sigset.c 2.2 KB

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  1. /* Copyright (C) 1998, 2000 Free Software Foundation, Inc.
  2. This file is part of the GNU C Library.
  3. The GNU C Library is free software; you can redistribute it and/or
  4. modify it under the terms of the GNU Library General Public License as
  5. published by the Free Software Foundation; either version 2 of the
  6. License, or (at your option) any later version.
  7. The GNU C Library is distributed in the hope that it will be useful,
  8. but WITHOUT ANY WARRANTY; without even the implied warranty of
  9. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  10. Library General Public License for more details.
  11. You should have received a copy of the GNU Library General Public
  12. License along with the GNU C Library; see the file COPYING.LIB. If not,
  13. write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  14. Boston, MA 02111-1307, USA. */
  15. #include <errno.h>
  16. #define __need_NULL
  17. #include <stddef.h>
  18. #include <signal.h>
  19. /* Set the disposition for SIG. */
  20. __sighandler_t sigset (int sig, __sighandler_t disp)
  21. {
  22. struct sigaction act, oact;
  23. sigset_t set;
  24. #ifdef SIG_HOLD
  25. /* Handle SIG_HOLD first. */
  26. if (disp == SIG_HOLD)
  27. {
  28. /* Create an empty signal set. */
  29. if (__sigemptyset (&set) < 0)
  30. return SIG_ERR;
  31. /* Add the specified signal. */
  32. if (__sigaddset (&set, sig) < 0)
  33. return SIG_ERR;
  34. /* Add the signal set to the current signal mask. */
  35. if (__sigprocmask (SIG_BLOCK, &set, NULL) < 0)
  36. return SIG_ERR;
  37. return SIG_HOLD;
  38. }
  39. #endif /* SIG_HOLD */
  40. /* Check signal extents to protect __sigismember. */
  41. if (disp == SIG_ERR || sig < 1 || sig >= NSIG)
  42. {
  43. __set_errno (EINVAL);
  44. return SIG_ERR;
  45. }
  46. act.sa_handler = disp;
  47. if (__sigemptyset (&act.sa_mask) < 0)
  48. return SIG_ERR;
  49. act.sa_flags = 0;
  50. if (sigaction (sig, &act, &oact) < 0)
  51. return SIG_ERR;
  52. /* Create an empty signal set. */
  53. if (__sigemptyset (&set) < 0)
  54. return SIG_ERR;
  55. /* Add the specified signal. */
  56. if (__sigaddset (&set, sig) < 0)
  57. return SIG_ERR;
  58. /* Remove the signal set from the current signal mask. */
  59. if (sigprocmask (SIG_UNBLOCK, &set, NULL) < 0)
  60. return SIG_ERR;
  61. return oact.sa_handler;
  62. }