+ return match_pattern_list(path, path_nchars, pats);
+}
+
+/* Returns %true if the specified absolute path to a file in the WIM image can
+ * be subject to external backing when extracted. Otherwise returns %false. */
+static bool
+can_externally_back_path(const wchar_t *path, size_t path_nchars,
+ const struct win32_apply_ctx *ctx)
+{
+ if (in_prepopulate_list(path, path_nchars, ctx))
+ return false;
+
+ /* Since we attempt to modify the SYSTEM registry after it's extracted
+ * (see end_wimboot_extraction()), it can't be extracted as externally
+ * backed. This extends to associated files such as SYSTEM.LOG that
+ * also must be writable in order to write to the registry. Normally,
+ * SYSTEM is in [PrepopulateList], and the SYSTEM.* files match patterns
+ * in [ExclusionList] and therefore are not captured in the WIM at all.
+ * However, a WIM that wasn't specifically captured in "WIMBoot mode"
+ * may contain SYSTEM.* files. So to make things "just work", hard-code
+ * the pattern. */
+ if (match_path(path, path_nchars, L"\\Windows\\System32\\config\\SYSTEM*",
+ OS_PREFERRED_PATH_SEPARATOR, false))
+ return false;
+
+ return true;