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Commit | Line | Data |
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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
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 | ||
022a1692 | 18 | #include <linux/kernel.h> |
3f07c014 IM |
19 | #include <linux/sched/signal.h> |
20 | #include <linux/sched/rt.h> | |
1da177e4 | 21 | #include <linux/syscalls.h> |
630d9c47 | 22 | #include <linux/export.h> |
1da177e4 | 23 | #include <linux/slab.h> |
1da177e4 LT |
24 | #include <linux/poll.h> |
25 | #include <linux/personality.h> /* for STICKY_TIMEOUTS */ | |
26 | #include <linux/file.h> | |
9f3acc31 | 27 | #include <linux/fdtable.h> |
1da177e4 | 28 | #include <linux/fs.h> |
b835996f | 29 | #include <linux/rcupdate.h> |
8ff3e8e8 | 30 | #include <linux/hrtimer.h> |
9745cdb3 | 31 | #include <linux/freezer.h> |
076bb0c8 | 32 | #include <net/busy_poll.h> |
2d19309c | 33 | #include <linux/vmalloc.h> |
1da177e4 | 34 | |
7c0f6ba6 | 35 | #include <linux/uaccess.h> |
1da177e4 | 36 | |
3deb642f CH |
37 | __poll_t vfs_poll(struct file *file, struct poll_table_struct *pt) |
38 | { | |
39 | if (file->f_op->poll) { | |
40 | return file->f_op->poll(file, pt); | |
41 | } else if (file_has_poll_mask(file)) { | |
42 | unsigned int events = poll_requested_events(pt); | |
43 | struct wait_queue_head *head; | |
44 | ||
45 | if (pt && pt->_qproc) { | |
46 | head = file->f_op->get_poll_head(file, events); | |
47 | if (!head) | |
48 | return DEFAULT_POLLMASK; | |
49 | if (IS_ERR(head)) | |
50 | return EPOLLERR; | |
51 | pt->_qproc(file, head, pt); | |
52 | } | |
53 | ||
54 | return file->f_op->poll_mask(file, events); | |
55 | } else { | |
56 | return DEFAULT_POLLMASK; | |
57 | } | |
58 | } | |
59 | EXPORT_SYMBOL_GPL(vfs_poll); | |
90d6e24a AV |
60 | |
61 | /* | |
62 | * Estimate expected accuracy in ns from a timeval. | |
63 | * | |
64 | * After quite a bit of churning around, we've settled on | |
65 | * a simple thing of taking 0.1% of the timeout as the | |
66 | * slack, with a cap of 100 msec. | |
67 | * "nice" tasks get a 0.5% slack instead. | |
68 | * | |
69 | * Consider this comment an open invitation to come up with even | |
70 | * better solutions.. | |
71 | */ | |
72 | ||
5ae87e79 GK |
73 | #define MAX_SLACK (100 * NSEC_PER_MSEC) |
74 | ||
766b9f92 | 75 | static long __estimate_accuracy(struct timespec64 *tv) |
90d6e24a | 76 | { |
96d2ab48 | 77 | long slack; |
90d6e24a AV |
78 | int divfactor = 1000; |
79 | ||
5ae87e79 GK |
80 | if (tv->tv_sec < 0) |
81 | return 0; | |
82 | ||
4ce105d3 | 83 | if (task_nice(current) > 0) |
90d6e24a AV |
84 | divfactor = divfactor / 5; |
85 | ||
5ae87e79 GK |
86 | if (tv->tv_sec > MAX_SLACK / (NSEC_PER_SEC/divfactor)) |
87 | return MAX_SLACK; | |
88 | ||
90d6e24a AV |
89 | slack = tv->tv_nsec / divfactor; |
90 | slack += tv->tv_sec * (NSEC_PER_SEC/divfactor); | |
91 | ||
5ae87e79 GK |
92 | if (slack > MAX_SLACK) |
93 | return MAX_SLACK; | |
96d2ab48 | 94 | |
90d6e24a AV |
95 | return slack; |
96 | } | |
97 | ||
766b9f92 | 98 | u64 select_estimate_accuracy(struct timespec64 *tv) |
90d6e24a | 99 | { |
da8b44d5 | 100 | u64 ret; |
766b9f92 | 101 | struct timespec64 now; |
90d6e24a AV |
102 | |
103 | /* | |
104 | * Realtime tasks get a slack of 0 for obvious reasons. | |
105 | */ | |
106 | ||
4ce105d3 | 107 | if (rt_task(current)) |
90d6e24a AV |
108 | return 0; |
109 | ||
766b9f92 DD |
110 | ktime_get_ts64(&now); |
111 | now = timespec64_sub(*tv, now); | |
90d6e24a AV |
112 | ret = __estimate_accuracy(&now); |
113 | if (ret < current->timer_slack_ns) | |
114 | return current->timer_slack_ns; | |
115 | return ret; | |
116 | } | |
117 | ||
118 | ||
119 | ||
1da177e4 LT |
120 | struct poll_table_page { |
121 | struct poll_table_page * next; | |
122 | struct poll_table_entry * entry; | |
123 | struct poll_table_entry entries[0]; | |
124 | }; | |
125 | ||
126 | #define POLL_TABLE_FULL(table) \ | |
127 | ((unsigned long)((table)->entry+1) > PAGE_SIZE + (unsigned long)(table)) | |
128 | ||
129 | /* | |
130 | * Ok, Peter made a complicated, but straightforward multiple_wait() function. | |
131 | * I have rewritten this, taking some shortcuts: This code may not be easy to | |
132 | * follow, but it should be free of race-conditions, and it's practical. If you | |
133 | * understand what I'm doing here, then you understand how the linux | |
134 | * sleep/wakeup mechanism works. | |
135 | * | |
136 | * Two very simple procedures, poll_wait() and poll_freewait() make all the | |
137 | * work. poll_wait() is an inline-function defined in <linux/poll.h>, | |
138 | * as all select/poll functions have to call it to add an entry to the | |
139 | * poll table. | |
140 | */ | |
75c96f85 AB |
141 | static void __pollwait(struct file *filp, wait_queue_head_t *wait_address, |
142 | poll_table *p); | |
1da177e4 LT |
143 | |
144 | void poll_initwait(struct poll_wqueues *pwq) | |
145 | { | |
146 | init_poll_funcptr(&pwq->pt, __pollwait); | |
5f820f64 | 147 | pwq->polling_task = current; |
b2add73d | 148 | pwq->triggered = 0; |
1da177e4 LT |
149 | pwq->error = 0; |
150 | pwq->table = NULL; | |
70674f95 | 151 | pwq->inline_index = 0; |
1da177e4 | 152 | } |
1da177e4 LT |
153 | EXPORT_SYMBOL(poll_initwait); |
154 | ||
70674f95 AK |
155 | static void free_poll_entry(struct poll_table_entry *entry) |
156 | { | |
ccf6780d | 157 | remove_wait_queue(entry->wait_address, &entry->wait); |
70674f95 AK |
158 | fput(entry->filp); |
159 | } | |
160 | ||
1da177e4 LT |
161 | void poll_freewait(struct poll_wqueues *pwq) |
162 | { | |
163 | struct poll_table_page * p = pwq->table; | |
70674f95 AK |
164 | int i; |
165 | for (i = 0; i < pwq->inline_index; i++) | |
166 | free_poll_entry(pwq->inline_entries + i); | |
1da177e4 LT |
167 | while (p) { |
168 | struct poll_table_entry * entry; | |
169 | struct poll_table_page *old; | |
170 | ||
171 | entry = p->entry; | |
172 | do { | |
173 | entry--; | |
70674f95 | 174 | free_poll_entry(entry); |
1da177e4 LT |
175 | } while (entry > p->entries); |
176 | old = p; | |
177 | p = p->next; | |
178 | free_page((unsigned long) old); | |
179 | } | |
180 | } | |
1da177e4 LT |
181 | EXPORT_SYMBOL(poll_freewait); |
182 | ||
5f820f64 | 183 | static struct poll_table_entry *poll_get_entry(struct poll_wqueues *p) |
1da177e4 | 184 | { |
1da177e4 LT |
185 | struct poll_table_page *table = p->table; |
186 | ||
70674f95 AK |
187 | if (p->inline_index < N_INLINE_POLL_ENTRIES) |
188 | return p->inline_entries + p->inline_index++; | |
189 | ||
1da177e4 LT |
190 | if (!table || POLL_TABLE_FULL(table)) { |
