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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 | ||
44 | static unsigned long __estimate_accuracy(struct timespec *tv) | |
45 | { | |
46 | unsigned long slack; | |
47 | int divfactor = 1000; | |
48 | ||
49 | if (task_nice(current)) | |
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; | |
57 | return slack; | |
58 | } | |
59 | ||
60 | static unsigned long estimate_accuracy(struct timespec *tv) | |
61 | { | |
62 | unsigned long ret; | |
63 | struct timespec now; | |
64 | ||
65 | /* | |
66 | * Realtime tasks get a slack of 0 for obvious reasons. | |
67 | */ | |
68 | ||
69 | if (current->policy == SCHED_FIFO || | |
70 | current->policy == SCHED_RR) | |
71 | return 0; | |
72 | ||
73 | ktime_get_ts(&now); | |
74 | now = timespec_sub(*tv, now); | |
75 | ret = __estimate_accuracy(&now); | |
76 | if (ret < current->timer_slack_ns) | |
77 | return current->timer_slack_ns; | |
78 | return ret; | |
79 | } | |
80 | ||
81 | ||
82 | ||
1da177e4 LT |
83 | struct poll_table_page { |
84 | struct poll_table_page * next; | |
85 | struct poll_table_entry * entry; | |
86 | struct poll_table_entry entries[0]; | |
87 | }; | |
88 | ||
89 | #define POLL_TABLE_FULL(table) \ | |
90 | ((unsigned long)((table)->entry+1) > PAGE_SIZE + (unsigned long)(table)) | |
91 | ||
92 | /* | |
93 | * Ok, Peter made a complicated, but straightforward multiple_wait() function. | |
94 | * I have rewritten this, taking some shortcuts: This code may not be easy to | |
95 | * follow, but it should be free of race-conditions, and it's practical. If you | |
96 | * understand what I'm doing here, then you understand how the linux | |
97 | * sleep/wakeup mechanism works. | |
98 | * | |
99 | * Two very simple procedures, poll_wait() and poll_freewait() make all the | |
100 | * work. poll_wait() is an inline-function defined in <linux/poll.h>, | |
101 | * as all select/poll functions have to call it to add an entry to the | |
102 | * poll table. | |
103 | */ | |
75c96f85 AB |
104 | static void __pollwait(struct file *filp, wait_queue_head_t *wait_address, |
105 | poll_table *p); | |
1da177e4 LT |
106 | |
107 | void poll_initwait(struct poll_wqueues *pwq) | |
108 | { | |
109 | init_poll_funcptr(&pwq->pt, __pollwait); | |
110 | pwq->error = 0; | |
111 | pwq->table = NULL; | |
70674f95 | 112 | pwq->inline_index = 0; |
1da177e4 LT |
113 | } |
114 | ||
115 | EXPORT_SYMBOL(poll_initwait); | |
116 | ||
70674f95 AK |
117 | static void free_poll_entry(struct poll_table_entry *entry) |
118 | { | |
ccf6780d | 119 | remove_wait_queue(entry->wait_address, &entry->wait); |
70674f95 AK |
120 | fput(entry->filp); |
121 | } | |
122 | ||
1da177e4 LT |
123 | void poll_freewait(struct poll_wqueues *pwq) |
124 | { | |
125 | struct poll_table_page * p = pwq->table; | |
70674f95 AK |
126 | int i; |
127 | for (i = 0; i < pwq->inline_index; i++) | |
128 | free_poll_entry(pwq->inline_entries + i); | |
1da177e4 LT |
129 | while (p) { |
130 | struct poll_table_entry * entry; | |
131 | struct poll_table_page *old; | |
132 | ||
133 | entry = p->entry; | |
134 | do { | |
135 | entry--; | |
70674f95 | 136 | free_poll_entry(entry); |
1da177e4 LT |
137 | } while (entry > p->entries); |
138 | old = p; | |
139 | p = p->next; | |
140 | free_page((unsigned long) old); | |
141 | } | |
142 | } | |
143 | ||
144 | EXPORT_SYMBOL(poll_freewait); | |
145 | ||
70674f95 | 146 | static struct poll_table_entry *poll_get_entry(poll_table *_p) |
1da177e4 LT |
147 | { |
148 | struct poll_wqueues *p = container_of(_p, struct poll_wqueues, pt); | |
149 | struct poll_table_page *table = p->table; | |
150 | ||
70674f95 AK |
151 | if (p->inline_index < N_INLINE_POLL_ENTRIES) |
