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minhook.inl
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/*
* MinHook - The Minimalistic API Hooking Library for x64/x86
* Copyright (c) 2009-2017 Tsuda Kageyu
* All rights reserved.
*
* Hacker Disassembler Engine 64 C
* Copyright (c) 2008-2009 Vyacheslav Patkov
* All rights reserved.
*
* Hacker Disassembler Engine 32 C
* Copyright (c) 2008-2009 Vyacheslav Patkov
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
* OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#if !(defined _M_IX86) && !(defined _M_X64) && !(defined __i386__) && !(defined __x86_64__)
#error MinHook supports only x86 and x64 systems.
#endif
#include <windows.h>
// MinHook Error Codes.
typedef enum MH_STATUS
{
// Unknown error. Should not be returned.
MH_UNKNOWN = -1,
// Successful.
MH_OK = 0,
// MinHook is already initialized.
MH_ERROR_ALREADY_INITIALIZED,
// MinHook is not initialized yet, or already uninitialized.
MH_ERROR_NOT_INITIALIZED,
// The hook for the specified target function is already created.
MH_ERROR_ALREADY_CREATED,
// The hook for the specified target function is not created yet.
MH_ERROR_NOT_CREATED,
// The hook for the specified target function is already enabled.
MH_ERROR_ENABLED,
// The hook for the specified target function is not enabled yet, or already
// disabled.
MH_ERROR_DISABLED,
// The specified pointer is invalid. It points the address of non-allocated
// and/or non-executable region.
MH_ERROR_NOT_EXECUTABLE,
// The specified target function cannot be hooked.
MH_ERROR_UNSUPPORTED_FUNCTION,
// Failed to allocate memory.
MH_ERROR_MEMORY_ALLOC,
// Failed to change the memory protection.
MH_ERROR_MEMORY_PROTECT,
// The specified module is not loaded.
MH_ERROR_MODULE_NOT_FOUND,
// The specified function is not found.
MH_ERROR_FUNCTION_NOT_FOUND
}
MH_STATUS;
// Can be passed as a parameter to MH_EnableHook, MH_DisableHook,
// MH_QueueEnableHook or MH_QueueDisableHook.
#define MH_ALL_HOOKS NULL
#ifdef __cplusplus
extern "C" {
#endif
// Initialize the MinHook library. You must call this function EXACTLY ONCE
// at the beginning of your program.
MH_STATUS WINAPI MH_Initialize(VOID);
// Uninitialize the MinHook library. You must call this function EXACTLY
// ONCE at the end of your program.
MH_STATUS WINAPI MH_Uninitialize(VOID);
// Creates a hook for the specified target function, in disabled state.
// Parameters:
// pTarget [in] A pointer to the target function, which will be
// overridden by the detour function.
// pDetour [in] A pointer to the detour function, which will override
// the target function.
// ppOriginal [out] A pointer to the trampoline function, which will be
// used to call the original target function.
// This parameter can be NULL.
MH_STATUS WINAPI MH_CreateHook(LPVOID pTarget, LPVOID pDetour, LPVOID *ppOriginal);
// Creates a hook for the specified API function, in disabled state.
// Parameters:
// pszModule [in] A pointer to the loaded module name which contains the
// target function.
// pszProcName [in] A pointer to the target function name, which will be
// overridden by the detour function.
// pDetour [in] A pointer to the detour function, which will override
// the target function.
// ppOriginal [out] A pointer to the trampoline function, which will be
// used to call the original target function.
// This parameter can be NULL.
MH_STATUS WINAPI MH_CreateHookApi(
LPCWSTR pszModule, LPCSTR pszProcName, LPVOID pDetour, LPVOID *ppOriginal);
// Creates a hook for the specified API function, in disabled state.
// Parameters:
// pszModule [in] A pointer to the loaded module name which contains the
// target function.
// pszProcName [in] A pointer to the target function name, which will be
// overridden by the detour function.
