[05/11] libnsdb: Handle LDAP referrals correctly

diff --git a/src/include/nsdb.h b/src/include/nsdb.h
index 030b1d2..2895433 100644
--- a/src/include/nsdb.h
+++ b/src/include/nsdb.h
@@ -181,6 +181,11 @@  FedFsStatus	 nsdb_lookup_nsdb(const char *hostname,
 				struct fedfs_secdata *sec);
 
 /**
+ * Instantiate an nsdb_t object based on stored connection parameters
+ */
+FedFsStatus	 nsdb_lookup_nsdb_by_uri(const char *uri, nsdb_t *host);
+
+/**
  * Update stored connection parameters for an NSDB
  */
 FedFsStatus	 nsdb_update_nsdb(const char *hostname,
@@ -240,6 +245,7 @@  unsigned short	 nsdb_port(const nsdb_t host);
 const char	*nsdb_default_binddn(const nsdb_t host);
 const char	*nsdb_default_nce(const nsdb_t host);
 _Bool		 nsdb_follow_referrals(const nsdb_t host);
+const char	*nsdb_referred_to(const nsdb_t host);
 
 /**
  * Data type helpers for nsdb_t objects
diff --git a/src/libnsdb/fileserver.c b/src/libnsdb/fileserver.c
index cdceb37..362e056 100644
--- a/src/libnsdb/fileserver.c
+++ b/src/libnsdb/fileserver.c
@@ -137,6 +137,9 @@  __nsdb_search_nsdb_attr_s(const char *func, LDAP *ld, const char *base,
 void
 nsdb_free_fedfs_fsn(struct fedfs_fsn *fsn)
 {
+	if (fsn == NULL)
+		return;
+
 	nsdb_free_string_array(fsn->fn_description);
 	nsdb_free_string_array(fsn->fn_annotations);
 	free(fsn->fn_dn);
@@ -397,6 +400,7 @@  nsdb_get_ncedn_s(nsdb_t host, const char *naming_context, char **dn,
 						"fedfsNceDN", &response);
 	switch (rc) {
 	case LDAP_SUCCESS:
+	case LDAP_REFERRAL:
 		break;
 	case LDAP_NO_SUCH_OBJECT:
 		xlog(D_GENERAL, "%s: %s is not an NSDB container entry",
@@ -415,20 +419,12 @@  nsdb_get_ncedn_s(nsdb_t host, const char *naming_context, char **dn,
 	}
 
 	rc = ldap_count_messages(ld, response);
-	switch (rc) {
-	case -1:
+	if (rc == -1) {
 		xlog(D_GENERAL, "%s: Empty LDAP response\n", __func__);
 		retval = FEDFS_ERR_NSDB_FAULT;
 		goto out;
-	case 1:
-		xlog(L_ERROR, "Naming context entry %s is inaccessible",
-			naming_context);
-		retval = FEDFS_ERR_NSDB_NONCE;
-		goto out;
-	default:
-		xlog(D_CALL, "%s: received %d messages", __func__, rc);
-		break;
 	}
+	xlog(D_CALL, "%s: received %d messages", __func__, rc);
 
 	tmp = NULL;
 	retval = FEDFS_OK;
@@ -440,7 +436,9 @@  nsdb_get_ncedn_s(nsdb_t host, const char *naming_context, char **dn,
 			retval = nsdb_parse_ncedn_entry(ld, message, &tmp);
 			break;
 		case LDAP_RES_SEARCH_RESULT:
-			retval = nsdb_parse_result(ld, message, NULL, ldap_err);
+			retval = nsdb_parse_result(ld, message,
+							&host->fn_referrals,
+							ldap_err);
 			break;
 		default:
 			xlog(L_ERROR, "%s: Unrecognized LDAP message type",
@@ -1001,7 +999,7 @@  nsdb_resolve_fsn_parse_entry(LDAP *ld, LDAPMessage *entry,
 /**
  * Retrieve and display the FSL entries associated with an FSN UUID
  *
- * @param ld an initialized LDAP server descriptor
+ * @param host an initialized and bound nsdb_t object
  * @param nce a NUL-terminated C string containing DN of NSDB container entry
  * @param fsn_uuid a NUL-terminated C string containing FSN UUID
  * @param fsls OUT: a list of fedfs_fsl structures
@@ -1017,10 +1015,11 @@  nsdb_resolve_fsn_parse_entry(LDAP *ld, LDAPMessage *entry,
    @endverbatim
  */
 static FedFsStatus
-nsdb_resolve_fsn_find_entry_s(LDAP *ld, const char *nce, const char *fsn_uuid,
+nsdb_resolve_fsn_find_entry_s(nsdb_t host, const char *nce, const char *fsn_uuid,
 		struct fedfs_fsl **fsls, unsigned int *ldap_err)
 {
 	LDAPMessage *response, *message;
+	LDAP *ld = host->fn_ldap;
 	struct fedfs_fsl *tmp;
 	FedFsStatus retval;
 	char filter[128];
@@ -1038,6 +1037,7 @@  nsdb_resolve_fsn_find_entry_s(LDAP *ld, const char *nce, const char *fsn_uuid,
 						filter, &response);
 	switch (rc) {
 	case LDAP_SUCCESS:
+	case LDAP_REFERRAL:
 		break;
 	case LDAP_NO_SUCH_OBJECT:
 		xlog(D_GENERAL, "%s: No entry for FSN UUID %s exists",
@@ -1055,20 +1055,12 @@  nsdb_resolve_fsn_find_entry_s(LDAP *ld, const char *nce, const char *fsn_uuid,
 	}
 
