1/* BSD-like signal function.
2 Copyright (C) 1991-2022 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
24sigset_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}
50weak_alias (__bsd_signal, bsd_signal)
51weak_alias (__bsd_signal, signal)
52weak_alias (__bsd_signal, ssignal)
53

source code of glibc/sysdeps/posix/signal.c