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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> |
a99bbaf5 | 18 | #include <linux/sched.h> |
1da177e4 | 19 | #include <linux/syscalls.h> |
630d9c47 | 20 | #include <linux/export.h> |
1da177e4 | 21 | #include <linux/slab.h> |
1da177e4 LT |
22 | #include <linux/poll.h> |
23 | #include <linux/personality.h> /* for STICKY_TIMEOUTS */ | |
24 | #include <linux/file.h> | |
9f3acc31 | 25 | #include <linux/fdtable.h> |
1da177e4 | 26 | #include <linux/fs.h> |
b835996f | 27 | #include <linux/rcupdate.h> |
8ff3e8e8 | 28 | #include <linux/hrtimer.h> |
8bd75c77 | 29 | #include <linux/sched/rt.h> |
2d48d67f | 30 | #include <net/ll_poll.h> |
1da177e4 LT |
31 | |
32 | #include <asm/uaccess.h> | |
33 | ||
90d6e24a AV |
34 | |
35 | /* | |
36 | * Estimate expected accuracy in ns from a timeval. | |
37 | * | |
38 | * After quite a bit of churning around, we've settled on | |
39 | * a simple thing of taking 0.1% of the timeout as the | |
40 | * slack, with a cap of 100 msec. | |
41 | * "nice" tasks get a 0.5% slack instead. | |
42 | * | |
43 | * Consider this comment an open invitation to come up with even | |
44 | * better solutions.. | |
45 | */ | |
46 | ||
5ae87e79 GK |
47 | #define MAX_SLACK (100 * NSEC_PER_MSEC) |
48 | ||
96d2ab48 | 49 | static long __estimate_accuracy(struct timespec *tv) |
90d6e24a | 50 | { |
96d2ab48 | 51 | long slack; |
90d6e24a AV |
52 | int divfactor = 1000; |
53 | ||
5ae87e79 GK |
54 | if (tv->tv_sec < 0) |
55 | return 0; | |
56 | ||
4ce105d3 | 57 | if (task_nice(current) > 0) |
90d6e24a AV |
58 | divfactor = divfactor / 5; |
59 | ||
5ae87e79 GK |
60 | if (tv->tv_sec > MAX_SLACK / (NSEC_PER_SEC/divfactor)) |
61 | return MAX_SLACK; | |
62 | ||
90d6e24a AV |
63 | slack = tv->tv_nsec / divfactor; |
64 | slack += tv->tv_sec * (NSEC_PER_SEC/divfactor); | |
65 | ||
5ae87e79 GK |
66 | if (slack > MAX_SLACK) |
67 | return MAX_SLACK; | |
96d2ab48 | 68 | |
90d6e24a AV |
69 | return slack; |
70 | } | |
71 | ||
95aac7b1 | 72 | long select_estimate_accuracy(struct timespec *tv) |
90d6e24a AV |
73 | { |
74 | unsigned long ret; | |
75 | struct timespec now; | |
76 | ||
77 | /* | |
78 | * Realtime tasks get a slack of 0 for obvious reasons. | |
79 | */ | |
80 | ||
4ce105d3 | 81 | if (rt_task(current)) |
90d6e24a AV |
82 | return 0; |
83 | ||
84 | ktime_get_ts(&now); | |
85 | now = timespec_sub(*tv, now); | |
86 | ret = __estimate_accuracy(&now); | |
87 | if (ret < current->timer_slack_ns) | |
88 | return current->timer_slack_ns; | |
89 | return ret; | |
90 | } | |
91 | ||
92 | ||
93 | ||
1da177e4 LT |
94 | struct poll_table_page { |
95 | struct poll_table_page * next; | |
96 | struct poll_table_entry * entry; | |
97 | struct poll_table_entry entries[0]; | |
98 | }; | |
99 | ||
100 | #define POLL_TABLE_FULL(table) \ | |
101 | ((unsigned long)((table)->entry+1) > PAGE_SIZE + (unsigned long)(table)) | |
102 | ||
103 | /* | |
104 | * Ok, Peter made a complicated, but straightforward multiple_wait() function. | |
105 | * I have rewritten this, taking some shortcuts: This code may not be easy to | |
106 | * follow, but it should be free of race-conditions, and it's practical. If you | |
107 | * understand what I'm doing here, then you understand how the linux | |
108 | * sleep/wakeup mechanism works. | |
109 | * | |
110 | * Two very simple procedures, poll_wait() and poll_freewait() make all the | |
111 | * work. poll_wait() is an inline-function defined in <linux/poll.h>, | |
112 | * as all select/poll functions have to call it to add an entry to the | |
113 | * poll table. | |
114 | */ | |
75c96f85 AB |
115 | static void __pollwait(struct file *filp, wait_queue_head_t *wait_address, |
116 | poll_table *p); | |
1da177e4 LT |
117 | |
118 | void poll_initwait(struct poll_wqueues *pwq) | |
119 | { | |
120 | init_poll_funcptr(&pwq->pt, __pollwait); | |
5f820f64 | 121 | pwq->polling_task = current; |
b2add73d | 122 | pwq->triggered = 0; |
1da177e4 LT |
123 | pwq->error = 0; |
124 | pwq->table = NULL; | |
70674f95 | 125 | pwq->inline_index = 0; |
1da177e4 | 126 | } |
1da177e4 LT |
127 | EXPORT_SYMBOL(poll_initwait); |
128 | ||
70674f95 AK |
129 | static void free_poll_entry(struct poll_table_entry *entry) |
130 | { | |
ccf6780d | 131 | remove_wait_queue(entry->wait_address, &entry->wait); |
70674f95 AK |
132 | fput(entry->filp); |
133 | } | |
134 | ||
1da177e4 LT |
135 | void poll_freewait(struct poll_wqueues *pwq) |
136 | { | |
137 | struct poll_table_page * p = pwq->table; | |
70674f95 AK |
138 | int i; |
139 | for (i = 0; i < pwq->inline_index; i++) | |