152 | return p->inline_entries + p->inline_index++; | |
153 | ||
1da177e4 LT |
154 | if (!table || POLL_TABLE_FULL(table)) { |
155 | struct poll_table_page *new_table; | |
156 | ||
157 | new_table = (struct poll_table_page *) __get_free_page(GFP_KERNEL); | |
158 | if (!new_table) { | |
159 | p->error = -ENOMEM; | |
160 | __set_current_state(TASK_RUNNING); | |
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 | ||
172 | /* Add a new entry */ | |
173 | static void __pollwait(struct file *filp, wait_queue_head_t *wait_address, | |
174 | poll_table *p) | |
175 | { | |
176 | struct poll_table_entry *entry = poll_get_entry(p); | |
177 | if (!entry) | |
178 | return; | |
179 | get_file(filp); | |
180 | entry->filp = filp; | |
181 | entry->wait_address = wait_address; | |
182 | init_waitqueue_entry(&entry->wait, current); | |
ccf6780d | 183 | add_wait_queue(wait_address, &entry->wait); |
1da177e4 LT |
184 | } |
185 | ||
b773ad40 TG |
186 | /** |
187 | * poll_select_set_timeout - helper function to setup the timeout value | |
188 | * @to: pointer to timespec variable for the final timeout | |
189 | * @sec: seconds (from user space) | |
190 | * @nsec: nanoseconds (from user space) | |
191 | * | |
192 | * Note, we do not use a timespec for the user space value here, That | |
193 | * way we can use the function for timeval and compat interfaces as well. | |
194 | * | |
195 | * Returns -EINVAL if sec/nsec are not normalized. Otherwise 0. | |
196 | */ | |
197 | int poll_select_set_timeout(struct timespec *to, long sec, long nsec) | |
198 | { | |
199 | struct timespec ts = {.tv_sec = sec, .tv_nsec = nsec}; | |
200 | ||
201 | if (!timespec_valid(&ts)) | |
202 | return -EINVAL; | |
203 | ||
204 | /* Optimize for the zero timeout value here */ | |
205 | if (!sec && !nsec) { | |
206 | to->tv_sec = to->tv_nsec = 0; | |
207 | } else { | |
208 | ktime_get_ts(to); | |
209 | *to = timespec_add_safe(*to, ts); | |
210 | } | |
211 | return 0; | |
212 | } | |
213 | ||
214 | static int poll_select_copy_remaining(struct timespec *end_time, void __user *p, | |
215 | int timeval, int ret) | |
216 | { | |
217 | struct timespec rts; | |
218 | struct timeval rtv; | |
219 | ||
220 | if (!p) | |
221 | return ret; | |
222 | ||
223 | if (current->personality & STICKY_TIMEOUTS) | |
224 | goto sticky; | |
225 | ||
226 | /* No update for zero timeout */ | |
227 | if (!end_time->tv_sec && !end_time->tv_nsec) | |
228 | return ret; | |
229 | ||
230 | ktime_get_ts(&rts); | |
231 | rts = timespec_sub(*end_time, rts); | |
232 | if (rts.tv_sec < 0) | |
233 | rts.tv_sec = rts.tv_nsec = 0; | |
234 | ||
235 | if (timeval) { | |
236 | rtv.tv_sec = rts.tv_sec; | |
237 | rtv.tv_usec = rts.tv_nsec / NSEC_PER_USEC; | |
238 | ||
239 | if (!copy_to_user(p, &rtv, sizeof(rtv))) | |
240 | return ret; | |
241 | ||
242 | } else if (!copy_to_user(p, &rts, sizeof(rts))) | |
243 | return ret; | |
244 | ||
245 | /* | |
246 | * If an application puts its timeval in read-only memory, we | |
247 | * don't want the Linux-specific update to the timeval to | |
248 | * cause a fault after the select has completed | |
249 | * successfully. However, because we're not updating the | |
250 | * timeval, we can't restart the system call. | |
251 | */ | |
252 | ||
253 | sticky: | |
254 | if (ret == -ERESTARTNOHAND) | |
255 | ret = -EINTR; | |
256 | return ret; | |
257 | } | |
258 | ||
1da177e4 LT |
259 | #define FDS_IN(fds, n) (fds->in + n) |
260 | #define FDS_OUT(fds, n) (fds->out + n) | |
261 | #define FDS_EX(fds, n) (fds->ex + n) | |
262 | ||
263 | #define BITS(fds, n) (*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n)) | |
264 | ||
265 | static int max_select_fd(unsigned long n, fd_set_bits *fds) | |
