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Commit | Line | Data |
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1da177e4 LT |
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 | ||
022a1692 | 17 | #include <linux/kernel.h> |
1da177e4 LT |
18 | #include <linux/syscalls.h> |
19 | #include <linux/module.h> | |
20 | #include <linux/slab.h> | |
1da177e4 LT |
21 | #include <linux/poll.h> |
22 | #include <linux/personality.h> /* for STICKY_TIMEOUTS */ | |
23 | #include <linux/file.h> | |
9f3acc31 | 24 | #include <linux/fdtable.h> |
1da177e4 | 25 | #include <linux/fs.h> |
b835996f | 26 | #include <linux/rcupdate.h> |
8ff3e8e8 | 27 | #include <linux/hrtimer.h> |
1da177e4 LT |
28 | |
29 | #include <asm/uaccess.h> | |
30 | ||
90d6e24a AV |
31 | |
32 | /* | |
33 | * Estimate expected accuracy in ns from a timeval. | |
34 | * | |
35 | * After quite a bit of churning around, we've settled on | |
36 | * a simple thing of taking 0.1% of the timeout as the | |
37 | * slack, with a cap of 100 msec. | |
38 | * "nice" tasks get a 0.5% slack instead. | |
39 | * | |
40 | * Consider this comment an open invitation to come up with even | |
41 | * better solutions.. | |
42 | */ | |
43 | ||
96d2ab48 | 44 | static long __estimate_accuracy(struct timespec *tv) |
90d6e24a | 45 | { |
96d2ab48 | 46 | long slack; |
90d6e24a AV |
47 | int divfactor = 1000; |
48 | ||
4ce105d3 | 49 | if (task_nice(current) > 0) |
90d6e24a AV |
50 | divfactor = divfactor / 5; |
51 | ||
52 | slack = tv->tv_nsec / divfactor; | |
53 | slack += tv->tv_sec * (NSEC_PER_SEC/divfactor); | |
54 | ||
55 | if (slack > 100 * NSEC_PER_MSEC) | |
56 | slack = 100 * NSEC_PER_MSEC; | |
96d2ab48 AV |
57 | |
58 | if (slack < 0) | |
59 | slack = 0; | |
90d6e24a AV |
60 | return slack; |
61 | } | |
62 | ||
96d2ab48 | 63 | static long estimate_accuracy(struct timespec *tv) |
90d6e24a AV |
64 | { |
65 | unsigned long ret; | |
66 | struct timespec now; | |
67 | ||
68 | /* | |
69 | * Realtime tasks get a slack of 0 for obvious reasons. | |
70 | */ | |
71 | ||
4ce105d3 | 72 | if (rt_task(current)) |
90d6e24a AV |
73 | return 0; |
74 | ||
75 | ktime_get_ts(&now); | |
76 | now = timespec_sub(*tv, now); | |
77 | ret = __estimate_accuracy(&now); | |
78 | if (ret < current->timer_slack_ns) | |
79 | return current->timer_slack_ns; | |
80 | return ret; | |
81 | } | |
82 | ||
83 | ||
84 | ||
1da177e4 LT |
85 | struct poll_table_page { |
86 | struct poll_table_page * next; | |
87 | struct poll_table_entry * entry; | |
88 | struct poll_table_entry entries[0]; | |
89 | }; | |
90 | ||
91 | #define POLL_TABLE_FULL(table) \ | |
92 | ((unsigned long)((table)->entry+1) > PAGE_SIZE + (unsigned long)(table)) | |
93 | ||
94 | /* | |
95 | * Ok, Peter made a complicated, but straightforward multiple_wait() function. | |
96 | * I have rewritten this, taking some shortcuts: This code may not be easy to | |
97 | * follow, but it should be free of race-conditions, and it's practical. If you | |
98 | * understand what I'm doing here, then you understand how the linux | |
99 | * sleep/wakeup mechanism works. | |
100 | * | |
101 | * Two very simple procedures, poll_wait() and poll_freewait() make all the | |
102 | * work. poll_wait() is an inline-function defined in <linux/poll.h>, | |
103 | * as all select/poll functions have to call it to add an entry to the | |
104 | * poll table. | |
105 | */ | |
75c96f85 AB |
106 | static void __pollwait(struct file *filp, wait_queue_head_t *wait_address, |
107 | poll_table *p); | |
1da177e4 LT |
108 | |
109 | void poll_initwait(struct poll_wqueues *pwq) | |
110 | { | |
111 | init_poll_funcptr(&pwq->pt, __pollwait); | |
5f820f64 | 112 | pwq->polling_task = current; |
b2add73d | 113 | pwq->triggered = 0; |
1da177e4 LT |
114 | pwq->error = 0; |
115 | pwq->table = NULL; | |
70674f95 | 116 | pwq->inline_index = 0; |
1da177e4 | 117 | } |
1da177e4 LT |
118 | EXPORT_SYMBOL(poll_initwait); |
119 | ||
70674f95 AK |
120 | static void free_poll_entry(struct poll_table_entry *entry) |
121 | { | |
ccf6780d | 122 | remove_wait_queue(entry->wait_address, &entry->wait); |
70674f95 AK |
123 | fput(entry->filp); |
124 | } | |
125 | ||
1da177e4 LT |
126 | void poll_freewait(struct poll_wqueues *pwq) |
127 | { | |
128 | struct poll_table_page * p = pwq->table; | |
70674f95 AK |
129 | int i; |
