internal static void* MemoryGetProcAddress(MEMORYMODULE mod, byte* name)
{
MEMORYMODULE module = mod;
byte* codeBase = module.codeBase;
uint idx = 0;
IMAGE_EXPORT_DIRECTORY* exports;
IMAGE_DATA_DIRECTORY* directory = GET_HEADER_DICTIONARY(module, IMAGE_DIRECTORY_ENTRY_EXPORT);
if (directory->Size == 0)
// no export table found
return null;
exports = (IMAGE_EXPORT_DIRECTORY*)(codeBase + directory->VirtualAddress);
if (exports->NumberOfNames == 0 || exports->NumberOfFunctions == 0)
// DLL doesn't export anything
return null;
if (HIWORD(name) == 0)
{
// load function by ordinal value
if (LOWORD(name) < exports->Base)
return null;
idx = LOWORD(name) - exports->Base;
}
else if (exports->NumberOfNames == 0)
return null;
else
{
ExportNameEntry found;
// Lazily build name table and sort it by names
if (module.nameExportsTable == null)
{
uint i;
uint* nameRef = (uint*)(codeBase + exports->AddressOfNames);
ushort* ordinal = (ushort*)(codeBase + exports->AddressOfNameOrdinals);
ExportNameEntry[] entry = new ExportNameEntry[exports->NumberOfNames];
module.nameExportsTable = entry;
for (i = 0; i < exports->NumberOfNames; i++, nameRef++, ordinal++)
entry[i] = new ExportNameEntry
{
name = codeBase + (*nameRef),
idx = *ordinal
};
Array.Sort(module.nameExportsTable, _compare);
}
// search function name in list of exported names with binary search
ExportNameEntry tmp = new ExportNameEntry { name = name };
int foundIndex = Array.BinarySearch(module.nameExportsTable, tmp, tmp);
found = foundIndex < 0 ? null : module.nameExportsTable[foundIndex];
if (found == null)
// exported symbol not found
return null;
idx = found.idx;
}
if (idx > exports->NumberOfFunctions)
// name <. ordinal number don't match
return null;
// AddressOfFunctions contains the RVAs to the "real" functions
return (void*)(codeBase + (*(uint*)(codeBase + exports->AddressOfFunctions + (idx * 4))));
}
private static int _compare(ExportNameEntry a, ExportNameEntry b)
{
return strcmp(a.name, b.name);
}