140 | free_poll_entry(pwq->inline_entries + i); | |
1da177e4 LT |
141 | while (p) { |
142 | struct poll_table_entry * entry; | |
143 | struct poll_table_page *old; | |
144 | ||
145 | entry = p->entry; | |
146 | do { | |
147 | entry--; | |
70674f95 | 148 | free_poll_entry(entry); |
1da177e4 LT |
149 | } while (entry > p->entries); |
150 | old = p; | |
151 | p = p->next; | |
152 | free_page((unsigned long) old); | |
153 | } | |
154 | } | |
1da177e4 LT |
155 | EXPORT_SYMBOL(poll_freewait); |
156 | ||
5f820f64 | 157 | static struct poll_table_entry *poll_get_entry(struct poll_wqueues *p) |
1da177e4 | 158 | { |
1da177e4 LT |
159 | struct poll_table_page *table = p->table; |
160 | ||
70674f95 AK |
161 | if (p->inline_index < N_INLINE_POLL_ENTRIES) |
162 | return p->inline_entries + p->inline_index++; | |
163 | ||
1da177e4 LT |
164 | if (!table || POLL_TABLE_FULL(table)) { |
165 | struct poll_table_page *new_table; | |
166 | ||
167 | new_table = (struct poll_table_page *) __get_free_page(GFP_KERNEL); | |
168 | if (!new_table) { | |
169 | p->error = -ENOMEM; | |
70674f95 | 170 | return NULL; |
1da177e4 LT |
171 | } |
172 | new_table->entry = new_table->entries; | |
173 | new_table->next = table; | |
174 | p->table = new_table; | |
175 | table = new_table; | |
176 | } | |
177 | ||
70674f95 AK |
178 | return table->entry++; |
179 | } | |
180 | ||
4938d7e0 | 181 | static int __pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key) |
5f820f64 TH |
182 | { |
183 | struct poll_wqueues *pwq = wait->private; | |
184 | DECLARE_WAITQUEUE(dummy_wait, pwq->polling_task); | |
185 | ||
186 | /* | |
187 | * Although this function is called under waitqueue lock, LOCK | |
188 | * doesn't imply write barrier and the users expect write | |
189 | * barrier semantics on wakeup functions. The following | |
190 | * smp_wmb() is equivalent to smp_wmb() in try_to_wake_up() | |
191 | * and is paired with set_mb() in poll_schedule_timeout. | |
192 | */ | |
193 | smp_wmb(); | |
194 | pwq->triggered = 1; | |
195 | ||
196 | /* | |
197 | * Perform the default wake up operation using a dummy | |
198 | * waitqueue. | |
199 | * | |
200 | * TODO: This is hacky but there currently is no interface to | |
201 | * pass in @sync. @sync is scheduled to be removed and once | |
202 | * that happens, wake_up_process() can be used directly. | |
203 | */ | |
204 | return default_wake_function(&dummy_wait, mode, sync, key); | |
205 | } | |
206 | ||
4938d7e0 ED |
207 | static int pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key) |
208 | { | |
209 | struct poll_table_entry *entry; | |
210 | ||
211 | entry = container_of(wait, struct poll_table_entry, wait); | |
212 | if (key && !((unsigned long)key & entry->key)) | |
213 | return 0; | |
214 | return __pollwake(wait, mode, sync, key); | |
215 | } | |
216 | ||
70674f95 AK |
217 | /* Add a new entry */ |
218 | static void __pollwait(struct file *filp, wait_queue_head_t *wait_address, | |
219 | poll_table *p) | |
220 | { | |
5f820f64 TH |
221 | struct poll_wqueues *pwq = container_of(p, struct poll_wqueues, pt); |
222 | struct poll_table_entry *entry = poll_get_entry(pwq); | |
70674f95 AK |
223 | if (!entry) |
224 | return; | |
cb0942b8 | 225 | entry->filp = get_file(filp); |
70674f95 | 226 | entry->wait_address = wait_address; |
626cf236 | 227 | entry->key = p->_key; |
5f820f64 TH |
228 | init_waitqueue_func_entry(&entry->wait, pollwake); |
229 | entry->wait.private = pwq; | |
ccf6780d | 230 | add_wait_queue(wait_address, &entry->wait); |
1da177e4 LT |
231 | } |
232 | ||
5f820f64 TH |
233 | int poll_schedule_timeout(struct poll_wqueues *pwq, int state, |
234 | ktime_t *expires, unsigned long slack) | |
235 | { | |
236 | int rc = -EINTR; | |
237 | ||
238 | set_current_state(state); | |
239 | if (!pwq->triggered) | |
240 | rc = schedule_hrtimeout_range(expires, slack, HRTIMER_MODE_ABS); | |
241 | __set_current_state(TASK_RUNNING); | |
242 | ||
243 | /* | |
244 | * Prepare for the next iteration. | |
245 | * | |
246 | * The following set_mb() serves two purposes. First, it's | |
247 | * the counterpart rmb of the wmb in pollwake() such that data | |
248 | * written before wake up is always visible after wake up. | |
249 | * Second, the full barrier guarantees that triggered clearing | |
250 | * doesn't pass event check of the next iteration. Note that | |
251 | * this problem doesn't exist for the first iteration as | |
252 | * add_wait_queue() has full barrier semantics. | |
253 | */ | |
254 | set_mb(pwq->triggered, 0); | |
255 | ||
256 | return rc; | |
257 | } | |
