- if (chdir(buf))
- die ("Could not switch to '%s'", buf);
- }
- if (!getcwd(buf, PATH_MAX))
- die ("Could not get current working directory");
-
- if (last_elem) {
- int len = strlen(buf);
- if (len + strlen(last_elem) + 2 > PATH_MAX)
- die ("Too long path name: '%s/%s'",
- buf, last_elem);
- buf[len] = '/';
- strcpy(buf + len + 1, last_elem);
- free(last_elem);
- last_elem = NULL;
- }
+/*
+ * 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;