tv_sec < 0)
306 rts.tv_sec = rts.tv_nsec = 0;
307
308 if (timeval) {
309 rtv.tv_sec = rts.tv_sec;
310 rtv.tv_usec = rts.tv_nsec / NSEC_PER_USEC;
311
312 if (!copy_to_user(p, &rtv, sizeof(rtv)))
313 return ret;
314
315 } else if (!copy_to_user(p, &rts, sizeof(rts)))
316 return ret;
317
318 /*
319 * If an application puts its timeval in read-only memory, we
320 * don't want the Linux-specific update to the timeval to
321 * cause a fault after the select has completed
322 * successfully. However, because we're not updating the
323 * timeval, we can't restart the system call.
324 */
325
326sticky:
327 if (ret == -ERESTARTNOHAND)
328 ret = -EINTR;
329 return ret;
330}
331
Linus Torvalds1da177e2005-04-16 15:20:36 -0700332#define FDS_IN(fds, n) (fds->in + n)
333#define FDS_OUT(fds, n) (fds->out + n)
334#define FDS_EX(fds, n) (fds->ex + n)
335
336#define BITS(fds, n) (*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n))
337
338static int max_select_fd(unsigned long n, fd_set_bits *fds)
339{
340 unsigned long *open_fds;
341 unsigned long set;
342 int max;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700343 struct fdtable *fdt;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344
345 /* handle last in-complete long-word first */
346 set = ~(~0UL << (n & (__NFDBITS-1)));
347 n /= __NFDBITS;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700348 fdt = files_fdtable(current->files);
349 open_fds = fdt->open_fds->fds_bits+n;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 max = 0;
351 if (set) {
352 set &= BITS(fds, n);
353 if (set) {
354 if (!(set & ~*open_fds))
355 goto get_max;
356 return -EBADF;
357 }
358 }
359 while (n) {
360 open_fds--;
361 n--;
362 set = BITS(fds, n);
363 if (!set)
364 continue;
365 if (set & ~*open_fds)
366 return -EBADF;
367 if (max)
368 continue;
369get_max:
370 do {
371 max++;
372 set >>= 1;
373 } while (set);
374 max += n * __NFDBITS;
375 }
376
377 return max;
378}
379
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380#define POLLIN_SET (POLLRDNORM | POLLRDBAND | POLLIN | POLLHUP | POLLERR)
381#define POLLOUT_SET (POLLWRBAND | POLLWRNORM | POLLOUT | POLLERR)
382#define POLLEX_SET (POLLPRI)
383
Eric Dumazet4938d7e2009-06-16 15:33:36 -0700384static inline void wait_key_set(poll_table *wait, unsigned long in,
385 unsigned long out, unsigned long bit)
386{
387 if (wait) {
388 wait->key = POLLEX_SET;
389 if (in & bit)
390 wait->key |= POLLIN_SET;
391 if (out & bit)
392 wait->key |= POLLOUT_SET;
393 }
394}
395
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700396int do_select(int n, fd_set_bits *fds, struct timespec *end_time)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397{
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700398 ktime_t expire, *to = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399 struct poll_wqueues table;
400 poll_table *wait;
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700401 int retval, i, timed_out = 0;
Arjan van de Ven90d6e242008-09-01 15:55:35 -0700402 unsigned long slack = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403
Dipankar Sarmab8359962005-09-09 13:04:14 -0700404 rcu_read_lock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405 retval = max_select_fd(n, fds);
Dipankar Sarmab8359962005-09-09 13:04:14 -0700406 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700407
408 if (retval < 0)
409 return retval;
410 n = retval;
411
412 poll_initwait(&table);
413 wait = &table.pt;
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700414 if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 wait = NULL;
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700416 timed_out = 1;
417 }
418
Arjan van de Ven96d2ab42008-09-07 16:08:55 -0700419 if (end_time && !timed_out)
Arjan van de Ven90d6e242008-09-01 15:55:35 -0700420 slack = estimate_accuracy(end_time);
421
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422 retval = 0;
423 for (;;) {
424 unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp;
425
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426 inp = fds->in; outp = fds->out; exp = fds->ex;
427 rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex;
428
429 for (i = 0; i < n; ++rinp, ++routp, ++rexp) {
430 unsigned long in, out, ex, all_bits, bit = 1, mask, j;
431 unsigned long res_in = 0, res_out = 0, res_ex = 0;
Arjan van de Ven99ac48f2006-03-28 01:56:41 -0800432 const struct file_operations *f_op = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 struct file *file = NULL;
434
435 in = *inp++; out = *outp++; ex = *exp++;
436 all_bits = in | out | ex;
437 if (all_bits == 0) {
438 i += __NFDBITS;
439 continue;
440 }
441
442 for (j = 0; j < __NFDBITS; ++j, ++i, bit <<= 1) {