266 | { | |
267 | unsigned long *open_fds; | |
268 | unsigned long set; | |
269 | int max; | |
badf1662 | 270 | struct fdtable *fdt; |
1da177e4 LT |
271 | |
272 | /* handle last in-complete long-word first */ | |
273 | set = ~(~0UL << (n & (__NFDBITS-1))); | |
274 | n /= __NFDBITS; | |
badf1662 DS |
275 | fdt = files_fdtable(current->files); |
276 | open_fds = fdt->open_fds->fds_bits+n; | |
1da177e4 LT |
277 | max = 0; |
278 | if (set) { | |
279 | set &= BITS(fds, n); | |
280 | if (set) { | |
281 | if (!(set & ~*open_fds)) | |
282 | goto get_max; | |
283 | return -EBADF; | |
284 | } | |
285 | } | |
286 | while (n) { | |
287 | open_fds--; | |
288 | n--; | |
289 | set = BITS(fds, n); | |
290 | if (!set) | |
291 | continue; | |
292 | if (set & ~*open_fds) | |
293 | return -EBADF; | |
294 | if (max) | |
295 | continue; | |
296 | get_max: | |
297 | do { | |
298 | max++; | |
299 | set >>= 1; | |
300 | } while (set); | |
301 | max += n * __NFDBITS; | |
302 | } | |
303 | ||
304 | return max; | |
305 | } | |
306 | ||
1da177e4 LT |
307 | #define POLLIN_SET (POLLRDNORM | POLLRDBAND | POLLIN | POLLHUP | POLLERR) |
308 | #define POLLOUT_SET (POLLWRBAND | POLLWRNORM | POLLOUT | POLLERR) | |
309 | #define POLLEX_SET (POLLPRI) | |
310 | ||
8ff3e8e8 | 311 | int do_select(int n, fd_set_bits *fds, struct timespec *end_time) |
1da177e4 | 312 | { |
8ff3e8e8 | 313 | ktime_t expire, *to = NULL; |
1da177e4 LT |
314 | struct poll_wqueues table; |
315 | poll_table *wait; | |
8ff3e8e8 | 316 | int retval, i, timed_out = 0; |
90d6e24a | 317 | unsigned long slack = 0; |
1da177e4 | 318 | |
b835996f | 319 | rcu_read_lock(); |
1da177e4 | 320 | retval = max_select_fd(n, fds); |
b835996f | 321 | rcu_read_unlock(); |
1da177e4 LT |
322 | |
323 | if (retval < 0) | |
324 | return retval; | |
325 | n = retval; | |
326 | ||
327 | poll_initwait(&table); | |
328 | wait = &table.pt; | |
8ff3e8e8 | 329 | if (end_time && !end_time->tv_sec && !end_time->tv_nsec) { |
1da177e4 | 330 | wait = NULL; |
8ff3e8e8 AV |
331 | timed_out = 1; |
332 | } | |
333 | ||
90d6e24a AV |
334 | if (end_time) |
335 | slack = estimate_accuracy(end_time); | |
336 | ||
1da177e4 LT |
337 | retval = 0; |
338 | for (;;) { | |
339 | unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp; | |
340 | ||
341 | set_current_state(TASK_INTERRUPTIBLE); | |
342 | ||
343 | inp = fds->in; outp = fds->out; exp = fds->ex; | |
344 | rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex; | |
345 | ||
346 | for (i = 0; i < n; ++rinp, ++routp, ++rexp) { | |
347 | unsigned long in, out, ex, all_bits, bit = 1, mask, j; | |
348 | unsigned long res_in = 0, res_out = 0, res_ex = 0; | |
99ac48f5 | 349 | const struct file_operations *f_op = NULL; |
1da177e4 LT |
350 | struct file *file = NULL; |
351 | ||
352 | in = *inp++; out = *outp++; ex = *exp++; | |
353 | all_bits = in | out | ex; | |
354 | if (all_bits == 0) { | |
355 | i += __NFDBITS; | |
356 | continue; | |
357 | } | |
358 | ||
359 | for (j = 0; j < __NFDBITS; ++j, ++i, bit <<= 1) { | |
e4a1f129 | 360 | int fput_needed; |
1da177e4 LT |
361 | if (i >= n) |
362 | break; | |
363 | if (!(bit & all_bits)) | |
364 | continue; | |
e4a1f129 | 365 | file = fget_light(i, &fput_needed); |
1da177e4 LT |
366 | if (file) { |
367 | f_op = file->f_op; | |
368 | mask = DEFAULT_POLLMASK; | |
369 | if (f_op && f_op->poll) | |
370 | mask = (*f_op->poll)(file, retval ? NULL : wait); | |
e4a1f129 | 371 | fput_light(file, fput_needed); |
1da177e4 LT |
372 | if ((mask & POLLIN_SET) && (in & bit)) { |
373 | res_in |= bit; | |
374 | retval++; | |
375 | } | |
376 | if ((mask & POLLOUT_SET) && (out & bit)) { | |
377 | res_out |= bit; | |
378 | retval++; | |
379 | } | |
