Have a modifed script i use for extracting strings from MSIL methods at runtime.
original source here https://web.archive.org/web/20200727042639/https://stackoverflow.com/questions/14243284/how-can-i-retrieve-string-literals-using-reflection#
I mainly modified it so it doesnt throw as many null refrence exceptions (see the // commented code pieces).
using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Reflection;
using System.Reflection.Emit;
using System.Runtime.InteropServices;
using System.Text;
//source of code https://web.archive.org/web/20200727042639/https://stackoverflow.com/questions/14243284/how-can-i-retrieve-string-literals-using-reflection#
class StringExtractors
{
public static IEnumerable<string> FindLiterals(MethodInfo method)
{
var reader = new ILReader(method);
foreach (var instruction in reader.Instructions)
{
if (instruction.Op == OpCodes.Ldstr)
{
yield return instruction.Data as string;
}
}
}
}
public interface IILReaderProvider
{
byte[] GetMethodBody();
FieldInfo ResolveField(int metadataToken);
MemberInfo ResolveMember(int metadataToken);
MethodBase ResolveMethod(int metadataToken);
byte[] ResolveSignature(int metadataToken);
string ResolveString(int metadataToken);
Type ResolveType(int metadataToken);
}
[StructLayout(LayoutKind.Sequential)]
public struct ILInstruction
{
private readonly OpCode
operationCode; // 40. 56-64. The entire structure is very big. maybe do array lookup for opcode instead.
private readonly byte[] instructionRawData;
private readonly object instructionData;
private readonly int instructionAddress;
private readonly int index;
internal ILInstruction(OpCode code, byte[] instructionRawData, int instructionAddress, object instructionData,
int index)
{
this.operationCode = code;
this.instructionRawData = instructionRawData;
this.instructionAddress = instructionAddress;
this.instructionData = instructionData;
this.index = index;
}
public OpCode Op
{
get { return this.operationCode; }
}
/// <summary>
/// Gets the raw data.
/// </summary>
public byte[] RawData
{
get { return this.instructionRawData; }
}
/// <summary>
/// Gets the data.
/// </summary>
public object Data
{
get { return this.instructionData; }
}
/// <summary>
/// Gets the address of the instruction.
/// </summary>
public int Address
{
get { return this.instructionAddress; }
}
/// <summary>
/// Gets the index of the instruction.
/// </summary>
/// <value>
/// The index of the instruction.
/// </value>
public int InstructionIndex => this.index;
/// <summary>
/// Gets the value as integer
/// </summary>
/// <value>The data value.</value>
public int DataValue
{
get
{
var value = 0;
if (this.Data == null) return value;
if (this.Data is byte)
{
value = (byte) Data;
}
else if (this.Data is short)
{
value = (short) this.Data;
}
else if (this.Data is int)
{
value = (int) this.Data;
}
return value;
}
}
/// <summary>
/// Gets the length of the instructions and operands.
/// </summary>
/// <value>The length.</value>
public int Length => this.Op.Size + (RawData?.Length ?? 0);
/// <summary>
/// Returns a <see cref="System.String"/> that represents this instance.
/// </summary>
/// <returns>
/// A <see cref="System.String"/> that represents this instance.
/// </returns>
public override string ToString()
{
var builder = new StringBuilder();
builder.AppendFormat("0x{0:x4} {1,-10}", this.Address, this.Op.Name);
if (this.Data != null)
{
builder.Append(this.Data);
}
if (this.RawData == null || this.RawData.Length <= 0) return builder.ToString();
builder.Append(" [0x");
for (var i = this.RawData.Length - 1; i >= 0; i--)
{
builder.Append(this.RawData[i].ToString("x2", CultureInfo.InvariantCulture));
}
builder.Append(']');
return builder.ToString();
}
}
/// <summary>
/// Reads IL instructions from a byte stream.
/// </summary>
/// <remarks>Allows generated code to be viewed without debugger or enabled debug assemblies.</remarks>
public sealed class ILReader
{
/// <summary>
/// The _instruction lookup.
/// </summary>
private static readonly Lazy<Dictionary<short, OpCode>> instructionLookup =
new Lazy<Dictionary<short, OpCode>>(ILReader.GetLookupTable,
System.Threading.LazyThreadSafetyMode.ExecutionAndPublication);
/// <summary>
/// The IL reader provider.
/// </summary>
private IILReaderProvider intermediateLanguageProvider;
/// <summary>
/// Initializes a new instance of the <see cref="ILReader"/> class.
/// </summary>
/// <param name="method">
/// The method.
/// </param>
public ILReader(MethodInfo method)
{
if (method == null)
{
throw new ArgumentNullException(nameof(method));
}
this.intermediateLanguageProvider = ILReader.CreateILReaderProvider(method);
}
/// <summary>
/// Gets the instructions.
