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b6dec188 | 1 | /* Return backtrace of current program state. |
d4697bc9 | 2 | Copyright (C) 2008-2014 Free Software Foundation, Inc. |
b6dec188 MK |
3 | This file is part of the GNU C Library. |
4 | Contributed by Kazu Hirata <kazu@codesourcery.com>, 2008. | |
5 | ||
6 | The GNU C Library is free software; you can redistribute it and/or | |
7 | modify it under the terms of the GNU Lesser General Public | |
8 | License as published by the Free Software Foundation; either | |
9 | version 2.1 of the License, or (at your option) any later version. | |
10 | ||
11 | The GNU C Library is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | Lesser General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU Lesser General Public | |
ab84e3ff PE |
17 | License along with the GNU C Library. If not, see |
18 | <http://www.gnu.org/licenses/>. */ | |
b6dec188 MK |
19 | |
20 | #include <bits/libc-lock.h> | |
21 | #include <dlfcn.h> | |
22 | #include <execinfo.h> | |
23 | #include <stdlib.h> | |
24 | #include <unwind.h> | |
25 | ||
26 | struct trace_arg | |
27 | { | |
28 | void **array; | |
29 | int cnt, size; | |
30 | }; | |
31 | ||
32 | #ifdef SHARED | |
33 | static _Unwind_Reason_Code (*unwind_backtrace) (_Unwind_Trace_Fn, void *); | |
34 | static _Unwind_VRS_Result (*unwind_vrs_get) (_Unwind_Context *, | |
35 | _Unwind_VRS_RegClass, | |
36 | _uw, | |
37 | _Unwind_VRS_DataRepresentation, | |
38 | void *); | |
39 | ||
40 | static void *libgcc_handle; | |
41 | ||
42 | static void | |
43 | init (void) | |
44 | { | |
45 | libgcc_handle = __libc_dlopen ("libgcc_s.so.1"); | |
46 | ||
47 | if (libgcc_handle == NULL) | |
48 | return; | |
49 | ||
50 | unwind_backtrace = __libc_dlsym (libgcc_handle, "_Unwind_Backtrace"); | |
51 | unwind_vrs_get = __libc_dlsym (libgcc_handle, "_Unwind_VRS_Get"); | |
52 | if (unwind_vrs_get == NULL) | |
53 | unwind_backtrace = NULL; | |
54 | } | |
55 | ||
56 | /* This function is identical to "_Unwind_GetGR", except that it uses | |
57 | "unwind_vrs_get" instead of "_Unwind_VRS_Get". */ | |
58 | static inline _Unwind_Word | |
59 | unwind_getgr (_Unwind_Context *context, int regno) | |
60 | { | |
61 | _uw val; | |
62 | unwind_vrs_get (context, _UVRSC_CORE, regno, _UVRSD_UINT32, &val); | |
63 | return val; | |
64 | } | |
65 | ||
66 | /* This macro is identical to the _Unwind_GetIP macro, except that it | |
67 | uses "unwind_getgr" instead of "_Unwind_GetGR". */ | |
68 | # define unwind_getip(context) \ | |
69 | (unwind_getgr (context, 15) & ~(_Unwind_Word)1) | |
70 | #else | |
71 | # define unwind_backtrace _Unwind_Backtrace | |
72 | # define unwind_getip _Unwind_GetIP | |
73 | #endif | |
74 | ||
75 | static _Unwind_Reason_Code | |
76 | backtrace_helper (struct _Unwind_Context *ctx, void *a) | |
77 | { | |
78 | struct trace_arg *arg = a; | |
79 | ||
80 | /* We are first called with address in the __backtrace function. | |
81 | Skip it. */ | |
82 | if (arg->cnt != -1) | |
83 | arg->array[arg->cnt] = (void *) unwind_getip (ctx); | |
84 | if (++arg->cnt == arg->size) | |
85 | return _URC_END_OF_STACK; | |
86 | return _URC_NO_REASON; | |
87 | } | |
88 | ||
89 | int | |
90 | __backtrace (array, size) | |
91 | void **array; | |
92 | int size; | |
93 | { | |
94 | struct trace_arg arg = { .array = array, .size = size, .cnt = -1 }; | |
95 | #ifdef SHARED | |
96 | __libc_once_define (static, once); | |
97 | ||
98 | __libc_once (once, init); | |
99 | if (unwind_backtrace == NULL) | |
100 | return 0; | |
101 | #endif | |
102 | ||
103 | if (size >= 1) | |
104 | unwind_backtrace (backtrace_helper, &arg); | |
105 | ||
106 | if (arg.cnt > 1 && arg.array[arg.cnt - 1] == NULL) | |
107 | --arg.cnt; | |
108 | return arg.cnt != -1 ? arg.cnt : 0; | |
109 | } | |
110 | weak_alias (__backtrace, backtrace) | |
111 | libc_hidden_def (__backtrace) | |
112 | ||
113 | ||
114 | #ifdef SHARED | |
115 | /* Free all resources if necessary. */ | |
116 | libc_freeres_fn (free_mem) | |
117 | { | |
118 | unwind_backtrace = NULL; | |
119 | if (libgcc_handle != NULL) | |
120 | { | |
121 | __libc_dlclose (libgcc_handle); | |
122 | libgcc_handle = NULL; | |
123 | } | |
124 | } | |
125 | #endif |