258 | EXPORT_SYMBOL(poll_schedule_timeout); | |
259 | ||
b773ad40 TG |
260 | /** |
261 | * poll_select_set_timeout - helper function to setup the timeout value | |
262 | * @to: pointer to timespec variable for the final timeout | |
263 | * @sec: seconds (from user space) | |
264 | * @nsec: nanoseconds (from user space) | |
265 | * | |
266 | * Note, we do not use a timespec for the user space value here, That | |
267 | * way we can use the function for timeval and compat interfaces as well. | |
268 | * | |
269 | * Returns -EINVAL if sec/nsec are not normalized. Otherwise 0. | |
270 | */ | |
271 | int poll_select_set_timeout(struct timespec *to, long sec, long nsec) | |
272 | { | |
273 | struct timespec ts = {.tv_sec = sec, .tv_nsec = nsec}; | |
274 | ||
275 | if (!timespec_valid(&ts)) | |
276 | return -EINVAL; | |
277 | ||
278 | /* Optimize for the zero timeout value here */ | |
279 | if (!sec && !nsec) { | |
280 | to->tv_sec = to->tv_nsec = 0; | |
281 | } else { | |
282 | ktime_get_ts(to); | |
283 | *to = timespec_add_safe(*to, ts); | |
284 | } | |
285 | return 0; | |
286 | } | |
287 | ||
288 | static int poll_select_copy_remaining(struct timespec *end_time, void __user *p, | |
289 | int timeval, int ret) | |
290 | { | |
291 | struct timespec rts; | |
292 | struct timeval rtv; | |
293 | ||
294 | if (!p) | |
295 | return ret; | |
296 | ||
297 | if (current->personality & STICKY_TIMEOUTS) | |
298 | goto sticky; | |
299 | ||
300 | /* No update for zero timeout */ | |
301 | if (!end_time->tv_sec && !end_time->tv_nsec) | |
302 | return ret; | |
303 | ||
304 | ktime_get_ts(&rts); | |
305 | rts = timespec_sub(*end_time, rts); | |
306 | if (rts.tv_sec < 0) | |
307 | rts.tv_sec = rts.tv_nsec = 0; | |
308 | ||
309 | if (timeval) { | |
65329bf4 VK |
310 | if (sizeof(rtv) > sizeof(rtv.tv_sec) + sizeof(rtv.tv_usec)) |
311 | memset(&rtv, 0, sizeof(rtv)); | |
b773ad40 TG |
312 | rtv.tv_sec = rts.tv_sec; |
313 | rtv.tv_usec = rts.tv_nsec / NSEC_PER_USEC; | |
314 | ||
315 | if (!copy_to_user(p, &rtv, sizeof(rtv))) | |
316 | return ret; | |
317 | ||
318 | } else if (!copy_to_user(p, &rts, sizeof(rts))) | |
319 | return ret; | |
320 | ||
321 | /* | |
322 | * If an application puts its timeval in read-only memory, we | |
323 | * don't want the Linux-specific update to the timeval to | |
324 | * cause a fault after the select has completed | |
325 | * successfully. However, because we're not updating the | |
326 | * timeval, we can't restart the system call. | |
327 | */ | |
328 | ||
329 | sticky: | |
330 | if (ret == -ERESTARTNOHAND) | |
331 | ret = -EINTR; | |
332 | return ret; | |
333 | } | |
334 | ||
1da177e4 LT |
335 | #define FDS_IN(fds, n) (fds->in + n) |
336 | #define FDS_OUT(fds, n) (fds->out + n) | |
337 | #define FDS_EX(fds, n) (fds->ex + n) | |
338 | ||
339 | #define BITS(fds, n) (*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n)) | |
340 | ||
341 | static int max_select_fd(unsigned long n, fd_set_bits *fds) | |
342 | { | |
343 | unsigned long *open_fds; | |
344 | unsigned long set; | |
345 | int max; | |
badf1662 | 346 | struct fdtable *fdt; |
1da177e4 LT |
347 | |
348 | /* handle last in-complete long-word first */ | |
8ded2bbc JB |
349 | set = ~(~0UL << (n & (BITS_PER_LONG-1))); |
350 | n /= BITS_PER_LONG; | |
badf1662 | 351 | fdt = files_fdtable(current->files); |
1fd36adc | 352 | open_fds = fdt->open_fds + n; |
1da177e4 LT |
353 | max = 0; |
354 | if (set) { | |
355 | set &= BITS(fds, n); | |
356 | if (set) { | |
357 | if (!(set & ~*open_fds)) | |
358 | goto get_max; | |
359 | return -EBADF; | |
360 | } | |
361 | } | |
362 | while (n) { | |
363 | open_fds--; | |
364 | n--; | |
365 | set = BITS(fds, n); | |
366 | if (!set) | |
367 | continue; | |
368 | if (set & ~*open_fds) | |
369 | return -EBADF; | |
370 | if (max) | |
371 | continue; | |
372 | get_max: | |
373 | do { | |
374 | max++; | |
375 | set >>= 1; | |
376 | } while (set); | |
8ded2bbc | 377 | max += n * BITS_PER_LONG; |
1da177e4 LT |
378 | } |
379 | ||
380 | return max; | |
381 | } | |
382 | ||
1da177e4 LT |
383 | #define POLLIN_SET (POLLRDNORM | POLLRDBAND | POLLIN | POLLHUP | POLLERR) |
384 | #define POLLOUT_SET (POLLWRBAND | POLLWRNORM | POLLOUT | POLLERR) | |
385 | #define POLLEX_SET (POLLPRI) | |
386 | ||
4938d7e0 | 387 | static inline void wait_key_set(poll_table *wait, unsigned long in, |
2d48d67f ET |
388 | unsigned long out, unsigned long bit, |
389 | unsigned int ll_flag) | |
4938d7e0 | 390 | { |
2d48d67f | 391 | wait->_key = POLLEX_SET | ll_flag; |
626cf236 HV |
392 | if (in & bit) |
393 | wait->_key |= POLLIN_SET; | |
394 | if (out & bit) | |
