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 38 struct tracer_context { 39 void **arr; 40 size_t len; 41 size_t n; 42 }; 43 44 static _Unwind_Reason_Code 45 tracer(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 58 size_t 59 backtrace(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