Eric Dumazete4a1f122006-03-28 01:56:34 -0800443 int fput_needed;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700444 if (i >= n)
445 break;
446 if (!(bit & all_bits))
447 continue;
Eric Dumazete4a1f122006-03-28 01:56:34 -0800448 file = fget_light(i, &fput_needed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449 if (file) {
450 f_op = file->f_op;
451 mask = DEFAULT_POLLMASK;
Eric Dumazet4938d7e2009-06-16 15:33:36 -0700452 if (f_op && f_op->poll) {
453 wait_key_set(wait, in, out, bit);
454 mask = (*f_op->poll)(file, wait);
455 }
Eric Dumazete4a1f122006-03-28 01:56:34 -0800456 fput_light(file, fput_needed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700457 if ((mask & POLLIN_SET) && (in & bit)) {
458 res_in |= bit;
459 retval++;
Eric Dumazet4938d7e2009-06-16 15:33:36 -0700460 wait = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461 }
462 if ((mask & POLLOUT_SET) && (out & bit)) {
463 res_out |= bit;
464 retval++;
Eric Dumazet4938d7e2009-06-16 15:33:36 -0700465 wait = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466 }
467 if ((mask & POLLEX_SET) && (ex & bit)) {
468 res_ex |= bit;
469 retval++;
Eric Dumazet4938d7e2009-06-16 15:33:36 -0700470 wait = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471 }
472 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473 }
474 if (res_in)
475 *rinp = res_in;
476 if (res_out)
477 *routp = res_out;
478 if (res_ex)
479 *rexp = res_ex;
Linus Torvalds55d85382008-06-22 12:23:15 -0700480 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481 }
482 wait = NULL;
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700483 if (retval || timed_out || signal_pending(current))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484 break;
Pavel Machekf5264482008-04-21 22:15:06 +0000485 if (table.error) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486 retval = table.error;
487 break;
488 }
David Woodhouse9f729492006-01-18 17:44:05 -0800489
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700490 /*
491 * If this is the first loop and we have a timeout
492 * given, then we convert to ktime_t and set the to
493 * pointer to the expiry value.
494 */
495 if (end_time && !to) {
496 expire = timespec_to_ktime(*end_time);
497 to = &expire;
David Woodhouse9f729492006-01-18 17:44:05 -0800498 }
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700499
Tejun Heo5f820f62009-01-06 14:40:59 -0800500 if (!poll_schedule_timeout(&table, TASK_INTERRUPTIBLE,
501 to, slack))
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700502 timed_out = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504
505 poll_freewait(&table);
506
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 return retval;
508}
509
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510/*
511 * We can actually return ERESTARTSYS instead of EINTR, but I'd
512 * like to be certain this leads to no problems. So I return
513 * EINTR just for safety.
514 *
515 * Update: ERESTARTSYS breaks at least the xview clock binary, so
516 * I'm trying ERESTARTNOHAND which restart only when you want to.
517 */
518#define MAX_SELECT_SECONDS \
519 ((unsigned long) (MAX_SCHEDULE_TIMEOUT / HZ)-1)
520
Al Viroa2dcb442008-04-23 14:05:15 -0400521int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700522 fd_set __user *exp, struct timespec *end_time)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523{
524 fd_set_bits fds;
Andrew Morton29ff2db2006-04-10 22:52:46 -0700525 void *bits;
Vadim Lobanovbbea9f62006-12-10 02:21:12 -0800526 int ret, max_fds;
Mitchell Blank Jrb04eb6a2006-04-10 22:54:08 -0700527 unsigned int size;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700528 struct fdtable *fdt;
Andi Kleen70674f92006-03-28 01:56:33 -0800529 /* Allocate small arguments on the stack to save memory and be faster */
Jes Sorensen30c14e42006-03-31 11:18:57 -0500530 long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532 ret = -EINVAL;
533 if (n < 0)
534 goto out_nofds;
535
Vadim Lobanovbbea9f62006-12-10 02:21:12 -0800536 /* max_fds can increase, so grab it once to avoid race */
Dipankar Sarmab8359962005-09-09 13:04:14 -0700537 rcu_read_lock();
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700538 fdt = files_fdtable(current->files);
Vadim Lobanovbbea9f62006-12-10 02:21:12 -0800539 max_fds = fdt->max_fds;
Dipankar Sarmab8359962005-09-09 13:04:14 -0700540 rcu_read_unlock();
Vadim Lobanovbbea9f62006-12-10 02:21:12 -0800541 if (n > max_fds)
542 n = max_fds;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543
544 /*
545 * We need 6 bitmaps (in/out/ex for both incoming and outgoing),
546 * since we used fdset we need to allocate memory in units of
547 * long-words.
