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> | |
24 | #include <linux/fs.h> | |
b835996f | 25 | #include <linux/rcupdate.h> |
1da177e4 LT |
26 | |
27 | #include <asm/uaccess.h> | |
28 | ||
1da177e4 LT |
29 | struct poll_table_page { |
30 | struct poll_table_page * next; | |
31 | struct poll_table_entry * entry; | |
32 | struct poll_table_entry entries[0]; | |
33 | }; | |
34 | ||
35 | #define POLL_TABLE_FULL(table) \ | |
36 | ((unsigned long)((table)->entry+1) > PAGE_SIZE + (unsigned long)(table)) | |
37 | ||
38 | /* | |
39 | * Ok, Peter made a complicated, but straightforward multiple_wait() function. | |
40 | * I have rewritten this, taking some shortcuts: This code may not be easy to | |
41 | * follow, but it should be free of race-conditions, and it's practical. If you | |
42 | * understand what I'm doing here, then you understand how the linux | |
43 | * sleep/wakeup mechanism works. | |
44 | * | |
45 | * Two very simple procedures, poll_wait() and poll_freewait() make all the | |
46 | * work. poll_wait() is an inline-function defined in <linux/poll.h>, | |
47 | * as all select/poll functions have to call it to add an entry to the | |
48 | * poll table. | |
49 | */ | |
75c96f85 AB |
50 | static void __pollwait(struct file *filp, wait_queue_head_t *wait_address, |
51 | poll_table *p); | |
1da177e4 LT |
52 | |
53 | void poll_initwait(struct poll_wqueues *pwq) | |
54 | { | |
55 | init_poll_funcptr(&pwq->pt, __pollwait); | |
56 | pwq->error = 0; | |
57 | pwq->table = NULL; | |
70674f95 | 58 | pwq->inline_index = 0; |
1da177e4 LT |
59 | } |
60 | ||
61 | EXPORT_SYMBOL(poll_initwait); | |
62 | ||
70674f95 AK |
63 | static void free_poll_entry(struct poll_table_entry *entry) |
64 | { | |
ccf6780d | 65 | remove_wait_queue(entry->wait_address, &entry->wait); |
70674f95 AK |
66 | fput(entry->filp); |
67 | } | |
68 | ||
1da177e4 LT |
69 | void poll_freewait(struct poll_wqueues *pwq) |
70 | { | |
71 | struct poll_table_page * p = pwq->table; | |
70674f95 AK |
72 | int i; |
73 | for (i = 0; i < pwq->inline_index; i++) | |
74 | free_poll_entry(pwq->inline_entries + i); | |
1da177e4 LT |
75 | while (p) { |
76 | struct poll_table_entry * entry; | |
77 | struct poll_table_page *old; | |
78 | ||
79 | entry = p->entry; | |
80 | do { | |
81 | entry--; | |
70674f95 | 82 | free_poll_entry(entry); |
1da177e4 LT |
83 | } while (entry > p->entries); |
84 | old = p; | |
85 | p = p->next; | |
86 | free_page((unsigned long) old); | |
87 | } | |
88 | } | |
89 | ||
90 | EXPORT_SYMBOL(poll_freewait); | |
91 | ||
70674f95 | 92 | static struct poll_table_entry *poll_get_entry(poll_table *_p) |
1da177e4 LT |
93 | { |
94 | struct poll_wqueues *p = container_of(_p, struct poll_wqueues, pt); | |
95 | struct poll_table_page *table = p->table; | |
96 | ||
70674f95 AK |
97 | if (p->inline_index < N_INLINE_POLL_ENTRIES) |
98 | return p->inline_entries + p->inline_index++; | |
99 | ||
1da177e4 LT |
100 | if (!table || POLL_TABLE_FULL(table)) { |
101 | struct poll_table_page *new_table; | |
102 | ||
103 | new_table = (struct poll_table_page *) __get_free_page(GFP_KERNEL); | |
104 | if (!new_table) { | |
105 | p->error = -ENOMEM; | |
106 | __set_current_state(TASK_RUNNING); | |
70674f95 | 107 | return NULL; |
1da177e4 LT |
108 | } |
109 | new_table->entry = new_table->entries; | |
110 | new_table->next = table; | |
111 | p->table = new_table; | |
112 | table = new_table; | |
113 | } | |
114 | ||
70674f95 AK |
115 | return table->entry++; |
116 | } | |
117 | ||
118 | /* Add a new entry */ | |
119 | static void __pollwait(struct file *filp, wait_queue_head_t *wait_address, | |
120 | poll_table *p) | |
