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unwind/debug.c
1
21#ifndef _GNU_SOURCE
22#define _GNU_SOURCE // NOLINT(bugprone-reserved-identifier,cert-dcl37-c,cert-dcl51-cpp)
23#endif
24
25#include <assert.h>
26#include <stdlib.h>
27#include <unwind.h>
28
29#include <winpr/string.h>
30#include "debug.h"
31
32#include <winpr/wlog.h>
33#include "../log.h"
34
35#include <dlfcn.h>
36
37#define TAG WINPR_TAG("utils.unwind")
38
39#define UNWIND_MAX_LINE_SIZE 1024ULL
40
41typedef struct
42{
43 union
44 {
45 uintptr_t uw;
46 void* pv;
47 } pc;
48 union
49 {
50 uintptr_t uptr;
51 void* pv;
52 } langSpecificData;
53} unwind_info_t;
54
55typedef struct
56{
57 size_t pos;
58 size_t size;
59 unwind_info_t* info;
60} unwind_context_t;
61
62static const char* unwind_reason_str(_Unwind_Reason_Code code)
63{
64 switch (code)
65 {
66#if defined(__arm__) && !defined(__USING_SJLJ_EXCEPTIONS__) && !defined(__ARM_DWARF_EH__) && \
67 !defined(__SEH__)
68 case _URC_OK:
69 return "_URC_OK";
70#else
71 case _URC_NO_REASON:
72 return "_URC_NO_REASON";
73 case _URC_FATAL_PHASE2_ERROR:
74 return "_URC_FATAL_PHASE2_ERROR";
75 case _URC_FATAL_PHASE1_ERROR:
76 return "_URC_FATAL_PHASE1_ERROR";
77 case _URC_NORMAL_STOP:
78 return "_URC_NORMAL_STOP";
79#endif
80 case _URC_FOREIGN_EXCEPTION_CAUGHT:
81 return "_URC_FOREIGN_EXCEPTION_CAUGHT";
82 case _URC_END_OF_STACK:
83 return "_URC_END_OF_STACK";
84 case _URC_HANDLER_FOUND:
85 return "_URC_HANDLER_FOUND";
86 case _URC_INSTALL_CONTEXT:
87 return "_URC_INSTALL_CONTEXT";
88 case _URC_CONTINUE_UNWIND:
89 return "_URC_CONTINUE_UNWIND";
90#if defined(__arm__) && !defined(__USING_SJLJ_EXCEPTIONS__) && !defined(__ARM_DWARF_EH__) && \
91 !defined(__SEH__)
92 case _URC_FAILURE:
93 return "_URC_FAILURE";
94#endif
95 default:
96 return "_URC_UNKNOWN";
97 }
98}
99
100static const char* unwind_reason_str_buffer(_Unwind_Reason_Code code, char* buffer, size_t size)
101{
102 const char* str = unwind_reason_str(code);
103 (void)_snprintf(buffer, size, "%s [0x%02x]", str, code);
104 return buffer;
105}
106
107static _Unwind_Reason_Code unwind_backtrace_callback(struct _Unwind_Context* context, void* arg)
108{
109 unwind_context_t* ctx = arg;
110
111 assert(ctx);
112
113 if (ctx->pos < ctx->size)
114 {
115 unwind_info_t* info = &ctx->info[ctx->pos++];
116 info->pc.uw = _Unwind_GetIP(context);
117
118 /* _Unwind_GetLanguageSpecificData has various return value definitions,
119 * cast to the type we expect and disable linter warnings
120 */
121 // NOLINTNEXTLINE(google-readability-casting,readability-redundant-casting)
122 info->langSpecificData.pv = (void*)_Unwind_GetLanguageSpecificData(context);
123 }
124
125 return _URC_NO_REASON;
126}
127
128void* winpr_unwind_backtrace(DWORD size)
129{
130 _Unwind_Reason_Code rc = _URC_FOREIGN_EXCEPTION_CAUGHT;
131 unwind_context_t* ctx = calloc(1, sizeof(unwind_context_t));
132 if (!ctx)
133 goto fail;
134 ctx->size = size;
135 ctx->info = calloc(size, sizeof(unwind_info_t));
136 if (!ctx->info)
137 goto fail;
138
139 rc = _Unwind_Backtrace(unwind_backtrace_callback, ctx);
140 if (rc != _URC_END_OF_STACK)
141 {
142 char buffer[64] = { 0 };
143 WLog_ERR(TAG, "_Unwind_Backtrace failed with %s",
144 unwind_reason_str_buffer(rc, buffer, sizeof(buffer)));
145 goto fail;
146 }
147
148 return ctx;
149fail:
150 winpr_unwind_backtrace_free(ctx);
151 return NULL;
152}
153
154void winpr_unwind_backtrace_free(void* buffer)
155{
156 unwind_context_t* ctx = buffer;
157 if (!ctx)
158 return;
159 free(ctx->info);
160 free(ctx);
161}
162
163char** winpr_unwind_backtrace_symbols(void* buffer, size_t* used)
164{
165 union
166 {
167 void* pv;
168 char* cp;
169 char** cpp;
170 } cnv;
171 unwind_context_t* ctx = buffer;
172 cnv.cpp = NULL;
173
174 if (!ctx)
175 return NULL;
176
177 cnv.pv = calloc(ctx->pos * (sizeof(char*) + UNWIND_MAX_LINE_SIZE), sizeof(char*));
178 if (!cnv.pv)
179 return NULL;
180
181 if (used)
182 *used = ctx->pos;
183
184 for (size_t x = 0; x < ctx->pos; x++)
185 {
186 char* msg = cnv.cp + ctx->pos * sizeof(char*) + x * UNWIND_MAX_LINE_SIZE;
187 const unwind_info_t* info = &ctx->info[x];
188 Dl_info dlinfo = { 0 };
189 int rc = dladdr(info->pc.pv, &dlinfo);
190
191 cnv.cpp[x] = msg;
192
193 if (rc == 0)
194 (void)_snprintf(msg, UNWIND_MAX_LINE_SIZE, "unresolvable, address=%p", info->pc.pv);
195 else
196 (void)_snprintf(msg, UNWIND_MAX_LINE_SIZE, "dli_fname=%s [%p], dli_sname=%s [%p]",
197 dlinfo.dli_fname, dlinfo.dli_fbase, dlinfo.dli_sname, dlinfo.dli_saddr);
198 }
199
200 // NOLINTNEXTLINE(clang-analyzer-unix.Malloc): function is an allocator
201 return cnv.cpp;
202}