mirror of
https://github.com/alliedmodders/amxmodx.git
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106 lines
3.0 KiB
C++
106 lines
3.0 KiB
C++
// vim: set ts=4 sw=4 tw=99 noet:
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//
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// AMX Mod X, based on AMX Mod by Aleksander Naszko ("OLO").
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// Copyright (C) The AMX Mod X Development Team.
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//
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// This software is licensed under the GNU General Public License, version 3 or higher.
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// Additional exceptions apply. For full license details, see LICENSE.txt or visit:
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// https://alliedmods.net/amxmodx-license
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//
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// Ham Sandwich Module
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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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#include <am-vector.h>
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#define ALIGN(ar) ((intptr_t)ar & ~(sysconf(_SC_PAGESIZE)-1))
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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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class Hook
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{
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public:
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ke::Vector<Forward *> pre; // pre forwards
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ke::Vector<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, bool retbuf, 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, retbuf, 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__) || defined(__APPLE__)
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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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UTIL_Format(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__) || defined(__APPLE__)
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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 defined(__linux__) || defined(__APPLE__)
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free(tramp);
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#endif
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delete[] ent;
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for (size_t i = 0; i < pre.length(); ++i)
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{
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pre.at(i)->Release();
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}
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for (size_t i = 0; i < post.length(); ++i)
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{
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post.at(i)->Release();
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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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