blob: 2c292146e2464836983913d7046b3279167f2ce7 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Milind Arun Choudhary022a1692007-05-08 00:29:02 -070017#include <linux/kernel.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#include <linux/syscalls.h>
19#include <linux/module.h>
20#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070021#include <linux/poll.h>
22#include <linux/personality.h> /* for STICKY_TIMEOUTS */
23#include <linux/file.h>
24#include <linux/fs.h>
Dipankar Sarmab8359962005-09-09 13:04:14 -070025#include <linux/rcupdate.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026
27#include <asm/uaccess.h>
28
Linus Torvalds1da177e2005-04-16 15:20:36 -070029struct 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 */
Adrian Bunk75c96f82005-05-05 16:16:09 -070050static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
51 poll_table *p);
Linus Torvalds1da177e2005-04-16 15:20:36 -070052
53void poll_initwait(struct poll_wqueues *pwq)
54{
55 init_poll_funcptr(&pwq->pt, __pollwait);
56 pwq->error = 0;
57 pwq->table = NULL;
Andi Kleen70674f92006-03-28 01:56:33 -080058 pwq->inline_index = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070059}
60
61EXPORT_SYMBOL(poll_initwait);
62
Andi Kleen70674f92006-03-28 01:56:33 -080063static void free_poll_entry(struct poll_table_entry *entry)
64{
WANG Congccf67802007-05-09 07:10:02 +020065 remove_wait_queue(entry->wait_address, &entry->wait);
Andi Kleen70674f92006-03-28 01:56:33 -080066 fput(entry->filp);
67}
68
Linus Torvalds1da177e2005-04-16 15:20:36 -070069void poll_freewait(struct poll_wqueues *pwq)
70{
71 struct poll_table_page * p = pwq->table;
Andi Kleen70674f92006-03-28 01:56:33 -080072 int i;
73 for (i = 0; i < pwq->inline_index; i++)
74 free_poll_entry(pwq->inline_entries + i);
Linus Torvalds1da177e2005-04-16 15:20:36 -070075 while (p) {
76 struct poll_table_entry * entry;
77 struct poll_table_page *old;
78
79 entry = p->entry;
80 do {
81 entry--;
Andi Kleen70674f92006-03-28 01:56:33 -080082 free_poll_entry(entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -070083 } while (entry > p->entries);
84 old = p;
85 p = p->next;
86 free_page((unsigned long) old);
87 }
88}
89
90EXPORT_SYMBOL(poll_freewait);
91
Andi Kleen70674f92006-03-28 01:56:33 -080092static struct poll_table_entry *poll_get_entry(poll_table *_p)
Linus Torvalds1da177e2005-04-16 15:20:36 -070093{
94 struct poll_wqueues *p = container_of(_p, struct poll_wqueues, pt);
95 struct poll_table_page *table = p->table;
96
Andi Kleen70674f92006-03-28 01:56:33 -080097 if (p->inline_index < N_INLINE_POLL_ENTRIES)
98 return p->inline_entries + p->inline_index++;
99
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100 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);
Andi Kleen70674f92006-03-28 01:56:33 -0800107 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108 }
109 new_table->entry = new_table->entries;
110 new_table->next = table;
111 p->table = new_table;
112 table = new_table;
113 }
114
Andi Kleen70674f92006-03-28 01:56:33 -0800115 return table->entry++;
116}
117
118/* Add a new entry */
119static 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);
WANG Congccf67802007-05-09 07:10:02 +0200129 add_wait_queue(wait_address, &entry->wait);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130}
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
138static int max_select_fd(unsigned long n, fd_set_bits *fds)
139{
140 unsigned long *open_fds;
141 unsigned long set;
142 int max;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700143 struct fdtable *fdt;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144
145 /* handle last in-complete long-word first */
146 set = ~(~0UL << (n & (__NFDBITS-1)));
147 n /= __NFDBITS;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700148 fdt = files_fdtable(current->files);
149 open_fds = fdt->open_fds->fds_bits+n;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 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;
169get_max:
170 do {
171 max++;
172 set >>= 1;
173 } while (set);
174 max += n * __NFDBITS;
175 }
176
177 return max;
178}
179
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180#define POLLIN_SET (POLLRDNORM | POLLRDBAND | POLLIN | POLLHUP | POLLERR)