395 | wait->_key |= POLLOUT_SET; | |
4938d7e0 ED |
396 | } |
397 | ||
8ff3e8e8 | 398 | int do_select(int n, fd_set_bits *fds, struct timespec *end_time) |
1da177e4 | 399 | { |
8ff3e8e8 | 400 | ktime_t expire, *to = NULL; |
1da177e4 LT |
401 | struct poll_wqueues table; |
402 | poll_table *wait; | |
8ff3e8e8 | 403 | int retval, i, timed_out = 0; |
90d6e24a | 404 | unsigned long slack = 0; |
91e2fd33 | 405 | unsigned int ll_flag = ll_get_flag(); |
1bc2774d ET |
406 | u64 ll_start = ll_start_time(ll_flag); |
407 | u64 ll_time = ll_run_time(); | |
1da177e4 | 408 | |
b835996f | 409 | rcu_read_lock(); |
1da177e4 | 410 | retval = max_select_fd(n, fds); |
b835996f | 411 | rcu_read_unlock(); |
1da177e4 LT |
412 | |
413 | if (retval < 0) | |
414 | return retval; | |
415 | n = retval; | |
416 | ||
417 | poll_initwait(&table); | |
418 | wait = &table.pt; | |
8ff3e8e8 | 419 | if (end_time && !end_time->tv_sec && !end_time->tv_nsec) { |
626cf236 | 420 | wait->_qproc = NULL; |
8ff3e8e8 AV |
421 | timed_out = 1; |
422 | } | |
423 | ||
96d2ab48 | 424 | if (end_time && !timed_out) |
231f3d39 | 425 | slack = select_estimate_accuracy(end_time); |
90d6e24a | 426 | |
1da177e4 LT |
427 | retval = 0; |
428 | for (;;) { | |
429 | unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp; | |
2d48d67f | 430 | bool can_ll = false; |
1da177e4 | 431 | |
1da177e4 LT |
432 | inp = fds->in; outp = fds->out; exp = fds->ex; |
433 | rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex; | |
434 | ||
435 | for (i = 0; i < n; ++rinp, ++routp, ++rexp) { | |
436 | unsigned long in, out, ex, all_bits, bit = 1, mask, j; | |
437 | unsigned long res_in = 0, res_out = 0, res_ex = 0; | |
1da177e4 LT |
438 | |
439 | in = *inp++; out = *outp++; ex = *exp++; | |
440 | all_bits = in | out | ex; | |
441 | if (all_bits == 0) { | |
8ded2bbc | 442 | i += BITS_PER_LONG; |
1da177e4 LT |
443 | continue; |
444 | } | |
445 | ||
8ded2bbc | 446 | for (j = 0; j < BITS_PER_LONG; ++j, ++i, bit <<= 1) { |
2903ff01 | 447 | struct fd f; |
1da177e4 LT |
448 | if (i >= n) |
449 | break; | |
450 | if (!(bit & all_bits)) | |
451 | continue; | |
2903ff01 AV |
452 | f = fdget(i); |
453 | if (f.file) { | |
454 | const struct file_operations *f_op; | |
455 | f_op = f.file->f_op; | |
1da177e4 | 456 | mask = DEFAULT_POLLMASK; |
4938d7e0 | 457 | if (f_op && f_op->poll) { |
2d48d67f ET |
458 | wait_key_set(wait, in, out, |
459 | bit, ll_flag); | |
2903ff01 | 460 | mask = (*f_op->poll)(f.file, wait); |
4938d7e0 | 461 | } |
2903ff01 | 462 | fdput(f); |
1da177e4 LT |
463 | if ((mask & POLLIN_SET) && (in & bit)) { |
464 | res_in |= bit; | |
465 | retval++; | |
626cf236 | 466 | wait->_qproc = NULL; |
1da177e4 LT |
467 | } |
468 | if ((mask & POLLOUT_SET) && (out & bit)) { | |
469 | res_out |= bit; | |
470 | retval++; | |
626cf236 | 471 | wait->_qproc = NULL; |
1da177e4 LT |
472 | } |
473 | if ((mask & POLLEX_SET) && (ex & bit)) { | |
474 | res_ex |= bit; | |
475 | retval++; | |
626cf236 | 476 | wait->_qproc = NULL; |
1da177e4 | 477 | } |
2d48d67f ET |
478 | if (mask & POLL_LL) |
479 | can_ll = true; | |
480 | /* got something, stop busy polling */ | |
481 | if (retval) | |
482 | ll_flag = 0; | |
1da177e4 | 483 | } |
1da177e4 LT |
484 | } |
485 | if (res_in) | |
486 | *rinp = res_in; | |
487 | if (res_out) | |
488 | *routp = res_out; | |
489 | if (res_ex) | |
490 | *rexp = res_ex; | |
55d85384 | 491 | cond_resched(); |
1da177e4 | 492 | } |
626cf236 | 493 | wait->_qproc = NULL; |
8ff3e8e8 | 494 | if (retval || timed_out || signal_pending(current)) |
1da177e4 | 495 | break; |
f5264481 | 496 | if (table.error) { |
1da177e4 LT |
497 | retval = table.error; |
498 | break; | |
499 | } | |
9f72949f | 500 | |
91e2fd33 | 501 | /* only if on, have sockets with POLL_LL and not out of time */ |
1bc2774d | 502 | if (ll_flag && can_ll && can_poll_ll(ll_start, ll_time)) |
2d48d67f ET |
503 | continue; |
504 | ||
8ff3e8e8 AV |
505 | /* |
506 | * If this is the first loop and we have a timeout | |
507 | * given, then we convert to ktime_t and set the to | |
508 | * pointer to the expiry value. | |
509 | */ | |
510 | if (end_time && !to) { | |
511 | expire = timespec_to_ktime(*end_time); | |
512 | to = &expire; | |
9f72949f | 513 | } |
8ff3e8e8 | 514 | |
5f820f64 TH |
515 | if (!poll_schedule_timeout(&table, TASK_INTERRUPTIBLE, |
516 | to, slack)) | |
8ff3e8e8 | 517 | timed_out = 1; |
1da177e4 | 518 | } |
1da177e4 LT |
519 | |
520 | poll_freewait(&table); | |
521 | ||
1da177e4 LT |
522 | return retval; |
523 | } | |
524 | ||
1da177e4 LT |
525 | /* |
526 | * We can actually return ERESTARTSYS instead of EINTR, but I'd | |
