Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0
2 : /*
3 : * This file contains the procedures for the handling of select and poll
4 : *
5 : * Created for Linux based loosely upon Mathius Lattner's minix
6 : * patches by Peter MacDonald. Heavily edited by Linus.
7 : *
8 : * 4 February 1994
9 : * COFF/ELF binary emulation. If the process has the STICKY_TIMEOUTS
10 : * flag set in its personality we do *not* modify the given timeout
11 : * parameter to reflect time remaining.
12 : *
13 : * 24 January 2000
14 : * Changed sys_poll()/do_poll() to use PAGE_SIZE chunk-based allocation
15 : * of fds to overcome nfds < 16390 descriptors limit (Tigran Aivazian).
16 : */
17 :
18 : #include <linux/compat.h>
19 : #include <linux/kernel.h>
20 : #include <linux/sched/signal.h>
21 : #include <linux/sched/rt.h>
22 : #include <linux/syscalls.h>
23 : #include <linux/export.h>
24 : #include <linux/slab.h>
25 : #include <linux/poll.h>
26 : #include <linux/personality.h> /* for STICKY_TIMEOUTS */
27 : #include <linux/file.h>
28 : #include <linux/fdtable.h>
29 : #include <linux/fs.h>
30 : #include <linux/rcupdate.h>
31 : #include <linux/hrtimer.h>
32 : #include <linux/freezer.h>
33 : #include <net/busy_poll.h>
34 : #include <linux/vmalloc.h>
35 :
36 : #include <linux/uaccess.h>
37 :
38 :
39 : /*
40 : * Estimate expected accuracy in ns from a timeval.
41 : *
42 : * After quite a bit of churning around, we've settled on
43 : * a simple thing of taking 0.1% of the timeout as the
44 : * slack, with a cap of 100 msec.
45 : * "nice" tasks get a 0.5% slack instead.
46 : *
47 : * Consider this comment an open invitation to come up with even
48 : * better solutions..
49 : */
50 :
51 : #define MAX_SLACK (100 * NSEC_PER_MSEC)
52 :
53 3443291 : static long __estimate_accuracy(struct timespec64 *tv)
54 : {
55 3443291 : long slack;
56 3443291 : int divfactor = 1000;
57 :
58 3443291 : if (tv->tv_sec < 0)
59 : return 0;
60 :
61 3443291 : if (task_nice(current) > 0)
62 1076 : divfactor = divfactor / 5;
63 :
64 3443291 : if (tv->tv_sec > MAX_SLACK / (NSEC_PER_SEC/divfactor))
65 : return MAX_SLACK;
66 :
67 3301892 : slack = tv->tv_nsec / divfactor;
68 3301892 : slack += tv->tv_sec * (NSEC_PER_SEC/divfactor);
69 :
70 3301892 : if (slack > MAX_SLACK)
71 : return MAX_SLACK;
72 :
73 : return slack;
74 : }
75 :
76 3443308 : u64 select_estimate_accuracy(struct timespec64 *tv)
77 : {
78 3443308 : u64 ret;
79 3443308 : struct timespec64 now;
80 :
81 : /*
82 : * Realtime tasks get a slack of 0 for obvious reasons.
83 : */
84 :
85 3443308 : if (rt_task(current))
86 : return 0;
87 :
88 3443308 : ktime_get_ts64(&now);
89 3443328 : now = timespec64_sub(*tv, now);
90 3443324 : ret = __estimate_accuracy(&now);
91 3443324 : if (ret < current->timer_slack_ns)
92 151815 : return current->timer_slack_ns;
93 : return ret;
94 : }
95 :
96 :
97 :
98 : struct poll_table_page {
99 : struct poll_table_page * next;
100 : struct poll_table_entry * entry;
101 : struct poll_table_entry entries[];
102 : };
103 :
104 : #define POLL_TABLE_FULL(table) \
105 : ((unsigned long)((table)->entry+1) > PAGE_SIZE + (unsigned long)(table))
106 :
107 : /*
108 : * Ok, Peter made a complicated, but straightforward multiple_wait() function.
109 : * I have rewritten this, taking some shortcuts: This code may not be easy to
110 : * follow, but it should be free of race-conditions, and it's practical. If you
111 : * understand what I'm doing here, then you understand how the linux
112 : * sleep/wakeup mechanism works.
113 : *
114 : * Two very simple procedures, poll_wait() and poll_freewait() make all the
115 : * work. poll_wait() is an inline-function defined in <linux/poll.h>,
116 : * as all select/poll functions have to call it to add an entry to the
117 : * poll table.
118 : */
119 : static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
120 : poll_table *p);
121 :
122 0 : void poll_initwait(struct poll_wqueues *pwq)
123 : {
124 7971745 : init_poll_funcptr(&pwq->pt, __pollwait);
125 7971745 : pwq->polling_task = current;
126 7971745 : pwq->triggered = 0;
127 7971745 : pwq->error = 0;
128 7971745 : pwq->table = NULL;
129 7971745 : pwq->inline_index = 0;
130 0 : }
131 : EXPORT_SYMBOL(poll_initwait);
132 :
133 7207052 : static void free_poll_entry(struct poll_table_entry *entry)
134 : {
135 7207052 : remove_wait_queue(entry->wait_address, &entry->wait);
136 7207114 : fput(entry->filp);
137 7207227 : }
138 :
139 7971641 : void poll_freewait(struct poll_wqueues *pwq)
140 : {
141 7971641 : struct poll_table_page * p = pwq->table;
142 7971641 : int i;
143 15029908 : for (i = 0; i < pwq->inline_index; i++)
144 7058087 : free_poll_entry(pwq->inline_entries + i);
145 8120745 : while (p) {
146 148971 : struct poll_table_entry * entry;
147 148971 : struct poll_table_page *old;
148 :
149 148971 : entry = p->entry;
150 148971 : do {
151 148971 : entry--;
152 148971 : free_poll_entry(entry);
153 148971 : } while (entry > p->entries);
154 148971 : old = p;
155 148971 : p = p->next;
156 148971 : free_page((unsigned long) old);
157 : }
158 7971774 : }
159 : EXPORT_SYMBOL(poll_freewait);
160 :
161 7207211 : static struct poll_table_entry *poll_get_entry(struct poll_wqueues *p)
162 : {
163 7207211 : struct poll_table_page *table = p->table;
164 :
165 7207211 : if (p->inline_index < N_INLINE_POLL_ENTRIES)
166 7058240 : return p->inline_entries + p->inline_index++;
167 :
168 148971 : if (!table || POLL_TABLE_FULL(table)) {
169 148971 : struct poll_table_page *new_table;
170 :
171 148971 : new_table = (struct poll_table_page *) __get_free_page(GFP_KERNEL);
172 148971 : if (!new_table) {
173 0 : p->error = -ENOMEM;
174 0 : return NULL;
175 : }
176 148971 : new_table->entry = new_table->entries;
177 148971 : new_table->next = table;
178 148971 : p->table = new_table;
179 148971 : table = new_table;
180 : }
181 :
182 148971 : return table->entry++;
183 : }
184 :
185 4965064 : static int __pollwake(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
186 : {
187 4965064 : struct poll_wqueues *pwq = wait->private;
188 4965064 : DECLARE_WAITQUEUE(dummy_wait, pwq->polling_task);
189 :
190 : /*
191 : * Although this function is called under waitqueue lock, LOCK
192 : * doesn't imply write barrier and the users expect write
193 : * barrier semantics on wakeup functions. The following
194 : * smp_wmb() is equivalent to smp_wmb() in try_to_wake_up()
195 : * and is paired with smp_store_mb() in poll_schedule_timeout.