121 | { | |
122 | struct poll_table_entry *entry = poll_get_entry(p); | |
123 | if (!entry) | |
124 | return; | |
125 | get_file(filp); | |
126 | entry->filp = filp; | |
127 | entry->wait_address = wait_address; | |
128 | init_waitqueue_entry(&entry->wait, current); | |
ccf6780d | 129 | add_wait_queue(wait_address, &entry->wait); |
1da177e4 LT |
130 | } |
131 | ||
132 | #define FDS_IN(fds, n) (fds->in + n) | |
133 | #define FDS_OUT(fds, n) (fds->out + n) | |
134 | #define FDS_EX(fds, n) (fds->ex + n) | |
135 | ||
136 | #define BITS(fds, n) (*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n)) | |
137 | ||
138 | static int max_select_fd(unsigned long n, fd_set_bits *fds) | |
139 | { | |
140 | unsigned long *open_fds; | |
141 | unsigned long set; | |
142 | int max; | |
badf1662 | 143 | struct fdtable *fdt; |
1da177e4 LT |
144 | |
145 | /* handle last in-complete long-word first */ | |
146 | set = ~(~0UL << (n & (__NFDBITS-1))); | |
147 | n /= __NFDBITS; | |
badf1662 DS |
148 | fdt = files_fdtable(current->files); |
149 | open_fds = fdt->open_fds->fds_bits+n; | |
1da177e4 LT |
150 | max = 0; |
151 | if (set) { | |
152 | set &= BITS(fds, n); | |
153 | if (set) { | |
154 | if (!(set & ~*open_fds)) | |
155 | goto get_max; | |
156 | return -EBADF; | |
157 | } | |
158 | } | |
159 | while (n) { | |
160 | open_fds--; | |
161 | n--; | |
162 | set = BITS(fds, n); | |
163 | if (!set) | |
164 | continue; | |
165 | if (set & ~*open_fds) | |
166 | return -EBADF; | |
167 | if (max) | |
168 | continue; | |
169 | get_max: | |
170 | do { | |
171 | max++; | |
172 | set >>= 1; | |
173 | } while (set); | |
174 | max += n * __NFDBITS; | |
175 | } | |
176 | ||
177 | return max; | |
178 | } | |
179 | ||
180 | #define BIT(i) (1UL << ((i)&(__NFDBITS-1))) | |
181 | #define MEM(i,m) ((m)+(unsigned)(i)/__NFDBITS) | |
182 | #define ISSET(i,m) (((i)&*(m)) != 0) | |
183 | #define SET(i,m) (*(m) |= (i)) | |
184 | ||
185 | #define POLLIN_SET (POLLRDNORM | POLLRDBAND | POLLIN | POLLHUP | POLLERR) | |
186 | #define POLLOUT_SET (POLLWRBAND | POLLWRNORM | POLLOUT | POLLERR) | |
187 | #define POLLEX_SET (POLLPRI) | |
188 | ||
9f72949f | 189 | int do_select(int n, fd_set_bits *fds, s64 *timeout) |
1da177e4 LT |
190 | { |
191 | struct poll_wqueues table; | |
192 | poll_table *wait; | |
193 | int retval, i; | |
1da177e4 | 194 | |
b835996f | 195 | rcu_read_lock(); |
1da177e4 | 196 | retval = max_select_fd(n, fds); |
b835996f | 197 | rcu_read_unlock(); |
1da177e4 LT |
198 | |
199 | if (retval < 0) | |
200 | return retval; | |
201 | n = retval; | |
202 | ||
203 | poll_initwait(&table); | |
204 | wait = &table.pt; | |
9f72949f | 205 | if (!*timeout) |
1da177e4 LT |
206 | wait = NULL; |
207 | retval = 0; | |
208 | for (;;) { | |
209 | unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp; | |
9f72949f | 210 | long __timeout; |
1da177e4 LT |
211 | |
212 | set_current_state(TASK_INTERRUPTIBLE); | |
213 | ||
214 | inp = fds->in; outp = fds->out; exp = fds->ex; | |
215 | rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex; | |
216 | ||
217 | for (i = 0; i < n; ++rinp, ++routp, ++rexp) { | |
218 | unsigned long in, out, ex, all_bits, bit = 1, mask, j; | |
219 | unsigned long res_in = 0, res_out = 0, res_ex = 0; | |
99ac48f5 | 220 | const struct file_operations *f_op = NULL; |
1da177e4 LT |
221 | struct file *file = NULL; |
222 | ||
223 | in = *inp++; out = *outp++; ex = *exp++; | |
224 | all_bits = in | out | ex; | |
225 | if (all_bits == 0) { | |
226 | i += __NFDBITS; | |
227 | continue; | |
228 | } | |
229 | ||
230 | for (j = 0; j < __NFDBITS; ++j, ++i, bit <<= 1) { | |
e4a1f129 | 231 | int fput_needed; |
