1/* Copyright (C) 1994-2024 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 <hurd/sigpreempt.h>
19#include <hurd/signal.h>
20#include <assert.h>
21
22void
23hurd_preempt_signals (struct hurd_signal_preemptor *preemptor)
24{
25 __mutex_lock (&_hurd_siglock);
26 preemptor->next = _hurdsig_preemptors;
27 _hurdsig_preemptors = preemptor;
28 _hurdsig_preempted_set |= preemptor->signals;
29 __mutex_unlock (&_hurd_siglock);
30}
31
32void
33hurd_unpreempt_signals (struct hurd_signal_preemptor *preemptor)
34{
35 struct hurd_signal_preemptor **p;
36 sigset_t preempted = 0;
37
38 __mutex_lock (&_hurd_siglock);
39
40 p = &_hurdsig_preemptors;
41 while (*p)
42 if (*p == preemptor)
43 {
44 /* Found it; take it off the chain. */
45 *p = (*p)->next;
46 if ((preemptor->signals & preempted) != preemptor->signals)
47 {
48 /* This might have been the only preemptor for some
49 of those signals, so we must collect the full mask
50 from the others. */
51 struct hurd_signal_preemptor *pp;
52 for (pp = *p; pp; pp = pp->next)
53 preempted |= pp->signals;
54 _hurdsig_preempted_set = preempted;
55 }
56 __mutex_unlock (&_hurd_siglock);
57 return;
58 }
59 else
60 {
61 preempted |= (*p)->signals;
62 p = &(*p)->next;
63 }
64
65 __mutex_unlock (&_hurd_siglock); /* Avoid deadlock during death rattle. */
66 assert (! "removing absent preemptor");
67}
68

source code of glibc/hurd/preempt-sig.c