191 | struct poll_table_page *new_table; | |
192 | ||
193 | new_table = (struct poll_table_page *) __get_free_page(GFP_KERNEL); | |
194 | if (!new_table) { | |
195 | p->error = -ENOMEM; | |
70674f95 | 196 | return NULL; |
1da177e4 LT |
197 | } |
198 | new_table->entry = new_table->entries; | |
199 | new_table->next = table; | |
200 | p->table = new_table; | |
201 | table = new_table; | |
202 | } | |
203 | ||
70674f95 AK |
204 | return table->entry++; |
205 | } | |
206 | ||
ac6424b9 | 207 | static int __pollwake(wait_queue_entry_t *wait, unsigned mode, int sync, void *key) |
5f820f64 TH |
208 | { |
209 | struct poll_wqueues *pwq = wait->private; | |
210 | DECLARE_WAITQUEUE(dummy_wait, pwq->polling_task); | |
211 | ||
212 | /* | |
213 | * Although this function is called under waitqueue lock, LOCK | |
214 | * doesn't imply write barrier and the users expect write | |
215 | * barrier semantics on wakeup functions. The following | |
216 | * smp_wmb() is equivalent to smp_wmb() in try_to_wake_up() | |
b92b8b35 | 217 | * and is paired with smp_store_mb() in poll_schedule_timeout. |
5f820f64 TH |
218 | */ |
219 | smp_wmb(); | |
220 | pwq->triggered = 1; | |
221 | ||
222 | /* | |
223 | * Perform the default wake up operation using a dummy | |
224 | * waitqueue. | |
225 | * | |
226 | * TODO: This is hacky but there currently is no interface to | |
227 | * pass in @sync. @sync is scheduled to be removed and once | |
228 | * that happens, wake_up_process() can be used directly. | |
229 | */ | |
230 | return default_wake_function(&dummy_wait, mode, sync, key); | |
231 | } | |
232 | ||
ac6424b9 | 233 | static int pollwake(wait_queue_entry_t *wait, unsigned mode, int sync, void *key) |
4938d7e0 ED |
234 | { |
235 | struct poll_table_entry *entry; | |
236 | ||
237 | entry = container_of(wait, struct poll_table_entry, wait); | |
3ad6f93e | 238 | if (key && !(key_to_poll(key) & entry->key)) |
4938d7e0 ED |
239 | return 0; |
240 | return __pollwake(wait, mode, sync, key); | |
241 | } | |
242 | ||
70674f95 AK |
243 | /* Add a new entry */ |
244 | static void __pollwait(struct file *filp, wait_queue_head_t *wait_address, | |
245 | poll_table *p) | |
246 | { | |
5f820f64 TH |
247 | struct poll_wqueues *pwq = container_of(p, struct poll_wqueues, pt); |
248 | struct poll_table_entry *entry = poll_get_entry(pwq); | |
70674f95 AK |
249 | if (!entry) |
250 | return; | |
cb0942b8 | 251 | entry->filp = get_file(filp); |
70674f95 | 252 | entry->wait_address = wait_address; |
626cf236 | 253 | entry->key = p->_key; |
5f820f64 TH |
254 | init_waitqueue_func_entry(&entry->wait, pollwake); |
255 | entry->wait.private = pwq; | |
ccf6780d | 256 | add_wait_queue(wait_address, &entry->wait); |
1da177e4 LT |
257 | } |
258 | ||
8f546ae1 | 259 | static int poll_schedule_timeout(struct poll_wqueues *pwq, int state, |
5f820f64 TH |
260 | ktime_t *expires, unsigned long slack) |
261 | { | |
262 | int rc = -EINTR; | |
263 | ||
264 | set_current_state(state); | |
265 | if (!pwq->triggered) | |
59612d18 | 266 | rc = schedule_hrtimeout_range(expires, slack, HRTIMER_MODE_ABS); |
5f820f64 TH |
267 | __set_current_state(TASK_RUNNING); |
268 | ||
269 | /* | |
270 | * Prepare for the next iteration. | |
271 | * | |
b92b8b35 | 272 | * The following smp_store_mb() serves two purposes. First, it's |
5f820f64 TH |
273 | * the counterpart rmb of the wmb in pollwake() such that data |
274 | * written before wake up is always visible after wake up. | |
275 | * Second, the full barrier guarantees that triggered clearing | |
276 | * doesn't pass event check of the next iteration. Note that | |
277 | * this problem doesn't exist for the first iteration as | |
278 | * add_wait_queue() has full barrier semantics. | |
279 | */ | |
b92b8b35 | 280 | smp_store_mb(pwq->triggered, 0); |
5f820f64 TH |
281 | |
282 | return rc; | |
283 | } | |
5f820f64 | 284 | |
b773ad40 TG |
285 | /** |
286 | * poll_select_set_timeout - helper function to setup the timeout value | |
766b9f92 | 287 | * @to: pointer to timespec64 variable for the final timeout |
b773ad40 TG |
288 | * @sec: seconds (from user space) |
289 | * @nsec: nanoseconds (from user space) | |
290 | * | |
291 | * Note, we do not use a timespec for the user space value here, That | |
292 | * way we can use the function for timeval and compat interfaces as well. | |
293 | * | |
294 | * Returns -EINVAL if sec/nsec are not normalized. Otherwise 0. | |
295 | */ | |
766b9f92 | 296 | int poll_select_set_timeout(struct timespec64 *to, time64_t sec, long nsec) |
b773ad40 | 297 | { |
766b9f92 | 298 | struct timespec64 ts = {.tv_sec = sec, .tv_nsec = nsec}; |
b773ad40 | 299 | |
766b9f92 | 300 | if (!timespec64_valid(&ts)) |
b773ad40 TG |
301 | return -EINVAL; |
302 | ||
303 | /* Optimize for the zero timeout value here */ | |
304 | if (!sec && !nsec) { | |
305 | to->tv_sec = to->tv_nsec = 0; | |
306 | } else { | |
766b9f92 DD |
307 | ktime_get_ts64(to); |
308 | *to = timespec64_add_safe(*to, ts); | |
b773ad40 TG |
309 | } |
310 | return 0; | |
311 | } | |
312 | ||
766b9f92 DD |
313 | static int poll_select_copy_remaining(struct timespec64 *end_time, |
314 | void __user *p, | |
b773ad40 TG |
315 | int timeval, int ret) |
316 | { | |
36819ad0 | 317 | struct timespec64 rts; |
b773ad40 TG |
318 | struct timeval rtv; |
319 | ||
320 | if (!p) | |
321 | return ret; | |
322 | ||
323 | if (current->personality & STICKY_TIMEOUTS) | |
324 | goto sticky; | |
325 | ||
326 | /* No update for zero timeout */ | |
327 | if (!end_time->tv_sec && !end_time->tv_nsec) | |
328 | return ret; | |
329 | ||
36819ad0 DD |
330 | ktime_get_ts64(&rts); |
331 | rts = timespec64_sub(*end_time, rts); | |
332 | if (rts.tv_sec < 0) | |
333 | rts.tv_sec = rts.tv_nsec = 0; | |
766b9f92 | 334 | |
b773ad40 TG |
335 | |
336 | if (timeval) { | |
65329bf4 VK |
337 | if (sizeof(rtv) > sizeof(rtv.tv_sec) + sizeof(rtv.tv_usec)) |
338 | memset(&rtv, 0, sizeof(rtv)); | |
36819ad0 DD |
339 | rtv.tv_sec = rts.tv_sec; |
340 | rtv.tv_usec = rts.tv_nsec / NSEC_PER_USEC; | |
b773ad40 TG |
341 | |
342 | if (!copy_to_user(p, &rtv, sizeof(rtv))) | |
343 | return ret; | |
344 | ||
36819ad0 | 345 | } else if (!put_timespec64(&rts, p)) |
b773ad40 TG |
346 | return ret; |
347 | ||
348 | /* | |
349 | * If an application puts its timeval in read-only memory, we | |
350 | * don't want the Linux-specific update to the timeval to | |
351 | * cause a fault after the select has completed | |
352 | * successfully. However, because we're not updating the | |
353 | * timeval, we can't restart the system call. | |
354 | */ | |
