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1/* Implementation of sigwait function from POSIX.1c.
2 Copyright (C) 1996-2019 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <http://www.gnu.org/licenses/>. */
19
20#include <errno.h>
21#include <signal.h>
22#include <stddef.h> /* For NULL. */
23#include <sysdep-cancel.h>
24
25/* This is our dummy signal handler we use here. */
26static void ignore_signal (int sig);
27
28/* Place where to remember which signal we got. Please note that this
29 implementation cannot be used for the threaded libc. The
30 libpthread must provide an own version. */
31static int was_sig;
32
33
34static int
35do_sigwait (const sigset_t *set, int *sig)
36{
37 sigset_t tmp_mask;
38 struct sigaction saved[NSIG];
39 struct sigaction action;
40 int save_errno;
41 int this;
42
43 /* Prepare set. */
44 __sigfillset (&tmp_mask);
45
46 /* Unblock all signals in the SET and register our nice handler. */
47 action.sa_handler = ignore_signal;
48 action.sa_flags = 0;
49 __sigfillset (&action.sa_mask); /* Block all signals for handler. */
50
51 /* Make sure we recognize error conditions by setting WAS_SIG to a
52 value which does not describe a legal signal number. */
53 was_sig = -1;
54
55 for (this = 1; this < NSIG; ++this)
56 if (__sigismember (set, this))
57 {
58 /* Unblock this signal. */
59 __sigdelset (&tmp_mask, this);
60
61 /* Register temporary action handler. */
62 if (__sigaction (this, &action, &saved[this]) != 0)
63 goto restore_handler;
64 }
65
66 /* Now we can wait for signals. */
67 __sigsuspend (&tmp_mask);
68
69 restore_handler:
70 save_errno = errno;
71
72 while (--this >= 1)
73 if (__sigismember (set, this))
74 /* We ignore errors here since we must restore all handlers. */
75 __sigaction (this, &saved[this], NULL);
76
77 __set_errno (save_errno);
78
79 /* Store the result and return. */
80 *sig = was_sig;
81 return was_sig == -1 ? -1 : 0;
82}
83
84
85int
86__sigwait (const sigset_t *set, int *sig)
87{
88 /* __sigsuspend should be a cancellation point. */
89 return do_sigitid (idtype, id, infop, options);
90}
91libc_hidden_def (__sigwait)
92weak_alias (__sigwait, sigwait)
93
94
95static void
96ignore_signal (int sig)
97{
98 /* Remember the signal. */
99 was_sig = sig;
100}
101

Warning: That file was not part of the compilation database. It may have many parsing errors.