1    :  // Copyright 2015 Google Inc. All Rights Reserved.
   2    :  //
   3    :  // Licensed under the Apache License, Version 2.0 (the "License");
   4    :  // you may not use this file except in compliance with the License.
   5    :  // You may obtain a copy of the License at
   6    :  //
   7    :  //     http://www.apache.org/licenses/LICENSE-2.0
   8    :  //
   9    :  // Unless required by applicable law or agreed to in writing, software
  10    :  // distributed under the License is distributed on an "AS IS" BASIS,
  11    :  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12    :  // See the License for the specific language governing permissions and
  13    :  // limitations under the License.
  14    :  
  15    :  #include "syzygy/minidump/minidump.h"
  16    :  
  17    :  #include "base/logging.h"
  18    :  #include "base/files/file_util.h"
  19    :  
  20    :  namespace minidump {
  21    :  
  22  E :  Minidump::Minidump() {
  23  E :  }
  24    :  
  25  E :  Minidump::~Minidump() {
  26  E :  }
  27    :  
  28  E :  bool Minidump::Open(const base::FilePath& path) {
  29  E :    file_.reset(base::OpenFile(path, "rb"));
  30    :  
  31  E :    if (!file_)
  32  E :      return false;
  33    :  
  34    :    // Read the header and validate the signature.
  35  E :    MINIDUMP_HEADER header = {};
  36  E :    if (!ReadBytes(0, sizeof(header), &header))
  37  E :      return false;
  38    :  
  39  E :    if (header.Signature != MINIDUMP_SIGNATURE || header.NumberOfStreams == 0) {
  40  E :      return false;
  41    :    }
  42    :  
  43  E :    directory_.resize(header.NumberOfStreams);
  44    :    if (!ReadBytes(header.StreamDirectoryRva,
  45    :                   header.NumberOfStreams * sizeof(directory_[0]),
  46  E :                   &directory_.at(0))) {
  47  E :      return false;
  48    :    }
  49    :  
  50  E :    return true;
  51  E :  }
  52    :  
  53    :  Minidump::Stream Minidump::GetStreamFor(
  54  E :      const MINIDUMP_LOCATION_DESCRIPTOR& location) const {
  55  E :    return Stream(this, location.Rva, location.DataSize, kNoStreamId);
  56  E :  }
  57    :  
  58  E :  Minidump::Stream Minidump::GetStream(size_t stream_id) const {
  59  E :    DCHECK_GT(directory_.size(), stream_id);
  60  E :    const MINIDUMP_DIRECTORY& dir_entry = directory_[stream_id];
  61    :  
  62    :    return Stream(this, dir_entry.Location.Rva, dir_entry.Location.DataSize,
  63  E :                  stream_id);
  64  E :  }
  65    :  
  66    :  Minidump::Stream Minidump::FindNextStream(const Stream* prev,
  67  E :                                            size_t stream_type) const {
  68  E :    size_t start = prev ? prev->stream_id() + 1 : 0;
  69    :  
  70  E :    for (size_t id = start; id < directory_.size(); ++id) {
  71  E :      if (directory_[id].StreamType == stream_type)
  72  E :        return GetStream(id);
  73  E :    }
  74    :  
  75    :    // Not found, return an invalid stream.
  76  E :    return Stream();
  77  E :  }
  78    :  
  79  E :  bool Minidump::ReadBytes(size_t offset, size_t data_size, void* data) const {
  80  E :    if (fseek(file_.get(), offset, SEEK_SET) != 0)
  81  i :      return false;
  82    :  
  83  E :    if (fread(data, 1, data_size, file_.get()) != data_size)
  84  E :      return false;
  85    :  
  86  E :    return true;
  87  E :  }
  88    :  
  89    :  Minidump::Stream::Stream()
  90    :      : minidump_(nullptr),
  91    :        current_offset_(0),
  92    :        remaining_length_(0),
  93  E :        stream_id_(0) {
  94  E :  }
  95    :  
  96    :  Minidump::Stream::Stream(
  97    :      const Minidump* minidump, size_t offset, size_t length, size_t stream_id)
  98    :          : minidump_(minidump),
  99    :            current_offset_(offset),
 100    :            remaining_length_(length),
 101  E :            stream_id_(stream_id) {
 102  E :    DCHECK_NE(static_cast<Minidump*>(nullptr), minidump);
 103  E :  }
 104    :  
 105  E :  bool Minidump::Stream::ReadBytes(size_t data_len, void* data) {
 106  E :    DCHECK(minidump_ != nullptr);
 107    :  
 108  E :    if (data_len > remaining_length_)
 109  E :      return false;
 110    :  
 111  E :    if (!minidump_->ReadBytes(current_offset_, data_len, data))
 112  i :      return false;
 113    :  
 114  E :    current_offset_ += data_len;
 115  E :    remaining_length_ -= data_len;
 116    :  
 117  E :    return true;
 118  E :  }
 119    :  
 120  E :  bool Minidump::Stream::ReadBytes(size_t data_len, std::string* data) {
 121  E :    DCHECK(minidump_ != nullptr);
 122  E :    DCHECK(data != nullptr);
 123    :  
 124  E :    data->resize(data_len);
 125  E :    bool success = ReadBytes(data_len, &data->at(0));
 126  E :    if (!success)
 127  i :      data->resize(0);
 128    :  
 129  E :    return success;
 130  E :  }
 131    :  
 132  E :  bool Minidump::Stream::ReadString(std::wstring* data) {
 133  E :    DCHECK(minidump_ != nullptr);
 134  E :    DCHECK(data != nullptr);
 135    :  
 136  E :    ULONG32 size_bytes = 0U;
 137  E :    if (!ReadElement(&size_bytes))
 138  i :      return false;
 139    :  
 140    :    // Increment to account for (consume) null-terminating character.
 141  E :    size_bytes += sizeof(wchar_t);
 142  E :    if (size_bytes % sizeof(wchar_t))
 143  i :      return false;
 144  E :    size_t num_characters = size_bytes / sizeof(wchar_t);
 145    :  
 146  E :    std::wstring buffer;
 147  E :    buffer.resize(num_characters);
 148  E :    if (!ReadBytes(size_bytes, &buffer.at(0)))
 149  i :      return false;
 150    :  
 151    :    // Drop the extra null-terminating character.
 152  E :    buffer.resize(num_characters - 1);
 153  E :    buffer.swap(*data);
 154  E :    return true;
 155  E :  }
 156    :  
 157    :  }  // namespace minidump