Fix `TlsGetValue` & more (#48)

`TlsGetValue` disambiguates 0 and an error by relying on `GetLastError`. Depending on the program state, `GetLastError` could be non-0, even though `TlsGetValue` succeeded. Resolve this by always setting `wibo::lastError`. This matches the behavior described by the documentation.

Additionally, when reading resources, later versions of mwcc and mwld call `GetModuleHandleA` with the program path, and then call `LoadStringA` on that handle. Support this behavior by _actually_ loading the PE at the path passed in to `GetModuleHandleA`, instead of assuming it's the current program.

(This is especially useful because sjiswrap relies on overriding `GetModuleFileNameA`, so the wrapped program reads its own resources, rather than sjiswrap's.)

Other small changes:
- Add ms-win-crt `exit` & run atexit funcs
- Implements vcruntime `memmove`
- Implements kernel32 `GetModuleFileNameA`

common.h

@@ -7,6 +7,7 @@
 #include <sys/stat.h>
 #include <unistd.h>
 #include <vector>
+#include <memory>
 
 // On Windows, the incoming stack is aligned to a 4 byte boundary.
 // force_align_arg_pointer will realign the stack to match GCC's 16 byte alignment.
@@ -53,6 +54,7 @@ typedef unsigned char BYTE;
 #define ERROR_HANDLE_EOF 38
 #define ERROR_NOT_SUPPORTED 50
 #define ERROR_INVALID_PARAMETER 87
+#define ERROR_INSUFFICIENT_BUFFER 122
 #define ERROR_NEGATIVE_SEEK 131
 #define ERROR_ALREADY_EXISTS 183
 
@@ -98,7 +100,7 @@ namespace wibo {
 	struct Executable {
 		Executable();
 		~Executable();
-		bool loadPE(FILE *file);
+		bool loadPE(FILE *file, bool exec);
 
 		void *imageBuffer;
 		size_t imageSize;
@@ -115,6 +117,20 @@ namespace wibo {
 			return fromRVA<T>((uint32_t) rva);
 		}
 	};
+	struct ModuleInfo {
+		std::string name;
+		const wibo::Module* module = nullptr;
+		std::unique_ptr<wibo::Executable> executable;
+	};
 
 	extern Executable *mainModule;
-}
+	Executable *executableFromModule(HMODULE module);
+
+	/**
+	 * HMODULE will be `nullptr` or `mainModule->imageBuffer` if it's the main module,
+	 * otherwise it will be a pointer to a `wibo::ModuleInfo`.
+	 */
+	inline bool isMainModule(HMODULE hModule) {
+		return hModule == nullptr || hModule == mainModule->imageBuffer;
+	}
+} // namespace wibo

dll/crt.cpp

@@ -1,5 +1,7 @@
 #include "common.h"
 
+#include <vector>
+
 typedef void (*_PVFV)();
 typedef int (*_PIFV)();
 
@@ -19,6 +21,8 @@ namespace crt {
 
 int _commode = 0;
 
+std::vector<_PVFV> atexitFuncs;
+
 void WIN_ENTRY _initterm(const _PVFV *ppfn, const _PVFV *end) {
 	do {
 		if (_PVFV pfn = *++ppfn) {
@@ -48,7 +52,8 @@ int WIN_ENTRY _set_fmode(int mode) {
 int *WIN_ENTRY __p__commode() { return &_commode; }
 
 int WIN_ENTRY _crt_atexit(void (*func)()) {
-	DEBUG_LOG("STUB: _crt_atexit(%p)\n", func);
+	DEBUG_LOG("_crt_atexit(%p)\n", func);
+	atexitFuncs.push_back(func);
 	return 0;
 }
 
