1 /* $NetBSD: unwind.c,v 1.3 2019/01/30 22:46:49 mrg 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 "execinfo.h"
36
37 struct tracer_context {
38 void **arr;
39 size_t len;
40 size_t n;
41 };
42
43 typedef enum {
44 _URC_NO_REASON = 0,
45 #if defined(__arm__) && !defined(__USING_SJLJ_EXCEPTIONS__) && \
46 !defined(__ARM_DWARF_EH__) && !defined(__SEH__)
47 _URC_OK = 0, /* used by ARM EHABI */
48 #endif
49 _URC_FOREIGN_EXCEPTION_CAUGHT = 1,
50
51 _URC_FATAL_PHASE2_ERROR = 2,
52 _URC_FATAL_PHASE1_ERROR = 3,
53 _URC_NORMAL_STOP = 4,
54
55 _URC_END_OF_STACK = 5,
56 _URC_HANDLER_FOUND = 6,
57 _URC_INSTALL_CONTEXT = 7,
58 _URC_CONTINUE_UNWIND = 8,
59 #if defined(__arm__) && !defined(__USING_SJLJ_EXCEPTIONS__) && \
60 !defined(__ARM_DWARF_EH__) && !defined(__SEH__)
61 _URC_FAILURE = 9 /* used by ARM EHABI */
62 #endif
63 } _Unwind_Reason_Code;
64
65 struct _Unwind_Context;
66 typedef unsigned int _Unwind_Word __attribute__((__mode__(__unwind_word__)));
67
68 _Unwind_Word _Unwind_GetGR(struct _Unwind_Context *, int);
69 _Unwind_Word _Unwind_GetIP(struct _Unwind_Context *);
70 typedef _Unwind_Reason_Code (*_Unwind_Trace_Fn)(struct _Unwind_Context *,
71 void *);
72 extern _Unwind_Reason_Code _Unwind_Backtrace (_Unwind_Trace_Fn, void *);
73 static _Unwind_Reason_Code
tracer(struct _Unwind_Context * ctx,void * arg)74 tracer(struct _Unwind_Context *ctx, void *arg)
75 {
76 struct tracer_context *t = arg;
77 if (t->n == (size_t)~0) {
78 /* Skip backtrace frame */
79 t->n = 0;
80 return 0;
81 }
82 if (t->n < t->len)
83 t->arr[t->n++] = (void *)_Unwind_GetIP(ctx);
84 else
85 return _URC_END_OF_STACK;
86 return _URC_NO_REASON;
87 }
88
89 size_t
backtrace(void ** arr,size_t len)90 backtrace(void **arr, size_t len)
91 {
92 struct tracer_context ctx;
93
94 ctx.arr = arr;
95 ctx.len = len;
96 ctx.n = (size_t)~0;
97
98 _Unwind_Backtrace(tracer, &ctx);
99 if (ctx.n == (size_t)~0)
100 ctx.n = 0;
101
102 return ctx.n;
103 }
104