glibc/sysdeps/unix/sysv/linux/internal-signals.h
Adhemerval Zanella a1bdd81664 Refactor internal-signals.h
The main drive is to optimize the internal usage and required size
when sigset_t is embedded in other data structures.  On Linux, the
current supported signal set requires up to 8 bytes (16 on mips),
was lower than the user defined sigset_t (128 bytes).

A new internal type internal_sigset_t is added, along with the
functions to operate on it similar to the ones for sigset_t.  The
internal-signals.h is also refactored to remove unused functions

Besides small stack usage on some functions (posix_spawn, abort)
it lower the struct pthread by about 120 bytes (112 on mips).

Checked on x86_64-linux-gnu.

Reviewed-by: Arjun Shankar <arjun@redhat.com>
2022-06-30 14:56:21 -03:00

111 lines
3.1 KiB
C

/* Special use of signals internally. Linux version.
Copyright (C) 2014-2022 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 <internal-sigset.h>
#include <limits.h>
#include <signal.h>
#include <sigsetops.h>
#include <stdbool.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 internal_sigset_t sigall_set = {
.__val = {[0 ... __NSIG_WORDS-1 ] = -1 }
};
/* Obtain and change blocked signals, including internal glibc ones. */
static inline int
internal_sigprocmask (int how, const internal_sigset_t *set,
internal_sigset_t *oldset)
{
return INTERNAL_SYSCALL_CALL (rt_sigprocmask, how, set, oldset,
__NSIG_BYTES);
}
/* Block all signals, including internal glibc ones. */
static inline void
internal_signal_block_all (internal_sigset_t *oset)
{
INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_BLOCK, &sigall_set, oset,
__NSIG_BYTES);
}
/* Restore current process signal mask. */
static inline void
internal_signal_restore_set (const internal_sigset_t *set)
{
INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_SETMASK, set, NULL,
__NSIG_BYTES);
}
/* It is used on timer_create code directly on sigwaitinfo call, so it can not
use the internal_sigset_t definitions. */
static const sigset_t sigtimer_set = {
.__val = { [0] = __sigmask (SIGTIMER),
[1 ... _SIGSET_NWORDS-1] = 0
}
};
/* Unblock only SIGTIMER. */
static inline void
signal_unblock_sigtimer (void)
{
INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_UNBLOCK, &sigtimer_set, NULL,
__NSIG_BYTES);
}
#endif