355 | ||
356 | sticky: | |
357 | if (ret == -ERESTARTNOHAND) | |
358 | ret = -EINTR; | |
359 | return ret; | |
360 | } | |
361 | ||
e99ca56c AV |
362 | /* |
363 | * Scalable version of the fd_set. | |
364 | */ | |
365 | ||
366 | typedef struct { | |
367 | unsigned long *in, *out, *ex; | |
368 | unsigned long *res_in, *res_out, *res_ex; | |
369 | } fd_set_bits; | |
370 | ||
371 | /* | |
372 | * How many longwords for "nr" bits? | |
373 | */ | |
374 | #define FDS_BITPERLONG (8*sizeof(long)) | |
375 | #define FDS_LONGS(nr) (((nr)+FDS_BITPERLONG-1)/FDS_BITPERLONG) | |
376 | #define FDS_BYTES(nr) (FDS_LONGS(nr)*sizeof(long)) | |
377 | ||
378 | /* | |
379 | * We do a VERIFY_WRITE here even though we are only reading this time: | |
380 | * we'll write to it eventually.. | |
381 | * | |
382 | * Use "unsigned long" accesses to let user-mode fd_set's be long-aligned. | |
383 | */ | |
384 | static inline | |
385 | int get_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset) | |
386 | { | |
387 | nr = FDS_BYTES(nr); | |
388 | if (ufdset) | |
389 | return copy_from_user(fdset, ufdset, nr) ? -EFAULT : 0; | |
390 | ||
391 | memset(fdset, 0, nr); | |
392 | return 0; | |
393 | } | |
394 | ||
395 | static inline unsigned long __must_check | |
396 | set_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset) | |
397 | { | |
398 | if (ufdset) | |
399 | return __copy_to_user(ufdset, fdset, FDS_BYTES(nr)); | |
400 | return 0; | |
401 | } | |
402 | ||
403 | static inline | |
404 | void zero_fd_set(unsigned long nr, unsigned long *fdset) | |
405 | { | |
406 | memset(fdset, 0, FDS_BYTES(nr)); | |
407 | } | |
408 | ||
1da177e4 LT |
409 | #define FDS_IN(fds, n) (fds->in + n) |
410 | #define FDS_OUT(fds, n) (fds->out + n) | |
411 | #define FDS_EX(fds, n) (fds->ex + n) | |
412 | ||
413 | #define BITS(fds, n) (*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n)) | |
414 | ||
415 | static int max_select_fd(unsigned long n, fd_set_bits *fds) | |
416 | { | |
417 | unsigned long *open_fds; | |
418 | unsigned long set; | |
419 | int max; | |
badf1662 | 420 | struct fdtable *fdt; |
1da177e4 LT |
421 | |
422 | /* handle last in-complete long-word first */ | |
8ded2bbc JB |
423 | set = ~(~0UL << (n & (BITS_PER_LONG-1))); |
424 | n /= BITS_PER_LONG; | |
badf1662 | 425 | fdt = files_fdtable(current->files); |
1fd36adc | 426 | open_fds = fdt->open_fds + n; |
1da177e4 LT |
427 | max = 0; |
428 | if (set) { | |
429 | set &= BITS(fds, n); | |
430 | if (set) { | |
431 | if (!(set & ~*open_fds)) | |
432 | goto get_max; | |
433 | return -EBADF; | |
434 | } | |
435 | } | |
436 | while (n) { | |
437 | open_fds--; | |
438 | n--; | |
439 | set = BITS(fds, n); | |
440 | if (!set) | |
441 | continue; | |
442 | if (set & ~*open_fds) | |
443 | return -EBADF; | |
444 | if (max) | |
445 | continue; | |
446 | get_max: | |
447 | do { | |
448 | max++; | |
449 | set >>= 1; | |
450 | } while (set); | |
8ded2bbc | 451 | max += n * BITS_PER_LONG; |
1da177e4 LT |
452 | } |
453 | ||
454 | return max; | |
455 | } | |
456 | ||
a9a08845 LT |
457 | #define POLLIN_SET (EPOLLRDNORM | EPOLLRDBAND | EPOLLIN | EPOLLHUP | EPOLLERR) |
458 | #define POLLOUT_SET (EPOLLWRBAND | EPOLLWRNORM | EPOLLOUT | EPOLLERR) | |
459 | #define POLLEX_SET (EPOLLPRI) | |
1da177e4 | 460 | |
4938d7e0 | 461 | static inline void wait_key_set(poll_table *wait, unsigned long in, |
2d48d67f | 462 | unsigned long out, unsigned long bit, |
01699437 | 463 | __poll_t ll_flag) |
4938d7e0 | 464 | { |
2d48d67f | 465 | wait->_key = POLLEX_SET | ll_flag; |
626cf236 HV |
466 | if (in & bit) |
467 | wait->_key |= POLLIN_SET; | |
468 | if (out & bit) | |
469 | wait->_key |= POLLOUT_SET; | |
4938d7e0 ED |
470 | } |
471 | ||
e99ca56c | 472 | static int do_select(int n, fd_set_bits *fds, struct timespec64 *end_time) |
1da177e4 | 473 | { |
8ff3e8e8 | 474 | ktime_t expire, *to = NULL; |
1da177e4 LT |
475 | struct poll_wqueues table; |
476 | poll_table *wait; | |
8ff3e8e8 | 477 | int retval, i, timed_out = 0; |
da8b44d5 | 478 | u64 slack = 0; |
01699437 | 479 | __poll_t busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0; |
37056719 | 480 | unsigned long busy_start = 0; |
1da177e4 | 481 | |
b835996f | 482 | rcu_read_lock(); |
1da177e4 | 483 | retval = max_select_fd(n, fds); |
b835996f | 484 | rcu_read_unlock(); |
1da177e4 LT |
485 | |
486 | if (retval < 0) | |
487 | return retval; | |
488 | n = retval; | |
489 | ||
490 | poll_initwait(&table); | |
491 | wait = &table.pt; | |
8ff3e8e8 | 492 | if (end_time && !end_time->tv_sec && !end_time->tv_nsec) { |
626cf236 | 493 | wait->_qproc = NULL; |
8ff3e8e8 AV |
494 | timed_out = 1; |
495 | } | |
496 | ||
96d2ab48 | 497 | if (end_time && !timed_out) |
231f3d39 | 498 | slack = select_estimate_accuracy(end_time); |
90d6e24a | 499 | |
1da177e4 LT |
500 | retval = 0; |
501 | for (;;) { | |
502 | unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp; | |
cbf55001 | 503 | bool can_busy_loop = false; |
1da177e4 | 504 | |
1da177e4 LT |
505 | inp = fds->in; outp = fds->out; exp = fds->ex; |
506 | rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex; | |
507 | ||
508 | for (i = 0; i < n; ++rinp, ++routp, ++rexp) { | |
e6c8adca | 509 | unsigned long in, out, ex, all_bits, bit = 1, j; |
1da177e4 | 510 | unsigned long res_in = 0, res_out = 0, res_ex = 0; |
e6c8adca | 511 | __poll_t mask; |
1da177e4 LT |
512 | |
513 | in = *inp++; out = *outp++; ex = *exp++; | |
514 | all_bits = in | out | ex; | |
515 | if (all_bits == 0) { | |
8ded2bbc | 516 | i += BITS_PER_LONG; |
1da177e4 LT |
517 | continue; |
518 | } | |
519 | ||
8ded2bbc | 520 | for (j = 0; j < BITS_PER_LONG; ++j, ++i, bit <<= 1) { |
2903ff01 | 521 | struct fd f; |
1da177e4 LT |
522 | if (i >= n) |
523 | break; | |
524 | if (!(bit & all_bits)) | |
525 | continue; | |
2903ff01 AV |
526 | f = fdget(i); |
527 | if (f.file) { | |
9965ed17 CH |
528 | wait_key_set(wait, in, out, bit, |
529 | busy_flag); | |
530 | mask = vfs_poll(f.file, wait); | |
531 | ||
2903ff01 | 532 | fdput(f); |
1da177e4 LT |
533 | if ((mask & POLLIN_SET) && (in & bit)) { |
534 | res_in |= bit; | |
535 | retval++; | |
626cf236 | 536 | wait->_qproc = NULL; |
1da177e4 LT |
537 | } |
538 | if ((mask & POLLOUT_SET) && (out & bit)) { | |
539 | res_out |= bit; | |
540 | retval++; | |
626cf236 | 541 | wait->_qproc = NULL; |
1da177e4 LT |
542 | } |
543 | if ((mask & POLLEX_SET) && (ex & bit)) { | |
544 | res_ex |= bit; | |
545 | retval++; | |
626cf236 | 546 | wait->_qproc = NULL; |
1da177e4 | 547 | } |
2d48d67f | 548 | /* got something, stop busy polling */ |
cbf55001 ET |
