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/* Copyright (C) 1991-2017 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
<http://www.gnu.org/licenses/>. */
#include <libc-lock.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
/* Try to get a machine dependent instruction which will make the
program crash. This is used in case everything else fails. */
#include <abort-instr.h>
#ifndef ABORT_INSTRUCTION
/* No such instruction is available. */
# define ABORT_INSTRUCTION
#endif
#include <libio/libioP.h>
#define fflush(s) _IO_flush_all_lockp (0)
/* Exported variable to locate abort message in core files etc. */
struct abort_msg_s *__abort_msg __attribute__ ((nocommon));
libc_hidden_def (__abort_msg)
/* We must avoid to run in circles. Therefore we remember how far we
already got. */
static int stage;
/* We should be prepared for multiple threads trying to run abort. */
__libc_lock_define_initialized_recursive (static, lock);
/* Cause an abnormal program termination with core-dump. */
void
abort (void)
{
struct sigaction act;
sigset_t sigs;
/* First acquire the lock. */
__libc_lock_lock_recursive (lock);
/* Now it's for sure we are alone. But recursive calls are possible. */
/* Unlock SIGABRT. */
if (stage == 0)
{
++stage;
if (__sigemptyset (&sigs) == 0 &&
__sigaddset (&sigs, SIGABRT) == 0)
__sigprocmask (SIG_UNBLOCK, &sigs, (sigset_t *) NULL);
}
/* Flush all streams. We cannot close them now because the user
might have registered a handler for SIGABRT. */
if (stage == 1)
{
++stage;
fflush (NULL);
}
/* Send signal which possibly calls a user handler. */
if (stage == 2)
{
/* This stage is special: we must allow repeated calls of
`abort' when a user defined handler for SIGABRT is installed.
This is risky since the `raise' implementation might also
fail but I don't see another possibility. */
int save_stage = stage;
stage = 0;
__libc_lock_unlock_recursive (lock);
raise (SIGABRT);
__libc_lock_lock_recursive (lock);
stage = save_stage + 1;
}
/* There was a handler installed. Now remove it. */
if (stage == 3)
{
++stage;
memset (&act, '\0', sizeof (struct sigaction));
act.sa_handler = SIG_DFL;
__sigfillset (&act.sa_mask);
act.sa_flags = 0;
__sigaction (SIGABRT, &act, NULL);
}
/* Now close the streams which also flushes the output the user
defined handler might has produced. */
if (stage == 4)
{
++stage;
__fcloseall ();
}
/* Try again. */
if (stage == 5)
{
++stage;
raise (SIGABRT);
}
/* Now try to abort using the system specific command. */
if (stage == 6)
{
++stage;
ABORT_INSTRUCTION;
}
/* If we can't signal ourselves and the abort instruction failed, exit. */
if (stage == 7)
{
++stage;
_exit (127);
}
/* If even this fails try to use the provided instruction to crash
or otherwise make sure we never return. */
while (1)
/* Try for ever and ever. */
ABORT_INSTRUCTION;
}
libc_hidden_def (abort)
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