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Add .mvid section to PE and remove dependency on MetadataReader #19133

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merged 9 commits into from
May 2, 2017
Merged

Add .mvid section to PE and remove dependency on MetadataReader #19133

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53a66be
Add .mvid section to PE and remove dependency on MetadataReader
Apr 30, 2017
67c31d3
Address PR feedback from Tomas and Jared
May 1, 2017
51a3c3f
Update refout docs
May 1, 2017
4de0d32
Address PR feedback from Tomas
jcouv May 1, 2017
ec9b2d4
Address PR feedback from Chuck and Aleksey
jcouv May 1, 2017
b1ac2aa
Clarify header format
jcouv May 1, 2017
4c02a2d
Add test for .mvid section not being first
jcouv May 2, 2017
7df9479
No end-of-stream exception
jcouv May 2, 2017
786dbe7
More feedback
jcouv May 2, 2017
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14 changes: 8 additions & 6 deletions src/Compilers/CSharp/Test/Emit/Emit/CompilationEmitTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -343,13 +343,15 @@ public void MvidSectionNotFirst()
peBlob.WriteContentTo(peStream);

peStream.Position = 0;
var peReader = new PEReader(peStream);
AssertEx.Equal(new[] { ".text", ".rsrc", ".reloc", ".mvid" },
peReader.PEHeaders.SectionHeaders.Select(h => h.Name));
using (var peReader = new PEReader(peStream))
{
AssertEx.Equal(new[] { ".text", ".rsrc", ".reloc", ".mvid" },
peReader.PEHeaders.SectionHeaders.Select(h => h.Name));

peStream.Position = 0;
var mvid = BuildTasks.MvidReader.ReadAssemblyMvidOrEmpty(peStream);
Assert.Equal(TestPEBuilder.s_mvid, mvid);
peStream.Position = 0;
var mvid = BuildTasks.MvidReader.ReadAssemblyMvidOrEmpty(peStream);
Assert.Equal(TestPEBuilder.s_mvid, mvid);
}
}

/// <summary>
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168 changes: 124 additions & 44 deletions src/Compilers/Core/MSBuildTask/MvidReader.cs
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Expand Up @@ -8,56 +8,78 @@ namespace Microsoft.CodeAnalysis.BuildTasks
{
public static class MvidReader
{
private static readonly Guid s_empty = Guid.Empty;

public static Guid ReadAssemblyMvidOrEmpty(Stream stream)
{
return ReadAssemblyMvidOrEmpty(new BinaryReader(stream));
}

private static Guid ReadAssemblyMvidOrEmpty(BinaryReader reader)
{
Guid empty = Guid.Empty;

// DOS Header (64), DOS Stub (64), PE Signature (4), COFF Header (20), PE Header (224), 1x Section Header (40)
if (reader.BaseStream.Length < 64 + 64 + 4 + 20 + 224 + 40)
{
return empty;
}

// DOS Header: Magic number (2)
if (reader.ReadUInt16() != 0x5a4d) // "MZ"
if (!ReadUInt16(reader, out ushort magicNumber) || magicNumber != 0x5a4d) // "MZ"
{
return empty;
return s_empty;
}

// DOS Header: Address of PE Signature (at 0x3C)
MoveTo(0x3C, reader);
uint lfanew = reader.ReadUInt32();
if (!MoveTo(0x3C, reader))
{
return s_empty;
}
if (!ReadUInt32(reader, out uint lfanew))
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Not sure what the variable name means. Perhaps 'signatureOffset' instead.

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That's what it's called in the spec, which I agree is not very informative. I'll fix.

{
return s_empty;
}

MoveTo(lfanew, reader); // jump over the MS DOS Stub to the PE Signature
// jump over the MS DOS Stub to the PE Signature
if (!MoveTo(lfanew, reader))
{
return s_empty;
}

// PE Signature ('P' 'E' null null)
if (reader.ReadUInt32() != 0x00004550)
if (!ReadUInt32(reader, out uint peSig) || peSig != 0x00004550)
{
return empty;
return s_empty;
}

// COFF Header: Machine (2)
Skip(2, reader);
if (!Skip(2, reader))
{
return s_empty;
}

// COFF Header: NumberOfSections (2)
ushort sections = reader.ReadUInt16();
if (!ReadUInt16(reader, out ushort sections))
{
return s_empty;
}

// COFF Header: TimeDateStamp (4), PointerToSymbolTable (4), NumberOfSymbols (4)
Skip(12, reader);
if (!Skip(12, reader))
{
return s_empty;
}

