kernel/ext2: Add support for symbolic links

Otherwise it would just be pointing to the old parent fs, and we don't want that.

kernel/config.cmake.template

@@ -10,3 +10,8 @@
 
 # Example: Adding a compiler flag. This will optimize the kernel aggressively (warning: untested, use at your own discretion).
 # target_compile_options(moon PRIVATE -O3)
+
+# Uncomment the line below to allow any filename on file/directory creation (by default, the kernel prohibits filenames with 
+# control characters, leading/trailing spaces, problematic characters and invalid UTF-8). Keep in mind that this restriction
+# is only enforced when creating files; existing files with such illegal filenames are parsed correctly and fully usable.
+# target_compile_definitions(moon PRIVATE MOON_DISABLE_FILENAME_RESTRICTIONS)

kernel/src/fs/VFS.cpp

@@ -101,6 +101,11 @@ namespace VFS
 
     Result<void> validate_filename(StringView name)
     {
+#ifdef MOON_DISABLE_FILENAME_RESTRICTIONS
+        (void)name;
+        return {};
+#endif
+
         // Forbid problematic characters that could cause trouble in shell scripts and the like.
         if (strpbrk(name.chars(), "*?:[]\"<>\\")) return err(EINVAL);