@@ -85,6 +90,15 @@ int *WIN_ENTRY __p___argc() { return &wibo::argc; }
 
 size_t WIN_ENTRY strlen(const char *str) { return ::strlen(str); }
 
+void WIN_ENTRY exit(int status) {
+	DEBUG_LOG("exit(%i)\n", status);
+	for (auto it = atexitFuncs.rbegin(); it != atexitFuncs.rend(); ++it) {
+		DEBUG_LOG("Calling atexit function %p\n", *it);
+		(*it)();
+	}
+	::exit(status);
+}
+
 } // namespace crt
 
 static void *resolveByName(const char *name) {
@@ -118,6 +132,8 @@ static void *resolveByName(const char *name) {
 		return (void *)crt::__p___argc;
 	if (strcmp(name, "strlen") == 0)
 		return (void *)crt::strlen;
+	if (strcmp(name, "exit") == 0)
+		return (void *)crt::exit;
 	return nullptr;
 }
 

dll/kernel32.cpp

@@ -250,14 +250,14 @@ namespace kernel32 {
 
 	unsigned int WIN_FUNC WaitForSingleObject(void *hHandle, unsigned int dwMilliseconds) {
 		DEBUG_LOG("WaitForSingleObject (%u)\n", dwMilliseconds);
-		
+
 		// TODO - wait on other objects?
 
 		// TODO: wait for less than forever
-		assert(dwMilliseconds == 0xffffffff); 
+		assert(dwMilliseconds == 0xffffffff);
 
 		processes::Process* process = processes::processFromHandle(hHandle, false);
-		
+
 		int status;
 		waitpid(process->pid, &status, 0);
 
@@ -268,7 +268,7 @@ namespace kernel32 {
 			// Specific exit codes don't really map onto any of these situations - we just know it's bad.
 			// Specify a non-zero exit code to alert our parent process something's gone wrong.
 			DEBUG_LOG("WaitForSingleObject: Child process exited abnormally - returning exit code 1.");
-			process->exitCode = 1; 
+			process->exitCode = 1;
 		}
 
 		return 0;
@@ -366,30 +366,42 @@ namespace kernel32 {
 			}
 		}
 		DEBUG_LOG("...returning nothing\n");
-		return 0xFFFFFFFF;
+		wibo::lastError = 1;
+		return 0xFFFFFFFF; // TLS_OUT_OF_INDEXES
 	}
+
 	unsigned int WIN_FUNC TlsFree(unsigned int dwTlsIndex) {
 		DEBUG_LOG("TlsFree(%u)\n", dwTlsIndex);
 		if (dwTlsIndex >= 0 && dwTlsIndex < MAX_TLS_VALUES && tlsValuesUsed[dwTlsIndex]) {
 			tlsValuesUsed[dwTlsIndex] = false;
 			return 1;
 		} else {
+			wibo::lastError = 1;
 			return 0;
 		}
 	}
+
 	void *WIN_FUNC TlsGetValue(unsigned int dwTlsIndex) {
-		// DEBUG_LOG("TlsGetValue(%u)\n", dwTlsIndex);
-		if (dwTlsIndex >= 0 && dwTlsIndex < MAX_TLS_VALUES && tlsValuesUsed[dwTlsIndex])
-			return tlsValues[dwTlsIndex];
-		else
-			return 0;
+		// DEBUG_LOG("TlsGetValue(%u)", dwTlsIndex);
+		void *result = nullptr;
+		if (dwTlsIndex >= 0 && dwTlsIndex < MAX_TLS_VALUES && tlsValuesUsed[dwTlsIndex]) {
+			result = tlsValues[dwTlsIndex];
+			// See https://learn.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-TlsGetValue#return-value
+			wibo::lastError = ERROR_SUCCESS;
+		} else {
+			wibo::lastError = 1;
+		}
+		// DEBUG_LOG(" -> %p\n", result);
+		return result;
 	}
+
 	unsigned int WIN_FUNC TlsSetValue(unsigned int dwTlsIndex, void *lpTlsValue) {
 		// DEBUG_LOG("TlsSetValue(%u, %p)\n", dwTlsIndex, lpTlsValue);
 		if (dwTlsIndex >= 0 && dwTlsIndex < MAX_TLS_VALUES && tlsValuesUsed[dwTlsIndex]) {
 			tlsValues[dwTlsIndex] = lpTlsValue;
 			return 1;
 		} else {
+			wibo::lastError = 1;
 			return 0;
 		}
 	}
@@ -1303,16 +1315,42 @@ namespace kernel32 {
 		}
 	}
 
-	unsigned int WIN_FUNC GetModuleFileNameA(void* hModule, char* lpFilename, unsigned int nSize) {
+	DWORD WIN_FUNC GetModuleFileNameA(HMODULE hModule, LPSTR lpFilename, DWORD nSize) {
 		DEBUG_LOG("GetModuleFileNameA (hModule=%p, nSize=%i)\n", hModule, nSize);
+		if (lpFilename == nullptr) {
+			wibo::lastError = ERROR_INVALID_PARAMETER;
+			return 0;
+		}
 
