1 /* 2 * This file contains the procedures for the handling of select and poll 3 * 4 * Created for Linux based loosely upon Mathius Lattner's minix 5 * patches by Peter MacDonald. Heavily edited by Linus. 6 * 7 * 4 February 1994 8 * COFF/ELF binary emulation. If the process has the STICKY_TIMEOUTS 9 * flag set in its personality we do *not* modify the given timeout 10 * parameter to reflect time remaining. 11 * 12 * 24 January 2000 13 * Changed sys_poll()/do_poll() to use PAGE_SIZE chunk-based allocation 14 * of fds to overcome nfds < 16390 descriptors limit (Tigran Aivazian). 15 */ 16 17 #include <linux/syscalls.h> 18 #include <linux/module.h> 19 #include <linux/slab.h> 20 #include <linux/smp_lock.h> 21 #include <linux/poll.h> 22 #include <linux/personality.h> /* for STICKY_TIMEOUTS */ 23 #include <linux/file.h> 24 #include <linux/fs.h> 25 #include <linux/rcupdate.h> 26 27 #include <asm/uaccess.h> 28 29 #define ROUND_UP(x,y) (((x)+(y)-1)/(y)) 30 #define DEFAULT_POLLMASK (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM) 31 32 struct poll_table_page { 33 struct poll_table_page * next; 34 struct poll_table_entry * entry; 35 struct poll_table_entry entries[0]; 36 }; 37 38 #define POLL_TABLE_FULL(table) \ 39 ((unsigned long)((table)->entry+1) > PAGE_SIZE + (unsigned long)(table)) 40 41 /* 42 * Ok, Peter made a complicated, but straightforward multiple_wait() function. 43 * I have rewritten this, taking some shortcuts: This code may not be easy to 44 * follow, but it should be free of race-conditions, and it's practical. If you 45 * understand what I'm doing here, then you understand how the linux 46 * sleep/wakeup mechanism works. 47 * 48 * Two very simple procedures, poll_wait() and poll_freewait() make all the 49 * work. poll_wait() is an inline-function defined in <linux/poll.h>, 50 * as all select/poll functions have to call it to add an entry to the 51 * poll table. 52 */ 53 static void __pollwait(struct file *filp, wait_queue_head_t *wait_address, 54 poll_table *p); 55 56 void poll_initwait(struct poll_wqueues *pwq) 57 { 58 init_poll_funcptr(&pwq->pt, __pollwait); 59 pwq->error = 0; 60 pwq->table = NULL; 61 pwq->inline_index = 0; 62 } 63 64 EXPORT_SYMBOL(poll_initwait); 65 66 static void free_poll_entry(struct poll_table_entry *entry) 67 { 68 remove_wait_queue(entry->wait_address,&entry->wait); 69 fput(entry->filp); 70 } 71 72 void poll_freewait(struct poll_wqueues *pwq) 73 { 74 struct poll_table_page * p = pwq->table; 75 int i; 76 for (i = 0; i < pwq->inline_index; i++) 77 free_poll_entry(pwq->inline_entries + i); 78 while (p) { 79 struct poll_table_entry * entry; 80 struct poll_table_page *old; 81 82 entry = p->entry; 83 do { 84 entry--; 85 free_poll_entry(entry); 86 } while (entry > p->entries); 87 old = p; 88 p = p->next; 89 free_page((unsigned long) old); 90 } 91 } 92 93 EXPORT_SYMBOL(poll_freewait); 94 95 static struct poll_table_entry *poll_get_entry(poll_table *_p) 96 { 97 struct poll_wqueues *p = container_of(_p, struct poll_wqueues, pt); 98 struct poll_table_page *table = p->table; 99 100 if (p->inline_index < N_INLINE_POLL_ENTRIES) 101 return