+/*
+ * Convert the passed-in sockaddr-style address to presentation
+ * format, then append an option of the form "keyword=address".
+ *
+ * Returns 1 if the option was appended successfully; otherwise zero.
+ */
+static int nfs_append_generic_address_option(const struct sockaddr *sap,
+ const socklen_t salen,
+ const char *keyword,
+ struct mount_options *options)
+{
+ char address[NI_MAXHOST];
+ char new_option[512];
+ int len;
+
+ if (!nfs_present_sockaddr(sap, salen, address, sizeof(address)))
+ goto out_err;
+
+ len = snprintf(new_option, sizeof(new_option), "%s=%s",
+ keyword, address);
+ if (len < 0 || (size_t)len >= sizeof(new_option))
+ goto out_err;
+
+ if (po_append(options, new_option) != PO_SUCCEEDED)
+ goto out_err;
+
+ return 1;
+
+out_err:
+ nfs_error(_("%s: failed to construct %s option"), progname, keyword);
+ return 0;
+}
+
+/*
+ * Append the 'addr=' option to the options string to pass a resolved
+ * server address to the kernel. After a successful mount, this address
+ * is also added to /etc/mtab for use when unmounting.
+ *
+ * If 'addr=' is already present, we strip it out. This prevents users
+ * from setting a bogus 'addr=' option themselves, and also allows bg
+ * retries to recompute the server's address, in case it has changed.
+ *
+ * Returns 1 if 'addr=' option appended successfully;
+ * otherwise zero.
+ */
+static int nfs_append_addr_option(const struct sockaddr *sap,
+ socklen_t salen,
+ struct mount_options *options)
+{
+ po_remove_all(options, "addr");
+ return nfs_append_generic_address_option(sap, salen, "addr", options);