549 | if (retval) { |
550 | can_busy_loop = false; | |
551 | busy_flag = 0; | |
552 | ||
553 | /* | |
554 | * only remember a returned | |
555 | * POLL_BUSY_LOOP if we asked for it | |
556 | */ | |
557 | } else if (busy_flag & mask) | |
558 | can_busy_loop = true; | |
559 | ||
1da177e4 | 560 | } |
1da177e4 LT |
561 | } |
562 | if (res_in) | |
563 | *rinp = res_in; | |
564 | if (res_out) | |
565 | *routp = res_out; | |
566 | if (res_ex) | |
567 | *rexp = res_ex; | |
55d85384 | 568 | cond_resched(); |
1da177e4 | 569 | } |
626cf236 | 570 | wait->_qproc = NULL; |
8ff3e8e8 | 571 | if (retval || timed_out || signal_pending(current)) |
1da177e4 | 572 | break; |
f5264481 | 573 | if (table.error) { |
1da177e4 LT |
574 | retval = table.error; |
575 | break; | |
576 | } | |
9f72949f | 577 | |
cbf55001 | 578 | /* only if found POLL_BUSY_LOOP sockets && not out of time */ |
76b1e9b9 | 579 | if (can_busy_loop && !need_resched()) { |
37056719 AD |
580 | if (!busy_start) { |
581 | busy_start = busy_loop_current_time(); | |
76b1e9b9 ET |
582 | continue; |
583 | } | |
37056719 | 584 | if (!busy_loop_timeout(busy_start)) |
76b1e9b9 ET |
585 | continue; |
586 | } | |
587 | busy_flag = 0; | |
2d48d67f | 588 | |
8ff3e8e8 AV |
589 | /* |
590 | * If this is the first loop and we have a timeout | |
591 | * given, then we convert to ktime_t and set the to | |
592 | * pointer to the expiry value. | |
593 | */ | |
594 | if (end_time && !to) { | |
766b9f92 | 595 | expire = timespec64_to_ktime(*end_time); |
8ff3e8e8 | 596 | to = &expire; |
9f72949f | 597 | } |
8ff3e8e8 | 598 | |
5f820f64 TH |
599 | if (!poll_schedule_timeout(&table, TASK_INTERRUPTIBLE, |
600 | to, slack)) | |
8ff3e8e8 | 601 | timed_out = 1; |
1da177e4 | 602 | } |
1da177e4 LT |
603 | |
604 | poll_freewait(&table); | |
605 | ||
1da177e4 LT |
606 | return retval; |
607 | } | |
608 | ||
1da177e4 LT |
609 | /* |
610 | * We can actually return ERESTARTSYS instead of EINTR, but I'd | |
611 | * like to be certain this leads to no problems. So I return | |
612 | * EINTR just for safety. | |
613 | * | |
614 | * Update: ERESTARTSYS breaks at least the xview clock binary, so | |
615 | * I'm trying ERESTARTNOHAND which restart only when you want to. | |
616 | */ | |
a2dcb44c | 617 | int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp, |
766b9f92 | 618 | fd_set __user *exp, struct timespec64 *end_time) |
1da177e4 LT |
619 | { |
620 | fd_set_bits fds; | |
29ff2db5 | 621 | void *bits; |
bbea9f69 | 622 | int ret, max_fds; |
2d19309c | 623 | size_t size, alloc_size; |
badf1662 | 624 | struct fdtable *fdt; |
70674f95 | 625 | /* Allocate small arguments on the stack to save memory and be faster */ |
30c14e40 | 626 | long stack_fds[SELECT_STACK_ALLOC/sizeof(long)]; |
1da177e4 | 627 | |
1da177e4 LT |
628 | ret = -EINVAL; |
629 | if (n < 0) | |
630 | goto out_nofds; | |
631 | ||
bbea9f69 | 632 | /* max_fds can increase, so grab it once to avoid race */ |
b835996f | 633 | rcu_read_lock(); |
badf1662 | 634 | fdt = files_fdtable(current->files); |
bbea9f69 | 635 | max_fds = fdt->max_fds; |
b835996f | 636 | rcu_read_unlock(); |
bbea9f69 VL |
637 | if (n > max_fds) |
638 | n = max_fds; | |
1da177e4 LT |
639 | |
640 | /* | |
641 | * We need 6 bitmaps (in/out/ex for both incoming and outgoing), | |
642 | * since we used fdset we need to allocate memory in units of | |
643 | * long-words. | |
644 | */ | |
1da177e4 | 645 | size = FDS_BYTES(n); |
b04eb6aa MBJ |
646 | bits = stack_fds; |
647 | if (size > sizeof(stack_fds) / 6) { | |
648 | /* Not enough space in on-stack array; must use kmalloc */ | |
649 | ret = -ENOMEM; | |
2d19309c VB |
650 | if (size > (SIZE_MAX / 6)) |
651 | goto out_nofds; | |
652 | ||
653 | alloc_size = 6 * size; | |
752ade68 | 654 | bits = kvmalloc(alloc_size, GFP_KERNEL); |
b04eb6aa MBJ |
655 | if (!bits) |
656 | goto out_nofds; | |
657 | } | |
29ff2db5 AM |
658 | fds.in = bits; |
659 | fds.out = bits + size; | |
660 | fds.ex = bits + 2*size; | |
661 | fds.res_in = bits + 3*size; | |
662 | fds.res_out = bits + 4*size; | |
663 | fds.res_ex = bits + 5*size; | |
1da177e4 LT |
664 | |
665 | if ((ret = get_fd_set(n, inp, fds.in)) || | |
666 | (ret = get_fd_set(n, outp, fds.out)) || | |
667 | (ret = get_fd_set(n, exp, fds.ex))) | |
668 | goto out; | |
669 | zero_fd_set(n, fds.res_in); | |
670 | zero_fd_set(n, fds.res_out); | |
671 | zero_fd_set(n, fds.res_ex); | |
672 | ||
8ff3e8e8 | 673 | ret = do_select(n, &fds, end_time); |
1da177e4 LT |
674 | |
675 | if (ret < 0) | |
676 | goto out; | |
677 | if (!ret) { | |
678 | ret = -ERESTARTNOHAND; | |
679 | if (signal_pending(current)) | |
680 | goto out; | |
681 | ret = 0; | |
682 | } | |
683 | ||
684 | if (set_fd_set(n, inp, fds.res_in) || | |
685 | set_fd_set(n, outp, fds.res_out) || | |
686 | set_fd_set(n, exp, fds.res_ex)) | |
687 | ret = -EFAULT; | |
688 | ||
689 | out: | |
70674f95 | 690 | if (bits != stack_fds) |
2d19309c | 691 | kvfree(bits); |
1da177e4 LT |
692 | out_nofds: |
693 | return ret; | |
694 | } | |
695 | ||
4bdb9aca DB |
696 | static int kern_select(int n, fd_set __user *inp, fd_set __user *outp, |
697 | fd_set __user *exp, struct timeval __user *tvp) | |
9f72949f | 698 | { |
766b9f92 | 699 | struct timespec64 end_time, *to = NULL; |
9f72949f DW |
700 | struct timeval tv; |
701 | int ret; | |
702 | ||
703 | if (tvp) { | |
704 | if (copy_from_user(&tv, tvp, sizeof(tv))) | |
705 | return -EFAULT; | |
706 | ||
8ff3e8e8 | 707 | to = &end_time; |
4d36a9e6 AV |
708 | if (poll_select_set_timeout(to, |
709 | tv.tv_sec + (tv.tv_usec / USEC_PER_SEC), | |
710 | (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC)) | |
9f72949f | 711 | return -EINVAL; |
9f72949f DW |
712 | } |
713 | ||
8ff3e8e8 AV |
714 | ret = core_sys_select(n, inp, outp, exp, to); |
715 | ret = poll_select_copy_remaining(&end_time, tvp, 1, ret); | |
9f72949f DW |
716 | |
717 | return ret; | |
718 | } | |
719 | ||
4bdb9aca DB |
720 | SYSCALL_DEFINE5(select, int, n, fd_set __user *, inp, fd_set __user *, outp, |
721 | fd_set __user *, exp, struct timeval __user *, tvp) | |
722 | { | |
723 | return kern_select(n, inp, outp, exp, tvp); | |
724 | } | |
725 | ||
c9da9f21 HC |
726 | static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp, |
727 | fd_set __user *exp, struct timespec __user *tsp, | |
728 | const sigset_t __user *sigmask, size_t sigsetsize) | |
9f72949f | 729 | { |
9f72949f | 730 | sigset_t ksigmask, sigsaved; |
36819ad0 | 731 | struct timespec64 ts, end_time, *to = NULL; |
9f72949f DW |
732 | int ret; |
733 | ||
734 | if (tsp) { | |
36819ad0 | 735 | if (get_timespec64(&ts, tsp)) |