p->inline_entries + p->inline_index++; 102 103 if (!table || POLL_TABLE_FULL(table)) { 104 struct poll_table_page *new_table; 105 106 new_table = (struct poll_table_page *) __get_free_page(GFP_KERNEL); 107 if (!new_table) { 108 p->error = -ENOMEM; 109 __set_current_state(TASK_RUNNING); 110 return NULL; 111 } 112 new_table->entry = new_table->entries; 113 new_table->next = table; 114 p->table = new_table; 115 table = new_table; 116 } 117 118 return table->entry++; 119 } 120 121 /* Add a new entry */ 122 static void __pollwait(struct file *filp, wait_queue_head_t *wait_address, 123 poll_table *p) 124 { 125 struct poll_table_entry *entry = poll_get_entry(p); 126 if (!entry) 127 return; 128 get_file(filp); 129 entry->filp = filp; 130 entry->wait_address = wait_address; 131 init_waitqueue_entry(&entry->wait, current); 132 add_wait_queue(wait_address,&entry->wait); 133 } 134 135 #define FDS_IN(fds, n) (fds->in + n) 136 #define FDS_OUT(fds, n) (fds->out + n) 137 #define FDS_EX(fds, n) (fds->ex + n) 138 139 #define BITS(fds, n) (*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n)) 140 141 static int max_select_fd(unsigned long n, fd_set_bits *fds) 142 { 143 unsigned long *open_fds; 144 unsigned long set; 145 int max; 146 struct fdtable *fdt; 147 148 /* handle last in-complete long-word first */ 149 set = ~(~0UL << (n & (__NFDBITS-1))); 150 n /= __NFDBITS; 151 fdt = files_fdtable(current->files); 152 open_fds = fdt->open_fds->fds_bits+n; 153 max = 0; 154 if (set) { 155 set &= BITS(fds, n); 156 if (set) { 157 if (!(set & ~*open_fds)) 158 goto get_max; 159 return -EBADF; 160 } 161 } 162 while (n) { 163 open_fds--; 164 n--; 165 set = BITS(fds, n); 166 if (!set) 167 continue; 168 if (set & ~*open_fds) 169 return -EBADF; 170 if (max) 171 continue; 172 get_max: 173 do { 174 max++; 175 set >>= 1; 176 } while (set); 177 max += n * __NFDBITS; 178 } 179 180 return max; 181 } 182 183 #define BIT(i) (1UL << ((i)&(__NFDBITS-1))) 184 #define MEM(i,m) ((m)+(unsigned)(i)/__NFDBITS) 185 #define ISSET(i,m) (((i)&*(m)) != 0) 186 #define SET(i,m) (*(m) |= (i)) 187 188 #define POLLIN_SET (POLLRDNORM | POLLRDBAND | POLLIN | POLLHUP | POLLERR) 189 #define POLLOUT_SET (POLLWRBAND | POLLWRNORM | POLLOUT | POLLERR) 190 #define POLLEX_SET (POLLPRI) 191 192 int do_select(int n, fd_set_bits *fds, s64 *timeout) 193 { 194 struct poll_wqueues table; 195 poll_table *wait; 196 int retval, i; 197 198 rcu_read_lock(); 199 retval = max_select_fd(n, fds); 200 rcu_read_unlock(); 201 202 if (retval < 0) 203 return retval; 204 n = retval; 205 206 poll_initwait(&table); 207 wait = &table.pt; 208 if (!*timeout) 209 wait = NULL; 210 retval = 0; 211 for (;;) { 212 unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp; 213 long __timeout; 214 215 set_current_state(TASK_INTERRUPTIBLE); 216 217 inp = fds->in; outp = fds->out; exp = fds->ex; 218 rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex; 219 220 for (i = 0; i < n; ++rinp, ++routp, ++rexp) { 221 unsigned long in, out, ex, all_bits, bit = 1, mask, j; 222 unsigned long res_in = 0, res_out = 0, res_ex = 0; 223 const struct file_operations *f_op = NULL; 224 struct file *file = NULL; 225 226 in = *inp++; out = *outp++; ex = *exp++; 227 all_bits = in | out | ex; 228 if (all_bits == 0) { 229 i += __NFDBITS; 230 continue; 231 } 232 233 for (j = 0; j < __NFDBITS; ++j, ++i, bit <<= 1) { 234 int fput_needed; 235 if (i >= n) 236 break; 237 if (!