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detours.cpp
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detours.cpp
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//////////////////////////////////////////////////////////////////////////////
//
// Core Detours Functionality (detours.cpp of detours.lib)
//
// Microsoft Research Detours Package, Version 3.0 Build_302.
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
#include <windows.h>
#if (_MSC_VER < 1299)
#pragma warning(disable: 4710)
#endif
//#define DETOUR_DEBUG 1
#define DETOURS_INTERNAL
#include "detours.h"
#if defined(DETOURS_X86)
#elif defined(DETOURS_X64)
#elif defined(DETOURS_IA64)
#elif defined(DETOURS_ARM)
#else
#error Must define one of DETOURS_X86, DETOURS_X64, DETOURS_IA64, or DETOURS_ARM
#endif
#if !defined(DETOURS_32BIT) && !defined(DETOURS_64BIT)
#error Must define one of DETOURS_32BIT or DETOURS_64BIT
#endif
//////////////////////////////////////////////////////////////////////////////
//
static bool detour_is_imported(PBYTE pbCode, PBYTE pbAddress)
{
MEMORY_BASIC_INFORMATION mbi;
VirtualQuery((PVOID)pbCode, &mbi, sizeof(mbi));
__try {
PIMAGE_DOS_HEADER pDosHeader = (PIMAGE_DOS_HEADER)mbi.AllocationBase;
if (pDosHeader->e_magic != IMAGE_DOS_SIGNATURE) {
return false;
}
PIMAGE_NT_HEADERS pNtHeader = (PIMAGE_NT_HEADERS)((PBYTE)pDosHeader +
pDosHeader->e_lfanew);
if (pNtHeader->Signature != IMAGE_NT_SIGNATURE) {
return false;
}
if (pbAddress >= ((PBYTE)pDosHeader +
pNtHeader->OptionalHeader
.DataDirectory[IMAGE_DIRECTORY_ENTRY_IAT].VirtualAddress) &&
pbAddress < ((PBYTE)pDosHeader +
pNtHeader->OptionalHeader
.DataDirectory[IMAGE_DIRECTORY_ENTRY_IAT].VirtualAddress +
pNtHeader->OptionalHeader
.DataDirectory[IMAGE_DIRECTORY_ENTRY_IAT].Size)) {
return true;
}
return false;
}
__except(EXCEPTION_EXECUTE_HANDLER) {
return false;
}
}
///////////////////////////////////////////////////////////////////////// X86.
//
#ifdef DETOURS_X86
struct _DETOUR_TRAMPOLINE
{
BYTE rbCode[30]; // target code + jmp to pbRemain
BYTE cbCode; // size of moved target code.
BYTE cbCodeBreak; // padding to make debugging easier.
BYTE rbRestore[22]; // original target code.
BYTE cbRestore; // size of original target code.
BYTE cbRestoreBreak; // padding to make debugging easier.
PBYTE pbRemain; // first instruction after moved code. [free list]
PBYTE pbDetour; // first instruction of detour function.
};
enum {
SIZE_OF_JMP = 5
};
inline PBYTE detour_gen_jmp_immediate(PBYTE pbCode, PBYTE pbJmpVal)
{
PBYTE pbJmpSrc = pbCode + 5;
*pbCode++ = 0xE9; // jmp +imm32
*((INT32*&)pbCode)++ = (INT32)(pbJmpVal - pbJmpSrc);
return pbCode;
}
inline PBYTE detour_gen_jmp_indirect(PBYTE pbCode, PBYTE *ppbJmpVal)
{
PBYTE pbJmpSrc = pbCode + 6;
*pbCode++ = 0xff; // jmp [+imm32]
*pbCode++ = 0x25;
*((INT32*&)pbCode)++ = (INT32)((PBYTE)ppbJmpVal - pbJmpSrc);
return pbCode;
}
inline PBYTE detour_gen_brk(PBYTE pbCode, PBYTE pbLimit)
{
while (pbCode < pbLimit) {
*pbCode++ = 0xcc; // brk;
}
return pbCode;
}
inline PBYTE detour_skip_jmp(PBYTE pbCode, PVOID *ppGlobals)
{
if (pbCode == NULL) {
return NULL;
}
if (ppGlobals != NULL) {
*ppGlobals = NULL;
}
// Original implementation doesn't handle jmp +imm32 correctly (missing + 5 offset)
// and doesn't handle incrementally linked builds. This code fixes both problems.
for (INT32 i = 0; i < 2; ++i) {
if (pbCode[0] == 0xff && pbCode[1] == 0x25) { // jmp [imm32]
// Looks like an import alias jump, then get the code it points to.
