Commit | Line | Data |
---|---|---|
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); | |
112 | pwq->error = 0; | |
113 | pwq->table = NULL; | |
70674f95 | 114 | pwq->inline_index = 0; |
1da177e4 LT |
115 | } |
116 | ||
117 | EXPORT_SYMBOL(poll_initwait); | |
118 | ||
70674f95 AK |
119 | static void free_poll_entry(struct poll_table_entry *entry) |
120 | { | |
ccf6780d | 121 | remove_wait_queue(entry->wait_address, &entry->wait); |
70674f95 AK |
122 | fput(entry->filp); |
123 | } | |
124 | ||
1da177e4 LT |
125 | void poll_freewait(struct poll_wqueues *pwq) |
126 | { | |
127 | struct poll_table_page * p = pwq->table; | |
70674f95 AK |
128 | int i; |
129 | for (i = 0; i < pwq->inline_index; i++) | |
130 | free_poll_entry(pwq->inline_entries + i); | |
1da177e4 LT |
131 | while (p) { |
132 | struct poll_table_entry * entry; | |
133 | struct poll_table_page *old; | |
134 | ||
135 | entry = p->entry; | |
136 | do { | |
137 | entry--; | |
70674f95 | 138 | free_poll_entry(entry); |
1da177e4 LT |
139 | } while (entry > p->entries); |
140 | old = p; | |
141 | p = p->next; | |
142 | free_page((unsigned long) old); | |
143 | } | |
144 | } | |
145 | ||
146 | EXPORT_SYMBOL(poll_freewait); | |
147 | ||
70674f95 | 148 | static struct poll_table_entry *poll_get_entry(poll_table *_p) |
1da177e4 LT |
149 | { |
150 | struct poll_wqueues *p = container_of(_p, struct poll_wqueues, pt); | |
151 | struct poll_table_page *table = p->table; | |
152 | ||
70674f95 AK |
153 | if (p->inline_index < N_INLINE_POLL_ENTRIES) |
154 | return p->inline_entries + p->inline_index++; | |
155 | ||
1da177e4 LT |
156 | if (!table || POLL_TABLE_FULL(table)) { |
157 | struct poll_table_page *new_table; | |
158 | ||
159 | new_table = (struct poll_table_page *) __get_free_page(GFP_KERNEL); | |
160 | if (!new_table) { | |
161 | p->error = -ENOMEM; | |
162 | __set_current_state(TASK_RUNNING); | |
70674f95 | 163 | return NULL; |
1da177e4 LT |
164 | } |
165 | new_table->entry = new_table->entries; | |
166 | new_table->next = table; | |
167 | p->table = new_table; | |
168 | table = new_table; | |
169 | } | |
170 | ||
70674f95 AK |
171 | return table->entry++; |
172 | } | |
173 | ||
174 | /* Add a new entry */ | |
175 | static void __pollwait(struct file *filp, wait_queue_head_t *wait_address, | |
176 | poll_table *p) | |
177 | { | |
178 | struct poll_table_entry *entry = poll_get_entry(p); | |
179 | if (!entry) | |
180 | return; | |
181 | get_file(filp); | |
182 | entry->filp = filp; | |
183 | entry->wait_address = wait_address; | |
184 | init_waitqueue_entry(&entry->wait, current); | |
ccf6780d | 185 | add_wait_queue(wait_address, &entry->wait); |
1da177e4 LT |
186 | } |
187 | ||
b773ad40 TG |
188 | /** |
189 | * poll_select_set_timeout - helper function to setup the timeout value | |
190 | * @to: pointer to timespec variable for the final timeout | |
191 | * @sec: seconds (from user space) | |
192 | * @nsec: nanoseconds (from user space) | |
193 | * | |
194 | * Note, we do not use a timespec for the user space value here, That | |
195 | * way we can use the function for timeval and compat interfaces as well. | |
196 | * | |
197 | * Returns -EINVAL if sec/nsec are not normalized. Otherwise 0. | |
198 | */ | |
199 | int poll_select_set_timeout(struct timespec *to, long sec, long nsec) | |
200 | { | |
201 | struct timespec ts = {.tv_sec = sec, .tv_nsec = nsec}; | |
202 | ||
203 | if (!timespec_valid(&ts)) | |
204 | return -EINVAL; | |
205 | ||