548 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549 size = FDS_BYTES(n);
Mitchell Blank Jrb04eb6a2006-04-10 22:54:08 -0700550 bits = stack_fds;
551 if (size > sizeof(stack_fds) / 6) {
552 /* Not enough space in on-stack array; must use kmalloc */
553 ret = -ENOMEM;
Andi Kleen70674f92006-03-28 01:56:33 -0800554 bits = kmalloc(6 * size, GFP_KERNEL);
Mitchell Blank Jrb04eb6a2006-04-10 22:54:08 -0700555 if (!bits)
556 goto out_nofds;
557 }
Andrew Morton29ff2db2006-04-10 22:52:46 -0700558 fds.in = bits;
559 fds.out = bits + size;
560 fds.ex = bits + 2*size;
561 fds.res_in = bits + 3*size;
562 fds.res_out = bits + 4*size;
563 fds.res_ex = bits + 5*size;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564
565 if ((ret = get_fd_set(n, inp, fds.in)) ||
566 (ret = get_fd_set(n, outp, fds.out)) ||
567 (ret = get_fd_set(n, exp, fds.ex)))
568 goto out;
569 zero_fd_set(n, fds.res_in);
570 zero_fd_set(n, fds.res_out);
571 zero_fd_set(n, fds.res_ex);
572
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700573 ret = do_select(n, &fds, end_time);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574
575 if (ret < 0)
576 goto out;
577 if (!ret) {
578 ret = -ERESTARTNOHAND;
579 if (signal_pending(current))
580 goto out;
581 ret = 0;
582 }
583
584 if (set_fd_set(n, inp, fds.res_in) ||
585 set_fd_set(n, outp, fds.res_out) ||
586 set_fd_set(n, exp, fds.res_ex))
587 ret = -EFAULT;
588
589out:
Andi Kleen70674f92006-03-28 01:56:33 -0800590 if (bits != stack_fds)
591 kfree(bits);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592out_nofds:
593 return ret;
594}
595
Heiko Carstens5a8a82b2009-01-14 14:14:25 +0100596SYSCALL_DEFINE5(select, int, n, fd_set __user *, inp, fd_set __user *, outp,
597 fd_set __user *, exp, struct timeval __user *, tvp)
David Woodhouse9f729492006-01-18 17:44:05 -0800598{
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700599 struct timespec end_time, *to = NULL;
David Woodhouse9f729492006-01-18 17:44:05 -0800600 struct timeval tv;
601 int ret;
602
603 if (tvp) {
604 if (copy_from_user(&tv, tvp, sizeof(tv)))
605 return -EFAULT;
606
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700607 to = &end_time;
Arjan van de Ven4d36a9e2008-10-25 12:41:41 -0700608 if (poll_select_set_timeout(to,
609 tv.tv_sec + (tv.tv_usec / USEC_PER_SEC),
610 (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC))
David Woodhouse9f729492006-01-18 17:44:05 -0800611 return -EINVAL;
David Woodhouse9f729492006-01-18 17:44:05 -0800612 }
613
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700614 ret = core_sys_select(n, inp, outp, exp, to);
615 ret = poll_select_copy_remaining(&end_time, tvp, 1, ret);
David Woodhouse9f729492006-01-18 17:44:05 -0800616
617 return ret;
618}
619
Roland McGrathf3de2722008-04-30 00:53:09 -0700620#ifdef HAVE_SET_RESTORE_SIGMASK
Heiko Carstensc9da9f22009-01-14 14:13:57 +0100621static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp,
622 fd_set __user *exp, struct timespec __user *tsp,
623 const sigset_t __user *sigmask, size_t sigsetsize)
David Woodhouse9f729492006-01-18 17:44:05 -0800624{
David Woodhouse9f729492006-01-18 17:44:05 -0800625 sigset_t ksigmask, sigsaved;
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700626 struct timespec ts, end_time, *to = NULL;
David Woodhouse9f729492006-01-18 17:44:05 -0800627 int ret;
628
629 if (tsp) {
630 if (copy_from_user(&ts, tsp, sizeof(ts)))
631 return -EFAULT;
632
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700633 to = &end_time;
634 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
David Woodhouse9f729492006-01-18 17:44:05 -0800635 return -EINVAL;
