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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>
124 lines
3.4 KiB
C
124 lines
3.4 KiB
C
/* Copyright (C) 1991-2022 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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#include <libc-lock.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <internal-signals.h>
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/* Try to get a machine dependent instruction which will make the
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program crash. This is used in case everything else fails. */
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#include <abort-instr.h>
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#ifndef ABORT_INSTRUCTION
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/* No such instruction is available. */
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# define ABORT_INSTRUCTION
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#endif
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/* Exported variable to locate abort message in core files etc. */
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struct abort_msg_s *__abort_msg;
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libc_hidden_def (__abort_msg)
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/* We must avoid to run in circles. Therefore we remember how far we
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already got. */
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static int stage;
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/* We should be prepared for multiple threads trying to run abort. */
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__libc_lock_define_initialized_recursive (static, lock);
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/* Cause an abnormal program termination with core-dump. */
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void
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abort (void)
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{
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struct sigaction act;
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/* First acquire the lock. */
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__libc_lock_lock_recursive (lock);
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/* Now it's for sure we are alone. But recursive calls are possible. */
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/* Unblock SIGABRT. */
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if (stage == 0)
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{
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++stage;
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internal_sigset_t sigs;
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internal_sigemptyset (&sigs);
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internal_sigaddset (&sigs, SIGABRT);
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internal_sigprocmask (SIG_UNBLOCK, &sigs, NULL);
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}
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/* Send signal which possibly calls a user handler. */
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if (stage == 1)
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{
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/* This stage is special: we must allow repeated calls of
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`abort' when a user defined handler for SIGABRT is installed.
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This is risky since the `raise' implementation might also
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fail but I don't see another possibility. */
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int save_stage = stage;
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stage = 0;
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__libc_lock_unlock_recursive (lock);
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raise (SIGABRT);
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__libc_lock_lock_recursive (lock);
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stage = save_stage + 1;
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}
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/* There was a handler installed. Now remove it. */
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if (stage == 2)
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{
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++stage;
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memset (&act, '\0', sizeof (struct sigaction));
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act.sa_handler = SIG_DFL;
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__sigfillset (&act.sa_mask);
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act.sa_flags = 0;
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__sigaction (SIGABRT, &act, NULL);
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}
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/* Try again. */
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if (stage == 3)
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{
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++stage;
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raise (SIGABRT);
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}
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/* Now try to abort using the system specific command. */
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if (stage == 4)
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{
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++stage;
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ABORT_INSTRUCTION;
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}
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/* If we can't signal ourselves and the abort instruction failed, exit. */
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if (stage == 5)
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{
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++stage;
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_exit (127);
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}
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/* If even this fails try to use the provided instruction to crash
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or otherwise make sure we never return. */
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while (1)
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/* Try for ever and ever. */
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ABORT_INSTRUCTION;
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}
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libc_hidden_def (abort)
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