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19361cb7 | 1 | /* Implementation of sigwait function from POSIX.1c. |
04277e02 | 2 | Copyright (C) 1996-2019 Free Software Foundation, Inc. |
ba1ffaa1 UD |
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 | |
41bdb6e2 AJ |
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. | |
ba1ffaa1 UD |
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 | |
41bdb6e2 | 14 | Lesser General Public License for more details. |
ba1ffaa1 | 15 | |
41bdb6e2 | 16 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 | 17 | License along with the GNU C Library; if not, see |
5a82c748 | 18 | <https://www.gnu.org/licenses/>. */ |
ba1ffaa1 | 19 | |
ba1ffaa1 UD |
20 | #include <errno.h> |
21 | #include <signal.h> | |
19361cb7 | 22 | #include <stddef.h> /* For NULL. */ |
6ee8d334 | 23 | #include <sysdep-cancel.h> |
ba1ffaa1 UD |
24 | |
25 | /* This is our dummy signal handler we use here. */ | |
26 | static 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. */ | |
31 | static int was_sig; | |
32 | ||
33 | ||
6ee8d334 UD |
34 | static int |
35 | do_sigwait (const sigset_t *set, int *sig) | |
ba1ffaa1 UD |
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. */ | |
84384f5b | 44 | __sigfillset (&tmp_mask); |
ba1ffaa1 UD |
45 | |
46 | /* Unblock all signals in the SET and register our nice handler. */ | |
47 | action.sa_handler = ignore_signal; | |
48 | action.sa_flags = 0; | |
84384f5b | 49 | __sigfillset (&action.sa_mask); /* Block all signals for handler. */ |
ba1ffaa1 UD |
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 | ||
ec91ea7c | 55 | for (this = 1; this < NSIG; ++this) |
84384f5b | 56 | if (__sigismember (set, this)) |
ba1ffaa1 UD |
57 | { |
58 | /* Unblock this signal. */ | |
84384f5b | 59 | __sigdelset (&tmp_mask, this); |
ba1ffaa1 UD |
60 | |
61 | /* Register temporary action handler. */ | |
84384f5b | 62 | if (__sigaction (this, &action, &saved[this]) != 0) |
ba1ffaa1 UD |
63 | goto restore_handler; |
64 | } | |
65 | ||
66 | /* Now we can wait for signals. */ | |
84384f5b | 67 | __sigsuspend (&tmp_mask); |
ba1ffaa1 UD |
68 | |
69 | restore_handler: | |
70 | save_errno = errno; | |
71 | ||
ec91ea7c | 72 | while (--this >= 1) |
84384f5b | 73 | if (__sigismember (set, this)) |
ba1ffaa1 | 74 | /* We ignore errors here since we must restore all handlers. */ |
84384f5b | 75 | __sigaction (this, &saved[this], NULL); |
ba1ffaa1 UD |
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 | } | |
6ee8d334 UD |
83 | |
84 | ||
85 | int | |
86 | __sigwait (const sigset_t *set, int *sig) | |
87 | { | |
ce7eb0e9 AZ |
88 | /* __sigsuspend should be a cancellation point. */ |
89 | return do_sigitid (idtype, id, infop, options); | |
6ee8d334 | 90 | } |
bf2cc5fb | 91 | libc_hidden_def (__sigwait) |
ba1ffaa1 UD |
92 | weak_alias (__sigwait, sigwait) |
93 | ||
94 | ||
95 | static void | |
96 | ignore_signal (int sig) | |
97 | { | |
98 | /* Remember the signal. */ | |
99 | was_sig = sig; | |
100 | } |