David Woodhouse9f729492006-01-18 17:44:05 -0800636 }
637
638 if (sigmask) {
639 /* XXX: Don't preclude handling different sized sigset_t's. */
640 if (sigsetsize != sizeof(sigset_t))
641 return -EINVAL;
642 if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask)))
643 return -EFAULT;
644
645 sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
646 sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
647 }
648
Bernd Schmidt62568512009-01-13 22:14:48 +0100649 ret = core_sys_select(n, inp, outp, exp, to);
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700650 ret = poll_select_copy_remaining(&end_time, tsp, 0, ret);
David Woodhouse9f729492006-01-18 17:44:05 -0800651
652 if (ret == -ERESTARTNOHAND) {
653 /*
654 * Don't restore the signal mask yet. Let do_signal() deliver
655 * the signal on the way back to userspace, before the signal
656 * mask is restored.
657 */
658 if (sigmask) {
659 memcpy(&current->saved_sigmask, &sigsaved,
660 sizeof(sigsaved));
Roland McGrath4e4c22c2008-04-30 00:53:06 -0700661 set_restore_sigmask();
David Woodhouse9f729492006-01-18 17:44:05 -0800662 }
663 } else if (sigmask)
664 sigprocmask(SIG_SETMASK, &sigsaved, NULL);
665
666 return ret;
667}
668
669/*
670 * Most architectures can't handle 7-argument syscalls. So we provide a
671 * 6-argument version where the sixth argument is a pointer to a structure
672 * which has a pointer to the sigset_t itself followed by a size_t containing
673 * the sigset size.
674 */
Heiko Carstensd4e82042009-01-14 14:14:34 +0100675SYSCALL_DEFINE6(pselect6, int, n, fd_set __user *, inp, fd_set __user *, outp,
676 fd_set __user *, exp, struct timespec __user *, tsp,
677 void __user *, sig)
David Woodhouse9f729492006-01-18 17:44:05 -0800678{
679 size_t sigsetsize = 0;
680 sigset_t __user *up = NULL;
681
682 if (sig) {
683 if (!access_ok(VERIFY_READ, sig, sizeof(void *)+sizeof(size_t))
Al Viroe110ab92006-02-01 05:26:09 -0500684 || __get_user(up, (sigset_t __user * __user *)sig)
David Woodhouse9f729492006-01-18 17:44:05 -0800685 || __get_user(sigsetsize,
Al Viroe110ab92006-02-01 05:26:09 -0500686 (size_t __user *)(sig+sizeof(void *))))
David Woodhouse9f729492006-01-18 17:44:05 -0800687 return -EFAULT;
688 }
689
Heiko Carstensc9da9f22009-01-14 14:13:57 +0100690 return do_pselect(n, inp, outp, exp, tsp, up, sigsetsize);
David Woodhouse9f729492006-01-18 17:44:05 -0800691}
Roland McGrathf3de2722008-04-30 00:53:09 -0700692#endif /* HAVE_SET_RESTORE_SIGMASK */
David Woodhouse9f729492006-01-18 17:44:05 -0800693
Christoph Hellwig5d0e5282010-03-10 15:21:13 -0800694#ifdef __ARCH_WANT_SYS_OLD_SELECT
695struct sel_arg_struct {
696 unsigned long n;
697 fd_set __user *inp, *outp, *exp;
698 struct timeval __user *tvp;
699};
700
701SYSCALL_DEFINE1(old_select, struct sel_arg_struct __user *, arg)
702{
703 struct sel_arg_struct a;
704
705 if (copy_from_user(&a, arg, sizeof(a)))
706 return -EFAULT;
707 return sys_select(a.n, a.inp, a.outp, a.exp, a.tvp);
708}
709#endif
710
Linus Torvalds1da177e2005-04-16 15:20:36 -0700711struct poll_list {
712 struct poll_list *next;
713 int len;
714 struct pollfd entries[0];
715};
716
717#define POLLFD_PER_PAGE ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd))
718
Vadim Lobanov4a4b69f2006-06-23 02:05:16 -0700719/*
720 * Fish for pollable events on the pollfd->fd file descriptor. We're only
721 * interested in events matching the pollfd->events mask, and the result
722 * matching that mask is both recorded in pollfd->revents and returned. The
723 * pwait poll_table will be used by the fd-provided poll handler for waiting,
724 * if non-NULL.