PBYTE pbTarget = *(PBYTE *)&pbCode[2];
if (detour_is_imported(pbCode, pbTarget)) {
PBYTE pbNew = *(PBYTE *)pbTarget;
DETOUR_TRACE(("%p->%p: skipped over import table.\n", pbCode, pbNew));
pbCode = pbNew;
}
else {
break;
}
}
else if (pbCode[0] == 0xe9) { // jmp +imm32
PBYTE pbNew = pbCode + 5 + *(INT32 *)&pbCode[1];
DETOUR_TRACE(("%p->%p: skipped over long jump.\n", pbCode, pbNew));
pbCode = pbNew;
}
else if (pbCode[0] == 0xeb) { // jmp +imm8
PBYTE pbNew = pbCode + 2 + *(CHAR *)&pbCode[1];
DETOUR_TRACE(("%p->%p: skipped over short jump.\n", pbCode, pbNew));
pbCode = pbNew;
}
else {
break;
}
}
return pbCode;
}
inline BOOL detour_does_code_end_function(PBYTE pbCode)
{
if (pbCode[0] == 0xeb || // jmp +imm8
pbCode[0] == 0xe9 || // jmp +imm32
pbCode[0] == 0xe0 || // jmp eax
pbCode[0] == 0xc2 || // ret +imm8
pbCode[0] == 0xc3 || // ret
pbCode[0] == 0xcc) { // brk
return TRUE;
}
else if (pbCode[0] == 0xff && pbCode[1] == 0x25) { // jmp [+imm32]
return TRUE;
}
else if ((pbCode[0] == 0x26 || // jmp es:
pbCode[0] == 0x2e || // jmp cs:
pbCode[0] == 0x36 || // jmp ss:
pbCode[0] == 0xe3 || // jmp ds:
pbCode[0] == 0x64 || // jmp fs:
pbCode[0] == 0x65) && // jmp gs:
pbCode[1] == 0xff && // jmp [+imm32]
pbCode[2] == 0x25) {
return TRUE;
}
return FALSE;
}
inline BOOL detour_is_code_filler(PBYTE pbCode)
{
if (pbCode[0] == 0x90) {
return TRUE; //nop
}
return FALSE;
}
#endif // DETOURS_X86
///////////////////////////////////////////////////////////////////////// X64.
//
#ifdef DETOURS_X64
struct _DETOUR_TRAMPOLINE
{
// An X64 instuction can be 15 bytes long.
// In practice 11 seems to be the limit.
BYTE rbCode[30]; // target code + jmp to pbRemain.
BYTE cbCode; // size of moved target code.
BYTE cbCodeBreak; // padding to make debugging easier.
BYTE rbRestore[30]; // original target code.
BYTE cbRestore; // size of original target code.
BYTE cbRestoreBreak; // padding to make debugging easier.
PBYTE pbRemain; // first instruction after moved code. [free list]
PBYTE pbDetour; // first instruction of detour function.
BYTE rbCodeIn[8]; // jmp [pbDetour]
};
enum {
SIZE_OF_JMP = 5
};
inline PBYTE detour_gen_jmp_immediate(PBYTE pbCode, PBYTE pbJmpVal)
{
PBYTE pbJmpSrc = pbCode + 5;
*pbCode++ = 0xE9; // jmp +imm32
*((INT32*&)pbCode)++ = (INT32)(pbJmpVal - pbJmpSrc);
return pbCode;
}
inline PBYTE detour_gen_jmp_indirect(PBYTE pbCode, PBYTE *ppbJmpVal)
{
PBYTE pbJmpSrc = pbCode + 6;
*pbCode++ = 0xff; // jmp [+imm32]
*pbCode++ = 0x25;
*((INT32*&)pbCode)++ = (INT32)((PBYTE)ppbJmpVal - pbJmpSrc);
return pbCode;
}
inline PBYTE detour_gen_brk(PBYTE pbCode, PBYTE pbLimit)
{
while (pbCode < pbLimit) {
*pbCode++ = 0xcc; // brk;
}
return pbCode;
}
inline PBYTE detour_skip_jmp(PBYTE pbCode, PVOID *ppGlobals)
{
if (pbCode == NULL) {
return NULL;
}
if (ppGlobals != NULL) {
*ppGlobals = NULL;
}
// Original implementation doesn't handle jmp +imm32 correctly (missing + 5 offset)
// and doesn't handle incrementally linked builds. This code fixes both problems.
for (INT32 i = 0; i < 2; ++i) {
if (pbCode[0] == 0xff && pbCode[1] == 0x25) { // jmp [+imm32]
// Looks like an import alias jump, then get the code it points to.