527 | * like to be certain this leads to no problems. So I return | |
528 | * EINTR just for safety. | |
529 | * | |
530 | * Update: ERESTARTSYS breaks at least the xview clock binary, so | |
531 | * I'm trying ERESTARTNOHAND which restart only when you want to. | |
532 | */ | |
a2dcb44c | 533 | int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp, |
8ff3e8e8 | 534 | fd_set __user *exp, struct timespec *end_time) |
1da177e4 LT |
535 | { |
536 | fd_set_bits fds; | |
29ff2db5 | 537 | void *bits; |
bbea9f69 | 538 | int ret, max_fds; |
b04eb6aa | 539 | unsigned int size; |
badf1662 | 540 | struct fdtable *fdt; |
70674f95 | 541 | /* Allocate small arguments on the stack to save memory and be faster */ |
30c14e40 | 542 | long stack_fds[SELECT_STACK_ALLOC/sizeof(long)]; |
1da177e4 | 543 | |
1da177e4 LT |
544 | ret = -EINVAL; |
545 | if (n < 0) | |
546 | goto out_nofds; | |
547 | ||
bbea9f69 | 548 | /* max_fds can increase, so grab it once to avoid race */ |
b835996f | 549 | rcu_read_lock(); |
badf1662 | 550 | fdt = files_fdtable(current->files); |
bbea9f69 | 551 | max_fds = fdt->max_fds; |
b835996f | 552 | rcu_read_unlock(); |
bbea9f69 VL |
553 | if (n > max_fds) |
554 | n = max_fds; | |
1da177e4 LT |
555 | |
556 | /* | |
557 | * We need 6 bitmaps (in/out/ex for both incoming and outgoing), | |
558 | * since we used fdset we need to allocate memory in units of | |
559 | * long-words. | |
560 | */ | |
1da177e4 | 561 | size = FDS_BYTES(n); |
b04eb6aa MBJ |
562 | bits = stack_fds; |
563 | if (size > sizeof(stack_fds) / 6) { | |
564 | /* Not enough space in on-stack array; must use kmalloc */ | |
565 | ret = -ENOMEM; | |
70674f95 | 566 | bits = kmalloc(6 * size, GFP_KERNEL); |
b04eb6aa MBJ |
567 | if (!bits) |
568 | goto out_nofds; | |
569 | } | |
29ff2db5 AM |
570 | fds.in = bits; |
571 | fds.out = bits + size; | |
572 | fds.ex = bits + 2*size; | |
573 | fds.res_in = bits + 3*size; | |
574 | fds.res_out = bits + 4*size; | |
575 | fds.res_ex = bits + 5*size; | |
1da177e4 LT |
576 | |
577 | if ((ret = get_fd_set(n, inp, fds.in)) || | |
578 | (ret = get_fd_set(n, outp, fds.out)) || | |
579 | (ret = get_fd_set(n, exp, fds.ex))) | |
580 | goto out; | |
581 | zero_fd_set(n, fds.res_in); | |
582 | zero_fd_set(n, fds.res_out); | |
583 | zero_fd_set(n, fds.res_ex); | |
584 | ||
8ff3e8e8 | 585 | ret = do_select(n, &fds, end_time); |
1da177e4 LT |
586 | |
587 | if (ret < 0) | |
588 | goto out; | |
589 | if (!ret) { | |
590 | ret = -ERESTARTNOHAND; | |
591 | if (signal_pending(current)) | |
592 | goto out; | |
593 | ret = 0; | |
594 | } | |
595 | ||
596 | if (set_fd_set(n, inp, fds.res_in) || | |
597 | set_fd_set(n, outp, fds.res_out) || | |
598 | set_fd_set(n, exp, fds.res_ex)) | |
599 | ret = -EFAULT; | |
600 | ||
601 | out: | |
70674f95 AK |
602 | if (bits != stack_fds) |
603 | kfree(bits); | |
1da177e4 LT |
604 | out_nofds: |
605 | return ret; | |
606 | } | |
607 | ||
5a8a82b1 HC |
608 | SYSCALL_DEFINE5(select, int, n, fd_set __user *, inp, fd_set __user *, outp, |
609 | fd_set __user *, exp, struct timeval __user *, tvp) | |
9f72949f | 610 | { |
8ff3e8e8 | 611 | struct timespec end_time, *to = NULL; |
9f72949f DW |
612 | struct timeval tv; |
613 | int ret; | |
614 | ||
615 | if (tvp) { | |
616 | if (copy_from_user(&tv, tvp, sizeof(tv))) | |
617 | return -EFAULT; | |
618 | ||
8ff3e8e8 | 619 | to = &end_time; |
4d36a9e6 AV |
620 | if (poll_select_set_timeout(to, |
621 | tv.tv_sec + (tv.tv_usec / USEC_PER_SEC), | |
622 | (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC)) | |
9f72949f | 623 | return -EINVAL; |
9f72949f DW |
624 | } |
625 | ||
8ff3e8e8 AV |
626 | ret = core_sys_select(n, inp, outp, exp, to); |
627 | ret = poll_select_copy_remaining(&end_time, tvp, 1, ret); | |
9f72949f DW |
628 | |
629 | return ret; | |
630 | } | |
631 | ||
c9da9f21 HC |
632 | static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp, |
633 | fd_set __user *exp, struct timespec __user *tsp, | |
634 | const sigset_t __user *sigmask, size_t sigsetsize) | |
9f72949f | 635 | { |
9f72949f | 636 | sigset_t ksigmask, sigsaved; |
8ff3e8e8 | 637 | struct timespec ts, end_time, *to = NULL; |
9f72949f DW |
638 | int ret; |
639 | ||
640 | if (tsp) { | |
641 | if (copy_from_user(&ts, tsp, sizeof(ts))) | |
642 | return -EFAULT; | |
643 | ||
8ff3e8e8 AV |
644 | to = &end_time; |
645 | if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) | |
9f72949f | 646 | return -EINVAL; |
9f72949f DW |
647 | } |
648 | ||
649 | if (sigmask) { | |
650 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