206 | /* Optimize for the zero timeout value here */ | |
207 | if (!sec && !nsec) { | |
208 | to->tv_sec = to->tv_nsec = 0; | |
209 | } else { | |
210 | ktime_get_ts(to); | |
211 | *to = timespec_add_safe(*to, ts); | |
212 | } | |
213 | return 0; | |
214 | } | |
215 | ||
216 | static int poll_select_copy_remaining(struct timespec *end_time, void __user *p, | |
217 | int timeval, int ret) | |
218 | { | |
219 | struct timespec rts; | |
220 | struct timeval rtv; | |
221 | ||
222 | if (!p) | |
223 | return ret; | |
224 | ||
225 | if (current->personality & STICKY_TIMEOUTS) | |
226 | goto sticky; | |
227 | ||
228 | /* No update for zero timeout */ | |
229 | if (!end_time->tv_sec && !end_time->tv_nsec) | |
230 | return ret; | |
231 | ||
232 | ktime_get_ts(&rts); | |
233 | rts = timespec_sub(*end_time, rts); | |
234 | if (rts.tv_sec < 0) | |
235 | rts.tv_sec = rts.tv_nsec = 0; | |
236 | ||
237 | if (timeval) { | |
238 | rtv.tv_sec = rts.tv_sec; | |
239 | rtv.tv_usec = rts.tv_nsec / NSEC_PER_USEC; | |
240 | ||
241 | if (!copy_to_user(p, &rtv, sizeof(rtv))) | |
242 | return ret; | |
243 | ||
244 | } else if (!copy_to_user(p, &rts, sizeof(rts))) | |
245 | return ret; | |
246 | ||
247 | /* | |
248 | * If an application puts its timeval in read-only memory, we | |
249 | * don't want the Linux-specific update to the timeval to | |
250 | * cause a fault after the select has completed | |
251 | * successfully. However, because we're not updating the | |
252 | * timeval, we can't restart the system call. | |
253 | */ | |
254 | ||
255 | sticky: | |
256 | if (ret == -ERESTARTNOHAND) | |
257 | ret = -EINTR; | |
258 | return ret; | |
259 | } | |
260 | ||
1da177e4 LT |
261 | #define FDS_IN(fds, n) (fds->in + n) |
262 | #define FDS_OUT(fds, n) (fds->out + n) | |
263 | #define FDS_EX(fds, n) (fds->ex + n) | |
264 | ||
265 | #define BITS(fds, n) (*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n)) | |
266 | ||
267 | static int max_select_fd(unsigned long n, fd_set_bits *fds) | |
268 | { | |
269 | unsigned long *open_fds; | |
270 | unsigned long set; | |
271 | int max; | |
badf1662 | 272 | struct fdtable *fdt; |
1da177e4 LT |
273 | |
274 | /* handle last in-complete long-word first */ | |
275 | set = ~(~0UL << (n & (__NFDBITS-1))); | |
276 | n /= __NFDBITS; | |
badf1662 DS |
277 | fdt = files_fdtable(current->files); |
278 | open_fds = fdt->open_fds->fds_bits+n; | |
1da177e4 LT |
279 | max = 0; |
280 | if (set) { | |
281 | set &= BITS(fds, n); | |
282 | if (set) { | |
283 | if (!(set & ~*open_fds)) | |
284 | goto get_max; | |
285 | return -EBADF; | |
286 | } | |
287 | } | |
288 | while (n) { | |
289 | open_fds--; | |
290 | n--; | |
291 | set = BITS(fds, n); | |
292 | if (!set) | |
293 | continue; | |
294 | if (set & ~*open_fds) | |
295 | return -EBADF; | |
296 | if (max) | |
297 | continue; | |
298 | get_max: | |
299 | do { | |
300 | max++; | |
301 | set >>= 1; | |
302 | } while (set); | |
303 | max += n * __NFDBITS; | |
304 | } | |
305 | ||
306 | return max; | |
307 | } | |
308 | ||
1da177e4 LT |
309 | #define POLLIN_SET (POLLRDNORM | POLLRDBAND | POLLIN | POLLHUP | POLLERR) |
310 | #define POLLOUT_SET (POLLWRBAND | POLLWRNORM | POLLOUT | POLLERR) | |
311 | #define POLLEX_SET (POLLPRI) | |
312 | ||
8ff3e8e8 | 313 | int do_select(int n, fd_set_bits *fds, struct timespec *end_time) |
1da177e4 | 314 | { |
8ff3e8e8 | 315 | ktime_t expire, *to = NULL; |
1da177e4 LT |
316 | struct poll_wqueues table; |
317 | poll_table *wait; | |