196 : */
197 4965064 : smp_wmb();
198 4965063 : pwq->triggered = 1;
199 :
200 : /*
201 : * Perform the default wake up operation using a dummy
202 : * waitqueue.
203 : *
204 : * TODO: This is hacky but there currently is no interface to
205 : * pass in @sync. @sync is scheduled to be removed and once
206 : * that happens, wake_up_process() can be used directly.
207 : */
208 4965063 : return default_wake_function(&dummy_wait, mode, sync, key);
209 : }
210 :
211 6535056 : static int pollwake(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
212 : {
213 6535056 : struct poll_table_entry *entry;
214 :
215 6535056 : entry = container_of(wait, struct poll_table_entry, wait);
216 6535056 : if (key && !(key_to_poll(key) & entry->key))
217 : return 0;
218 4965088 : return __pollwake(wait, mode, sync, key);
219 : }
220 :
221 : /* Add a new entry */
222 7207257 : static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
223 : poll_table *p)
224 : {
225 7207257 : struct poll_wqueues *pwq = container_of(p, struct poll_wqueues, pt);
226 7207257 : struct poll_table_entry *entry = poll_get_entry(pwq);
227 7207190 : if (!entry)
228 : return;
229 7207190 : entry->filp = get_file(filp);
230 7207395 : entry->wait_address = wait_address;
231 7207395 : entry->key = p->_key;
232 7207395 : init_waitqueue_func_entry(&entry->wait, pollwake);
233 7207395 : entry->wait.private = pwq;
234 7207395 : add_wait_queue(wait_address, &entry->wait);
235 : }
236 :
237 4554596 : static int poll_schedule_timeout(struct poll_wqueues *pwq, int state,
238 : ktime_t *expires, unsigned long slack)
239 : {
240 4554596 : int rc = -EINTR;
241 :
242 4554596 : set_current_state(state);
243 4554783 : if (!pwq->triggered)
244 4554666 : rc = schedule_hrtimeout_range(expires, slack, HRTIMER_MODE_ABS);
245 4554728 : __set_current_state(TASK_RUNNING);
246 :
247 : /*
248 : * Prepare for the next iteration.
249 : *
250 : * The following smp_store_mb() serves two purposes. First, it's
251 : * the counterpart rmb of the wmb in pollwake() such that data
252 : * written before wake up is always visible after wake up.
253 : * Second, the full barrier guarantees that triggered clearing
254 : * doesn't pass event check of the next iteration. Note that
255 : * this problem doesn't exist for the first iteration as
256 : * add_wait_queue() has full barrier semantics.
257 : */
258 4554728 : smp_store_mb(pwq->triggered, 0);
259 :
260 4554778 : return rc;
261 : }
262 :
263 : /**
264 : * poll_select_set_timeout - helper function to setup the timeout value
265 : * @to: pointer to timespec64 variable for the final timeout
266 : * @sec: seconds (from user space)
267 : * @nsec: nanoseconds (from user space)
268 : *
269 : * Note, we do not use a timespec for the user space value here, That
270 : * way we can use the function for timeval and compat interfaces as well.
271 : *
272 : * Returns -EINVAL if sec/nsec are not normalized. Otherwise 0.
273 : */
274 6482238 : int poll_select_set_timeout(struct timespec64 *to, time64_t sec, long nsec)
275 : {
276 6482238 : struct timespec64 ts = {.tv_sec = sec, .tv_nsec = nsec};
277 :
278 6482238 : if (!timespec64_valid(&ts))
279 : return -EINVAL;
280 :
281 : /* Optimize for the zero timeout value here */
282 6482238 : if (!sec && !nsec) {
283 3261269 : to->tv_sec = to->tv_nsec = 0;
284 : } else {
285 3220969 : ktime_get_ts64(to);
286 3220965 : *to = timespec64_add_safe(*to, ts);
287 : }
288 : return 0;
289 : }
290 :
291 : enum poll_time_type {
292 : PT_TIMEVAL = 0,
293 : PT_OLD_TIMEVAL = 1,
294 : PT_TIMESPEC = 2,
295 : PT_OLD_TIMESPEC = 3,
296 : };
297 :
298 4036961 : static int poll_select_finish(struct timespec64 *end_time,
299 : void __user *p,
300 : enum poll_time_type pt_type, int ret)
301 : {
302 4036961 : struct timespec64 rts;
303 :
304 4036961 : restore_saved_sigmask_unless(ret == -ERESTARTNOHAND);
305 :
306 4036949 : if (!p)
307 : return ret;
308 :
309 3162836 : if (current->personality & STICKY_TIMEOUTS)
310 0 : goto sticky;
311 :
312 : /* No update for zero timeout */
313 3162836 : if (!end_time->tv_sec && !end_time->tv_nsec)
314 : return ret;
315 :
316 2944041 : ktime_get_ts64(&rts);
317 2944062 : rts = timespec64_sub(*end_time, rts);
318 2944047 : if (rts.tv_sec < 0)
319 116499 : rts.tv_sec = rts.tv_nsec = 0;
320 :
321 :
322 2944047 : switch (pt_type) {
323 : case PT_TIMEVAL:
324 : {
325 0 : struct __kernel_old_timeval rtv;
326 :
327 0 : if (sizeof(rtv) > sizeof(rtv.tv_sec) + sizeof(rtv.tv_usec))
328 : memset(&rtv, 0, sizeof(rtv));
329 0 : rtv.tv_sec = rts.tv_sec;
330 0 : rtv.tv_usec = rts.tv_nsec / NSEC_PER_USEC;
331 0 : if (!copy_to_user(p, &rtv, sizeof(rtv)))
332 0 : return ret;
333 : }
334 0 : break;
335 0 : case PT_OLD_TIMEVAL:
336 : {
337 0 : struct old_timeval32 rtv;
338 :
339 0 : rtv.tv_sec = rts.tv_sec;
340 0 : rtv.tv_usec = rts.tv_nsec / NSEC_PER_USEC;
341 0 : if (!copy_to_user(p, &rtv, sizeof(rtv)))
342 0 : return ret;
343 : }
344 0 : break;
345 2944047 : case PT_TIMESPEC:
346 2944047 : if (!put_timespec64(&rts, p))
347 : return ret;
348 : break;
349 0 : case PT_OLD_TIMESPEC:
350 0 : if (!put_old_timespec32(&rts, p))
351 : return ret;
352 : break;
353 0 : default:
354 0 : BUG();
355 : }
356 : /*
357 : * If an application puts its timeval in read-only memory, we
358 : * don't want the Linux-specific update to the timeval to
359 : * cause a fault after the select has completed
360 : * successfully. However, because we're not updating the
361 : * timeval, we can't restart the system call.
