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