// pDetour [in] A pointer to the detour function, which will override
// the target function.
// ppOriginal [out] A pointer to the trampoline function, which will be
// used to call the original target function.
// This parameter can be NULL.
// ppTarget [out] A pointer to the target function, which will be used
// with other functions.
// This parameter can be NULL.
MH_STATUS WINAPI MH_CreateHookApiEx(
LPCWSTR pszModule, LPCSTR pszProcName, LPVOID pDetour, LPVOID *ppOriginal, LPVOID *ppTarget);
// Removes an already created hook.
// Parameters:
// pTarget [in] A pointer to the target function.
MH_STATUS WINAPI MH_RemoveHook(LPVOID pTarget);
// Enables an already created hook.
// Parameters:
// pTarget [in] A pointer to the target function.
// If this parameter is MH_ALL_HOOKS, all created hooks are
// enabled in one go.
MH_STATUS WINAPI MH_EnableHook(LPVOID pTarget);
// Disables an already created hook.
// Parameters:
// pTarget [in] A pointer to the target function.
// If this parameter is MH_ALL_HOOKS, all created hooks are
// disabled in one go.
MH_STATUS WINAPI MH_DisableHook(LPVOID pTarget);
// Queues to enable an already created hook.
// Parameters:
// pTarget [in] A pointer to the target function.
// If this parameter is MH_ALL_HOOKS, all created hooks are
// queued to be enabled.
MH_STATUS WINAPI MH_QueueEnableHook(LPVOID pTarget);
// Queues to disable an already created hook.
// Parameters:
// pTarget [in] A pointer to the target function.
// If this parameter is MH_ALL_HOOKS, all created hooks are
// queued to be disabled.
MH_STATUS WINAPI MH_QueueDisableHook(LPVOID pTarget);
// Applies all queued changes in one go.
MH_STATUS WINAPI MH_ApplyQueued(VOID);
// Translates the MH_STATUS to its name as a string.
const char * WINAPI MH_StatusToString(MH_STATUS status);
#ifndef MINHOOK_NO_IMPLEMENTATION
#include <tlhelp32.h>
#include <limits.h>
#include <string.h>
#ifdef _MSC_VER
#include <intrin.h>
#endif
// Size of each memory slot.
#if defined(_M_X64) || defined(__x86_64__)
#define MEMORY_SLOT_SIZE 64
#else
#define MEMORY_SLOT_SIZE 32
#endif
VOID InitializeBuffer(VOID);
VOID UninitializeBuffer(VOID);
LPVOID AllocateBuffer(LPVOID pOrigin);
VOID FreeBuffer(LPVOID pBuffer);
BOOL IsExecutableAddress(LPVOID pAddress);
#pragma pack(push, 1)
// Structs for writing x86/x64 instructions.
// 8-bit relative jump.
typedef struct _JMP_REL_SHORT
{
UINT8 opcode; // EB xx: JMP +2+xx
UINT8 operand;
} JMP_REL_SHORT, *PJMP_REL_SHORT;
// 32-bit direct relative jump/call.
typedef struct _JMP_REL
{
UINT8 opcode; // E9/E8 xxxxxxxx: JMP/CALL +5+xxxxxxxx
UINT32 operand; // Relative destination address
} JMP_REL, *PJMP_REL, CALL_REL;
// 64-bit indirect absolute jump.
typedef struct _JMP_ABS
{
UINT8 opcode0; // FF25 00000000: JMP [+6]
UINT8 opcode1;
UINT32 dummy;
UINT64 address; // Absolute destination address
} JMP_ABS, *PJMP_ABS;
// 64-bit indirect absolute call.
typedef struct _CALL_ABS
{
UINT8 opcode0; // FF15 00000002: CALL [+6]
UINT8 opcode1;
UINT32 dummy0;
UINT8 dummy1; // EB 08: JMP +10
UINT8 dummy2;
UINT64 address; // Absolute destination address
} CALL_ABS;
// 32-bit direct relative conditional jumps.