 	rc = ldap_count_messages(ld, response);
-	switch (rc) {
-	case -1:
+	if (rc == -1) {
 		xlog(D_GENERAL, "%s: Empty LDAP response", __func__);
 		ldap_msgfree(response);
 		return FEDFS_ERR_NSDB_FAULT;
-	case 1:
-		xlog(D_CALL, "%s: No FSL entries for FSN UUID %s",
-			__func__, fsn_uuid);
-		ldap_msgfree(response);
-		return FEDFS_ERR_NSDB_NOFSL;
-	default:
-		xlog(D_CALL, "%s: Received %d messages", __func__, rc);
-		break;
 	}
+	xlog(D_CALL, "%s: Received %d messages", __func__, rc);
 
 	tmp = NULL;
 	retval = FEDFS_OK;
@@ -1081,7 +1073,9 @@  nsdb_resolve_fsn_find_entry_s(LDAP *ld, const char *nce, const char *fsn_uuid,
 							message, &tmp);
 			break;
 		case LDAP_RES_SEARCH_RESULT:
-			retval = nsdb_parse_result(ld, message, NULL, ldap_err);
+			retval = nsdb_parse_result(ld, message,
+							&host->fn_referrals,
+							ldap_err);
 			break;
 		default:
 			xlog(L_ERROR, "%s: Unrecognized LDAP message type",
@@ -1092,8 +1086,14 @@  nsdb_resolve_fsn_find_entry_s(LDAP *ld, const char *nce, const char *fsn_uuid,
 	ldap_msgfree(response);
 
 	if (retval == FEDFS_OK) {
-		xlog(D_CALL, "%s: returning fsls", __func__);
-		*fsls = tmp;
+		if (tmp == NULL) {
+			xlog(D_CALL, "%s: No FSL entries for FSN UUID %s",
+				__func__, fsn_uuid);
+			retval = FEDFS_ERR_NSDB_NOFSL;
+		} else {
+			xlog(D_CALL, "%s: returning fsls", __func__);
+			*fsls = tmp;
+		}
 	} else
 		nsdb_free_fedfs_fsls(tmp);
 	return retval;
@@ -1132,7 +1132,7 @@  nsdb_resolve_fsn_s(nsdb_t host, const char *nce, const char *fsn_uuid,
 	}
 
 	if (nce != NULL)
-		return nsdb_resolve_fsn_find_entry_s(host->fn_ldap, nce,
+		return nsdb_resolve_fsn_find_entry_s(host, nce,
 						fsn_uuid, fsls, ldap_err);
 
 	/*
@@ -1163,9 +1163,9 @@  nsdb_resolve_fsn_s(nsdb_t host, const char *nce, const char *fsn_uuid,
 		goto out;
 