362 : */
363 :
364 0 : sticky:
365 0 : if (ret == -ERESTARTNOHAND)
366 0 : ret = -EINTR;
367 : return ret;
368 : }
369 :
370 : /*
371 : * Scalable version of the fd_set.
372 : */
373 :
374 : typedef struct {
375 : unsigned long *in, *out, *ex;
376 : unsigned long *res_in, *res_out, *res_ex;
377 : } fd_set_bits;
378 :
379 : /*
380 : * How many longwords for "nr" bits?
381 : */
382 : #define FDS_BITPERLONG (8*sizeof(long))
383 : #define FDS_LONGS(nr) (((nr)+FDS_BITPERLONG-1)/FDS_BITPERLONG)
384 : #define FDS_BYTES(nr) (FDS_LONGS(nr)*sizeof(long))
385 :
386 : /*
387 : * Use "unsigned long" accesses to let user-mode fd_set's be long-aligned.
388 : */
389 : static inline
390 323430 : int get_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
391 : {
392 323430 : nr = FDS_BYTES(nr);
393 323430 : if (ufdset)
394 250888 : return copy_from_user(fdset, ufdset, nr) ? -EFAULT : 0;
395 :
396 197986 : memset(fdset, 0, nr);
397 197986 : return 0;
398 : }
399 :
400 : static inline unsigned long __must_check
401 323418 : set_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
402 : {
403 323418 : if (ufdset)
404 125440 : return __copy_to_user(ufdset, fdset, FDS_BYTES(nr));
405 : return 0;
406 : }
407 :
408 : static inline
409 323430 : void zero_fd_set(unsigned long nr, unsigned long *fdset)
410 : {
411 323430 : memset(fdset, 0, FDS_BYTES(nr));
412 323430 : }
413 :
414 : #define FDS_IN(fds, n) (fds->in + n)
415 : #define FDS_OUT(fds, n) (fds->out + n)
416 : #define FDS_EX(fds, n) (fds->ex + n)
417 :
418 : #define BITS(fds, n) (*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n))
419 :
420 107810 : static int max_select_fd(unsigned long n, fd_set_bits *fds)
421 : {
422 107810 : unsigned long *open_fds;
423 107810 : unsigned long set;
424 107810 : int max;
425 107810 : struct fdtable *fdt;
426 :
427 : /* handle last in-complete long-word first */
428 107810 : set = ~(~0UL << (n & (BITS_PER_LONG-1)));
429 107810 : n /= BITS_PER_LONG;
430 107810 : fdt = files_fdtable(current->files);
431 107810 : open_fds = fdt->open_fds + n;
432 107810 : max = 0;
433 107810 : if (set) {
434 106532 : set &= BITS(fds, n);
435 106532 : if (set) {
436 106532 : if (!(set & ~*open_fds))
437 106532 : goto get_max;
438 : return -EBADF;
439 : }
440 : }
441 107810 : while (n) {
442 0 : open_fds--;
443 0 : n--;
444 0 : set = BITS(fds, n);
445 0 : if (!set)
446 0 : continue;
447 0 : if (set & ~*open_fds)
448 : return -EBADF;
449 0 : if (max)
450 0 : continue;
451 0 : get_max:
452 597463 : do {
453 597463 : max++;
454 597463 : set >>= 1;
455 597463 : } while (set);
456 106532 : max += n * BITS_PER_LONG;
457 : }
458 :
459 : return max;
460 : }
461 :
462 : #define POLLIN_SET (EPOLLRDNORM | EPOLLRDBAND | EPOLLIN | EPOLLHUP | EPOLLERR |\
463 : EPOLLNVAL)
464 : #define POLLOUT_SET (EPOLLWRBAND | EPOLLWRNORM | EPOLLOUT | EPOLLERR |\
465 : EPOLLNVAL)
466 : #define POLLEX_SET (EPOLLPRI | EPOLLNVAL)
467 :
468 : static inline void wait_key_set(poll_table *wait, unsigned long in,
469 : unsigned long out, unsigned long bit,
470 : __poll_t ll_flag)
471 : {
472 245602 : wait->_key = POLLEX_SET | ll_flag;
473 245602 : if (in & bit)
474 243129 : wait->_key |= POLLIN_SET;
475 245602 : if (out & bit)
476 2472 : wait->_key |= POLLOUT_SET;
477 : }
478 :
479 107810 : static int do_select(int n, fd_set_bits *fds, struct timespec64 *end_time)
480 : {
481 107810 : ktime_t expire, *to = NULL;
482 107810 : struct poll_wqueues table;
483 107810 : poll_table *wait;
484 107810 : int retval, i, timed_out = 0;
485 107810 : u64 slack = 0;
486 107810 : __poll_t busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0;
487 107810 : unsigned long busy_start = 0;
488 :
489 107810 : rcu_read_lock();
490 107810 : retval = max_select_fd(n, fds);
491 107810 : rcu_read_unlock();
492 :
493 107810 : if (retval < 0)
494 : return retval;
495 107810 : n = retval;
496 :
497 107810 : poll_initwait(&table);
498 107810 : wait = &table.pt;
499 107810 : if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
500 7 : wait->_qproc = NULL;
501 7 : timed_out = 1;
502 : }
503 :
504 107810 : if (end_time && !timed_out)
505 86417 : slack = select_estimate_accuracy(end_time);
506 :
507 107810 : retval = 0;
508 210348 : for (;;) {
509 210348 : unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp;
510 210348 : bool can_busy_loop = false;
511 :
512 210348 : inp = fds->in; outp = fds->out; exp = fds->ex;
513 210348 : rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex;
514 :
515 418140 : for (i = 0; i < n; ++rinp, ++routp, ++rexp) {
516 207792 : unsigned long in, out, ex, all_bits, bit = 1, j;
517 207792 : unsigned long res_in = 0, res_out = 0, res_ex = 0;
518 207792 : __poll_t mask;
519 :
520 207792 : in = *inp++; out = *outp++; ex = *exp++;
521 207792 : all_bits = in | out | ex;
522 207792 : if (all_bits == 0) {
523 0 : i += BITS_PER_LONG;
524 0 : continue;
525 : }
526 :
527 1370667 : for (j = 0; j < BITS_PER_LONG; ++j, ++i, bit <<= 1) {
528 1370667 : struct fd f;
529 1370667 : if (i >= n)
530 : break;
531 1162875 : if (!(bit & all_bits))
532 917273 : continue;
533 245602 : mask = EPOLLNVAL;
534 245602 : f = fdget(i);
535 245602 : if (f.file) {
536 245602 : wait_key_set(wait, in, out, bit,
537 : busy_flag);
538 245602 : mask = vfs_poll(f.file, wait);
539 :
540 245602 : fdput(f);
541 : }
542 245602 : if ((mask & POLLIN_SET) && (in & bit)) {
543 23873 : res_in |= bit;
544 23873 : retval++;
545 23873 : wait->_qproc = NULL;
546 : }
547 245602 : if ((mask & POLLOUT_SET) && (out & bit)) {
548 2472 : res_out |= bit;
549 2472 : retval++;
550 2472 : wait->_qproc = NULL;
551 : }
552 245602 : if ((mask & POLLEX_SET) && (ex & bit)) {
553 0 : res_ex |= bit;
554 0 : retval++;
555 0 : wait->_qproc = NULL;
556 : }
557 : /* got something, stop busy polling */
558 245602 : if (retval) {
559 : can_busy_loop = false;
560 : busy_flag = 0;
561 :
562 : /*
563 : * only remember a returned
564 : * POLL_BUSY_LOOP if we asked for it
565 : */
566 219202 : } else if (busy_flag & mask)
567 0 : can_busy_loop = true;
568 :
569 : }
570 207792 : if (res_in)
571 23865 : *rinp = res_in;
572 207792 : if (res_out)
573 2472 : *routp = res_out;
574 207792 : if (res_ex)
575 0 : *rexp = res_ex;
576 207792 : cond_resched();
577 : }
578 210348 : wait->_qproc = NULL;
579 210348 : if (retval || timed_out || signal_pending(current))
580 : break;
581 102542 : if (table.error) {
582 : retval = table.error;
583 : break;
584 : }
585 :
586 : /* only if found POLL_BUSY_LOOP sockets && not out of time */
587 102542 : if (can_busy_loop && !need_resched()) {
588 0 : if (!busy_start) {
589 0 : busy_start = busy_loop_current_time();
590 0 : continue;
591 : }
592 0 : if (!busy_loop_timeout(busy_start))
593 0 : continue;
594 : }
595 102542 : busy_flag = 0;
596 :
597 : /*
598 : * If this is the first loop and we have a timeout
599 : * given, then we convert to ktime_t and set the to
600 : * pointer to the expiry value.
