1/* Copyright (C) 1991-2022 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
58weak_alias (__sysv_signal, sysv_signal)
59

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