typedef struct _JCC_REL
{
UINT8 opcode0; // 0F8* xxxxxxxx: J** +6+xxxxxxxx
UINT8 opcode1;
UINT32 operand; // Relative destination address
} JCC_REL;
// 64bit indirect absolute conditional jumps that x64 lacks.
typedef struct _JCC_ABS
{
UINT8 opcode; // 7* 0E: J** +16
UINT8 dummy0;
UINT8 dummy1; // FF25 00000000: JMP [+6]
UINT8 dummy2;
UINT32 dummy3;
UINT64 address; // Absolute destination address
} JCC_ABS;
#pragma pack(pop)
typedef struct _TRAMPOLINE
{
LPVOID pTarget; // [In] Address of the target function.
LPVOID pDetour; // [In] Address of the detour function.
LPVOID pTrampoline; // [In] Buffer address for the trampoline and relay function.
#if defined(_M_X64) || defined(__x86_64__)
LPVOID pRelay; // [Out] Address of the relay function.
#endif
BOOL patchAbove; // [Out] Should use the hot patch area?
UINT nIP; // [Out] Number of the instruction boundaries.
UINT8 oldIPs[8]; // [Out] Instruction boundaries of the target function.
UINT8 newIPs[8]; // [Out] Instruction boundaries of the trampoline function.
} TRAMPOLINE, *PTRAMPOLINE;
BOOL CreateTrampolineFunction(PTRAMPOLINE ct);
// Integer types for HDE.
typedef INT8 int8_t;
typedef INT16 int16_t;
typedef INT32 int32_t;
typedef INT64 int64_t;
typedef UINT8 uint8_t;
typedef UINT16 uint16_t;
typedef UINT32 uint32_t;
typedef UINT64 uint64_t;
/*
* Hacker Disassembler Engine 32
* Copyright (c) 2008-2009, Vyacheslav Patkov.
* All rights reserved.
*
*/
#if defined(_M_IX86) || defined(__i386__)
#define F_MODRM 0x00000001
#define F_SIB 0x00000002
#define F_IMM8 0x00000004
#define F_IMM16 0x00000008
#define F_IMM32 0x00000010
#define F_DISP8 0x00000020
#define F_DISP16 0x00000040
#define F_DISP32 0x00000080
#define F_RELATIVE 0x00000100
#define F_2IMM16 0x00000800
#define F_ERROR 0x00001000
#define F_ERROR_OPCODE 0x00002000
#define F_ERROR_LENGTH 0x00004000
#define F_ERROR_LOCK 0x00008000
#define F_ERROR_OPERAND 0x00010000
#define F_PREFIX_REPNZ 0x01000000
#define F_PREFIX_REPX 0x02000000
#define F_PREFIX_REP 0x03000000
#define F_PREFIX_66 0x04000000
#define F_PREFIX_67 0x08000000
#define F_PREFIX_LOCK 0x10000000
#define F_PREFIX_SEG 0x20000000
#define F_PREFIX_ANY 0x3f000000
#define PREFIX_SEGMENT_CS 0x2e
#define PREFIX_SEGMENT_SS 0x36
#define PREFIX_SEGMENT_DS 0x3e
#define PREFIX_SEGMENT_ES 0x26
#define PREFIX_SEGMENT_FS 0x64
#define PREFIX_SEGMENT_GS 0x65
#define PREFIX_LOCK 0xf0
#define PREFIX_REPNZ 0xf2
#define PREFIX_REPX 0xf3
#define PREFIX_OPERAND_SIZE 0x66
#define PREFIX_ADDRESS_SIZE 0x67
#pragma pack(push,1)
typedef struct {
uint8_t len;
uint8_t p_rep;
uint8_t p_lock;
uint8_t p_seg;
uint8_t p_66;
uint8_t p_67;
uint8_t opcode;
uint8_t opcode2;
uint8_t modrm;
uint8_t modrm_mod;
uint8_t modrm_reg;
uint8_t modrm_rm;
uint8_t sib;
uint8_t sib_scale;
uint8_t sib_index;
uint8_t sib_base;
union {
uint8_t imm8;
uint16_t imm16;
uint32_t imm32;
} imm;
union {
uint8_t disp8;
uint16_t disp16;
uint32_t disp32;
} disp;
uint32_t flags;
} hde32s;
#pragma pack(pop)
/* __cdecl */
unsigned int hde32_disasm(const void *code, hde32s *hs);
#endif // defined(_M_IX86) || defined(__i386__)
/*
* Hacker Disassembler Engine 64
* Copyright (c) 2008-2009, Vyacheslav Patkov.