/// </summary>
/// <value>The instructions.</value>
public IEnumerable<ILInstruction> Instructions
{
get
{
var instructionBytes = this.intermediateLanguageProvider.GetMethodBody();
int instructionIndex = 0, startAddress;
for (var position = 0; position < instructionBytes.Length;)
{
startAddress = position;
short operationData = instructionBytes[position];
if (IsInstructionPrefix(operationData))
{
operationData = (short) ((operationData << 8) | instructionBytes[++position]);
}
position++;
if (!instructionLookup.Value.TryGetValue(operationData, out var code))
{
throw new InvalidProgramException($"0x{operationData:X2} is not a valid op code.");
}
var dataSize = GetSize(code.OperandType);
var data = new byte[dataSize];
Buffer.BlockCopy(instructionBytes, position, data, 0, dataSize);
var objData = this.GetData(code, data);
position += dataSize;
if (code.OperandType == OperandType.InlineSwitch)
{
dataSize = (int) objData;
int[] labels = new int[dataSize];
for (int index = 0; index < labels.Length; index++)
{
labels[index] = BitConverter.ToInt32(instructionBytes, position);
position += 4;
}
objData = labels;
}
yield return new ILInstruction(code, data, startAddress, objData, instructionIndex);
instructionIndex++;
}
}
}
/// <summary>
/// Creates the IL reader provider.
/// </summary>
/// <param name="methodInfo">The MethodInfo object that represents the method to read..</param>
/// <returns>
/// The ILReader provider.
/// </returns>
private static IILReaderProvider CreateILReaderProvider(MethodInfo methodInfo)
{
IILReaderProvider reader = DynamicILReaderProvider.Create(methodInfo);
return reader ?? new ILReaderProvider(methodInfo);
}
/// <summary>
/// Checks to see if the IL instruction is a prefix indicating the length of the instruction is two bytes long.
/// </summary>
/// <param name="value">The IL instruction as a byte.</param>
/// <remarks>IL instructions can either be 1 or 2 bytes.</remarks>
/// <returns>True if this IL instruction is a prefix indicating the instruction is two bytes long.</returns>
private static bool IsInstructionPrefix(short value)
{
return ((value & OpCodes.Prefix1.Value) == OpCodes.Prefix1.Value) || ((value & OpCodes.Prefix2.Value) ==
OpCodes.Prefix2.Value)
|| ((value & OpCodes.Prefix3.Value) ==
OpCodes.Prefix3.Value) ||
((value & OpCodes.Prefix4.Value) ==
OpCodes.Prefix4.Value)
|| ((value & OpCodes.Prefix5.Value) ==
OpCodes.Prefix5.Value) ||
((value & OpCodes.Prefix6.Value) ==
OpCodes.Prefix6.Value)
|| ((value & OpCodes.Prefix7.Value) ==
OpCodes.Prefix7.Value) ||
((value & OpCodes.Prefixref.Value) ==
OpCodes.Prefixref.Value);
}
/// <summary>
/// The get lookup table.
/// </summary>
/// <returns>
/// A dictionary of IL instructions.
/// </returns>
private static Dictionary<short, OpCode> GetLookupTable()
{
// Might be better to do an array lookup. Use a seperate arrary for instructions without a prefix and array for each prefix.
var fields = typeof(OpCodes).GetFields(BindingFlags.Static | BindingFlags.Public);
return fields.Select(field => (OpCode) field.GetValue(null)).ToDictionary(code => code.Value);
}
/// <summary>
/// Gets the size of a operand.