130 | for (i = 0; i < pwq->inline_index; i++) | |
131 | free_poll_entry(pwq->inline_entries + i); | |
1da177e4 LT |
132 | while (p) { |
133 | struct poll_table_entry * entry; | |
134 | struct poll_table_page *old; | |
135 | ||
136 | entry = p->entry; | |
137 | do { | |
138 | entry--; | |
70674f95 | 139 | free_poll_entry(entry); |
1da177e4 LT |
140 | } while (entry > p->entries); |
141 | old = p; | |
142 | p = p->next; | |
143 | free_page((unsigned long) old); | |
144 | } | |
145 | } | |
1da177e4 LT |
146 | EXPORT_SYMBOL(poll_freewait); |
147 | ||
5f820f64 | 148 | static struct poll_table_entry *poll_get_entry(struct poll_wqueues *p) |
1da177e4 | 149 | { |
1da177e4 LT |
150 | struct poll_table_page *table = p->table; |
151 | ||
70674f95 AK |
152 | if (p->inline_index < N_INLINE_POLL_ENTRIES) |
153 | return p->inline_entries + p->inline_index++; | |
154 | ||
1da177e4 LT |
155 | if (!table || POLL_TABLE_FULL(table)) { |
156 | struct poll_table_page *new_table; | |
157 | ||
158 | new_table = (struct poll_table_page *) __get_free_page(GFP_KERNEL); | |
159 | if (!new_table) { | |
160 | p->error = -ENOMEM; | |
70674f95 | 161 | return NULL; |
1da177e4 LT |
162 | } |
163 | new_table->entry = new_table->entries; | |
164 | new_table->next = table; | |
165 | p->table = new_table; | |
166 | table = new_table; | |
167 | } | |
168 | ||
70674f95 AK |
169 | return table->entry++; |
170 | } | |
171 | ||
4938d7e0 | 172 | static int __pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key) |
5f820f64 TH |
173 | { |
174 | struct poll_wqueues *pwq = wait->private; | |
175 | DECLARE_WAITQUEUE(dummy_wait, pwq->polling_task); | |
176 | ||
177 | /* | |
178 | * Although this function is called under waitqueue lock, LOCK | |
179 | * doesn't imply write barrier and the users expect write | |
180 | * barrier semantics on wakeup functions. The following | |
181 | * smp_wmb() is equivalent to smp_wmb() in try_to_wake_up() | |
182 | * and is paired with set_mb() in poll_schedule_timeout. | |
183 | */ | |
184 | smp_wmb(); | |
185 | pwq->triggered = 1; | |
186 | ||
187 | /* | |
188 | * Perform the default wake up operation using a dummy | |
189 | * waitqueue. | |
190 | * | |
191 | * TODO: This is hacky but there currently is no interface to | |
192 | * pass in @sync. @sync is scheduled to be removed and once | |
193 | * that happens, wake_up_process() can be used directly. | |
194 | */ | |
195 | return default_wake_function(&dummy_wait, mode, sync, key); | |
196 | } | |
197 | ||
4938d7e0 ED |
198 | static int pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key) |
199 | { | |
200 | struct poll_table_entry *entry; | |
201 | ||
202 | entry = container_of(wait, struct poll_table_entry, wait); | |
203 | if (key && !((unsigned long)key & entry->key)) | |
204 | return 0; | |
205 | return __pollwake(wait, mode, sync, key); | |
206 | } | |
207 | ||
70674f95 AK |
208 | /* Add a new entry */ |
209 | static void __pollwait(struct file *filp, wait_queue_head_t *wait_address, | |
210 | poll_table *p) | |
211 | { | |
5f820f64 TH |
212 | struct poll_wqueues *pwq = container_of(p, struct poll_wqueues, pt); |
213 | struct poll_table_entry *entry = poll_get_entry(pwq); | |
70674f95 AK |
214 | if (!entry) |
215 | return; | |
216 | get_file(filp); | |
217 | entry->filp = filp; | |
218 | entry->wait_address = wait_address; | |
4938d7e0 | 219 | entry->key = p->key; |
5f820f64 TH |
220 | init_waitqueue_func_entry(&entry->wait, pollwake); |
221 | entry->wait.private = pwq; | |
ccf6780d | 222 | add_wait_queue(wait_address, &entry->wait); |
1da177e4 LT |
223 | } |
224 | ||
5f820f64 TH |
225 | int poll_schedule_timeout(struct poll_wqueues *pwq, int state, |
226 | ktime_t *expires, unsigned long slack) | |
227 | { | |
228 | int rc = -EINTR; | |
229 | ||
230 | set_current_state(state); | |
231 | if (!pwq->triggered) | |
232 | rc = schedule_hrtimeout_range(expires, slack, HRTIMER_MODE_ABS); | |
233 | __set_current_state(TASK_RUNNING); | |
234 | ||
235 | /* | |
236 | * Prepare for the next iteration. | |
237 | * | |
238 | * The following set_mb() serves two purposes. First, it's | |
239 | * the counterpart rmb of the wmb in pollwake() such that data | |
240 | * written before wake up is always visible after wake up. | |
241 | * Second, the full barrier guarantees that triggered clearing | |
