1 /* 2 * Copyright (C) 2013 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef _BACKTRACE_BACKTRACE_H 18 #define _BACKTRACE_BACKTRACE_H 19 20 #include <inttypes.h> 21 #include <stdint.h> 22 23 #include <string> 24 #include <vector> 25 26 #include <backtrace/backtrace_constants.h> 27 #include <backtrace/BacktraceMap.h> 28 29 #if defined(__LP64__) 30 #define PRIPTR "016" PRIx64 31 typedef uint64_t word_t; 32 #else 33 #define PRIPTR "08" PRIx64 34 typedef uint32_t word_t; 35 #endif 36 37 enum BacktraceUnwindErrorCode : uint32_t { 38 BACKTRACE_UNWIND_NO_ERROR, 39 // Something failed while trying to perform the setup to begin the unwind. 40 BACKTRACE_UNWIND_ERROR_SETUP_FAILED, 41 // There is no map information to use with the unwind. 42 BACKTRACE_UNWIND_ERROR_MAP_MISSING, 43 // An error occurred that indicates a programming error. 44 BACKTRACE_UNWIND_ERROR_INTERNAL, 45 // The thread to unwind has disappeared before the unwind can begin. 46 BACKTRACE_UNWIND_ERROR_THREAD_DOESNT_EXIST, 47 // The thread to unwind has not responded to a signal in a timely manner. 48 BACKTRACE_UNWIND_ERROR_THREAD_TIMEOUT, 49 // Attempt to do an unsupported operation. 50 BACKTRACE_UNWIND_ERROR_UNSUPPORTED_OPERATION, 51 // Attempt to do an offline unwind without a context. 52 BACKTRACE_UNWIND_ERROR_NO_CONTEXT, 53 // The count of frames exceed MAX_BACKTRACE_FRAMES. 54 BACKTRACE_UNWIND_ERROR_EXCEED_MAX_FRAMES_LIMIT, 55 // Failed to read memory. 56 BACKTRACE_UNWIND_ERROR_ACCESS_MEM_FAILED, 57 // Failed to read registers. 58 BACKTRACE_UNWIND_ERROR_ACCESS_REG_FAILED, 59 // Failed to find a function in debug sections. 60 BACKTRACE_UNWIND_ERROR_FIND_PROC_INFO_FAILED, 61 // Failed to execute dwarf instructions in debug sections. 62 BACKTRACE_UNWIND_ERROR_EXECUTE_DWARF_INSTRUCTION_FAILED, 63 // Unwind information is incorrect. 64 BACKTRACE_UNWIND_ERROR_UNWIND_INFO, 65 // Unwind information stopped due to sp/pc repeating. 66 BACKTRACE_UNWIND_ERROR_REPEATED_FRAME, 67 }; 68 69 struct BacktraceUnwindError { 70 enum BacktraceUnwindErrorCode error_code; 71 72 union { 73 // for BACKTRACE_UNWIND_ERROR_ACCESS_MEM_FAILED 74 uint64_t addr; 75 // for BACKTRACE_UNWIND_ERROR_ACCESS_REG_FAILED 76 uint64_t regno; 77 } error_info; 78 79 BacktraceUnwindError() : error_code(BACKTRACE_UNWIND_NO_ERROR) {} 80 }; 81 82 struct backtrace_frame_data_t { 83 size_t num; // The current fame number. 84 uint64_t pc; // The absolute pc. 85 uint64_t rel_pc; // The relative pc. 86 uint64_t sp; // The top of the stack. 87 size_t stack_size; // The size of the stack, zero indicate an unknown stack size. 88 backtrace_map_t map; // The map associated with the given pc. 89 std::string func_name; // The function name associated with this pc, NULL if not found. 90 uint64_t func_offset; // pc relative to the start of the function, only valid if func_name is not 91 // NULL. 92 }; 93 94 struct backtrace_stackinfo_t { 95 uint64_t start; 96 uint64_t end; 97 const uint8_t* data; 98 }; 99 100 namespace unwindstack { 101 class Regs; 102 } 103 104 class Backtrace { 105 public: 106 enum ArchEnum : uint8_t { 107 ARCH_ARM, 108 ARCH_ARM64, 109 ARCH_X86, 110 ARCH_X86_64, 111 }; 112 113 static void SetGlobalElfCache(bool enable); 114 115 // Create the correct Backtrace object based on what is to be unwound. 116 // If pid < 0 or equals the current pid, then the Backtrace object 117 // corresponds to the current process. 118 // If pid < 0 or equals the current pid and tid >= 0, then the Backtrace 119 // object corresponds to a thread in the current process. 120 // If pid >= 0 and tid < 0, then the Backtrace object corresponds to a 121 // different process. 122 // Tracing a thread in a different process is not supported. 123 // If map is NULL, then create the map and manage it internally. 124 // If map is not NULL, the map is still owned by the caller. 125 static Backtrace* Create(pid_t pid, pid_t tid, BacktraceMap* map = NULL); 126 127 // Create an offline Backtrace object that can be used to do an unwind without a process 128 // that is still running. By default, information is only cached in the map 129 // file. If the calling code creates the map, data can be cached between 130 // unwinds. If not, all cached data will be destroyed when the Backtrace 131 // object is destroyed. 