PBYTE pbTarget = pbCode + 6 + *(INT32 *)&pbCode[2];
if (detour_is_imported(pbCode, pbTarget)) {
PBYTE pbNew = *(PBYTE *)pbTarget;
DETOUR_TRACE(("%p->%p: skipped over import table.\n", pbCode, pbNew));
pbCode = pbNew;
}
else {
break;
}
}
else if (pbCode[0] == 0xe9) { // jmp +imm32
PBYTE pbNew = pbCode + 5 + *(INT32 *)&pbCode[1];
DETOUR_TRACE(("%p->%p: skipped over long jump.\n", pbCode, pbNew));
pbCode = pbNew;
}
else if (pbCode[0] == 0xeb) { // jmp +imm8
PBYTE pbNew = pbCode + 2 + *(CHAR *)&pbCode[1];
DETOUR_TRACE(("%p->%p: skipped over short jump.\n", pbCode, pbNew));
pbCode = pbNew;
}
else {
break;
}
}
return pbCode;
}
inline BOOL detour_does_code_end_function(PBYTE pbCode)
{
if (pbCode[0] == 0xeb || // jmp +imm8
pbCode[0] == 0xe9 || // jmp +imm32
pbCode[0] == 0xe0 || // jmp eax
pbCode[0] == 0xc2 || // ret +imm8
pbCode[0] == 0xc3 || // ret
pbCode[0] == 0xcc) { // brk
return TRUE;
}
else if (pbCode[0] == 0xff && pbCode[1] == 0x25) { // jmp [+imm32]
return TRUE;
}
else if ((pbCode[0] == 0x26 || // jmp es:
pbCode[0] == 0x2e || // jmp cs:
pbCode[0] == 0x36 || // jmp ss:
pbCode[0] == 0xe3 || // jmp ds:
pbCode[0] == 0x64 || // jmp fs:
pbCode[0] == 0x65) && // jmp gs:
pbCode[1] == 0xff && // jmp [+imm32]
pbCode[2] == 0x25) {
return TRUE;
}
return FALSE;
}
inline BOOL detour_is_code_filler(PBYTE pbCode)
{
if (pbCode[0] == 0x90) {
return TRUE; //nop
}
return FALSE;
}
#endif // DETOURS_X64
//////////////////////////////////////////////////////////////////////// IA64.
//
#ifdef DETOURS_IA64
struct _DETOUR_TRAMPOLINE
{
// On the IA64, a trampoline is used for both incoming and outgoing calls.
//
// The trampoline contains the following bundles for the outgoing call:
// movl gp=target_gp;
// <relocated target bundle>
// brl target_code;
//
// The trampoline contains the following bundles for the incoming call:
// alloc r41=ar.pfs, b, 0, 8, 0
// mov r40=rp
//
// adds r50=0, r39
// adds r49=0, r38
// adds r48=0, r37 ;;
//
// adds r47=0, r36
// adds r46=0, r35
// adds r45=0, r34
//
// adds r44=0, r33
// adds r43=0, r32
// adds r42=0, gp ;;
//
// movl gp=ffffffff`ffffffff ;;
//
// brl.call.sptk.few rp=disas!TestCodes+20e0 (00000000`00404ea0) ;;
//
// adds gp=0, r42
// mov rp=r40, +0 ;;
// mov.i ar.pfs=r41
//
// br.ret.sptk.many rp ;;
//
// This way, we only have to relocate a single bundle.
//
// The complicated incoming trampoline is required because we have to
// create an additional stack frame so that we save and restore the gp.
// We must do this because gp is a caller-saved register, but not saved
// if the caller thinks the target is in the same DLL, which changes
// when we insert a detour.
//
DETOUR_IA64_BUNDLE bMovlTargetGp; // Bundle which sets target GP
BYTE rbCode[sizeof(DETOUR_IA64_BUNDLE)]; // moved bundle.
DETOUR_IA64_BUNDLE bBrlRemainEip; // Brl to pbRemain
// Target of brl inserted in target function
DETOUR_IA64_BUNDLE bAllocFrame; // alloc frame
DETOUR_IA64_BUNDLE bSave37to39; // save r37, r38, r39.
DETOUR_IA64_BUNDLE bSave34to36; // save r34, r35, r36.
DETOUR_IA64_BUNDLE bSaveGPto33; // save gp, r32, r33.
DETOUR_IA64_BUNDLE bMovlDetourGp; // set detour GP.
DETOUR_IA64_BUNDLE bCallDetour; // call detour.
DETOUR_IA64_BUNDLE bPopFrameGp; // pop frame and restore gp.
DETOUR_IA64_BUNDLE bReturn; // return to caller.
PLABEL_DESCRIPTOR pldTrampoline;
BYTE rbRestore[sizeof(DETOUR_IA64_BUNDLE)]; // original target bundle.
BYTE cbRestore; // size of original target code.
BYTE cbCode; // size of moved target code.
PBYTE pbRemain; // first instruction after moved code. [free list]
PBYTE pbDetour; // first instruction of detour function.
