125 lines
4.0 KiB
C++
125 lines
4.0 KiB
C++
/* Ham Sandwich
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* Copyright 2007
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* By the AMX Mod X Development Team
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*
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* Ham Sandwich is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at
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* your option) any later version.
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*
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* Ham Sandwich is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Ham Sandwich; if not, write to the Free Software Foundation,
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* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* In addition, as a special exception, the author gives permission to
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* link the code of Ham Sandwich with the Half-Life Game Engine ("HL
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* Engine") and Modified Game Libraries ("MODs") developed by Valve,
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* L.L.C ("Valve"). You must obey the GNU General Public License in all
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* respects for all of the code used other than the HL Engine and MODs
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* from Valve. If you modify this file, you may extend this exception
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* to your version of the file, but you are not obligated to do so. If
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* you do not wish to do so, delete this exception statement from your
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* version.
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*/
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#ifndef HOOK_H
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#define HOOK_H
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#include "forward.h"
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#include "Trampolines.h"
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// This is just a simple container for data so I only have to add 1 extra
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// parameter to calls that get trampolined
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#define ALIGN(ar) ((intptr_t)ar & ~(sysconf(_SC_PAGESIZE)-1))
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class Hook
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{
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public:
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CVector<Forward *> pre; // pre forwards
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CVector<Forward *> post; // post forwards
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void *func; // original function
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void **vtable; // vtable of the original location
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int entry; // vtable entry of the function
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void *target; // target function being called (the hook)
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int exec; // 1 when this hook is in execution
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int del; // 1 if this hook should be destroyed after exec
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void *tramp; // trampoline for this hook
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char *ent; // ent name that's being hooked
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Hook(void **vtable_, int entry_, void *target_, bool voidcall, int paramcount, char *name) :
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func(NULL), vtable(vtable_), entry(entry_), target(target_), exec(0), del(0), tramp(NULL)
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{
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// original function is vtable[entry]
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// to not make the compiler whine, cast vtable to int **
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int **ivtable=(int **)vtable;
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func=(void *)ivtable[entry];
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// now install a trampoline
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// (int thiscall, int voidcall, int paramcount, void *extraptr)
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tramp=CreateGenericTrampoline(true, voidcall, paramcount, (void*)this, target);
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// Insert into vtable
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#if defined _WIN32
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DWORD OldFlags;
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VirtualProtect(&ivtable[entry],sizeof(int*),PAGE_READWRITE,&OldFlags);
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#elif defined __linux__
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void *addr = (void *)ALIGN(&ivtable[entry]);
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mprotect(addr,sysconf(_SC_PAGESIZE),PROT_READ|PROT_WRITE);
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#endif
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ivtable[entry]=(int*)tramp;
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size_t len=strlen(name);
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ent=new char[len+1];
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snprintf(ent,len+1,"%s",name);
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};
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~Hook()
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{
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// Insert the original function back into the vtable
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int **ivtable=(int **)vtable;
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#if defined _WIN32
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DWORD OldFlags;
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VirtualProtect(&ivtable[entry],sizeof(int*),PAGE_READWRITE,&OldFlags);
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#elif defined __linux_
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void *addr = (void *)ALIGN(&ivtable[entry]);
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mprotect(addr,sysconf(_SC_PAGESIZE),PROT_READ|PROT_WRITE);
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#endif
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ivtable[entry]=(int *)func;
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#if defined _WIN32
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VirtualFree(tramp, 0, MEM_RELEASE);
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#elif __linux__
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free(tramp);
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#endif
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delete[] ent;
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CVector<Forward *>::iterator end=pre.end();
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for (CVector<Forward *>::iterator i=pre.begin();
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i!=end;
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++i)
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{
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delete (*i);
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}
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end=post.end();
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for (CVector<Forward *>::iterator i=post.begin();
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i!=end;
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++i)
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{
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delete (*i);
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}
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pre.clear();
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post.clear();
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}
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};
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#endif
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