about summary refs log tree commit diff
path: root/sysdeps/mach/hurd/sigaltstack.c
blob: 44b019aaf267dd947b1c0dd2c380f74840139151 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
/* Copyright (C) 1992-2018 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#include <errno.h>
#include <hurd.h>
#include <hurd/signal.h>

/* Run signals handlers on the stack specified by SS (if not NULL).
   If OSS is not NULL, it is filled in with the old signal stack status.  */
int
__sigaltstack (const stack_t *argss, stack_t *oss)
{
  struct hurd_sigstate *s;
  stack_t ss, old;

  /* Fault before taking any locks.  */
  if (argss != NULL)
    ss = *argss;
  if (oss != NULL)
    *(volatile stack_t *) oss = *oss;

  s = _hurd_self_sigstate ();
  __spin_lock (&s->lock);

  if (argss != NULL &&
      (ss.ss_flags & SS_DISABLE) && (s->sigaltstack.ss_flags & SS_ONSTACK))
    {
      /* Can't disable a stack that is in use.  */
      __spin_unlock (&s->lock);
      errno = EINVAL;
      return -1;
    }

  old = s->sigaltstack;

  if (argss != NULL)
    s->sigaltstack = ss;

  __spin_unlock (&s->lock);

  if (oss != NULL)
    *oss = old;

  return 0;
}
libc_hidden_def (__sigaltstack)
weak_alias (__sigaltstack, sigaltstack)