// COFF Header: OptionalHeaderSize (2)
ushort optionalHeaderSize = reader.ReadUInt16();
if (!ReadUInt16(reader, out ushort optionalHeaderSize))
{
return s_empty;
}

// COFF Header: Characteristics (2)
Skip(2, reader);
if (!Skip(2, reader))
{
return s_empty;
}

// Optional header
Skip(optionalHeaderSize, reader);
if (!Skip(optionalHeaderSize, reader))
{
return s_empty;
}

// Section headers
return FindMvidInSections(sections, reader);
Expand All @@ -67,58 +89,116 @@ private static Guid FindMvidInSections(ushort count, BinaryReader reader)
{
for (int i = 0; i < count; i++)
{

// .mvid section must be first, if it's there
// Section: Name (8)
byte[] name = reader.ReadBytes(8);
if (!ReadBytes(reader, 8, out byte[] name))
{
return s_empty;
}

if (name.Length == 8 && name[0] == '.' &&
name[1] == 'm' && name[2] == 'v' && name[3] == 'i' && name[4] == 'd' && name[5] == '\0')
{
// Section: VirtualSize (4)
uint virtualSize = reader.ReadUInt32();
if (!ReadUInt32(reader, out uint virtualSize) || virtualSize != 16)
{
// The .mvid section only stores a Guid
return s_empty;
}

// Section: VirtualAddress (4), SizeOfRawData (4)
Skip(8, reader);

// Section: PointerToRawData (4)
uint pointerToRawData = reader.ReadUInt32();

// The .mvid section only stores a Guid
if (virtualSize != 16)
if (!Skip(8, reader))
{
Debug.Assert(false);
return Guid.Empty;
return s_empty;
}

if (MoveTo(pointerToRawData, reader))
// Section: PointerToRawData (4)
if (!ReadUInt32(reader, out uint pointerToRawData))
{
byte[] guidBytes = new byte[16];
if (reader.BaseStream.Read(guidBytes, 0, 16) == 16)
{
return new Guid(guidBytes);
}
return s_empty;
}
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break;?


return ReadMvidSection(reader, pointerToRawData);
}
else
{
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@tmat tmat May 1, 2017 •
edited by jcouv
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Nit: no need for else since the if-statement returns #Resolved

// Section: VirtualSize (4), VirtualAddress (4), SizeOfRawData (4),
// PointerToRawData (4), PointerToRelocations (4), PointerToLineNumbers (4),
// NumberOfRelocations (2), NumberOfLineNumbers (2), Characteristics (4)
Skip(4 + 4 + 4 + 4 + 4 + 4 + 2 + 2 + 4, reader);
if (!Skip(4 + 4 + 4 + 4 + 4 + 4 + 2 + 2 + 4, reader))
{
return s_empty;
}
}
}

return Guid.Empty;
return s_empty;
}

private static Guid ReadMvidSection(BinaryReader reader, uint pointerToMvidSection)
{
if (!MoveTo(pointerToMvidSection, reader))
{
return s_empty;
}

if (!ReadBytes(reader, 16, out byte[] guidBytes))
{
return s_empty;
}

return new Guid(guidBytes);
}

private static void Skip(int bytes, BinaryReader reader)
private static bool ReadUInt16(BinaryReader reader, out ushort output)
{
if (reader.BaseStream.Position + 2 >= reader.BaseStream.Length)
{
output = 0;
return false;
}

output = reader.ReadUInt16();
return true;
}

private static bool ReadUInt32(BinaryReader reader, out uint output)
{
if (reader.BaseStream.Position + 4 >= reader.BaseStream.Length)
{
output = 0;
return false;
}

output = reader.ReadUInt32();
return true;
}

private static bool ReadBytes(BinaryReader reader, int count, out byte[] output)
{
if (reader.BaseStream.Position + count >= reader.BaseStream.Length)
{
output = null;
return false;
}

output = reader.ReadBytes(count);
return true;
}

private static bool Skip(int bytes, BinaryReader reader)
{
if (reader.BaseStream.Position + bytes >= reader.BaseStream.Length)
{
return false;
}

reader.BaseStream.Seek(bytes, SeekOrigin.Current);
return true;
}

private static bool MoveTo(uint position, BinaryReader reader)
{
if (reader.BaseStream.Length < position)
if (position >= reader.BaseStream.Length)
{
return false;
}
Expand Down