1da177e4 LT |
232 | if (i >= n) |
233 | break; | |
234 | if (!(bit & all_bits)) | |
235 | continue; | |
e4a1f129 | 236 | file = fget_light(i, &fput_needed); |
1da177e4 LT |
237 | if (file) { |
238 | f_op = file->f_op; | |
239 | mask = DEFAULT_POLLMASK; | |
240 | if (f_op && f_op->poll) | |
241 | mask = (*f_op->poll)(file, retval ? NULL : wait); | |
e4a1f129 | 242 | fput_light(file, fput_needed); |
1da177e4 LT |
243 | if ((mask & POLLIN_SET) && (in & bit)) { |
244 | res_in |= bit; | |
245 | retval++; | |
246 | } | |
247 | if ((mask & POLLOUT_SET) && (out & bit)) { | |
248 | res_out |= bit; | |
249 | retval++; | |
250 | } | |
251 | if ((mask & POLLEX_SET) && (ex & bit)) { | |
252 | res_ex |= bit; | |
253 | retval++; | |
254 | } | |
255 | } | |
256 | cond_resched(); | |
257 | } | |
258 | if (res_in) | |
259 | *rinp = res_in; | |
260 | if (res_out) | |
261 | *routp = res_out; | |
262 | if (res_ex) | |
263 | *rexp = res_ex; | |
264 | } | |
265 | wait = NULL; | |
9f72949f | 266 | if (retval || !*timeout || signal_pending(current)) |
1da177e4 LT |
267 | break; |
268 | if(table.error) { | |
269 | retval = table.error; | |
270 | break; | |
271 | } | |
9f72949f DW |
272 | |
273 | if (*timeout < 0) { | |
274 | /* Wait indefinitely */ | |
275 | __timeout = MAX_SCHEDULE_TIMEOUT; | |
276 | } else if (unlikely(*timeout >= (s64)MAX_SCHEDULE_TIMEOUT - 1)) { | |
277 | /* Wait for longer than MAX_SCHEDULE_TIMEOUT. Do it in a loop */ | |
278 | __timeout = MAX_SCHEDULE_TIMEOUT - 1; | |
279 | *timeout -= __timeout; | |
280 | } else { | |
281 | __timeout = *timeout; | |
282 | *timeout = 0; | |
283 | } | |
1da177e4 | 284 | __timeout = schedule_timeout(__timeout); |
9f72949f DW |
285 | if (*timeout >= 0) |
286 | *timeout += __timeout; | |
1da177e4 LT |
287 | } |
288 | __set_current_state(TASK_RUNNING); | |
289 | ||
290 | poll_freewait(&table); | |
291 | ||
1da177e4 LT |
292 | return retval; |
293 | } | |
294 | ||
1da177e4 LT |
295 | /* |
296 | * We can actually return ERESTARTSYS instead of EINTR, but I'd | |
297 | * like to be certain this leads to no problems. So I return | |
298 | * EINTR just for safety. | |
299 | * | |
300 | * Update: ERESTARTSYS breaks at least the xview clock binary, so | |
301 | * I'm trying ERESTARTNOHAND which restart only when you want to. | |
302 | */ | |
303 | #define MAX_SELECT_SECONDS \ | |
304 | ((unsigned long) (MAX_SCHEDULE_TIMEOUT / HZ)-1) | |
305 | ||
9f72949f DW |
306 | static int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp, |
307 | fd_set __user *exp, s64 *timeout) | |
1da177e4 LT |
308 | { |
309 | fd_set_bits fds; | |
29ff2db5 | 310 | void *bits; |
bbea9f69 | 311 | int ret, max_fds; |
b04eb6aa | 312 | unsigned int size; |
badf1662 | 313 | struct fdtable *fdt; |
70674f95 | 314 | /* Allocate small arguments on the stack to save memory and be faster */ |
30c14e40 | 315 | long stack_fds[SELECT_STACK_ALLOC/sizeof(long)]; |
1da177e4 | 316 | |
1da177e4 LT |
317 | ret = -EINVAL; |
318 | if (n < 0) | |
319 | goto out_nofds; | |
320 | ||
bbea9f69 | 321 | /* max_fds can increase, so grab it once to avoid race */ |
b835996f | 322 | rcu_read_lock(); |
badf1662 | 323 | fdt = files_fdtable(current->files); |
bbea9f69 | 324 | max_fds = fdt->max_fds; |
b835996f | 325 | rcu_read_unlock(); |
bbea9f69 VL |
326 | if (n > max_fds) |
327 | n = max_fds; | |
1da177e4 LT |
328 | |
329 | /* | |
330 | * We need 6 bitmaps (in/out/ex for both incoming and outgoing), | |
331 | * since we used fdset we need to allocate memory in units of | |
332 | * long-words. | |
333 | */ | |
1da177e4 | 334 | size = FDS_BYTES(n); |
b04eb6aa MBJ |
335 | bits = stack_fds; |
336 | if (size > sizeof(stack_fds) / 6) { | |