* All rights reserved.
*
*/
#if defined(_M_X64) || defined(__x86_64__)
#define F_MODRM 0x00000001
#define F_SIB 0x00000002
#define F_IMM8 0x00000004
#define F_IMM16 0x00000008
#define F_IMM32 0x00000010
#define F_IMM64 0x00000020
#define F_DISP8 0x00000040
#define F_DISP16 0x00000080
#define F_DISP32 0x00000100
#define F_RELATIVE 0x00000200
#define F_ERROR 0x00001000
#define F_ERROR_OPCODE 0x00002000
#define F_ERROR_LENGTH 0x00004000
#define F_ERROR_LOCK 0x00008000
#define F_ERROR_OPERAND 0x00010000
#define F_PREFIX_REPNZ 0x01000000
#define F_PREFIX_REPX 0x02000000
#define F_PREFIX_REP 0x03000000
#define F_PREFIX_66 0x04000000
#define F_PREFIX_67 0x08000000
#define F_PREFIX_LOCK 0x10000000
#define F_PREFIX_SEG 0x20000000
#define F_PREFIX_REX 0x40000000
#define F_PREFIX_ANY 0x7f000000
#define PREFIX_SEGMENT_CS 0x2e
#define PREFIX_SEGMENT_SS 0x36
#define PREFIX_SEGMENT_DS 0x3e
#define PREFIX_SEGMENT_ES 0x26
#define PREFIX_SEGMENT_FS 0x64
#define PREFIX_SEGMENT_GS 0x65
#define PREFIX_LOCK 0xf0
#define PREFIX_REPNZ 0xf2
#define PREFIX_REPX 0xf3
#define PREFIX_OPERAND_SIZE 0x66
#define PREFIX_ADDRESS_SIZE 0x67
#pragma pack(push,1)
typedef struct {
uint8_t len;
uint8_t p_rep;
uint8_t p_lock;
uint8_t p_seg;
uint8_t p_66;
uint8_t p_67;
uint8_t rex;
uint8_t rex_w;
uint8_t rex_r;
uint8_t rex_x;
uint8_t rex_b;
uint8_t opcode;
uint8_t opcode2;
uint8_t modrm;
uint8_t modrm_mod;
uint8_t modrm_reg;
uint8_t modrm_rm;
uint8_t sib;
uint8_t sib_scale;
uint8_t sib_index;
uint8_t sib_base;
union {
uint8_t imm8;
uint16_t imm16;
uint32_t imm32;
uint64_t imm64;
} imm;
union {
uint8_t disp8;
uint16_t disp16;
uint32_t disp32;
} disp;
uint32_t flags;
} hde64s;
#pragma pack(pop)
/* __cdecl */
unsigned int hde64_disasm(const void *code, hde64s *hs);
#endif // defined(_M_X64) || defined(__x86_64__)
#ifndef ARRAYSIZE
#define ARRAYSIZE(A) (sizeof(A)/sizeof((A)[0]))
#endif
// Initial capacity of the HOOK_ENTRY buffer.
#define INITIAL_HOOK_CAPACITY 32
// Initial capacity of the thread IDs buffer.