725 */
726static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727{
Vadim Lobanov4a4b69f2006-06-23 02:05:16 -0700728 unsigned int mask;
729 int fd;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730
Vadim Lobanov4a4b69f2006-06-23 02:05:16 -0700731 mask = 0;
732 fd = pollfd->fd;
733 if (fd >= 0) {
734 int fput_needed;
735 struct file * file;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736
Vadim Lobanov4a4b69f2006-06-23 02:05:16 -0700737 file = fget_light(fd, &fput_needed);
738 mask = POLLNVAL;
739 if (file != NULL) {
740 mask = DEFAULT_POLLMASK;
Eric Dumazet4938d7e2009-06-16 15:33:36 -0700741 if (file->f_op && file->f_op->poll) {
742 if (pwait)
743 pwait->key = pollfd->events |
744 POLLERR | POLLHUP;
Vadim Lobanov4a4b69f2006-06-23 02:05:16 -0700745 mask = file->f_op->poll(file, pwait);
Eric Dumazet4938d7e2009-06-16 15:33:36 -0700746 }
Vadim Lobanov4a4b69f2006-06-23 02:05:16 -0700747 /* Mask out unneeded events. */
748 mask &= pollfd->events | POLLERR | POLLHUP;
749 fput_light(file, fput_needed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700751 }
Vadim Lobanov4a4b69f2006-06-23 02:05:16 -0700752 pollfd->revents = mask;
753
754 return mask;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700755}
756
757static int do_poll(unsigned int nfds, struct poll_list *list,
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700758 struct poll_wqueues *wait, struct timespec *end_time)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700759{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700760 poll_table* pt = &wait->pt;
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700761 ktime_t expire, *to = NULL;
762 int timed_out = 0, count = 0;
Arjan van de Ven90d6e242008-09-01 15:55:35 -0700763 unsigned long slack = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764
David Woodhouse9f729492006-01-18 17:44:05 -0800765 /* Optimise the no-wait case */
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700766 if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700767 pt = NULL;
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700768 timed_out = 1;
769 }
Oleg Nesterov9bf084f2007-10-16 23:26:18 -0700770
Arjan van de Ven96d2ab42008-09-07 16:08:55 -0700771 if (end_time && !timed_out)
Arjan van de Ven90d6e242008-09-01 15:55:35 -0700772 slack = estimate_accuracy(end_time);
773
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774 for (;;) {
775 struct poll_list *walk;
David Woodhouse9f729492006-01-18 17:44:05 -0800776
Vadim Lobanov4a4b69f2006-06-23 02:05:16 -0700777 for (walk = list; walk != NULL; walk = walk->next) {
778 struct pollfd * pfd, * pfd_end;
779
780 pfd = walk->entries;
781 pfd_end = pfd + walk->len;
782 for (; pfd != pfd_end; pfd++) {
783 /*
784 * Fish for events. If we found one, record it
785 * and kill the poll_table, so we don't
786 * needlessly register any other waiters after
787 * this. They'll get immediately deregistered
788 * when we break out and return.
789 */
790 if (do_pollfd(pfd, pt)) {
791 count++;
792 pt = NULL;
793 }
794 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700795 }
Vadim Lobanov4a4b69f2006-06-23 02:05:16 -0700796 /*
797 * All waiters have already been registered, so don't provide
798 * a poll_table to them on the next loop iteration.
799 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800 pt = NULL;
Oleg Nesterov9bf084f2007-10-16 23:26:18 -0700801 if (!count) {
802 count = wait->error;
803 if (signal_pending(current))
804 count = -EINTR;
805 }
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700806 if (count || timed_out)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700807 break;
David Woodhouse9f729492006-01-18 17:44:05 -0800808
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700809 /*
810 * If this is the first loop and we have a timeout
811 * given, then we convert to ktime_t and set the to
812 * pointer to the expiry value.