9f72949f DW |
736 | return -EFAULT; |
737 | ||
8ff3e8e8 | 738 | to = &end_time; |
36819ad0 | 739 | if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) |
9f72949f | 740 | return -EINVAL; |
9f72949f DW |
741 | } |
742 | ||
743 | if (sigmask) { | |
744 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
745 | if (sigsetsize != sizeof(sigset_t)) | |
746 | return -EINVAL; | |
747 | if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask))) | |
748 | return -EFAULT; | |
749 | ||
750 | sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
751 | sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); | |
752 | } | |
753 | ||
62568510 | 754 | ret = core_sys_select(n, inp, outp, exp, to); |
8ff3e8e8 | 755 | ret = poll_select_copy_remaining(&end_time, tsp, 0, ret); |
9f72949f DW |
756 | |
757 | if (ret == -ERESTARTNOHAND) { | |
758 | /* | |
759 | * Don't restore the signal mask yet. Let do_signal() deliver | |
760 | * the signal on the way back to userspace, before the signal | |
761 | * mask is restored. | |
762 | */ | |
763 | if (sigmask) { | |
764 | memcpy(¤t->saved_sigmask, &sigsaved, | |
765 | sizeof(sigsaved)); | |
4e4c22c7 | 766 | set_restore_sigmask(); |
9f72949f DW |
767 | } |
768 | } else if (sigmask) | |
769 | sigprocmask(SIG_SETMASK, &sigsaved, NULL); | |
770 | ||
771 | return ret; | |
772 | } | |
773 | ||
774 | /* | |
775 | * Most architectures can't handle 7-argument syscalls. So we provide a | |
776 | * 6-argument version where the sixth argument is a pointer to a structure | |
777 | * which has a pointer to the sigset_t itself followed by a size_t containing | |
778 | * the sigset size. | |
779 | */ | |
d4e82042 HC |
780 | SYSCALL_DEFINE6(pselect6, int, n, fd_set __user *, inp, fd_set __user *, outp, |
781 | fd_set __user *, exp, struct timespec __user *, tsp, | |
782 | void __user *, sig) | |
9f72949f DW |
783 | { |
784 | size_t sigsetsize = 0; | |
785 | sigset_t __user *up = NULL; | |
786 | ||
787 | if (sig) { | |
788 | if (!access_ok(VERIFY_READ, sig, sizeof(void *)+sizeof(size_t)) | |
e110ab94 | 789 | || __get_user(up, (sigset_t __user * __user *)sig) |
9f72949f | 790 | || __get_user(sigsetsize, |
e110ab94 | 791 | (size_t __user *)(sig+sizeof(void *)))) |
9f72949f DW |
792 | return -EFAULT; |
793 | } | |
794 | ||
c9da9f21 | 795 | return do_pselect(n, inp, outp, exp, tsp, up, sigsetsize); |
9f72949f | 796 | } |
9f72949f | 797 | |
5d0e5283 CH |
798 | #ifdef __ARCH_WANT_SYS_OLD_SELECT |
799 | struct sel_arg_struct { | |
800 | unsigned long n; | |
801 | fd_set __user *inp, *outp, *exp; | |
802 | struct timeval __user *tvp; | |
803 | }; | |
804 | ||
805 | SYSCALL_DEFINE1(old_select, struct sel_arg_struct __user *, arg) | |
806 | { | |
807 | struct sel_arg_struct a; | |
808 | ||
809 | if (copy_from_user(&a, arg, sizeof(a))) | |
810 | return -EFAULT; | |
4bdb9aca | 811 | return kern_select(a.n, a.inp, a.outp, a.exp, a.tvp); |
5d0e5283 CH |
812 | } |
813 | #endif | |
814 | ||
1da177e4 LT |
815 | struct poll_list { |
816 | struct poll_list *next; | |
817 | int len; | |
818 | struct pollfd entries[0]; | |
819 | }; | |
820 | ||
821 | #define POLLFD_PER_PAGE ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd)) | |
822 | ||
4a4b69f7 VL |
823 | /* |
824 | * Fish for pollable events on the pollfd->fd file descriptor. We're only | |
825 | * interested in events matching the pollfd->events mask, and the result | |
826 | * matching that mask is both recorded in pollfd->revents and returned. The | |
827 | * pwait poll_table will be used by the fd-provided poll handler for waiting, | |
626cf236 | 828 | * if pwait->_qproc is non-NULL. |
4a4b69f7 | 829 | */ |
fb367937 | 830 | static inline __poll_t do_pollfd(struct pollfd *pollfd, poll_table *pwait, |
cbf55001 | 831 | bool *can_busy_poll, |
fb367937 | 832 | __poll_t busy_flag) |
1da177e4 | 833 | { |
a0f8dcfc CH |
834 | int fd = pollfd->fd; |
835 | __poll_t mask = 0, filter; | |
836 | struct fd f; | |
837 | ||
838 | if (fd < 0) | |
839 | goto out; | |
840 | mask = EPOLLNVAL; | |
841 | f = fdget(fd); | |
842 | if (!f.file) | |
843 | goto out; | |
844 | ||
845 | /* userland u16 ->events contains POLL... bitmap */ | |
846 | filter = demangle_poll(pollfd->events) | EPOLLERR | EPOLLHUP; | |
9965ed17 CH |
847 | pwait->_key = filter | busy_flag; |
848 | mask = vfs_poll(f.file, pwait); | |
849 | if (mask & busy_flag) | |
850 | *can_busy_poll = true; | |
a0f8dcfc CH |
851 | mask &= filter; /* Mask out unneeded events. */ |
852 | fdput(f); | |
853 | ||
854 | out: | |
fb367937 | 855 | /* ... and so does ->revents */ |
c71d227f | 856 | pollfd->revents = mangle_poll(mask); |
4a4b69f7 | 857 | return mask; |
1da177e4 LT |
858 | } |
859 | ||
ccec5ee3 | 860 | static int do_poll(struct poll_list *list, struct poll_wqueues *wait, |
766b9f92 | 861 | struct timespec64 *end_time) |
1da177e4 | 862 | { |
1da177e4 | 863 | poll_table* pt = &wait->pt; |
8ff3e8e8 AV |
864 | ktime_t expire, *to = NULL; |
865 | int timed_out = 0, count = 0; | |
da8b44d5 | 866 | u64 slack = 0; |
fb367937 | 867 | __poll_t busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0; |
37056719 | 868 | unsigned long busy_start = 0; |
1da177e4 | 869 | |
9f72949f | 870 | /* Optimise the no-wait case */ |
8ff3e8e8 | 871 | if (end_time && !end_time->tv_sec && !end_time->tv_nsec) { |
626cf236 | 872 | pt->_qproc = NULL; |
8ff3e8e8 AV |
873 | timed_out = 1; |
874 | } | |
9bf084f7 | 875 | |
96d2ab48 | 876 | if (end_time && !timed_out) |
231f3d39 | 877 | slack = select_estimate_accuracy(end_time); |
90d6e24a | 878 | |
1da177e4 LT |
879 | for (;;) { |
880 | struct poll_list *walk; | |
cbf55001 | 881 | bool can_busy_loop = false; |
9f72949f | 882 | |
4a4b69f7 VL |
883 | for (walk = list; walk != NULL; walk = walk->next) { |
884 | struct pollfd * pfd, * pfd_end; | |
885 | ||
886 | pfd = walk->entries; | |
887 | pfd_end = pfd + walk->len; | |
888 | for (; pfd != pfd_end; pfd++) { | |
889 | /* | |
890 | * Fish for events. If we found one, record it | |
626cf236 | 891 | * and kill poll_table->_qproc, so we don't |
4a4b69f7 VL |
892 | * needlessly register any other waiters after |
893 | * this. They'll get immediately deregistered | |
894 | * when we break out and return. | |
895 | */ | |
cbf55001 ET |
896 | if (do_pollfd(pfd, pt, &can_busy_loop, |
897 | busy_flag)) { | |
4a4b69f7 | 898 | count++; |
626cf236 | 899 | pt->_qproc = NULL; |
cbf55001 ET |
900 | /* found something, stop busy polling */ |
901 | busy_flag = 0; | |
902 | can_busy_loop = false; | |
4a4b69f7 VL |
903 | } |
904 | } | |
1da177e4 | 905 | } |
4a4b69f7 VL |
906 | /* |