242 | * doesn't pass event check of the next iteration. Note that | |
243 | * this problem doesn't exist for the first iteration as | |
244 | * add_wait_queue() has full barrier semantics. | |
245 | */ | |
246 | set_mb(pwq->triggered, 0); | |
247 | ||
248 | return rc; | |
249 | } | |
250 | EXPORT_SYMBOL(poll_schedule_timeout); | |
251 | ||
b773ad40 TG |
252 | /** |
253 | * poll_select_set_timeout - helper function to setup the timeout value | |
254 | * @to: pointer to timespec variable for the final timeout | |
255 | * @sec: seconds (from user space) | |
256 | * @nsec: nanoseconds (from user space) | |
257 | * | |
258 | * Note, we do not use a timespec for the user space value here, That | |
259 | * way we can use the function for timeval and compat interfaces as well. | |
260 | * | |
261 | * Returns -EINVAL if sec/nsec are not normalized. Otherwise 0. | |
262 | */ | |
263 | int poll_select_set_timeout(struct timespec *to, long sec, long nsec) | |
264 | { | |
265 | struct timespec ts = {.tv_sec = sec, .tv_nsec = nsec}; | |
266 | ||
267 | if (!timespec_valid(&ts)) | |
268 | return -EINVAL; | |
269 | ||
270 | /* Optimize for the zero timeout value here */ | |
271 | if (!sec && !nsec) { | |
272 | to->tv_sec = to->tv_nsec = 0; | |
273 | } else { | |
274 | ktime_get_ts(to); | |
275 | *to = timespec_add_safe(*to, ts); | |
276 | } | |
277 | return 0; | |
278 | } | |
279 | ||
280 | static int poll_select_copy_remaining(struct timespec *end_time, void __user *p, | |
281 | int timeval, int ret) | |
282 | { | |
283 | struct timespec rts; | |
284 | struct timeval rtv; | |
285 | ||
286 | if (!p) | |
287 | return ret; | |
288 | ||
289 | if (current->personality & STICKY_TIMEOUTS) | |
290 | goto sticky; | |
291 | ||
292 | /* No update for zero timeout */ | |
293 | if (!end_time->tv_sec && !end_time->tv_nsec) | |
294 | return ret; | |
295 | ||
296 | ktime_get_ts(&rts); | |
297 | rts = timespec_sub(*end_time, rts); | |
298 | if (rts.tv_sec < 0) | |
299 | rts.tv_sec = rts.tv_nsec = 0; | |
300 | ||
301 | if (timeval) { | |
302 | rtv.tv_sec = rts.tv_sec; | |
303 | rtv.tv_usec = rts.tv_nsec / NSEC_PER_USEC; | |
304 | ||
305 | if (!copy_to_user(p, &rtv, sizeof(rtv))) | |
306 | return ret; | |
307 | ||
308 | } else if (!copy_to_user(p, &rts, sizeof(rts))) | |
309 | return ret; | |
310 | ||
311 | /* | |
312 | * If an application puts its timeval in read-only memory, we | |
313 | * don't want the Linux-specific update to the timeval to | |
314 | * cause a fault after the select has completed | |
315 | * successfully. However, because we're not updating the | |
316 | * timeval, we can't restart the system call. | |
317 | */ | |
318 | ||
319 | sticky: | |
320 | if (ret == -ERESTARTNOHAND) | |
321 | ret = -EINTR; | |
322 | return ret; | |
323 | } | |
324 | ||
1da177e4 LT |
325 | #define FDS_IN(fds, n) (fds->in + n) |
326 | #define FDS_OUT(fds, n) (fds->out + n) | |
327 | #define FDS_EX(fds, n) (fds->ex + n) | |
328 | ||
329 | #define BITS(fds, n) (*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n)) | |
330 | ||
331 | static int max_select_fd(unsigned long n, fd_set_bits *fds) | |
332 | { | |
333 | unsigned long *open_fds; | |
334 | unsigned long set; | |
335 | int max; | |
badf1662 | 336 | struct fdtable *fdt; |
1da177e4 LT |
337 | |
338 | /* handle last in-complete long-word first */ | |
339 | set = ~(~0UL << (n & (__NFDBITS-1))); | |
340 | n /= __NFDBITS; | |
badf1662 DS |
341 | fdt = files_fdtable(current->files); |
342 | open_fds = fdt->open_fds->fds_bits+n; | |
1da177e4 LT |
343 | max = 0; |
344 | if (set) { | |
345 | set &= BITS(fds, n); | |
346 | if (set) { | |
347 | if (!(set & ~*open_fds)) | |
348 | goto get_max; | |
349 | return -EBADF; | |
350 | } | |
351 | } | |
352 | while (n) { | |
353 | open_fds--; | |
354 | n--; | |
355 | set = BITS(fds, n); | |
356 | if (!set) | |
357 | continue; | |
358 | if (set & ~*open_fds) | |
359 | return -EBADF; | |
360 | if (max) | |
361 | continue; | |
362 | get_max: | |
363 | do { | |
364 | max++; | |
365 | set >>= 1; | |
366 | } while (set); | |
367 | max += n * __NFDBITS; | |
368 | } | |
369 | ||
370 | return max; | |
371 | } | |
372 | ||
1da177e4 LT |
373 | #define POLLIN_SET (POLLRDNORM | POLLRDBAND | POLLIN | POLLHUP | POLLERR) |
374 | #define POLLOUT_SET (POLLWRBAND | POLLWRNORM | POLLOUT | POLLERR) | |
375 | #define POLLEX_SET (POLLPRI) | |
376 | ||
