Related to bug #217, added command 'fail accept <errno>' to debug client's commands.

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'

server/core/gateway.c

@@ -216,6 +216,8 @@ memset(dcb_fake_write_errno, 0, sizeof(unsigned char)*1024);
 memset(dcb_fake_write_ev, 0, sizeof(__int32_t)*1024);
 fail_next_backend_fd = false;
 fail_next_client_fd = false;
+fail_next_accept = false;
+fail_accept_errno = 0;
 #endif
         l = atexit(skygw_logmanager_exit);
 

server/include/dcb.h

@@ -190,6 +190,8 @@ unsigned char dcb_fake_write_errno[1024];
 __int32_t     dcb_fake_write_ev[1024];
 bool          fail_next_backend_fd;
 bool          fail_next_client_fd;
+bool          fail_next_accept;
+int           fail_accept_errno;
 #endif
 
 /* A few useful macros */

server/modules/protocol/mysql_client.c

@@ -127,7 +127,11 @@ mysql_send_ok(DCB *dcb, int packet_number, int in_affected_rows, const char* mys
 
         affected_rows = in_affected_rows;
 	
-	mysql_payload_size = sizeof(field_count) + sizeof(affected_rows) + sizeof(insert_id) + sizeof(mysql_server_status) + sizeof(mysql_warning_count);
+	mysql_payload_size = sizeof(field_count) +
+                sizeof(affected_rows) +
+                sizeof(insert_id) +
+                sizeof(mysql_server_status) +
+                sizeof(mysql_warning_count);
 
         if (mysql_message != NULL) {
                 mysql_payload_size += strlen(mysql_message);
@@ -513,7 +517,6 @@ int gw_read_client_event(DCB* dcb) {
         int             rc = 0;
 
         CHK_DCB(dcb);
-
         protocol = DCB_PROTOCOL(dcb, MySQLProtocol);
         CHK_PROTOCOL(protocol);
         /**
@@ -611,7 +614,6 @@ int gw_read_client_event(DCB* dcb) {
                  * Read all the data that is available into a chain of buffers
                  */
         {
-                /* int      len; */
                 GWBUF   *queue = NULL;
                 GWBUF   *gw_buffer = NULL;
                 uint8_t *ptr_buff = NULL;
@@ -639,34 +641,20 @@ int gw_read_client_event(DCB* dcb) {
                 /* Now, we are assuming in the first buffer there is
                  * the information form mysql command */
                 queue = gw_buffer;
-                 /* len = GWBUF_LENGTH(queue); */
                 ptr_buff = GWBUF_DATA(queue);
                 
                 /* get mysql commang at fifth byte */
                 if (ptr_buff) {
                         mysql_command = ptr_buff[4];
                 }
-
-                if (mysql_command  == '\x03') {
                 /**
-                         * SQL Trace here.
+                 * Without rsession there is no access to backend.
-                         * Length can be calculated and it must be passed as
+                 * COM_QUIT : close client dcb
-                         * argument.
+                 * else     : write custom error to client dcb.
                  */
-                        /* this is a standard MySQL query !!!! */
-                }
-                /**
-                 * Routing Client input to Backend
-                 */
-                /* Do not route the query without session! */
                 if(rsession == NULL) {
+                        /** COM_QUIT */
                         if (mysql_command == '\x01') {
-                                /**
-                                 * COM_QUIT handling
-                                 *
-                                 * fprintf(stderr, "COM_QUIT received with
-                                 * no connected backends from %i\n", dcb->fd);
-                                 */
                                 skygw_log_write_flush(
                                         LOGFILE_DEBUG,
                                         "%lu [gw_read_client_event] Client read "
@@ -682,63 +670,52 @@ int gw_read_client_event(DCB* dcb) {
                                         dcb,
                                         1,
                                         0,
-                                        "Connection to backend lost");
+                                        "Query routing failed. Connection to "
+                                        "backend lost");
                                 protocol->state = MYSQL_IDLE;
                         }
                         rc = 1;
                         goto return_rc;
                 }
-                /* We can route the query */		
+                /** Route COM_QUIT to backend */
-                /* COM_QUIT handling */
                 if (mysql_command == '\x01') {
-                        skygw_log_write_flush(
-                                LOGFILE_DEBUG,
-                                "%lu [gw_read_client_event] Before routeQuery. "
-                                "dcb %p.",
-                                pthread_self(),
-                                dcb);                        
-                        /**
-                         * fprintf(stderr, "COM_QUIT received from %i and
-                         * passed to backed\n", dcb->fd);
-                         * this will propagate COM_QUIT to backend(s)
-                         * fprintf(stderr, "<<< Routing the COM_QUIT ...\n");
-                         */
                         router->routeQuery(router_instance, rsession, queue);
                         skygw_log_write_flush(
                                 LOGFILE_DEBUG,
-                                "%lu [gw_read_client_event] After routeQuery. "
+                                "%lu [gw_read_client_event] Routed COM_QUIT to "
-                                "dcb %p.",
+                                "backend. Close client dcb %p",
                                 pthread_self(),
                                 dcb);
                         