181#define POLLOUT_SET (POLLWRBAND | POLLWRNORM | POLLOUT | POLLERR)
182#define POLLEX_SET (POLLPRI)
183
David Woodhouse9f729492006-01-18 17:44:05 -0800184int do_select(int n, fd_set_bits *fds, s64 *timeout)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185{
186 struct poll_wqueues table;
187 poll_table *wait;
188 int retval, i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189
Dipankar Sarmab8359962005-09-09 13:04:14 -0700190 rcu_read_lock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 retval = max_select_fd(n, fds);
Dipankar Sarmab8359962005-09-09 13:04:14 -0700192 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193
194 if (retval < 0)
195 return retval;
196 n = retval;
197
198 poll_initwait(&table);
199 wait = &table.pt;
David Woodhouse9f729492006-01-18 17:44:05 -0800200 if (!*timeout)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 wait = NULL;
202 retval = 0;
203 for (;;) {
204 unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp;
David Woodhouse9f729492006-01-18 17:44:05 -0800205 long __timeout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206
207 set_current_state(TASK_INTERRUPTIBLE);
208
209 inp = fds->in; outp = fds->out; exp = fds->ex;
210 rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex;
211
212 for (i = 0; i < n; ++rinp, ++routp, ++rexp) {
213 unsigned long in, out, ex, all_bits, bit = 1, mask, j;
214 unsigned long res_in = 0, res_out = 0, res_ex = 0;
Arjan van de Ven99ac48f2006-03-28 01:56:41 -0800215 const struct file_operations *f_op = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 struct file *file = NULL;
217
218 in = *inp++; out = *outp++; ex = *exp++;
219 all_bits = in | out | ex;
220 if (all_bits == 0) {
221 i += __NFDBITS;
222 continue;
223 }
224
225 for (j = 0; j < __NFDBITS; ++j, ++i, bit <<= 1) {
Eric Dumazete4a1f122006-03-28 01:56:34 -0800226 int fput_needed;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 if (i >= n)
228 break;
229 if (!(bit & all_bits))
230 continue;
Eric Dumazete4a1f122006-03-28 01:56:34 -0800231 file = fget_light(i, &fput_needed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232 if (file) {
233 f_op = file->f_op;
234 mask = DEFAULT_POLLMASK;
235 if (f_op && f_op->poll)
236 mask = (*f_op->poll)(file, retval ? NULL : wait);
Eric Dumazete4a1f122006-03-28 01:56:34 -0800237 fput_light(file, fput_needed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238 if ((mask & POLLIN_SET) && (in & bit)) {
239 res_in |= bit;
240 retval++;
241 }
242 if ((mask & POLLOUT_SET) && (out & bit)) {
243 res_out |= bit;
244 retval++;
245 }
246 if ((mask & POLLEX_SET) && (ex & bit)) {
247 res_ex |= bit;
248 retval++;
249 }
250 }
251 cond_resched();
252 }
253 if (res_in)
254 *rinp = res_in;
255 if (res_out)
256 *routp = res_out;
257 if (res_ex)
258 *rexp = res_ex;
259 }
260 wait = NULL;
David Woodhouse9f729492006-01-18 17:44:05 -0800261 if (retval || !*timeout || signal_pending(current))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262 break;
Pavel Machekf5264482008-04-21 22:15:06 +0000263 if (table.error) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264 retval = table.error;
265 break;
266 }
David Woodhouse9f729492006-01-18 17:44:05 -0800267
268 if (*timeout < 0) {
269 /* Wait indefinitely */
270 __timeout = MAX_SCHEDULE_TIMEOUT;
271 } else if (unlikely(*timeout >= (s64)MAX_SCHEDULE_TIMEOUT - 1)) {
272 /* Wait for longer than MAX_SCHEDULE_TIMEOUT. Do it in a loop */
273 __timeout = MAX_SCHEDULE_TIMEOUT - 1;
274 *timeout -= __timeout;
275 } else {
276 __timeout = *timeout;
277 *timeout = 0;
278 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 __timeout = schedule_timeout(__timeout);
David Woodhouse9f729492006-01-18 17:44:05 -0800280 if (*timeout >= 0)
281 *timeout += __timeout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282 }
283 __set_current_state(TASK_RUNNING);
284
285 poll_freewait(&table);
286
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 return retval;
288}
289
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290/*
291 * We can actually return ERESTARTSYS instead of EINTR, but I'd
292 * like to be certain this leads to no problems. So I return
293 * EINTR just for safety.
