1  /* BSD-like signal function.
       2     Copyright (C) 1991-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #include <errno.h>
      20  #include <signal.h>
      21  #include <sigsetops.h>
      22  #include <internal-signals.h>
      23  
      24  sigset_t _sigintr attribute_hidden;		/* Set by siginterrupt.  */
      25  
      26  /* Set the handler for the signal SIG to HANDLER,
      27     returning the old handler, or SIG_ERR on error.  */
      28  __sighandler_t
      29  __bsd_signal (int sig, __sighandler_t handler)
      30  {
      31    struct sigaction act, oact;
      32  
      33    /* Check signal extents to protect __sigismember.  */
      34    if (handler == SIG_ERR || sig < 1 || sig >= NSIG
      35        || is_internal_signal (sig))
      36      {
      37        __set_errno (EINVAL);
      38        return SIG_ERR;
      39      }
      40  
      41    act.sa_handler = handler;
      42    __sigemptyset (&act.sa_mask);
      43    __sigaddset (&act.sa_mask, sig);
      44    act.sa_flags = __sigismember (&_sigintr, sig) ? 0 : SA_RESTART;
      45    if (__sigaction (sig, &act, &oact) < 0)
      46      return SIG_ERR;
      47  
      48    return oact.sa_handler;
      49  }
      50  weak_alias (__bsd_signal, bsd_signal)
      51  weak_alias (__bsd_signal, signal)
      52  weak_alias (__bsd_signal, ssignal)