907 | * All waiters have already been registered, so don't provide | |
626cf236 | 908 | * a poll_table->_qproc to them on the next loop iteration. |
4a4b69f7 | 909 | */ |
626cf236 | 910 | pt->_qproc = NULL; |
9bf084f7 ON |
911 | if (!count) { |
912 | count = wait->error; | |
913 | if (signal_pending(current)) | |
914 | count = -EINTR; | |
915 | } | |
8ff3e8e8 | 916 | if (count || timed_out) |
1da177e4 | 917 | break; |
9f72949f | 918 | |
cbf55001 | 919 | /* only if found POLL_BUSY_LOOP sockets && not out of time */ |
76b1e9b9 | 920 | if (can_busy_loop && !need_resched()) { |
37056719 AD |
921 | if (!busy_start) { |
922 | busy_start = busy_loop_current_time(); | |
76b1e9b9 ET |
923 | continue; |
924 | } | |
37056719 | 925 | if (!busy_loop_timeout(busy_start)) |
76b1e9b9 ET |
926 | continue; |
927 | } | |
928 | busy_flag = 0; | |
91e2fd33 | 929 | |
8ff3e8e8 AV |
930 | /* |
931 | * If this is the first loop and we have a timeout | |
932 | * given, then we convert to ktime_t and set the to | |
933 | * pointer to the expiry value. | |
934 | */ | |
935 | if (end_time && !to) { | |
766b9f92 | 936 | expire = timespec64_to_ktime(*end_time); |
8ff3e8e8 | 937 | to = &expire; |
9f72949f DW |
938 | } |
939 | ||
5f820f64 | 940 | if (!poll_schedule_timeout(wait, TASK_INTERRUPTIBLE, to, slack)) |
8ff3e8e8 | 941 | timed_out = 1; |
1da177e4 | 942 | } |
1da177e4 LT |
943 | return count; |
944 | } | |
945 | ||
70674f95 AK |
946 | #define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \ |
947 | sizeof(struct pollfd)) | |
948 | ||
e99ca56c | 949 | static int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds, |
766b9f92 | 950 | struct timespec64 *end_time) |
1da177e4 LT |
951 | { |
952 | struct poll_wqueues table; | |
252e5725 | 953 | int err = -EFAULT, fdcount, len, size; |
30c14e40 JS |
954 | /* Allocate small arguments on the stack to save memory and be |
955 | faster - use long to make sure the buffer is aligned properly | |
956 | on 64 bit archs to avoid unaligned access */ | |
957 | long stack_pps[POLL_STACK_ALLOC/sizeof(long)]; | |
252e5725 ON |
958 | struct poll_list *const head = (struct poll_list *)stack_pps; |
959 | struct poll_list *walk = head; | |
960 | unsigned long todo = nfds; | |
1da177e4 | 961 | |
d554ed89 | 962 | if (nfds > rlimit(RLIMIT_NOFILE)) |
1da177e4 LT |
963 | return -EINVAL; |
964 | ||
252e5725 ON |
965 | len = min_t(unsigned int, nfds, N_STACK_PPS); |
966 | for (;;) { | |
967 | walk->next = NULL; | |
968 | walk->len = len; | |
969 | if (!len) | |
970 | break; | |
1da177e4 | 971 | |
252e5725 ON |
972 | if (copy_from_user(walk->entries, ufds + nfds-todo, |
973 | sizeof(struct pollfd) * walk->len)) | |
974 | goto out_fds; | |
975 | ||
976 | todo -= walk->len; | |
977 | if (!todo) | |
978 | break; | |
1da177e4 | 979 | |
252e5725 ON |
980 | len = min(todo, POLLFD_PER_PAGE); |
981 | size = sizeof(struct poll_list) + sizeof(struct pollfd) * len; | |
982 | walk = walk->next = kmalloc(size, GFP_KERNEL); | |
983 | if (!walk) { | |
984 | err = -ENOMEM; | |
1da177e4 LT |
985 | goto out_fds; |
986 | } | |
1da177e4 | 987 | } |
9f72949f | 988 | |
252e5725 | 989 | poll_initwait(&table); |
ccec5ee3 | 990 | fdcount = do_poll(head, &table, end_time); |
252e5725 | 991 | poll_freewait(&table); |
1da177e4 | 992 | |
252e5725 | 993 | for (walk = head; walk; walk = walk->next) { |
1da177e4 LT |
994 | struct pollfd *fds = walk->entries; |
995 | int j; | |
996 | ||
252e5725 ON |
997 | for (j = 0; j < walk->len; j++, ufds++) |
998 | if (__put_user(fds[j].revents, &ufds->revents)) | |
1da177e4 | 999 | goto out_fds; |
1da177e4 | 1000 | } |
252e5725 | 1001 | |
1da177e4 | 1002 | err = fdcount; |
1da177e4 | 1003 | out_fds: |
252e5725 ON |
1004 | walk = head->next; |
1005 | while (walk) { | |
1006 | struct poll_list *pos = walk; | |
1007 | walk = walk->next; | |
1008 | kfree(pos); | |
1da177e4 | 1009 | } |
252e5725 | 1010 | |
1da177e4 LT |
1011 | return err; |
1012 | } | |
9f72949f | 1013 | |
3075d9da CW |
1014 | static long do_restart_poll(struct restart_block *restart_block) |
1015 | { | |
8ff3e8e8 AV |
1016 | struct pollfd __user *ufds = restart_block->poll.ufds; |
1017 | int nfds = restart_block->poll.nfds; | |
766b9f92 | 1018 | struct timespec64 *to = NULL, end_time; |
3075d9da CW |
1019 | int ret; |
1020 | ||
8ff3e8e8 AV |
1021 | if (restart_block->poll.has_timeout) { |
1022 | end_time.tv_sec = restart_block->poll.tv_sec; | |
1023 | end_time.tv_nsec = restart_block->poll.tv_nsec; | |
1024 | to = &end_time; | |
1025 | } | |
1026 | ||
1027 | ret = do_sys_poll(ufds, nfds, to); | |
1028 | ||
3075d9da CW |
1029 | if (ret == -EINTR) { |
1030 | restart_block->fn = do_restart_poll; | |
3075d9da CW |
1031 | ret = -ERESTART_RESTARTBLOCK; |
1032 | } | |
1033 | return ret; | |
1034 | } | |
1035 | ||
5a8a82b1 | 1036 | SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds, |
faf30900 | 1037 | int, timeout_msecs) |
9f72949f | 1038 | { |
766b9f92 | 1039 | struct timespec64 end_time, *to = NULL; |
3075d9da | 1040 | int ret; |
9f72949f | 1041 | |
8ff3e8e8 AV |
1042 | if (timeout_msecs >= 0) { |
1043 | to = &end_time; | |
1044 | poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC, | |
1045 | NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC)); | |
9f72949f DW |
1046 | } |
1047 | ||
8ff3e8e8 AV |
1048 | ret = do_sys_poll(ufds, nfds, to); |
1049 | ||
3075d9da CW |
1050 | if (ret == -EINTR) { |
1051 | struct restart_block *restart_block; | |
8ff3e8e8 | 1052 | |
f56141e3 | 1053 | restart_block = ¤t->restart_block; |
3075d9da | 1054 | restart_block->fn = do_restart_poll; |
8ff3e8e8 AV |
1055 | restart_block->poll.ufds = ufds; |
1056 | restart_block->poll.nfds = nfds; | |
1057 | ||
1058 | if (timeout_msecs >= 0) { | |
1059 | restart_block->poll.tv_sec = end_time.tv_sec; | |
1060 | restart_block->poll.tv_nsec = end_time.tv_nsec; | |
1061 | restart_block->poll.has_timeout = 1; | |
1062 | } else | |
1063 | restart_block->poll.has_timeout = 0; | |
1064 | ||
3075d9da CW |
1065 | ret = -ERESTART_RESTARTBLOCK; |
1066 | } | |
1067 | return ret; | |
9f72949f DW |
1068 | } |
1069 | ||
d4e82042 HC |
1070 | SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds, |
1071 | struct timespec __user *, tsp, const sigset_t __user *, sigmask, | |
1072 | size_t, sigsetsize) | |
9f72949f DW |
1073 | { |
1074 | sigset_t ksigmask, sigsaved; | |
36819ad0 | 1075 | struct timespec64 ts, end_time, *to = NULL; |
9f72949f DW |
1076 | int ret; |
1077 | ||
1078 | if (tsp) { | |
36819ad0 | 1079 | if (get_timespec64(&ts, tsp)) |
9f72949f DW |
1080 | return -EFAULT; |
1081 | ||
8ff3e8e8 AV |
1082 | to = &end_time; |
