sysv_signal.c 1.7 KB

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  1. /* Copyright (C) 1991, 1992, 1996, 1997 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. #include <signal.h>
  17. /* Tolerate non-threads versions of Posix */
  18. #ifndef SA_ONESHOT
  19. #define SA_ONESHOT 0
  20. #endif
  21. #ifndef SA_NOMASK
  22. #define SA_NOMASK 0
  23. #endif
  24. #ifndef SA_INTERRUPT
  25. #define SA_INTERRUPT 0
  26. #endif
  27. /* Set the handler for the signal SIG to HANDLER,
  28. returning the old handler, or SIG_ERR on error. */
  29. __sighandler_t sysv_signal (int sig, __sighandler_t handler)
  30. {
  31. struct sigaction act, oact;
  32. /* Check signal extents to protect __sigismember. */
  33. if (handler == SIG_ERR || sig < 1 || sig >= NSIG)
  34. {
  35. __set_errno (EINVAL);
  36. return SIG_ERR;
  37. }
  38. act.sa_handler = handler;
  39. if (__sigemptyset (&act.sa_mask) < 0)
  40. return SIG_ERR;
  41. act.sa_flags = SA_ONESHOT | SA_NOMASK | SA_INTERRUPT;
  42. act.sa_flags &= ~SA_RESTART;
  43. if (sigaction (sig, &act, &oact) < 0)
  44. return SIG_ERR;
  45. return oact.sa_handler;
  46. }