337 | /* Not enough space in on-stack array; must use kmalloc */ | |
338 | ret = -ENOMEM; | |
70674f95 | 339 | bits = kmalloc(6 * size, GFP_KERNEL); |
b04eb6aa MBJ |
340 | if (!bits) |
341 | goto out_nofds; | |
342 | } | |
29ff2db5 AM |
343 | fds.in = bits; |
344 | fds.out = bits + size; | |
345 | fds.ex = bits + 2*size; | |
346 | fds.res_in = bits + 3*size; | |
347 | fds.res_out = bits + 4*size; | |
348 | fds.res_ex = bits + 5*size; | |
1da177e4 LT |
349 | |
350 | if ((ret = get_fd_set(n, inp, fds.in)) || | |
351 | (ret = get_fd_set(n, outp, fds.out)) || | |
352 | (ret = get_fd_set(n, exp, fds.ex))) | |
353 | goto out; | |
354 | zero_fd_set(n, fds.res_in); | |
355 | zero_fd_set(n, fds.res_out); | |
356 | zero_fd_set(n, fds.res_ex); | |
357 | ||
9f72949f | 358 | ret = do_select(n, &fds, timeout); |
1da177e4 LT |
359 | |
360 | if (ret < 0) | |
361 | goto out; | |
362 | if (!ret) { | |
363 | ret = -ERESTARTNOHAND; | |
364 | if (signal_pending(current)) | |
365 | goto out; | |
366 | ret = 0; | |
367 | } | |
368 | ||
369 | if (set_fd_set(n, inp, fds.res_in) || | |
370 | set_fd_set(n, outp, fds.res_out) || | |
371 | set_fd_set(n, exp, fds.res_ex)) | |
372 | ret = -EFAULT; | |
373 | ||
374 | out: | |
70674f95 AK |
375 | if (bits != stack_fds) |
376 | kfree(bits); | |
1da177e4 LT |
377 | out_nofds: |
378 | return ret; | |
379 | } | |
380 | ||
9f72949f DW |
381 | asmlinkage long sys_select(int n, fd_set __user *inp, fd_set __user *outp, |
382 | fd_set __user *exp, struct timeval __user *tvp) | |
383 | { | |
384 | s64 timeout = -1; | |
385 | struct timeval tv; | |
386 | int ret; | |
387 | ||
388 | if (tvp) { | |
389 | if (copy_from_user(&tv, tvp, sizeof(tv))) | |
390 | return -EFAULT; | |
391 | ||
392 | if (tv.tv_sec < 0 || tv.tv_usec < 0) | |
393 | return -EINVAL; | |
394 | ||
395 | /* Cast to u64 to make GCC stop complaining */ | |
396 | if ((u64)tv.tv_sec >= (u64)MAX_INT64_SECONDS) | |
397 | timeout = -1; /* infinite */ | |
398 | else { | |
022a1692 | 399 | timeout = DIV_ROUND_UP(tv.tv_usec, USEC_PER_SEC/HZ); |
9f72949f DW |
400 | timeout += tv.tv_sec * HZ; |
401 | } | |
402 | } | |
403 | ||
404 | ret = core_sys_select(n, inp, outp, exp, &timeout); | |
405 | ||
406 | if (tvp) { | |
643a6545 AM |
407 | struct timeval rtv; |
408 | ||
9f72949f DW |
409 | if (current->personality & STICKY_TIMEOUTS) |
410 | goto sticky; | |
643a6545 AM |
411 | rtv.tv_usec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)); |
412 | rtv.tv_sec = timeout; | |
74910e6c | 413 | if (timeval_compare(&rtv, &tv) >= 0) |
643a6545 AM |
414 | rtv = tv; |
415 | if (copy_to_user(tvp, &rtv, sizeof(rtv))) { | |
9f72949f DW |
416 | sticky: |
417 | /* | |
418 | * If an application puts its timeval in read-only | |
419 | * memory, we don't want the Linux-specific update to | |
420 | * the timeval to cause a fault after the select has | |
421 | * completed successfully. However, because we're not | |
422 | * updating the timeval, we can't restart the system | |
423 | * call. | |
424 | */ | |
425 | if (ret == -ERESTARTNOHAND) | |
426 | ret = -EINTR; | |
427 | } | |
428 | } | |
429 | ||
430 | return ret; | |
431 | } | |
432 | ||
433 | #ifdef TIF_RESTORE_SIGMASK | |
434 | asmlinkage long sys_pselect7(int n, fd_set __user *inp, fd_set __user *outp, | |
435 | fd_set __user *exp, struct timespec __user *tsp, | |
436 | const sigset_t __user *sigmask, size_t sigsetsize) | |
437 | { | |
438 | s64 timeout = MAX_SCHEDULE_TIMEOUT; | |
439 | sigset_t ksigmask, sigsaved; | |
440 | struct timespec ts; | |
441 | int ret; | |
442 | ||
443 | if (tsp) { | |
444 | if (copy_from_user(&ts, tsp, sizeof(ts))) | |