813 */
814 if (end_time && !to) {
815 expire = timespec_to_ktime(*end_time);
816 to = &expire;
David Woodhouse9f729492006-01-18 17:44:05 -0800817 }
818
Tejun Heo5f820f62009-01-06 14:40:59 -0800819 if (!poll_schedule_timeout(wait, TASK_INTERRUPTIBLE, to, slack))
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700820 timed_out = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700821 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700822 return count;
823}
824
Andi Kleen70674f92006-03-28 01:56:33 -0800825#define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \
826 sizeof(struct pollfd))
827
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700828int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,
829 struct timespec *end_time)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700830{
831 struct poll_wqueues table;
Oleg Nesterov252e5722007-10-16 23:26:17 -0700832 int err = -EFAULT, fdcount, len, size;
Jes Sorensen30c14e42006-03-31 11:18:57 -0500833 /* Allocate small arguments on the stack to save memory and be
834 faster - use long to make sure the buffer is aligned properly
835 on 64 bit archs to avoid unaligned access */
836 long stack_pps[POLL_STACK_ALLOC/sizeof(long)];
Oleg Nesterov252e5722007-10-16 23:26:17 -0700837 struct poll_list *const head = (struct poll_list *)stack_pps;
838 struct poll_list *walk = head;
839 unsigned long todo = nfds;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840
Jiri Slabyd554ed892010-03-05 13:42:42 -0800841 if (nfds > rlimit(RLIMIT_NOFILE))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842 return -EINVAL;
843
Oleg Nesterov252e5722007-10-16 23:26:17 -0700844 len = min_t(unsigned int, nfds, N_STACK_PPS);
845 for (;;) {
846 walk->next = NULL;
847 walk->len = len;
848 if (!len)
849 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850
Oleg Nesterov252e5722007-10-16 23:26:17 -0700851 if (copy_from_user(walk->entries, ufds + nfds-todo,
852 sizeof(struct pollfd) * walk->len))
853 goto out_fds;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854
Oleg Nesterov252e5722007-10-16 23:26:17 -0700855 todo -= walk->len;
856 if (!todo)
857 break;
858
859 len = min(todo, POLLFD_PER_PAGE);
860 size = sizeof(struct poll_list) + sizeof(struct pollfd) * len;
861 walk = walk->next = kmalloc(size, GFP_KERNEL);
862 if (!walk) {
863 err = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700864 goto out_fds;
865 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700866 }
David Woodhouse9f729492006-01-18 17:44:05 -0800867
Oleg Nesterov252e5722007-10-16 23:26:17 -0700868 poll_initwait(&table);
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700869 fdcount = do_poll(nfds, head, &table, end_time);
Oleg Nesterov252e5722007-10-16 23:26:17 -0700870 poll_freewait(&table);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700871
Oleg Nesterov252e5722007-10-16 23:26:17 -0700872 for (walk = head; walk; walk = walk->next) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700873 struct pollfd *fds = walk->entries;
874 int j;
875
Oleg Nesterov252e5722007-10-16 23:26:17 -0700876 for (j = 0; j < walk->len; j++, ufds++)
877 if (__put_user(fds[j].revents, &ufds->revents))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700878 goto out_fds;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879 }
Oleg Nesterov252e5722007-10-16 23:26:17 -0700880
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881 err = fdcount;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700882out_fds:
Oleg Nesterov252e5722007-10-16 23:26:17 -0700883 walk = head->next;
884 while (walk) {
885 struct poll_list *pos = walk;
886 walk = walk->next;
887 kfree(pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700888 }
Oleg Nesterov252e5722007-10-16 23:26:17 -0700889
Linus Torvalds1da177e2005-04-16 15:20:36 -0700890 return err;
891}
David Woodhouse9f729492006-01-18 17:44:05 -0800892
Chris Wright3075d9d2007-10-16 23:27:18 -0700893static long do_restart_poll(struct restart_block *restart_block)
894{
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700895 struct pollfd __user *ufds = restart_block->poll.ufds;
896 int nfds = restart_block->poll.nfds;
897 struct timespec *to = NULL, end_time;
Chris Wright3075d9d2007-10-16 23:27:18 -0700898 int ret;
899