8ff3e8e8 | 318 | int retval, i, timed_out = 0; |
90d6e24a | 319 | unsigned long slack = 0; |
1da177e4 | 320 | |
b835996f | 321 | rcu_read_lock(); |
1da177e4 | 322 | retval = max_select_fd(n, fds); |
b835996f | 323 | rcu_read_unlock(); |
1da177e4 LT |
324 | |
325 | if (retval < 0) | |
326 | return retval; | |
327 | n = retval; | |
328 | ||
329 | poll_initwait(&table); | |
330 | wait = &table.pt; | |
8ff3e8e8 | 331 | if (end_time && !end_time->tv_sec && !end_time->tv_nsec) { |
1da177e4 | 332 | wait = NULL; |
8ff3e8e8 AV |
333 | timed_out = 1; |
334 | } | |
335 | ||
96d2ab48 | 336 | if (end_time && !timed_out) |
90d6e24a AV |
337 | slack = estimate_accuracy(end_time); |
338 | ||
1da177e4 LT |
339 | retval = 0; |
340 | for (;;) { | |
341 | unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp; | |
342 | ||
343 | set_current_state(TASK_INTERRUPTIBLE); | |
344 | ||
345 | inp = fds->in; outp = fds->out; exp = fds->ex; | |
346 | rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex; | |
347 | ||
348 | for (i = 0; i < n; ++rinp, ++routp, ++rexp) { | |
349 | unsigned long in, out, ex, all_bits, bit = 1, mask, j; | |
350 | unsigned long res_in = 0, res_out = 0, res_ex = 0; | |
99ac48f5 | 351 | const struct file_operations *f_op = NULL; |
1da177e4 LT |
352 | struct file *file = NULL; |
353 | ||
354 | in = *inp++; out = *outp++; ex = *exp++; | |
355 | all_bits = in | out | ex; | |
356 | if (all_bits == 0) { | |
357 | i += __NFDBITS; | |
358 | continue; | |
359 | } | |
360 | ||
361 | for (j = 0; j < __NFDBITS; ++j, ++i, bit <<= 1) { | |
e4a1f129 | 362 | int fput_needed; |
1da177e4 LT |
363 | if (i >= n) |
364 | break; | |
365 | if (!(bit & all_bits)) | |
366 | continue; | |
e4a1f129 | 367 | file = fget_light(i, &fput_needed); |
1da177e4 LT |
368 | if (file) { |
369 | f_op = file->f_op; | |
370 | mask = DEFAULT_POLLMASK; | |
371 | if (f_op && f_op->poll) | |
372 | mask = (*f_op->poll)(file, retval ? NULL : wait); | |
e4a1f129 | 373 | fput_light(file, fput_needed); |
1da177e4 LT |
374 | if ((mask & POLLIN_SET) && (in & bit)) { |
375 | res_in |= bit; | |
376 | retval++; | |
377 | } | |
378 | if ((mask & POLLOUT_SET) && (out & bit)) { | |
379 | res_out |= bit; | |
380 | retval++; | |
381 | } | |
382 | if ((mask & POLLEX_SET) && (ex & bit)) { | |
383 | res_ex |= bit; | |
384 | retval++; | |
385 | } | |
386 | } | |
1da177e4 LT |
387 | } |
388 | if (res_in) | |
389 | *rinp = res_in; | |
390 | if (res_out) | |
391 | *routp = res_out; | |
392 | if (res_ex) | |
393 | *rexp = res_ex; | |
55d85384 | 394 | cond_resched(); |
1da177e4 LT |
395 | } |
396 | wait = NULL; | |
8ff3e8e8 | 397 | if (retval || timed_out || signal_pending(current)) |
1da177e4 | 398 | break; |
f5264481 | 399 | if (table.error) { |
1da177e4 LT |
400 | retval = table.error; |
401 | break; | |
402 | } | |
9f72949f | 403 | |
8ff3e8e8 AV |
404 | /* |
405 | * If this is the first loop and we have a timeout | |
406 | * given, then we convert to ktime_t and set the to | |
407 | * pointer to the expiry value. | |
408 | */ | |
409 | if (end_time && !to) { | |
410 | expire = timespec_to_ktime(*end_time); | |
411 | to = &expire; | |
9f72949f | 412 | } |
8ff3e8e8 | 413 | |
90d6e24a | 414 | if (!schedule_hrtimeout_range(to, slack, HRTIMER_MODE_ABS)) |
8ff3e8e8 | 415 | timed_out = 1; |
1da177e4 LT |
416 | } |
417 | __set_current_state(TASK_RUNNING); | |
418 | ||
419 | poll_freewait(&table); | |
420 | ||
1da177e4 LT |
421 | return retval; |
422 | } | |
423 | ||
1da177e4 LT |