380 | if ((mask & POLLEX_SET) && (ex & bit)) { | |
381 | res_ex |= bit; | |
382 | retval++; | |
383 | } | |
384 | } | |
1da177e4 LT |
385 | } |
386 | if (res_in) | |
387 | *rinp = res_in; | |
388 | if (res_out) | |
389 | *routp = res_out; | |
390 | if (res_ex) | |
391 | *rexp = res_ex; | |
55d85384 | 392 | cond_resched(); |
1da177e4 LT |
393 | } |
394 | wait = NULL; | |
8ff3e8e8 | 395 | if (retval || timed_out || signal_pending(current)) |
1da177e4 | 396 | break; |
f5264481 | 397 | if (table.error) { |
1da177e4 LT |
398 | retval = table.error; |
399 | break; | |
400 | } | |
9f72949f | 401 | |
8ff3e8e8 AV |
402 | /* |
403 | * If this is the first loop and we have a timeout | |
404 | * given, then we convert to ktime_t and set the to | |
405 | * pointer to the expiry value. | |
406 | */ | |
407 | if (end_time && !to) { | |
408 | expire = timespec_to_ktime(*end_time); | |
409 | to = &expire; | |
9f72949f | 410 | } |
8ff3e8e8 | 411 | |
90d6e24a | 412 | if (!schedule_hrtimeout_range(to, slack, HRTIMER_MODE_ABS)) |
8ff3e8e8 | 413 | timed_out = 1; |
1da177e4 LT |
414 | } |
415 | __set_current_state(TASK_RUNNING); | |
416 | ||
417 | poll_freewait(&table); | |
418 | ||
1da177e4 LT |
419 | return retval; |
420 | } | |
421 | ||
1da177e4 LT |
422 | /* |
423 | * We can actually return ERESTARTSYS instead of EINTR, but I'd | |
424 | * like to be certain this leads to no problems. So I return | |
425 | * EINTR just for safety. | |
426 | * | |
427 | * Update: ERESTARTSYS breaks at least the xview clock binary, so | |
428 | * I'm trying ERESTARTNOHAND which restart only when you want to. | |
429 | */ | |
430 | #define MAX_SELECT_SECONDS \ | |
431 | ((unsigned long) (MAX_SCHEDULE_TIMEOUT / HZ)-1) | |
432 | ||
a2dcb44c | 433 | int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp, |
8ff3e8e8 | 434 | fd_set __user *exp, struct timespec *end_time) |
1da177e4 LT |
435 | { |
436 | fd_set_bits fds; | |
29ff2db5 | 437 | void *bits; |
bbea9f69 | 438 | int ret, max_fds; |
b04eb6aa | 439 | unsigned int size; |
badf1662 | 440 | struct fdtable *fdt; |
70674f95 | 441 | /* Allocate small arguments on the stack to save memory and be faster */ |
30c14e40 | 442 | long stack_fds[SELECT_STACK_ALLOC/sizeof(long)]; |
1da177e4 | 443 | |
1da177e4 LT |
444 | ret = -EINVAL; |
445 | if (n < 0) | |
446 | goto out_nofds; | |
447 | ||
bbea9f69 | 448 | /* max_fds can increase, so grab it once to avoid race */ |
b835996f | 449 | rcu_read_lock(); |
badf1662 | 450 | fdt = files_fdtable(current->files); |
bbea9f69 | 451 | max_fds = fdt->max_fds; |
b835996f | 452 | rcu_read_unlock(); |
bbea9f69 VL |
453 | if (n > max_fds) |
454 | n = max_fds; | |
1da177e4 LT |
455 | |
456 | /* | |
457 | * We need 6 bitmaps (in/out/ex for both incoming and outgoing), | |
458 | * since we used fdset we need to allocate memory in units of | |
459 | * long-words. | |
460 | */ | |
1da177e4 | 461 | size = FDS_BYTES(n); |
b04eb6aa MBJ |
462 | bits = stack_fds; |
463 | if (size > sizeof(stack_fds) / 6) { | |
464 | /* Not enough space in on-stack array; must use kmalloc */ | |
465 | ret = -ENOMEM; | |
70674f95 | 466 | bits = kmalloc(6 * size, GFP_KERNEL); |
b04eb6aa MBJ |
467 | if (!bits) |
468 | goto out_nofds; | |
469 | } | |
29ff2db5 AM |
470 | fds.in = bits; |
471 | fds.out = bits + size; | |
472 | fds.ex = bits + 2*size; | |
473 | fds.res_in = bits + 3*size; | |
474 | fds.res_out = bits + 4*size; | |
475 | fds.res_ex = bits + 5*size; | |
1da177e4 LT |
476 | |
477 | if ((ret = get_fd_set(n, inp, fds.in)) || | |
478 | (ret = get_fd_set(n, outp, fds.out)) || | |
479 | (ret = get_fd_set(n, exp, fds.ex))) | |
480 | goto out; | |
481 | zero_fd_set(n, fds.res_in); | |
482 | zero_fd_set(n, fds.res_out); | |