445 | return -EFAULT; | |
446 | ||
447 | if (ts.tv_sec < 0 || ts.tv_nsec < 0) | |
448 | return -EINVAL; | |
449 | ||
450 | /* Cast to u64 to make GCC stop complaining */ | |
451 | if ((u64)ts.tv_sec >= (u64)MAX_INT64_SECONDS) | |
452 | timeout = -1; /* infinite */ | |
453 | else { | |
022a1692 | 454 | timeout = DIV_ROUND_UP(ts.tv_nsec, NSEC_PER_SEC/HZ); |
9f72949f DW |
455 | timeout += ts.tv_sec * HZ; |
456 | } | |
457 | } | |
458 | ||
459 | if (sigmask) { | |
460 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
461 | if (sigsetsize != sizeof(sigset_t)) | |
462 | return -EINVAL; | |
463 | if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask))) | |
464 | return -EFAULT; | |
465 | ||
466 | sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
467 | sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); | |
468 | } | |
469 | ||
470 | ret = core_sys_select(n, inp, outp, exp, &timeout); | |
471 | ||
472 | if (tsp) { | |
643a6545 AM |
473 | struct timespec rts; |
474 | ||
9f72949f DW |
475 | if (current->personality & STICKY_TIMEOUTS) |
476 | goto sticky; | |
643a6545 AM |
477 | rts.tv_nsec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)) * |
478 | 1000; | |
479 | rts.tv_sec = timeout; | |
74910e6c | 480 | if (timespec_compare(&rts, &ts) >= 0) |
643a6545 AM |
481 | rts = ts; |
482 | if (copy_to_user(tsp, &rts, sizeof(rts))) { | |
9f72949f DW |
483 | sticky: |
484 | /* | |
485 | * If an application puts its timeval in read-only | |
486 | * memory, we don't want the Linux-specific update to | |
487 | * the timeval to cause a fault after the select has | |
488 | * completed successfully. However, because we're not | |
489 | * updating the timeval, we can't restart the system | |
490 | * call. | |
491 | */ | |
492 | if (ret == -ERESTARTNOHAND) | |
493 | ret = -EINTR; | |
494 | } | |
495 | } | |
496 | ||
497 | if (ret == -ERESTARTNOHAND) { | |
498 | /* | |
499 | * Don't restore the signal mask yet. Let do_signal() deliver | |
500 | * the signal on the way back to userspace, before the signal | |
501 | * mask is restored. | |
502 | */ | |
503 | if (sigmask) { | |
504 | memcpy(¤t->saved_sigmask, &sigsaved, | |
505 | sizeof(sigsaved)); | |
506 | set_thread_flag(TIF_RESTORE_SIGMASK); | |
507 | } | |
508 | } else if (sigmask) | |
509 | sigprocmask(SIG_SETMASK, &sigsaved, NULL); | |
510 | ||
511 | return ret; | |
512 | } | |
513 | ||
514 | /* | |
515 | * Most architectures can't handle 7-argument syscalls. So we provide a | |
516 | * 6-argument version where the sixth argument is a pointer to a structure | |
517 | * which has a pointer to the sigset_t itself followed by a size_t containing | |
518 | * the sigset size. | |
519 | */ | |
520 | asmlinkage long sys_pselect6(int n, fd_set __user *inp, fd_set __user *outp, | |
521 | fd_set __user *exp, struct timespec __user *tsp, void __user *sig) | |
522 | { | |
523 | size_t sigsetsize = 0; | |
524 | sigset_t __user *up = NULL; | |
525 | ||
526 | if (sig) { | |
527 | if (!access_ok(VERIFY_READ, sig, sizeof(void *)+sizeof(size_t)) | |
e110ab94 | 528 | || __get_user(up, (sigset_t __user * __user *)sig) |
9f72949f | 529 | || __get_user(sigsetsize, |
e110ab94 | 530 | (size_t __user *)(sig+sizeof(void *)))) |
9f72949f DW |
531 | return -EFAULT; |
532 | } | |
533 | ||
534 | return sys_pselect7(n, inp, outp, exp, tsp, up, sigsetsize); | |
535 | } | |
536 | #endif /* TIF_RESTORE_SIGMASK */ | |
537 | ||
1da177e4 LT |
538 | struct poll_list { |
539 | struct poll_list *next; | |
540 | int len; | |
541 | struct pollfd entries[0]; | |
542 | }; | |
543 | ||
544 | #define POLLFD_PER_PAGE ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd)) | |