424 | /* |
425 | * We can actually return ERESTARTSYS instead of EINTR, but I'd | |
426 | * like to be certain this leads to no problems. So I return | |
427 | * EINTR just for safety. | |
428 | * | |
429 | * Update: ERESTARTSYS breaks at least the xview clock binary, so | |
430 | * I'm trying ERESTARTNOHAND which restart only when you want to. | |
431 | */ | |
432 | #define MAX_SELECT_SECONDS \ | |
433 | ((unsigned long) (MAX_SCHEDULE_TIMEOUT / HZ)-1) | |
434 | ||
a2dcb44c | 435 | int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp, |
8ff3e8e8 | 436 | fd_set __user *exp, struct timespec *end_time) |
1da177e4 LT |
437 | { |
438 | fd_set_bits fds; | |
29ff2db5 | 439 | void *bits; |
bbea9f69 | 440 | int ret, max_fds; |
b04eb6aa | 441 | unsigned int size; |
badf1662 | 442 | struct fdtable *fdt; |
70674f95 | 443 | /* Allocate small arguments on the stack to save memory and be faster */ |
30c14e40 | 444 | long stack_fds[SELECT_STACK_ALLOC/sizeof(long)]; |
1da177e4 | 445 | |
1da177e4 LT |
446 | ret = -EINVAL; |
447 | if (n < 0) | |
448 | goto out_nofds; | |
449 | ||
bbea9f69 | 450 | /* max_fds can increase, so grab it once to avoid race */ |
b835996f | 451 | rcu_read_lock(); |
badf1662 | 452 | fdt = files_fdtable(current->files); |
bbea9f69 | 453 | max_fds = fdt->max_fds; |
b835996f | 454 | rcu_read_unlock(); |
bbea9f69 VL |
455 | if (n > max_fds) |
456 | n = max_fds; | |
1da177e4 LT |
457 | |
458 | /* | |
459 | * We need 6 bitmaps (in/out/ex for both incoming and outgoing), | |
460 | * since we used fdset we need to allocate memory in units of | |
461 | * long-words. | |
462 | */ | |
1da177e4 | 463 | size = FDS_BYTES(n); |
b04eb6aa MBJ |
464 | bits = stack_fds; |
465 | if (size > sizeof(stack_fds) / 6) { | |
466 | /* Not enough space in on-stack array; must use kmalloc */ | |
467 | ret = -ENOMEM; | |
70674f95 | 468 | bits = kmalloc(6 * size, GFP_KERNEL); |
b04eb6aa MBJ |
469 | if (!bits) |
470 | goto out_nofds; | |
471 | } | |
29ff2db5 AM |
472 | fds.in = bits; |
473 | fds.out = bits + size; | |
474 | fds.ex = bits + 2*size; | |
475 | fds.res_in = bits + 3*size; | |
476 | fds.res_out = bits + 4*size; | |
477 | fds.res_ex = bits + 5*size; | |
1da177e4 LT |
478 | |
479 | if ((ret = get_fd_set(n, inp, fds.in)) || | |
480 | (ret = get_fd_set(n, outp, fds.out)) || | |
481 | (ret = get_fd_set(n, exp, fds.ex))) | |
482 | goto out; | |
483 | zero_fd_set(n, fds.res_in); | |
484 | zero_fd_set(n, fds.res_out); | |
485 | zero_fd_set(n, fds.res_ex); | |
486 | ||
8ff3e8e8 | 487 | ret = do_select(n, &fds, end_time); |
1da177e4 LT |
488 | |
489 | if (ret < 0) | |
490 | goto out; | |
491 | if (!ret) { | |
492 | ret = -ERESTARTNOHAND; | |
493 | if (signal_pending(current)) | |
494 | goto out; | |
495 | ret = 0; | |
496 | } | |
497 | ||
498 | if (set_fd_set(n, inp, fds.res_in) || | |
499 | set_fd_set(n, outp, fds.res_out) || | |
500 | set_fd_set(n, exp, fds.res_ex)) | |
501 | ret = -EFAULT; | |
502 | ||
503 | out: | |
70674f95 AK |
504 | if (bits != stack_fds) |
505 | kfree(bits); | |
1da177e4 LT |
506 | out_nofds: |
507 | return ret; | |
508 | } | |
509 | ||
9f72949f DW |
510 | asmlinkage long sys_select(int n, fd_set __user *inp, fd_set __user *outp, |
511 | fd_set __user *exp, struct timeval __user *tvp) | |
512 | { | |
8ff3e8e8 | 513 | struct timespec end_time, *to = NULL; |
9f72949f DW |
514 | struct timeval tv; |
515 | int ret; | |
516 | ||
517 | if (tvp) { | |
518 | if (copy_from_user(&tv, tvp, sizeof(tv))) | |
