lib/Object/Minidump.cpp

   1 //===- Minidump.cpp - Minidump object file implementation -----------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "llvm/Object/Minidump.h"
  10 #include "llvm/Object/Error.h"
  11 #include "llvm/Support/ConvertUTF.h"
  12
  13 using namespace llvm;
  14 using namespace llvm::object;
  15 using namespace llvm::minidump;
  16
  17 Optional<ArrayRef<uint8_t>>
  18 MinidumpFile::getRawStream(minidump::StreamType Type) const {
  19   auto It = StreamMap.find(Type);
  20   if (It != StreamMap.end())
  21     return getRawStream(Streams[It->second]);
  22   return None;
  23 }
  24
  25 Expected<std::string> MinidumpFile::getString(size_t Offset) const {
  26   // Minidump strings consist of a 32-bit length field, which gives the size of
  27   // the string in *bytes*. This is followed by the actual string encoded in
  28   // UTF16.
  29   auto ExpectedSize =
  30       getDataSliceAs<support::ulittle32_t>(getData(), Offset, 1);
  31   if (!ExpectedSize)
  32     return ExpectedSize.takeError();
  33   size_t Size = (*ExpectedSize)[0];
  34   if (Size % 2 != 0)
  35     return createError("String size not even");
  36   Size /= 2;
  37   if (Size == 0)
  38     return "";
  39
  40   Offset += sizeof(support::ulittle32_t);
  41   auto ExpectedData =
  42       getDataSliceAs<support::ulittle16_t>(getData(), Offset, Size);
  43   if (!ExpectedData)
  44     return ExpectedData.takeError();
  45
  46   SmallVector<UTF16, 32> WStr(Size);
  47   copy(*ExpectedData, WStr.begin());
  48
  49   std::string Result;
  50   if (!convertUTF16ToUTF8String(WStr, Result))
  51     return createError("String decoding failed");
  52
  53   return Result;
  54 }
  55
  56 template <typename T>
  57 Expected<ArrayRef<T>> MinidumpFile::getListStream(StreamType Stream) const {
  58   auto OptionalStream = getRawStream(Stream);
  59   if (!OptionalStream)
  60     return createError("No such stream");
  61   auto ExpectedSize =
  62       getDataSliceAs<support::ulittle32_t>(*OptionalStream, 0, 1);
  63   if (!ExpectedSize)
  64     return ExpectedSize.takeError();
  65
  66   size_t ListSize = ExpectedSize.get()[0];
  67
  68   size_t ListOffset = 4;
  69   // Some producers insert additional padding bytes to align the list to an
  70   // 8-byte boundary. Check for that by comparing the list size with the overall
  71   // stream size.
  72   if (ListOffset + sizeof(T) * ListSize < OptionalStream->size())
  73     ListOffset = 8;
  74
  75   return getDataSliceAs<T>(*OptionalStream, ListOffset, ListSize);
  76 }
  77 template Expected<ArrayRef<Module>>
  78     MinidumpFile::getListStream(StreamType) const;
  79 template Expected<ArrayRef<Thread>>
  80     MinidumpFile::getListStream(StreamType) const;
  81
  82 Expected<ArrayRef<uint8_t>>
  83 MinidumpFile::getDataSlice(ArrayRef<uint8_t> Data, size_t Offset, size_t Size) {
  84   // Check for overflow.
  85   if (Offset + Size < Offset || Offset + Size < Size ||
  86       Offset + Size > Data.size())
  87     return createEOFError();
  88   return Data.slice(Offset, Size);
  89 }
  90
  91 Expected<std::unique_ptr<MinidumpFile>>
  92 MinidumpFile::create(MemoryBufferRef Source) {
  93   ArrayRef<uint8_t> Data = arrayRefFromStringRef(Source.getBuffer());
  94   auto ExpectedHeader = getDataSliceAs<minidump::Header>(Data, 0, 1);
  95   if (!ExpectedHeader)
  96     return ExpectedHeader.takeError();
  97
  98   const minidump::Header &Hdr = (*ExpectedHeader)[0];
  99   if (Hdr.Signature != Header::MagicSignature)
 100     return createError("Invalid signature");
 101   if ((Hdr.Version & 0xffff) != Header::MagicVersion)
 102     return createError("Invalid version");
 103
 104   auto ExpectedStreams = getDataSliceAs<Directory>(Data, Hdr.StreamDirectoryRVA,
 105                                                    Hdr.NumberOfStreams);
 106   if (!ExpectedStreams)
 107     return ExpectedStreams.takeError();
 108
 109   DenseMap<StreamType, std::size_t> StreamMap;
 110   for (const auto &Stream : llvm::enumerate(*ExpectedStreams)) {
 111     StreamType Type = Stream.value().Type;
 112     const LocationDescriptor &Loc = Stream.value().Location;
 113
 114     auto ExpectedStream = getDataSlice(Data, Loc.RVA, Loc.DataSize);
 115     if (!ExpectedStream)
 116       return ExpectedStream.takeError();
 117
 118     if (Type == StreamType::Unused && Loc.DataSize == 0) {
 119       // Ignore dummy streams. This is technically ill-formed, but a number of
 120       // existing minidumps seem to contain such streams.
 121       continue;
 122     }
 123
 124     if (Type == DenseMapInfo<StreamType>::getEmptyKey() ||
 125         Type == DenseMapInfo<StreamType>::getTombstoneKey())
 126       return createError("Cannot handle one of the minidump streams");
 127
 128     // Update the directory map, checking for duplicate stream types.
 129     if (!StreamMap.try_emplace(Type, Stream.index()).second)
 130       return createError("Duplicate stream type");
 131   }
 132
 133   return std::unique_ptr<MinidumpFile>(
 134       new MinidumpFile(Source, Hdr, *ExpectedStreams, std::move(StreamMap)));
 135 }