651 | if (sigsetsize != sizeof(sigset_t)) | |
652 | return -EINVAL; | |
653 | if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask))) | |
654 | return -EFAULT; | |
655 | ||
656 | sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
657 | sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); | |
658 | } | |
659 | ||
62568510 | 660 | ret = core_sys_select(n, inp, outp, exp, to); |
8ff3e8e8 | 661 | ret = poll_select_copy_remaining(&end_time, tsp, 0, ret); |
9f72949f DW |
662 | |
663 | if (ret == -ERESTARTNOHAND) { | |
664 | /* | |
665 | * Don't restore the signal mask yet. Let do_signal() deliver | |
666 | * the signal on the way back to userspace, before the signal | |
667 | * mask is restored. | |
668 | */ | |
669 | if (sigmask) { | |
670 | memcpy(¤t->saved_sigmask, &sigsaved, | |
671 | sizeof(sigsaved)); | |
4e4c22c7 | 672 | set_restore_sigmask(); |
9f72949f DW |
673 | } |
674 | } else if (sigmask) | |
675 | sigprocmask(SIG_SETMASK, &sigsaved, NULL); | |
676 | ||
677 | return ret; | |
678 | } | |
679 | ||
680 | /* | |
681 | * Most architectures can't handle 7-argument syscalls. So we provide a | |
682 | * 6-argument version where the sixth argument is a pointer to a structure | |
683 | * which has a pointer to the sigset_t itself followed by a size_t containing | |
684 | * the sigset size. | |
685 | */ | |
d4e82042 HC |
686 | SYSCALL_DEFINE6(pselect6, int, n, fd_set __user *, inp, fd_set __user *, outp, |
687 | fd_set __user *, exp, struct timespec __user *, tsp, | |
688 | void __user *, sig) | |
9f72949f DW |
689 | { |
690 | size_t sigsetsize = 0; | |
691 | sigset_t __user *up = NULL; | |
692 | ||
693 | if (sig) { | |
694 | if (!access_ok(VERIFY_READ, sig, sizeof(void *)+sizeof(size_t)) | |
e110ab94 | 695 | || __get_user(up, (sigset_t __user * __user *)sig) |
9f72949f | 696 | || __get_user(sigsetsize, |
e110ab94 | 697 | (size_t __user *)(sig+sizeof(void *)))) |
9f72949f DW |
698 | return -EFAULT; |
699 | } | |
700 | ||
c9da9f21 | 701 | return do_pselect(n, inp, outp, exp, tsp, up, sigsetsize); |
9f72949f | 702 | } |
9f72949f | 703 | |
5d0e5283 CH |
704 | #ifdef __ARCH_WANT_SYS_OLD_SELECT |
705 | struct sel_arg_struct { | |
706 | unsigned long n; | |
707 | fd_set __user *inp, *outp, *exp; | |
708 | struct timeval __user *tvp; | |
709 | }; | |
710 | ||
711 | SYSCALL_DEFINE1(old_select, struct sel_arg_struct __user *, arg) | |
712 | { | |
713 | struct sel_arg_struct a; | |
714 | ||
715 | if (copy_from_user(&a, arg, sizeof(a))) | |
716 | return -EFAULT; | |
717 | return sys_select(a.n, a.inp, a.outp, a.exp, a.tvp); | |
718 | } | |
719 | #endif | |
720 | ||
1da177e4 LT |
721 | struct poll_list { |
722 | struct poll_list *next; | |
723 | int len; | |
724 | struct pollfd entries[0]; | |
725 | }; | |
726 | ||
727 | #define POLLFD_PER_PAGE ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd)) | |
728 | ||
4a4b69f7 VL |
729 | /* |
730 | * Fish for pollable events on the pollfd->fd file descriptor. We're only | |
731 | * interested in events matching the pollfd->events mask, and the result | |
732 | * matching that mask is both recorded in pollfd->revents and returned. The | |
733 | * pwait poll_table will be used by the fd-provided poll handler for waiting, | |
626cf236 | 734 | * if pwait->_qproc is non-NULL. |
4a4b69f7 | 735 | */ |
2d48d67f ET |
736 | static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait, |
737 | bool *can_ll, unsigned int ll_flag) | |
1da177e4 | 738 | { |
4a4b69f7 VL |
739 | unsigned int mask; |
740 | int fd; | |
741 | ||
742 | mask = 0; | |
743 | fd = pollfd->fd; | |
744 | if (fd >= 0) { | |
2903ff01 | 745 | struct fd f = fdget(fd); |
4a4b69f7 | 746 | mask = POLLNVAL; |
2903ff01 | 747 | if (f.file) { |
4a4b69f7 | 748 | mask = DEFAULT_POLLMASK; |
2903ff01 | 749 | if (f.file->f_op && f.file->f_op->poll) { |
626cf236 | 750 | pwait->_key = pollfd->events|POLLERR|POLLHUP; |
2d48d67f | 751 | pwait->_key |= ll_flag; |
2903ff01 | 752 | mask = f.file->f_op->poll(f.file, pwait); |
2d48d67f ET |
753 | if (mask & POLL_LL) |
754 | *can_ll = true; | |
4938d7e0 | 755 | } |
4a4b69f7 VL |
756 | /* Mask out unneeded events. */ |
757 | mask &= pollfd->events | POLLERR | POLLHUP; | |
2903ff01 | 758 | fdput(f); |
1da177e4 | 759 | } |
1da177e4 | 760 | } |
4a4b69f7 VL |
761 | pollfd->revents = mask; |
762 | ||
763 | return mask; | |
1da177e4 LT |
764 | } |
765 | ||
766 | static int do_poll(unsigned int nfds, struct poll_list *list, | |
8ff3e8e8 | 767 | struct poll_wqueues *wait, struct timespec *end_time) |
1da177e4 | 768 | { |
1da177e4 | 769 | poll_table* pt = &wait->pt; |
8ff3e8e8 AV |