132 static Backtrace* CreateOffline(ArchEnum arch, pid_t pid, pid_t tid, 133 const std::vector<backtrace_map_t>& maps, 134 const backtrace_stackinfo_t& stack); 135 static Backtrace* CreateOffline(ArchEnum arch, pid_t pid, pid_t tid, BacktraceMap* map); 136 137 // Create an offline Backtrace object that can be used to do an unwind without a process 138 // that is still running. If cache_file is set to true, then elf information will be cached 139 // for this call. The cached information survives until the calling process ends. This means 140 // that subsequent calls to create offline Backtrace objects will continue to use the same 141 // cache. It also assumes that the elf files used for each offline unwind are the same. 142 static Backtrace* CreateOffline(pid_t pid, pid_t tid, BacktraceMap* map, 143 const backtrace_stackinfo_t& stack, bool cache_file = false); 144 145 virtual ~Backtrace(); 146 147 // Get the current stack trace and store in the backtrace_ structure. 148 virtual bool Unwind(size_t num_ignore_frames, void* context = NULL) = 0; 149 150 static bool Unwind(unwindstack::Regs* regs, BacktraceMap* back_map, 151 std::vector<backtrace_frame_data_t>* frames, size_t num_ignore_frames, 152 std::vector<std::string>* skip_names, BacktraceUnwindError* error = nullptr); 153 154 static bool UnwindOffline(unwindstack::Regs* regs, BacktraceMap* back_map, 155 const backtrace_stackinfo_t& stack_info, 156 std::vector<backtrace_frame_data_t>* frames, 157 BacktraceUnwindError* error = nullptr); 158 159 // Get the function name and offset into the function given the pc. 160 // If the string is empty, then no valid function name was found, 161 // or the pc is not in any valid map. 162 virtual std::string GetFunctionName(uint64_t pc, uint64_t* offset, 163 const backtrace_map_t* map = NULL); 164 165 // Fill in the map data associated with the given pc. 166 virtual void FillInMap(uint64_t pc, backtrace_map_t* map); 167 168 // Read the data at a specific address. 169 virtual bool ReadWord(uint64_t ptr, word_t* out_value) = 0; 170 171 // Read arbitrary data from a specific address. If a read request would 172 // span from one map to another, this call only reads up until the end 173 // of the current map. 174 // Returns the total number of bytes actually read. 175 virtual size_t Read(uint64_t addr, uint8_t* buffer, size_t bytes) = 0; 176 177 // Create a string representing the formatted line of backtrace information 178 // for a single frame. 179 virtual std::string FormatFrameData(size_t frame_num); 180 static std::string FormatFrameData(const backtrace_frame_data_t* frame); 181 182 pid_t Pid() const { return pid_; } 183 pid_t Tid() const { return tid_; } 184 size_t NumFrames() const { return frames_.size(); } 185 186 const backtrace_frame_data_t* GetFrame(size_t frame_num) { 187 if (frame_num >= frames_.size()) { 188 return NULL; 189 } 190 return &frames_[frame_num]; 191 } 192 193 typedef std::vector<backtrace_frame_data_t>::iterator iterator; 194 iterator begin() { return frames_.begin(); } 195 iterator end() { return frames_.end(); } 196 197 typedef std::vector<backtrace_frame_data_t>::const_iterator const_iterator; 198 const_iterator begin() const { return frames_.begin(); } 199 const_iterator end() const { return frames_.end(); } 200 201 BacktraceMap* GetMap() { return map_; } 202 203 BacktraceUnwindError GetError() { return error_; } 204 205 std::string GetErrorString(BacktraceUnwindError error); 206 207 // Set whether to skip frames in libbacktrace/libunwindstack when doing a local unwind. 208 void SetSkipFrames(bool skip_frames) { skip_frames_ = skip_frames; } 209 210 protected: 211 Backtrace(pid_t pid, pid_t tid, BacktraceMap* map); 212 213 // The name returned is not demangled, GetFunctionName() takes care of 214 // demangling the name. 215 virtual std::string GetFunctionNameRaw(uint64_t pc, uint64_t* offset) = 0; 216 217 virtual bool VerifyReadWordArgs(uint64_t ptr, word_t* out_value); 218 219 bool BuildMap(); 220 221 pid_t pid_; 222 pid_t tid_; 223 224 BacktraceMap* map_; 225 bool map_shared_; 226 227 std::vector<backtrace_frame_data_t> frames_; 228 229 // Skip frames in libbacktrace/libunwindstack when doing a local unwind. 230 bool skip_frames_ = true; 231 232 BacktraceUnwindError error_; 233 }; 234 235 #endif // _BACKTRACE_BACKTRACE_H 236
