1/* Special use of signals internally. Linux version.
2 Copyright (C) 2014-2019 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
18
19#ifndef __INTERNAL_SIGNALS_H
20# define __INTERNAL_SIGNALS_H
21
22#include <signal.h>
23#include <sigsetops.h>
24#include <stdbool.h>
25#include <sysdep.h>
26
27/* The signal used for asynchronous cancelation. */
28#define SIGCANCEL __SIGRTMIN
29
30
31/* Signal needed for the kernel-supported POSIX timer implementation.
32 We can reuse the cancellation signal since we can distinguish
33 cancellation from timer expirations. */
34#define SIGTIMER SIGCANCEL
35
36
37/* Signal used to implement the setuid et.al. functions. */
38#define SIGSETXID (__SIGRTMIN + 1)
39
40
41/* Return is sig is used internally. */
42static inline bool
43__is_internal_signal (int sig)
44{
45 return (sig == SIGCANCEL) || (sig == SIGSETXID);
46}
47
48/* Remove internal glibc signal from the mask. */
49static inline void
50__clear_internal_signals (sigset_t *set)
51{
52 __sigdelset (set, SIGCANCEL);
53 __sigdelset (set, SIGSETXID);
54}
55
56#define SIGALL_SET \
57 ((__sigset_t) { .__val = {[0 ... _SIGSET_NWORDS-1 ] = -1 } })
58
59/* Block all signals, including internal glibc ones. */
60static inline int
61__libc_signal_block_all (sigset_t *set)
62{
63 INTERNAL_SYSCALL_DECL (err);
64 return INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_BLOCK, &SIGALL_SET,
65 set, _NSIG / 8);
66}
67
68/* Block all application signals (excluding internal glibc ones). */
69static inline int
70__libc_signal_block_app (sigset_t *set)
71{
72 sigset_t allset = SIGALL_SET;
73 __clear_internal_signals (&allset);
74 INTERNAL_SYSCALL_DECL (err);
75 return INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_BLOCK, &allset, set,
76 _NSIG / 8);
77}
78
79/* Restore current process signal mask. */
80static inline int
81__libc_signal_restore_set (const sigset_t *set)
82{
83 INTERNAL_SYSCALL_DECL (err);
84 return INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_SETMASK, set, NULL,
85 _NSIG / 8);
86}
87
88/* Used to communicate with signal handler. */
89extern struct xid_command *__xidcmd attribute_hidden;
90
91#endif
92