519 | return -EFAULT; | |
520 | ||
8ff3e8e8 | 521 | to = &end_time; |
4d36a9e6 AV |
522 | if (poll_select_set_timeout(to, |
523 | tv.tv_sec + (tv.tv_usec / USEC_PER_SEC), | |
524 | (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC)) | |
9f72949f | 525 | return -EINVAL; |
9f72949f DW |
526 | } |
527 | ||
8ff3e8e8 AV |
528 | ret = core_sys_select(n, inp, outp, exp, to); |
529 | ret = poll_select_copy_remaining(&end_time, tvp, 1, ret); | |
9f72949f DW |
530 | |
531 | return ret; | |
532 | } | |
533 | ||
f3de272b | 534 | #ifdef HAVE_SET_RESTORE_SIGMASK |
9f72949f DW |
535 | asmlinkage long sys_pselect7(int n, fd_set __user *inp, fd_set __user *outp, |
536 | fd_set __user *exp, struct timespec __user *tsp, | |
537 | const sigset_t __user *sigmask, size_t sigsetsize) | |
538 | { | |
9f72949f | 539 | sigset_t ksigmask, sigsaved; |
8ff3e8e8 | 540 | struct timespec ts, end_time, *to = NULL; |
9f72949f DW |
541 | int ret; |
542 | ||
543 | if (tsp) { | |
544 | if (copy_from_user(&ts, tsp, sizeof(ts))) | |
545 | return -EFAULT; | |
546 | ||
8ff3e8e8 AV |
547 | to = &end_time; |
548 | if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) | |
9f72949f | 549 | return -EINVAL; |
9f72949f DW |
550 | } |
551 | ||
552 | if (sigmask) { | |
553 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
554 | if (sigsetsize != sizeof(sigset_t)) | |
555 | return -EINVAL; | |
556 | if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask))) | |
557 | return -EFAULT; | |
558 | ||
559 | sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
560 | sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); | |
561 | } | |
562 | ||
8ff3e8e8 AV |
563 | ret = core_sys_select(n, inp, outp, exp, &end_time); |
564 | ret = poll_select_copy_remaining(&end_time, tsp, 0, ret); | |
9f72949f DW |
565 | |
566 | if (ret == -ERESTARTNOHAND) { | |
567 | /* | |
568 | * Don't restore the signal mask yet. Let do_signal() deliver | |
569 | * the signal on the way back to userspace, before the signal | |
570 | * mask is restored. | |
571 | */ | |
572 | if (sigmask) { | |
573 | memcpy(¤t->saved_sigmask, &sigsaved, | |
574 | sizeof(sigsaved)); | |
4e4c22c7 | 575 | set_restore_sigmask(); |
9f72949f DW |
576 | } |
577 | } else if (sigmask) | |
578 | sigprocmask(SIG_SETMASK, &sigsaved, NULL); | |
579 | ||
580 | return ret; | |
581 | } | |
582 | ||
583 | /* | |
584 | * Most architectures can't handle 7-argument syscalls. So we provide a | |
585 | * 6-argument version where the sixth argument is a pointer to a structure | |
586 | * which has a pointer to the sigset_t itself followed by a size_t containing | |
587 | * the sigset size. | |
588 | */ | |
589 | asmlinkage long sys_pselect6(int n, fd_set __user *inp, fd_set __user *outp, | |
590 | fd_set __user *exp, struct timespec __user *tsp, void __user *sig) | |
591 | { | |
592 | size_t sigsetsize = 0; | |
593 | sigset_t __user *up = NULL; | |
594 | ||
595 | if (sig) { | |
596 | if (!access_ok(VERIFY_READ, sig, sizeof(void *)+sizeof(size_t)) | |
e110ab94 | 597 | || __get_user(up, (sigset_t __user * __user *)sig) |
9f72949f | 598 | || __get_user(sigsetsize, |
e110ab94 | 599 | (size_t __user *)(sig+sizeof(void *)))) |
9f72949f DW |
600 | return -EFAULT; |
601 | } | |
602 | ||
603 | return sys_pselect7(n, inp, outp, exp, tsp, up, sigsetsize); | |
604 | } | |
f3de272b | 605 | #endif /* HAVE_SET_RESTORE_SIGMASK */ |
9f72949f | 606 | |
1da177e4 LT |
607 | struct poll_list { |
608 | struct poll_list *next; | |