4938d7e0 ED |
377 | static inline void wait_key_set(poll_table *wait, unsigned long in, |
378 | unsigned long out, unsigned long bit) | |
379 | { | |
380 | if (wait) { | |
381 | wait->key = POLLEX_SET; | |
382 | if (in & bit) | |
383 | wait->key |= POLLIN_SET; | |
384 | if (out & bit) | |
385 | wait->key |= POLLOUT_SET; | |
386 | } | |
387 | } | |
388 | ||
8ff3e8e8 | 389 | int do_select(int n, fd_set_bits *fds, struct timespec *end_time) |
1da177e4 | 390 | { |
8ff3e8e8 | 391 | ktime_t expire, *to = NULL; |
1da177e4 LT |
392 | struct poll_wqueues table; |
393 | poll_table *wait; | |
8ff3e8e8 | 394 | int retval, i, timed_out = 0; |
90d6e24a | 395 | unsigned long slack = 0; |
1da177e4 | 396 | |
b835996f | 397 | rcu_read_lock(); |
1da177e4 | 398 | retval = max_select_fd(n, fds); |
b835996f | 399 | rcu_read_unlock(); |
1da177e4 LT |
400 | |
401 | if (retval < 0) | |
402 | return retval; | |
403 | n = retval; | |
404 | ||
405 | poll_initwait(&table); | |
406 | wait = &table.pt; | |
8ff3e8e8 | 407 | if (end_time && !end_time->tv_sec && !end_time->tv_nsec) { |
1da177e4 | 408 | wait = NULL; |
8ff3e8e8 AV |
409 | timed_out = 1; |
410 | } | |
411 | ||
96d2ab48 | 412 | if (end_time && !timed_out) |
90d6e24a AV |
413 | slack = estimate_accuracy(end_time); |
414 | ||
1da177e4 LT |
415 | retval = 0; |
416 | for (;;) { | |
417 | unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp; | |
418 | ||
1da177e4 LT |
419 | inp = fds->in; outp = fds->out; exp = fds->ex; |
420 | rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex; | |
421 | ||
422 | for (i = 0; i < n; ++rinp, ++routp, ++rexp) { | |
423 | unsigned long in, out, ex, all_bits, bit = 1, mask, j; | |
424 | unsigned long res_in = 0, res_out = 0, res_ex = 0; | |
99ac48f5 | 425 | const struct file_operations *f_op = NULL; |
1da177e4 LT |
426 | struct file *file = NULL; |
427 | ||
428 | in = *inp++; out = *outp++; ex = *exp++; | |
429 | all_bits = in | out | ex; | |
430 | if (all_bits == 0) { | |
431 | i += __NFDBITS; | |
432 | continue; | |
433 | } | |
434 | ||
435 | for (j = 0; j < __NFDBITS; ++j, ++i, bit <<= 1) { | |
e4a1f129 | 436 | int fput_needed; |
1da177e4 LT |
437 | if (i >= n) |
438 | break; | |
439 | if (!(bit & all_bits)) | |
440 | continue; | |
e4a1f129 | 441 | file = fget_light(i, &fput_needed); |
1da177e4 LT |
442 | if (file) { |
443 | f_op = file->f_op; | |
444 | mask = DEFAULT_POLLMASK; | |
4938d7e0 ED |
445 | if (f_op && f_op->poll) { |
446 | wait_key_set(wait, in, out, bit); | |
447 | mask = (*f_op->poll)(file, wait); | |
448 | } | |
e4a1f129 | 449 | fput_light(file, fput_needed); |
1da177e4 LT |
450 | if ((mask & POLLIN_SET) && (in & bit)) { |
451 | res_in |= bit; | |
452 | retval++; | |
4938d7e0 | 453 | wait = NULL; |
1da177e4 LT |
454 | } |
455 | if ((mask & POLLOUT_SET) && (out & bit)) { | |
456 | res_out |= bit; | |
457 | retval++; | |
4938d7e0 | 458 | wait = NULL; |
1da177e4 LT |
459 | } |
460 | if ((mask & POLLEX_SET) && (ex & bit)) { | |
461 | res_ex |= bit; | |
462 | retval++; | |
4938d7e0 | 463 | wait = NULL; |
1da177e4 LT |
464 | } |
465 | } | |
1da177e4 LT |
466 | } |
467 | if (res_in) | |
468 | *rinp = res_in; | |
469 | if (res_out) | |
470 | *routp = res_out; | |
471 | if (res_ex) | |
472 | *rexp = res_ex; | |
55d85384 | 473 | cond_resched(); |
1da177e4 LT |
474 | } |
475 | wait = NULL; | |
8ff3e8e8 | 476 | if (retval || timed_out || signal_pending(current)) |
1da177e4 | 477 | break; |
f5264481 | 478 | if (table.error) { |
1da177e4 LT |
479 | retval = table.error; |
480 | break; | |
481 | } | |
9f72949f | 482 | |
8ff3e8e8 AV |
483 | /* |
484 | * If this is the first loop and we have a timeout | |
485 | * given, then we convert to ktime_t and set the to | |
486 | * pointer to the expiry value. | |
487 | */ | |
488 | if (end_time && !to) { | |
489 | expire = timespec_to_ktime(*end_time); | |
490 | to = &expire; | |
9f72949f | 491 | } |
8ff3e8e8 | 492 | |
5f820f64 TH |
493 | if (!poll_schedule_timeout(&table, TASK_INTERRUPTIBLE, |
494 | to, slack)) | |
8ff3e8e8 | 495 | timed_out = 1; |
1da177e4 | 496 | } |
1da177e4 LT |
497 | |
498 | poll_freewait(&table); | |
499 | ||
1da177e4 LT |
500 | return retval; |
501 | } | |
502 | ||
1da177e4 LT |
503 | /* |
504 | * We can actually return ERESTARTSYS instead of EINTR, but I'd | |
505 | * like to be certain this leads to no problems. So I return | |