#define INITIAL_THREAD_CAPACITY 128
// Special hook position values.
#define INVALID_HOOK_POS UINT_MAX
#define ALL_HOOKS_POS UINT_MAX
// Freeze() action argument defines.
#define ACTION_DISABLE 0
#define ACTION_ENABLE 1
#define ACTION_APPLY_QUEUED 2
// Thread access rights for suspending/resuming threads.
#define THREAD_ACCESS \
(THREAD_SUSPEND_RESUME | THREAD_GET_CONTEXT | THREAD_QUERY_INFORMATION | THREAD_SET_CONTEXT)
// Hook information.
typedef struct _HOOK_ENTRY
{
LPVOID pTarget; // Address of the target function.
LPVOID pDetour; // Address of the detour or relay function.
LPVOID pTrampoline; // Address of the trampoline function.
UINT8 backup[8]; // Original prologue of the target function.
UINT8 patchAbove : 1; // Uses the hot patch area.
UINT8 isEnabled : 1; // Enabled.
UINT8 queueEnable : 1; // Queued for enabling/disabling when != isEnabled.
UINT nIP : 4; // Count of the instruction boundaries.
UINT8 oldIPs[8]; // Instruction boundaries of the target function.
UINT8 newIPs[8]; // Instruction boundaries of the trampoline function.
} HOOK_ENTRY, *PHOOK_ENTRY;
// Suspended threads for Freeze()/Unfreeze().
typedef struct _FROZEN_THREADS
{
LPDWORD pItems; // Data heap
UINT capacity; // Size of allocated data heap, items
UINT size; // Actual number of data items
} FROZEN_THREADS, *PFROZEN_THREADS;
//-------------------------------------------------------------------------
// Global Variables:
//-------------------------------------------------------------------------
// Spin lock flag for EnterSpinLock()/LeaveSpinLock().
volatile LONG g_isLocked = FALSE;
// Private heap handle. If not NULL, this library is initialized.
HANDLE g_hHeap = NULL;
// Hook entries.
struct
{
PHOOK_ENTRY pItems; // Data heap
UINT capacity; // Size of allocated data heap, items
UINT size; // Actual number of data items
} g_hooks;
//-------------------------------------------------------------------------
// Returns INVALID_HOOK_POS if not found.
static UINT FindHookEntry(LPVOID pTarget)
{
UINT i;
for (i = 0; i < g_hooks.size; ++i)
{
if ((ULONG_PTR)pTarget == (ULONG_PTR)g_hooks.pItems[i].pTarget)
return i;
}
return INVALID_HOOK_POS;
}
//-------------------------------------------------------------------------
static PHOOK_ENTRY AddHookEntry()
{
if (g_hooks.pItems == NULL)
{
g_hooks.capacity = INITIAL_HOOK_CAPACITY;
g_hooks.pItems = (PHOOK_ENTRY)HeapAlloc(
g_hHeap, 0, g_hooks.capacity * sizeof(HOOK_ENTRY));
if (g_hooks.pItems == NULL)
return NULL;
}
else if (g_hooks.size >= g_hooks.capacity)
{
PHOOK_ENTRY p = (PHOOK_ENTRY)HeapReAlloc(
g_hHeap, 0, g_hooks.pItems, (g_hooks.capacity * 2) * sizeof(HOOK_ENTRY));
if (p == NULL)
return NULL;
g_hooks.capacity *= 2;
g_hooks.pItems = p;
}
return &g_hooks.pItems[g_hooks.size++];
}
//-------------------------------------------------------------------------
static void DeleteHookEntry(UINT pos)
{
if (pos < g_hooks.size - 1)
g_hooks.pItems[pos] = g_hooks.pItems[g_hooks.size - 1];
g_hooks.size--;
if (g_hooks.capacity / 2 >= INITIAL_HOOK_CAPACITY && g_hooks.capacity / 2 >= g_hooks.size)
{
PHOOK_ENTRY p = (PHOOK_ENTRY)HeapReAlloc(
g_hHeap, 0, g_hooks.pItems, (g_hooks.capacity / 2) * sizeof(HOOK_ENTRY));
if (p == NULL)
return;
g_hooks.capacity /= 2;
g_hooks.pItems = p;
}
}
//-------------------------------------------------------------------------
static DWORD_PTR FindOldIP(PHOOK_ENTRY pHook, DWORD_PTR ip)
{
UINT i;
if (pHook->patchAbove && ip == ((DWORD_PTR)pHook->pTarget - sizeof(JMP_REL)))
return (DWORD_PTR)pHook->pTarget;
for (i = 0; i < pHook->nIP; ++i)
{
if (ip == ((DWORD_PTR)pHook->pTrampoline + pHook->newIPs[i]))
return (DWORD_PTR)pHook->pTarget + pHook->oldIPs[i];
}
#if defined(_M_X64) || defined(__x86_64__)
// Check relay function.