PPLABEL_DESCRIPTOR ppldDetour; // [pbDetour,gpDetour]
PPLABEL_DESCRIPTOR ppldTarget; // [pbTarget,gpDetour]
};
enum {
SIZE_OF_JMP = sizeof(DETOUR_IA64_BUNDLE)
};
inline PBYTE detour_skip_jmp(PBYTE pPointer, PVOID *ppGlobals)
{
PBYTE pGlobals = NULL;
PBYTE pbCode = NULL;
if (pPointer != NULL) {
PPLABEL_DESCRIPTOR ppld = (PPLABEL_DESCRIPTOR)pPointer;
pbCode = (PBYTE)ppld->EntryPoint;
pGlobals = (PBYTE)ppld->GlobalPointer;
}
if (ppGlobals != NULL) {
*ppGlobals = pGlobals;
}
if (pbCode == NULL) {
return NULL;
}
DETOUR_IA64_BUNDLE *pb = (DETOUR_IA64_BUNDLE *)pbCode;
// IA64 Local Import Jumps look like:
// addl r2=ffffffff`ffe021c0, gp ;;
// ld8 r2=[r2]
// nop.i 0 ;;
//
// ld8 r3=[r2], 8 ;;
// ld8 gp=[r2]
// mov b6=r3, +0
//
// nop.m 0
// nop.i 0
// br.cond.sptk.few b6
//
// 002024000200100b
if ((pb[0].wide[0] & 0xfffffc000603ffff) == 0x002024000200100b &&
pb[0].wide[1] == 0x0004000000203008 &&
pb[1].wide[0] == 0x001014180420180a &&
pb[1].wide[1] == 0x07000830c0203008 &&
pb[2].wide[0] == 0x0000000100000010 &&
pb[2].wide[1] == 0x0080006000000200) {
ULONG64 offset =
((pb[0].wide[0] & 0x0000000001fc0000) >> 18) | // imm7b
((pb[0].wide[0] & 0x000001ff00000000) >> 25) | // imm9d
((pb[0].wide[0] & 0x00000000f8000000) >> 11); // imm5c
if (pb[0].wide[0] & 0x0000020000000000) { // sign
offset |= 0xffffffffffe00000;
}
PBYTE pbTarget = pGlobals + offset;
DETOUR_TRACE(("%p: potential import jump, target=%p\n", pb, pbTarget));
if (detour_is_imported(pbCode, pbTarget) && *(PBYTE*)pbTarget != NULL) {
DETOUR_TRACE(("%p: is import jump, label=%p\n", pb, *(PBYTE *)pbTarget));
PPLABEL_DESCRIPTOR ppld = (PPLABEL_DESCRIPTOR)*(PBYTE *)pbTarget;
pbCode = (PBYTE)ppld->EntryPoint;
pGlobals = (PBYTE)ppld->GlobalPointer;
if (ppGlobals != NULL) {
*ppGlobals = pGlobals;
}
}
}
return pbCode;
}
inline BOOL detour_does_code_end_function(PBYTE pbCode)
{
(void)pbCode;
return FALSE;
}
inline BOOL detour_is_code_filler(PBYTE pbCode)
{
(void)pbCode;
return FALSE;
}
#endif // DETOURS_IA64
#ifdef DETOURS_ARM
#define DETOURS_PFUNC_TO_PBYTE(p) ((PBYTE)(((ULONG_PTR)(p)) & ~(ULONG_PTR)1))
#define DETOURS_PBYTE_TO_PFUNC(p) ((PBYTE)(((ULONG_PTR)(p)) | (ULONG_PTR)1))
struct _DETOUR_TRAMPOLINE
{
// A Thumb-2 instruction can be 2 or 4 bytes long.
BYTE rbCode[62]; // target code + jmp to pbRemain
BYTE cbCode; // size of moved target code.
BYTE cbCodeBreak; // padding to make debugging easier.
BYTE rbRestore[22]; // original target code.
BYTE cbRestore; // size of original target code.
BYTE cbRestoreBreak; // padding to make debugging easier.
PBYTE pbRemain; // first instruction after moved code. [free list]
PBYTE pbDetour; // first instruction of detour function.