 	for (j = 0; nce_list[j] != NULL; j++) {
-		retval = nsdb_resolve_fsn_find_entry_s(host->fn_ldap,
-							nce_list[j], fsn_uuid,
-							fsls, ldap_err);
+		retval = nsdb_resolve_fsn_find_entry_s(host, nce_list[j],
+							fsn_uuid, fsls,
+							ldap_err);
 		if (retval == FEDFS_OK)
 			break;
 	}
@@ -1310,7 +1310,7 @@  nsdb_get_fsn_parse_entry(LDAP *ld, LDAPMessage *entry,
 /**
  * Retrieve an FSN entry associated with an FSN UUID
  *
- * @param ld an initialized LDAP server descriptor
+ * @param host an initialized and bound nsdb_t object
  * @param nce a NUL-terminated C string containing DN of NSDB container entry
  * @param fsn_uuid a NUL-terminated C string containing FSN UUID
  * @param fsn OUT: a fedfs_fsn structures
@@ -1328,10 +1328,11 @@  nsdb_get_fsn_parse_entry(LDAP *ld, LDAPMessage *entry,
    @endverbatim
  */
 static FedFsStatus
-nsdb_get_fsn_find_entry_s(LDAP *ld, const char *nce, const char *fsn_uuid,
+nsdb_get_fsn_find_entry_s(nsdb_t host, const char *nce, const char *fsn_uuid,
 		struct fedfs_fsn **fsn, unsigned int *ldap_err)
 {
 	LDAPMessage *response, *message;
+	LDAP *ld = host->fn_ldap;
 	struct fedfs_fsn *tmp;
 	FedFsStatus retval;
 	char filter[128];
@@ -1349,6 +1350,7 @@  nsdb_get_fsn_find_entry_s(LDAP *ld, const char *nce, const char *fsn_uuid,
 						filter, &response);
 	switch (rc) {
 	case LDAP_SUCCESS:
+	case LDAP_REFERRAL:
 		break;
 	case LDAP_NO_SUCH_OBJECT:
 		xlog(D_GENERAL, "%s: No FSN record for FSN UUID %s exists",
@@ -1366,20 +1368,12 @@  nsdb_get_fsn_find_entry_s(LDAP *ld, const char *nce, const char *fsn_uuid,
 	}
 
 	rc = ldap_count_messages(ld, response);
-	switch (rc) {
-	case -1:
+	if (rc == -1) {
 		xlog(D_GENERAL, "%s: Empty LDAP response", __func__);
 		ldap_msgfree(response);
 		return FEDFS_ERR_NSDB_FAULT;
-	case 1:
-		xlog(D_GENERAL, "%s: No FSN record for FSN UUID %s exists",
-			__func__, fsn_uuid);
-		ldap_msgfree(response);
-		return FEDFS_ERR_NSDB_NOFSN;
-	default:
-		xlog(D_CALL, "%s: Received %d messages", __func__, rc);
-		break;
 	}
+	xlog(D_CALL, "%s: Received %d messages", __func__, rc);
 
 	tmp = NULL;
 	retval = FEDFS_OK;
@@ -1391,7 +1385,9 @@  nsdb_get_fsn_find_entry_s(LDAP *ld, const char *nce, const char *fsn_uuid,
 			retval = nsdb_get_fsn_parse_entry(ld, message, &tmp);
 			break;
 		case LDAP_RES_SEARCH_RESULT:
-			retval = nsdb_parse_result(ld, message, NULL, ldap_err);
+			retval = nsdb_parse_result(ld, message,
+							&host->fn_referrals,
+							ldap_err);
 			break;
 		default:
 			xlog(L_ERROR, "%s: Unrecognized LDAP message type",
@@ -1442,8 +1438,8 @@  nsdb_get_fsn_s(nsdb_t host, const char *nce, const char *fsn_uuid,
 	}
 
 	if (nce != NULL)
-		return nsdb_get_fsn_find_entry_s(host->fn_ldap, nce,
-						fsn_uuid, fsn, ldap_err);
+		return nsdb_get_fsn_find_entry_s(host, nce, fsn_uuid,
+							fsn, ldap_err);
 
 	/*
 	 * Caller did not provide an nce.  Generate a list
@@ -1473,8 +1469,7 @@  nsdb_get_fsn_s(nsdb_t host, const char *nce, const char *fsn_uuid,
 		goto out;
 
