- if (*buf) {
- if (!*cwd && !getcwd(cwd, sizeof(cwd)))
- die ("Could not get current working directory");
+/*
+ * path = Canonical absolute path
+ * prefix_list = Colon-separated list of absolute paths
+ *
+ * Determines, for each path in parent_list, whether the "prefix" really
+ * is an ancestor directory of path. Returns the length of the longest
+ * ancestor directory, excluding any trailing slashes, or -1 if no prefix
+ * is an ancestor. (Note that this means 0 is returned if prefix_list is
+ * "/".) "/foo" is not considered an ancestor of "/foobar". Directories
+ * are not considered to be their own ancestors. path must be in a
+ * canonical form: empty components, or "." or ".." components are not
+ * allowed. prefix_list may be null, which is like "".
+ */
+int longest_ancestor_length(const char *path, const char *prefix_list)
+{
+ char buf[PATH_MAX+1];
+ const char *ceil, *colon;
+ int len, max_len = -1;