294 *
295 * Update: ERESTARTSYS breaks at least the xview clock binary, so
296 * I'm trying ERESTARTNOHAND which restart only when you want to.
297 */
298#define MAX_SELECT_SECONDS \
299 ((unsigned long) (MAX_SCHEDULE_TIMEOUT / HZ)-1)
300
David Woodhouse9f729492006-01-18 17:44:05 -0800301static int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
302 fd_set __user *exp, s64 *timeout)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303{
304 fd_set_bits fds;
Andrew Morton29ff2db2006-04-10 22:52:46 -0700305 void *bits;
Vadim Lobanovbbea9f62006-12-10 02:21:12 -0800306 int ret, max_fds;
Mitchell Blank Jrb04eb6a2006-04-10 22:54:08 -0700307 unsigned int size;
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700308 struct fdtable *fdt;
Andi Kleen70674f92006-03-28 01:56:33 -0800309 /* Allocate small arguments on the stack to save memory and be faster */
Jes Sorensen30c14e42006-03-31 11:18:57 -0500310 long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312 ret = -EINVAL;
313 if (n < 0)
314 goto out_nofds;
315
Vadim Lobanovbbea9f62006-12-10 02:21:12 -0800316 /* max_fds can increase, so grab it once to avoid race */
Dipankar Sarmab8359962005-09-09 13:04:14 -0700317 rcu_read_lock();
Dipankar Sarmabadf1662005-09-09 13:04:10 -0700318 fdt = files_fdtable(current->files);
Vadim Lobanovbbea9f62006-12-10 02:21:12 -0800319 max_fds = fdt->max_fds;
Dipankar Sarmab8359962005-09-09 13:04:14 -0700320 rcu_read_unlock();
Vadim Lobanovbbea9f62006-12-10 02:21:12 -0800321 if (n > max_fds)
322 n = max_fds;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323
324 /*
325 * We need 6 bitmaps (in/out/ex for both incoming and outgoing),
326 * since we used fdset we need to allocate memory in units of
327 * long-words.
328 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329 size = FDS_BYTES(n);
Mitchell Blank Jrb04eb6a2006-04-10 22:54:08 -0700330 bits = stack_fds;
331 if (size > sizeof(stack_fds) / 6) {
332 /* Not enough space in on-stack array; must use kmalloc */
333 ret = -ENOMEM;
Andi Kleen70674f92006-03-28 01:56:33 -0800334 bits = kmalloc(6 * size, GFP_KERNEL);
Mitchell Blank Jrb04eb6a2006-04-10 22:54:08 -0700335 if (!bits)
336 goto out_nofds;
337 }
Andrew Morton29ff2db2006-04-10 22:52:46 -0700338 fds.in = bits;
339 fds.out = bits + size;
340 fds.ex = bits + 2*size;
341 fds.res_in = bits + 3*size;
342 fds.res_out = bits + 4*size;
343 fds.res_ex = bits + 5*size;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344
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
David Woodhouse9f729492006-01-18 17:44:05 -0800353 ret = do_select(n, &fds, timeout);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354
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
369out:
Andi Kleen70674f92006-03-28 01:56:33 -0800370 if (bits != stack_fds)
371 kfree(bits);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372out_nofds:
373 return ret;
374}
375
David Woodhouse9f729492006-01-18 17:44:05 -0800376asmlinkage long sys_select(int n, fd_set __user *inp, fd_set __user *outp,
377 fd_set __user *exp, struct timeval __user *tvp)
378{
379 s64 timeout = -1;
380 struct timeval tv;
381 int ret;
382
383 if (tvp) {
384 if (copy_from_user(&tv, tvp, sizeof(tv)))
385 return -EFAULT;
386
387 if (tv.tv_sec < 0 || tv.tv_usec < 0)
388 return -EINVAL;
389
390 /* Cast to u64 to make GCC stop complaining */
391 if ((u64)tv.tv_sec >= (u64)MAX_INT64_SECONDS)
392 timeout = -1; /* infinite */
393 else {