609 | int len; | |
610 | struct pollfd entries[0]; | |
611 | }; | |
612 | ||
613 | #define POLLFD_PER_PAGE ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd)) | |
614 | ||
4a4b69f7 VL |
615 | /* |
616 | * Fish for pollable events on the pollfd->fd file descriptor. We're only | |
617 | * interested in events matching the pollfd->events mask, and the result | |
618 | * matching that mask is both recorded in pollfd->revents and returned. The | |
619 | * pwait poll_table will be used by the fd-provided poll handler for waiting, | |
620 | * if non-NULL. | |
621 | */ | |
622 | static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait) | |
1da177e4 | 623 | { |
4a4b69f7 VL |
624 | unsigned int mask; |
625 | int fd; | |
626 | ||
627 | mask = 0; | |
628 | fd = pollfd->fd; | |
629 | if (fd >= 0) { | |
630 | int fput_needed; | |
631 | struct file * file; | |
632 | ||
633 | file = fget_light(fd, &fput_needed); | |
634 | mask = POLLNVAL; | |
635 | if (file != NULL) { | |
636 | mask = DEFAULT_POLLMASK; | |
637 | if (file->f_op && file->f_op->poll) | |
638 | mask = file->f_op->poll(file, pwait); | |
639 | /* Mask out unneeded events. */ | |
640 | mask &= pollfd->events | POLLERR | POLLHUP; | |
641 | fput_light(file, fput_needed); | |
1da177e4 | 642 | } |
1da177e4 | 643 | } |
4a4b69f7 VL |
644 | pollfd->revents = mask; |
645 | ||
646 | return mask; | |
1da177e4 LT |
647 | } |
648 | ||
649 | static int do_poll(unsigned int nfds, struct poll_list *list, | |
8ff3e8e8 | 650 | struct poll_wqueues *wait, struct timespec *end_time) |
1da177e4 | 651 | { |
1da177e4 | 652 | poll_table* pt = &wait->pt; |
8ff3e8e8 AV |
653 | ktime_t expire, *to = NULL; |
654 | int timed_out = 0, count = 0; | |
90d6e24a | 655 | unsigned long slack = 0; |
1da177e4 | 656 | |
9f72949f | 657 | /* Optimise the no-wait case */ |
8ff3e8e8 | 658 | if (end_time && !end_time->tv_sec && !end_time->tv_nsec) { |
1da177e4 | 659 | pt = NULL; |
8ff3e8e8 AV |
660 | timed_out = 1; |
661 | } | |
9bf084f7 | 662 | |
96d2ab48 | 663 | if (end_time && !timed_out) |
90d6e24a AV |
664 | slack = estimate_accuracy(end_time); |
665 | ||
1da177e4 LT |
666 | for (;;) { |
667 | struct poll_list *walk; | |
9f72949f | 668 | |
1da177e4 | 669 | set_current_state(TASK_INTERRUPTIBLE); |
4a4b69f7 VL |
670 | for (walk = list; walk != NULL; walk = walk->next) { |
671 | struct pollfd * pfd, * pfd_end; | |
672 | ||
673 | pfd = walk->entries; | |
674 | pfd_end = pfd + walk->len; | |
675 | for (; pfd != pfd_end; pfd++) { | |
676 | /* | |
677 | * Fish for events. If we found one, record it | |
678 | * and kill the poll_table, so we don't | |
679 | * needlessly register any other waiters after | |
680 | * this. They'll get immediately deregistered | |
681 | * when we break out and return. | |
682 | */ | |
683 | if (do_pollfd(pfd, pt)) { | |
684 | count++; | |
685 | pt = NULL; | |
686 | } | |
687 | } | |
1da177e4 | 688 | } |
4a4b69f7 VL |
689 | /* |
690 | * All waiters have already been registered, so don't provide | |
691 | * a poll_table to them on the next loop iteration. | |
692 | */ | |
1da177e4 | 693 | pt = NULL; |
9bf084f7 ON |
694 | if (!count) { |
695 | count = wait->error; | |
696 | if (signal_pending(current)) | |
697 | count = -EINTR; | |
698 | } | |
8ff3e8e8 | 699 | if (count || timed_out) |
1da177e4 | 700 | break; |
9f72949f | 701 | |
8ff3e8e8 AV |
702 | /* |
703 | * If this is the first loop and we have a timeout | |
704 | * given, then we convert to ktime_t and set the to | |
