Specify when a mysql_users.max_connections is reached #794

It also fixes:
* bug in deps/Makefile related to cleanall
* crashing bug in HGCU_thread_run()

deps/Makefile

@@ -84,13 +84,13 @@ pcre: pcre/pcre/.libs/libpcre.a
 
 cleanpart:
 	cd mariadb-client-library && rm -rf mariadb-connector-c-2.3.1
-	cd jemalloc && rm -rf jemalloc-4.1.0
+	cd jemalloc && rm -rf jemalloc-4.2.1
 	cd sqlite3/sqlite3 && rm -rf *
 .PHONY: cleanpart
 
 cleanall:
 	cd libdaemon && rm -rf libdaemon-0.14
-	cd jemalloc && rm -rf jemalloc-4.1.0
+	cd jemalloc && rm -rf jemalloc-4.2.1
 	cd mariadb-client-library && rm -rf mariadb-connector-c-2.3.1
 	cd libconfig && rm -rf libconfig-1.4.9
 	cd re2 && rm -rf re2

include/MySQL_Authentication.hpp

@@ -64,7 +64,7 @@ class MySQL_Authentication {
 	void print_version();
 	char * lookup(char *username, enum cred_username_type usertype, bool *use_ssl, int *default_hostgroup, char **default_schema, bool *schema_locked, bool *transaction_persistent, bool *fast_forward, int *max_connections, void **sha1_pass);
 	int dump_all_users(account_details_t ***);
-	int increase_frontend_user_connections(char *username);
+	int increase_frontend_user_connections(char *username, int *mc=NULL);
 	void decrease_frontend_user_connections(char *username);
 	void set_all_inactive(enum cred_username_type usertype);
 	void remove_inactives(enum cred_username_type usertype);

lib/MySQL_Authentication.cpp

@@ -255,7 +255,7 @@ __exit_dump_all_users:
 }
 
 
-int MySQL_Authentication::increase_frontend_user_connections(char *username) {
+int MySQL_Authentication::increase_frontend_user_connections(char *username, int *mc) {
 	uint64_t hash1, hash2;
 	SpookyHash *myhash=new SpookyHash();
 	myhash->Init(1,2);
@@ -272,6 +272,9 @@ int MySQL_Authentication::increase_frontend_user_connections(char *username) {
 		account_details_t *ad=it->second;
 		ad->num_connections_used++;
 		ret=ad->max_connections-ad->num_connections_used;
+		if (mc) {
+			*mc=ad->max_connections;
+		}
 	}
 	spin_wrunlock(&cg.lock);
 	return ret;

lib/MySQL_HostGroups_Manager.cpp

@@ -45,7 +45,12 @@ static void * HGCU_thread_run() {
 		int i;
 		for (i=0;i<(int)l;i++) {
 			myconn=(MySQL_Connection *)conn_array->index(i);
-			statuses[i]=mysql_change_user_start(&ret[i], myconn->mysql, myconn->userinfo->password, myconn->userinfo->password, myconn->userinfo->schemaname);
+			if (myconn->mysql->net.vio) {
+				statuses[i]=mysql_change_user_start(&ret[i], myconn->mysql, myconn->userinfo->password, myconn->userinfo->password, myconn->userinfo->schemaname);
+			} else {
+				statuses[i]=0;
+				ret[i]=1;
+			}
 		}
 		for (i=0;i<(int)conn_array->len;i++) {
 			if (statuses[i]==0) {

lib/MySQL_Session.cpp

@@ -2562,15 +2562,25 @@ void MySQL_Session::handler___status_CONNECTING_CLIENT___STATE_SERVER_HANDSHAKE(
 				client_myds->myconn->userinfo->set_schemaname(default_schema,strlen(default_schema));
 			}
 			int free_users=0;
+			int used_users=0;
 			if (admin==false) {
 				client_authenticated=true;
-				free_users=GloMyAuth->increase_frontend_user_connections(client_myds->myconn->userinfo->username);
+				free_users=GloMyAuth->increase_frontend_user_connections(client_myds->myconn->userinfo->username, &used_users);
 			}
 			if (max_connections_reached==true || free_users<0) {
-				proxy_debug(PROXY_DEBUG_MYSQL_CONNECTION, 5, "Too many connections\n");
 				*wrong_pass=true;
 				client_myds->setDSS_STATE_QUERY_SENT_NET();
-				client_myds->myprot.generate_pkt_ERR(true,NULL,NULL,2,1040,(char *)"#HY000", (char *)"Too many connections");
+				if (max_connections_reached==true) {
+					proxy_debug(PROXY_DEBUG_MYSQL_CONNECTION, 5, "Too many connections\n");
+					client_myds->myprot.generate_pkt_ERR(true,NULL,NULL,2,1040,(char *)"08004", (char *)"Too many connections");
+				} else { // see issue #794
+					proxy_debug(PROXY_DEBUG_MYSQL_CONNECTION, 5, "User '%s' has exceeded the 'max_user_connections' resource (current value: %d)\n", client_myds->myconn->userinfo->username, used_users);
+					char *a=(char *)"User '%s' has exceeded the 'max_user_connections' resource (current value: %d)";
+					char *b=(char *)malloc(strlen(a)+strlen(client_myds->myconn->userinfo->username)+16);
+					sprintf(b,a,client_myds->myconn->userinfo->username,used_users);
+					client_myds->myprot.generate_pkt_ERR(true,NULL,NULL,2,1226,(char *)"42000", b);
+					free(b);
+				}
 				__sync_add_and_fetch(&MyHGM->status.client_connections_aborted,1);
 				client_myds->DSS=STATE_SLEEP;
 			} else {