};
enum {
SIZE_OF_JMP = 8
};
inline PBYTE align4(PBYTE pValue)
{
return (PBYTE)(((ULONG)pValue) & ~(ULONG)3u);
}
inline ULONG fetch_thumb_opcode(PBYTE pbCode)
{
ULONG Opcode = *(UINT16 *)&pbCode[0];
if (Opcode >= 0xe800) {
Opcode = (Opcode << 16) | *(UINT16 *)&pbCode[2];
}
return Opcode;
}
inline void write_thumb_opcode(PBYTE &pbCode, ULONG Opcode)
{
if (Opcode >= 0x10000) {
*((UINT16*&)pbCode)++ = Opcode >> 16;
}
*((UINT16*&)pbCode)++ = (UINT16)Opcode;
}
PBYTE detour_gen_jmp_immediate(PBYTE pbCode, PBYTE *ppPool, PBYTE pbJmpVal)
{
PBYTE pbLiteral;
if (ppPool != NULL) {
*ppPool = *ppPool - 4;
pbLiteral = *ppPool;
}
else {
pbLiteral = align4(pbCode + 6);
}
*((PBYTE*&)pbLiteral) = DETOURS_PBYTE_TO_PFUNC(pbJmpVal);
LONG delta = pbLiteral - align4(pbCode + 4);
write_thumb_opcode(pbCode, 0xf8dff000 | delta); // LDR PC,[PC+n]
if (ppPool == NULL) {
if (((ULONG)pbCode & 2) != 0) {
write_thumb_opcode(pbCode, 0xdefe); // BREAK
}
pbCode += 4;
}
return pbCode;
}
inline PBYTE detour_gen_brk(PBYTE pbCode, PBYTE pbLimit)
{
while (pbCode < pbLimit) {
write_thumb_opcode(pbCode, 0xdefe);
}
return pbCode;
}
inline PBYTE detour_skip_jmp(PBYTE pbCode, PVOID *ppGlobals)
{
if (pbCode == NULL) {
return NULL;
}
if (ppGlobals != NULL) {
*ppGlobals = NULL;
}
pbCode = (PBYTE)DETOURS_PFUNC_TO_PBYTE(pbCode);
ULONG Opcode = fetch_thumb_opcode(pbCode);
if ((Opcode & 0xfbf08f00) == 0xf2400c00) { // movw r12,#xxxx
ULONG Opcode2 = fetch_thumb_opcode(pbCode+4);
if ((Opcode2 & 0xfbf08f00) == 0xf2c00c00) { // movt r12,#xxxx
ULONG Opcode3 = fetch_thumb_opcode(pbCode+8);
if (Opcode3 == 0xf8dcf000) { // ldr pc,[r12]
PBYTE pbTarget = (PBYTE)(((Opcode2 << 12) & 0xf7000000) |
((Opcode2 << 1) & 0x08000000) |
((Opcode2 << 16) & 0x00ff0000) |
((Opcode >> 4) & 0x0000f700) |
((Opcode >> 15) & 0x00000800) |
((Opcode >> 0) & 0x000000ff));
if (detour_is_imported(pbCode, pbTarget)) {
PBYTE pbNew = *(PBYTE *)pbTarget;
// [GalenH] __debugbreak();
pbNew = DETOURS_PFUNC_TO_PBYTE(pbNew);
DETOUR_TRACE(("%p->%p: skipped over import table.\n", pbCode, pbNew));
return pbNew;
}
}
}
}
return pbCode;
}
inline BOOL detour_does_code_end_function(PBYTE pbCode)
{
ULONG Opcode = fetch_thumb_opcode(pbCode);
if ((Opcode & 0xffffff87) == 0x4700 || // bx <reg>
(Opcode & 0xf800d000) == 0xf0009000) { // b <imm20>
return TRUE;
}
if ((Opcode & 0xffff8000) == 0xe8bd8000) { // pop {...,pc}
__debugbreak();
return TRUE;
}
if ((Opcode & 0xffffff00) == 0x0000bd00) { // pop {...,pc}
__debugbreak();
return TRUE;
}
return FALSE;
}
inline BOOL detour_is_code_filler(PBYTE pbCode)
{
if (pbCode[0] == 0x00 && pbCode[1] == 0xbf) {
return TRUE; //nop
}
return FALSE;
}
#endif // DETOURS_ARM
//////////////////////////////////////////////// Trampoline Memory Management.
//
struct DETOUR_REGION
{
ULONG dwSignature;
DETOUR_REGION * pNext; // Next region in list of regions.
DETOUR_TRAMPOLINE * pFree; // List of free trampolines in this region.
};
typedef DETOUR_REGION * PDETOUR_REGION;
const ULONG DETOUR_REGION_SIGNATURE = 'Rrtd';
const ULONG DETOUR_REGION_SIZE = 0x10000;
const ULONG DETOUR_TRAMPOLINES_PER_REGION = (DETOUR_REGION_SIZE
/ sizeof(DETOUR_TRAMPOLINE)) - 1;
static PDETOUR_REGION s_pRegions = NULL; // List of all regions.
static PDETOUR_REGION s_pRegion = NULL; // Default region.
static void detour_writable_trampoline_regions()
{
// Mark all of the regions as writable.