483 | zero_fd_set(n, fds.res_ex); | |
484 | ||
8ff3e8e8 | 485 | ret = do_select(n, &fds, end_time); |
1da177e4 LT |
486 | |
487 | if (ret < 0) | |
488 | goto out; | |
489 | if (!ret) { | |
490 | ret = -ERESTARTNOHAND; | |
491 | if (signal_pending(current)) | |
492 | goto out; | |
493 | ret = 0; | |
494 | } | |
495 | ||
496 | if (set_fd_set(n, inp, fds.res_in) || | |
497 | set_fd_set(n, outp, fds.res_out) || | |
498 | set_fd_set(n, exp, fds.res_ex)) | |
499 | ret = -EFAULT; | |
500 | ||
501 | out: | |
70674f95 AK |
502 | if (bits != stack_fds) |
503 | kfree(bits); | |
1da177e4 LT |
504 | out_nofds: |
505 | return ret; | |
506 | } | |
507 | ||
9f72949f DW |
508 | asmlinkage long sys_select(int n, fd_set __user *inp, fd_set __user *outp, |
509 | fd_set __user *exp, struct timeval __user *tvp) | |
510 | { | |
8ff3e8e8 | 511 | struct timespec end_time, *to = NULL; |
9f72949f DW |
512 | struct timeval tv; |
513 | int ret; | |
514 | ||
515 | if (tvp) { | |
516 | if (copy_from_user(&tv, tvp, sizeof(tv))) | |
517 | return -EFAULT; | |
518 | ||
8ff3e8e8 AV |
519 | to = &end_time; |
520 | if (poll_select_set_timeout(to, tv.tv_sec, | |
521 | tv.tv_usec * NSEC_PER_USEC)) | |
9f72949f | 522 | return -EINVAL; |
9f72949f DW |
523 | } |
524 | ||
8ff3e8e8 AV |
525 | ret = core_sys_select(n, inp, outp, exp, to); |
526 | ret = poll_select_copy_remaining(&end_time, tvp, 1, ret); | |
9f72949f DW |
527 | |
528 | return ret; | |
529 | } | |
530 | ||
f3de272b | 531 | #ifdef HAVE_SET_RESTORE_SIGMASK |
9f72949f DW |
532 | asmlinkage long sys_pselect7(int n, fd_set __user *inp, fd_set __user *outp, |
533 | fd_set __user *exp, struct timespec __user *tsp, | |
534 | const sigset_t __user *sigmask, size_t sigsetsize) | |
535 | { | |
9f72949f | 536 | sigset_t ksigmask, sigsaved; |
8ff3e8e8 | 537 | struct timespec ts, end_time, *to = NULL; |
9f72949f DW |
538 | int ret; |
539 | ||
540 | if (tsp) { | |
541 | if (copy_from_user(&ts, tsp, sizeof(ts))) | |
542 | return -EFAULT; | |
543 | ||
8ff3e8e8 AV |
544 | to = &end_time; |
545 | if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) | |
9f72949f | 546 | return -EINVAL; |
9f72949f DW |
547 | } |
548 | ||
549 | if (sigmask) { | |
550 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
551 | if (sigsetsize != sizeof(sigset_t)) | |
552 | return -EINVAL; | |
553 | if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask))) | |
554 | return -EFAULT; | |
555 | ||
556 | sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
557 | sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); | |
558 | } | |
559 | ||
8ff3e8e8 AV |
560 | ret = core_sys_select(n, inp, outp, exp, &end_time); |
561 | ret = poll_select_copy_remaining(&end_time, tsp, 0, ret); | |
9f72949f DW |
562 | |
563 | if (ret == -ERESTARTNOHAND) { | |
564 | /* | |
565 | * Don't restore the signal mask yet. Let do_signal() deliver | |
566 | * the signal on the way back to userspace, before the signal | |
567 | * mask is restored. | |
568 | */ | |
569 | if (sigmask) { | |
570 | memcpy(¤t->saved_sigmask, &sigsaved, | |
571 | sizeof(sigsaved)); | |
4e4c22c7 | 572 | set_restore_sigmask(); |
9f72949f DW |
573 | } |
574 | } else if (sigmask) | |
575 | sigprocmask(SIG_SETMASK, &sigsaved, NULL); | |
576 | ||
577 | return ret; | |
578 | } | |
579 | ||
580 | /* | |
581 | * Most architectures can't handle 7-argument syscalls. So we provide a | |
582 | * 6-argument version where the sixth argument is a pointer to a structure | |
583 | * which has a pointer to the sigset_t itself followed by a size_t containing | |
584 | * the sigset size. | |
585 | */ | |
586 | asmlinkage long sys_pselect6(int n, fd_set __user *inp, fd_set __user *outp, | |