-		*lpFilename = 0; // just NUL terminate
+		std::string path;
+		if (wibo::isMainModule(hModule)) {
+			const auto exePath = files::pathFromWindows(wibo::argv[0]);
+			const auto absPath = std::filesystem::absolute(exePath);
+			path = files::pathToWindows(absPath);
+		} else {
+			path = static_cast<wibo::ModuleInfo *>(hModule)->name;
+		}
+		const size_t len = path.size();
+		if (nSize == 0) {
+			wibo::lastError = ERROR_INSUFFICIENT_BUFFER;
+			return 0;
+		}
 
-		wibo::lastError = 0;
-		return 0;
+		const size_t copyLen = std::min(len, nSize - 1);
+		memcpy(lpFilename, path.c_str(), copyLen);
+		if (copyLen < nSize) {
+			lpFilename[copyLen] = 0;
+		}
+		if (copyLen < len) {
+			wibo::lastError = ERROR_INSUFFICIENT_BUFFER;
+			return nSize;
+		}
+
+		wibo::lastError = ERROR_SUCCESS;
+		return copyLen;
 	}
 
-	unsigned int WIN_FUNC GetModuleFileNameW(void* hModule, uint16_t* lpFilename, unsigned int nSize) {
+	DWORD WIN_FUNC GetModuleFileNameW(HMODULE hModule, LPWSTR lpFilename, DWORD nSize) {
 		DEBUG_LOG("GetModuleFileNameW (hModule=%p, nSize=%i)\n", hModule, nSize);
 
 		*lpFilename = 0; // just NUL terminate

dll/user32.cpp

@@ -57,8 +57,7 @@ namespace user32 {
 		return (unsigned int*)(rsrcBase + langEntry);
 	}
 
-	static const char *getStringFromTable(unsigned int uID) {
-		wibo::Executable *mod = wibo::mainModule;
+	static const char *getStringFromTable(wibo::Executable *mod, unsigned int uID) {
 		unsigned int tableID = (uID >> 4) + 1;
 		unsigned int entryID = uID & 15;
 		unsigned int* stringTable = getResourceByID(mod, 6, tableID, 1033);
@@ -82,7 +81,11 @@ namespace user32 {
 
 	int WIN_FUNC LoadStringA(void* hInstance, unsigned int uID, char* lpBuffer, int cchBufferMax) {
 		DEBUG_LOG("LoadStringA %p %d %d\n", hInstance, uID, cchBufferMax);
-		const char* s = getStringFromTable(uID);
+		wibo::Executable *mod = wibo::executableFromModule(hInstance);
+		if (!mod) {
+			return 0;
+		}
+		const char* s = getStringFromTable(mod, uID);
 		if (!s) {
 			return 0;
 		}

dll/vcruntime.cpp

@@ -8,6 +8,8 @@ void *WIN_ENTRY memset(void *dest, int ch, size_t count) { return ::memset(dest,
 
 int WIN_ENTRY memcmp(const void *buf1, const void *buf2, size_t count) { return ::memcmp(buf1, buf2, count); }
 
+void *WIN_ENTRY memmove(void *dest, const void *src, size_t count) { return ::memmove(dest, src, count); }
+
 } // namespace vcruntime
 
 static void *resolveByName(const char *name) {
@@ -17,6 +19,8 @@ static void *resolveByName(const char *name) {
 		return (void *)vcruntime::memset;
 	if (strcmp(name, "memcmp") == 0)
 		return (void *)vcruntime::memcmp;
+	if (strcmp(name, "memmove") == 0)
+		return (void *)vcruntime::memmove;
 	return nullptr;
 }
 

loader.cpp

@@ -116,7 +116,13 @@ wibo::Executable::~Executable() {
 	}
 }
 
-bool wibo::Executable::loadPE(FILE *file) {
+/**
+ * Load a PE file into memory.
+ *
+ * @param file The file to load.
+ * @param exec Whether to make the loaded image executable.
+ */
+bool wibo::Executable::loadPE(FILE *file, bool exec) {
 	// Skip to PE header
 	fseek(file, 0x3C, SEEK_SET);
 	uint32_t offsetToPE = read32(file);
@@ -145,7 +151,12 @@ bool wibo::Executable::loadPE(FILE *file) {
 
