pselect.c 2.5 KB

12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667
  1. /* Copyright (C) 1996-1998,2001,2002,2003,2006 Free Software Foundation, Inc.
  2. This file is part of the GNU C Library.
  3. Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
  4. The GNU C Library is free software; you can redistribute it and/or
  5. modify it under the terms of the GNU Lesser General Public
  6. License as published by the Free Software Foundation; either
  7. version 2.1 of the License, or (at your option) any later version.
  8. The GNU C Library is distributed in the hope that it will be useful,
  9. but WITHOUT ANY WARRANTY; without even the implied warranty of
  10. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  11. Lesser General Public License for more details.
  12. You should have received a copy of the GNU Lesser General Public
  13. License along with the GNU C Library; if not, write to the Free
  14. Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  15. 02111-1307 USA. */
  16. #include <errno.h>
  17. #include <signal.h>
  18. #include <stddef.h> /* For NULL. */
  19. #include <sys/time.h>
  20. #include <sys/select.h>
  21. extern __typeof(pselect) __libc_pselect;
  22. /* Check the first NFDS descriptors each in READFDS (if not NULL) for read
  23. readiness, in WRITEFDS (if not NULL) for write readiness, and in EXCEPTFDS
  24. (if not NULL) for exceptional conditions. If TIMEOUT is not NULL, time out
  25. after waiting the interval specified therein. Additionally set the sigmask
  26. SIGMASK for this call. Returns the number of ready descriptors, or -1 for
  27. errors. */
  28. int
  29. __libc_pselect (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
  30. const struct timespec *timeout, const sigset_t *sigmask)
  31. {
  32. struct timeval tval;
  33. int retval;
  34. sigset_t savemask;
  35. /* Change nanosecond number to microseconds. This might mean losing
  36. precision and therefore the `pselect` should be available. But
  37. for now it is hardly found. */
  38. if (timeout != NULL)
  39. TIMESPEC_TO_TIMEVAL (&tval, timeout);
  40. /* The setting and restoring of the signal mask and the select call
  41. should be an atomic operation. This can't be done without kernel
  42. help. */
  43. if (sigmask != NULL)
  44. sigprocmask (SIG_SETMASK, sigmask, &savemask);
  45. /* Note the pselect() is a cancellation point. But since we call
  46. select() which itself is a cancellation point we do not have
  47. to do anything here. */
  48. retval = select (nfds, readfds, writefds, exceptfds,
  49. timeout != NULL ? &tval : NULL);
  50. if (sigmask != NULL)
  51. sigprocmask (SIG_SETMASK, &savemask, NULL);
  52. return retval;
  53. }
  54. weak_alias(__libc_pselect,pselect)