770 | ktime_t expire, *to = NULL; |
771 | int timed_out = 0, count = 0; | |
90d6e24a | 772 | unsigned long slack = 0; |
91e2fd33 | 773 | unsigned int ll_flag = ll_get_flag(); |
1bc2774d ET |
774 | u64 ll_start = ll_start_time(ll_flag); |
775 | u64 ll_time = ll_run_time(); | |
1da177e4 | 776 | |
9f72949f | 777 | /* Optimise the no-wait case */ |
8ff3e8e8 | 778 | if (end_time && !end_time->tv_sec && !end_time->tv_nsec) { |
626cf236 | 779 | pt->_qproc = NULL; |
8ff3e8e8 AV |
780 | timed_out = 1; |
781 | } | |
9bf084f7 | 782 | |
96d2ab48 | 783 | if (end_time && !timed_out) |
231f3d39 | 784 | slack = select_estimate_accuracy(end_time); |
90d6e24a | 785 | |
1da177e4 LT |
786 | for (;;) { |
787 | struct poll_list *walk; | |
2d48d67f | 788 | bool can_ll = false; |
9f72949f | 789 | |
4a4b69f7 VL |
790 | for (walk = list; walk != NULL; walk = walk->next) { |
791 | struct pollfd * pfd, * pfd_end; | |
792 | ||
793 | pfd = walk->entries; | |
794 | pfd_end = pfd + walk->len; | |
795 | for (; pfd != pfd_end; pfd++) { | |
796 | /* | |
797 | * Fish for events. If we found one, record it | |
626cf236 | 798 | * and kill poll_table->_qproc, so we don't |
4a4b69f7 VL |
799 | * needlessly register any other waiters after |
800 | * this. They'll get immediately deregistered | |
801 | * when we break out and return. | |
802 | */ | |
2d48d67f | 803 | if (do_pollfd(pfd, pt, &can_ll, ll_flag)) { |
4a4b69f7 | 804 | count++; |
626cf236 | 805 | pt->_qproc = NULL; |
2d48d67f | 806 | ll_flag = 0; |
4a4b69f7 VL |
807 | } |
808 | } | |
1da177e4 | 809 | } |
4a4b69f7 VL |
810 | /* |
811 | * All waiters have already been registered, so don't provide | |
626cf236 | 812 | * a poll_table->_qproc to them on the next loop iteration. |
4a4b69f7 | 813 | */ |
626cf236 | 814 | pt->_qproc = NULL; |
9bf084f7 ON |
815 | if (!count) { |
816 | count = wait->error; | |
817 | if (signal_pending(current)) | |
818 | count = -EINTR; | |
819 | } | |
8ff3e8e8 | 820 | if (count || timed_out) |
1da177e4 | 821 | break; |
9f72949f | 822 | |
91e2fd33 | 823 | /* only if on, have sockets with POLL_LL and not out of time */ |
1bc2774d | 824 | if (ll_flag && can_ll && can_poll_ll(ll_start, ll_time)) |
2d48d67f | 825 | continue; |
91e2fd33 | 826 | |
8ff3e8e8 AV |
827 | /* |
828 | * If this is the first loop and we have a timeout | |
829 | * given, then we convert to ktime_t and set the to | |
830 | * pointer to the expiry value. | |
831 | */ | |
832 | if (end_time && !to) { | |
833 | expire = timespec_to_ktime(*end_time); | |
834 | to = &expire; | |
9f72949f DW |
835 | } |
836 | ||
5f820f64 | 837 | if (!poll_schedule_timeout(wait, TASK_INTERRUPTIBLE, to, slack)) |
8ff3e8e8 | 838 | timed_out = 1; |
1da177e4 | 839 | } |
1da177e4 LT |
840 | return count; |
841 | } | |
842 | ||
70674f95 AK |
843 | #define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \ |
844 | sizeof(struct pollfd)) | |
845 | ||
8ff3e8e8 AV |
846 | int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds, |
847 | struct timespec *end_time) | |
1da177e4 LT |
848 | { |
849 | struct poll_wqueues table; | |
252e5725 | 850 | int err = -EFAULT, fdcount, len, size; |
30c14e40 JS |
851 | /* Allocate small arguments on the stack to save memory and be |
852 | faster - use long to make sure the buffer is aligned properly | |
853 | on 64 bit archs to avoid unaligned access */ | |
854 | long stack_pps[POLL_STACK_ALLOC/sizeof(long)]; | |
252e5725 ON |
855 | struct poll_list *const head = (struct poll_list *)stack_pps; |
856 | struct poll_list *walk = head; | |
857 | unsigned long todo = nfds; | |
1da177e4 | 858 | |
d554ed89 | 859 | if (nfds > rlimit(RLIMIT_NOFILE)) |
1da177e4 LT |
860 | return -EINVAL; |
861 | ||
252e5725 ON |
862 | len = min_t(unsigned int, nfds, N_STACK_PPS); |
863 | for (;;) { | |
864 | walk->next = NULL; | |
865 | walk->len = len; | |
866 | if (!len) | |
867 | break; | |
1da177e4 | 868 | |
252e5725 ON |
869 | if (copy_from_user(walk->entries, ufds + nfds-todo, |
870 | sizeof(struct pollfd) * walk->len)) | |
871 | goto out_fds; | |
872 | ||
873 | todo -= walk->len; | |
874 | if (!todo) | |
875 | break; | |
1da177e4 | 876 | |
252e5725 ON |
877 | len = min(todo, POLLFD_PER_PAGE); |
878 | size = sizeof(struct poll_list) + sizeof(struct pollfd) * len; | |
879 | walk = walk->next = kmalloc(size, GFP_KERNEL); | |
880 | if (!walk) { | |
881 | err = -ENOMEM; | |
1da177e4 LT |
882 | goto out_fds; |
883 | } | |
1da177e4 | 884 | } |
9f72949f | 885 | |
252e5725 | 886 | poll_initwait(&table); |
8ff3e8e8 | 887 | fdcount = do_poll(nfds, head, &table, end_time); |
252e5725 | 888 | poll_freewait(&table); |