if (ip == (DWORD_PTR)pHook->pDetour)
return (DWORD_PTR)pHook->pTarget;
#endif
return 0;
}
//-------------------------------------------------------------------------
static DWORD_PTR FindNewIP(PHOOK_ENTRY pHook, DWORD_PTR ip)
{
UINT i;
for (i = 0; i < pHook->nIP; ++i)
{
if (ip == ((DWORD_PTR)pHook->pTarget + pHook->oldIPs[i]))
return (DWORD_PTR)pHook->pTrampoline + pHook->newIPs[i];
}
return 0;
}
//-------------------------------------------------------------------------
static void ProcessThreadIPs(HANDLE hThread, UINT pos, UINT action)
{
// If the thread suspended in the overwritten area,
// move IP to the proper address.
CONTEXT c;
#if defined(_M_X64) || defined(__x86_64__)
DWORD64 *pIP = &c.Rip;
#else
DWORD *pIP = &c.Eip;
#endif
UINT count;
c.ContextFlags = CONTEXT_CONTROL;
if (!GetThreadContext(hThread, &c))
return;
if (pos == ALL_HOOKS_POS)
{
pos = 0;
count = g_hooks.size;
}
else
{
count = pos + 1;
}
for (; pos < count; ++pos)
{
PHOOK_ENTRY pHook = &g_hooks.pItems[pos];
BOOL enable;
DWORD_PTR ip;
switch (action)
{
case ACTION_DISABLE:
enable = FALSE;
break;
case ACTION_ENABLE:
enable = TRUE;
break;
default: // ACTION_APPLY_QUEUED
enable = pHook->queueEnable;
break;
}
if (pHook->isEnabled == enable)
continue;
if (enable)
ip = FindNewIP(pHook, *pIP);
else
ip = FindOldIP(pHook, *pIP);
if (ip != 0)
{
*pIP = ip;
SetThreadContext(hThread, &c);
}
}
}
//-------------------------------------------------------------------------
static VOID EnumerateThreads(PFROZEN_THREADS pThreads)
{
HANDLE hSnapshot = CreateToolhelp32Snapshot(TH32CS_SNAPTHREAD, 0);
if (hSnapshot != INVALID_HANDLE_VALUE)
{
THREADENTRY32 te;
te.dwSize = sizeof(THREADENTRY32);
if (Thread32First(hSnapshot, &te))
{
do
{
if (te.dwSize >= (FIELD_OFFSET(THREADENTRY32, th32OwnerProcessID) + sizeof(DWORD))
&& te.th32OwnerProcessID == GetCurrentProcessId()
&& te.th32ThreadID != GetCurrentThreadId())
{
if (pThreads->pItems == NULL)
{
pThreads->capacity = INITIAL_THREAD_CAPACITY;
pThreads->pItems
= (LPDWORD)HeapAlloc(g_hHeap, 0, pThreads->capacity * sizeof(DWORD));
if (pThreads->pItems == NULL)
break;
}
else if (pThreads->size >= pThreads->capacity)
{
LPDWORD p = (LPDWORD)HeapReAlloc(
g_hHeap, 0, pThreads->pItems, (pThreads->capacity * 2) * sizeof(DWORD));