1083 | if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) | |
1084 | return -EINVAL; | |
9f72949f DW |
1085 | } |
1086 | ||
1087 | if (sigmask) { | |
1088 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
1089 | if (sigsetsize != sizeof(sigset_t)) | |
1090 | return -EINVAL; | |
1091 | if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask))) | |
1092 | return -EFAULT; | |
1093 | ||
1094 | sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
1095 | sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); | |
1096 | } | |
1097 | ||
8ff3e8e8 | 1098 | ret = do_sys_poll(ufds, nfds, to); |
9f72949f DW |
1099 | |
1100 | /* We can restart this syscall, usually */ | |
1101 | if (ret == -EINTR) { | |
1102 | /* | |
1103 | * Don't restore the signal mask yet. Let do_signal() deliver | |
1104 | * the signal on the way back to userspace, before the signal | |
1105 | * mask is restored. | |
1106 | */ | |
1107 | if (sigmask) { | |
1108 | memcpy(¤t->saved_sigmask, &sigsaved, | |
1109 | sizeof(sigsaved)); | |
4e4c22c7 | 1110 | set_restore_sigmask(); |
9f72949f DW |
1111 | } |
1112 | ret = -ERESTARTNOHAND; | |
1113 | } else if (sigmask) | |
1114 | sigprocmask(SIG_SETMASK, &sigsaved, NULL); | |
1115 | ||
8ff3e8e8 | 1116 | ret = poll_select_copy_remaining(&end_time, tsp, 0, ret); |
9f72949f DW |
1117 | |
1118 | return ret; | |
1119 | } | |
e99ca56c AV |
1120 | |
1121 | #ifdef CONFIG_COMPAT | |
1122 | #define __COMPAT_NFDBITS (8 * sizeof(compat_ulong_t)) | |
1123 | ||
1124 | static | |
36819ad0 | 1125 | int compat_poll_select_copy_remaining(struct timespec64 *end_time, void __user *p, |
e99ca56c AV |
1126 | int timeval, int ret) |
1127 | { | |
36819ad0 | 1128 | struct timespec64 ts; |
e99ca56c AV |
1129 | |
1130 | if (!p) | |
1131 | return ret; | |
1132 | ||
1133 | if (current->personality & STICKY_TIMEOUTS) | |
1134 | goto sticky; | |
1135 | ||
1136 | /* No update for zero timeout */ | |
1137 | if (!end_time->tv_sec && !end_time->tv_nsec) | |
1138 | return ret; | |
1139 | ||
36819ad0 DD |
1140 | ktime_get_ts64(&ts); |
1141 | ts = timespec64_sub(*end_time, ts); | |
e99ca56c AV |
1142 | if (ts.tv_sec < 0) |
1143 | ts.tv_sec = ts.tv_nsec = 0; | |
1144 | ||
1145 | if (timeval) { | |
1146 | struct compat_timeval rtv; | |
1147 | ||
1148 | rtv.tv_sec = ts.tv_sec; | |
1149 | rtv.tv_usec = ts.tv_nsec / NSEC_PER_USEC; | |
1150 | ||
1151 | if (!copy_to_user(p, &rtv, sizeof(rtv))) | |
1152 | return ret; | |
1153 | } else { | |
36819ad0 | 1154 | if (!compat_put_timespec64(&ts, p)) |
e99ca56c AV |
1155 | return ret; |
1156 | } | |
1157 | /* | |
1158 | * If an application puts its timeval in read-only memory, we | |
1159 | * don't want the Linux-specific update to the timeval to | |
1160 | * cause a fault after the select has completed | |
1161 | * successfully. However, because we're not updating the | |
1162 | * timeval, we can't restart the system call. | |
1163 | */ | |
1164 | ||
1165 | sticky: | |
1166 | if (ret == -ERESTARTNOHAND) | |
1167 | ret = -EINTR; | |
1168 | return ret; | |
1169 | } | |
1170 | ||
1171 | /* | |
1172 | * Ooo, nasty. We need here to frob 32-bit unsigned longs to | |
1173 | * 64-bit unsigned longs. | |
1174 | */ | |
1175 | static | |
1176 | int compat_get_fd_set(unsigned long nr, compat_ulong_t __user *ufdset, | |
1177 | unsigned long *fdset) | |
1178 | { | |
e99ca56c | 1179 | if (ufdset) { |
464d6242 | 1180 | return compat_get_bitmap(fdset, ufdset, nr); |
e99ca56c | 1181 | } else { |
79de3cbe | 1182 | zero_fd_set(nr, fdset); |
464d6242 | 1183 | return 0; |
e99ca56c | 1184 | } |
e99ca56c AV |
1185 | } |
1186 | ||
1187 | static | |
1188 | int compat_set_fd_set(unsigned long nr, compat_ulong_t __user *ufdset, | |
1189 | unsigned long *fdset) | |
1190 | { | |
e99ca56c AV |
1191 | if (!ufdset) |
1192 | return 0; | |
464d6242 | 1193 | return compat_put_bitmap(ufdset, fdset, nr); |
e99ca56c AV |
1194 | } |
1195 | ||
1196 | ||
1197 | /* | |
1198 | * This is a virtual copy of sys_select from fs/select.c and probably | |
1199 | * should be compared to it from time to time | |
1200 | */ | |
1201 | ||
1202 | /* | |
1203 | * We can actually return ERESTARTSYS instead of EINTR, but I'd | |
1204 | * like to be certain this leads to no problems. So I return | |
1205 | * EINTR just for safety. | |
1206 | * | |
1207 | * Update: ERESTARTSYS breaks at least the xview clock binary, so | |
1208 | * I'm trying ERESTARTNOHAND which restart only when you want to. | |
1209 | */ | |
1210 | static int compat_core_sys_select(int n, compat_ulong_t __user *inp, | |
1211 | compat_ulong_t __user *outp, compat_ulong_t __user *exp, | |
36819ad0 | 1212 | struct timespec64 *end_time) |
e99ca56c AV |
1213 | { |
1214 | fd_set_bits fds; | |
1215 | void *bits; | |
1216 | int size, max_fds, ret = -EINVAL; | |
1217 | struct fdtable *fdt; | |
1218 | long stack_fds[SELECT_STACK_ALLOC/sizeof(long)]; | |
1219 | ||
1220 | if (n < 0) | |
1221 | goto out_nofds; | |
1222 | ||
1223 | /* max_fds can increase, so grab it once to avoid race */ | |
1224 | rcu_read_lock(); | |
1225 | fdt = files_fdtable(current->files); | |
1226 | max_fds = fdt->max_fds; | |
1227 | rcu_read_unlock(); | |
1228 | if (n > max_fds) | |
1229 | n = max_fds; | |
1230 | ||
1231 | /* | |
1232 | * We need 6 bitmaps (in/out/ex for both incoming and outgoing), | |
1233 | * since we used fdset we need to allocate memory in units of | |
1234 | * long-words. | |
1235 | */ | |
1236 | size = FDS_BYTES(n); | |
1237 | bits = stack_fds; | |
1238 | if (size > sizeof(stack_fds) / 6) { | |
6da2ec56 | 1239 | bits = kmalloc_array(6, size, GFP_KERNEL); |
e99ca56c AV |
1240 | ret = -ENOMEM; |
1241 | if (!bits) | |
1242 | goto out_nofds; | |
1243 | } | |
1244 | fds.in = (unsigned long *) bits; | |
1245 | fds.out = (unsigned long *) (bits + size); | |
1246 | fds.ex = (unsigned long *) (bits + 2*size); | |
1247 | fds.res_in = (unsigned long *) (bits + 3*size); | |
1248 | fds.res_out = (unsigned long *) (bits + 4*size); | |
1249 | fds.res_ex = (unsigned long *) (bits + 5*size); | |
1250 | ||
1251 | if ((ret = compat_get_fd_set(n, inp, fds.in)) || | |
1252 | (ret = compat_get_fd_set(n, outp, fds.out)) || | |
1253 | (ret = compat_get_fd_set(n, exp, fds.ex))) | |
1254 | goto out; | |
1255 | zero_fd_set(n, fds.res_in); | |
1256 | zero_fd_set(n, fds.res_out); | |
1257 | zero_fd_set(n, fds.res_ex); | |
1258 | ||
1259 | ret = do_select(n, &fds, end_time); | |
1260 | ||
1261 | if (ret < 0) | |
1262 | goto out; | |
1263 | if (!ret) { | |
1264 | ret = -ERESTARTNOHAND; | |
1265 | if (signal_pending(current)) | |
1266 | goto out; | |