601 : */
602 102542 : if (end_time && !to) {
603 83636 : expire = timespec64_to_ktime(*end_time);
604 83636 : to = &expire;
605 : }
606 :
607 102542 : if (!poll_schedule_timeout(&table, TASK_INTERRUPTIBLE,
608 : to, slack))
609 81469 : timed_out = 1;
610 : }
611 :
612 107806 : poll_freewait(&table);
613 :
614 107806 : return retval;
615 : }
616 :
617 : /*
618 : * We can actually return ERESTARTSYS instead of EINTR, but I'd
619 : * like to be certain this leads to no problems. So I return
620 : * EINTR just for safety.
621 : *
622 : * Update: ERESTARTSYS breaks at least the xview clock binary, so
623 : * I'm trying ERESTARTNOHAND which restart only when you want to.
624 : */
625 107810 : int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
626 : fd_set __user *exp, struct timespec64 *end_time)
627 : {
628 107810 : fd_set_bits fds;
629 107810 : void *bits;
630 107810 : int ret, max_fds;
631 107810 : size_t size, alloc_size;
632 107810 : struct fdtable *fdt;
633 : /* Allocate small arguments on the stack to save memory and be faster */
634 107810 : long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
635 :
636 107810 : ret = -EINVAL;
637 107810 : if (n < 0)
638 0 : goto out_nofds;
639 :
640 : /* max_fds can increase, so grab it once to avoid race */
641 107810 : rcu_read_lock();
642 107810 : fdt = files_fdtable(current->files);
643 107810 : max_fds = fdt->max_fds;
644 107810 : rcu_read_unlock();
645 107810 : if (n > max_fds)
646 : n = max_fds;
647 :
648 : /*
649 : * We need 6 bitmaps (in/out/ex for both incoming and outgoing),
650 : * since we used fdset we need to allocate memory in units of
651 : * long-words.
652 : */
653 107810 : size = FDS_BYTES(n);
654 107810 : bits = stack_fds;
655 107810 : if (size > sizeof(stack_fds) / 6) {
656 : /* Not enough space in on-stack array; must use kmalloc */
657 0 : ret = -ENOMEM;
658 0 : if (size > (SIZE_MAX / 6))
659 : goto out_nofds;
660 :
661 0 : alloc_size = 6 * size;
662 0 : bits = kvmalloc(alloc_size, GFP_KERNEL);
663 0 : if (!bits)
664 0 : goto out_nofds;
665 : }
666 107810 : fds.in = bits;
667 107810 : fds.out = bits + size;
668 107810 : fds.ex = bits + 2*size;
669 107810 : fds.res_in = bits + 3*size;
670 107810 : fds.res_out = bits + 4*size;
671 107810 : fds.res_ex = bits + 5*size;
672 :
673 215620 : if ((ret = get_fd_set(n, inp, fds.in)) ||
674 215620 : (ret = get_fd_set(n, outp, fds.out)) ||
675 107810 : (ret = get_fd_set(n, exp, fds.ex)))
676 0 : goto out;
677 107810 : zero_fd_set(n, fds.res_in);
678 107810 : zero_fd_set(n, fds.res_out);
679 107810 : zero_fd_set(n, fds.res_ex);
680 :
681 107810 : ret = do_select(n, &fds, end_time);
682 :
683 107806 : if (ret < 0)
684 0 : goto out;
685 107806 : if (!ret) {
686 81469 : ret = -ERESTARTNOHAND;
687 81469 : if (signal_pending(current))
688 0 : goto out;
689 : ret = 0;
690 : }
691 :
692 215612 : if (set_fd_set(n, inp, fds.res_in) ||
693 215612 : set_fd_set(n, outp, fds.res_out) ||
694 107806 : set_fd_set(n, exp, fds.res_ex))
695 : ret = -EFAULT;
696 :
697 107806 : out:
698 107806 : if (bits != stack_fds)
699 0 : kvfree(bits);
700 107806 : out_nofds:
701 107806 : return ret;
702 : }
703 :
704 0 : static int kern_select(int n, fd_set __user *inp, fd_set __user *outp,
705 : fd_set __user *exp, struct __kernel_old_timeval __user *tvp)
706 : {
707 0 : struct timespec64 end_time, *to = NULL;
708 0 : struct __kernel_old_timeval tv;
709 0 : int ret;
710 :
711 0 : if (tvp) {
712 0 : if (copy_from_user(&tv, tvp, sizeof(tv)))
713 : return -EFAULT;
714 :
715 0 : to = &end_time;
716 0 : if (poll_select_set_timeout(to,
717 0 : tv.tv_sec + (tv.tv_usec / USEC_PER_SEC),
718 0 : (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC))
719 : return -EINVAL;
720 : }
721 :
722 0 : ret = core_sys_select(n, inp, outp, exp, to);
723 0 : return poll_select_finish(&end_time, tvp, PT_TIMEVAL, ret);
724 : }
725 :
726 0 : SYSCALL_DEFINE5(select, int, n, fd_set __user *, inp, fd_set __user *, outp,
727 : fd_set __user *, exp, struct __kernel_old_timeval __user *, tvp)
728 : {
729 0 : return kern_select(n, inp, outp, exp, tvp);
730 : }
731 :
732 107810 : static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp,
733 : fd_set __user *exp, void __user *tsp,
734 : const sigset_t __user *sigmask, size_t sigsetsize,
735 : enum poll_time_type type)
736 : {
737 107810 : struct timespec64 ts, end_time, *to = NULL;
738 107810 : int ret;
739 :
740 107810 : if (tsp) {
741 86424 : switch (type) {
742 86424 : case PT_TIMESPEC:
743 86424 : if (get_timespec64(&ts, tsp))
744 : return -EFAULT;
745 : break;
746 0 : case PT_OLD_TIMESPEC:
747 0 : if (get_old_timespec32(&ts, tsp))
748 : return -EFAULT;
749 : break;
750 0 : default:
751 0 : BUG();
752 : }
753 :
754 86424 : to = &end_time;
755 86424 : if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
756 : return -EINVAL;
757 : }
758 :
759 107810 : ret = set_user_sigmask(sigmask, sigsetsize);
760 107810 : if (ret)
761 0 : return ret;
762 :
763 107810 : ret = core_sys_select(n, inp, outp, exp, to);
764 107806 : return poll_select_finish(&end_time, tsp, type, ret);
765 : }
766 :
767 : /*
768 : * Most architectures can't handle 7-argument syscalls. So we provide a
769 : * 6-argument version where the sixth argument is a pointer to a structure
770 : * which has a pointer to the sigset_t itself followed by a size_t containing
771 : * the sigset size.
