allow launching DF to work under wine

package/windows/launchdf.c

@@ -1,7 +1,26 @@
+#include <process.h>
 #include <windows.h>
 
-int WINAPI wWinMain(HINSTANCE hi, HINSTANCE hpi, PWSTR cmd, int ns)
+static BOOL is_running_on_wine() {
-{
+    static const char *(CDECL *pwine_get_version)(void);
+    HMODULE hntdll = GetModuleHandle("ntdll.dll");
+    if(!hntdll)
+        return FALSE;
+
+    pwine_get_version = (void *)GetProcAddress(hntdll, "wine_get_version");
+    return !!pwine_get_version;
+}
+
+static LPCWSTR launch_via_steam_posix() {
+    const char* argv[] = { "/bin/sh", "-c", "\"steam -applaunch 975370\"", NULL };
+
+    // does not return on success
+    _execv(argv[0], argv);
+
+    return L"Could not launch Dwarf Fortress";
+}
+
+static LPCWSTR launch_via_steam_windows() {
     STARTUPINFOW si;
     PROCESS_INFORMATION pi;
 
@@ -12,28 +31,42 @@ int WINAPI wWinMain(HINSTANCE hi, HINSTANCE hpi, PWSTR cmd, int ns)
     WCHAR steamPath[1024];
     DWORD datasize = 1024;
 
-    LONG retCode = RegGetValueW(HKEY_CURRENT_USER, L"SOFTWARE\\Valve\\Steam", L"SteamExe", RRF_RT_REG_SZ, NULL, &steamPath, &datasize);
+    LONG retCode = RegGetValueW(HKEY_CURRENT_USER, L"SOFTWARE\\Valve\\Steam",
+            L"SteamExe", RRF_RT_REG_SZ, NULL, &steamPath, &datasize);
+
+    MessageBoxW(NULL, steamPath, NULL, 0);
 
     if (retCode != ERROR_SUCCESS)
-    {
+        return L"Could not find Steam client executable";
-        MessageBoxW(NULL, L"Could not find Steam client executable", NULL, 0);
-        exit(1);
-    }
 
     WCHAR commandLine[1024] = L"steam.exe -applaunch 975370";
 
-    if (CreateProcessW(steamPath,
+    if (CreateProcessW(steamPath, commandLine,
-        commandLine,
+            NULL, NULL, FALSE, 0, NULL, NULL, &si, &pi) == 0)
-        NULL,
+        return L"Could not launch Dwarf Fortress";
-        NULL,
+
-        FALSE,
+    return NULL;
-        0,
+}
-        NULL,
+
-        NULL,
+// this method doesn't properly attribute Steam playtime metrics to DF,
-        &si,
+// but that's better than not having DF start at all.
-        &pi) == 0)
+static BOOL launch_direct() {
-    {
+    STARTUPINFOA si;
-        MessageBoxW(NULL, L"could not launch Dwarf Fortress", NULL, 0);
+    PROCESS_INFORMATION pi;
+
+    ZeroMemory(&si, sizeof(si));
+    si.cb = sizeof(si);
+    ZeroMemory(&pi, sizeof(pi));
+
+    return CreateProcessA("Dwarf Fortress.exe",
+            NULL, NULL, NULL, FALSE, 0, NULL, NULL, &si, &pi);
+}
+
+int WINAPI wWinMain(HINSTANCE hi, HINSTANCE hpi, PWSTR cmd, int ns) {
+    LPCWSTR err =  is_running_on_wine() ? launch_via_steam_posix() : launch_via_steam_windows();
+
+    if (err && !launch_direct()) {
+        MessageBoxW(NULL, err, NULL, 0);
         exit(1);
     }