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 // Unwind information stopped due to invalid elf. 68 BACKTRACE_UNWIND_ERROR_INVALID_ELF, 69 }; 70 71 struct BacktraceUnwindError { 72 enum BacktraceUnwindErrorCode error_code; 73 74 union { 75 // for BACKTRACE_UNWIND_ERROR_ACCESS_MEM_FAILED 76 uint64_t addr; 77 // for BACKTRACE_UNWIND_ERROR_ACCESS_REG_FAILED 78 uint64_t regno; 79 } error_info; 80 BacktraceUnwindErrorBacktraceUnwindError81 BacktraceUnwindError() : error_code(BACKTRACE_UNWIND_NO_ERROR) {} 82 }; 83 84 struct backtrace_frame_data_t { 85 size_t num; // The current fame number. 86 uint64_t pc; // The absolute pc. 87 uint64_t rel_pc; // The relative pc. 88 uint64_t sp; // The top of the stack. 89 size_t stack_size; // The size of the stack, zero indicate an unknown stack size. 90 backtrace_map_t map; // The map associated with the given pc. 91 std::string func_name; // The function name associated with this pc, NULL if not found. 92 uint64_t func_offset; // pc relative to the start of the function, only valid if func_name is not 93 // NULL. 94 }; 95 96 struct backtrace_stackinfo_t { 97 uint64_t start; 98 uint64_t end; 99 const uint8_t* data; 100 }; 101 102 namespace unwindstack { 103 class Regs; 104 } 105 106 class Backtrace { 107 public: 108 enum ArchEnum : uint8_t { 109 ARCH_ARM, 110 ARCH_ARM64, 111 ARCH_X86, 112 ARCH_X86_64, 113 }; 114 115 static void SetGlobalElfCache(bool enable); 116 117 // Create the correct Backtrace object based on what is to be unwound. 118 // If pid < 0 or equals the current pid, then the Backtrace object 119 // corresponds to the current process. 120 // If pid < 0 or equals the current pid and tid >= 0, then the Backtrace 121 // object corresponds to a thread in the current process. 122 // If pid >= 0 and tid < 0, then the Backtrace object corresponds to a 123 // different process. 124 // Tracing a thread in a different process is not supported. 125 // If map is NULL, then create the map and manage it internally. 126 // If map is not NULL, the map is still owned by the caller. 127 static Backtrace* Create(pid_t pid, pid_t tid, BacktraceMap* map = nullptr); 128 129 // Create an offline Backtrace object that can be used to do an unwind without a process 130 // that is still running. By default, information is only cached in the map 131 // file. If the calling code creates the map, data can be cached between 132 // unwinds. If not, all cached data will be destroyed when the Backtrace 133 // object is destroyed. 134 static Backtrace* CreateOffline(ArchEnum arch, pid_t pid, pid_t tid, 135 const std::vector<backtrace_map_t>& maps, 136 const backtrace_stackinfo_t& stack); 137 static Backtrace* CreateOffline(ArchEnum arch, pid_t pid, pid_t tid, BacktraceMap* map); 138 139 // Create an offline Backtrace object that can be used to do an unwind without a process 140 // that is still running. If cache_file is set to true, then elf information will be cached 141 // for this call. The cached information survives until the calling process ends. This means 142 // that subsequent calls to create offline Backtrace objects will continue to use the same 143 // cache. It also assumes that the elf files used for each offline unwind are the same. 144 static Backtrace* CreateOffline(pid_t pid, pid_t tid, BacktraceMap* map, 145 const backtrace_stackinfo_t& stack, bool cache_file = false); 146 147 virtual ~Backtrace(); 148 149 // Get the current stack trace and store in the backtrace_ structure. 150 virtual bool Unwind(size_t num_ignore_frames, void* context = nullptr) = 0; 151 152 static bool Unwind(unwindstack::Regs* regs, BacktraceMap* back_map, 153 std::vector<backtrace_frame_data_t>* frames, size_t num_ignore_frames, 154 std::vector<std::string>* skip_names, BacktraceUnwindError* error = nullptr); 155 156 static bool UnwindOffline(unwindstack::Regs* regs, BacktraceMap* back_map, 157 const backtrace_stackinfo_t& stack_info, 158 std::vector<backtrace_frame_data_t>* frames, 159 BacktraceUnwindError* error = nullptr); 160 161 // Get the function name and offset into the function given the pc. 162 // If the string is empty, then no valid function name was found, 163 // or the pc is not in any valid map. 164 virtual std::string GetFunctionName(uint64_t pc, uint64_t* offset, 165 const backtrace_map_t* map = nullptr); 166 167 // Fill in the map data associated with the given pc. 168 virtual void FillInMap(uint64_t pc, backtrace_map_t* map); 169 170 // Read the data at a specific address. 171 virtual bool ReadWord(uint64_t ptr, word_t* out_value) = 0; 172 173 // Read arbitrary data from a specific address. If a read request would 174 // span from one map to another, this call only reads up until the end 175 // of the current map. 176 // Returns the total number of bytes actually read. 177 virtual size_t Read(uint64_t addr, uint8_t* buffer, size_t bytes) = 0; 178 179 // Create a string representing the formatted line of backtrace information 180 // for a single frame. 181 virtual std::string FormatFrameData(size_t frame_num); 182 static std::string FormatFrameData(const backtrace_frame_data_t* frame); 183 Pid()184 pid_t Pid() const { return pid_; } Tid()185 pid_t Tid() const { return tid_; } NumFrames()186 size_t NumFrames() const { return frames_.size(); } 187 GetFrame(size_t frame_num)188 const backtrace_frame_data_t* GetFrame(size_t frame_num) { 189 if (frame_num >= frames_.size()) { 190 return nullptr; 191 } 192 return &frames_[frame_num]; 193 } 194 195 typedef std::vector<backtrace_frame_data_t>::iterator iterator; begin()196 iterator begin() { return frames_.begin(); } end()197 iterator end() { return frames_.end(); } 198 199 typedef std::vector<backtrace_frame_data_t>::const_iterator const_iterator; begin()200 const_iterator begin() const { return frames_.begin(); } end()201 const_iterator end() const { return frames_.end(); } 202 GetMap()203 BacktraceMap* GetMap() { return map_; } 204 GetError()205 BacktraceUnwindError GetError() { return error_; } 206 207 std::string GetErrorString(BacktraceUnwindError error); 208 209 // Set whether to skip frames in libbacktrace/libunwindstack when doing a local unwind. SetSkipFrames(bool skip_frames)210 void SetSkipFrames(bool skip_frames) { skip_frames_ = skip_frames; } 211 212 protected: 213 Backtrace(pid_t pid, pid_t tid, BacktraceMap* map); 214 215 // The name returned is not demangled, GetFunctionName() takes care of 216 // demangling the name. 217 virtual std::string GetFunctionNameRaw(uint64_t pc, uint64_t* offset) = 0; 218 219 virtual bool VerifyReadWordArgs(uint64_t ptr, word_t* out_value); 220 221 bool BuildMap(); 222 223 pid_t pid_; 224 pid_t tid_; 225 226 BacktraceMap* map_; 227 bool map_shared_; 228 229 std::vector<backtrace_frame_data_t> frames_; 230 231 // Skip frames in libbacktrace/libunwindstack when doing a local unwind. 232 bool skip_frames_ = true; 233 234 BacktraceUnwindError error_; 235 }; 236 237 #endif // _BACKTRACE_BACKTRACE_H 238