772 : */
773 : struct sigset_argpack {
774 : sigset_t __user *p;
775 : size_t size;
776 : };
777 :
778 107810 : static inline int get_sigset_argpack(struct sigset_argpack *to,
779 : struct sigset_argpack __user *from)
780 : {
781 : // the path is hot enough for overhead of copy_from_user() to matter
782 107810 : if (from) {
783 1124 : if (!user_read_access_begin(from, sizeof(*from)))
784 : return -EFAULT;
785 1124 : unsafe_get_user(to->p, &from->p, Efault);
786 1124 : unsafe_get_user(to->size, &from->size, Efault);
787 1124 : user_read_access_end();
788 : }
789 : return 0;
790 0 : Efault:
791 0 : user_access_end();
792 0 : return -EFAULT;
793 : }
794 :
795 215620 : SYSCALL_DEFINE6(pselect6, int, n, fd_set __user *, inp, fd_set __user *, outp,
796 : fd_set __user *, exp, struct __kernel_timespec __user *, tsp,
797 : void __user *, sig)
798 : {
799 107810 : struct sigset_argpack x = {NULL, 0};
800 :
801 107810 : if (get_sigset_argpack(&x, sig))
802 : return -EFAULT;
803 :
804 107810 : return do_pselect(n, inp, outp, exp, tsp, x.p, x.size, PT_TIMESPEC);
805 : }
806 :
807 : #if defined(CONFIG_COMPAT_32BIT_TIME) && !defined(CONFIG_64BIT)
808 :
809 : SYSCALL_DEFINE6(pselect6_time32, int, n, fd_set __user *, inp, fd_set __user *, outp,
810 : fd_set __user *, exp, struct old_timespec32 __user *, tsp,
811 : void __user *, sig)
812 : {
813 : struct sigset_argpack x = {NULL, 0};
814 :
815 : if (get_sigset_argpack(&x, sig))
816 : return -EFAULT;
817 :
818 : return do_pselect(n, inp, outp, exp, tsp, x.p, x.size, PT_OLD_TIMESPEC);
819 : }
820 :
821 : #endif
822 :
823 : #ifdef __ARCH_WANT_SYS_OLD_SELECT
824 : struct sel_arg_struct {
825 : unsigned long n;
826 : fd_set __user *inp, *outp, *exp;
827 : struct __kernel_old_timeval __user *tvp;
828 : };
829 :
830 : SYSCALL_DEFINE1(old_select, struct sel_arg_struct __user *, arg)
831 : {
832 : struct sel_arg_struct a;
833 :
834 : if (copy_from_user(&a, arg, sizeof(a)))
835 : return -EFAULT;
836 : return kern_select(a.n, a.inp, a.outp, a.exp, a.tvp);
837 : }
838 : #endif
839 :
840 : struct poll_list {
841 : struct poll_list *next;
842 : int len;
843 : struct pollfd entries[];
844 : };
845 :
846 : #define POLLFD_PER_PAGE ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd))
847 :
848 : /*
849 : * Fish for pollable events on the pollfd->fd file descriptor. We're only
850 : * interested in events matching the pollfd->events mask, and the result
851 : * matching that mask is both recorded in pollfd->revents and returned. The
852 : * pwait poll_table will be used by the fd-provided poll handler for waiting,
853 : * if pwait->_qproc is non-NULL.
854 : */
855 18092191 : static inline __poll_t do_pollfd(struct pollfd *pollfd, poll_table *pwait,
856 : bool *can_busy_poll,
857 : __poll_t busy_flag)
858 : {
859 18092191 : int fd = pollfd->fd;
860 18092191 : __poll_t mask = 0, filter;
861 18092191 : struct fd f;
862 :
863 18092191 : if (fd < 0)
864 125594 : goto out;
865 17966597 : mask = EPOLLNVAL;
866 17966597 : f = fdget(fd);
867 17966025 : if (!f.file)
868 3529 : goto out;
869 :
870 : /* userland u16 ->events contains POLL... bitmap */
871 17962496 : filter = demangle_poll(pollfd->events) | EPOLLERR | EPOLLHUP;
872 17962496 : pwait->_key = filter | busy_flag;
873 17962496 : mask = vfs_poll(f.file, pwait);
874 17963340 : if (mask & busy_flag)
875 0 : *can_busy_poll = true;
876 17963340 : mask &= filter; /* Mask out unneeded events. */
877 17963340 : fdput(f);
878 :
879 18092462 : out:
880 : /* ... and so does ->revents */
881 18092462 : pollfd->revents = mangle_poll(mask);
882 18092462 : return mask;
883 : }
884 :
885 7863928 : static int do_poll(struct poll_list *list, struct poll_wqueues *wait,
886 : struct timespec64 *end_time)
887 : {
888 7863928 : poll_table* pt = &wait->pt;
889 7863928 : ktime_t expire, *to = NULL;
890 7863928 : int timed_out = 0, count = 0;
891 7863928 : u64 slack = 0;
892 7863928 : __poll_t busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0;
893 7863928 : unsigned long busy_start = 0;
894 :
895 : /* Optimise the no-wait case */
896 7863928 : if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
897 3261262 : pt->_qproc = NULL;
898 3261262 : timed_out = 1;
899 : }
900 :
901 7863928 : if (end_time && !timed_out)
902 3134530 : slack = select_estimate_accuracy(end_time);
903 :
904 12316140 : for (;;) {
905 12316140 : struct poll_list *walk;
906 12316140 : bool can_busy_loop = false;
907 :
908 24634172 : for (walk = list; walk != NULL; walk = walk->next) {
909 12318064 : struct pollfd * pfd, * pfd_end;
910 :
911 12318064 : pfd = walk->entries;
912 12318064 : pfd_end = pfd + walk->len;
913 30409771 : for (; pfd != pfd_end; pfd++) {
914 : /*
915 : * Fish for events. If we found one, record it
916 : * and kill poll_table->_qproc, so we don't
917 : * needlessly register any other waiters after
918 : * this. They'll get immediately deregistered
919 : * when we break out and return.
920 : */
921 18091739 : if (do_pollfd(pfd, pt, &can_busy_loop,
922 : busy_flag)) {
923 4548837 : count++;
924 4548837 : pt->_qproc = NULL;
925 : /* found something, stop busy polling */
926 4548837 : busy_flag = 0;
927 4548837 : can_busy_loop = false;
928 : }
929 : }
930 : }
931 : /*
932 : * All waiters have already been registered, so don't provide
933 : * a poll_table->_qproc to them on the next loop iteration.
