1 //===-- sanitizer_symbolizer_libbacktrace.cpp -----------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file is shared between AddressSanitizer and ThreadSanitizer
10 // run-time libraries.
11 // Libbacktrace implementation of symbolizer parts.
12 //===----------------------------------------------------------------------===//
13 
14 #include "sanitizer_symbolizer_libbacktrace.h"
15 
16 #include "sanitizer_internal_defs.h"
17 #include "sanitizer_platform.h"
18 #include "sanitizer_symbolizer.h"
19 
20 #if SANITIZER_LIBBACKTRACE
21 # include "backtrace-supported.h"
22 # if SANITIZER_POSIX && BACKTRACE_SUPPORTED && !BACKTRACE_USES_MALLOC
23 #  include "backtrace.h"
24 #  if SANITIZER_CP_DEMANGLE
25 #   undef ARRAY_SIZE
26 #   include "demangle.h"
27 #  endif
28 # else
29 #  define SANITIZER_LIBBACKTRACE 0
30 # endif
31 #endif
32 
33 namespace __sanitizer {
34 
35 static char *DemangleAlloc(const char *name, bool always_alloc);
36 
37 #if SANITIZER_LIBBACKTRACE
38 
39 namespace {
40 
41 # if SANITIZER_CP_DEMANGLE
42 struct CplusV3DemangleData {
43   char *buf;
44   uptr size, allocated;
45 };
46 
47 extern "C" {
48 static void CplusV3DemangleCallback(const char *s, size_t l, void *vdata) {
49   CplusV3DemangleData *data = (CplusV3DemangleData *)vdata;
50   uptr needed = data->size + l + 1;
51   if (needed > data->allocated) {
52     data->allocated *= 2;
53     if (needed > data->allocated)
54       data->allocated = needed;
55     char *buf = (char *)InternalAlloc(data->allocated);
56     if (data->buf) {
57       internal_memcpy(buf, data->buf, data->size);
58       InternalFree(data->buf);
59     }
60     data->buf = buf;
61   }
62   internal_memcpy(data->buf + data->size, s, l);
63   data->buf[data->size + l] = '\0';
64   data->size += l;
65 }
66 }  // extern "C"
67 
68 char *CplusV3Demangle(const char *name) {
69   CplusV3DemangleData data;
70   data.buf = 0;
71   data.size = 0;
72   data.allocated = 0;
73   if (cplus_demangle_v3_callback(name, DMGL_PARAMS | DMGL_ANSI,
74                                  CplusV3DemangleCallback, &data)) {
75     if (data.size + 64 > data.allocated)
76       return data.buf;
77     char *buf = internal_strdup(data.buf);
78     InternalFree(data.buf);
79     return buf;
80   }
81   if (data.buf)
82     InternalFree(data.buf);
83   return 0;
84 }
85 # endif  // SANITIZER_CP_DEMANGLE
86 
87 struct SymbolizeCodeCallbackArg {
88   SymbolizedStack *first;
89   SymbolizedStack *last;
90   uptr frames_symbolized;
91 
92   AddressInfo *get_new_frame(uintptr_t addr) {
93     CHECK(last);
94     if (frames_symbolized > 0) {
95       SymbolizedStack *cur = SymbolizedStack::New(addr);
96       AddressInfo *info = &cur->info;
97       info->FillModuleInfo(first->info.module, first->info.module_offset,
98                            first->info.module_arch);
99       last->next = cur;
100       last = cur;
101     }
102     CHECK_EQ(addr, first->info.address);
103     CHECK_EQ(addr, last->info.address);
104     return &last->info;
105   }
106 };
107 
108 extern "C" {
109 static int SymbolizeCodePCInfoCallback(void *vdata, uintptr_t addr,
110                                        const char *filename, int lineno,
111                                        const char *function) {
112   SymbolizeCodeCallbackArg *cdata = (SymbolizeCodeCallbackArg *)vdata;
113   if (function) {
