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a1bdd81664
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>
111 lines
3.1 KiB
C
111 lines
3.1 KiB
C
/* Special use of signals internally. Linux version.
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Copyright (C) 2014-2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#ifndef __INTERNAL_SIGNALS_H
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# define __INTERNAL_SIGNALS_H
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#include <internal-sigset.h>
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#include <limits.h>
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#include <signal.h>
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#include <sigsetops.h>
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#include <stdbool.h>
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#include <stddef.h>
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#include <sysdep.h>
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/* The signal used for asynchronous cancelation. */
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#define SIGCANCEL __SIGRTMIN
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/* Signal needed for the kernel-supported POSIX timer implementation.
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We can reuse the cancellation signal since we can distinguish
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cancellation from timer expirations. */
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#define SIGTIMER SIGCANCEL
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/* Signal used to implement the setuid et.al. functions. */
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#define SIGSETXID (__SIGRTMIN + 1)
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/* How many signal numbers need to be reserved for libpthread's private uses
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(SIGCANCEL and SIGSETXID). */
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#define RESERVED_SIGRT 2
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/* Return is sig is used internally. */
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static inline bool
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is_internal_signal (int sig)
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{
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return (sig == SIGCANCEL) || (sig == SIGSETXID);
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}
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/* Remove internal glibc signal from the mask. */
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static inline void
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clear_internal_signals (sigset_t *set)
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{
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__sigdelset (set, SIGCANCEL);
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__sigdelset (set, SIGSETXID);
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}
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static const internal_sigset_t sigall_set = {
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.__val = {[0 ... __NSIG_WORDS-1 ] = -1 }
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};
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/* Obtain and change blocked signals, including internal glibc ones. */
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static inline int
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internal_sigprocmask (int how, const internal_sigset_t *set,
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internal_sigset_t *oldset)
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{
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return INTERNAL_SYSCALL_CALL (rt_sigprocmask, how, set, oldset,
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__NSIG_BYTES);
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}
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/* Block all signals, including internal glibc ones. */
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static inline void
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internal_signal_block_all (internal_sigset_t *oset)
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{
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INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_BLOCK, &sigall_set, oset,
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__NSIG_BYTES);
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}
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/* Restore current process signal mask. */
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static inline void
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internal_signal_restore_set (const internal_sigset_t *set)
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{
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INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_SETMASK, set, NULL,
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__NSIG_BYTES);
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}
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/* It is used on timer_create code directly on sigwaitinfo call, so it can not
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use the internal_sigset_t definitions. */
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static const sigset_t sigtimer_set = {
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.__val = { [0] = __sigmask (SIGTIMER),
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[1 ... _SIGSET_NWORDS-1] = 0
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}
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};
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/* Unblock only SIGTIMER. */
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static inline void
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signal_unblock_sigtimer (void)
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{
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INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_UNBLOCK, &sigtimer_set, NULL,
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__NSIG_BYTES);
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}
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#endif
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