 	for (j = 0; nce_list[j] != NULL; j++) {
-		retval = nsdb_get_fsn_find_entry_s(host->fn_ldap,
-							nce_list[j], fsn_uuid,
+		retval = nsdb_get_fsn_find_entry_s(host, nce_list[j], fsn_uuid,
 							fsn, ldap_err);
 		if (retval == FEDFS_OK)
 			break;
@@ -1571,7 +1566,7 @@  nsdb_parse_fsn_entry(LDAP *ld, LDAPMessage *entry, char ***fsns)
 /**
  * Retrieve and display the FSN entries associated with an NSDB container
  *
- * @param ld an initialized LDAP server descriptor
+ * @param host an initialized and bound nsdb_t object
  * @param nce a NUL-terminated C string containing the DN of the NSDB container
  * @param fsns OUT: pointer to an array of NUL-terminated C strings containing FSN UUIDs
  * @param ldap_err OUT: possibly an LDAP error code
@@ -1585,10 +1580,11 @@  nsdb_parse_fsn_entry(LDAP *ld, LDAPMessage *entry, char ***fsns)
    @endverbatim
  */
 static FedFsStatus
-nsdb_list_find_entries_s(LDAP *ld, const char *nce, char ***fsns,
+nsdb_list_find_entries_s(nsdb_t host, const char *nce, char ***fsns,
 		unsigned int *ldap_err)
 {
 	LDAPMessage *response, *message;
+	LDAP *ld = host->fn_ldap;
 	FedFsStatus retval;
 	char **tmp;
 	int rc;
@@ -1597,6 +1593,7 @@  nsdb_list_find_entries_s(LDAP *ld, const char *nce, char ***fsns,
 					"(objectClass=fedfsFsn)", &response);
 	switch (rc) {
 	case LDAP_SUCCESS:
+	case LDAP_REFERRAL:
 		break;
 	case LDAP_NO_SUCH_OBJECT:
 		xlog(D_GENERAL, "%s: No entry for %s exists",
@@ -1614,21 +1611,12 @@  nsdb_list_find_entries_s(LDAP *ld, const char *nce, char ***fsns,
 	}
 
 	rc = ldap_count_messages(ld, response);
-	switch (rc) {
-	case -1:
+	if (rc == -1) {
 		xlog(D_GENERAL, "%s: Empty LDAP response", __func__);
 		ldap_msgfree(response);
 		return FEDFS_ERR_NSDB_FAULT;
-	case 1:
-		xlog(D_CALL, "%s: No FSN entries under %s",
-			__func__, nce);
-		ldap_msgfree(response);
-		return FEDFS_ERR_NSDB_NOFSN;
-	default:
-		xlog(D_CALL, "%s: Received %d messages",
-			__func__, rc);
-		break;
 	}
+	xlog(D_CALL, "%s: Received %d messages", __func__, rc);
 
 	/* Assume one FSN per LDAP message, minus the RESULT message,
 	 * plus the NULL pointer on the end of the array */
@@ -1647,7 +1635,9 @@  nsdb_list_find_entries_s(LDAP *ld, const char *nce, char ***fsns,
 			retval = nsdb_parse_fsn_entry(ld, message, &tmp);
 			break;
 		case LDAP_RES_SEARCH_RESULT:
-			retval = nsdb_parse_result(ld, message, NULL, ldap_err);
+			retval = nsdb_parse_result(ld, message,
+							&host->fn_referrals,
+							ldap_err);
 			break;
 		default:
 			xlog(L_ERROR, "%s: Unrecognized LDAP message type",
@@ -1657,8 +1647,14 @@  nsdb_list_find_entries_s(LDAP *ld, const char *nce, char ***fsns,
 	}
 
 	if (retval == FEDFS_OK) {
-		xlog(D_CALL, "%s: returning fsn list", __func__);
-		*fsns = tmp;
+		if (tmp[0] == NULL) {
+			xlog(D_CALL, "%s: No FSN entries under %s",
+				__func__, nce);
+			retval = FEDFS_ERR_NSDB_NOFSN;
+		} else {
+			xlog(D_CALL, "%s: returning fsn list", __func__);
+			*fsns = tmp;
+		}
 	} else
 		nsdb_free_string_array(tmp);
 
@@ -1696,8 +1692,7 @@  nsdb_list_s(nsdb_t host, const char *nce, char ***fsns, unsigned int *ldap_err)
 	}
 
 	if (nce != NULL)
-		return nsdb_list_find_entries_s(host->fn_ldap, nce,
-							fsns, ldap_err);
+		return nsdb_list_find_entries_s(host, nce, fsns, ldap_err);
 
 	/*
 	 * Caller did not provide an nce.  Discover the server's NSDB
@@ -1728,9 +1723,8 @@  nsdb_list_s(nsdb_t host, const char *nce, char ***fsns, unsigned int *ldap_err)
 		goto out;
 
 	for (j = 0; nce_list[j] != NULL; j++) {
-		retval = nsdb_list_find_entries_s(host->fn_ldap,
-							nce_list[j],
-							fsns, ldap_err);
+		retval = nsdb_list_find_entries_s(host, nce_list[j],
+						fsns, ldap_err);
 		if (retval == FEDFS_OK)
 			break;
 	}
diff --git a/src/libnsdb/ldap.c b/src/libnsdb/ldap.c
index 8b4291e..e5e2133 100644
--- a/src/libnsdb/ldap.c
+++ b/src/libnsdb/ldap.c
@@ -803,6 +803,7 @@  nsdb_copy_referrals_array(char **refs, char ***referrals)
 	}
 	tmp[i] = NULL;
 
