dcb.h

-------
Removed DCB states DCB_STATE_IDLE, and DCB_STATE_PROCESSING.
Added DCB_STATE_UNDEFINED for initial content for state variable which doesn't have any specific value set, and DCB_STATE_NOPOLLING to indicate that dcb has been removed from poll set.

Added following dcb roles: DCB_ROLE_SERVICE_LISTENER for listeners of services, and DCB_ROLE_REQUEST_HANDLER for client/backend dcbs. Listeners may have state DCB_STATE_LISTENING, but not DCB_STATE_POLLING. Request handlers may have DCB_STATE_POLLING but not DCB_STATE_LISTENING. Role is passed as an argument to dcb.c:dcb_alloc.

From now on, struct check numbers of DCB are included and checked in DEBUG build only.

Added dcb_role_t dcb_role-member to DCB as well as SPINLOCK dcb_initlock, which protects state changes.

Removed extern keyword from function declarations because functions are by default externally visible if they are declared in header.

dcb.b
------
Function dcb_set_state, and dcb_set_state_nomutex provide functions for changing dcb states. Latter implements a state machine for dcb.
Function dcb_add_to_zombieslist replaces dcb_free. It adds in atomic step dcb to zombieslist and changes state to DCB_STATE_ZOMBIE.
Function dcb_final_free removes dcb from allDCBs list, terminates router and client sessions, and frees dcb and related memory.
Function dcb_process_zombies removes executing thread from dcb's bitmask, and it there are no further thread bits, moves dcb to a victim list, and finally, for each dcb on victim list, closes fd and sets state to DCB_STATE_DISCONNECTED.
Function dcb_close sets dcb state to DCB_STATE_NOPOLLIN, removes dcb from poll set and sets bit to bitmask for each server thread in an atomic step.  

poll.c
------
Function poll_add_dcb sets either DCB_STATE_LISTENING or DCB_STATE_POLLING state for newly created dcb, depending whether the role of dcb is DCB_ROLE_SERVICE_LISTENER, or DCB_ROLE_REQUEST_HANDLER, respectively. Then dcb is set to poll set.

poll_waitevents : commented out code which skipped event if dcb was added to zombieslist or if fd was closed. Added state checks.

service.c : Minor changes.
httpd.c : Removed dcb state changes. They are done in core.
mysql_backend.c : Added checks, removed dcb state changes.
mysql_client.c : Removed dcb state changes. Added checks.
mysql_common.c : Minor changes
telnetd.c : Removed state changes. Replaced some typecasts and pointer references with local variable reads.
skygw_debug.h : Removed two states, and added two to state printing macro.

server/modules/protocol/mysql_common.c

@@ -71,44 +71,6 @@ return_p:
         return p;
 }
 
-#if 0
-/**
- * gw_mysql_init
- *
- * Initialize mysql protocol struct
- *
- * @param data The MySQLProtocol pointer, usually NULL
- * @return The new MySQLProtocol allocated
- *
- */
-
-MySQLProtocol *gw_mysql_init(MySQLProtocol *data) {
-        MySQLProtocol *input = NULL;
-
-        // structure allocation
-        input = calloc(1, sizeof(MySQLProtocol));
-        
-        if (input == NULL) {
-            int eno = errno;
-            errno = 0;
-            skygw_log_write_flush(
-                    LOGFILE_ERROR,
-                    "%lu [gw_mysql_init] failed to allocate memory for MySQL "
-                    "protocol object. Errno %d, %s.",
-                    pthread_self(),
-                    eno,
-                    strerror(eno));
-            return NULL;
-        }
-        input->protocol_chk_top = CHK_NUM_PROTOCOL;
-        input->protocol_chk_tail = CHK_NUM_PROTOCOL;
-                
-#ifdef MYSQL_CONN_DEBUG
-	fprintf(stderr, "gw_mysql_init() called\n");
-#endif
-        return input;
-}
-#endif 
 
 /**
  * gw_mysql_close
@@ -502,7 +464,10 @@ int gw_do_connect_to_backend(
 	struct sockaddr_in serv_addr;
 	int rv;
 	int so = 0;
+        DCB* dcb = conn->descriptor;
 
+        CHK_DCB(dcb);
+        
 	memset(&serv_addr, 0, sizeof serv_addr);
 	serv_addr.sin_family = AF_INET;
 	so = socket(AF_INET,SOCK_STREAM,0);
@@ -513,8 +478,9 @@ int gw_do_connect_to_backend(
                 errno = 0;
                 skygw_log_write_flush(
                         LOGFILE_ERROR,
-                        "%lu [gw_do_connect_to_backend] Establishing connection to "
-                        "back-end server failed. Socket creation failed due %d, %s.",
+                        "%lu [gw_do_connect_to_backend] Establishing connection "
+                        "to back-end server failed. Socket creation failed due "
+                        "%d, %s.",
                         pthread_self(),
                         eno,
                         strerror(eno));
@@ -522,7 +488,7 @@ int gw_do_connect_to_backend(
                 goto return_rv;
 	}
 	/* Assign so to the caller dcb, conn->descriptor */
-	conn->descriptor->fd = so;
+	dcb->fd = so;
 	/* prepare for connect */
 	setipaddress(&serv_addr.sin_addr, host);
 	serv_addr.sin_port = htons(port);
@@ -552,7 +518,7 @@ int gw_do_connect_to_backend(
         /**
          * Add the dcb in the poll set
          */
-        poll_add_dcb(conn->descriptor);
+        poll_add_dcb(dcb);
 return_rv:
 	return rv;
 }
@@ -1007,7 +973,6 @@ int gw_find_mysql_user_password_sha1(char *username, uint8_t *gateway_password,
 
         if (strlen(user_password))
                 gw_hex2bin(gateway_password, user_password, SHA_DIGEST_LENGTH * 2);
-
         return 0;
 }
 
@@ -1089,4 +1054,3 @@ mysql_send_auth_error (DCB *dcb, int packet_number, int in_affected_rows, const
 
         return sizeof(mysql_packet_header) + mysql_payload_size;
 }
-///