506 | * EINTR just for safety. | |
507 | * | |
508 | * Update: ERESTARTSYS breaks at least the xview clock binary, so | |
509 | * I'm trying ERESTARTNOHAND which restart only when you want to. | |
510 | */ | |
511 | #define MAX_SELECT_SECONDS \ | |
512 | ((unsigned long) (MAX_SCHEDULE_TIMEOUT / HZ)-1) | |
513 | ||
a2dcb44c | 514 | int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp, |
8ff3e8e8 | 515 | fd_set __user *exp, struct timespec *end_time) |
1da177e4 LT |
516 | { |
517 | fd_set_bits fds; | |
29ff2db5 | 518 | void *bits; |
bbea9f69 | 519 | int ret, max_fds; |
b04eb6aa | 520 | unsigned int size; |
badf1662 | 521 | struct fdtable *fdt; |
70674f95 | 522 | /* Allocate small arguments on the stack to save memory and be faster */ |
30c14e40 | 523 | long stack_fds[SELECT_STACK_ALLOC/sizeof(long)]; |
1da177e4 | 524 | |
1da177e4 LT |
525 | ret = -EINVAL; |
526 | if (n < 0) | |
527 | goto out_nofds; | |
528 | ||
bbea9f69 | 529 | /* max_fds can increase, so grab it once to avoid race */ |
b835996f | 530 | rcu_read_lock(); |
badf1662 | 531 | fdt = files_fdtable(current->files); |
bbea9f69 | 532 | max_fds = fdt->max_fds; |
b835996f | 533 | rcu_read_unlock(); |
bbea9f69 VL |
534 | if (n > max_fds) |
535 | n = max_fds; | |
1da177e4 LT |
536 | |
537 | /* | |
538 | * We need 6 bitmaps (in/out/ex for both incoming and outgoing), | |
539 | * since we used fdset we need to allocate memory in units of | |
540 | * long-words. | |
541 | */ | |
1da177e4 | 542 | size = FDS_BYTES(n); |
b04eb6aa MBJ |
543 | bits = stack_fds; |
544 | if (size > sizeof(stack_fds) / 6) { | |
545 | /* Not enough space in on-stack array; must use kmalloc */ | |
546 | ret = -ENOMEM; | |
70674f95 | 547 | bits = kmalloc(6 * size, GFP_KERNEL); |
b04eb6aa MBJ |
548 | if (!bits) |
549 | goto out_nofds; | |
550 | } | |
29ff2db5 AM |
551 | fds.in = bits; |
552 | fds.out = bits + size; | |
553 | fds.ex = bits + 2*size; | |
554 | fds.res_in = bits + 3*size; | |
555 | fds.res_out = bits + 4*size; | |
556 | fds.res_ex = bits + 5*size; | |
1da177e4 LT |
557 | |
558 | if ((ret = get_fd_set(n, inp, fds.in)) || | |
559 | (ret = get_fd_set(n, outp, fds.out)) || | |
560 | (ret = get_fd_set(n, exp, fds.ex))) | |
561 | goto out; | |
562 | zero_fd_set(n, fds.res_in); | |
563 | zero_fd_set(n, fds.res_out); | |
564 | zero_fd_set(n, fds.res_ex); | |
565 | ||
8ff3e8e8 | 566 | ret = do_select(n, &fds, end_time); |
1da177e4 LT |
567 | |
568 | if (ret < 0) | |
569 | goto out; | |
570 | if (!ret) { | |
571 | ret = -ERESTARTNOHAND; | |
572 | if (signal_pending(current)) | |
573 | goto out; | |
574 | ret = 0; | |
575 | } | |
576 | ||
577 | if (set_fd_set(n, inp, fds.res_in) || | |
578 | set_fd_set(n, outp, fds.res_out) || | |
579 | set_fd_set(n, exp, fds.res_ex)) | |
580 | ret = -EFAULT; | |
581 | ||
582 | out: | |
70674f95 AK |
583 | if (bits != stack_fds) |
584 | kfree(bits); | |
1da177e4 LT |
585 | out_nofds: |
586 | return ret; | |
587 | } | |
588 | ||
5a8a82b1 HC |
589 | SYSCALL_DEFINE5(select, int, n, fd_set __user *, inp, fd_set __user *, outp, |
590 | fd_set __user *, exp, struct timeval __user *, tvp) | |
9f72949f | 591 | { |
8ff3e8e8 | 592 | struct timespec end_time, *to = NULL; |
9f72949f DW |
593 | struct timeval tv; |
594 | int ret; | |
595 | ||
596 | if (tvp) { | |
597 | if (copy_from_user(&tv, tvp, sizeof(tv))) | |
598 | return -EFAULT; | |
599 | ||
8ff3e8e8 | 600 | to = &end_time; |
4d36a9e6 AV |
601 | if (poll_select_set_timeout(to, |
602 | tv.tv_sec + (tv.tv_usec / USEC_PER_SEC), | |
603 | (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC)) | |
9f72949f | 604 | return -EINVAL; |
9f72949f DW |
605 | } |
606 | ||
8ff3e8e8 AV |
607 | ret = core_sys_select(n, inp, outp, exp, to); |
608 | ret = poll_select_copy_remaining(&end_time, tvp, 1, ret); | |
9f72949f DW |
609 | |
610 | return ret; | |
611 | } | |
612 | ||
f3de272b | 613 | #ifdef HAVE_SET_RESTORE_SIGMASK |
c9da9f21 HC |
614 | static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp, |
615 | fd_set __user *exp, struct timespec __user *tsp, | |
616 | const sigset_t __user *sigmask, size_t sigsetsize) | |
9f72949f | 617 | { |
9f72949f | 618 | sigset_t ksigmask, sigsaved; |
8ff3e8e8 | 619 | struct timespec ts, end_time, *to = NULL; |
9f72949f DW |
620 | int ret; |
621 | ||
622 | if (tsp) { | |
623 | if (copy_from_user(&ts, tsp, sizeof(ts))) | |
