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      1 /*	$OpenBSD: abort.c,v 1.14 2005/08/08 08:05:36 espie Exp $ */
      2 /*
      3  * Copyright (c) 1985 Regents of the University of California.
      4  * All rights reserved.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  * 1. Redistributions of source code must retain the above copyright
     10  *    notice, this list of conditions and the following disclaimer.
     11  * 2. Redistributions in binary form must reproduce the above copyright
     12  *    notice, this list of conditions and the following disclaimer in the
     13  *    documentation and/or other materials provided with the distribution.
     14  * 3. Neither the name of the University nor the names of its contributors
     15  *    may be used to endorse or promote products derived from this software
     16  *    without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     28  * SUCH DAMAGE.
     29  */
     30 
     31 #include <signal.h>
     32 #include <stdlib.h>
     33 #include <unistd.h>
     34 #include "thread_private.h"
     35 #include "atexit.h"
     36 
     37 /* temporary, for bug hunting */
     38 #include "logd.h"
     39 #define debug_log(format, ...)  \
     40     __libc_android_log_print(ANDROID_LOG_DEBUG, "libc-abort", (format), ##__VA_ARGS__ )
     41 
     42 #ifdef __arm__
     43 __LIBC_HIDDEN__ void
     44 __libc_android_abort(void)
     45 #else
     46 void
     47 abort(void)
     48 #endif
     49 {
     50 	struct atexit *p = __atexit;
     51 	static int cleanup_called = 0;
     52 	sigset_t mask;
     53 
     54 
     55 	sigfillset(&mask);
     56 	/*
     57 	 * don't block SIGABRT to give any handler a chance; we ignore
     58 	 * any errors -- X311J doesn't allow abort to return anyway.
     59 	 */
     60 	sigdelset(&mask, SIGABRT);
     61     /* temporary, so deliberate seg fault can be caught by debuggerd */
     62 	sigdelset(&mask, SIGSEGV);
     63     /* -- */
     64 	(void)sigprocmask(SIG_SETMASK, &mask, (sigset_t *)NULL);
     65 
     66 	/*
     67 	 * POSIX requires we flush stdio buffers on abort
     68 	 */
     69 	if (cleanup_called == 0) {
     70 		while (p != NULL && p->next != NULL)
     71 			p = p->next;
     72 		/* the check for fn_dso == NULL is mostly paranoia */
     73 		if (p != NULL && p->fns[0].fn_dso == NULL &&
     74 		    p->fns[0].fn_ptr.std_func != NULL) {
     75 			cleanup_called = 1;
     76 			(*p->fns[0].fn_ptr.std_func)();
     77 		}
     78 	}
     79 
     80     /* temporary, for bug hunting */
     81     /* seg fault seems to produce better debuggerd results than SIGABRT */
     82     *((char*)0xdeadbaad) = 39;
     83     /* -- */
     84 
     85 	(void)kill(getpid(), SIGABRT);
     86 
     87 	/*
     88 	 * if SIGABRT ignored, or caught and the handler returns, do
     89 	 * it again, only harder.
     90 	 */
     91         {
     92             struct sigaction sa;
     93 
     94             sa.sa_handler = SIG_DFL;
     95             sa.sa_flags   = SA_RESTART;
     96             sigemptyset(&sa.sa_mask);
     97 
     98             (void)sigaction( SIGABRT, &sa, &sa );
     99         }
    100 
    101 	(void)sigprocmask(SIG_SETMASK, &mask, (sigset_t *)NULL);
    102 	(void)kill(getpid(), SIGABRT);
    103 	_exit(1);
    104 }
    105 
    106 #ifdef __arm__
    107 /*
    108  * abort() does not return, which gcc interprets to mean that it doesn't
    109  * need to preserve any of the callee-save registers.  Unfortunately this
    110  * includes the link register, so if LR is used there is no way to determine
    111  * which function called abort().
    112  *
    113  * We work around this by inserting a trivial stub that doesn't alter
    114  * any of the "interesting" registers and thus doesn't need to save them.
    115  * We can't just call __libc_android_abort from C because gcc uses "bl"
    116  * without first saving LR, so we use an asm statement.  This also has
    117  * the side-effect of replacing abort() with __libc_android_abort() in
    118  * the stack trace.
    119  *
    120  * Ideally __libc_android_abort would be static, but I haven't figured out
    121  * how to tell gcc to call a static function from an asm statement.
    122  */
    123 void
    124 abort(void)
    125 {
    126     asm ("b __libc_android_abort");
    127     _exit(1);       /* suppress gcc noreturn warnings */
    128 }
    129 #endif
    130 
    131