545 | ||
4a4b69f7 VL |
546 | /* |
547 | * Fish for pollable events on the pollfd->fd file descriptor. We're only | |
548 | * interested in events matching the pollfd->events mask, and the result | |
549 | * matching that mask is both recorded in pollfd->revents and returned. The | |
550 | * pwait poll_table will be used by the fd-provided poll handler for waiting, | |
551 | * if non-NULL. | |
552 | */ | |
553 | static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait) | |
1da177e4 | 554 | { |
4a4b69f7 VL |
555 | unsigned int mask; |
556 | int fd; | |
557 | ||
558 | mask = 0; | |
559 | fd = pollfd->fd; | |
560 | if (fd >= 0) { | |
561 | int fput_needed; | |
562 | struct file * file; | |
563 | ||
564 | file = fget_light(fd, &fput_needed); | |
565 | mask = POLLNVAL; | |
566 | if (file != NULL) { | |
567 | mask = DEFAULT_POLLMASK; | |
568 | if (file->f_op && file->f_op->poll) | |
569 | mask = file->f_op->poll(file, pwait); | |
570 | /* Mask out unneeded events. */ | |
571 | mask &= pollfd->events | POLLERR | POLLHUP; | |
572 | fput_light(file, fput_needed); | |
1da177e4 | 573 | } |
1da177e4 | 574 | } |
4a4b69f7 VL |
575 | pollfd->revents = mask; |
576 | ||
577 | return mask; | |
1da177e4 LT |
578 | } |
579 | ||
580 | static int do_poll(unsigned int nfds, struct poll_list *list, | |
9f72949f | 581 | struct poll_wqueues *wait, s64 *timeout) |
1da177e4 LT |
582 | { |
583 | int count = 0; | |
584 | poll_table* pt = &wait->pt; | |
585 | ||
9f72949f DW |
586 | /* Optimise the no-wait case */ |
587 | if (!(*timeout)) | |
1da177e4 | 588 | pt = NULL; |
9bf084f7 | 589 | |
1da177e4 LT |
590 | for (;;) { |
591 | struct poll_list *walk; | |
9f72949f DW |
592 | long __timeout; |
593 | ||
1da177e4 | 594 | set_current_state(TASK_INTERRUPTIBLE); |
4a4b69f7 VL |
595 | for (walk = list; walk != NULL; walk = walk->next) { |
596 | struct pollfd * pfd, * pfd_end; | |
597 | ||
598 | pfd = walk->entries; | |
599 | pfd_end = pfd + walk->len; | |
600 | for (; pfd != pfd_end; pfd++) { | |
601 | /* | |
602 | * Fish for events. If we found one, record it | |
603 | * and kill the poll_table, so we don't | |
604 | * needlessly register any other waiters after | |
605 | * this. They'll get immediately deregistered | |
606 | * when we break out and return. | |
607 | */ | |
608 | if (do_pollfd(pfd, pt)) { | |
609 | count++; | |
610 | pt = NULL; | |
611 | } | |
612 | } | |
1da177e4 | 613 | } |
4a4b69f7 VL |
614 | /* |
615 | * All waiters have already been registered, so don't provide | |
616 | * a poll_table to them on the next loop iteration. | |
617 | */ | |
1da177e4 | 618 | pt = NULL; |
9bf084f7 ON |
619 | if (!count) { |
620 | count = wait->error; | |
621 | if (signal_pending(current)) | |
622 | count = -EINTR; | |
623 | } | |
624 | if (count || !*timeout) | |
1da177e4 | 625 | break; |
9f72949f DW |
626 | |
627 | if (*timeout < 0) { | |
628 | /* Wait indefinitely */ | |
629 | __timeout = MAX_SCHEDULE_TIMEOUT; | |
630 | } else if (unlikely(*timeout >= (s64)MAX_SCHEDULE_TIMEOUT-1)) { | |
631 | /* | |
632 | * Wait for longer than MAX_SCHEDULE_TIMEOUT. Do it in | |
633 | * a loop | |
634 | */ | |
635 | __timeout = MAX_SCHEDULE_TIMEOUT - 1; | |
636 | *timeout -= __timeout; | |
637 | } else { | |
638 | __timeout = *timeout; | |
639 | *timeout = 0; | |
640 | } | |
641 | ||
642 | __timeout = schedule_timeout(__timeout); | |
643 | if (*timeout >= 0) | |
644 | *timeout += __timeout; | |
1da177e4 LT |
645 | } |
646 | __set_current_state(TASK_RUNNING); | |
647 | return count; | |
648 | } | |
649 | ||
70674f95 AK |
650 | #define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \ |
651 | sizeof(struct pollfd)) | |