 	// Build buffer
 	imageSize = header32.sizeOfImage;
-	imageBuffer = mmap((void *) header32.imageBase, header32.sizeOfImage, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANONYMOUS|MAP_FIXED|MAP_PRIVATE, -1, 0);
+	if (exec) {
+		imageBuffer = mmap((void *)header32.imageBase, header32.sizeOfImage, PROT_READ | PROT_WRITE | PROT_EXEC,
+						   MAP_ANONYMOUS | MAP_FIXED | MAP_PRIVATE, -1, 0);
+	} else {
+		imageBuffer = mmap(nullptr, header32.sizeOfImage, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+	}
 	memset(imageBuffer, 0, header32.sizeOfImage);
 	if (imageBuffer == MAP_FAILED) {
 		perror("Image mapping failed!");
@@ -165,7 +176,7 @@ bool wibo::Executable::loadPE(FILE *file) {
 		name[8] = 0;
 		DEBUG_LOG("Section %d: name=%s addr=%x size=%x (raw=%x) ptr=%x\n", i, name, section.virtualAddress, section.virtualSize, section.sizeOfRawData, section.pointerToRawData);
 
-		void *sectionBase = (void *) (header32.imageBase + section.virtualAddress);
+		void *sectionBase = (void *) ((uintptr_t) imageBuffer + section.virtualAddress);
 		if (section.pointerToRawData > 0 && section.sizeOfRawData > 0) {
 			// Grab this data
 			long savePos = ftell(file);
@@ -179,6 +190,11 @@ bool wibo::Executable::loadPE(FILE *file) {
 		}
 	}
 
+	if (!exec) {
+		// No need to resolve imports
+		return true;
+	}
+
 	// Handle imports
 	PEImportDirectoryEntry *dir = fromRVA<PEImportDirectoryEntry>(header32.importTable.virtualAddress);
 

main.cpp

@@ -31,7 +31,7 @@ void wibo::debug_log(const char *fmt, ...) {
 
 		vfprintf(stderr, fmt, args);
 	}
-	
+
 	va_end(args);
 }
 
@@ -110,11 +110,6 @@ const wibo::Module * wibo::modules[] = {
 	nullptr,
 };
 
-struct ModuleInfo {
-	std::string name;
-	const wibo::Module* module = nullptr;
-};
-
 HMODULE wibo::loadModule(const char *dllName) {
 	auto *result = new ModuleInfo;
 	result->name = dllName;
@@ -151,6 +146,32 @@ void *wibo::resolveFuncByOrdinal(HMODULE module, uint16_t ordinal) {
 	return resolveMissingFuncOrdinal(info->name.c_str(), ordinal);
 }
 
+wibo::Executable *wibo::executableFromModule(HMODULE module) {
+	if (wibo::isMainModule(module)) {
+		return wibo::mainModule;
+	}
+
+	auto info = static_cast<wibo::ModuleInfo *>(module);
+	if (!info->executable) {
+		DEBUG_LOG("wibo::executableFromModule: loading %s\n", info->name.c_str());
+		auto executable = std::make_unique<wibo::Executable>();
+		const auto path = files::pathFromWindows(info->name.c_str());
+		FILE *f = fopen(path.c_str(), "rb");
+		if (!f) {
+			perror("wibo::executableFromModule");
+			return nullptr;
+		}
+		bool result = executable->loadPE(f, false);
+		fclose(f);
+		if (!result) {
+			DEBUG_LOG("wibo::executableFromModule: failed to load %s\n", path.c_str());
+			return nullptr;
+		}
+		info->executable = std::move(executable);
+	}
+	return info->executable.get();
+}
+
 struct UNICODE_STRING {
 	unsigned short Length;
 	unsigned short MaximumLength;
@@ -295,7 +316,7 @@ int main(int argc, char **argv) {
 		return 1;
 	}
 
-	exec.loadPE(f);
+	exec.loadPE(f, true);
 	fclose(f);
 
 	// 32-bit windows only reserves the lowest 2GB of memory for use by a process (https://www.tenouk.com/WinVirtualAddressSpace.html)