+/**
+ * dedupsubkeys - Merge duplicate subkeys on a key.
+ * @key: The key to de-dup subkeys on.
+ *
+ * This function attempts to merge duplicate subkeys on a key. It returns
+ * 0 if the key is unchanged, otherwise the number of dups merged.
+ */
+int dedupsubkeys(struct openpgp_publickey *key)
+{
+ struct openpgp_signedpacket_list *cursubkey = NULL;
+ struct openpgp_signedpacket_list *dup = NULL;
+ struct openpgp_signedpacket_list *tmp = NULL;
+ int merged = 0;
+ uint64_t subkeyid;
+
+ log_assert(key != NULL);
+ cursubkey = key->subkeys;
+ while (cursubkey != NULL) {
+ dup = find_signed_packet(cursubkey->next, cursubkey->packet);
+ while (dup != NULL) {
+ get_packetid(cursubkey->packet, &subkeyid);
+ logthing(LOGTHING_INFO,
+ "Found duplicate subkey: 0x%016" PRIX64,
+ subkeyid);
+ merged++;
+ merge_packet_sigs(cursubkey, dup);
+ /*
+ * Remove the duplicate uid.
+ */
+ tmp = cursubkey;
+ while (tmp != NULL && tmp->next != dup) {
+ tmp = tmp->next;
+ }
+ log_assert(tmp != NULL);
+ tmp->next = dup->next;
+ dup->next = NULL;
+ free_signedpacket_list(dup);
+
+ dup = find_signed_packet(cursubkey->next,
+ cursubkey->packet);
+ }
+ cursubkey = cursubkey->next;
+ }
+
+ return merged;
+}
+