111 lines
3.0 KiB
C#
111 lines
3.0 KiB
C#
/*
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Copyright (C) 2011-2015 de4dot@gmail.com
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This file is part of de4dot.
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de4dot is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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de4dot is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with de4dot. If not, see <http://www.gnu.org/licenses/>.
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*/
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using System.Collections.Generic;
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using dnlib.DotNet;
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using dnlib.DotNet.Emit;
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using de4dot.blocks;
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namespace de4dot.code.deobfuscators {
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public class ExceptionLoggerRemover {
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MethodDefAndDeclaringTypeDict<bool> exceptionLoggerMethods = new MethodDefAndDeclaringTypeDict<bool>();
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public int NumRemovedExceptionLoggers { get; set; }
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public void Add(MethodDef exceptionLogger) {
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exceptionLoggerMethods.Add(exceptionLogger, true);
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}
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bool Find(Blocks blocks, out TryBlock tryBlock) {
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tryBlock = null;
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foreach (var bb in blocks.MethodBlocks.BaseBlocks) {
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tryBlock = bb as TryBlock;
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if (tryBlock == null)
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continue;
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if (tryBlock.TryHandlerBlocks.Count != 1)
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continue;
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var catchBlock = tryBlock.TryHandlerBlocks[0];
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if (catchBlock.HandlerType != ExceptionHandlerType.Catch ||
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catchBlock.CatchType.FullName != "System.Exception") {
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continue;
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}
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if (catchBlock.BaseBlocks.Count != 1)
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continue;
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var handlerBlock = catchBlock.BaseBlocks[0] as HandlerBlock;
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if (handlerBlock == null)
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continue;
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int calls = 0;
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Instr callInstr = null;
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bool failed = false;
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foreach (var bb2 in handlerBlock.BaseBlocks) {
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var block = bb2 as Block;
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if (block == null) {
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failed = true;
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break;
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}
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foreach (var instr in block.Instructions) {
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switch (instr.OpCode.Code) {
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case Code.Call:
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case Code.Calli:
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case Code.Callvirt:
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calls++;
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callInstr = instr;
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break;
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}
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}
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}
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if (failed || calls != 1 || callInstr.OpCode.Code != Code.Call)
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continue;
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var calledMethod = callInstr.Operand as IMethod;
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if (calledMethod == null)
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continue;
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if (!IsExceptionLogger(calledMethod))
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continue;
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return true;
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}
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return false;
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}
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protected virtual bool IsExceptionLogger(IMethod method) {
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return exceptionLoggerMethods.Find(method);
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}
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protected virtual bool HasExceptionLoggers {
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get { return exceptionLoggerMethods.Count != 0; }
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}
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public bool Remove(Blocks blocks) {
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if (!HasExceptionLoggers)
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return false;
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TryBlock tryBlock;
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if (!Find(blocks, out tryBlock))
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return false;
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blocks.MethodBlocks.RemoveTryBlock(tryBlock);
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NumRemovedExceptionLoggers++;
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return true;
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}
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}
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}
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