652 | ||
9f72949f | 653 | int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds, s64 *timeout) |
1da177e4 LT |
654 | { |
655 | struct poll_wqueues table; | |
252e5725 | 656 | int err = -EFAULT, fdcount, len, size; |
30c14e40 JS |
657 | /* Allocate small arguments on the stack to save memory and be |
658 | faster - use long to make sure the buffer is aligned properly | |
659 | on 64 bit archs to avoid unaligned access */ | |
660 | long stack_pps[POLL_STACK_ALLOC/sizeof(long)]; | |
252e5725 ON |
661 | struct poll_list *const head = (struct poll_list *)stack_pps; |
662 | struct poll_list *walk = head; | |
663 | unsigned long todo = nfds; | |
1da177e4 | 664 | |
4e6fd33b | 665 | if (nfds > current->signal->rlim[RLIMIT_NOFILE].rlim_cur) |
1da177e4 LT |
666 | return -EINVAL; |
667 | ||
252e5725 ON |
668 | len = min_t(unsigned int, nfds, N_STACK_PPS); |
669 | for (;;) { | |
670 | walk->next = NULL; | |
671 | walk->len = len; | |
672 | if (!len) | |
673 | break; | |
1da177e4 | 674 | |
252e5725 ON |
675 | if (copy_from_user(walk->entries, ufds + nfds-todo, |
676 | sizeof(struct pollfd) * walk->len)) | |
677 | goto out_fds; | |
678 | ||
679 | todo -= walk->len; | |
680 | if (!todo) | |
681 | break; | |
1da177e4 | 682 | |
252e5725 ON |
683 | len = min(todo, POLLFD_PER_PAGE); |
684 | size = sizeof(struct poll_list) + sizeof(struct pollfd) * len; | |
685 | walk = walk->next = kmalloc(size, GFP_KERNEL); | |
686 | if (!walk) { | |
687 | err = -ENOMEM; | |
1da177e4 LT |
688 | goto out_fds; |
689 | } | |
1da177e4 | 690 | } |
9f72949f | 691 | |
252e5725 | 692 | poll_initwait(&table); |
1da177e4 | 693 | fdcount = do_poll(nfds, head, &table, timeout); |
252e5725 | 694 | poll_freewait(&table); |
1da177e4 | 695 | |
252e5725 | 696 | for (walk = head; walk; walk = walk->next) { |
1da177e4 LT |
697 | struct pollfd *fds = walk->entries; |
698 | int j; | |
699 | ||
252e5725 ON |
700 | for (j = 0; j < walk->len; j++, ufds++) |
701 | if (__put_user(fds[j].revents, &ufds->revents)) | |
1da177e4 | 702 | goto out_fds; |
1da177e4 | 703 | } |
252e5725 | 704 | |
1da177e4 | 705 | err = fdcount; |
1da177e4 | 706 | out_fds: |
252e5725 ON |
707 | walk = head->next; |
708 | while (walk) { | |
709 | struct poll_list *pos = walk; | |
710 | walk = walk->next; | |
711 | kfree(pos); | |
1da177e4 | 712 | } |
252e5725 | 713 | |
1da177e4 LT |
714 | return err; |
715 | } | |
9f72949f | 716 | |
3075d9da CW |
717 | static long do_restart_poll(struct restart_block *restart_block) |
718 | { | |
719 | struct pollfd __user *ufds = (struct pollfd __user*)restart_block->arg0; | |
720 | int nfds = restart_block->arg1; | |
721 | s64 timeout = ((s64)restart_block->arg3<<32) | (s64)restart_block->arg2; | |
722 | int ret; | |
723 | ||
724 | ret = do_sys_poll(ufds, nfds, &timeout); | |
725 | if (ret == -EINTR) { | |
726 | restart_block->fn = do_restart_poll; | |
727 | restart_block->arg2 = timeout & 0xFFFFFFFF; | |
728 | restart_block->arg3 = (u64)timeout >> 32; | |
729 | ret = -ERESTART_RESTARTBLOCK; | |
730 | } | |
731 | return ret; | |
732 | } | |
733 | ||
9f72949f DW |
734 | asmlinkage long sys_poll(struct pollfd __user *ufds, unsigned int nfds, |
735 | long timeout_msecs) | |
736 | { | |
04a3446c | 737 | s64 timeout_jiffies; |
3075d9da | 738 | int ret; |
9f72949f | 739 | |
04a3446c | 740 | if (timeout_msecs > 0) { |
9f72949f DW |
741 | #if HZ > 1000 |
742 | /* We can only overflow if HZ > 1000 */ | |
743 | if (timeout_msecs / 1000 > (s64)0x7fffffffffffffffULL / (s64)HZ) | |
744 | timeout_jiffies = -1; | |
745 | else | |
746 | #endif | |
747 | timeout_jiffies = msecs_to_jiffies(timeout_msecs); | |
04a3446c FI |
748 | } else { |