/// </summary>
/// <param name="operandType">Defines the type of operand.</param>
/// <returns>The size in bytes of the operand type.</returns>
private static int GetSize(OperandType operandType)
{
switch (operandType)
{
case OperandType.InlineNone:
return 0;
case OperandType.ShortInlineBrTarget:
case OperandType.ShortInlineI:
case OperandType.ShortInlineVar:
return 1;
case OperandType.InlineVar:
return 2;
case OperandType.InlineBrTarget:
case OperandType.InlineField:
case OperandType.InlineI:
case OperandType.InlineMethod:
case OperandType.InlineSig:
case OperandType.InlineString:
case OperandType.InlineSwitch:
case OperandType.InlineTok:
case OperandType.InlineType:
case OperandType.ShortInlineR:
return 4;
case OperandType.InlineI8:
case OperandType.InlineR:
return 8;
default:
return 0;
}
}
private object GetData(OpCode code, byte[] rawData)
{
object data = null;
switch (code.OperandType)
{
case OperandType.InlineField:
data = this.intermediateLanguageProvider.ResolveField(BitConverter.ToInt32(rawData, 0));
break;
case OperandType.InlineSwitch:
data = BitConverter.ToInt32(rawData, 0);
break;
case OperandType.InlineBrTarget:
case OperandType.InlineI:
data = BitConverter.ToInt32(rawData, 0);
break;
case OperandType.InlineI8:
data = BitConverter.ToInt64(rawData, 0);
break;
case OperandType.InlineMethod:
data = this.intermediateLanguageProvider.ResolveMethod(BitConverter.ToInt32(rawData, 0));
break;
case OperandType.InlineR:
data = BitConverter.ToDouble(rawData, 0);
break;
case OperandType.InlineSig:
data = this.intermediateLanguageProvider.ResolveSignature(BitConverter.ToInt32(rawData, 0));
break;
case OperandType.InlineString:
data = this.intermediateLanguageProvider.ResolveString(BitConverter.ToInt32(rawData, 0));
break;
case OperandType.InlineTok:
case OperandType.InlineType:
data = this.intermediateLanguageProvider.ResolveType(BitConverter.ToInt32(rawData, 0));
break;
case OperandType.InlineVar:
data = BitConverter.ToInt16(rawData, 0);
break;
case OperandType.ShortInlineVar:
case OperandType.ShortInlineI:
case OperandType.ShortInlineBrTarget:
data = rawData[0];
break;
case OperandType.ShortInlineR:
data = BitConverter.ToSingle(rawData, 0);
break;
}
return data;
}
}
internal class DynamicILReaderProvider : IILReaderProvider
{
public const int TypeRidPrefix = 0x02000000;
public const int MethodRidPrefix = 0x06000000;
public const int FieldRidPrefix = 0x04000000;
public static readonly Type RuntimeDynamicMethodType;
private static readonly FieldInfo fileLengthField =
typeof(ILGenerator).GetField("m_length", BindingFlags.NonPublic | BindingFlags.Instance);
private static readonly FieldInfo IntermediateLanguageBytesField =
typeof(ILGenerator).GetField("m_ILStream", BindingFlags.NonPublic | BindingFlags.Instance);
private static readonly MethodInfo bakeByteArrayMethod =
typeof(ILGenerator).GetMethod("BakeByteArray", BindingFlags.NonPublic | BindingFlags.Instance);
private static readonly PropertyInfo dynamicScopeIndexor;
private static readonly FieldInfo dynamicScopeField;
private static readonly Type genericMethodInfoType;
private static readonly FieldInfo genericMethodHandleField;
private static readonly FieldInfo genericMethodContextField;
private static readonly Type varArgMethodType;
private static readonly FieldInfo varArgMethodMethod;
private static readonly Type genericFieldInfoType;
private static readonly FieldInfo genericFieldInfoHandle;
private static readonly FieldInfo genericFieldInfoContext;
private static readonly FieldInfo ownerField;
private object dynamicScope;
private ILGenerator generator;
static DynamicILReaderProvider()
{
// this section here with the comments is where i had to fix it
var bindingFlags = BindingFlags.NonPublic | BindingFlags.Instance;
//dynamicScopeIndexor = Type.GetType("System.Reflection.Emit.DynamicScope").GetProperty("Item", bindingFlags);
//dynamicScopeField = Type.GetType("System.Reflection.Emit.DynamicILGenerator").GetField("m_scope", bindingFlags);
//varArgMethodType = Type.GetType("System.Reflection.Emit.VarArgMethod");
//varArgMethodMethod = varArgMethodType.GetField("m_method", bindingFlags);
//genericMethodInfoType = Type.GetType("System.Reflection.Emit.GenericMethodInfo");
//genericMethodHandleField = genericMethodInfoType.GetField("m_methodHandle", bindingFlags);
//genericMethodContextField = genericMethodInfoType.GetField("m_context", bindingFlags);
// genericFieldInfoType = Type.GetType("System.Reflection.Emit.GenericFieldInfo", false);
// if (genericFieldInfoType != null)
// {
// genericFieldInfoHandle = genericFieldInfoType.GetField("m_fieldHandle", bindingFlags);
// genericFieldInfoContext = genericFieldInfoType.GetField("m_context", bindingFlags);
// }
// else
// {
// genericFieldInfoHandle = genericFieldInfoContext = null;
