+ if (mc && strcmp(mc->m.mnt_type, "nfs") != 0 &&
+ strcmp(mc->m.mnt_type, "nfs4") != 0) {
+ nfs_error(_("%s: %s on %s is not an NFS filesystem"),
+ progname, mc->m.mnt_fsname, mc->m.mnt_dir);
+ return EX_USAGE;
+ }
+
+ if (getuid() != 0) {
+ /* only permitted if "user=" or "users" is in mount options */
+ if (!mc) {
+ /* umount might call us twice. The second time there will
+ * be no entry in mtab and we should just exit quietly
+ */
+ return EX_SUCCESS;
+
+ only_root:
+ nfs_error(_("%s: You are not permitted to unmount %s"),
+ progname, spec);
+ return EX_USAGE;
+ }
+ if (hasmntopt(&mc->m, "users") == NULL) {
+ char *opt = hasmntopt(&mc->m, "user");
+ struct passwd *pw;
+ char *comma;
+ int len;
+ if (!opt)
+ goto only_root;
+ if (opt[4] != '=')
+ goto only_root;
+ comma = strchr(opt, ',');
+ if (comma)
+ len = comma - (opt + 5);
+ else
+ len = strlen(opt+5);
+ pw = getpwuid(getuid());
+ if (pw == NULL || strlen(pw->pw_name) != len
+ || strncmp(pw->pw_name, opt+5, len) != 0)
+ goto only_root;
+ }
+ }
+
+ ret = 0;