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