624 | return -EFAULT; | |
625 | ||
8ff3e8e8 AV |
626 | to = &end_time; |
627 | if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) | |
9f72949f | 628 | return -EINVAL; |
9f72949f DW |
629 | } |
630 | ||
631 | if (sigmask) { | |
632 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
633 | if (sigsetsize != sizeof(sigset_t)) | |
634 | return -EINVAL; | |
635 | if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask))) | |
636 | return -EFAULT; | |
637 | ||
638 | sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
639 | sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); | |
640 | } | |
641 | ||
62568510 | 642 | ret = core_sys_select(n, inp, outp, exp, to); |
8ff3e8e8 | 643 | ret = poll_select_copy_remaining(&end_time, tsp, 0, ret); |
9f72949f DW |
644 | |
645 | if (ret == -ERESTARTNOHAND) { | |
646 | /* | |
647 | * Don't restore the signal mask yet. Let do_signal() deliver | |
648 | * the signal on the way back to userspace, before the signal | |
649 | * mask is restored. | |
650 | */ | |
651 | if (sigmask) { | |
652 | memcpy(¤t->saved_sigmask, &sigsaved, | |
653 | sizeof(sigsaved)); | |
4e4c22c7 | 654 | set_restore_sigmask(); |
9f72949f DW |
655 | } |
656 | } else if (sigmask) | |
657 | sigprocmask(SIG_SETMASK, &sigsaved, NULL); | |
658 | ||
659 | return ret; | |
660 | } | |
661 | ||
662 | /* | |
663 | * Most architectures can't handle 7-argument syscalls. So we provide a | |
664 | * 6-argument version where the sixth argument is a pointer to a structure | |
665 | * which has a pointer to the sigset_t itself followed by a size_t containing | |
666 | * the sigset size. | |
667 | */ | |
d4e82042 HC |
668 | SYSCALL_DEFINE6(pselect6, int, n, fd_set __user *, inp, fd_set __user *, outp, |
669 | fd_set __user *, exp, struct timespec __user *, tsp, | |
670 | void __user *, sig) | |
9f72949f DW |
671 | { |
672 | size_t sigsetsize = 0; | |
673 | sigset_t __user *up = NULL; | |
674 | ||
675 | if (sig) { | |
676 | if (!access_ok(VERIFY_READ, sig, sizeof(void *)+sizeof(size_t)) | |
e110ab94 | 677 | || __get_user(up, (sigset_t __user * __user *)sig) |
9f72949f | 678 | || __get_user(sigsetsize, |
e110ab94 | 679 | (size_t __user *)(sig+sizeof(void *)))) |
9f72949f DW |
680 | return -EFAULT; |
681 | } | |
682 | ||
c9da9f21 | 683 | return do_pselect(n, inp, outp, exp, tsp, up, sigsetsize); |
9f72949f | 684 | } |
f3de272b | 685 | #endif /* HAVE_SET_RESTORE_SIGMASK */ |
9f72949f | 686 | |
1da177e4 LT |
687 | struct poll_list { |
688 | struct poll_list *next; | |
689 | int len; | |
690 | struct pollfd entries[0]; | |
691 | }; | |
692 | ||
693 | #define POLLFD_PER_PAGE ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd)) | |
694 | ||
4a4b69f7 VL |
695 | /* |
696 | * Fish for pollable events on the pollfd->fd file descriptor. We're only | |
697 | * interested in events matching the pollfd->events mask, and the result | |
698 | * matching that mask is both recorded in pollfd->revents and returned. The | |
699 | * pwait poll_table will be used by the fd-provided poll handler for waiting, | |
700 | * if non-NULL. | |
701 | */ | |
702 | static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait) | |
1da177e4 | 703 | { |
4a4b69f7 VL |
704 | unsigned int mask; |
705 | int fd; | |
706 | ||
707 | mask = 0; | |
708 | fd = pollfd->fd; | |
709 | if (fd >= 0) { | |
710 | int fput_needed; | |
711 | struct file * file; | |
712 | ||
713 | file = fget_light(fd, &fput_needed); | |
714 | mask = POLLNVAL; | |
715 | if (file != NULL) { | |
716 | mask = DEFAULT_POLLMASK; | |
4938d7e0 ED |
717 | if (file->f_op && file->f_op->poll) { |
718 | if (pwait) | |
719 | pwait->key = pollfd->events | | |
720 | POLLERR | POLLHUP; | |
4a4b69f7 | 721 | mask = file->f_op->poll(file, pwait); |
4938d7e0 | 722 | } |
4a4b69f7 VL |
723 | /* Mask out unneeded events. */ |
724 | mask &= pollfd->events | POLLERR | POLLHUP; | |
725 | fput_light(file, fput_needed); | |
1da177e4 | 726 | } |
1da177e4 | 727 | } |
4a4b69f7 VL |
728 | pollfd->revents = mask; |
729 | ||
730 | return mask; | |
1da177e4 LT |
731 | } |
732 | ||
733 | static int do_poll(unsigned int nfds, struct poll_list *list, | |
8ff3e8e8 | 734 | struct poll_wqueues *wait, struct timespec *end_time) |
1da177e4 | 735 | { |
1da177e4 | 736 | poll_table* pt = &wait->pt; |
8ff3e8e8 AV |
737 | ktime_t expire, *to = NULL; |
