FARPROC WINAPI
__delayLoadHelper2(
PCImgDelayDescr pidd,
FARPROC * ppfnIATEntry
) {
// Set up some data we use for the hook procs but also useful for
// our own use
//
InternalImgDelayDescr idd = {
pidd->grAttrs,
PFromRva<LPCSTR>(pidd->rvaDLLName),
PFromRva<HMODULE*>(pidd->rvaHmod),
PFromRva<PImgThunkData>(pidd->rvaIAT),
PFromRva<PCImgThunkData>(pidd->rvaINT),
PFromRva<PCImgThunkData>(pidd->rvaBoundIAT),
PFromRva<PCImgThunkData>(pidd->rvaUnloadIAT),
pidd->dwTimeStamp
};
DelayLoadInfo dli = {
sizeof DelayLoadInfo,
pidd,
ppfnIATEntry,
idd.szName,
{ 0 },
0,
0,
0
};
if (0 == (idd.grAttrs & dlattrRva)) {
PDelayLoadInfo rgpdli[1] = { &dli };
RaiseException(
VcppException(ERROR_SEVERITY_ERROR, ERROR_INVALID_PARAMETER),
0,
1,
PULONG_PTR(rgpdli)
);
return 0;
}
HMODULE hmod = *idd.phmod;
// Calculate the index for the IAT entry in the import address table
// N.B. The INT entries are ordered the same as the IAT entries so
// the calculation can be done on the IAT side.
//
const unsigned iIAT = IndexFromPImgThunkData(PCImgThunkData(ppfnIATEntry), idd.pIAT);
const unsigned iINT = iIAT;
PCImgThunkData pitd = &(idd.pINT[iINT]);
dli.dlp.fImportByName = !IMAGE_SNAP_BY_ORDINAL(pitd->u1.Ordinal);
if (dli.dlp.fImportByName) {
dli.dlp.szProcName = LPCSTR(PFromRva<PIMAGE_IMPORT_BY_NAME>(RVA(UINT_PTR(pitd->u1.AddressOfData)))->Name);
}
else {
dli.dlp.dwOrdinal = DWORD(IMAGE_ORDINAL(pitd->u1.Ordinal));
}
// Call the initial hook. If it exists and returns a function pointer,
// abort the rest of the processing and just return it for the call.
//
FARPROC pfnRet = NULL;
if (__pfnDliNotifyHook2) {
pfnRet = ((*__pfnDliNotifyHook2)(dliStartProcessing, &dli));
if (pfnRet != NULL) {
goto HookBypass;
}
}
// Check to see if we need to try to load the library.
//
if (hmod == 0) {
if (__pfnDliNotifyHook2) {
hmod = HMODULE(((*__pfnDliNotifyHook2)(dliNotePreLoadLibrary, &dli)));
}
if (hmod == 0) {
hmod = ::LoadLibraryEx(dli.szDll, NULL, 0);
}
if (hmod == 0) {
dli.dwLastError = ::GetLastError();
if (__pfnDliFailureHook2) {
// when the hook is called on LoadLibrary failure, it will
// return 0 for failure and an hmod for the lib if it fixed
// the problem.
//
hmod = HMODULE((*__pfnDliFailureHook2)(dliFailLoadLib, &dli));
}
if (hmod == 0) {
PDelayLoadInfo rgpdli[1] = { &dli };
RaiseException(
VcppException(ERROR_SEVERITY_ERROR, ERROR_MOD_NOT_FOUND),
0,
1,
PULONG_PTR(rgpdli)
);
// If we get to here, we blindly assume that the handler of the exception
// has magically fixed everything up and left the function pointer in
// dli.pfnCur.
//
return dli.pfnCur;
}
}
// Store the library handle. If it is already there, we infer
// that another thread got there first, and we need to do a
// FreeLibrary() to reduce the refcount
//
HMODULE hmodT = HMODULE(InterlockedExchangePointer((PVOID *) idd.phmod, PVOID(hmod)));
if (hmodT == hmod) {
::FreeLibrary(hmod);
}
}
// Go for the procedure now.
//
dli.hmodCur = hmod;
if (__pfnDliNotifyHook2) {
pfnRet = (*__pfnDliNotifyHook2)(dliNotePreGetProcAddress, &dli);
}
if (pfnRet == 0) {
if (pidd->rvaBoundIAT && pidd->dwTimeStamp) {
// bound imports exist...check the timestamp from the target image
//
PIMAGE_NT_HEADERS pinh(PinhFromImageBase(hmod));
if (pinh->Signature == IMAGE_NT_SIGNATURE &&
TimeStampOfImage(pinh) == idd.dwTimeStamp &&
FLoadedAtPreferredAddress(pinh, hmod)) {
// Everything is good to go, if we have a decent address
// in the bound IAT!
//
pfnRet = FARPROC(UINT_PTR(idd.pBoundIAT[iIAT].u1.Function));
if (pfnRet != 0) {
goto SetEntryHookBypass;
}
}
}
pfnRet = ::GetProcAddress(hmod, dli.dlp.szProcName);
}
if (pfnRet == 0) {
dli.dwLastError = ::GetLastError();
if (__pfnDliFailureHook2) {
// when the hook is called on GetProcAddress failure, it will
// return 0 on failure and a valid proc address on success
//
pfnRet = (*__pfnDliFailureHook2)(dliFailGetProc, &dli);
}
if (pfnRet == 0) {
PDelayLoadInfo rgpdli[1] = { &dli };
RaiseException(
VcppException(ERROR_SEVERITY_ERROR, ERROR_PROC_NOT_FOUND),
0,
1,
PULONG_PTR(rgpdli)
);
// If we get to here, we blindly assume that the handler of the exception
// has magically fixed everything up and left the function pointer in
// dli.pfnCur.