934 : */
935 12316108 : pt->_qproc = NULL;
936 12316108 : if (!count) {
937 7778442 : count = wait->error;
938 7778442 : if (signal_pending(current))
939 1376 : count = -ERESTARTNOHAND;
940 : }
941 12316008 : if (count || timed_out)
942 : break;
943 :
944 : /* only if found POLL_BUSY_LOOP sockets && not out of time */
945 4452147 : if (can_busy_loop && !need_resched()) {
946 0 : if (!busy_start) {
947 0 : busy_start = busy_loop_current_time();
948 0 : continue;
949 : }
950 0 : if (!busy_loop_timeout(busy_start))
951 0 : continue;
952 : }
953 4452147 : busy_flag = 0;
954 :
955 : /*
956 : * If this is the first loop and we have a timeout
957 : * given, then we convert to ktime_t and set the to
958 : * pointer to the expiry value.
959 : */
960 4452147 : if (end_time && !to) {
961 3081328 : expire = timespec64_to_ktime(*end_time);
962 3081328 : to = &expire;
963 : }
964 :
965 4452147 : if (!poll_schedule_timeout(wait, TASK_INTERRUPTIBLE, to, slack))
966 175702 : timed_out = 1;
967 : }
968 7863861 : return count;
969 : }
970 :
971 : #define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \
972 : sizeof(struct pollfd))
973 :
974 7863908 : static int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,
975 : struct timespec64 *end_time)
976 : {
977 7863908 : struct poll_wqueues table;
978 7863908 : int err = -EFAULT, fdcount, len;
979 : /* Allocate small arguments on the stack to save memory and be
980 : faster - use long to make sure the buffer is aligned properly
981 : on 64 bit archs to avoid unaligned access */
982 7863908 : long stack_pps[POLL_STACK_ALLOC/sizeof(long)];
983 7863908 : struct poll_list *const head = (struct poll_list *)stack_pps;
984 7863908 : struct poll_list *walk = head;
985 7863908 : unsigned long todo = nfds;
986 :
987 7863908 : if (nfds > rlimit(RLIMIT_NOFILE))
988 : return -EINVAL;
989 :
990 7863908 : len = min_t(unsigned int, nfds, N_STACK_PPS);
991 7864966 : for (;;) {
992 7864966 : walk->next = NULL;
993 7864966 : walk->len = len;
994 7864966 : if (!len)
995 : break;
996 :
997 7863859 : if (copy_from_user(walk->entries, ufds + nfds-todo,
998 7863821 : sizeof(struct pollfd) * walk->len))
999 0 : goto out_fds;
1000 :
1001 7863859 : todo -= walk->len;
1002 7863859 : if (!todo)
1003 : break;
1004 :
1005 1069 : len = min(todo, POLLFD_PER_PAGE);
1006 1069 : walk = walk->next = kmalloc(struct_size(walk, entries, len),
1007 : GFP_KERNEL);
1008 1069 : if (!walk) {
1009 0 : err = -ENOMEM;
1010 0 : goto out_fds;
1011 : }
1012 : }
1013 :
1014 7863935 : poll_initwait(&table);
1015 7863935 : fdcount = do_poll(head, &table, end_time);
1016 7863840 : poll_freewait(&table);
1017 :
1018 7863929 : if (!user_write_access_begin(ufds, nfds * sizeof(*ufds)))
1019 0 : goto out_fds;
1020 :
1021 15728377 : for (walk = head; walk; walk = walk->next) {
1022 7865051 : struct pollfd *fds = walk->entries;
1023 7865051 : int j;
1024 :
1025 19339328 : for (j = walk->len; j; fds++, ufds++, j--)
1026 11474929 : unsafe_put_user(fds->revents, &ufds->revents, Efault);
1027 : }
1028 7863326 : user_write_access_end();
1029 :
1030 7863326 : err = fdcount;
1031 7864040 : out_fds:
1032 7864040 : walk = head->next;
1033 7865106 : while (walk) {
1034 1069 : struct poll_list *pos = walk;
1035 1069 : walk = walk->next;
1036 1069 : kfree(pos);
1037 : }
1038 :
1039 : return err;
1040 :
1041 0 : Efault:
1042 0 : user_write_access_end();
1043 0 : err = -EFAULT;
1044 0 : goto out_fds;
1045 : }
1046 :
1047 0 : static long do_restart_poll(struct restart_block *restart_block)
1048 : {
1049 0 : struct pollfd __user *ufds = restart_block->poll.ufds;
1050 0 : int nfds = restart_block->poll.nfds;
1051 0 : struct timespec64 *to = NULL, end_time;
1052 0 : int ret;
1053 :
1054 0 : if (restart_block->poll.has_timeout) {
1055 0 : end_time.tv_sec = restart_block->poll.tv_sec;
1056 0 : end_time.tv_nsec = restart_block->poll.tv_nsec;
1057 0 : to = &end_time;
1058 : }
1059 :
1060 0 : ret = do_sys_poll(ufds, nfds, to);
1061 :
1062 0 : if (ret == -ERESTARTNOHAND)
1063 0 : ret = set_restart_fn(restart_block, do_restart_poll);
1064 :
1065 0 : return ret;
1066 : }
1067 :
1068 7869718 : SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds,
1069 : int, timeout_msecs)
1070 : {
1071 3934857 : struct timespec64 end_time, *to = NULL;
1072 3934857 : int ret;
1073 :
1074 3934857 : if (timeout_msecs >= 0) {
1075 3319372 : to = &end_time;
1076 3319372 : poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC,
1077 3319372 : NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC));
1078 : }
1079 :
1080 3934857 : ret = do_sys_poll(ufds, nfds, to);
1081 :
1082 3934844 : if (ret == -ERESTARTNOHAND) {
1083 1115 : struct restart_block *restart_block;
1084 :
1085 1115 : restart_block = ¤t->restart_block;
1086 1115 : restart_block->poll.ufds = ufds;
1087 1115 : restart_block->poll.nfds = nfds;
1088 :
1089 1115 : if (timeout_msecs >= 0) {
1090 1115 : restart_block->poll.tv_sec = end_time.tv_sec;
1091 1115 : restart_block->poll.tv_nsec = end_time.tv_nsec;
1092 1115 : restart_block->poll.has_timeout = 1;
1093 : } else
1094 0 : restart_block->poll.has_timeout = 0;
1095 :
1096 1115 : ret = set_restart_fn(restart_block, do_restart_poll);
1097 : }
1098 3934844 : return ret;
1099 : }
1100 :
1101 7858368 : SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds,
1102 : struct __kernel_timespec __user *, tsp, const sigset_t __user *, sigmask,
1103 : size_t, sigsetsize)
1104 : {
1105 3929178 : struct timespec64 ts, end_time, *to = NULL;
1106 3929178 : int ret;
1107 :
1108 3929178 : if (tsp) {
1109 3076451 : if (get_timespec64(&ts, tsp))
1110 : return -EFAULT;
1111 :
1112 3076449 : to = &end_time;
1113 3076449 : if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
1114 : return -EINVAL;
1115 : }
1116 :
1117 3929145 : ret = set_user_sigmask(sigmask, sigsetsize);
1118 3929120 : if (ret)
1119 0 : return ret;
1120 :
1121 3929120 : ret = do_sys_poll(ufds, nfds, to);
1122 3929148 : return poll_select_finish(&end_time, tsp, PT_TIMESPEC, ret);
1123 : }
1124 :
1125 : #if defined(CONFIG_COMPAT_32BIT_TIME) && !defined(CONFIG_64BIT)
1126 :
1127 : SYSCALL_DEFINE5(ppoll_time32, struct pollfd __user *, ufds, unsigned int, nfds,
1128 : struct old_timespec32 __user *, tsp, const sigset_t __user *, sigmask,
1129 : size_t, sigsetsize)
1130 : {
1131 : struct timespec64 ts, end_time, *to = NULL;
1132 : int ret;
1133 :
1134 : if (tsp) {
1135 : if (get_old_timespec32(&ts, tsp))
1136 : return -EFAULT;
1137 :
1138 : to = &end_time;
1139 : if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
1140 : return -EINVAL;
1141 : }
1142 :
1143 : ret = set_user_sigmask(sigmask, sigsetsize);
1144 : if (ret)
1145 : return ret;
1146 :
1147 : ret = do_sys_poll(ufds, nfds, to);
1148 : return poll_select_finish(&end_time, tsp, PT_OLD_TIMESPEC, ret);
1149 : }
1150 : #endif
1151 :
1152 : #ifdef CONFIG_COMPAT
1153 : #define __COMPAT_NFDBITS (8 * sizeof(compat_ulong_t))
1154 :
1155 : /*
1156 : * Ooo, nasty. We need here to frob 32-bit unsigned longs to
1157 : * 64-bit unsigned longs.
