Reproduce #217 by connecting with telnet to debug client interface and execute command:
fail accept 23
and try to execute read query, for example, with
mysql -h 127.0.0.1 -P 4008 -u maxuser -pmaxpwd -e 'select current_user(), @@server_id'
dcb_final_free: Router session is not closed anymore when dcb is closed. Router session is shared among all dcbs and is closed and freed with session.
dcb_connect: dcb's state must be switched fro DCB_STATE_ALLOC to DCB_STATE_DISCONNECTED before dcb_final_free can be called for it.
dcb_close: poll_remove_dcb encapsulates dcb's state transition in the same way as poll_add_dcb. Removed state modification from dcb_close. Read return value of poll_remove_dcb and log accordingly.
dcb_set state: remove dassert if dcb_set_state_nomutex returned false. False can be returned indicating that intented change didn't occur but the end state, for example, may be acceptable. Failures in state transitions are asserted in dcb_Set_state_nomutex.
poll.c
poll_add_dcb: dcb state is now set here to either DCB_STATE_LISTENING or to DCB_STATE_POLLING according to dcb's role. Failures in state setting and in epoll_ctl are detected, logged and handled.
poll_remove_dcb: Failures in state setting and epoll_ctl are detected, logged, and handled.
mysql_client_server_protocol.h
Removed macros MYSQL_FAILED_AUTHENTICATION & MYSQL_SUCCESFUL_AUTHENTICATION as they were not necessary and used with constant values 0 and 1 depending on the case.
Renamed variable 'conn' to 'protocol' in cases where it meant protocol.
mysql_backend.c
gw_read_backend_event: In case when there was nothing to read or read failed, backend dcb is closed because situation is assumed to be such that backend server closed its side of the socket. Removed macros MYSQL_FAILED/SUCCESFUL_AUTHENTICATION
gw_create_backend_connection: Assigned protocol with fd which is connected to backend.
backend_write_delayqueue: In case where dcb_write fails to write anything, close backend dcb to avoid it getting hanging.
mysql_client.c
gw_read_client_event: Read return value of routeQuery and if it isn't == 1, call mysql_send_custom_error with client dcb and set client's protocol state to MYSQL_IDLE instead of MYSQL_ROUTING.
gw_MySQLAccept: Static reply counter was erroneously used as a criteria for jumping to return point where return value was constantly 'success' (=0). Replaced static reply counter with private. Fixed return value in different cases.
mysql_common.c
gw_receive_backend_auth: Changed to return boolean values indicating of success or failue. Used integers which were assigned to macroed values on the caller side. Added length check before accessing buffer.
readconnroute.c
Cut too long lines and removed statements with side effects.
skygw_debug.h
Added macro STRPROTOCOLSTATE(s) to produce string representation of a given protocol state.
If backend connection can't be created, backend_dcb is not create, router client session is not created and what already is created in session_alloc, is freed.
mysql_client.c : gw_read_client_event
If session creation failed, then - instead of sending ok to client, "failed to create new session" is sent and client dcb is closed.
: gw_MySQLAccept
removed loop where accept was called again and again. With single thread looping forever is not possible because there's no one to free previously allocated resources.
If accept fails ten times in a row, then return without new client dcb.
: dcb_alloc switched malloc to calloc, dcb->fd is initialized to -1.
: dcb_process_zombies return value of close(fd) is checked. Closed fds are stored to conn_open array.
: dcb_connect assigns new fd only if backend connection succeeds. Dcb is added to poll set in the same way, only if connect succeed.
gateway.c : conn_open array is initialized in main. For each created socket, a true is set to corresponding slot. Max. number of slots is 1024.
mysql_client_server_protocol.h : gw_do_connect_to declaration
mysql_backend.c : gw_create_backend_connection returns rv >= 0 and a protocol which is assigned to backend_dcb. In error, -1 is returned and fd is not set.
mysql_client.c : conn_open array is kept up-to-date and protocol pointer is assigned also to dcb outside mysql_protocol_init.
mysql_common.c : gw_do_connect_to_backend 3rd argument is pointer to fd, not protocol. dcb is added to poll set later in dcb_connect.
skygw_debug.h : define conn_open[1024] array where open connections can be marked in debug build.
session.c: Replaced free(session->router_sesision) with call to freeSession callback
users.c: Removed reference to uninitialized variable.
router.h: Added freeSession callback to function block.
mysql_backend.c: try to ensure that client dcb is still listening in epoll_wait when writing reply to it.
mysql_common.c: assert debug build is mysql_protocol_init is called with dcb == NULL
readconnroute.c, readwritesplit.c, debugcli.c and testroute.c : Added freeSession to function block and an inmplementation of it.
Removed freeing router session object because it is not know at this phase whether session is really closed or not. Router session can be freed only when session is.