587 | fd_set __user *exp, struct timespec __user *tsp, void __user *sig) | |
588 | { | |
589 | size_t sigsetsize = 0; | |
590 | sigset_t __user *up = NULL; | |
591 | ||
592 | if (sig) { | |
593 | if (!access_ok(VERIFY_READ, sig, sizeof(void *)+sizeof(size_t)) | |
e110ab94 | 594 | || __get_user(up, (sigset_t __user * __user *)sig) |
9f72949f | 595 | || __get_user(sigsetsize, |
e110ab94 | 596 | (size_t __user *)(sig+sizeof(void *)))) |
9f72949f DW |
597 | return -EFAULT; |
598 | } | |
599 | ||
600 | return sys_pselect7(n, inp, outp, exp, tsp, up, sigsetsize); | |
601 | } | |
f3de272b | 602 | #endif /* HAVE_SET_RESTORE_SIGMASK */ |
9f72949f | 603 | |
1da177e4 LT |
604 | struct poll_list { |
605 | struct poll_list *next; | |
606 | int len; | |
607 | struct pollfd entries[0]; | |
608 | }; | |
609 | ||
610 | #define POLLFD_PER_PAGE ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd)) | |
611 | ||
4a4b69f7 VL |
612 | /* |
613 | * Fish for pollable events on the pollfd->fd file descriptor. We're only | |
614 | * interested in events matching the pollfd->events mask, and the result | |
615 | * matching that mask is both recorded in pollfd->revents and returned. The | |
616 | * pwait poll_table will be used by the fd-provided poll handler for waiting, | |
617 | * if non-NULL. | |
618 | */ | |
619 | static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait) | |
1da177e4 | 620 | { |
4a4b69f7 VL |
621 | unsigned int mask; |
622 | int fd; | |
623 | ||
624 | mask = 0; | |
625 | fd = pollfd->fd; | |
626 | if (fd >= 0) { | |
627 | int fput_needed; | |
628 | struct file * file; | |
629 | ||
630 | file = fget_light(fd, &fput_needed); | |
631 | mask = POLLNVAL; | |
632 | if (file != NULL) { | |
633 | mask = DEFAULT_POLLMASK; | |
634 | if (file->f_op && file->f_op->poll) | |
635 | mask = file->f_op->poll(file, pwait); | |
636 | /* Mask out unneeded events. */ | |
637 | mask &= pollfd->events | POLLERR | POLLHUP; | |
638 | fput_light(file, fput_needed); | |
1da177e4 | 639 | } |
1da177e4 | 640 | } |
4a4b69f7 VL |
641 | pollfd->revents = mask; |
642 | ||
643 | return mask; | |
1da177e4 LT |
644 | } |
645 | ||
646 | static int do_poll(unsigned int nfds, struct poll_list *list, | |
8ff3e8e8 | 647 | struct poll_wqueues *wait, struct timespec *end_time) |
1da177e4 | 648 | { |
1da177e4 | 649 | poll_table* pt = &wait->pt; |
8ff3e8e8 AV |
650 | ktime_t expire, *to = NULL; |
651 | int timed_out = 0, count = 0; | |
90d6e24a | 652 | unsigned long slack = 0; |
1da177e4 | 653 | |
9f72949f | 654 | /* Optimise the no-wait case */ |
8ff3e8e8 | 655 | if (end_time && !end_time->tv_sec && !end_time->tv_nsec) { |
1da177e4 | 656 | pt = NULL; |
8ff3e8e8 AV |
657 | timed_out = 1; |
658 | } | |
9bf084f7 | 659 | |
90d6e24a AV |
660 | if (end_time) |
661 | slack = estimate_accuracy(end_time); | |
662 | ||
1da177e4 LT |
663 | for (;;) { |
664 | struct poll_list *walk; | |
9f72949f | 665 | |
1da177e4 | 666 | set_current_state(TASK_INTERRUPTIBLE); |
4a4b69f7 VL |
667 | for (walk = list; walk != NULL; walk = walk->next) { |
668 | struct pollfd * pfd, * pfd_end; | |
669 | ||
670 | pfd = walk->entries; | |
671 | pfd_end = pfd + walk->len; | |
672 | for (; pfd != pfd_end; pfd++) { | |
673 | /* | |
674 | * Fish for events. If we found one, record it | |
675 | * and kill the poll_table, so we don't | |
676 | * needlessly register any other waiters after | |
677 | * this. They'll get immediately deregistered | |
678 | * when we break out and return. | |
679 | */ | |
680 | if (do_pollfd(pfd, pt)) { | |
681 | count++; | |
682 | pt = NULL; | |
683 | } | |
684 | } | |
1da177e4 | 685 | } |
4a4b69f7 VL |
686 | /* |
687 | * All waiters have already been registered, so don't provide | |