//}
RuntimeDynamicMethodType = typeof(DynamicMethod);
ownerField = RuntimeDynamicMethodType.GetField("m_owner", bindingFlags);
}
private DynamicILReaderProvider(DynamicMethod method)
{
this.Method = method;
this.generator = method.GetILGenerator();
this.dynamicScope = dynamicScopeField.GetValue(this.generator);
}
public DynamicMethod Method { get; private set; }
internal object this[int token]
{
get { return dynamicScopeIndexor.GetValue(this.dynamicScope, new object[] {token}); }
}
public static DynamicILReaderProvider Create(MethodInfo method)
{
if (method == null)
{
throw new ArgumentNullException(nameof(method));
}
var dynamicMethod = method as DynamicMethod;
if (dynamicMethod != null)
{
return new DynamicILReaderProvider(dynamicMethod);
}
var methodType = method.GetType();
if (RuntimeDynamicMethodType.IsAssignableFrom(methodType))
{
return new DynamicILReaderProvider(ownerField.GetValue(method) as DynamicMethod);
}
return null;
}
public byte[] GetMethodBody()
{
byte[] data = null;
var ilgen = this.Method.GetILGenerator();
try
{
data = (byte[]) bakeByteArrayMethod.Invoke(ilgen, null) ?? new byte[0];
}
catch (TargetInvocationException)
{
var length = (int) fileLengthField.GetValue(ilgen);
data = new byte[length];
Array.Copy((byte[]) IntermediateLanguageBytesField.GetValue(ilgen), data, length);
}
return data;
}
public FieldInfo ResolveField(int metadataToken)
{
var tokenValue = this[metadataToken];
if (tokenValue is RuntimeFieldHandle)
{
return FieldInfo.GetFieldFromHandle((RuntimeFieldHandle) tokenValue);
}
if (tokenValue.GetType() == DynamicILReaderProvider.genericFieldInfoType)
{
return FieldInfo.GetFieldFromHandle(
(RuntimeFieldHandle) genericFieldInfoHandle.GetValue(tokenValue),
(RuntimeTypeHandle) genericFieldInfoContext.GetValue(tokenValue));
}
return null;
}
public MemberInfo ResolveMember(int metadataToken)
{
if ((metadataToken & TypeRidPrefix) != 0)
{
return this.ResolveType(metadataToken);
}
if ((metadataToken & MethodRidPrefix) != 0)
{
return this.ResolveMethod(metadataToken);
}
if ((metadataToken & FieldRidPrefix) != 0)
{
return this.ResolveField(metadataToken);
}
return null;
}
public MethodBase ResolveMethod(int metadataToken)
{
var tokenValue = this[metadataToken];
DynamicMethod dynamicMethod = tokenValue as DynamicMethod;
if (dynamicMethod != null)
{
return dynamicMethod;
}
if (tokenValue is RuntimeMethodHandle)
{
return MethodBase.GetMethodFromHandle((RuntimeMethodHandle) this[metadataToken]);
}
if (tokenValue.GetType() == genericFieldInfoType)
{
return MethodBase.GetMethodFromHandle(
(RuntimeMethodHandle) genericMethodHandleField.GetValue(tokenValue),
(RuntimeTypeHandle) genericMethodContextField.GetValue(tokenValue));
}
if (tokenValue.GetType() == varArgMethodType)
{
return DynamicILReaderProvider.varArgMethodMethod.GetValue(tokenValue) as MethodInfo;
}
return null;
}
public byte[] ResolveSignature(int metadataToken)
{
return this[metadataToken] as byte[];
}
public string ResolveString(int metadataToken)
{
return this[metadataToken] as string;
}
public Type ResolveType(int metadataToken)
{
return Type.GetTypeFromHandle((RuntimeTypeHandle) this[metadataToken]);
}
}
internal class ILReaderProvider : IILReaderProvider
{
public ILReaderProvider(MethodInfo method)
{
this.Method = method;
this.MethodBody = method.GetMethodBody();
this.MethodModule = method.Module;
}
public MethodInfo Method { get; private set; }
public MethodBody MethodBody { get; private set; }
public Module MethodModule { get; private set; }
public byte[] GetMethodBody()
{
return this.MethodBody.GetILAsByteArray();
}
public FieldInfo ResolveField(int metadataToken)
{
return this.MethodModule.ResolveField(metadataToken);
}
public MemberInfo ResolveMember(int metadataToken)
{
return this.MethodModule.ResolveMember(metadataToken);
}
public MethodBase ResolveMethod(int metadataToken)
{
return this.MethodModule.ResolveMethod(metadataToken);
}
public byte[] ResolveSignature(int metadataToken)
{
return this.MethodModule.ResolveSignature(metadataToken);
}
public string ResolveString(int metadataToken)
{
return this.MethodModule.ResolveString(metadataToken);
}
public Type ResolveType(int metadataToken)
{
return this.MethodModule.ResolveType(metadataToken);
}
}
Hello @jfmherokiller, post with us on the DevTalk community. We like more of active folks like you who write programming contents.
It could be anywhere from thoughts on programming, experiences with software development, little projects, and any other coding projects.
The DevTalk community is dedicated to everything related to programming and software development.
Congratulations @jfmherokiller! You received a personal badge!
You can view your badges on your board And compare to others on the Ranking
Do not miss the last post from @hivebuzz: