introduced new dynamic symbol resolver for CRT functions

1 files changed, 95 insertions, 37 deletions

diff --git a/TestDLL/dllmain.cpp b/TestDLL/dllmain.cpp
index 1097050..860a9a9 100644
--- a/TestDLL/dllmain.cpp
+++ b/TestDLL/dllmain.cpp
@@ -3,43 +3,103 @@
 #include <vector>
 #include <string>
 #include <sstream>
-
-extern "C"
-BOOL WINAPI _CRT_INIT(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpReserved);
+#include <array>
 
 #pragma comment(lib, "vcruntime.lib")
 
-typedef void(*myfree_t)(void *ptr);
-typedef void*(*mymalloc_t)(size_t n);
-typedef int(*_mycallnewh_t)(size_t n);
 
-static myfree_t myfree;
-static mymalloc_t mymalloc;
-static _mycallnewh_t _mycallnewh;
+struct ResolvedDllEntry {
+	const char * const baseDllName;
+	const char * const functionName;
+
+	HMODULE moduleBase;
+	FARPROC resolvedProc;
+};
+
+#define DLL_ENTRY(dll_name, function_name) \
+	{ dll_name, function_name, NULL, NULL }
+#define MSVCRT_ENTRY(function_name) DLL_ENTRY("msvcrt.dll", function_name)
+
+static struct ResolvedDllEntry resolved_smybols[] = {
+	MSVCRT_ENTRY("malloc"), MSVCRT_ENTRY("free"), MSVCRT_ENTRY("_callnewh"),
+	MSVCRT_ENTRY("abort"), MSVCRT_ENTRY("calloc"), MSVCRT_ENTRY("frexp"),
+	MSVCRT_ENTRY("islower"), MSVCRT_ENTRY("isspace"), MSVCRT_ENTRY("isupper"),
+	MSVCRT_ENTRY("ldexp"), MSVCRT_ENTRY("localeconv"),
+	MSVCRT_ENTRY("memchr"), MSVCRT_ENTRY("memcmp"), MSVCRT_ENTRY("memcpy")
+};
+static const SIZE_T resolved_symbols_size =
+sizeof(resolved_smybols) / sizeof(resolved_smybols[0]);
 
-void _invalid_parameter_noinfo_noreturn(void) {
+enum SymbolIndex {
+	SYM_MALLOC, SYM_FREE, SYM_CALLNEWH, SYM_INVALID_PARAMETER_NOINFO_NORETURN,
+	SYM_ABORT, SYM_CALLOC, SYM_FREXP,
+	SYM_ISLOWER, SYM_ISSPACE, SYM_ISUPPER,
+	SYM_LDEXP, SYM_LOCALECONV,
+	SYM_MEMCHR, SYM_MEMCMP, SYM_MEMCPY
+};
+
+#define WRAPPER_FUNCTION(symbol_index, linker_function_name, return_type, ...) \
+	typedef return_type (* symbol_index ## _FN)(__VA_ARGS__); \
+	extern "C" \
+	return_type linker_function_name(__VA_ARGS__)
+#define RUN_REAL_FN(symbol_index, ...) \
+	(((symbol_index ## _FN)resolved_smybols[symbol_index].resolvedProc)(__VA_ARGS__))
+
+WRAPPER_FUNCTION(SYM_MALLOC, malloc, void *, size_t n) {
+	return RUN_REAL_FN(SYM_MALLOC, n);
+}
+WRAPPER_FUNCTION(SYM_FREE, free, void, void *p) {
+	RUN_REAL_FN(SYM_FREE, p);
+}
+WRAPPER_FUNCTION(SYM_CALLNEWH, _callnewh, int, size_t n) {
+	return RUN_REAL_FN(SYM_CALLNEWH, n);
+}
+WRAPPER_FUNCTION(SYM_INVALID_PARAMETER_NOINFO_NORETURN,
+	_invalid_parameter_noinfo_noreturn, void, void) {
 	ExitProcess(1);
 }
-
-extern "C"
-void * malloc(size_t n) {
-	return mymalloc(n);
+WRAPPER_FUNCTION(SYM_ABORT, abort, void, void) {
+	RUN_REAL_FN(SYM_ABORT);
 }
-
-extern "C"
-void free(void *ptr) {
-	myfree(ptr);
+WRAPPER_FUNCTION(SYM_CALLOC, calloc, void *, size_t n, size_t s) {
+	return RUN_REAL_FN(SYM_CALLOC, n, s);
+}
+WRAPPER_FUNCTION(SYM_FREXP, frexp, double, double x, int *expptr) {
+	return RUN_REAL_FN(SYM_FREXP, x, expptr);
+}
+WRAPPER_FUNCTION(SYM_ISLOWER, islower, int, int c) {
+	return RUN_REAL_FN(SYM_ISLOWER, c);
+}
+WRAPPER_FUNCTION(SYM_ISSPACE, isspace, int, int c) {
+	return RUN_REAL_FN(SYM_ISSPACE, c);
+}
+WRAPPER_FUNCTION(SYM_ISUPPER, isupper, int, int c) {
+	return RUN_REAL_FN(SYM_ISUPPER, c);
 }
 