(bit & all_bits)) 238 continue; 239 file = fget_light(i, &fput_needed); 240 if (file) { 241 f_op = file->f_op; 242 mask = DEFAULT_POLLMASK; 243 if (f_op && f_op->poll) 244 mask = (*f_op->poll)(file, retval ? NULL : wait); 245 fput_light(file, fput_needed); 246 if ((mask & POLLIN_SET) && (in & bit)) { 247 res_in |= bit; 248 retval++; 249 } 250 if ((mask & POLLOUT_SET) && (out & bit)) { 251 res_out |= bit; 252 retval++; 253 } 254 if ((mask & POLLEX_SET) && (ex & bit)) { 255 res_ex |= bit; 256 retval++; 257 } 258 } 259 cond_resched(); 260 } 261 if (res_in) 262 *rinp = res_in; 263 if (res_out) 264 *routp = res_out; 265 if (res_ex) 266 *rexp = res_ex; 267 } 268 wait = NULL; 269 if (retval || !*timeout || signal_pending(current)) 270 break; 271 if(table.error) { 272 retval = table.error; 273 break; 274 } 275 276 if (*timeout < 0) { 277 /* Wait indefinitely */ 278 __timeout = MAX_SCHEDULE_TIMEOUT; 279 } else if (unlikely(*timeout >= (s64)MAX_SCHEDULE_TIMEOUT - 1)) { 280 /* Wait for longer than MAX_SCHEDULE_TIMEOUT. Do it in a loop */ 281 __timeout = MAX_SCHEDULE_TIMEOUT - 1; 282 *timeout -= __timeout; 283 } else { 284 __timeout = *timeout; 285 *timeout = 0; 286 } 287 __timeout = schedule_timeout(__timeout); 288 if (*timeout >= 0) 289 *timeout += __timeout; 290 } 291 __set_current_state(TASK_RUNNING); 292 293 poll_freewait(&table); 294 295 return retval; 296 } 297 298 /* 299 * We can actually return ERESTARTSYS instead of EINTR, but I'd 300 * like to be certain this leads to no problems. So I return 301 * EINTR just for safety. 302 * 303 * Update: ERESTARTSYS breaks at least the xview clock binary, so 304 * I'm trying ERESTARTNOHAND which restart only when you want to. 305 */ 306 #define MAX_SELECT_SECONDS \ 307 ((unsigned long) (MAX_SCHEDULE_TIMEOUT / HZ)-1) 308 309 static int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp, 310 fd_set __user *exp, s64 *timeout) 311 { 312 fd_set_bits fds; 313 char *bits; 314 int ret, size, max_fdset; 315 struct fdtable *fdt; 316 /* Allocate small arguments on the stack to save memory and be faster */ 317 char stack_fds[SELECT_STACK_ALLOC]; 318 319 ret = -EINVAL; 320 if (n < 0) 321 goto out_nofds; 322 323 /* max_fdset can increase, so grab it once to avoid race */ 324 rcu_read_lock(); 325 fdt = files_fdtable(current->files); 326 max_fdset = fdt->max_fdset; 327 rcu_read_unlock(); 328 if (n > max_fdset) 329 n = max_fdset; 330 331 /* 332 * We need 6 bitmaps (in/out/ex for both incoming and outgoing), 333 * since we used fdset we need to allocate memory in units of 334 * long-words. 