1/*	$NetBSD: unwind.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#include <sys/types.h>
33#include <stdio.h>
34
35#include "unwind.h"
36#include "execinfo.h"
37
38struct tracer_context {
39	void **arr;
40	size_t len;
41	size_t n;
42};
43
44static _Unwind_Reason_Code
45tracer(struct _Unwind_Context *ctx, void *arg)
46{
47	struct tracer_context *t = arg;
48	if (t->n == (size_t)~0) {
49		/* Skip backtrace frame */
50		t->n = 0;
51		return 0;
52	}
53	if (t->n < t->len)
54		t->arr[t->n++] = _Unwind_GetIP(ctx);
55	return 0;
56}
57
58size_t
59backtrace(void **arr, size_t len)
60{
61	struct tracer_context ctx;
62
63	ctx.arr = arr;
64	ctx.len = len;
65	ctx.n = (size_t)~0;
66
67	_Unwind_Backtrace(tracer, &ctx);
68	if (ctx.n != (size_t)~0 && ctx.n > 0)
69		ctx.arr[--ctx.n] = NULL;	/* Skip frame below __start */
70
71	return ctx.n;
72}
73