sigset.c 2.0 KB

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  1. /* Copyright (C) 1998, 2000, 2005 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 Lesser General Public
  5. License as published by the Free Software Foundation; either
  6. version 2.1 of the 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. Lesser General Public License for more details.
  11. You should have received a copy of the GNU Lesser General Public
  12. License along with the GNU C Library; if not, write to the Free
  13. Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  14. 02111-1307 USA. */
  15. #include <errno.h>
  16. #define __need_NULL
  17. #include <stddef.h>
  18. #include <signal.h>
  19. #include <string.h>
  20. /* Set the disposition for SIG. */
  21. __sighandler_t sigset (int sig, __sighandler_t disp)
  22. {
  23. struct sigaction act, oact;
  24. sigset_t set;
  25. /* Check signal extents to protect __sigismember. */
  26. if (disp == SIG_ERR || sig < 1 || sig >= NSIG)
  27. {
  28. __set_errno (EINVAL);
  29. return SIG_ERR;
  30. }
  31. #ifdef SIG_HOLD
  32. /* Handle SIG_HOLD first. */
  33. if (disp == SIG_HOLD)
  34. {
  35. __sigemptyset (&set);
  36. __sigaddset (&set, sig);
  37. /* Add the signal set to the current signal mask. */
  38. sigprocmask (SIG_BLOCK, &set, NULL); /* can't fail */
  39. return SIG_HOLD;
  40. }
  41. #endif /* SIG_HOLD */
  42. memset(&act, 0, sizeof(act));
  43. act.sa_handler = disp;
  44. /* In Linux (as of 2.6.25), fails only if sig is SIGKILL or SIGSTOP */
  45. if (sigaction (sig, &act, &oact) < 0)
  46. return SIG_ERR;
  47. /* Create an empty signal set. Add the specified signal. */
  48. __sigemptyset (&set);
  49. __sigaddset (&set, sig);
  50. /* Remove the signal set from the current signal mask. */
  51. sigprocmask (SIG_UNBLOCK, &set, NULL); /* can't fail */
  52. return oact.sa_handler;
  53. }