The code generated for Thumb and Thumb2 targets has different handling for abort(). Because abort() is "noreturn", it doesn't need to preserve the callee-save registers. The Thumb2 version trashes LR and makes it impossible to figure out who called abort(). This inserts a trivial stub function; net effect is stack traces are reasonable after an abort(). For bug 2191452.
		
			
				
	
	
		
			131 lines
		
	
	
		
			4.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			131 lines
		
	
	
		
			4.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*	$OpenBSD: abort.c,v 1.14 2005/08/08 08:05:36 espie Exp $ */
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/*
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 * Copyright (c) 1985 Regents of the University of California.
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 * 3. Neither the name of the University nor the names of its contributors
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 *    may be used to endorse or promote products derived from this software
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 *    without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 * SUCH DAMAGE.
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 */
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#include <signal.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include "thread_private.h"
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#include "atexit.h"
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/* temporary, for bug hunting */
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#include "logd.h"
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#define debug_log(format, ...)  \
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    __libc_android_log_print(ANDROID_LOG_DEBUG, "libc-abort", (format), ##__VA_ARGS__ )
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#ifdef __arm__
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void
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__libc_android_abort(void)
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#else
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void
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abort(void)
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#endif
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{
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	struct atexit *p = __atexit;
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	static int cleanup_called = 0;
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	sigset_t mask;
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	sigfillset(&mask);
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	/*
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	 * don't block SIGABRT to give any handler a chance; we ignore
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	 * any errors -- X311J doesn't allow abort to return anyway.
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	 */
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	sigdelset(&mask, SIGABRT);
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    /* temporary, so deliberate seg fault can be caught by debuggerd */
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	sigdelset(&mask, SIGSEGV);
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    /* -- */
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	(void)sigprocmask(SIG_SETMASK, &mask, (sigset_t *)NULL);
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	/*
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	 * POSIX requires we flush stdio buffers on abort
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	 */
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	if (cleanup_called == 0) {
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		while (p != NULL && p->next != NULL)
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			p = p->next;
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		/* the check for fn_dso == NULL is mostly paranoia */
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		if (p != NULL && p->fns[0].fn_dso == NULL &&
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		    p->fns[0].fn_ptr.std_func != NULL) {
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			cleanup_called = 1;
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			(*p->fns[0].fn_ptr.std_func)();
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		}
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	}
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    /* temporary, for bug hunting */
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    /* seg fault seems to produce better debuggerd results than SIGABRT */
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    *((char*)0xdeadbaad) = 39;
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    /* -- */
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	(void)kill(getpid(), SIGABRT);
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	/*
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	 * if SIGABRT ignored, or caught and the handler returns, do
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	 * it again, only harder.
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	 */
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        {
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            struct sigaction sa;
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            sa.sa_handler = SIG_DFL;
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            sa.sa_flags   = SA_RESTART;
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            sigemptyset(&sa.sa_mask);
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            (void)sigaction( SIGABRT, &sa, &sa );
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        }
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	(void)sigprocmask(SIG_SETMASK, &mask, (sigset_t *)NULL);
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	(void)kill(getpid(), SIGABRT);
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	_exit(1);
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}
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#ifdef __arm__
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/*
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 * abort() does not return, which gcc interprets to mean that it doesn't
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 * need to preserve any of the callee-save registers.  Unfortunately this
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 * includes the link register, so if LR is used there is no way to determine
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 * which function called abort().
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 *
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 * We work around this by inserting a trivial stub that doesn't alter
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 * any of the "interesting" registers and thus doesn't need to save them.
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 * We can't just call __libc_android_abort from C because gcc uses "bl"
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 * without first saving LR, so we use an asm statement.  This also has
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 * the side-effect of replacing abort() with __libc_android_abort() in
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 * the stack trace.
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 *
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 * Ideally __libc_android_abort would be static, but I haven't figured out
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 * how to tell gcc to call a static function from an asm statement.
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 */
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void
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abort(void)
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{
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    asm ("b __libc_android_abort");
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    _exit(1);       /* suppress gcc noreturn warnings */
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}
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#endif
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