705 | * pointer to the expiry value. | |
706 | */ | |
707 | if (end_time && !to) { | |
708 | expire = timespec_to_ktime(*end_time); | |
709 | to = &expire; | |
9f72949f DW |
710 | } |
711 | ||
90d6e24a | 712 | if (!schedule_hrtimeout_range(to, slack, HRTIMER_MODE_ABS)) |
8ff3e8e8 | 713 | timed_out = 1; |
1da177e4 LT |
714 | } |
715 | __set_current_state(TASK_RUNNING); | |
716 | return count; | |
717 | } | |
718 | ||
70674f95 AK |
719 | #define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \ |
720 | sizeof(struct pollfd)) | |
721 | ||
8ff3e8e8 AV |
722 | int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds, |
723 | struct timespec *end_time) | |
1da177e4 LT |
724 | { |
725 | struct poll_wqueues table; | |
252e5725 | 726 | int err = -EFAULT, fdcount, len, size; |
30c14e40 JS |
727 | /* Allocate small arguments on the stack to save memory and be |
728 | faster - use long to make sure the buffer is aligned properly | |
729 | on 64 bit archs to avoid unaligned access */ | |
730 | long stack_pps[POLL_STACK_ALLOC/sizeof(long)]; | |
252e5725 ON |
731 | struct poll_list *const head = (struct poll_list *)stack_pps; |
732 | struct poll_list *walk = head; | |
733 | unsigned long todo = nfds; | |
1da177e4 | 734 | |
4e6fd33b | 735 | if (nfds > current->signal->rlim[RLIMIT_NOFILE].rlim_cur) |
1da177e4 LT |
736 | return -EINVAL; |
737 | ||
252e5725 ON |
738 | len = min_t(unsigned int, nfds, N_STACK_PPS); |
739 | for (;;) { | |
740 | walk->next = NULL; | |
741 | walk->len = len; | |
742 | if (!len) | |
743 | break; | |
1da177e4 | 744 | |
252e5725 ON |
745 | if (copy_from_user(walk->entries, ufds + nfds-todo, |
746 | sizeof(struct pollfd) * walk->len)) | |
747 | goto out_fds; | |
748 | ||
749 | todo -= walk->len; | |
750 | if (!todo) | |
751 | break; | |
1da177e4 | 752 | |
252e5725 ON |
753 | len = min(todo, POLLFD_PER_PAGE); |
754 | size = sizeof(struct poll_list) + sizeof(struct pollfd) * len; | |
755 | walk = walk->next = kmalloc(size, GFP_KERNEL); | |
756 | if (!walk) { | |
757 | err = -ENOMEM; | |
1da177e4 LT |
758 | goto out_fds; |
759 | } | |
1da177e4 | 760 | } |
9f72949f | 761 | |
252e5725 | 762 | poll_initwait(&table); |
8ff3e8e8 | 763 | fdcount = do_poll(nfds, head, &table, end_time); |
252e5725 | 764 | poll_freewait(&table); |
1da177e4 | 765 | |
252e5725 | 766 | for (walk = head; walk; walk = walk->next) { |
1da177e4 LT |
767 | struct pollfd *fds = walk->entries; |
768 | int j; | |
769 | ||
252e5725 ON |
770 | for (j = 0; j < walk->len; j++, ufds++) |
771 | if (__put_user(fds[j].revents, &ufds->revents)) | |
1da177e4 | 772 | goto out_fds; |
1da177e4 | 773 | } |
252e5725 | 774 | |
1da177e4 | 775 | err = fdcount; |
1da177e4 | 776 | out_fds: |
252e5725 ON |
777 | walk = head->next; |
778 | while (walk) { | |
779 | struct poll_list *pos = walk; | |
780 | walk = walk->next; | |
781 | kfree(pos); | |
1da177e4 | 782 | } |
252e5725 | 783 | |
1da177e4 LT |
784 | return err; |
785 | } | |
9f72949f | 786 | |
3075d9da CW |
787 | static long do_restart_poll(struct restart_block *restart_block) |
788 | { | |
8ff3e8e8 AV |
789 | struct pollfd __user *ufds = restart_block->poll.ufds; |
790 | int nfds = restart_block->poll.nfds; | |
791 | struct timespec *to = NULL, end_time; | |
3075d9da CW |
792 | int ret; |
793 | ||
8ff3e8e8 AV |
794 | if (restart_block->poll.has_timeout) { |
795 | end_time.tv_sec = restart_block->poll.tv_sec; | |
796 | end_time.tv_nsec = restart_block->poll.tv_nsec; | |
797 | to = &end_time; | |
