BacktraceImpl.cpp revision e29609106033a48a6128664668d22bf4fb42a7ee
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#include <errno.h> 18#include <stdlib.h> 19#include <string.h> 20#include <sys/ptrace.h> 21#include <sys/types.h> 22#include <unistd.h> 23 24#include <string> 25 26#include <backtrace/Backtrace.h> 27#include <backtrace/BacktraceMap.h> 28 29#include "BacktraceImpl.h" 30#include "BacktraceLog.h" 31#include "thread_utils.h" 32 33//------------------------------------------------------------------------- 34// Backtrace functions. 35//------------------------------------------------------------------------- 36Backtrace::Backtrace(BacktraceImpl* impl, pid_t pid, BacktraceMap* map) 37 : pid_(pid), tid_(-1), map_(map), map_shared_(true), impl_(impl) { 38 impl_->SetParent(this); 39 40 if (map_ == NULL) { 41 map_ = BacktraceMap::Create(pid); 42 map_shared_ = false; 43 } 44} 45 46Backtrace::~Backtrace() { 47 if (impl_) { 48 delete impl_; 49 impl_ = NULL; 50 } 51 52 if (map_ && !map_shared_) { 53 delete map_; 54 map_ = NULL; 55 } 56} 57 58bool Backtrace::Unwind(size_t num_ignore_frames) { 59 return impl_->Unwind(num_ignore_frames); 60} 61 62extern "C" char* __cxa_demangle(const char* mangled, char* buf, size_t* len, 63 int* status); 64 65std::string Backtrace::GetFunctionName(uintptr_t pc, uintptr_t* offset) { 66 std::string func_name = impl_->GetFunctionNameRaw(pc, offset); 67 if (!func_name.empty()) { 68#if defined(__APPLE__) 69 // Mac OS' __cxa_demangle demangles "f" as "float"; last tested on 10.7. 70 if (func_name[0] != '_') { 71 return func_name; 72 } 73#endif 74 char* name = __cxa_demangle(func_name.c_str(), 0, 0, 0); 75 if (name) { 76 func_name = name; 77 free(name); 78 } 79 } 80 return func_name; 81} 82 83bool Backtrace::VerifyReadWordArgs(uintptr_t ptr, word_t* out_value) { 84 if (ptr & (sizeof(word_t)-1)) { 85 BACK_LOGW("invalid pointer %p", (void*)ptr); 86 *out_value = (word_t)-1; 87 return false; 88 } 89 return true; 90} 91 92std::string Backtrace::FormatFrameData(size_t frame_num) { 93 if (frame_num >= frames_.size()) { 94 return ""; 95 } 96 return FormatFrameData(&frames_[frame_num]); 97} 98 99std::string Backtrace::FormatFrameData(const backtrace_frame_data_t* frame) { 100 const char* map_name; 101 if (frame->map && !frame->map->name.empty()) { 102 map_name = frame->map->name.c_str(); 103 } else { 104 map_name = "<unknown>"; 105 } 106 107 uintptr_t relative_pc; 108 if (frame->map) { 109 relative_pc = frame->pc - frame->map->start; 110 } else { 111 relative_pc = frame->pc; 112 } 113 114 char buf[512]; 115 if (!frame->func_name.empty() && frame->func_offset) { 116 snprintf(buf, sizeof(buf), "#%02zu pc %0*" PRIxPTR " %s (%s+%" PRIuPTR ")", 117 frame->num, (int)sizeof(uintptr_t)*2, relative_pc, map_name, 118 frame->func_name.c_str(), frame->func_offset); 119 } else if (!frame->func_name.empty()) { 120 snprintf(buf, sizeof(buf), "#%02zu pc %0*" PRIxPTR " %s (%s)", frame->num, 121 (int)sizeof(uintptr_t)*2, relative_pc, map_name, frame->func_name.c_str()); 122 } else { 123 snprintf(buf, sizeof(buf), "#%02zu pc %0*" PRIxPTR " %s", frame->num, 124 (int)sizeof(uintptr_t)*2, relative_pc, map_name); 125 } 126 127 return buf; 128} 129 130const backtrace_map_t* Backtrace::FindMap(uintptr_t pc) { 131 return map_->Find(pc); 132} 133 134//------------------------------------------------------------------------- 135// BacktraceCurrent functions. 136//------------------------------------------------------------------------- 137BacktraceCurrent::BacktraceCurrent( 138 BacktraceImpl* impl, BacktraceMap* map) : Backtrace(impl, getpid(), map) { 139} 140 141BacktraceCurrent::~BacktraceCurrent() { 142} 143 144bool BacktraceCurrent::ReadWord(uintptr_t ptr, word_t* out_value) { 145 if (!VerifyReadWordArgs(ptr, out_value)) { 146 return false; 147 } 148 149 const backtrace_map_t* map = FindMap(ptr); 150 if (map && map->flags & PROT_READ) { 151 *out_value = *reinterpret_cast<word_t*>(ptr); 152 return true; 153 } else { 154 BACK_LOGW("pointer %p not in a readable map", reinterpret_cast<void*>(ptr)); 155 *out_value = static_cast<word_t>(-1); 156 return false; 157 } 158} 159 160//------------------------------------------------------------------------- 161// BacktracePtrace functions. 162//------------------------------------------------------------------------- 163BacktracePtrace::BacktracePtrace( 164 BacktraceImpl* impl, pid_t pid, pid_t tid, BacktraceMap* map) 165 : Backtrace(impl, pid, map) { 166 tid_ = tid; 167} 168 169BacktracePtrace::~BacktracePtrace() { 170} 171 172bool BacktracePtrace::ReadWord(uintptr_t ptr, word_t* out_value) { 173 if (!VerifyReadWordArgs(ptr, out_value)) { 174 return false; 175 } 176 177#if defined(__APPLE__) 178 BACK_LOGW("MacOS does not support reading from another pid."); 179 return false; 180#else 181 // ptrace() returns -1 and sets errno when the operation fails. 182 // To disambiguate -1 from a valid result, we clear errno beforehand. 183 errno = 0; 184 *out_value = ptrace(PTRACE_PEEKTEXT, Tid(), reinterpret_cast<void*>(ptr), NULL); 185 if (*out_value == static_cast<word_t>(-1) && errno) { 186 BACK_LOGW("invalid pointer %p reading from tid %d, ptrace() strerror(errno)=%s", 187 reinterpret_cast<void*>(ptr), Tid(), strerror(errno)); 188 return false; 189 } 190 return true; 191#endif 192} 193 194Backtrace* Backtrace::Create(pid_t pid, pid_t tid, BacktraceMap* map) { 195 if (pid == BACKTRACE_CURRENT_PROCESS || pid == getpid()) { 196 if (tid == BACKTRACE_CURRENT_THREAD || tid == gettid()) { 197 return CreateCurrentObj(map); 198 } else { 199 return CreateThreadObj(tid, map); 200 } 201 } else if (tid == BACKTRACE_CURRENT_THREAD) { 202 return CreatePtraceObj(pid, pid, map); 203 } else { 204 return CreatePtraceObj(pid, tid, map); 205 } 206} 207