Milind Arun Choudhary022a1692007-05-08 00:29:02 -0700394 timeout = DIV_ROUND_UP(tv.tv_usec, USEC_PER_SEC/HZ);
David Woodhouse9f729492006-01-18 17:44:05 -0800395 timeout += tv.tv_sec * HZ;
396 }
397 }
398
399 ret = core_sys_select(n, inp, outp, exp, &timeout);
400
401 if (tvp) {
Andrew Morton643a6542006-02-11 17:55:52 -0800402 struct timeval rtv;
403
David Woodhouse9f729492006-01-18 17:44:05 -0800404 if (current->personality & STICKY_TIMEOUTS)
405 goto sticky;
Andrew Morton643a6542006-02-11 17:55:52 -0800406 rtv.tv_usec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ));
407 rtv.tv_sec = timeout;
Andrew Morton74910e62006-02-17 13:52:58 -0800408 if (timeval_compare(&rtv, &tv) >= 0)
Andrew Morton643a6542006-02-11 17:55:52 -0800409 rtv = tv;
410 if (copy_to_user(tvp, &rtv, sizeof(rtv))) {
David Woodhouse9f729492006-01-18 17:44:05 -0800411sticky:
412 /*
413 * If an application puts its timeval in read-only
414 * memory, we don't want the Linux-specific update to
415 * the timeval to cause a fault after the select has
416 * completed successfully. However, because we're not
417 * updating the timeval, we can't restart the system
418 * call.
419 */
420 if (ret == -ERESTARTNOHAND)
421 ret = -EINTR;
422 }
423 }
424
425 return ret;
426}
427
Roland McGrathf3de2722008-04-30 00:53:09 -0700428#ifdef HAVE_SET_RESTORE_SIGMASK
David Woodhouse9f729492006-01-18 17:44:05 -0800429asmlinkage long sys_pselect7(int n, fd_set __user *inp, fd_set __user *outp,
430 fd_set __user *exp, struct timespec __user *tsp,
431 const sigset_t __user *sigmask, size_t sigsetsize)
432{
433 s64 timeout = MAX_SCHEDULE_TIMEOUT;
434 sigset_t ksigmask, sigsaved;
435 struct timespec ts;
436 int ret;
437
438 if (tsp) {
439 if (copy_from_user(&ts, tsp, sizeof(ts)))
440 return -EFAULT;
441
442 if (ts.tv_sec < 0 || ts.tv_nsec < 0)
443 return -EINVAL;
444
445 /* Cast to u64 to make GCC stop complaining */
446 if ((u64)ts.tv_sec >= (u64)MAX_INT64_SECONDS)
447 timeout = -1; /* infinite */
448 else {
Milind Arun Choudhary022a1692007-05-08 00:29:02 -0700449 timeout = DIV_ROUND_UP(ts.tv_nsec, NSEC_PER_SEC/HZ);
David Woodhouse9f729492006-01-18 17:44:05 -0800450 timeout += ts.tv_sec * HZ;
451 }
452 }
453
454 if (sigmask) {
455 /* XXX: Don't preclude handling different sized sigset_t's. */
456 if (sigsetsize != sizeof(sigset_t))
457 return -EINVAL;
458 if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask)))
459 return -EFAULT;
460
461 sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
462 sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
463 }
464
465 ret = core_sys_select(n, inp, outp, exp, &timeout);
466
467 if (tsp) {
Andrew Morton643a6542006-02-11 17:55:52 -0800468 struct timespec rts;
469
David Woodhouse9f729492006-01-18 17:44:05 -0800470 if (current->personality & STICKY_TIMEOUTS)
471 goto sticky;
Andrew Morton643a6542006-02-11 17:55:52 -0800472 rts.tv_nsec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)) *
473 1000;
474 rts.tv_sec = timeout;
Andrew Morton74910e62006-02-17 13:52:58 -0800475 if (timespec_compare(&rts, &ts) >= 0)
Andrew Morton643a6542006-02-11 17:55:52 -0800476 rts = ts;
477 if (copy_to_user(tsp, &rts, sizeof(rts))) {
David Woodhouse9f729492006-01-18 17:44:05 -0800478sticky:
479 /*
480 * If an application puts its timeval in read-only
481 * memory, we don't want the Linux-specific update to
482 * the timeval to cause a fault after the select has
483 * completed successfully. However, because we're not
484 * updating the timeval, we can't restart the system
485 * call.