for (PDETOUR_REGION pRegion = s_pRegions; pRegion != NULL; pRegion = pRegion->pNext) {
DWORD dwOld;
VirtualProtect(pRegion, DETOUR_REGION_SIZE, PAGE_EXECUTE_READWRITE, &dwOld);
}
}
static void detour_runnable_trampoline_regions()
{
HANDLE hProcess = GetCurrentProcess();
// Mark all of the regions as executable.
for (PDETOUR_REGION pRegion = s_pRegions; pRegion != NULL; pRegion = pRegion->pNext) {
DWORD dwOld;
VirtualProtect(pRegion, DETOUR_REGION_SIZE, PAGE_EXECUTE_READ, &dwOld);
FlushInstructionCache(hProcess, pRegion, DETOUR_REGION_SIZE);
}
}
static PDETOUR_TRAMPOLINE detour_alloc_trampoline(PBYTE pbTarget)
{
// We have to place trampolines within +/- 2GB of target.
// The allocation code assumes that
PDETOUR_TRAMPOLINE pLo = (PDETOUR_TRAMPOLINE)
((pbTarget > (PBYTE)0x7ff80000)
? pbTarget - 0x7ff80000 : (PBYTE)(ULONG_PTR)DETOUR_REGION_SIZE);
PDETOUR_TRAMPOLINE pHi = (PDETOUR_TRAMPOLINE)
((pbTarget < (PBYTE)0xffffffff80000000)
? pbTarget + 0x7ff80000 : (PBYTE)0xfffffffffff80000);
DETOUR_TRACE(("[%p..%p..%p]\n", pLo, pbTarget, pHi));
PDETOUR_TRAMPOLINE pTrampoline = NULL;
// Insure that there is a default region.
if (s_pRegion == NULL && s_pRegions != NULL) {
s_pRegion = s_pRegions;
}
// First check the default region for an valid free block.
if (s_pRegion != NULL && s_pRegion->pFree != NULL &&
s_pRegion->pFree >= pLo && s_pRegion->pFree <= pHi) {
found_region:
pTrampoline = s_pRegion->pFree;
// do a last sanity check on region.
if (pTrampoline < pLo || pTrampoline > pHi) {
return NULL;
}
s_pRegion->pFree = (PDETOUR_TRAMPOLINE)pTrampoline->pbRemain;
memset(pTrampoline, 0xcc, sizeof(*pTrampoline));
return pTrampoline;
}
// Then check the existing regions for a valid free block.
for (s_pRegion = s_pRegions; s_pRegion != NULL; s_pRegion = s_pRegion->pNext) {
if (s_pRegion != NULL && s_pRegion->pFree != NULL &&
s_pRegion->pFree >= pLo && s_pRegion->pFree <= pHi) {
goto found_region;
}
}
// We need to allocate a new region.
// Round pbTarget down to 64K block.
pbTarget = pbTarget - (PtrToUlong(pbTarget) & 0xffff);
// First we search down (within the valid region)
DETOUR_TRACE((" Looking for free region below %p:\n", pbTarget));
PBYTE pbTry;
for (pbTry = pbTarget; pbTry > (PBYTE)pLo;) {
MEMORY_BASIC_INFORMATION mbi;
DETOUR_TRACE((" Try %p\n", pbTry));
if (pbTry >= (PBYTE)(ULONG_PTR)0x70000000 &&
pbTry <= (PBYTE)(ULONG_PTR)0x80000000) {
// Skip region reserved for system DLLs.
pbTry = (PBYTE)(ULONG_PTR)(0x70000000 - DETOUR_REGION_SIZE);
}
ZeroMemory(&mbi, sizeof(mbi));
if (!VirtualQuery(pbTry, &mbi, sizeof(mbi))) {
break;
}
DETOUR_TRACE((" Try %p => %p..%p %6x\n",
pbTry,
mbi.BaseAddress,
(PBYTE)mbi.BaseAddress + mbi.RegionSize - 1,
mbi.State));
if (mbi.State == MEM_FREE && mbi.RegionSize >= DETOUR_REGION_SIZE) {
s_pRegion = (DETOUR_REGION*)VirtualAlloc(pbTry,
DETOUR_REGION_SIZE,
MEM_COMMIT|MEM_RESERVE,
PAGE_EXECUTE_READWRITE);
if (s_pRegion != NULL) {
alloced_region:
s_pRegion->dwSignature = DETOUR_REGION_SIGNATURE;
s_pRegion->pFree = NULL;
s_pRegion->pNext = s_pRegions;
s_pRegions = s_pRegion;
DETOUR_TRACE((" Allocated region %p..%p\n\n",
s_pRegion, ((PBYTE)s_pRegion) + DETOUR_REGION_SIZE - 1));
// Put everything but the first trampoline on the free list.