if (p == NULL)
break;
pThreads->capacity *= 2;
pThreads->pItems = p;
}
pThreads->pItems[pThreads->size++] = te.th32ThreadID;
}
te.dwSize = sizeof(THREADENTRY32);
} while (Thread32Next(hSnapshot, &te));
}
CloseHandle(hSnapshot);
}
}
//-------------------------------------------------------------------------
static VOID Freeze(PFROZEN_THREADS pThreads, UINT pos, UINT action)
{
pThreads->pItems = NULL;
pThreads->capacity = 0;
pThreads->size = 0;
EnumerateThreads(pThreads);
if (pThreads->pItems != NULL)
{
UINT i;
for (i = 0; i < pThreads->size; ++i)
{
HANDLE hThread = OpenThread(THREAD_ACCESS, FALSE, pThreads->pItems[i]);
if (hThread != NULL)
{
SuspendThread(hThread);
ProcessThreadIPs(hThread, pos, action);
CloseHandle(hThread);
}
}
}
}
//-------------------------------------------------------------------------
static VOID Unfreeze(PFROZEN_THREADS pThreads)
{
if (pThreads->pItems != NULL)
{
UINT i;
for (i = 0; i < pThreads->size; ++i)
{
HANDLE hThread = OpenThread(THREAD_ACCESS, FALSE, pThreads->pItems[i]);
if (hThread != NULL)
{
ResumeThread(hThread);
CloseHandle(hThread);
}
}
HeapFree(g_hHeap, 0, pThreads->pItems);
}
}
//-------------------------------------------------------------------------
static MH_STATUS EnableHookLL(UINT pos, BOOL enable)
{
PHOOK_ENTRY pHook = &g_hooks.pItems[pos];
DWORD oldProtect;
SIZE_T patchSize = sizeof(JMP_REL);
LPBYTE pPatchTarget = (LPBYTE)pHook->pTarget;
if (pHook->patchAbove)
{
pPatchTarget -= sizeof(JMP_REL);
patchSize += sizeof(JMP_REL_SHORT);
}
if (!VirtualProtect(pPatchTarget, patchSize, PAGE_EXECUTE_READWRITE, &oldProtect))
return MH_ERROR_MEMORY_PROTECT;
if (enable)
{
PJMP_REL pJmp = (PJMP_REL)pPatchTarget;
pJmp->opcode = 0xE9;
pJmp->operand = (UINT32)((LPBYTE)pHook->pDetour - (pPatchTarget + sizeof(JMP_REL)));
if (pHook->patchAbove)
{
PJMP_REL_SHORT pShortJmp = (PJMP_REL_SHORT)pHook->pTarget;
pShortJmp->opcode = 0xEB;
pShortJmp->operand = (UINT8)(0 - (sizeof(JMP_REL_SHORT) + sizeof(JMP_REL)));
}
}
else
{
if (pHook->patchAbove)
memcpy(pPatchTarget, pHook->backup, sizeof(JMP_REL) + sizeof(JMP_REL_SHORT));
else
memcpy(pPatchTarget, pHook->backup, sizeof(JMP_REL));
}
VirtualProtect(pPatchTarget, patchSize, oldProtect, &oldProtect);
// Just-in-case measure.