335 */ 336 ret = -ENOMEM; 337 size = FDS_BYTES(n); 338 if (6*size < SELECT_STACK_ALLOC) 339 bits = stack_fds; 340 else 341 bits = kmalloc(6 * size, GFP_KERNEL); 342 if (!bits) 343 goto out_nofds; 344 fds.in = (unsigned long *) bits; 345 fds.out = (unsigned long *) (bits + size); 346 fds.ex = (unsigned long *) (bits + 2*size); 347 fds.res_in = (unsigned long *) (bits + 3*size); 348 fds.res_out = (unsigned long *) (bits + 4*size); 349 fds.res_ex = (unsigned long *) (bits + 5*size); 350 351 if ((ret = get_fd_set(n, inp, fds.in)) || 352 (ret = get_fd_set(n, outp, fds.out)) || 353 (ret = get_fd_set(n, exp, fds.ex))) 354 goto out; 355 zero_fd_set(n, fds.res_in); 356 zero_fd_set(n, fds.res_out); 357 zero_fd_set(n, fds.res_ex); 358 359 ret = do_select(n, &fds, timeout); 360 361 if (ret < 0) 362 goto out; 363 if (!ret) { 364 ret = -ERESTARTNOHAND; 365 if (signal_pending(current)) 366 goto out; 367 ret = 0; 368 } 369 370 if (set_fd_set(n, inp, fds.res_in) || 371 set_fd_set(n, outp, fds.res_out) || 372 set_fd_set(n, exp, fds.res_ex)) 373 ret = -EFAULT; 374 375 out: 376 if (bits != stack_fds) 377 kfree(bits); 378 out_nofds: 379 return ret; 380 } 381 382 asmlinkage long sys_select(int n, fd_set __user *inp, fd_set __user *outp, 383 fd_set __user *exp, struct timeval __user *tvp) 384 { 385 s64 timeout = -1; 386 struct timeval tv; 387 int ret; 388 389 if (tvp) { 390 if (copy_from_user(&tv, tvp, sizeof(tv))) 391 return -EFAULT; 392 393 if (tv.tv_sec < 0 || tv.tv_usec < 0) 394 return -EINVAL; 395 396 /* Cast to u64 to make GCC stop complaining */ 397 if ((u64)tv.tv_sec >= (u64)MAX_INT64_SECONDS) 398 timeout = -1; /* infinite */ 399 else { 400 timeout = ROUND_UP(tv.tv_usec, USEC_PER_SEC/HZ); 401 timeout += tv.tv_sec * HZ; 402 } 403 } 404 405 ret = core_sys_select(n, inp, outp, exp, &timeout); 406 407 if (tvp) { 408 struct timeval rtv; 409 410 if (current->personality & STICKY_TIMEOUTS) 411 goto sticky; 412 rtv.tv_usec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)); 413 rtv.tv_sec = timeout; 414 if (timeval_compare(&rtv, &tv) >= 0) 415 rtv = tv; 416 if (copy_to_user(tvp, &rtv, sizeof(rtv))) { 417 sticky: 418 /* 419 * If an application puts its timeval in read-only 420 * memory, we don't want the Linux-specific update to 421 * the timeval to cause a fault after the select has 422 * completed successfully. However, because we're not 423 * updating the timeval, we can't restart the system 424 * call. 425 */ 426 if (ret == -ERESTARTNOHAND) 427 ret = -EINTR; 428 } 429 } 430 431 return ret; 432 } 433 434 #ifdef TIF_RESTORE_SIGMASK 435 asmlinkage long sys_pselect7(int n, fd_set __user *inp, fd_set __user *outp, 436 fd_set __user *exp, struct timespec __user *tsp, 437 const sigset_t __user *sigmask, size_t sigsetsize) 438 { 439 s64 timeout = MAX_SCHEDULE_TIMEOUT; 440 sigset_t ksigmask, sigsaved; 441 struct timespec ts; 442 int ret; 443 444 if (tsp) { 445 if (copy_from_user(&ts, tsp, sizeof(ts))) 446 return -EFAULT; 447 448 if (ts.tv_sec < 0 || ts.tv_nsec < 0) 449 return -EINVAL; 450 451 /* Cast to u64 to make GCC stop complaining */ 452 if ((u64)ts.tv_sec >= (u64)MAX_INT64_SECONDS) 453 timeout = -1; /* infinite */ 454 else { 455 timeout = ROUND_UP(ts.tv_nsec, NSEC_PER_SEC/HZ); 456 timeout += ts.tv_sec * HZ; 457 } 458 } 459 460 if (sigmask) { 461 /* XXX: Don't preclude handling different sized sigset_t's. */ 462 if (sigsetsize != sizeof(sigset_t)) 463 return -EINVAL; 464 