PBYTE pFree = NULL;
pTrampoline = ((PDETOUR_TRAMPOLINE)s_pRegion) + 1;
for (int i = DETOUR_TRAMPOLINES_PER_REGION - 1; i > 1; i--) {
pTrampoline[i].pbRemain = pFree;
pFree = (PBYTE)&pTrampoline[i];
}
s_pRegion->pFree = (PDETOUR_TRAMPOLINE)pFree;
goto found_region;
}
else {
DETOUR_TRACE(("Error: %p %d\n", pbTry, GetLastError()));
break;
}
}
pbTry = (PBYTE)mbi.AllocationBase - DETOUR_REGION_SIZE;
}
DETOUR_TRACE((" Looking for free region above %p:\n", pbTarget));
for (pbTry = pbTarget; pbTry < (PBYTE)pHi;) {
MEMORY_BASIC_INFORMATION mbi;
if (pbTry >= (PBYTE)(ULONG_PTR)0x70000000 &&
pbTry <= (PBYTE)(ULONG_PTR)0x80000000) {
// Skip region reserved for system DLLs.
pbTry = (PBYTE)(ULONG_PTR)(0x80000000 + DETOUR_REGION_SIZE);
}
ZeroMemory(&mbi, sizeof(mbi));
if (!VirtualQuery(pbTry, &mbi, sizeof(mbi))) {
break;
}
DETOUR_TRACE((" Try %p => %p..%p %6x\n",
pbTry,
mbi.BaseAddress,
(PBYTE)mbi.BaseAddress + mbi.RegionSize - 1,
mbi.State));
if (mbi.State == MEM_FREE && mbi.RegionSize >= DETOUR_REGION_SIZE) {
ULONG_PTR extra = ((ULONG_PTR)pbTry) & (DETOUR_REGION_SIZE - 1);
if (extra != 0) {
// WinXP64 returns free areas that aren't REGION aligned to
// 32-bit applications.
ULONG_PTR adjust = DETOUR_REGION_SIZE - extra;
mbi.RegionSize -= adjust;
((PBYTE&)mbi.BaseAddress) += adjust;
DETOUR_TRACE(("--Try %p => %p..%p %6x\n",
pbTry,
mbi.BaseAddress,
(PBYTE)mbi.BaseAddress + mbi.RegionSize - 1,
mbi.State));
pbTry = (PBYTE)mbi.BaseAddress;
}
s_pRegion = (DETOUR_REGION*)VirtualAlloc(pbTry,
DETOUR_REGION_SIZE,
MEM_COMMIT|MEM_RESERVE,
PAGE_EXECUTE_READWRITE);
if (s_pRegion != NULL) {
goto alloced_region;
}
else {
DETOUR_TRACE(("Error: %p %d\n", pbTry, GetLastError()));
}
}
pbTry = (PBYTE)mbi.BaseAddress + mbi.RegionSize;
}
DETOUR_TRACE(("Couldn't find available memory region!\n"));
return NULL;
}
static VOID detour_free_trampoline(PDETOUR_TRAMPOLINE pTrampoline)
{
PDETOUR_REGION pRegion = (PDETOUR_REGION)
((ULONG_PTR)pTrampoline & ~(ULONG_PTR)0xffff);
memset(pTrampoline, 0, sizeof(*pTrampoline));
pTrampoline->pbRemain = (PBYTE)pRegion->pFree;
pRegion->pFree = pTrampoline;
}
///////////////////////////////////////////////////////// Transaction Structs.
//
struct DetourThread
{
DetourThread * pNext;
HANDLE hThread;
};
struct DetourOperation
{
DetourOperation * pNext;
BOOL fIsRemove;
PBYTE * ppbPointer;
PBYTE pbTarget;
PDETOUR_TRAMPOLINE pTrampoline;
ULONG dwPerm;
};
static BOOL s_fIgnoreTooSmall = FALSE;
static LONG s_nPendingThreadId = 0; // Thread owning pending transaction.
static LONG s_nPendingError = NO_ERROR;
static PVOID * s_ppPendingError = NULL;
static DetourThread * s_pPendingThreads = NULL;
static DetourOperation * s_pPendingOperations = NULL;
//////////////////////////////////////////////////////////////////////////////
//
PVOID WINAPI DetourCodeFromPointer(PVOID pPointer, PVOID *ppGlobals)
{
return detour_skip_jmp((PBYTE)pPointer, ppGlobals);
}
//////////////////////////////////////////////////////////// Transaction APIs.