738 | int timed_out = 0, count = 0; | |
90d6e24a | 739 | unsigned long slack = 0; |
1da177e4 | 740 | |
9f72949f | 741 | /* Optimise the no-wait case */ |
8ff3e8e8 | 742 | if (end_time && !end_time->tv_sec && !end_time->tv_nsec) { |
1da177e4 | 743 | pt = NULL; |
8ff3e8e8 AV |
744 | timed_out = 1; |
745 | } | |
9bf084f7 | 746 | |
96d2ab48 | 747 | if (end_time && !timed_out) |
90d6e24a AV |
748 | slack = estimate_accuracy(end_time); |
749 | ||
1da177e4 LT |
750 | for (;;) { |
751 | struct poll_list *walk; | |
9f72949f | 752 | |
4a4b69f7 VL |
753 | for (walk = list; walk != NULL; walk = walk->next) { |
754 | struct pollfd * pfd, * pfd_end; | |
755 | ||
756 | pfd = walk->entries; | |
757 | pfd_end = pfd + walk->len; | |
758 | for (; pfd != pfd_end; pfd++) { | |
759 | /* | |
760 | * Fish for events. If we found one, record it | |
761 | * and kill the poll_table, so we don't | |
762 | * needlessly register any other waiters after | |
763 | * this. They'll get immediately deregistered | |
764 | * when we break out and return. | |
765 | */ | |
766 | if (do_pollfd(pfd, pt)) { | |
767 | count++; | |
768 | pt = NULL; | |
769 | } | |
770 | } | |
1da177e4 | 771 | } |
4a4b69f7 VL |
772 | /* |
773 | * All waiters have already been registered, so don't provide | |
774 | * a poll_table to them on the next loop iteration. | |
775 | */ | |
1da177e4 | 776 | pt = NULL; |
9bf084f7 ON |
777 | if (!count) { |
778 | count = wait->error; | |
779 | if (signal_pending(current)) | |
780 | count = -EINTR; | |
781 | } | |
8ff3e8e8 | 782 | if (count || timed_out) |
1da177e4 | 783 | break; |
9f72949f | 784 | |
8ff3e8e8 AV |
785 | /* |
786 | * If this is the first loop and we have a timeout | |
787 | * given, then we convert to ktime_t and set the to | |
788 | * pointer to the expiry value. | |
789 | */ | |
790 | if (end_time && !to) { | |
791 | expire = timespec_to_ktime(*end_time); | |
792 | to = &expire; | |
9f72949f DW |
793 | } |
794 | ||
5f820f64 | 795 | if (!poll_schedule_timeout(wait, TASK_INTERRUPTIBLE, to, slack)) |
8ff3e8e8 | 796 | timed_out = 1; |
1da177e4 | 797 | } |
1da177e4 LT |
798 | return count; |
799 | } | |
800 | ||
70674f95 AK |
801 | #define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \ |
802 | sizeof(struct pollfd)) | |
803 | ||
8ff3e8e8 AV |
804 | int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds, |
805 | struct timespec *end_time) | |
1da177e4 LT |
806 | { |
807 | struct poll_wqueues table; | |
252e5725 | 808 | int err = -EFAULT, fdcount, len, size; |
30c14e40 JS |
809 | /* Allocate small arguments on the stack to save memory and be |
810 | faster - use long to make sure the buffer is aligned properly | |
811 | on 64 bit archs to avoid unaligned access */ | |
812 | long stack_pps[POLL_STACK_ALLOC/sizeof(long)]; | |
252e5725 ON |
813 | struct poll_list *const head = (struct poll_list *)stack_pps; |
814 | struct poll_list *walk = head; | |
815 | unsigned long todo = nfds; | |
1da177e4 | 816 | |
4e6fd33b | 817 | if (nfds > current->signal->rlim[RLIMIT_NOFILE].rlim_cur) |
1da177e4 LT |
818 | return -EINVAL; |
819 | ||
252e5725 ON |
820 | len = min_t(unsigned int, nfds, N_STACK_PPS); |
821 | for (;;) { | |
822 | walk->next = NULL; | |
823 | walk->len = len; | |
824 | if (!len) | |
825 | break; | |
1da177e4 | 826 | |
252e5725 ON |
827 | if (copy_from_user(walk->entries, ufds + nfds-todo, |
828 | sizeof(struct pollfd) * walk->len)) | |
829 | goto out_fds; | |
830 | ||
831 | todo -= walk->len; | |
832 | if (!todo) | |
833 | break; | |
1da177e4 | 834 | |
252e5725 ON |
835 | len = min(todo, POLLFD_PER_PAGE); |
836 | size = sizeof(struct poll_list) + sizeof(struct pollfd) * len; | |
837 | walk = walk->next = kmalloc(size, GFP_KERNEL); | |
838 | if (!walk) { | |
839 | err = -ENOMEM; | |
1da177e4 LT |
840 | goto out_fds; |
841 | } | |
1da177e4 | 842 | } |
9f72949f | 843 | |
252e5725 | 844 | poll_initwait(&table); |
8ff3e8e8 | 845 | fdcount = do_poll(nfds, head, &table, end_time); |
252e5725 | 846 | poll_freewait(&table); |
1da177e4 | 847 | |
252e5725 | 848 | for (walk = head; walk; walk = walk->next) { |
1da177e4 LT |
849 | struct pollfd *fds = walk->entries; |
850 | int j; | |
851 | ||
252e5725 ON |
852 | for (j = 0; j < walk->len; j++, ufds++) |
853 | if (__put_user(fds[j].revents, &ufds->revents)) | |
1da177e4 | 854 | goto out_fds; |
1da177e4 | 855 | } |