//
pfnRet = dli.pfnCur;
}
}
SetEntryHookBypass:
*ppfnIATEntry = pfnRet;
HookBypass:
if (__pfnDliNotifyHook2) {
dli.dwLastError = 0;
dli.hmodCur = hmod;
dli.pfnCur = pfnRet;
(*__pfnDliNotifyHook2)(dliNoteEndProcessing, &dli);
}
return pfnRet;
}
FARPROC WINAPI _EXPFUNC __delayLoadHelper(ImgDelayDescr *pidd, FARPROC *ppfnIATEntry)
{
HMODULE hmod;
unsigned iINT;
FARPROC pfnRet;
const IMAGE_THUNK_DATA * pitd;
// Set up some data we use for the hook procs but also useful for
// our own use
//
DelayLoadInfo dli;
memset(&dli, 0, sizeof(dli));
dli.cb = sizeof (DelayLoadInfo);
dli.pidd = pidd;
dli.ppfn = ppfnIATEntry;
dli.szDll = pidd->szName;
hmod = pidd->hmod;
// Calculate the index for the name in the import name table.
// N.B. it is ordered the same as the IAT entries so the calculation
// comes from the IAT side.
//
iINT = IndexFromPImgThunkData((const IMAGE_THUNK_DATA *)ppfnIATEntry, pidd->pIAT);
pitd = &((pidd->pINT)[iINT]);
if ((dli.dlp.fImportByName = ((pitd->u1.Ordinal & IMAGE_ORDINAL_FLAG) == 0)) != 0)
{
dli.dlp.szProcName = (LPCSTR)((IMAGE_IMPORT_BY_NAME*)pitd->u1.AddressOfData)->Name;
}
else
{
dli.dlp.dwOrdinal = IMAGE_ORDINAL(pitd->u1.Ordinal);
}
// Call the initial hook. If it exists and returns a function pointer,
// abort the rest of the processing and just return it for the call.
//
pfnRet = NULL;
if (__pfnDliNotifyHook)
{
if ((pfnRet = (*__pfnDliNotifyHook)(dliNoteStartProcessing, &dli)) != 0)
{
goto HookBypass;
}
}
if (hmod == 0)
{
if (__pfnDliNotifyHook)
{
hmod = (HMODULE)(*__pfnDliNotifyHook)(dliNotePreLoadLibrary, &dli);
}
if (hmod == 0)
{
hmod = LoadLibrary(dli.szDll);
}
if (hmod == 0)
{
dli.dwLastError = GetLastError();
if (__pfnDliFailureHook)
{
// when the hook is called on LoadLibrary failure, it will
// return 0 for failure and an hmod for the lib if it fixed
// the problem.
//
hmod = (HMODULE)(*__pfnDliFailureHook)(dliFailLoadLibrary, &dli);
}
if (hmod == 0)
{
DelayLoadInfo * pdli = &dli;
RaiseException(
BCPPException(ERROR_SEVERITY_ERROR, ERROR_MOD_NOT_FOUND),
0,
1,
(PDWORD)&pdli
);
// If we get to here, we blindly assume that the handler of the exception
// has magically fixed everything up and left the function pointer in
// dli.pfnCur.
//
return dli.pfnCur;
}
}
// Store the library handle. If it is already there, we infer
// that another thread got there first, and we need to do a
// FreeLibrary() to reduce the refcount
//
EnterCriticalSection(&UnloadInfoCS);
if (!pidd->hmod)
{
AddToUnloadList(pidd);
pidd->hmod = hmod;
}
else
{
FreeLibrary(hmod);
hmod = pidd->hmod;
}
LeaveCriticalSection(&UnloadInfoCS);
}
// Go for the procedure now.
dli.hmodCur = hmod;
if (__pfnDliNotifyHook)
{
pfnRet = (*__pfnDliNotifyHook)(dliNotePreGetProcAddress, &dli);
}
if (pfnRet == 0)
{
if (pidd->pBoundIAT && pidd->dwTimeStamp)
{
// bound imports exist...check the timestamp from the target image
PIMAGE_NT_HEADERS pinh = PinhFromImageBase(hmod);
if (pinh->Signature == IMAGE_NT_SIGNATURE &&
TimeStampOfImage(pinh) == pidd->dwTimeStamp &&
FLoadedAtPreferredAddress(pinh, hmod))
{
OverlayIAT(pidd->pIAT, pidd->pBoundIAT);
pfnRet = (FARPROC)pidd->pIAT[iINT].u1.Function;
goto HookBypass;
}
}
pfnRet = GetProcAddress(hmod, dli.dlp.szProcName);
}
if (pfnRet == 0)
{
dli.dwLastError = GetLastError();
if (__pfnDliFailureHook)
{
// when the hook is called on GetProcAddress failure, it will
// return 0 on failure and a valid proc address on success
//
pfnRet = (*__pfnDliFailureHook)(dliFailGetProcAddress, &dli);
}
if (pfnRet == 0)
{
DelayLoadInfo * pdli = &dli;
RaiseException(
BCPPException(ERROR_SEVERITY_ERROR, ERROR_PROC_NOT_FOUND),
0,
1,
(PDWORD)&pdli
);
// If we get to here, we blindly assume that the handler of the exception
// has magically fixed everything up and left the function pointer in
// dli.pfnCur.
//
pfnRet = dli.pfnCur;
}
}
*ppfnIATEntry = pfnRet;
HookBypass:
if (__pfnDliNotifyHook)
{
dli.dwLastError = 0;
dli.hmodCur = hmod;
dli.pfnCur = pfnRet;
(*__pfnDliNotifyHook)(dliNoteEndProcessing, &dli);
}
return pfnRet;
}