if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask))) 465 return -EFAULT; 466 467 sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP)); 468 sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); 469 } 470 471 ret = core_sys_select(n, inp, outp, exp, &timeout); 472 473 if (tsp) { 474 struct timespec rts; 475 476 if (current->personality & STICKY_TIMEOUTS) 477 goto sticky; 478 rts.tv_nsec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)) * 479 1000; 480 rts.tv_sec = timeout; 481 if (timespec_compare(&rts, &ts) >= 0) 482 rts = ts; 483 if (copy_to_user(tsp, &rts, sizeof(rts))) { 484 sticky: 485 /* 486 * If an application puts its timeval in read-only 487 * memory, we don't want the Linux-specific update to 488 * the timeval to cause a fault after the select has 489 * completed successfully. However, because we're not 490 * updating the timeval, we can't restart the system 491 * call. 492 */ 493 if (ret == -ERESTARTNOHAND) 494 ret = -EINTR; 495 } 496 } 497 498 if (ret == -ERESTARTNOHAND) { 499 /* 500 * Don't restore the signal mask yet. Let do_signal() deliver 501 * the signal on the way back to userspace, before the signal 502 * mask is restored. 503 */ 504 if (sigmask) { 505 memcpy(¤t->saved_sigmask, &sigsaved, 506 sizeof(sigsaved)); 507 set_thread_flag(TIF_RESTORE_SIGMASK); 508 } 509 } else if (sigmask) 510 sigprocmask(SIG_SETMASK, &sigsaved, NULL); 511 512 return ret; 513 } 514 515 /* 516 * Most architectures can't handle 7-argument syscalls. So we provide a 517 * 6-argument version where the sixth argument is a pointer to a structure 518 * which has a pointer to the sigset_t itself followed by a size_t containing 519 * the sigset size. 520 */ 521 asmlinkage long sys_pselect6(int n, fd_set __user *inp, fd_set __user *outp, 522 fd_set __user *exp, struct timespec __user *tsp, void __user *sig) 523 { 524 size_t sigsetsize = 0; 525 sigset_t __user *up = NULL; 526 527 if (sig) { 528 if (!access_ok(VERIFY_READ, sig, sizeof(void *)+sizeof(size_t)) 529 || __get_user(up, (sigset_t __user * __user *)sig) 530 || __get_user(sigsetsize, 531 (size_t __user *)(sig+sizeof(void *)))) 532 return -EFAULT; 533 } 534 535 return sys_pselect7(n, inp, outp, exp, tsp, up, sigsetsize); 536 } 537 #endif /* TIF_RESTORE_SIGMASK */ 538 539 struct poll_list { 540 struct poll_list *next; 541 int len; 542 struct pollfd entries[0]; 543 }; 544 545 #define POLLFD_PER_PAGE ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd)) 546 547 static void do_pollfd(unsigned int num, struct pollfd * fdpage, 548 poll_table ** pwait, int *count) 549 { 550 int i; 551 552 for (i = 0; i < num; i++) { 553 int fd; 554 unsigned int mask; 555 struct pollfd *fdp; 556 557 mask = 0; 558 fdp = fdpage+i; 559 fd = fdp->fd; 560 if (fd >= 0) { 561 int fput_needed; 562 struct file * file = fget_light(fd, &fput_needed); 563 mask = POLLNVAL; 564 if (file != NULL) { 565 mask = DEFAULT_POLLMASK; 566 if (file->f_op && file->f_op->poll) 567 mask = file->f_op->poll(file, *pwait); 568 mask &= fdp->events | POLLERR | POLLHUP; 569 fput_light(file, fput_needed); 570 } 571 if (mask) { 572 *pwait = NULL; 573 (*count)++; 574 } 575 } 576 fdp->revents = mask; 577 } 578 } 579 580 static int do_poll(unsigned int nfds, struct poll_list *list, 581 struct poll_wqueues *wait, s64 *timeout) 582 { 583 int count = 0; 584 poll_table* pt = &wait->pt; 585 586 /* Optimise the no-wait case */ 587 if (!