1da177e4 | 889 | |
252e5725 | 890 | for (walk = head; walk; walk = walk->next) { |
1da177e4 LT |
891 | struct pollfd *fds = walk->entries; |
892 | int j; | |
893 | ||
252e5725 ON |
894 | for (j = 0; j < walk->len; j++, ufds++) |
895 | if (__put_user(fds[j].revents, &ufds->revents)) | |
1da177e4 | 896 | goto out_fds; |
1da177e4 | 897 | } |
252e5725 | 898 | |
1da177e4 | 899 | err = fdcount; |
1da177e4 | 900 | out_fds: |
252e5725 ON |
901 | walk = head->next; |
902 | while (walk) { | |
903 | struct poll_list *pos = walk; | |
904 | walk = walk->next; | |
905 | kfree(pos); | |
1da177e4 | 906 | } |
252e5725 | 907 | |
1da177e4 LT |
908 | return err; |
909 | } | |
9f72949f | 910 | |
3075d9da CW |
911 | static long do_restart_poll(struct restart_block *restart_block) |
912 | { | |
8ff3e8e8 AV |
913 | struct pollfd __user *ufds = restart_block->poll.ufds; |
914 | int nfds = restart_block->poll.nfds; | |
915 | struct timespec *to = NULL, end_time; | |
3075d9da CW |
916 | int ret; |
917 | ||
8ff3e8e8 AV |
918 | if (restart_block->poll.has_timeout) { |
919 | end_time.tv_sec = restart_block->poll.tv_sec; | |
920 | end_time.tv_nsec = restart_block->poll.tv_nsec; | |
921 | to = &end_time; | |
922 | } | |
923 | ||
924 | ret = do_sys_poll(ufds, nfds, to); | |
925 | ||
3075d9da CW |
926 | if (ret == -EINTR) { |
927 | restart_block->fn = do_restart_poll; | |
3075d9da CW |
928 | ret = -ERESTART_RESTARTBLOCK; |
929 | } | |
930 | return ret; | |
931 | } | |
932 | ||
5a8a82b1 | 933 | SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds, |
faf30900 | 934 | int, timeout_msecs) |
9f72949f | 935 | { |
8ff3e8e8 | 936 | struct timespec end_time, *to = NULL; |
3075d9da | 937 | int ret; |
9f72949f | 938 | |
8ff3e8e8 AV |
939 | if (timeout_msecs >= 0) { |
940 | to = &end_time; | |
941 | poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC, | |
942 | NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC)); | |
9f72949f DW |
943 | } |
944 | ||
8ff3e8e8 AV |
945 | ret = do_sys_poll(ufds, nfds, to); |
946 | ||
3075d9da CW |
947 | if (ret == -EINTR) { |
948 | struct restart_block *restart_block; | |
8ff3e8e8 | 949 | |
3075d9da CW |
950 | restart_block = ¤t_thread_info()->restart_block; |
951 | restart_block->fn = do_restart_poll; | |
8ff3e8e8 AV |
952 | restart_block->poll.ufds = ufds; |
953 | restart_block->poll.nfds = nfds; | |
954 | ||
955 | if (timeout_msecs >= 0) { | |
956 | restart_block->poll.tv_sec = end_time.tv_sec; | |
957 | restart_block->poll.tv_nsec = end_time.tv_nsec; | |
958 | restart_block->poll.has_timeout = 1; | |
959 | } else | |
960 | restart_block->poll.has_timeout = 0; | |
961 | ||
3075d9da CW |
962 | ret = -ERESTART_RESTARTBLOCK; |
963 | } | |
964 | return ret; | |
9f72949f DW |
965 | } |
966 | ||
d4e82042 HC |
967 | SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds, |
968 | struct timespec __user *, tsp, const sigset_t __user *, sigmask, | |
969 | size_t, sigsetsize) | |
9f72949f DW |
970 | { |
971 | sigset_t ksigmask, sigsaved; | |
8ff3e8e8 | 972 | struct timespec ts, end_time, *to = NULL; |
9f72949f DW |
973 | int ret; |
974 | ||
975 | if (tsp) { | |
976 | if (copy_from_user(&ts, tsp, sizeof(ts))) | |
977 | return -EFAULT; | |
978 | ||
8ff3e8e8 AV |
979 | to = &end_time; |
980 | if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) | |
981 | return -EINVAL; | |
9f72949f DW |
982 | } |
983 | ||
984 | if (sigmask) { | |
985 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
986 | if (sigsetsize != sizeof(sigset_t)) | |
987 | return -EINVAL; | |
988 | if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask))) | |
989 | return -EFAULT; | |
990 | ||
991 | sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
992 | sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); | |
993 | } | |
994 | ||
8ff3e8e8 | 995 | ret = do_sys_poll(ufds, nfds, to); |
9f72949f DW |
996 | |
997 | /* We can restart this syscall, usually */ | |
998 | if (ret == -EINTR) { | |
999 | /* | |
1000 | * Don't restore the signal mask yet. Let do_signal() deliver | |
1001 | * the signal on the way back to userspace, before the signal | |
1002 | * mask is restored. | |
1003 | */ | |
1004 | if (sigmask) { | |
1005 | memcpy(¤t->saved_sigmask, &sigsaved, | |
1006 | sizeof(sigsaved)); | |
4e4c22c7 | 1007 | set_restore_sigmask(); |
9f72949f DW |
1008 | } |
1009 | ret = -ERESTARTNOHAND; | |
1010 | } else if (sigmask) | |
1011 | sigprocmask(SIG_SETMASK, &sigsaved, NULL); | |
1012 | ||
8ff3e8e8 | 1013 | ret = poll_select_copy_remaining(&end_time, tsp, 0, ret); |
9f72949f DW |
1014 | |
1015 | return ret; | |
1016 | } |