Cstrike: Import some memory tools from SourceMod

public/memtools/CDetour/detours.cpp

@@ -0,0 +1,231 @@
+/**
+* vim: set ts=4 :
+* =============================================================================
+* SourceMod
+* Copyright (C) 2004-2010 AlliedModders LLC.  All rights reserved.
+* =============================================================================
+*
+* This program is free software; you can redistribute it and/or modify it under
+* the terms of the GNU General Public License, version 3.0, as published by the
+* Free Software Foundation.
+* 
+* This program is distributed in the hope that it will be useful, but WITHOUT
+* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+* FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+* details.
+*
+* You should have received a copy of the GNU General Public License along with
+* this program.  If not, see <http://www.gnu.org/licenses/>.
+*
+* As a special exception, AlliedModders LLC gives you permission to link the
+* code of this program (as well as its derivative works) to "Half-Life 2," the
+* "Source Engine," the "SourcePawn JIT," and any Game MODs that run on software
+* by the Valve Corporation.  You must obey the GNU General Public License in
+* all respects for all other code used.  Additionally, AlliedModders LLC grants
+* this exception to all derivative works.  AlliedModders LLC defines further
+* exceptions, found in LICENSE.txt (as of this writing, version JULY-31-2007),
+* or <http://www.sourcemod.net/license.php>.
+*
+* Version: $Id: detours.cpp 248 2008-08-27 00:56:22Z pred $
+*/
+
+#include "detours.h"
+#include "asm/asm.h"
+
+//ISourcePawnEngine *CDetourManager::spengine = NULL;
+//IGameConfig *CDetourManager::gameconf = NULL;
+
+void CDetourManager::Init(/*ISourcePawnEngine *spengine, IGameConfig *gameconf*/)
+{
+	//CDetourManager::spengine = spengine;
+	//CDetourManager::gameconf = gameconf;
+}
+
+CDetour *CDetourManager::CreateDetour(void *callbackfunction, void **trampoline, const char *signame)
+{
+	CDetour *detour = new CDetour(callbackfunction, trampoline, signame);
+	if (detour)
+	{
+		if (!detour->Init(/*spengine, gameconf*/))
+		{
+			delete detour;
+			return NULL;
+		}
+
+		return detour;
+	}
+
+	return NULL;
+}
+
+CDetour *CDetourManager::CreateDetour(void *callbackfunction, void **trampoline, void *address)
+{
+	CDetour *detour = new CDetour(callbackfunction, trampoline, address);
+	if (detour)
+	{
+		if (!detour->Init(/*spengine, gameconf*/))
+		{
+			delete detour;
+			return NULL;
+		}
+
+		return detour;
+	}
+
+	return NULL;
+}
+
+
+CDetour::CDetour(void *callbackfunction, void **trampoline, const char *signame)
+{
+	enabled = false;
+	detoured = false;
+	detour_address = NULL;
+	detour_trampoline = NULL;
+	this->signame = signame;
+	this->detour_callback = callbackfunction;
+	this->address = NULL;
+	//spengine = NULL;
+	//gameconf = NULL;
+	this->trampoline = trampoline;
+}
+
+CDetour::CDetour(void *callbackfunction, void **trampoline, void *address)
+{
+	enabled = false;
+	detoured = false;
+	detour_address = address;
+	detour_trampoline = NULL;
+	this->signame = NULL;
+	this->detour_callback = callbackfunction;
+	this->address = address;
+	//spengine = NULL;
+	//gameconf = NULL;
+	this->trampoline = trampoline;
+}
+
+
+bool CDetour::Init(/*ISourcePawnEngine *spengine, IGameConfig *gameconf*/)
+{
+	//this->spengine = spengine;
+	//this->gameconf = gameconf;
+
+	if (!CreateDetour())
+	{
+		enabled = false;
+		return enabled;
+	}
+
+	enabled = true;
+
+	return enabled;
+}
+
+void CDetour::Destroy()
+{
+	DeleteDetour();
+	delete this;
+}
+
+bool CDetour::IsEnabled()
+{
+	return enabled;
+}
+
+bool CDetour::CreateDetour()
+{
+	/*if (signame != NULL && !gameconf->GetMemSig(signame, &detour_address))
+	{
+		g_pSM->LogError(myself, "Could not locate %s - Disabling detour", signame);
+		return false;
+	}*/
+
+	if (address != NULL)
+	{
+		detour_address = address;
+	}
+
+	if (!detour_address)
+	{
+		//g_pSM->LogError(myself, "Sigscan for %s failed - Disabling detour to prevent crashes", signame);
+		return false;
+	}
+
+	detour_restore.bytes = copy_bytes((unsigned char *)detour_address, NULL, OP_JMP_SIZE+1);
+
+	/* First, save restore bits */
+	for (size_t i=0; i<detour_restore.bytes; i++)
+	{
+		detour_restore.patch[i] = ((unsigned char *)detour_address)[i];
+	}
+
+	JitWriter wr;
+	JitWriter *jit = &wr;
+	unsigned int CodeSize = 0;
+	
+	wr.outbase = NULL;
+	wr.outptr = NULL;
+
+jit_rewind:
+
+	/* Patch old bytes in */
+	if (wr.outbase != NULL)
+	{
+		copy_bytes((unsigned char *)detour_address, (unsigned char*)wr.outptr, detour_restore.bytes);
+	}
+	wr.outptr += detour_restore.bytes;
+
+	/* Return to the original function */
+	unsigned int call = IA32_Jump_Imm32(jit, 0);
+	IA32_Write_Jump32_Abs(jit, call, (unsigned char *)detour_address + detour_restore.bytes);
+
+	if (wr.outbase == NULL)
+	{
+		CodeSize = wr.get_outputpos();
+		wr.outbase = (char *)AllocatePageMemory(CodeSize);
+		//spengine->SetReadWrite(wr.outbase);
+		wr.outptr = wr.outbase;
+		detour_trampoline = wr.outbase;
+		goto jit_rewind;
+	}
+
+	//spengine->SetReadExecute(wr.outbase);
+
+	*trampoline = detour_trampoline;
+
+	return true;
+}
+
+void CDetour::DeleteDetour()
+{
+	if (detoured)
+	{
+		DisableDetour();
+	}
+
+	if (detour_trampoline)
+	{
+		/* Free the allocated trampoline memory */
+		FreePageMemory(detour_trampoline);
+		detour_trampoline = NULL;
+	}
+}
+
+void CDetour::EnableDetour()
+{
+	if (!detoured)
+	{
+		DoGatePatch((unsigned char *)detour_address, &detour_callback);
+		detoured = true;
+	}
+}
+
+void CDetour::DisableDetour()
+{
+	if (detoured)
+	{
+		/* Remove the patch */
+		ApplyPatch(detour_address, 0, &detour_restore, NULL);
+		detoured = false;
+	}
+}