(*timeout)) 588 pt = NULL; 589 590 for (;;) { 591 struct poll_list *walk; 592 long __timeout; 593 594 set_current_state(TASK_INTERRUPTIBLE); 595 walk = list; 596 while(walk != NULL) { 597 do_pollfd( walk->len, walk->entries, &pt, &count); 598 walk = walk->next; 599 } 600 pt = NULL; 601 if (count || !*timeout || signal_pending(current)) 602 break; 603 count = wait->error; 604 if (count) 605 break; 606 607 if (*timeout < 0) { 608 /* Wait indefinitely */ 609 __timeout = MAX_SCHEDULE_TIMEOUT; 610 } else if (unlikely(*timeout >= (s64)MAX_SCHEDULE_TIMEOUT-1)) { 611 /* 612 * Wait for longer than MAX_SCHEDULE_TIMEOUT. Do it in 613 * a loop 614 */ 615 __timeout = MAX_SCHEDULE_TIMEOUT - 1; 616 *timeout -= __timeout; 617 } else { 618 __timeout = *timeout; 619 *timeout = 0; 620 } 621 622 __timeout = schedule_timeout(__timeout); 623 if (*timeout >= 0) 624 *timeout += __timeout; 625 } 626 __set_current_state(TASK_RUNNING); 627 return count; 628 } 629 630 #define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \ 631 sizeof(struct pollfd)) 632 633 int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds, s64 *timeout) 634 { 635 struct poll_wqueues table; 636 int fdcount, err; 637 unsigned int i; 638 struct poll_list *head; 639 struct poll_list *walk; 640 struct fdtable *fdt; 641 int max_fdset; 642 /* Allocate small arguments on the stack to save memory and be faster */ 643 char stack_pps[POLL_STACK_ALLOC]; 644 struct poll_list *stack_pp = NULL; 645 646 /* Do a sanity check on nfds ... */ 647 rcu_read_lock(); 648 fdt = files_fdtable(current->files); 649 max_fdset = fdt->max_fdset; 650 rcu_read_unlock(); 651 if (nfds > max_fdset && nfds > OPEN_MAX) 652 return -EINVAL; 653 654 poll_initwait(&table); 655 656 head = NULL; 657 walk = NULL; 658 i = nfds; 659 err = -ENOMEM; 660 while(i!=0) { 661 struct poll_list *pp; 662 int num, size; 663 if (stack_pp == NULL) 664 num = N_STACK_PPS; 665 else 666 num = POLLFD_PER_PAGE; 667 if (num > i) 668 num = i; 669 size = sizeof(struct poll_list) + sizeof(struct pollfd)*num; 670 if (!stack_pp) 671 stack_pp = pp = (struct poll_list *)stack_pps; 672 else { 673 pp = kmalloc(size, GFP_KERNEL); 674 if (!pp) 675 goto out_fds; 676 } 677 pp->next=NULL; 678 pp->len = num; 679 if (head == NULL) 680 head = pp; 681 else 682 walk->next = pp; 683 684 walk = pp; 685 if (copy_from_user(pp->entries, ufds + nfds-i, 686 sizeof(struct pollfd)*num)) { 687 err = -EFAULT; 688 goto out_fds; 689 } 690 i -= pp->len; 691 } 692 693 fdcount = do_poll(nfds, head, &table, timeout); 694 695 /* OK, now copy the revents fields back to user space. */ 696 walk = head; 697 err = -EFAULT; 698 while(walk != NULL) { 699 struct pollfd *fds = walk->entries; 700 int j; 701 702 for (j=0; j < walk->len; j++, ufds++) { 703 if(__put_user(fds[j].revents, &ufds->revents)) 704 goto out_fds; 705 } 706 walk = walk->next; 707 } 708 err = fdcount; 709 if (!fdcount && signal_pending(current)) 710 err = -EINTR; 711 out_fds: 712 walk = head; 713 while(walk!