1/* Special use of signals in NPTL internals. Linux version.
2 Copyright (C) 2014-2017 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#include <signal.h>
20#include <sigsetops.h>
21
22/* The signal used for asynchronous cancelation. */
23#define SIGCANCEL __SIGRTMIN
24
25
26/* Signal needed for the kernel-supported POSIX timer implementation.
27 We can reuse the cancellation signal since we can distinguish
28 cancellation from timer expirations. */
29#define SIGTIMER SIGCANCEL
30
31
32/* Signal used to implement the setuid et.al. functions. */
33#define SIGSETXID (__SIGRTMIN + 1)
34
35
36/* Return is sig is used internally. */
37static inline int
38__nptl_is_internal_signal (int sig)
39{
40 return (sig == SIGCANCEL) || (sig == SIGTIMER) || (sig == SIGSETXID);
41}
42
43/* Remove internal glibc signal from the mask. */
44static inline void
45__nptl_clear_internal_signals (sigset_t *set)
46{
47 __sigdelset (set, SIGCANCEL);
48 __sigdelset (set, SIGTIMER);
49 __sigdelset (set, SIGSETXID);
50}
51
52#define SIGALL_SET \
53 ((__sigset_t) { .__val = {[0 ... _SIGSET_NWORDS-1 ] = -1 } })
54
55/* Block all signals, including internal glibc ones. */
56static inline int
57__libc_signal_block_all (sigset_t *set)
58{
59 INTERNAL_SYSCALL_DECL (err);
60 return INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_BLOCK, &SIGALL_SET,
61 set, _NSIG / 8);
62}
63
64/* Block all application signals (excluding internal glibc ones). */
65static inline int
66__libc_signal_block_app (sigset_t *set)
67{
68 sigset_t allset = SIGALL_SET;
69 __nptl_clear_internal_signals (&allset);
70 INTERNAL_SYSCALL_DECL (err);
71 return INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_BLOCK, &allset, set,
72 _NSIG / 8);
73}
74
75/* Restore current process signal mask. */
76static inline int
77__libc_signal_restore_set (const sigset_t *set)
78{
79 INTERNAL_SYSCALL_DECL (err);
80 return INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_SETMASK, set, NULL,
81 _NSIG / 8);
82}
83
84/* Used to communicate with signal handler. */
85extern struct xid_command *__xidcmd attribute_hidden;
86