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. */ |
42 | static 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. */ |
49 | static 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. */ |
60 | static 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). */ |
69 | static 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. */ |
80 | static 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. */ |
89 | extern struct xid_command *__xidcmd attribute_hidden; |
90 | |
91 | #endif |
92 | |