=NULL) { 714 struct poll_list *pp = walk->next; 715 if (walk != stack_pp) 716 kfree(walk); 717 walk = pp; 718 } 719 poll_freewait(&table); 720 return err; 721 } 722 723 asmlinkage long sys_poll(struct pollfd __user *ufds, unsigned int nfds, 724 long timeout_msecs) 725 { 726 s64 timeout_jiffies = 0; 727 728 if (timeout_msecs) { 729 #if HZ > 1000 730 /* We can only overflow if HZ > 1000 */ 731 if (timeout_msecs / 1000 > (s64)0x7fffffffffffffffULL / (s64)HZ) 732 timeout_jiffies = -1; 733 else 734 #endif 735 timeout_jiffies = msecs_to_jiffies(timeout_msecs); 736 } 737 738 return do_sys_poll(ufds, nfds, &timeout_jiffies); 739 } 740 741 #ifdef TIF_RESTORE_SIGMASK 742 asmlinkage long sys_ppoll(struct pollfd __user *ufds, unsigned int nfds, 743 struct timespec __user *tsp, const sigset_t __user *sigmask, 744 size_t sigsetsize) 745 { 746 sigset_t ksigmask, sigsaved; 747 struct timespec ts; 748 s64 timeout = -1; 749 int ret; 750 751 if (tsp) { 752 if (copy_from_user(&ts, tsp, sizeof(ts))) 753 return -EFAULT; 754 755 /* Cast to u64 to make GCC stop complaining */ 756 if ((u64)ts.tv_sec >= (u64)MAX_INT64_SECONDS) 757 timeout = -1; /* infinite */ 758 else { 759 timeout = ROUND_UP(ts.tv_nsec, NSEC_PER_SEC/HZ); 760 timeout += ts.tv_sec * HZ; 761 } 762 } 763 764 if (sigmask) { 765 /* XXX: Don't preclude handling different sized sigset_t's. */ 766 if (sigsetsize != sizeof(sigset_t)) 767 return -EINVAL; 768 if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask))) 769 return -EFAULT; 770 771 sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP)); 772 sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved); 773 } 774 775 ret = do_sys_poll(ufds, nfds, &timeout); 776 777 /* We can restart this syscall, usually */ 778 if (ret == -EINTR) { 779 /* 780 * Don't restore the signal mask yet. Let do_signal() deliver 781 * the signal on the way back to userspace, before the signal 782 * mask is restored. 783 */ 784 if (sigmask) { 785 memcpy(¤t->saved_sigmask, &sigsaved, 786 sizeof(sigsaved)); 787 set_thread_flag(TIF_RESTORE_SIGMASK); 788 } 789 ret = -ERESTARTNOHAND; 790 } else if (sigmask) 791 sigprocmask(SIG_SETMASK, &sigsaved, NULL); 792 793 if (tsp && timeout >= 0) { 794 struct timespec rts; 795 796 if (current->personality & STICKY_TIMEOUTS) 797 goto sticky; 798 /* Yes, we know it's actually an s64, but it's also positive. */ 799 rts.tv_nsec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)) * 800 1000; 801 rts.tv_sec = timeout; 802 if (timespec_compare(&rts, &ts) >= 0) 803 rts = ts; 804 if (copy_to_user(tsp, &rts, sizeof(rts))) { 805 sticky: 806 /* 807 * If an application puts its timeval in read-only 808 * memory, we don't want the Linux-specific update to 809 * the timeval to cause a fault after the select has 810 * completed successfully. However, because we're not 811 * updating the timeval, we can't restart the system 812 * call. 813 */ 814 if (ret == -ERESTARTNOHAND && timeout >= 0) 815 ret = -EINTR; 816 } 817 } 818 819 return ret; 820 } 821 #endif /* TIF_RESTORE_SIGMASK */ 822