114     AddressInfo *info = cdata->get_new_frame(addr);
115     info->function = DemangleAlloc(function, /*always_alloc*/ true);
116     if (filename)
117       info->file = internal_strdup(filename);
118     info->line = lineno;
119     cdata->frames_symbolized++;
120   }
121   return 0;
122 }
123 
124 static void SymbolizeCodeCallback(void *vdata, uintptr_t addr,
125                                   const char *symname, uintptr_t, uintptr_t) {
126   SymbolizeCodeCallbackArg *cdata = (SymbolizeCodeCallbackArg *)vdata;
127   if (symname) {
128     AddressInfo *info = cdata->get_new_frame(addr);
129     info->function = DemangleAlloc(symname, /*always_alloc*/ true);
130     cdata->frames_symbolized++;
131   }
132 }
133 
134 static void SymbolizeDataCallback(void *vdata, uintptr_t, const char *symname,
135                                   uintptr_t symval, uintptr_t symsize) {
136   DataInfo *info = (DataInfo *)vdata;
137   if (symname && symval) {
138     info->name = DemangleAlloc(symname, /*always_alloc*/ true);
139     info->start = symval;
140     info->size = symsize;
141   }
142 }
143 
144 static void ErrorCallback(void *, const char *, int) {}
145 }  // extern "C"
146 
147 }  // namespace
148 
149 LibbacktraceSymbolizer *LibbacktraceSymbolizer::get(LowLevelAllocator *alloc) {
150   // State created in backtrace_create_state is leaked.
151   void *state = (void *)(backtrace_create_state("/proc/self/exe", 0,
152                                                 ErrorCallback, NULL));
153   if (!state)
154     return 0;
155   return new(*alloc) LibbacktraceSymbolizer(state);
156 }
157 
158 bool LibbacktraceSymbolizer::SymbolizePC(uptr addr, SymbolizedStack *stack) {
159   SymbolizeCodeCallbackArg data;
160   data.first = stack;
161   data.last = stack;
162   data.frames_symbolized = 0;
163   backtrace_pcinfo((backtrace_state *)state_, addr, SymbolizeCodePCInfoCallback,
164                    ErrorCallback, &data);
165   if (data.frames_symbolized > 0)
166     return true;
167   backtrace_syminfo((backtrace_state *)state_, addr, SymbolizeCodeCallback,
168                     ErrorCallback, &data);
169   return (data.frames_symbolized > 0);
170 }
171 
172 bool LibbacktraceSymbolizer::SymbolizeData(uptr addr, DataInfo *info) {
173   backtrace_syminfo((backtrace_state *)state_, addr, SymbolizeDataCallback,
174                     ErrorCallback, info);
175   return true;
176 }
177 
178 #else  // SANITIZER_LIBBACKTRACE
179 
180 LibbacktraceSymbolizer *LibbacktraceSymbolizer::get(LowLevelAllocator *alloc) {
181   return 0;
182 }
183 
184 bool LibbacktraceSymbolizer::SymbolizePC(uptr addr, SymbolizedStack *stack) {
185   (void)state_;
186   return false;
187 }
188 
189 bool LibbacktraceSymbolizer::SymbolizeData(uptr addr, DataInfo *info) {
190   return false;
191 }
192 
193 #endif  // SANITIZER_LIBBACKTRACE
194 
195 static char *DemangleAlloc(const char *name, bool always_alloc) {
196 #if SANITIZER_LIBBACKTRACE && SANITIZER_CP_DEMANGLE
197   if (char *demangled = CplusV3Demangle(name))
198     return demangled;
199 #endif
200   if (always_alloc)
201     return internal_strdup(name);
202   return nullptr;
203 }
204 
205 const char *LibbacktraceSymbolizer::Demangle(const char *name) {
206   return DemangleAlloc(name, /*always_alloc*/ false);
207 }
208 
209 }  // namespace __sanitizer
210