486 */
487 if (ret == -ERESTARTNOHAND)
488 ret = -EINTR;
489 }
490 }
491
492 if (ret == -ERESTARTNOHAND) {
493 /*
494 * Don't restore the signal mask yet. Let do_signal() deliver
495 * the signal on the way back to userspace, before the signal
496 * mask is restored.
497 */
498 if (sigmask) {
499 memcpy(&current->saved_sigmask, &sigsaved,
500 sizeof(sigsaved));
Roland McGrath4e4c22c2008-04-30 00:53:06 -0700501 set_restore_sigmask();
David Woodhouse9f729492006-01-18 17:44:05 -0800502 }
503 } else if (sigmask)
504 sigprocmask(SIG_SETMASK, &sigsaved, NULL);
505
506 return ret;
507}
508
509/*
510 * Most architectures can't handle 7-argument syscalls. So we provide a
511 * 6-argument version where the sixth argument is a pointer to a structure
512 * which has a pointer to the sigset_t itself followed by a size_t containing
513 * the sigset size.
514 */
515asmlinkage long sys_pselect6(int n, fd_set __user *inp, fd_set __user *outp,
516 fd_set __user *exp, struct timespec __user *tsp, void __user *sig)
517{
518 size_t sigsetsize = 0;
519 sigset_t __user *up = NULL;
520
521 if (sig) {
522 if (!access_ok(VERIFY_READ, sig, sizeof(void *)+sizeof(size_t))
Al Viroe110ab92006-02-01 05:26:09 -0500523 || __get_user(up, (sigset_t __user * __user *)sig)
David Woodhouse9f729492006-01-18 17:44:05 -0800524 || __get_user(sigsetsize,
Al Viroe110ab92006-02-01 05:26:09 -0500525 (size_t __user *)(sig+sizeof(void *))))
David Woodhouse9f729492006-01-18 17:44:05 -0800526 return -EFAULT;
527 }
528
529 return sys_pselect7(n, inp, outp, exp, tsp, up, sigsetsize);
530}
Roland McGrathf3de2722008-04-30 00:53:09 -0700531#endif /* HAVE_SET_RESTORE_SIGMASK */
David Woodhouse9f729492006-01-18 17:44:05 -0800532
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533struct poll_list {
534 struct poll_list *next;
535 int len;
536 struct pollfd entries[0];
537};
538
539#define POLLFD_PER_PAGE ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd))
540
Vadim Lobanov4a4b69f2006-06-23 02:05:16 -0700541/*
542 * Fish for pollable events on the pollfd->fd file descriptor. We're only
543 * interested in events matching the pollfd->events mask, and the result
544 * matching that mask is both recorded in pollfd->revents and returned. The
545 * pwait poll_table will be used by the fd-provided poll handler for waiting,
546 * if non-NULL.
