Implement account login support

This is done via the `accountname' METADATA command and used to
automatically identify users after netsplits or across service
restarts.

doc/Protocol.txt

@@ -224,6 +224,7 @@ new server link", <serverflag> "M"), even if it doesn't support the given
 
 The following <key> names are defined:
 
+ - "accountname": the account name of a client (can't be empty)
  - "host": the hostname of a client (can't be empty)
  - "cloakhost": the cloaked hostname of a client
  - "info": info text ("real name") of a client

src/ngircd/client.c

@@ -124,6 +124,8 @@ Client_Exit( void )
 	{
 		cnt++;
 		next = (CLIENT *)c->next;
+		if (c->account_name)
+			free(c->account_name);
 		free( c );
 		c = next;
 	}
@@ -318,6 +320,8 @@ Client_Destroy( CLIENT *Client, const char *LogMsg, const char *FwdMsg, bool Sen
 				}
 			}
 
+			if (c->account_name)
+				free(c->account_name);
 			if (c->cloaked)
 				free(c->cloaked);
 			free( c );
@@ -454,6 +458,21 @@ Client_SetFlags( CLIENT *Client, const char *Flags )
 } /* Client_SetFlags */
 
 
+GLOBAL void
+Client_SetAccountName(CLIENT *Client, const char *AccountName)
+{
+	assert(Client != NULL);
+
+	if (Client->account_name)
+		free(Client->account_name);
+
+	if (*AccountName)
+		Client->account_name = strdup(AccountName);
+	else
+		Client->account_name = NULL;
+}
+
+
 GLOBAL void
 Client_SetAway( CLIENT *Client, const char *Txt )
 {
@@ -973,6 +992,14 @@ Client_Away( CLIENT *Client )
 } /* Client_Away */
 
 
+GLOBAL char *
+Client_AccountName(CLIENT *Client)
+{
+	assert(Client != NULL);
+	return Client->account_name;
+}
+
+
 /**
  * Make sure that a given nickname is valid.
  *
@@ -1611,6 +1638,14 @@ Client_Announce(CLIENT * Client, CLIENT * Prefix, CLIENT * User)
 				return DISCONNECTED;
 		}
 
+		if (Client_AccountName(User)) {
+			if (!IRC_WriteStrClientPrefix(Client, Prefix,
+					"METADATA %s accountname :%s",
+					Client_ID(User),
+					Client_AccountName(User)))
+				return DISCONNECTED;
+		}
+
 		if (Conn_GetCertFp(Client_Conn(User))) {
 			if (!IRC_WriteStrClientPrefix(Client, Prefix,
 					"METADATA %s certfp :%s",

src/ngircd/client.h

@@ -59,6 +59,7 @@ typedef struct _CLIENT
 	bool oper_by_me;		/* client is local IRC operator on this server? */
 	char away[CLIENT_AWAY_LEN];	/* AWAY text (valid if mode 'a' is set) */
 	char flags[CLIENT_FLAGS_LEN];	/* flags of the client */
+	char *account_name;		/* login account (for services) */
 	int capabilities;		/* enabled IRC capabilities */
 } CLIENT;
 
@@ -123,6 +124,7 @@ GLOBAL int Client_MyToken PARAMS(( CLIENT *Client ));
 GLOBAL CLIENT *Client_TopServer PARAMS(( CLIENT *Client ));
 GLOBAL CLIENT *Client_NextHop PARAMS(( CLIENT *Client ));
 GLOBAL char *Client_Away PARAMS(( CLIENT *Client ));
+GLOBAL char *Client_AccountName PARAMS((CLIENT *Client));
 GLOBAL time_t Client_StartTime PARAMS(( CLIENT *Client ));
 
 GLOBAL bool Client_HasMode PARAMS(( CLIENT *Client, char Mode ));
@@ -141,6 +143,7 @@ GLOBAL void Client_SetModes PARAMS(( CLIENT *Client, const char *Modes ));
 GLOBAL void Client_SetFlags PARAMS(( CLIENT *Client, const char *Flags ));
 GLOBAL void Client_SetIntroducer PARAMS(( CLIENT *Client, CLIENT *Introducer ));
 GLOBAL void Client_SetAway PARAMS(( CLIENT *Client, const char *Txt ));
+GLOBAL void Client_SetAccountName PARAMS((CLIENT *Client, const char *AccountName));
 
 GLOBAL bool Client_ModeAdd PARAMS(( CLIENT *Client, char Mode ));
 GLOBAL bool Client_ModeDel PARAMS(( CLIENT *Client, char Mode ));

src/ngircd/irc-metadata.c

@@ -96,6 +96,8 @@ IRC_METADATA(CLIENT *Client, REQUEST *Req)
 		Client_SetInfo(target, Req->argv[2]);
 	else if (*Req->argv[2] && strcasecmp(Req->argv[1], "user") == 0)
 		Client_SetUser(target, Req->argv[2], true);
+	else if (strcasecmp(Req->argv[1], "accountname") == 0)
+		Client_SetAccountName(target, Req->argv[2]);
 	else if (*Req->argv[2] && strcasecmp(Req->argv[1], "certfp") == 0)
 		Conn_SetCertFp(Client_Conn(target), Req->argv[2]);
 	else