setupapi: Make sure machine name is non-empty before failing.

dlls/setupapi/devinst.c

@@ -1163,7 +1163,7 @@ SetupDiCreateDeviceInfoListExW(const GUID *ClassGuid,
     TRACE("%s %p %s %p\n", debugstr_guid(ClassGuid), hwndParent,
       debugstr_w(MachineName), Reserved);
 
-    if (MachineName != NULL)
+    if (MachineName && *MachineName)
     {
         FIXME("remote support is not implemented\n");
         SetLastError(ERROR_INVALID_MACHINENAME);
@@ -2371,7 +2371,7 @@ HDEVINFO WINAPI SetupDiGetClassDevsExW(
         set = SetupDiCreateDeviceInfoListExW(class, parent, machine, reserved);
     if (set)
     {
-        if (machine)
+        if (machine && *machine)
             FIXME("%s: unimplemented for remote machines\n",
                     debugstr_w(machine));
         else if (flags & DIGCF_DEVICEINTERFACE)
@@ -3562,7 +3562,7 @@ HKEY WINAPI SetupDiOpenClassRegKeyExW(
     LPCWSTR lpKeyName;
     LONG l;
 
-    if (MachineName != NULL)
+    if (MachineName && *MachineName)
     {
         FIXME("Remote access not supported yet!\n");
         return INVALID_HANDLE_VALUE;

dlls/setupapi/tests/devinst.c

@@ -261,6 +261,7 @@ static void test_SetupDiCreateDeviceInfoListEx(void)
     DWORD error;
     static CHAR notnull[] = "NotNull";
     static const WCHAR machine[] = { 'd','u','m','m','y',0 };
+    static const WCHAR empty[] = { 0 };
 
     SetLastError(0xdeadbeef);
     /* create empty DeviceInfoList, but set Reserved to a value, which is not NULL */
@@ -290,6 +291,14 @@ static void test_SetupDiCreateDeviceInfoListEx(void)
     /* destroy DeviceInfoList */
     ret = pSetupDiDestroyDeviceInfoList(devlist);
     ok(ret, "SetupDiDestroyDeviceInfoList failed : %d\n", error);
+
+    /* create empty DeviceInfoList with empty machine name */
+    devlist = pSetupDiCreateDeviceInfoListExW(NULL, NULL, empty, NULL);
+    ok(devlist && devlist != INVALID_HANDLE_VALUE, "SetupDiCreateDeviceInfoListExW failed : %p %d (expected != %p)\n", devlist, error, INVALID_HANDLE_VALUE);
+
+    /* destroy DeviceInfoList */
+    ret = pSetupDiDestroyDeviceInfoList(devlist);
+    ok(ret, "SetupDiDestroyDeviceInfoList failed : %d\n", error);
 }
 
 static void test_SetupDiOpenClassRegKeyExA(void)