547 */
548static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549{
Vadim Lobanov4a4b69f2006-06-23 02:05:16 -0700550 unsigned int mask;
551 int fd;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552
Vadim Lobanov4a4b69f2006-06-23 02:05:16 -0700553 mask = 0;
554 fd = pollfd->fd;
555 if (fd >= 0) {
556 int fput_needed;
557 struct file * file;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558
Vadim Lobanov4a4b69f2006-06-23 02:05:16 -0700559 file = fget_light(fd, &fput_needed);
560 mask = POLLNVAL;
561 if (file != NULL) {
562 mask = DEFAULT_POLLMASK;
563 if (file->f_op && file->f_op->poll)
564 mask = file->f_op->poll(file, pwait);
565 /* Mask out unneeded events. */
566 mask &= pollfd->events | POLLERR | POLLHUP;
567 fput_light(file, fput_needed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569 }
Vadim Lobanov4a4b69f2006-06-23 02:05:16 -0700570 pollfd->revents = mask;
571
572 return mask;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573}
574
575static int do_poll(unsigned int nfds, struct poll_list *list,
David Woodhouse9f729492006-01-18 17:44:05 -0800576 struct poll_wqueues *wait, s64 *timeout)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577{
578 int count = 0;
579 poll_table* pt = &wait->pt;
580
David Woodhouse9f729492006-01-18 17:44:05 -0800581 /* Optimise the no-wait case */
582 if (!(*timeout))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583 pt = NULL;
Oleg Nesterov9bf084f2007-10-16 23:26:18 -0700584
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585 for (;;) {
586 struct poll_list *walk;
David Woodhouse9f729492006-01-18 17:44:05 -0800587 long __timeout;
588
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589 set_current_state(TASK_INTERRUPTIBLE);
Vadim Lobanov4a4b69f2006-06-23 02:05:16 -0700590 for (walk = list; walk != NULL; walk = walk->next) {
591 struct pollfd * pfd, * pfd_end;
592
593 pfd = walk->entries;
594 pfd_end = pfd + walk->len;
595 for (; pfd != pfd_end; pfd++) {
596 /*
597 * Fish for events. If we found one, record it
598 * and kill the poll_table, so we don't
599 * needlessly register any other waiters after
600 * this. They'll get immediately deregistered
601 * when we break out and return.
602 */
603 if (do_pollfd(pfd, pt)) {
604 count++;
605 pt = NULL;
606 }
607 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608 }
Vadim Lobanov4a4b69f2006-06-23 02:05:16 -0700609 /*
610 * All waiters have already been registered, so don't provide
611 * a poll_table to them on the next loop iteration.
612 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 pt = NULL;
Oleg Nesterov9bf084f2007-10-16 23:26:18 -0700614 if (!count) {
615 count = wait->error;
616 if (signal_pending(current))
617 count = -EINTR;
618 }
619 if (count || !*timeout)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620 break;
David Woodhouse9f729492006-01-18 17:44:05 -0800621
622 if (*timeout < 0) {
623 /* Wait indefinitely */
624 __timeout = MAX_SCHEDULE_TIMEOUT;
625 } else if (unlikely(*timeout >= (s64)MAX_SCHEDULE_TIMEOUT-1)) {
626 /*
627 * Wait for longer than MAX_SCHEDULE_TIMEOUT. Do it in
628 * a loop
629 */
630 __timeout = MAX_SCHEDULE_TIMEOUT - 1;
631 *timeout -= __timeout;
632 } else {
633 __timeout = *timeout;
634 *timeout = 0;
635 }
636
637 __timeout = schedule_timeout(__timeout);
638 if (*timeout >= 0)
639 *timeout += __timeout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640 }
641 __set_current_state(TASK_RUNNING);
642 return count;
643}
644
Andi Kleen70674f92006-03-28 01:56:33 -0800645#define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \
646 sizeof(struct pollfd))
647
David Woodhouse9f729492006-01-18 17:44:05 -0800648int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds, s64 *timeout)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700649{
650 struct poll_wqueues table;
Oleg Nesterov252e5722007-10-16 23:26:17 -0700651 int err = -EFAULT, fdcount, len, size;
Jes Sorensen30c14e42006-03-31 11:18:57 -0500652 /* Allocate small arguments on the stack to save memory and be
