jadeite/injector/src/dll.c

#include <stdio.h>

#include <inject.h>
#include <envs.h>

#include <game_p.h>

typedef char *(*wgufn_t)(wchar_t* path); // wine_get_unix_file_name

const char *J_MB_TITLE = "Jadeite Launcher Payload";

BOOL WINAPI DllMain(HINSTANCE inst, DWORD reason, LPVOID reserved) {
    // Only listen for attach
    if (reason != DLL_PROCESS_ATTACH) {
        return TRUE;
    }

    // Get target EXE path
    char *targetExe = getenv(ENV_EXE_PATH);
    
    // Get the path of the DLL to inject
    char *injectDll = getenv(ENV_DLL_PATH);

    // Get game commandline
    char *cmdline = getenv(ENV_PROC_CMD);

    // Compute the working directory path
    char workdir[MAX_PATH];
    strcpy(workdir, targetExe);
    *(strrchr(workdir, '\\')) = '\0';

    // SAFETY: verify that the injector is not inside the game directory
    HMODULE kernel32 = GetModuleHandleA("kernel32.dll");
    wgufn_t wine_get_unix_file_name = (wgufn_t)GetProcAddress(kernel32, "wine_get_unix_file_name");

    if (wine_get_unix_file_name) {
        wchar_t wInjectDll[MAX_PATH], wWorkdir[MAX_PATH];
        MultiByteToWideChar(CP_UTF8, 0, injectDll, strlen(injectDll) + 1, wInjectDll, MAX_PATH);
        MultiByteToWideChar(CP_UTF8, 0, workdir, strlen(workdir) + 1, wWorkdir, MAX_PATH);

        char *unixInjectDll = wine_get_unix_file_name(wInjectDll);
        char *unixWorkdir = wine_get_unix_file_name(wWorkdir);

        char startsWith = 0;
        while (*unixInjectDll != '\0' && *unixWorkdir != '\0') {
            startsWith = *unixInjectDll == *unixWorkdir;
            if (!startsWith) break;

            unixInjectDll++, unixWorkdir++;
        }

        HANDLE heap = GetProcessHeap();
        HeapFree(heap, 0, unixInjectDll);
        HeapFree(heap, 0, unixWorkdir);

        if (startsWith) {
            MessageBoxA(NULL, "Putting the patcher (or any other foreign PE binaries) inside the game directory is dangerous! Please move it elsewhere.", J_MB_TITLE, MB_OK | MB_ICONERROR);
            exit(1);
        }
    } else {
        MessageBoxA(NULL, "Could not find wine_get_unix_file_name! Wine version too old?", J_MB_TITLE, MB_OK | MB_ICONWARNING);
    }

    // Start the game
    STARTUPINFO si;
    ZeroMemory(&si, sizeof(si));

    PROCESS_INFORMATION pi;
    si.cb = sizeof(si);
    ZeroMemory(&pi, sizeof(pi));

    if (!CreateProcessA(
        NULL,
        cmdline,
        NULL,
        NULL,
        FALSE,
        CREATE_SUSPENDED,
        NULL,
        workdir,
        &si,
        &pi
    )) {
        char message[64];
        sprintf(message, "Failed to start game process: %ld", GetLastError());
        MessageBoxA(NULL, message, J_MB_TITLE, MB_OK | MB_ICONERROR);

        exit(1);
    }

    // Inject
    void *payloadStart = &_binary_game_p_o_p_game_p_bin_start;
    size_t payloadSize = (size_t)&_binary_game_p_o_p_game_p_bin_size;
    inject(pi.hProcess, payloadStart, payloadSize, injectDll);

    // Optional: wait for user input before resuming (useful for debugging) 
    char *waitEnabled = getenv("WAIT_BEFORE_RESUME");
    if (waitEnabled && strcmp(waitEnabled, "") != 0) {
        char message[64];
        sprintf(message, "PID: %ld. Press OK to continue", pi.dwProcessId);
        MessageBoxA(NULL, message, J_MB_TITLE, MB_OK | MB_ICONINFORMATION);
    }

    // Resume the process
    ResumeThread(pi.hThread);

    // The launcher process should now hang untill the game terminates
    WaitForSingleObject(pi.hProcess, INFINITE);

    return TRUE;
}