1158 : */
1159 : static
1160 0 : int compat_get_fd_set(unsigned long nr, compat_ulong_t __user *ufdset,
1161 : unsigned long *fdset)
1162 : {
1163 0 : if (ufdset) {
1164 0 : return compat_get_bitmap(fdset, ufdset, nr);
1165 : } else {
1166 0 : zero_fd_set(nr, fdset);
1167 0 : return 0;
1168 : }
1169 : }
1170 :
1171 : static
1172 : int compat_set_fd_set(unsigned long nr, compat_ulong_t __user *ufdset,
1173 : unsigned long *fdset)
1174 : {
1175 0 : if (!ufdset)
1176 : return 0;
1177 0 : return compat_put_bitmap(ufdset, fdset, nr);
1178 : }
1179 :
1180 :
1181 : /*
1182 : * This is a virtual copy of sys_select from fs/select.c and probably
1183 : * should be compared to it from time to time
1184 : */
1185 :
1186 : /*
1187 : * We can actually return ERESTARTSYS instead of EINTR, but I'd
1188 : * like to be certain this leads to no problems. So I return
1189 : * EINTR just for safety.
1190 : *
1191 : * Update: ERESTARTSYS breaks at least the xview clock binary, so
1192 : * I'm trying ERESTARTNOHAND which restart only when you want to.
1193 : */
1194 0 : static int compat_core_sys_select(int n, compat_ulong_t __user *inp,
1195 : compat_ulong_t __user *outp, compat_ulong_t __user *exp,
1196 : struct timespec64 *end_time)
1197 : {
1198 0 : fd_set_bits fds;
1199 0 : void *bits;
1200 0 : int size, max_fds, ret = -EINVAL;
1201 0 : struct fdtable *fdt;
1202 0 : long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
1203 :
1204 0 : if (n < 0)
1205 0 : goto out_nofds;
1206 :
1207 : /* max_fds can increase, so grab it once to avoid race */
1208 0 : rcu_read_lock();
1209 0 : fdt = files_fdtable(current->files);
1210 0 : max_fds = fdt->max_fds;
1211 0 : rcu_read_unlock();
1212 0 : if (n > max_fds)
1213 : n = max_fds;
1214 :
1215 : /*
1216 : * We need 6 bitmaps (in/out/ex for both incoming and outgoing),
1217 : * since we used fdset we need to allocate memory in units of
1218 : * long-words.
1219 : */
1220 0 : size = FDS_BYTES(n);
1221 0 : bits = stack_fds;
1222 0 : if (size > sizeof(stack_fds) / 6) {
1223 0 : bits = kmalloc_array(6, size, GFP_KERNEL);
1224 0 : ret = -ENOMEM;
1225 0 : if (!bits)
1226 0 : goto out_nofds;
1227 : }
1228 0 : fds.in = (unsigned long *) bits;
1229 0 : fds.out = (unsigned long *) (bits + size);
1230 0 : fds.ex = (unsigned long *) (bits + 2*size);
1231 0 : fds.res_in = (unsigned long *) (bits + 3*size);
1232 0 : fds.res_out = (unsigned long *) (bits + 4*size);
1233 0 : fds.res_ex = (unsigned long *) (bits + 5*size);
1234 :
1235 0 : if ((ret = compat_get_fd_set(n, inp, fds.in)) ||
1236 0 : (ret = compat_get_fd_set(n, outp, fds.out)) ||
1237 0 : (ret = compat_get_fd_set(n, exp, fds.ex)))
1238 0 : goto out;
1239 0 : zero_fd_set(n, fds.res_in);
1240 0 : zero_fd_set(n, fds.res_out);
1241 0 : zero_fd_set(n, fds.res_ex);
1242 :
1243 0 : ret = do_select(n, &fds, end_time);
1244 :
1245 0 : if (ret < 0)
1246 0 : goto out;
1247 0 : if (!ret) {
1248 0 : ret = -ERESTARTNOHAND;
1249 0 : if (signal_pending(current))
1250 0 : goto out;
1251 : ret = 0;
1252 : }
1253 :
1254 0 : if (compat_set_fd_set(n, inp, fds.res_in) ||
1255 0 : compat_set_fd_set(n, outp, fds.res_out) ||
1256 0 : compat_set_fd_set(n, exp, fds.res_ex))
1257 : ret = -EFAULT;
1258 0 : out:
1259 0 : if (bits != stack_fds)
1260 0 : kfree(bits);
1261 0 : out_nofds:
1262 0 : return ret;
1263 : }
1264 :
1265 0 : static int do_compat_select(int n, compat_ulong_t __user *inp,
1266 : compat_ulong_t __user *outp, compat_ulong_t __user *exp,
1267 : struct old_timeval32 __user *tvp)
1268 : {
1269 0 : struct timespec64 end_time, *to = NULL;
1270 0 : struct old_timeval32 tv;
1271 0 : int ret;
1272 :
1273 0 : if (tvp) {
1274 0 : if (copy_from_user(&tv, tvp, sizeof(tv)))
1275 : return -EFAULT;
1276 :
1277 0 : to = &end_time;
1278 0 : if (poll_select_set_timeout(to,
1279 0 : tv.tv_sec + (tv.tv_usec / USEC_PER_SEC),
1280 0 : (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC))
1281 : return -EINVAL;
1282 : }
1283 :
1284 0 : ret = compat_core_sys_select(n, inp, outp, exp, to);
1285 0 : return poll_select_finish(&end_time, tvp, PT_OLD_TIMEVAL, ret);
1286 : }
1287 :
1288 0 : COMPAT_SYSCALL_DEFINE5(select, int, n, compat_ulong_t __user *, inp,
1289 : compat_ulong_t __user *, outp, compat_ulong_t __user *, exp,
1290 : struct old_timeval32 __user *, tvp)
1291 : {
1292 0 : return do_compat_select(n, inp, outp, exp, tvp);
1293 : }
1294 :
1295 : struct compat_sel_arg_struct {
1296 : compat_ulong_t n;
1297 : compat_uptr_t inp;
1298 : compat_uptr_t outp;
1299 : compat_uptr_t exp;
1300 : compat_uptr_t tvp;
1301 : };
1302 :
1303 0 : COMPAT_SYSCALL_DEFINE1(old_select, struct compat_sel_arg_struct __user *, arg)
1304 : {