653 faster - use long to make sure the buffer is aligned properly
654 on 64 bit archs to avoid unaligned access */
655 long stack_pps[POLL_STACK_ALLOC/sizeof(long)];
Oleg Nesterov252e5722007-10-16 23:26:17 -0700656 struct poll_list *const head = (struct poll_list *)stack_pps;
657 struct poll_list *walk = head;
658 unsigned long todo = nfds;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659
Chris Snook4e6fd332006-09-29 02:01:33 -0700660 if (nfds > current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661 return -EINVAL;
662
Oleg Nesterov252e5722007-10-16 23:26:17 -0700663 len = min_t(unsigned int, nfds, N_STACK_PPS);
664 for (;;) {
665 walk->next = NULL;
666 walk->len = len;
667 if (!len)
668 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669
Oleg Nesterov252e5722007-10-16 23:26:17 -0700670 if (copy_from_user(walk->entries, ufds + nfds-todo,
671 sizeof(struct pollfd) * walk->len))
672 goto out_fds;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673
Oleg Nesterov252e5722007-10-16 23:26:17 -0700674 todo -= walk->len;
675 if (!todo)
676 break;
677
678 len = min(todo, POLLFD_PER_PAGE);
679 size = sizeof(struct poll_list) + sizeof(struct pollfd) * len;
680 walk = walk->next = kmalloc(size, GFP_KERNEL);
681 if (!walk) {
682 err = -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700683 goto out_fds;
684 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685 }
David Woodhouse9f729492006-01-18 17:44:05 -0800686
Oleg Nesterov252e5722007-10-16 23:26:17 -0700687 poll_initwait(&table);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688 fdcount = do_poll(nfds, head, &table, timeout);
Oleg Nesterov252e5722007-10-16 23:26:17 -0700689 poll_freewait(&table);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690
Oleg Nesterov252e5722007-10-16 23:26:17 -0700691 for (walk = head; walk; walk = walk->next) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700692 struct pollfd *fds = walk->entries;
693 int j;
694
Oleg Nesterov252e5722007-10-16 23:26:17 -0700695 for (j = 0; j < walk->len; j++, ufds++)
696 if (__put_user(fds[j].revents, &ufds->revents))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697 goto out_fds;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698 }
Oleg Nesterov252e5722007-10-16 23:26:17 -0700699
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700 err = fdcount;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701out_fds:
Oleg Nesterov252e5722007-10-16 23:26:17 -0700702 walk = head->next;
703 while (walk) {
704 struct poll_list *pos = walk;
705 walk = walk->next;
706 kfree(pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707 }
Oleg Nesterov252e5722007-10-16 23:26:17 -0700708
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709 return err;
710}
David Woodhouse9f729492006-01-18 17:44:05 -0800711
Chris Wright3075d9d2007-10-16 23:27:18 -0700712static long do_restart_poll(struct restart_block *restart_block)
713{
714 struct pollfd __user *ufds = (struct pollfd __user*)restart_block->arg0;
715 int nfds = restart_block->arg1;
716 s64 timeout = ((s64)restart_block->arg3<<32) | (s64)restart_block->arg2;
717 int ret;
718
719 ret = do_sys_poll(ufds, nfds, &timeout);
720 if (ret == -EINTR) {
721 restart_block->fn = do_restart_poll;
722 restart_block->arg2 = timeout & 0xFFFFFFFF;
723 restart_block->arg3 = (u64)timeout >> 32;
724 ret = -ERESTART_RESTARTBLOCK;
725 }
726 return ret;
727}
728
David Woodhouse9f729492006-01-18 17:44:05 -0800729asmlinkage long sys_poll(struct pollfd __user *ufds, unsigned int nfds,
730 long timeout_msecs)
731{
Frode Isaksen04a34462006-06-25 05:49:09 -0700732 s64 timeout_jiffies;
Chris Wright3075d9d2007-10-16 23:27:18 -0700733 int ret;
David Woodhouse9f729492006-01-18 17:44:05 -0800734
Frode Isaksen04a34462006-06-25 05:49:09 -0700735 if (timeout_msecs > 0) {
David Woodhouse9f729492006-01-18 17:44:05 -0800736#if HZ > 1000
737 /* We can only overflow if HZ > 1000 */
