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      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 <inttypes.h>
     18 #include <stdint.h>
     19 #include <stdlib.h>
     20 #include <sys/types.h>
     21 #include <ucontext.h>
     22 
     23 #include <string>
     24 
     25 #include <android-base/stringprintf.h>
     26 
     27 #include <backtrace/Backtrace.h>
     28 #include <backtrace/BacktraceMap.h>
     29 
     30 #include "BacktraceLog.h"
     31 #include "thread_utils.h"
     32 #include "UnwindCurrent.h"
     33 #include "UnwindPtrace.h"
     34 
     35 using android::base::StringPrintf;
     36 
     37 //-------------------------------------------------------------------------
     38 // Backtrace functions.
     39 //-------------------------------------------------------------------------
     40 Backtrace::Backtrace(pid_t pid, pid_t tid, BacktraceMap* map)
     41     : pid_(pid), tid_(tid), map_(map), map_shared_(true) {
     42   if (map_ == nullptr) {
     43     map_ = BacktraceMap::Create(pid);
     44     map_shared_ = false;
     45   }
     46 }
     47 
     48 Backtrace::~Backtrace() {
     49   if (map_ && !map_shared_) {
     50     delete map_;
     51     map_ = nullptr;
     52   }
     53 }
     54 
     55 std::string Backtrace::GetFunctionName(uintptr_t pc, uintptr_t* offset) {
     56   std::string func_name = GetFunctionNameRaw(pc, offset);
     57   return func_name;
     58 }
     59 
     60 bool Backtrace::VerifyReadWordArgs(uintptr_t ptr, word_t* out_value) {
     61   if (ptr & (sizeof(word_t)-1)) {
     62     BACK_LOGW("invalid pointer %p", reinterpret_cast<void*>(ptr));
     63     *out_value = static_cast<word_t>(-1);
     64     return false;
     65   }
     66   return true;
     67 }
     68 
     69 std::string Backtrace::FormatFrameData(size_t frame_num) {
     70   if (frame_num >= frames_.size()) {
     71     return "";
     72   }
     73   return FormatFrameData(&frames_[frame_num]);
     74 }
     75 
     76 std::string Backtrace::FormatFrameData(const backtrace_frame_data_t* frame) {
     77   uintptr_t relative_pc;
     78   std::string map_name;
     79   if (BacktraceMap::IsValid(frame->map)) {
     80     relative_pc = BacktraceMap::GetRelativePc(frame->map, frame->pc);
     81     if (!frame->map.name.empty()) {
     82       map_name = frame->map.name.c_str();
     83       if (map_name[0] == '[' && map_name[map_name.size() - 1] == ']') {
     84         map_name.resize(map_name.size() - 1);
     85         map_name += StringPrintf(":%" PRIPTR "]", frame->map.start);
     86       }
     87     } else {
     88       map_name = StringPrintf("<anonymous:%" PRIPTR ">", frame->map.start);
     89     }
     90   } else {
     91     map_name = "<unknown>";
     92     relative_pc = frame->pc;
     93   }
     94 
     95   std::string line(StringPrintf("#%02zu pc %" PRIPTR "  ", frame->num, relative_pc));
     96   line += map_name;
     97   // Special handling for non-zero offset maps, we need to print that
     98   // information.
     99   if (frame->map.offset != 0) {
    100     line += " (offset " + StringPrintf("0x%" PRIxPTR, frame->map.offset) + ")";
    101   }
    102   if (!frame->func_name.empty()) {
    103     line += " (" + frame->func_name;
    104     if (frame->func_offset) {
    105       line += StringPrintf("+%" PRIuPTR, frame->func_offset);
    106     }
    107     line += ')';
    108   }
    109 
    110   return line;
    111 }
    112 
    113 void Backtrace::FillInMap(uintptr_t pc, backtrace_map_t* map) {
    114   if (map_ != nullptr) {
    115     map_->FillIn(pc, map);
    116   }
    117 }
    118 
    119 Backtrace* Backtrace::Create(pid_t pid, pid_t tid, BacktraceMap* map) {
    120   if (pid == BACKTRACE_CURRENT_PROCESS) {
    121     pid = getpid();
    122     if (tid == BACKTRACE_CURRENT_THREAD) {
    123       tid = gettid();
    124     }
    125   } else if (tid == BACKTRACE_CURRENT_THREAD) {
    126     tid = pid;
    127   }
    128 
    129   if (pid == getpid()) {
    130     return new UnwindCurrent(pid, tid, map);
    131   } else {
    132     return new UnwindPtrace(pid, tid, map);
    133   }
    134 }
    135 
    136 std::string Backtrace::GetErrorString(BacktraceUnwindError error) {
    137   switch (error) {
    138   case BACKTRACE_UNWIND_NO_ERROR:
    139     return "No error";
    140   case BACKTRACE_UNWIND_ERROR_SETUP_FAILED:
    141     return "Setup failed";
    142   case BACKTRACE_UNWIND_ERROR_MAP_MISSING:
    143     return "No map found";
    144   case BACKTRACE_UNWIND_ERROR_INTERNAL:
    145     return "Internal libbacktrace error, please submit a bugreport";
    146   case BACKTRACE_UNWIND_ERROR_THREAD_DOESNT_EXIST:
    147     return "Thread doesn't exist";
    148   case BACKTRACE_UNWIND_ERROR_THREAD_TIMEOUT:
    149     return "Thread has not repsonded to signal in time";
    150   case BACKTRACE_UNWIND_ERROR_UNSUPPORTED_OPERATION:
    151     return "Attempt to use an unsupported feature";
    152   case BACKTRACE_UNWIND_ERROR_NO_CONTEXT:
    153     return "Attempt to do an offline unwind without a context";
    154   }
    155 }
    156