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 }
136