sysdeps/posix/sysv_signal.c

   1 /* Copyright (C) 1991-2024 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   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
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <signal.h>
  20 #include <string.h>     /* For the real memset prototype.  */
  21 #include <sigsetops.h>
  22
  23 /* Tolerate non-threads versions of Posix */
  24 #ifndef SA_ONESHOT
  25 #define SA_ONESHOT 0
  26 #endif
  27 #ifndef SA_NOMASK
  28 #define SA_NOMASK 0
  29 #endif
  30 #ifndef SA_INTERRUPT
  31 #define SA_INTERRUPT 0
  32 #endif
  33
  34 /* Set the handler for the signal SIG to HANDLER,
  35    returning the old handler, or SIG_ERR on error.  */
  36 __sighandler_t
  37 __sysv_signal (int sig, __sighandler_t handler)
  38 {
  39   struct sigaction act, oact;
  40
  41   /* Check signal extents to protect __sigismember.  */
  42   if (handler == SIG_ERR || sig < 1 || sig >= NSIG)
  43     {
  44       __set_errno (EINVAL);
  45       return SIG_ERR;
  46     }
  47
  48   act.sa_handler = handler;
  49   __sigemptyset (&act.sa_mask);
  50   act.sa_flags = SA_ONESHOT | SA_NOMASK | SA_INTERRUPT;
  51   act.sa_flags &= ~SA_RESTART;
  52   if (__sigaction (sig, &act, &oact) < 0)
  53     return SIG_ERR;
  54
  55   return oact.sa_handler;
  56 }
  57
  58 weak_alias (__sysv_signal, sysv_signal)