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700900 if (restart_block->poll.has_timeout) {
901 end_time.tv_sec = restart_block->poll.tv_sec;
902 end_time.tv_nsec = restart_block->poll.tv_nsec;
903 to = &end_time;
904 }
905
906 ret = do_sys_poll(ufds, nfds, to);
907
Chris Wright3075d9d2007-10-16 23:27:18 -0700908 if (ret == -EINTR) {
909 restart_block->fn = do_restart_poll;
Chris Wright3075d9d2007-10-16 23:27:18 -0700910 ret = -ERESTART_RESTARTBLOCK;
911 }
912 return ret;
913}
914
Heiko Carstens5a8a82b2009-01-14 14:14:25 +0100915SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds,
916 long, timeout_msecs)
David Woodhouse9f729492006-01-18 17:44:05 -0800917{
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700918 struct timespec end_time, *to = NULL;
Chris Wright3075d9d2007-10-16 23:27:18 -0700919 int ret;
David Woodhouse9f729492006-01-18 17:44:05 -0800920
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700921 if (timeout_msecs >= 0) {
922 to = &end_time;
923 poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC,
924 NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC));
David Woodhouse9f729492006-01-18 17:44:05 -0800925 }
926
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700927 ret = do_sys_poll(ufds, nfds, to);
928
Chris Wright3075d9d2007-10-16 23:27:18 -0700929 if (ret == -EINTR) {
930 struct restart_block *restart_block;
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700931
Chris Wright3075d9d2007-10-16 23:27:18 -0700932 restart_block = &current_thread_info()->restart_block;
933 restart_block->fn = do_restart_poll;
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700934 restart_block->poll.ufds = ufds;
935 restart_block->poll.nfds = nfds;
936
937 if (timeout_msecs >= 0) {
938 restart_block->poll.tv_sec = end_time.tv_sec;
939 restart_block->poll.tv_nsec = end_time.tv_nsec;
940 restart_block->poll.has_timeout = 1;
941 } else
942 restart_block->poll.has_timeout = 0;
943
Chris Wright3075d9d2007-10-16 23:27:18 -0700944 ret = -ERESTART_RESTARTBLOCK;
945 }
946 return ret;
David Woodhouse9f729492006-01-18 17:44:05 -0800947}
948
Roland McGrathf3de2722008-04-30 00:53:09 -0700949#ifdef HAVE_SET_RESTORE_SIGMASK
Heiko Carstensd4e82042009-01-14 14:14:34 +0100950SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds,
951 struct timespec __user *, tsp, const sigset_t __user *, sigmask,
952 size_t, sigsetsize)
David Woodhouse9f729492006-01-18 17:44:05 -0800953{
954 sigset_t ksigmask, sigsaved;
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700955 struct timespec ts, end_time, *to = NULL;
David Woodhouse9f729492006-01-18 17:44:05 -0800956 int ret;
957
958 if (tsp) {
959 if (copy_from_user(&ts, tsp, sizeof(ts)))
960 return -EFAULT;
961
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700962 to = &end_time;
963 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
964 return -EINVAL;
David Woodhouse9f729492006-01-18 17:44:05 -0800965 }
966
967 if (sigmask) {
968 /* XXX: Don't preclude handling different sized sigset_t's. */
969 if (sigsetsize != sizeof(sigset_t))
970 return -EINVAL;
971 if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask)))
972 return -EFAULT;
973
974 sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
975 sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
976 }
977
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700978 ret = do_sys_poll(ufds, nfds, to);
David Woodhouse9f729492006-01-18 17:44:05 -0800979
980 /* We can restart this syscall, usually */
981 if (ret == -EINTR) {
982 /*
983 * Don't restore the signal mask yet. Let do_signal() deliver
984 * the signal on the way back to userspace, before the signal
985 * mask is restored.
986 */
987 if (sigmask) {
988 memcpy(&current->saved_sigmask, &sigsaved,
989 sizeof(sigsaved));
Roland McGrath4e4c22c2008-04-30 00:53:06 -0700990 set_restore_sigmask();
David Woodhouse9f729492006-01-18 17:44:05 -0800991 }
992 ret = -ERESTARTNOHAND;
993 } else if (sigmask)
994 sigprocmask(SIG_SETMASK, &sigsaved, NULL);
995
Arjan van de Ven8ff3e8e2008-08-31 08:26:40 -0700996 ret = poll_select_copy_remaining(&end_time, tsp, 0, ret);
David Woodhouse9f729492006-01-18 17:44:05 -0800997
998 return ret;
999}
Roland McGrathf3de2722008-04-30 00:53:09 -07001000#endif /* HAVE_SET_RESTORE_SIGMASK */