738 if (timeout_msecs / 1000 > (s64)0x7fffffffffffffffULL / (s64)HZ)
739 timeout_jiffies = -1;
740 else
741#endif
Karsten Wiese844fcc52008-02-06 01:37:59 -0800742 timeout_jiffies = msecs_to_jiffies(timeout_msecs) + 1;
Frode Isaksen04a34462006-06-25 05:49:09 -0700743 } else {
744 /* Infinite (< 0) or no (0) timeout */
745 timeout_jiffies = timeout_msecs;
David Woodhouse9f729492006-01-18 17:44:05 -0800746 }
747
Chris Wright3075d9d2007-10-16 23:27:18 -0700748 ret = do_sys_poll(ufds, nfds, &timeout_jiffies);
749 if (ret == -EINTR) {
750 struct restart_block *restart_block;
751 restart_block = &current_thread_info()->restart_block;
752 restart_block->fn = do_restart_poll;
753 restart_block->arg0 = (unsigned long)ufds;
754 restart_block->arg1 = nfds;
755 restart_block->arg2 = timeout_jiffies & 0xFFFFFFFF;
756 restart_block->arg3 = (u64)timeout_jiffies >> 32;
757 ret = -ERESTART_RESTARTBLOCK;
758 }
759 return ret;
David Woodhouse9f729492006-01-18 17:44:05 -0800760}
761
Roland McGrathf3de2722008-04-30 00:53:09 -0700762#ifdef HAVE_SET_RESTORE_SIGMASK
David Woodhouse9f729492006-01-18 17:44:05 -0800763asmlinkage long sys_ppoll(struct pollfd __user *ufds, unsigned int nfds,
764 struct timespec __user *tsp, const sigset_t __user *sigmask,
765 size_t sigsetsize)
766{
767 sigset_t ksigmask, sigsaved;
768 struct timespec ts;
769 s64 timeout = -1;
770 int ret;
771
772 if (tsp) {
773 if (copy_from_user(&ts, tsp, sizeof(ts)))
774 return -EFAULT;
775
776 /* Cast to u64 to make GCC stop complaining */
777 if ((u64)ts.tv_sec >= (u64)MAX_INT64_SECONDS)
778 timeout = -1; /* infinite */
779 else {
Milind Arun Choudhary022a1692007-05-08 00:29:02 -0700780 timeout = DIV_ROUND_UP(ts.tv_nsec, NSEC_PER_SEC/HZ);
David Woodhouse9f729492006-01-18 17:44:05 -0800781 timeout += ts.tv_sec * HZ;
782 }
783 }
784
785 if (sigmask) {
786 /* XXX: Don't preclude handling different sized sigset_t's. */
787 if (sigsetsize != sizeof(sigset_t))
788 return -EINVAL;
789 if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask)))
790 return -EFAULT;
791
792 sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
793 sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
794 }
795
796 ret = do_sys_poll(ufds, nfds, &timeout);
797
798 /* We can restart this syscall, usually */
799 if (ret == -EINTR) {
800 /*
801 * Don't restore the signal mask yet. Let do_signal() deliver
802 * the signal on the way back to userspace, before the signal
803 * mask is restored.
804 */
805 if (sigmask) {
806 memcpy(&current->saved_sigmask, &sigsaved,
807 sizeof(sigsaved));
Roland McGrath4e4c22c2008-04-30 00:53:06 -0700808 set_restore_sigmask();
David Woodhouse9f729492006-01-18 17:44:05 -0800809 }
810 ret = -ERESTARTNOHAND;
811 } else if (sigmask)
812 sigprocmask(SIG_SETMASK, &sigsaved, NULL);
813
814 if (tsp && timeout >= 0) {
Andrew Morton643a6542006-02-11 17:55:52 -0800815 struct timespec rts;
816
David Woodhouse9f729492006-01-18 17:44:05 -0800817 if (current->personality & STICKY_TIMEOUTS)
818 goto sticky;
819 /* Yes, we know it's actually an s64, but it's also positive. */
Andrew Morton643a6542006-02-11 17:55:52 -0800820 rts.tv_nsec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)) *
821 1000;
822 rts.tv_sec = timeout;
Andrew Morton74910e62006-02-17 13:52:58 -0800823 if (timespec_compare(&rts, &ts) >= 0)
Andrew Morton643a6542006-02-11 17:55:52 -0800824 rts = ts;
825 if (copy_to_user(tsp, &rts, sizeof(rts))) {
David Woodhouse9f729492006-01-18 17:44:05 -0800826 sticky:
827 /*
828 * If an application puts its timeval in read-only
829 * memory, we don't want the Linux-specific update to
830 * the timeval to cause a fault after the select has
831 * completed successfully. However, because we're not
832 * updating the timeval, we can't restart the system
833 * call.
834 */
835 if (ret == -ERESTARTNOHAND && timeout >= 0)
836 ret = -EINTR;
837 }
838 }
839
840 return ret;
841}
Roland McGrathf3de2722008-04-30 00:53:09 -0700842#endif /* HAVE_SET_RESTORE_SIGMASK */