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/*
* Proxy.h -- Definitions for proxy-related functionality
*
* The proxy works roughly as follows:
* - We define our exports in proxy.c (computer generated)
* - loadProxy initializes the proxy:
* 1. Look up the name of this DLL
* 2. Find the original DLL with the same name
* 3. Load the original DLL
* 4. Load all functions into originalFunctions array
*
* For more information, refer to proxy.c
*/
#pragma once
#pragma warning( disable : 4267 6387 6386 )
#include <Windows.h>
#include <Shlwapi.h>
#include "assert_util.h"
#include <crtdbg.h>
#define ALT_POSTFIX L"_alt.dll"
#define DLL_POSTFIX L".dll"
extern FARPROC originalFunctions[];
extern void loadFunctions(HMODULE dll);
// Load the proxy functions into memory
inline void loadProxy(wchar_t *moduleName)
{
size_t module_name_len = wcslen(moduleName);
size_t alt_name_len = module_name_len + STR_LEN(ALT_POSTFIX);
wchar_t *alt_name = memalloc(sizeof(wchar_t) * alt_name_len);
wmemcpy(alt_name, moduleName, module_name_len);
wmemcpy(alt_name + module_name_len, ALT_POSTFIX, STR_LEN(ALT_POSTFIX));
wchar_t *dll_path = NULL; // The final DLL path
const int alt_full_path_len = GetFullPathNameW(alt_name, 0, NULL, NULL);
wchar_t *alt_full_path = memalloc(sizeof(wchar_t) * alt_full_path_len);
GetFullPathNameW(alt_name, alt_full_path_len, alt_full_path, NULL);
memfree(alt_name);
LOG("Looking for original DLL from %S\n", alt_full_path);
// Try to look for the alternative first in the same directory.
HMODULE handle = LoadLibrary(alt_full_path);
if (handle == NULL)
{
size_t system_dir_len = GetSystemDirectoryW(NULL, 0);
dll_path = memalloc(sizeof(wchar_t) * (system_dir_len + module_name_len + STR_LEN(DLL_POSTFIX)));
_ASSERTE(dll_path != nullptr);
GetSystemDirectoryW(dll_path, system_dir_len);
dll_path[system_dir_len - 1] = L'\\';
wmemcpy(dll_path + system_dir_len, moduleName, module_name_len);
wmemcpy(dll_path + system_dir_len + module_name_len, DLL_POSTFIX, STR_LEN(DLL_POSTFIX));
LOG("Looking for original DLL from %S\n", dll_path);
handle = LoadLibraryW(dll_path);
}
ASSERT_F(handle != NULL, L"Unable to load the original %s.dll (looked from system directory and from %s_alt.dll)!",
moduleName, moduleName);
memfree(alt_full_path);
memfree(dll_path);
loadFunctions(handle);
}