+	nsdb_free_string_array(*referrals);
 	*referrals = tmp;
 	return FEDFS_OK;
 }
diff --git a/src/libnsdb/nsdb-internal.h b/src/libnsdb/nsdb-internal.h
index 55b146f..6cf96c9 100644
--- a/src/libnsdb/nsdb-internal.h
+++ b/src/libnsdb/nsdb-internal.h
@@ -45,6 +45,7 @@  struct fedfs_nsdb {
 	char *			fn_default_binddn;
 	char *			fn_default_nce;
 	_Bool			fn_follow_referrals;
+	char **			fn_referrals;
 };
 
 /**
diff --git a/src/libnsdb/nsdb.c b/src/libnsdb/nsdb.c
index 46b7845..20d9e55 100644
--- a/src/libnsdb/nsdb.c
+++ b/src/libnsdb/nsdb.c
@@ -378,6 +378,22 @@  nsdb_follow_referrals(const nsdb_t host)
 }
 
 /**
+ * Return NSDB's default NCE
+ *
+ * @param host an instantiated nsdb_t object
+ * @return a NUL-terminated UTF-8 string containing an LDAP URI
+ *
+ * Lifetime of this string is the same as the lifetime of the
+ * nsdb_t.  Caller must not free this string, and must not use
+ * it after the nsdb_t is freed.
+ */
+const char *
+nsdb_referred_to(const nsdb_t host)
+{
+	return host->fn_referrals[0];
+}
+
+/**
  * Retrieve NSDB-related environment variables
  *
  * @param nsdbname OUT: pointer to statically allocated NUL-terminated C string containing NSDB hostname
@@ -1126,6 +1142,55 @@  nsdb_lookup_nsdb(const char *hostname, const unsigned short port,
 }
 
 /**
+ * Read NSDB info from NSDB database, using LDAP URI
+ *
+ * @param uri NUL-terminated ASCII string containing an LDAP URI
+ * @param host OUT: an initialized nsdb_t object
+ * @return a FedFsStatus code
+ *
+ * On success, FEDFS_OK is returned and a fresh nsdb_t is returned.
+ *
+ * Caller must free "host" with nsdb_free_nsdb().
+ */
+FedFsStatus
+nsdb_lookup_nsdb_by_uri(const char *uri, nsdb_t *host)
+{
+	FedFsStatus retval;
+	LDAPURLDesc *lud;
+	nsdb_t new;
+	int rc;
+
+	rc = ldap_url_parse(uri, &lud);
+	if (rc != LDAP_URL_SUCCESS) {
+		xlog(D_GENERAL, "%s: Failed to parse URI %s", __func__, uri);
+		return FEDFS_ERR_INVAL;
+	}
+
+	if (lud->lud_scheme == NULL ||
+	    strcasecmp(lud->lud_scheme, "ldap") != 0) {
+		xlog(D_GENERAL, "%s: Invalid URI %s", __func__, uri);
+		retval = FEDFS_ERR_INVAL;
+		goto out;
+	}
+
+	xlog(D_CALL, "%s: Looking up NSDB %s:%u",
+		__func__, lud->lud_host, lud->lud_port);
+	retval = nsdb_new_nsdb(lud->lud_host, lud->lud_port, &new);
+	if (retval != FEDFS_OK)
+		goto out;
+
+	retval = nsdb_read_nsdbparams(new, NULL);
+	if (retval != FEDFS_OK)
+		nsdb_free_nsdb(new);
+	else
+		*host = new;
+
+out:
+	ldap_free_urldesc(lud);
+	return retval;
+}
+
+/**
  * Update connection parameters for an NSDB
  *
  * @param host an instantiated nsdb_t object
@@ -1510,6 +1575,8 @@  nsdb_close_nsdb(nsdb_t host)
 {
 	(void)ldap_unbind_ext_s(host->fn_ldap, NULL, NULL);
 	host->fn_ldap = NULL;
+	nsdb_free_string_array(host->fn_referrals);
+	host->fn_referrals = NULL;
 }
 
 /**