FlushInstructionCache(GetCurrentProcess(), pPatchTarget, patchSize);
pHook->isEnabled = enable;
pHook->queueEnable = enable;
return MH_OK;
}
//-------------------------------------------------------------------------
static MH_STATUS EnableAllHooksLL(BOOL enable)
{
MH_STATUS status = MH_OK;
UINT i, first = INVALID_HOOK_POS;
for (i = 0; i < g_hooks.size; ++i)
{
if (g_hooks.pItems[i].isEnabled != enable)
{
first = i;
break;
}
}
if (first != INVALID_HOOK_POS)
{
FROZEN_THREADS threads;
Freeze(&threads, ALL_HOOKS_POS, enable ? ACTION_ENABLE : ACTION_DISABLE);
for (i = first; i < g_hooks.size; ++i)
{
if (g_hooks.pItems[i].isEnabled != enable)
{
status = EnableHookLL(i, enable);
if (status != MH_OK)
break;
}
}
Unfreeze(&threads);
}
return status;
}
//-------------------------------------------------------------------------
static VOID EnterSpinLock(VOID)
{
SIZE_T spinCount = 0;
// Wait until the flag is FALSE.
while (InterlockedCompareExchange(&g_isLocked, TRUE, FALSE) != FALSE)
{
// No need to generate a memory barrier here, since InterlockedCompareExchange()
// generates a full memory barrier itself.
// Prevent the loop from being too busy.
if (spinCount < 32)
Sleep(0);
else
Sleep(1);
spinCount++;
}
}
//-------------------------------------------------------------------------
static VOID LeaveSpinLock(VOID)
{
// No need to generate a memory barrier here, since InterlockedExchange()
// generates a full memory barrier itself.
InterlockedExchange(&g_isLocked, FALSE);
}
//-------------------------------------------------------------------------
MH_STATUS WINAPI MH_Initialize(VOID)
{
MH_STATUS status = MH_OK;
EnterSpinLock();
if (g_hHeap == NULL)
{
g_hHeap = HeapCreate(0, 0, 0);
if (g_hHeap != NULL)
{
// Initialize the internal function buffer.
InitializeBuffer();
}
else
{
status = MH_ERROR_MEMORY_ALLOC;
}
}
else
{
status = MH_ERROR_ALREADY_INITIALIZED;
}
LeaveSpinLock();
return status;
}
//-------------------------------------------------------------------------
MH_STATUS WINAPI MH_Uninitialize(VOID)
{
MH_STATUS status = MH_OK;
EnterSpinLock();
if (g_hHeap != NULL)
{
status = EnableAllHooksLL(FALSE);
if (status == MH_OK)
{
// Free the internal function buffer.
// HeapFree is actually not required, but some tools detect a false
// memory leak without HeapFree.
UninitializeBuffer();
HeapFree(g_hHeap, 0, g_hooks.pItems);
HeapDestroy(g_hHeap);
g_hHeap = NULL;
g_hooks.pItems = NULL;
g_hooks.capacity = 0;
g_hooks.size = 0;
}
}
else
{
status = MH_ERROR_NOT_INITIALIZED;
}
LeaveSpinLock();
return status;
}
//-------------------------------------------------------------------------
MH_STATUS WINAPI MH_CreateHook(LPVOID pTarget, LPVOID pDetour, LPVOID *ppOriginal)
{
MH_STATUS status = MH_OK;
EnterSpinLock();
if (g_hHeap != NULL)
{
if (IsExecutableAddress(pTarget) && IsExecutableAddress(pDetour))
{
UINT pos = FindHookEntry(pTarget);
if (pos == INVALID_HOOK_POS)
{
LPVOID pBuffer = AllocateBuffer(pTarget);
if (pBuffer != NULL)
{
TRAMPOLINE ct;
ct.pTarget = pTarget;
ct.pDetour = pDetour;
ct.pTrampoline = pBuffer;
if (CreateTrampolineFunction(&ct))
{
PHOOK_ENTRY pHook = AddHookEntry();
if (pHook != NULL)
{
pHook->pTarget = ct.pTarget;
#if defined(_M_X64) || defined(__x86_64__)
pHook->pDetour = ct.pRelay;
#else
pHook->pDetour = ct.pDetour;