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/* Special use of signals internally. Linux version.
Copyright (C) 2014-2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#ifndef __INTERNAL_SIGNALS_H
# define __INTERNAL_SIGNALS_H
#include <signal.h>
#include <sigsetops.h>
#include <stdbool.h>
#include <limits.h>
#include <stddef.h>
#include <sysdep.h>
/* The signal used for asynchronous cancelation. */
#define SIGCANCEL __SIGRTMIN
/* Signal needed for the kernel-supported POSIX timer implementation.
We can reuse the cancellation signal since we can distinguish
cancellation from timer expirations. */
#define SIGTIMER SIGCANCEL
/* Signal used to implement the setuid et.al. functions. */
#define SIGSETXID (__SIGRTMIN + 1)
/* How many signal numbers need to be reserved for libpthread's private uses
(SIGCANCEL and SIGSETXID). */
#define RESERVED_SIGRT 2
/* Return is sig is used internally. */
static inline bool
__is_internal_signal (int sig)
{
return (sig == SIGCANCEL) || (sig == SIGSETXID);
}
/* Remove internal glibc signal from the mask. */
static inline void
__clear_internal_signals (sigset_t *set)
{
__sigdelset (set, SIGCANCEL);
__sigdelset (set, SIGSETXID);
}
static const sigset_t sigall_set = {
.__val = {[0 ... _SIGSET_NWORDS-1 ] = -1 }
};
static const sigset_t sigtimer_set = {
.__val = { [0] = __sigmask (SIGTIMER),
[1 ... _SIGSET_NWORDS-1] = 0 }
};
/* Block all signals, including internal glibc ones. */
static inline void
__libc_signal_block_all (sigset_t *set)
{
INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_BLOCK, &sigall_set, set,
__NSIG_BYTES);
}
/* Block all application signals (excluding internal glibc ones). */
static inline void
__libc_signal_block_app (sigset_t *set)
{
sigset_t allset = sigall_set;
__clear_internal_signals (&allset);
INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_BLOCK, &allset, set,
__NSIG_BYTES);
}
/* Block only SIGTIMER and return the previous set on SET. */
static inline void
__libc_signal_block_sigtimer (sigset_t *set)
{
INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_BLOCK, &sigtimer_set, set,
__NSIG_BYTES);
}
/* Unblock only SIGTIMER and return the previous set on SET. */
static inline void
__libc_signal_unblock_sigtimer (sigset_t *set)
{
INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_UNBLOCK, &sigtimer_set, set,
__NSIG_BYTES);
}
/* Restore current process signal mask. */
static inline void
__libc_signal_restore_set (const sigset_t *set)
{
INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_SETMASK, set, NULL,
__NSIG_BYTES);
}
#endif
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