688 | * a poll_table to them on the next loop iteration. | |
689 | */ | |
1da177e4 | 690 | pt = NULL; |
9bf084f7 ON |
691 | if (!count) { |
692 | count = wait->error; | |
693 | if (signal_pending(current)) | |
694 | count = -EINTR; | |
695 | } | |
8ff3e8e8 | 696 | if (count || timed_out) |
1da177e4 | 697 | break; |
9f72949f | 698 | |
8ff3e8e8 AV |
699 | /* |
700 | * If this is the first loop and we have a timeout | |
701 | * given, then we convert to ktime_t and set the to | |
702 | * pointer to the expiry value. | |
703 | */ | |
704 | if (end_time && !to) { | |
705 | expire = timespec_to_ktime(*end_time); | |
706 | to = &expire; | |
9f72949f DW |
707 | } |
708 | ||
90d6e24a | 709 | if (!schedule_hrtimeout_range(to, slack, HRTIMER_MODE_ABS)) |
8ff3e8e8 | 710 | timed_out = 1; |
1da177e4 LT |
711 | } |
712 | __set_current_state(TASK_RUNNING); | |
713 | return count; | |
714 | } | |
715 | ||
70674f95 AK |
716 | #define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \ |
717 | sizeof(struct pollfd)) | |
718 | ||
8ff3e8e8 AV |
719 | int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds, |
720 | struct timespec *end_time) | |
1da177e4 LT |
721 | { |
722 | struct poll_wqueues table; | |
252e5725 | 723 | int err = -EFAULT, fdcount, len, size; |
30c14e40 JS |
724 | /* Allocate small arguments on the stack to save memory and be |
725 | faster - use long to make sure the buffer is aligned properly | |
726 | on 64 bit archs to avoid unaligned access */ | |
727 | long stack_pps[POLL_STACK_ALLOC/sizeof(long)]; | |
252e5725 ON |
728 | struct poll_list *const head = (struct poll_list *)stack_pps; |
729 | struct poll_list *walk = head; | |
730 | unsigned long todo = nfds; | |
1da177e4 | 731 | |
4e6fd33b | 732 | if (nfds > current->signal->rlim[RLIMIT_NOFILE].rlim_cur) |
1da177e4 LT |
733 | return -EINVAL; |
734 | ||
252e5725 ON |
735 | len = min_t(unsigned int, nfds, N_STACK_PPS); |
736 | for (;;) { | |
737 | walk->next = NULL; | |
738 | walk->len = len; | |
739 | if (!len) | |
740 | break; | |
1da177e4 | 741 | |
252e5725 ON |
742 | if (copy_from_user(walk->entries, ufds + nfds-todo, |
743 | sizeof(struct pollfd) * walk->len)) | |
744 | goto out_fds; | |
745 | ||
746 | todo -= walk->len; | |
747 | if (!todo) | |
748 | break; | |
1da177e4 | 749 | |
252e5725 ON |
750 | len = min(todo, POLLFD_PER_PAGE); |
751 | size = sizeof(struct poll_list) + sizeof(struct pollfd) * len; | |
752 | walk = walk->next = kmalloc(size, GFP_KERNEL); | |
753 | if (!walk) { | |
754 | err = -ENOMEM; | |
1da177e4 LT |
755 | goto out_fds; |
756 | } | |
1da177e4 | 757 | } |
9f72949f | 758 | |
252e5725 | 759 | poll_initwait(&table); |
8ff3e8e8 | 760 | fdcount = do_poll(nfds, head, &table, end_time); |
252e5725 | 761 | poll_freewait(&table); |
1da177e4 | 762 | |
252e5725 | 763 | for (walk = head; walk; walk = walk->next) { |
1da177e4 LT |
764 | struct pollfd *fds = walk->entries; |
765 | int j; | |
766 | ||
252e5725 ON |
767 | for (j = 0; j < walk->len; j++, ufds++) |
768 | if (__put_user(fds[j].revents, &ufds->revents)) | |
1da177e4 | 769 | goto out_fds; |
1da177e4 | 770 | } |
252e5725 | 771 | |
1da177e4 | 772 | err = fdcount; |
1da177e4 | 773 | out_fds: |
252e5725 ON |
774 | walk = head->next; |
775 | while (walk) { | |
776 | struct poll_list *pos = walk; | |
777 | walk = walk->next; | |
778 | kfree(pos); | |
1da177e4 | 779 | } |
252e5725 | 780 | |
1da177e4 LT |
781 | return err; |
782 | } | |
9f72949f | 783 | |
3075d9da CW |
784 | static long do_restart_poll(struct restart_block *restart_block) |
785 | { | |
8ff3e8e8 AV |
786 | struct pollfd __user *ufds = restart_block->poll.ufds; |
787 | int nfds = restart_block->poll.nfds; | |
788 | struct timespec *to = NULL, end_time; | |
3075d9da CW |