252e5725 | 856 | |
1da177e4 | 857 | err = fdcount; |
1da177e4 | 858 | out_fds: |
252e5725 ON |
859 | walk = head->next; |
860 | while (walk) { | |
861 | struct poll_list *pos = walk; | |
862 | walk = walk->next; | |
863 | kfree(pos); | |
1da177e4 | 864 | } |
252e5725 | 865 | |
1da177e4 LT |
866 | return err; |
867 | } | |
9f72949f | 868 | |
3075d9da CW |
869 | static long do_restart_poll(struct restart_block *restart_block) |
870 | { | |
8ff3e8e8 AV |
871 | struct pollfd __user *ufds = restart_block->poll.ufds; |
872 | int nfds = restart_block->poll.nfds; | |
873 | struct timespec *to = NULL, end_time; | |
3075d9da CW |
874 | int ret; |
875 | ||
8ff3e8e8 AV |
876 | if (restart_block->poll.has_timeout) { |
877 | end_time.tv_sec = restart_block->poll.tv_sec; | |
878 | end_time.tv_nsec = restart_block->poll.tv_nsec; | |
879 | to = &end_time; | |
880 | } | |
881 | ||
882 | ret = do_sys_poll(ufds, nfds, to); | |
883 | ||
3075d9da CW |
884 | if (ret == -EINTR) { |
885 | restart_block->fn = do_restart_poll; | |
3075d9da CW |
886 | ret = -ERESTART_RESTARTBLOCK; |
887 | } | |
888 | return ret; | |
889 | } | |
890 | ||
5a8a82b1 HC |
891 | SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds, |
892 | long, timeout_msecs) | |
9f72949f | 893 | { |
8ff3e8e8 | 894 | struct timespec end_time, *to = NULL; |
3075d9da | 895 | int ret; |
9f72949f | 896 | |
8ff3e8e8 AV |
897 | if (timeout_msecs >= 0) { |
898 | to = &end_time; | |
899 | poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC, | |
900 | NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC)); | |
9f72949f DW |
901 | } |
902 | ||
8ff3e8e8 AV |
903 | ret = do_sys_poll(ufds, nfds, to); |
904 | ||
3075d9da CW |
905 | if (ret == -EINTR) { |
906 | struct restart_block *restart_block; | |
8ff3e8e8 | 907 | |
3075d9da CW |
908 | restart_block = ¤t_thread_info()->restart_block; |
909 | restart_block->fn = do_restart_poll; | |
8ff3e8e8 AV |
910 | restart_block->poll.ufds = ufds; |
911 | restart_block->poll.nfds = nfds; | |
912 | ||
913 | if (timeout_msecs >= 0) { | |
914 | restart_block->poll.tv_sec = end_time.tv_sec; | |
915 | restart_block->poll.tv_nsec = end_time.tv_nsec; | |
916 | restart_block->poll.has_timeout = 1; | |
917 | } else | |
918 | restart_block->poll.has_timeout = 0; | |
919 | ||
3075d9da CW |
920 | ret = -ERESTART_RESTARTBLOCK; |
921 | } | |
922 | return ret; | |
9f72949f DW |
923 | } |
924 | ||
f3de272b | 925 | #ifdef HAVE_SET_RESTORE_SIGMASK |
d4e82042 HC |
926 | SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds, |
927 | struct timespec __user *, tsp, const sigset_t __user *, sigmask, | |
928 | size_t, sigsetsize) | |
9f72949f DW |
929 | { |
930 | sigset_t ksigmask, sigsaved; | |
8ff3e8e8 | 931 | struct timespec ts, end_time, *to = NULL; |
9f72949f DW |
932 | int ret; |
933 | ||
934 | if (tsp) { | |
935 | if (copy_from_user(&ts, tsp, sizeof(ts))) | |
936 | return -EFAULT; | |
937 | ||
8ff3e8e8 AV |
938 | to = &end_time; |
939 | if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) | |
940 | return -EINVAL; | |
9f72949f DW |
941 | } |
942 | ||
943 | if (sigmask) { | |
944 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
945 | if (sigsetsize != sizeof(sigset_t)) | |
946 | return -EINVAL; | |
947 | if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask))) | |
948 | return -EFAULT; | |
949 | ||
950 | sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
951 | sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); | |
952 | } | |
953 | ||
8ff3e8e8 | 954 | ret = do_sys_poll(ufds, nfds, to); |
9f72949f DW |
955 | |
956 | /* We can restart this syscall, usually */ | |
957 | if (ret == -EINTR) { | |
958 | /* | |
959 | * Don't restore the signal mask yet. Let do_signal() deliver | |
960 | * the signal on the way back to userspace, before the signal | |
961 | * mask is restored. | |
962 | */ | |
963 | if (sigmask) { | |
964 | memcpy(¤t->saved_sigmask, &sigsaved, | |
965 | sizeof(sigsaved)); | |
4e4c22c7 | 966 | set_restore_sigmask(); |
9f72949f DW |
967 | } |
968 | ret = -ERESTARTNOHAND; | |
969 | } else if (sigmask) | |
970 | sigprocmask(SIG_SETMASK, &sigsaved, NULL); | |
971 | ||
8ff3e8e8 | 972 | ret = poll_select_copy_remaining(&end_time, tsp, 0, ret); |
9f72949f DW |
973 | |
974 | return ret; | |
975 | } | |
f3de272b | 976 | #endif /* HAVE_SET_RESTORE_SIGMASK */ |