1267 | ret = 0; | |
1268 | } | |
1269 | ||
1270 | if (compat_set_fd_set(n, inp, fds.res_in) || | |
1271 | compat_set_fd_set(n, outp, fds.res_out) || | |
1272 | compat_set_fd_set(n, exp, fds.res_ex)) | |
1273 | ret = -EFAULT; | |
1274 | out: | |
1275 | if (bits != stack_fds) | |
1276 | kfree(bits); | |
1277 | out_nofds: | |
1278 | return ret; | |
1279 | } | |
1280 | ||
05585e44 DB |
1281 | static int do_compat_select(int n, compat_ulong_t __user *inp, |
1282 | compat_ulong_t __user *outp, compat_ulong_t __user *exp, | |
1283 | struct compat_timeval __user *tvp) | |
e99ca56c | 1284 | { |
36819ad0 | 1285 | struct timespec64 end_time, *to = NULL; |
e99ca56c AV |
1286 | struct compat_timeval tv; |
1287 | int ret; | |
1288 | ||
1289 | if (tvp) { | |
1290 | if (copy_from_user(&tv, tvp, sizeof(tv))) | |
1291 | return -EFAULT; | |
1292 | ||
1293 | to = &end_time; | |
1294 | if (poll_select_set_timeout(to, | |
1295 | tv.tv_sec + (tv.tv_usec / USEC_PER_SEC), | |
1296 | (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC)) | |
1297 | return -EINVAL; | |
1298 | } | |
1299 | ||
1300 | ret = compat_core_sys_select(n, inp, outp, exp, to); | |
1301 | ret = compat_poll_select_copy_remaining(&end_time, tvp, 1, ret); | |
1302 | ||
1303 | return ret; | |
1304 | } | |
1305 | ||
05585e44 DB |
1306 | COMPAT_SYSCALL_DEFINE5(select, int, n, compat_ulong_t __user *, inp, |
1307 | compat_ulong_t __user *, outp, compat_ulong_t __user *, exp, | |
1308 | struct compat_timeval __user *, tvp) | |
1309 | { | |
1310 | return do_compat_select(n, inp, outp, exp, tvp); | |
1311 | } | |
1312 | ||
e99ca56c AV |
1313 | struct compat_sel_arg_struct { |
1314 | compat_ulong_t n; | |
1315 | compat_uptr_t inp; | |
1316 | compat_uptr_t outp; | |
1317 | compat_uptr_t exp; | |
1318 | compat_uptr_t tvp; | |
1319 | }; | |
1320 | ||
1321 | COMPAT_SYSCALL_DEFINE1(old_select, struct compat_sel_arg_struct __user *, arg) | |
1322 | { | |
1323 | struct compat_sel_arg_struct a; | |
1324 | ||
1325 | if (copy_from_user(&a, arg, sizeof(a))) | |
1326 | return -EFAULT; | |
05585e44 DB |
1327 | return do_compat_select(a.n, compat_ptr(a.inp), compat_ptr(a.outp), |
1328 | compat_ptr(a.exp), compat_ptr(a.tvp)); | |
e99ca56c AV |
1329 | } |
1330 | ||
1331 | static long do_compat_pselect(int n, compat_ulong_t __user *inp, | |
1332 | compat_ulong_t __user *outp, compat_ulong_t __user *exp, | |
1333 | struct compat_timespec __user *tsp, compat_sigset_t __user *sigmask, | |
1334 | compat_size_t sigsetsize) | |
1335 | { | |
e99ca56c | 1336 | sigset_t ksigmask, sigsaved; |
36819ad0 | 1337 | struct timespec64 ts, end_time, *to = NULL; |
e99ca56c AV |
1338 | int ret; |
1339 | ||
1340 | if (tsp) { | |
36819ad0 | 1341 | if (compat_get_timespec64(&ts, tsp)) |
e99ca56c AV |
1342 | return -EFAULT; |
1343 | ||
1344 | to = &end_time; | |
1345 | if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) | |
1346 | return -EINVAL; | |
1347 | } | |
1348 | ||
1349 | if (sigmask) { | |
1350 | if (sigsetsize != sizeof(compat_sigset_t)) | |
1351 | return -EINVAL; | |
3968cf62 | 1352 | if (get_compat_sigset(&ksigmask, sigmask)) |
e99ca56c | 1353 | return -EFAULT; |
e99ca56c AV |
1354 | |
1355 | sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
1356 | sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); | |
1357 | } | |
1358 | ||
1359 | ret = compat_core_sys_select(n, inp, outp, exp, to); | |
1360 | ret = compat_poll_select_copy_remaining(&end_time, tsp, 0, ret); | |
1361 | ||
1362 | if (ret == -ERESTARTNOHAND) { | |
1363 | /* | |
1364 | * Don't restore the signal mask yet. Let do_signal() deliver | |
1365 | * the signal on the way back to userspace, before the signal | |
1366 | * mask is restored. | |
1367 | */ | |
1368 | if (sigmask) { | |
1369 | memcpy(¤t->saved_sigmask, &sigsaved, | |
1370 | sizeof(sigsaved)); | |
1371 | set_restore_sigmask(); | |
1372 | } | |
1373 | } else if (sigmask) | |
1374 | sigprocmask(SIG_SETMASK, &sigsaved, NULL); | |
1375 | ||
1376 | return ret; | |
1377 | } | |
1378 | ||
1379 | COMPAT_SYSCALL_DEFINE6(pselect6, int, n, compat_ulong_t __user *, inp, | |
1380 | compat_ulong_t __user *, outp, compat_ulong_t __user *, exp, | |
1381 | struct compat_timespec __user *, tsp, void __user *, sig) | |
1382 | { | |
1383 | compat_size_t sigsetsize = 0; | |
1384 | compat_uptr_t up = 0; | |
1385 | ||
1386 | if (sig) { | |
1387 | if (!access_ok(VERIFY_READ, sig, | |
1388 | sizeof(compat_uptr_t)+sizeof(compat_size_t)) || | |
1389 | __get_user(up, (compat_uptr_t __user *)sig) || | |
1390 | __get_user(sigsetsize, | |
1391 | (compat_size_t __user *)(sig+sizeof(up)))) | |
1392 | return -EFAULT; | |
1393 | } | |
1394 | return do_compat_pselect(n, inp, outp, exp, tsp, compat_ptr(up), | |
1395 | sigsetsize); | |
1396 | } | |
1397 | ||
1398 | COMPAT_SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, | |
1399 | unsigned int, nfds, struct compat_timespec __user *, tsp, | |
1400 | const compat_sigset_t __user *, sigmask, compat_size_t, sigsetsize) | |
1401 | { | |
e99ca56c | 1402 | sigset_t ksigmask, sigsaved; |
36819ad0 | 1403 | struct timespec64 ts, end_time, *to = NULL; |
e99ca56c AV |
1404 | int ret; |
1405 | ||
1406 | if (tsp) { | |
36819ad0 | 1407 | if (compat_get_timespec64(&ts, tsp)) |
e99ca56c AV |
1408 | return -EFAULT; |
1409 | ||
1410 | to = &end_time; | |
1411 | if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) | |
1412 | return -EINVAL; | |
1413 | } | |
1414 | ||
1415 | if (sigmask) { | |
1416 | if (sigsetsize != sizeof(compat_sigset_t)) | |
1417 | return -EINVAL; | |
3968cf62 | 1418 | if (get_compat_sigset(&ksigmask, sigmask)) |
e99ca56c | 1419 | return -EFAULT; |
e99ca56c AV |
1420 | |
1421 | sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
1422 | sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); | |
1423 | } | |
1424 | ||
1425 | ret = do_sys_poll(ufds, nfds, to); | |
1426 | ||
1427 | /* We can restart this syscall, usually */ | |
1428 | if (ret == -EINTR) { | |
1429 | /* | |
1430 | * Don't restore the signal mask yet. Let do_signal() deliver | |
1431 | * the signal on the way back to userspace, before the signal | |
1432 | * mask is restored. | |
1433 | */ | |
1434 | if (sigmask) { | |
1435 | memcpy(¤t->saved_sigmask, &sigsaved, | |
1436 | sizeof(sigsaved)); | |
1437 | set_restore_sigmask(); | |
1438 | } | |
1439 | ret = -ERESTARTNOHAND; | |
1440 | } else if (sigmask) | |
1441 | sigprocmask(SIG_SETMASK, &sigsaved, NULL); | |
1442 | ||
1443 | ret = compat_poll_select_copy_remaining(&end_time, tsp, 0, ret); | |
1444 | ||
1445 | return ret; | |
1446 | } | |
1447 | #endif |