789 | int ret; |
790 | ||
8ff3e8e8 AV |
791 | if (restart_block->poll.has_timeout) { |
792 | end_time.tv_sec = restart_block->poll.tv_sec; | |
793 | end_time.tv_nsec = restart_block->poll.tv_nsec; | |
794 | to = &end_time; | |
795 | } | |
796 | ||
797 | ret = do_sys_poll(ufds, nfds, to); | |
798 | ||
3075d9da CW |
799 | if (ret == -EINTR) { |
800 | restart_block->fn = do_restart_poll; | |
3075d9da CW |
801 | ret = -ERESTART_RESTARTBLOCK; |
802 | } | |
803 | return ret; | |
804 | } | |
805 | ||
9f72949f DW |
806 | asmlinkage long sys_poll(struct pollfd __user *ufds, unsigned int nfds, |
807 | long timeout_msecs) | |
808 | { | |
8ff3e8e8 | 809 | struct timespec end_time, *to = NULL; |
3075d9da | 810 | int ret; |
9f72949f | 811 | |
8ff3e8e8 AV |
812 | if (timeout_msecs >= 0) { |
813 | to = &end_time; | |
814 | poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC, | |
815 | NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC)); | |
9f72949f DW |
816 | } |
817 | ||
8ff3e8e8 AV |
818 | ret = do_sys_poll(ufds, nfds, to); |
819 | ||
3075d9da CW |
820 | if (ret == -EINTR) { |
821 | struct restart_block *restart_block; | |
8ff3e8e8 | 822 | |
3075d9da CW |
823 | restart_block = ¤t_thread_info()->restart_block; |
824 | restart_block->fn = do_restart_poll; | |
8ff3e8e8 AV |
825 | restart_block->poll.ufds = ufds; |
826 | restart_block->poll.nfds = nfds; | |
827 | ||
828 | if (timeout_msecs >= 0) { | |
829 | restart_block->poll.tv_sec = end_time.tv_sec; | |
830 | restart_block->poll.tv_nsec = end_time.tv_nsec; | |
831 | restart_block->poll.has_timeout = 1; | |
832 | } else | |
833 | restart_block->poll.has_timeout = 0; | |
834 | ||
3075d9da CW |
835 | ret = -ERESTART_RESTARTBLOCK; |
836 | } | |
837 | return ret; | |
9f72949f DW |
838 | } |
839 | ||
f3de272b | 840 | #ifdef HAVE_SET_RESTORE_SIGMASK |
9f72949f DW |
841 | asmlinkage long sys_ppoll(struct pollfd __user *ufds, unsigned int nfds, |
842 | struct timespec __user *tsp, const sigset_t __user *sigmask, | |
843 | size_t sigsetsize) | |
844 | { | |
845 | sigset_t ksigmask, sigsaved; | |
8ff3e8e8 | 846 | struct timespec ts, end_time, *to = NULL; |
9f72949f DW |
847 | int ret; |
848 | ||
849 | if (tsp) { | |
850 | if (copy_from_user(&ts, tsp, sizeof(ts))) | |
851 | return -EFAULT; | |
852 | ||
8ff3e8e8 AV |
853 | to = &end_time; |
854 | if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) | |
855 | return -EINVAL; | |
9f72949f DW |
856 | } |
857 | ||
858 | if (sigmask) { | |
859 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
860 | if (sigsetsize != sizeof(sigset_t)) | |
861 | return -EINVAL; | |
862 | if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask))) | |
863 | return -EFAULT; | |
864 | ||
865 | sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
866 | sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); | |
867 | } | |
868 | ||
8ff3e8e8 | 869 | ret = do_sys_poll(ufds, nfds, to); |
9f72949f DW |
870 | |
871 | /* We can restart this syscall, usually */ | |
872 | if (ret == -EINTR) { | |
873 | /* | |
874 | * Don't restore the signal mask yet. Let do_signal() deliver | |
875 | * the signal on the way back to userspace, before the signal | |
876 | * mask is restored. | |
877 | */ | |
878 | if (sigmask) { | |
879 | memcpy(¤t->saved_sigmask, &sigsaved, | |
880 | sizeof(sigsaved)); | |
4e4c22c7 | 881 | set_restore_sigmask(); |
9f72949f DW |
882 | } |
883 | ret = -ERESTARTNOHAND; | |
884 | } else if (sigmask) | |
885 | sigprocmask(SIG_SETMASK, &sigsaved, NULL); | |
886 | ||
8ff3e8e8 | 887 | ret = poll_select_copy_remaining(&end_time, tsp, 0, ret); |
9f72949f DW |
888 | |
889 | return ret; | |
890 | } | |
f3de272b | 891 | #endif /* HAVE_SET_RESTORE_SIGMASK */ |