+
 extern "C"
-int _callnewh(size_t n) {
-	return _mycallnewh(n);
-}
+static bool resolve_all_symbols(void) {
+	bool result = true;
 
-void MyFnResolve(void) {
+	for (SIZE_T i = 0; i < 3; ++i) {
+		resolved_smybols[i].moduleBase = LoadLibraryA(resolved_smybols[i].baseDllName);
 
+		if (!resolved_smybols[i].moduleBase) {
+			result = false;
+			continue;
+		}
+		resolved_smybols[i].resolvedProc = GetProcAddress(resolved_smybols[i].moduleBase,
+			resolved_smybols[i].functionName);
+		if (!resolved_smybols[i].resolvedProc) {
+			result = false;
+		}
+	}
+
+	return result;
 }
 
+
 void APIENTRY LibEntry(PVOID user_ptr)
 {
 	static bool firstEntry = true;
@@ -47,34 +107,32 @@ void APIENTRY LibEntry(PVOID user_ptr)
 	if (firstEntry) {
 		firstEntry = false;
 
-		HMODULE msvcrtModule = LoadLibraryA("msvcrt.dll");
-		mymalloc = (mymalloc_t) GetProcAddress(msvcrtModule, "malloc");
-		myfree = (myfree_t) GetProcAddress(msvcrtModule, "free");
-		_mycallnewh = (_mycallnewh_t)GetProcAddress(msvcrtModule, "_callnewh");
-		if (!mymalloc || !myfree || !_mycallnewh) {
+		if (!resolve_all_symbols()) {
+			MessageBoxA(NULL,
+				"COULD NOT RESOLVE ALL DYNAMIC DLL SYMBOLS !!!",
+				"TestDLL Notification",
+				MB_OK | MB_ICONINFORMATION);
 			return;
 		}
+		void *bla = malloc(10);
+		free(bla);
 #if 1
 		std::string text;
 		std::vector<DWORD> blubb;
 		text = "DllMain from TestDLL: ";
 		blubb.push_back(1);
 		blubb.push_back(2);
-		//std::wstringstream muh;
+		//std::stringstream muh;
 		//muh << "bla" << "," << "blubb";
-#endif
 		MessageBoxA(NULL,
 			text.c_str(),
 			"TestDLL Notification",
 			MB_OK | MB_ICONINFORMATION);
-#if 0
-		if (firstEntry &&
-			!_CRT_INIT(NULL, DLL_PROCESS_ATTACH, NULL)) {
-			MessageBoxA(NULL,
-				"DllMain _CRT_INIT failed",
-				"TestDLL Notification",
-				MB_OK | MB_ICONINFORMATION);
-		}
+#else
+		MessageBoxA(NULL,
+			"TEST !!!",
+			"TestDLL Notification",
+			MB_OK | MB_ICONINFORMATION);
 #endif
 	}
 }
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