798 | } | |
799 | ||
800 | ret = do_sys_poll(ufds, nfds, to); | |
801 | ||
3075d9da CW |
802 | if (ret == -EINTR) { |
803 | restart_block->fn = do_restart_poll; | |
3075d9da CW |
804 | ret = -ERESTART_RESTARTBLOCK; |
805 | } | |
806 | return ret; | |
807 | } | |
808 | ||
9f72949f DW |
809 | asmlinkage long sys_poll(struct pollfd __user *ufds, unsigned int nfds, |
810 | long timeout_msecs) | |
811 | { | |
8ff3e8e8 | 812 | struct timespec end_time, *to = NULL; |
3075d9da | 813 | int ret; |
9f72949f | 814 | |
8ff3e8e8 AV |
815 | if (timeout_msecs >= 0) { |
816 | to = &end_time; | |
817 | poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC, | |
818 | NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC)); | |
9f72949f DW |
819 | } |
820 | ||
8ff3e8e8 AV |
821 | ret = do_sys_poll(ufds, nfds, to); |
822 | ||
3075d9da CW |
823 | if (ret == -EINTR) { |
824 | struct restart_block *restart_block; | |
8ff3e8e8 | 825 | |
3075d9da CW |
826 | restart_block = ¤t_thread_info()->restart_block; |
827 | restart_block->fn = do_restart_poll; | |
8ff3e8e8 AV |
828 | restart_block->poll.ufds = ufds; |
829 | restart_block->poll.nfds = nfds; | |
830 | ||
831 | if (timeout_msecs >= 0) { | |
832 | restart_block->poll.tv_sec = end_time.tv_sec; | |
833 | restart_block->poll.tv_nsec = end_time.tv_nsec; | |
834 | restart_block->poll.has_timeout = 1; | |
835 | } else | |
836 | restart_block->poll.has_timeout = 0; | |
837 | ||
3075d9da CW |
838 | ret = -ERESTART_RESTARTBLOCK; |
839 | } | |
840 | return ret; | |
9f72949f DW |
841 | } |
842 | ||
f3de272b | 843 | #ifdef HAVE_SET_RESTORE_SIGMASK |
9f72949f DW |
844 | asmlinkage long sys_ppoll(struct pollfd __user *ufds, unsigned int nfds, |
845 | struct timespec __user *tsp, const sigset_t __user *sigmask, | |
846 | size_t sigsetsize) | |
847 | { | |
848 | sigset_t ksigmask, sigsaved; | |
8ff3e8e8 | 849 | struct timespec ts, end_time, *to = NULL; |
9f72949f DW |
850 | int ret; |
851 | ||
852 | if (tsp) { | |
853 | if (copy_from_user(&ts, tsp, sizeof(ts))) | |
854 | return -EFAULT; | |
855 | ||
8ff3e8e8 AV |
856 | to = &end_time; |
857 | if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) | |
858 | return -EINVAL; | |
9f72949f DW |
859 | } |
860 | ||
861 | if (sigmask) { | |
862 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
863 | if (sigsetsize != sizeof(sigset_t)) | |
864 | return -EINVAL; | |
865 | if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask))) | |
866 | return -EFAULT; | |
867 | ||
868 | sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
869 | sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); | |
870 | } | |
871 | ||
8ff3e8e8 | 872 | ret = do_sys_poll(ufds, nfds, to); |
9f72949f DW |
873 | |
874 | /* We can restart this syscall, usually */ | |
875 | if (ret == -EINTR) { | |
876 | /* | |
877 | * Don't restore the signal mask yet. Let do_signal() deliver | |
878 | * the signal on the way back to userspace, before the signal | |
879 | * mask is restored. | |
880 | */ | |
881 | if (sigmask) { | |
882 | memcpy(¤t->saved_sigmask, &sigsaved, | |
883 | sizeof(sigsaved)); | |
4e4c22c7 | 884 | set_restore_sigmask(); |
9f72949f DW |
885 | } |
886 | ret = -ERESTARTNOHAND; | |
887 | } else if (sigmask) | |
888 | sigprocmask(SIG_SETMASK, &sigsaved, NULL); | |
889 | ||
8ff3e8e8 | 890 | ret = poll_select_copy_remaining(&end_time, tsp, 0, ret); |
9f72949f DW |
891 | |
892 | return ret; | |
893 | } | |
f3de272b | 894 | #endif /* HAVE_SET_RESTORE_SIGMASK */ |