uclibc-ng/libc/stdlib/abort.c

/* Copyright (C) 1991 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA.  */

/* Hacked up for uClibc by Erik Andersen */

#include <features.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <errno.h>



/* Defeat compiler optimization which assumes function addresses are never NULL */
static __always_inline int not_null_ptr(const void *p)
{
	const void *q;
	__asm__ (""
		: "=r" (q) /* output */
		: "0" (p) /* input */
	);
	return q != 0;
}

/* Our last ditch effort to commit suicide */
#ifdef __UCLIBC_ABORT_INSTRUCTION__
# define ABORT_INSTRUCTION __asm__(__UCLIBC_ABORT_INSTRUCTION__)
#else
# define ABORT_INSTRUCTION
# warning "no abort instruction defined for your arch"
#endif

static smallint been_there_done_that = 0;

/* Be prepared in case multiple threads try to abort() */
#include <bits/uClibc_mutex.h>
__UCLIBC_MUTEX_STATIC(mylock, PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP);

/* Cause an abnormal program termination with core-dump */
void abort(void)
{
	sigset_t sigs;

	/* Make sure we acquire the lock before proceeding */
	__UCLIBC_MUTEX_LOCK_CANCEL_UNSAFE(mylock);

	/* Unmask SIGABRT to be sure we can get it */
	__sigemptyset(&sigs);
	__sigaddset(&sigs, SIGABRT);
	sigprocmask(SIG_UNBLOCK, &sigs, NULL);

	while (1) {
		/* Try to suicide with a SIGABRT */
		if (been_there_done_that == 0) {
			been_there_done_that++;

#ifdef __UCLIBC_HAS_STDIO_SHUTDOWN_ON_ABORT__
			/* If we are using stdio, try to shut it down.  At the very least,
			 * this will attempt to commit all buffered writes.  It may also
			 * unbuffer all writable files, or close them outright.
			 * Check the stdio routines for details. */
			if (not_null_ptr(_stdio_term)) {
				_stdio_term();
			}
#endif

abort_it:
			__UCLIBC_MUTEX_UNLOCK_CANCEL_UNSAFE(mylock);
			raise(SIGABRT);
			__UCLIBC_MUTEX_LOCK_CANCEL_UNSAFE(mylock);
		}

		/* Still here?  Try to remove any signal handlers */
		if (been_there_done_that == 1) {
			struct sigaction act;

			been_there_done_that++;
			memset(&act, '\0', sizeof(struct sigaction));
			if (SIG_DFL) /* if it's constant zero, already done */
				act.sa_handler = SIG_DFL;
			__sigfillset(&act.sa_mask);
			sigaction(SIGABRT, &act, NULL);

			goto abort_it;
		}

		/* Still here?  Try to suicide with an illegal instruction */
		if (been_there_done_that == 2) {
			been_there_done_that++;
			ABORT_INSTRUCTION;
		}

		/* Still here?  Try to at least exit */
		if (been_there_done_that == 3) {
			been_there_done_that++;
			_exit(127);
		}

		/* Still here?  We're screwed.  Sleepy time.  Good night. */
		while (1)
			/* Try for ever and ever */
			ABORT_INSTRUCTION;
	}
}
libc_hidden_def(abort)