749 | /* Infinite (< 0) or no (0) timeout */ | |
750 | timeout_jiffies = timeout_msecs; | |
9f72949f DW |
751 | } |
752 | ||
3075d9da CW |
753 | ret = do_sys_poll(ufds, nfds, &timeout_jiffies); |
754 | if (ret == -EINTR) { | |
755 | struct restart_block *restart_block; | |
756 | restart_block = ¤t_thread_info()->restart_block; | |
757 | restart_block->fn = do_restart_poll; | |
758 | restart_block->arg0 = (unsigned long)ufds; | |
759 | restart_block->arg1 = nfds; | |
760 | restart_block->arg2 = timeout_jiffies & 0xFFFFFFFF; | |
761 | restart_block->arg3 = (u64)timeout_jiffies >> 32; | |
762 | ret = -ERESTART_RESTARTBLOCK; | |
763 | } | |
764 | return ret; | |
9f72949f DW |
765 | } |
766 | ||
767 | #ifdef TIF_RESTORE_SIGMASK | |
768 | asmlinkage long sys_ppoll(struct pollfd __user *ufds, unsigned int nfds, | |
769 | struct timespec __user *tsp, const sigset_t __user *sigmask, | |
770 | size_t sigsetsize) | |
771 | { | |
772 | sigset_t ksigmask, sigsaved; | |
773 | struct timespec ts; | |
774 | s64 timeout = -1; | |
775 | int ret; | |
776 | ||
777 | if (tsp) { | |
778 | if (copy_from_user(&ts, tsp, sizeof(ts))) | |
779 | return -EFAULT; | |
780 | ||
781 | /* Cast to u64 to make GCC stop complaining */ | |
782 | if ((u64)ts.tv_sec >= (u64)MAX_INT64_SECONDS) | |
783 | timeout = -1; /* infinite */ | |
784 | else { | |
022a1692 | 785 | timeout = DIV_ROUND_UP(ts.tv_nsec, NSEC_PER_SEC/HZ); |
9f72949f DW |
786 | timeout += ts.tv_sec * HZ; |
787 | } | |
788 | } | |
789 | ||
790 | if (sigmask) { | |
791 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
792 | if (sigsetsize != sizeof(sigset_t)) | |
793 | return -EINVAL; | |
794 | if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask))) | |
795 | return -EFAULT; | |
796 | ||
797 | sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
798 | sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); | |
799 | } | |
800 | ||
801 | ret = do_sys_poll(ufds, nfds, &timeout); | |
802 | ||
803 | /* We can restart this syscall, usually */ | |
804 | if (ret == -EINTR) { | |
805 | /* | |
806 | * Don't restore the signal mask yet. Let do_signal() deliver | |
807 | * the signal on the way back to userspace, before the signal | |
808 | * mask is restored. | |
809 | */ | |
810 | if (sigmask) { | |
811 | memcpy(¤t->saved_sigmask, &sigsaved, | |
812 | sizeof(sigsaved)); | |
813 | set_thread_flag(TIF_RESTORE_SIGMASK); | |
814 | } | |
815 | ret = -ERESTARTNOHAND; | |
816 | } else if (sigmask) | |
817 | sigprocmask(SIG_SETMASK, &sigsaved, NULL); | |
818 | ||
819 | if (tsp && timeout >= 0) { | |
643a6545 AM |
820 | struct timespec rts; |
821 | ||
9f72949f DW |
822 | if (current->personality & STICKY_TIMEOUTS) |
823 | goto sticky; | |
824 | /* Yes, we know it's actually an s64, but it's also positive. */ | |
643a6545 AM |
825 | rts.tv_nsec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)) * |
826 | 1000; | |
827 | rts.tv_sec = timeout; | |
74910e6c | 828 | if (timespec_compare(&rts, &ts) >= 0) |
643a6545 AM |
829 | rts = ts; |
830 | if (copy_to_user(tsp, &rts, sizeof(rts))) { | |
9f72949f DW |
831 | sticky: |
832 | /* | |
833 | * If an application puts its timeval in read-only | |
834 | * memory, we don't want the Linux-specific update to | |
835 | * the timeval to cause a fault after the select has | |
836 | * completed successfully. However, because we're not | |
837 | * updating the timeval, we can't restart the system | |
838 | * call. | |
839 | */ | |
840 | if (ret == -ERESTARTNOHAND && timeout >= 0) | |
841 | ret = -EINTR; | |
842 | } | |
843 | } | |
844 | ||
845 | return ret; | |
846 | } | |
847 | #endif /* TIF_RESTORE_SIGMASK */ |