1305 0 : struct compat_sel_arg_struct a;
1306 :
1307 0 : if (copy_from_user(&a, arg, sizeof(a)))
1308 : return -EFAULT;
1309 0 : return do_compat_select(a.n, compat_ptr(a.inp), compat_ptr(a.outp),
1310 0 : compat_ptr(a.exp), compat_ptr(a.tvp));
1311 : }
1312 :
1313 0 : static long do_compat_pselect(int n, compat_ulong_t __user *inp,
1314 : compat_ulong_t __user *outp, compat_ulong_t __user *exp,
1315 : void __user *tsp, compat_sigset_t __user *sigmask,
1316 : compat_size_t sigsetsize, enum poll_time_type type)
1317 : {
1318 0 : struct timespec64 ts, end_time, *to = NULL;
1319 0 : int ret;
1320 :
1321 0 : if (tsp) {
1322 0 : switch (type) {
1323 0 : case PT_OLD_TIMESPEC:
1324 0 : if (get_old_timespec32(&ts, tsp))
1325 : return -EFAULT;
1326 : break;
1327 0 : case PT_TIMESPEC:
1328 0 : if (get_timespec64(&ts, tsp))
1329 : return -EFAULT;
1330 : break;
1331 0 : default:
1332 0 : BUG();
1333 : }
1334 :
1335 0 : to = &end_time;
1336 0 : if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
1337 : return -EINVAL;
1338 : }
1339 :
1340 0 : ret = set_compat_user_sigmask(sigmask, sigsetsize);
1341 0 : if (ret)
1342 0 : return ret;
1343 :
1344 0 : ret = compat_core_sys_select(n, inp, outp, exp, to);
1345 0 : return poll_select_finish(&end_time, tsp, type, ret);
1346 : }
1347 :
1348 : struct compat_sigset_argpack {
1349 : compat_uptr_t p;
1350 : compat_size_t size;
1351 : };
1352 0 : static inline int get_compat_sigset_argpack(struct compat_sigset_argpack *to,
1353 : struct compat_sigset_argpack __user *from)
1354 : {
1355 0 : if (from) {
1356 0 : if (!user_read_access_begin(from, sizeof(*from)))
1357 : return -EFAULT;
1358 0 : unsafe_get_user(to->p, &from->p, Efault);
1359 0 : unsafe_get_user(to->size, &from->size, Efault);
1360 0 : user_read_access_end();
1361 : }
1362 : return 0;
1363 0 : Efault:
1364 0 : user_access_end();
1365 0 : return -EFAULT;
1366 : }
1367 :
1368 0 : COMPAT_SYSCALL_DEFINE6(pselect6_time64, int, n, compat_ulong_t __user *, inp,
1369 : compat_ulong_t __user *, outp, compat_ulong_t __user *, exp,
1370 : struct __kernel_timespec __user *, tsp, void __user *, sig)
1371 : {
1372 0 : struct compat_sigset_argpack x = {0, 0};
1373 :
1374 0 : if (get_compat_sigset_argpack(&x, sig))
1375 : return -EFAULT;
1376 :
1377 0 : return do_compat_pselect(n, inp, outp, exp, tsp, compat_ptr(x.p),
1378 : x.size, PT_TIMESPEC);
1379 : }
1380 :
1381 : #if defined(CONFIG_COMPAT_32BIT_TIME)
1382 :
1383 0 : COMPAT_SYSCALL_DEFINE6(pselect6_time32, int, n, compat_ulong_t __user *, inp,
1384 : compat_ulong_t __user *, outp, compat_ulong_t __user *, exp,
1385 : struct old_timespec32 __user *, tsp, void __user *, sig)
1386 : {
1387 0 : struct compat_sigset_argpack x = {0, 0};
1388 :
1389 0 : if (get_compat_sigset_argpack(&x, sig))
1390 : return -EFAULT;
1391 :
1392 0 : return do_compat_pselect(n, inp, outp, exp, tsp, compat_ptr(x.p),
1393 : x.size, PT_OLD_TIMESPEC);
1394 : }
1395 :
1396 : #endif
1397 :
1398 : #if defined(CONFIG_COMPAT_32BIT_TIME)
1399 0 : COMPAT_SYSCALL_DEFINE5(ppoll_time32, struct pollfd __user *, ufds,
1400 : unsigned int, nfds, struct old_timespec32 __user *, tsp,
1401 : const compat_sigset_t __user *, sigmask, compat_size_t, sigsetsize)
1402 : {
1403 0 : struct timespec64 ts, end_time, *to = NULL;
1404 0 : int ret;
1405 :
1406 0 : if (tsp) {
1407 0 : if (get_old_timespec32(&ts, tsp))
1408 : return -EFAULT;
1409 :
1410 0 : to = &end_time;
1411 0 : if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
1412 : return -EINVAL;
1413 : }
1414 :
1415 0 : ret = set_compat_user_sigmask(sigmask, sigsetsize);
1416 0 : if (ret)
1417 0 : return ret;
1418 :
1419 0 : ret = do_sys_poll(ufds, nfds, to);
1420 0 : return poll_select_finish(&end_time, tsp, PT_OLD_TIMESPEC, ret);
1421 : }
1422 : #endif
1423 :
1424 : /* New compat syscall for 64 bit time_t*/
1425 0 : COMPAT_SYSCALL_DEFINE5(ppoll_time64, struct pollfd __user *, ufds,
1426 : unsigned int, nfds, struct __kernel_timespec __user *, tsp,
1427 : const compat_sigset_t __user *, sigmask, compat_size_t, sigsetsize)
1428 : {
1429 0 : struct timespec64 ts, end_time, *to = NULL;
1430 0 : int ret;
1431 :
1432 0 : if (tsp) {
1433 0 : if (get_timespec64(&ts, tsp))
1434 : return -EFAULT;
1435 :
1436 0 : to = &end_time;
1437 0 : if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
1438 : return -EINVAL;
1439 : }
1440 :
1441 0 : ret = set_compat_user_sigmask(sigmask, sigsetsize);
1442 0 : if (ret)
1443 0 : return ret;
1444 :
1445 0 : ret = do_sys_poll(ufds, nfds, to);
1446 0 : return poll_select_finish(&end_time, tsp, PT_TIMESPEC, ret);
1447 : }
1448 :
1449 : #endif
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