//
VOID WINAPI DetourSetIgnoreTooSmall(BOOL fIgnore)
{
s_fIgnoreTooSmall = fIgnore;
}
LONG WINAPI DetourTransactionBegin()
{
// Only one transaction is allowed at a time.
if (s_nPendingThreadId != 0) {
return ERROR_INVALID_OPERATION;
}
// Make sure only one thread can start a transaction.
if (InterlockedCompareExchange(&s_nPendingThreadId, (LONG)GetCurrentThreadId(), 0) != 0) {
return ERROR_INVALID_OPERATION;
}
s_fIgnoreTooSmall = FALSE;
s_pPendingOperations = NULL;
s_pPendingThreads = NULL;
s_nPendingError = NO_ERROR;
s_ppPendingError = NULL;
// Make sure the trampoline pages are writable.
detour_writable_trampoline_regions();
return NO_ERROR;
}
LONG WINAPI DetourTransactionAbort()
{
if (s_nPendingThreadId != (LONG)GetCurrentThreadId()) {
return ERROR_INVALID_OPERATION;
}
// Restore all of the page permissions.
for (DetourOperation *o = s_pPendingOperations; o != NULL;) {
// We don't care if this fails, because the code is still accessible.
DWORD dwOld;
VirtualProtect(o->pbTarget, o->pTrampoline->cbRestore,
o->dwPerm, &dwOld);
if (!o->fIsRemove) {
if (o->pTrampoline) {
detour_free_trampoline(o->pTrampoline);
o->pTrampoline = NULL;
}
}
DetourOperation *n = o->pNext;
delete o;
o = n;
}
s_pPendingOperations = NULL;
// Make sure the trampoline pages are no longer writable.
detour_runnable_trampoline_regions();
// Resume any suspended threads.
for (DetourThread *t = s_pPendingThreads; t != NULL;) {
// There is nothing we can do if this fails.
ResumeThread(t->hThread);
DetourThread *n = t->pNext;
delete t;
t = n;
}
s_pPendingThreads = NULL;
s_nPendingThreadId = 0;
return NO_ERROR;
}
LONG WINAPI DetourTransactionCommit()
{
return DetourTransactionCommitEx(NULL);
}
LONG WINAPI DetourTransactionCommitEx(PVOID **pppFailedPointer)
{
if (pppFailedPointer != NULL) {
// Used to get the last error.
*pppFailedPointer = s_ppPendingError;
}
if (s_nPendingThreadId != (LONG)GetCurrentThreadId()) {
return ERROR_INVALID_OPERATION;
}
// If any of the pending operations failed, then we abort the whole transaction.
if (s_nPendingError != NO_ERROR) {
DETOUR_BREAK();
DetourTransactionAbort();
return s_nPendingError;
}
// Common variables.
DetourOperation *o;
DetourThread *t;
// Insert or remove each of the detours.
for (o = s_pPendingOperations; o != NULL; o = o->pNext) {
if (o->fIsRemove) {
CopyMemory(o->pbTarget,
o->pTrampoline->rbRestore,
o->pTrampoline->cbRestore);
#ifdef DETOURS_IA64
*o->ppbPointer = (PBYTE)o->pTrampoline->ppldTarget;
#endif // DETOURS_IA64
#ifdef DETOURS_X86
*o->ppbPointer = o->pbTarget;
#endif // DETOURS_X86
#ifdef DETOURS_X64
*o->ppbPointer = o->pbTarget;
#endif // DETOURS_X64
#ifdef DETOURS_ARM
*o->ppbPointer = DETOURS_PBYTE_TO_PFUNC(o->pbTarget);
#endif // DETOURS_ARM
}
else {
DETOUR_TRACE(("detours: pbTramp =%p, pbRemain=%p, pbDetour=%p, cbRestore=%d\n",
o->pTrampoline,
o->pTrampoline->pbRemain,
o->pTrampoline->pbDetour,
o->pTrampoline->cbRestore));
DETOUR_TRACE(("detours: pbTarget=%p: "
"%02x %02x %02x %02x "
"%02x %02x %02x %02x "
"%02x %02x %02x %02x [before]\n",
o->pbTarget,
o->pbTarget[0], o->pbTarget[1], o->pbTarget[2], o->pbTarget[3],
o->pbTarget[4], o->pbTarget[5], o->pbTarget[6], o->pbTarget[7],
o->pbTarget[8], o->pbTarget[9], o->pbTarget[10], o->pbTarget[11]));
#ifdef DETOURS_IA64
((DETOUR_IA64_BUNDLE*)o->pbTarget)
->SetBrl((UINT64)&o->pTrampoline->bAllocFrame);
*o->ppbPointer = (PBYTE)&o->pTrampoline->pldTrampoline;
#endif // DETOURS_IA64
#ifdef DETOURS_X64
detour_gen_jmp_indirect(o->pTrampoline->rbCodeIn, &o->pTrampoline->pbDetour);
PBYTE pbCode = detour_gen_jmp_immediate(o->pbTarget, o->pTrampoline->rbCodeIn);
pbCode = detour_gen_brk(pbCode, o->pTrampoline->pbRemain);
*o->ppbPointer = o->pTrampoline->rbCode;