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      1 /*	$NetBSD: builtin.c,v 1.1 2012/05/26 22:02:29 christos Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2012 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Christos Zoulas.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 #include <sys/cdefs.h>
     32 __RCSID("$NetBSD: builtin.c,v 1.1 2012/05/26 22:02:29 christos Exp $");
     33 
     34 #include <sys/param.h>
     35 #include <sys/types.h>
     36 
     37 #include "execinfo.h"
     38 
     39 #ifdef __MACHINE_STACK_GROWS_UP
     40 #define BELOW >
     41 #else
     42 #define BELOW <
     43 #endif
     44 
     45 #ifdef __lint__
     46 #define __builtin_frame_address(a)	((void *)a)
     47 #endif
     48 
     49 struct frameinfo {
     50 	struct frameinfo *next;
     51 	void *return_address;
     52 };
     53 
     54 size_t
     55 backtrace(void **trace, size_t len)
     56 {
     57 	const struct frameinfo *frame = __builtin_frame_address(0);
     58 	void *stack = &stack;
     59 
     60 	for (size_t i = 0; i < len; i++) {
     61 		if ((const void *)frame BELOW stack)
     62 			return i;
     63 		trace[i] = frame->return_address;
     64 		frame = frame->next;
     65 	}
     66 
     67 	return len;
     68 }
     69