-                        /* close client connection */
+                        /** close client connection */
+                        
                         (dcb->func).close(dcb);                        
                         rc = 1;
-                        goto return_rc;
                 }
-
+                else
-                /* MySQL Command Routing */
+                {
+                        /** Route other commands to backend */
                         protocol->state = MYSQL_ROUTING;
-
-                /* writing in the backend buffer queue, via routeQuery */
-                //fprintf(stderr, "<<< Routing the Query ...\n");
                         rc = router->routeQuery(router_instance, rsession, queue);
-
+                        /** succeed */
                         if (rc == 1) {
                                 protocol->state = MYSQL_WAITING_RESULT;
+                                rc = 0; /**< here '0' means success */
                         } else {
                                 mysql_send_custom_error(dcb,
                                                         1,
                                                         0,
-                                                "Connection to backend lost.");
+                                                        "Query routing failed. "
+                                                        "Connection to backend "
+                                                        "lost.");
                                 protocol->state = MYSQL_IDLE;
+                        }
+                }
                 goto return_rc;
-                }
+        } /*  MYSQL_IDLE, MYSQL_WAITING_RESULT */
-        }
         break;
         
         default:
-                // todo
                 break;
 	}
         rc = 0;
@@ -950,6 +927,15 @@ int gw_MySQLAccept(DCB *listener)
                                 &addrlen);
 
                 eno = errno;
+#if defined(SS_DEBUG)
+                if (fail_next_accept) {
+                        c_sock = -1;
+                        eno = fail_accept_errno;
+                        i = 10;
+                        fail_next_accept = false;
+                        fail_accept_errno = 0;
+                }
+#endif /* SS_DEBUG */
                         
                 if (c_sock == -1) {
                         
@@ -1105,9 +1091,9 @@ int gw_MySQLAccept(DCB *listener)
                 CHK_PROTOCOL(protocol);
         }
 #endif
-return_rc:
+        return_rc:
                 return rc;
-}
+        }
 
 /*
 */

server/modules/routing/debugcmd.c

@@ -43,6 +43,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <errno.h>
 #include <service.h>
 #include <session.h>
 #include <router.h>
@@ -189,10 +190,21 @@ static void disable_log_action(DCB *, char *);
  *  * The subcommands of the enable command
  *   */
 struct subcommand enableoptions[] = {
-        { "log",        1, enable_log_action,   "Enable Log options for MaxScale, options trace | error | message E.g. enable log message.",
+        {
-                                {ARG_TYPE_STRING, 0, 0} },
+                "log",
-        { NULL,         0, NULL,                NULL,
+                1,
-                                {0, 0, 0} }
+                enable_log_action,
+                "Enable Log options for MaxScale, options trace | error | "
+                "message E.g. enable log message.",
+                {ARG_TYPE_STRING, 0, 0}
+        },
+        {
+                NULL,
+                0,
+                NULL,
+                NULL,
+                {0, 0, 0}
+        }
 };
 
 
@@ -200,17 +212,28 @@ struct subcommand enableoptions[] = {
  *  * The subcommands of the disable command
  *   */
 struct subcommand disableoptions[] = {
-    { "log",        1, disable_log_action,  "Disable Log for MaxScale, Options: trace | error | message E.g. disable log trace",
+    {
-      {ARG_TYPE_STRING, 0, 0} },
+            "log",
-    { NULL,         0, NULL,                NULL,
+            1,
-      {0, 0, 0} }
+            disable_log_action,
+            "Disable Log for MaxScale, Options: trace | error | message E.g. "
+            "disable log trace",
+            {ARG_TYPE_STRING, 0, 0}
+    },
+    {
+            NULL,
+            0,
+            NULL,
+            NULL,
+            {0, 0, 0}
+    }
 };
 
 #if defined(SS_DEBUG)
 
 static void fail_backendfd(void);
 static void fail_clientfd(void);
-
+static void fail_accept(DCB* dcb, char* arg1);
 /**
  *  * The subcommands of the fail command
  *   */
@@ -229,6 +252,13 @@ struct subcommand failoptions[] = {
         "Fail client socket for next operation.",
         {ARG_TYPE_STRING, 0, 0}
     },
+    {
+        "accept",
+        1,
+        fail_accept,
+        "Fail to accept next client connection.",
+        {ARG_TYPE_STRING, 0, 0}
+    },
     {
         NULL,
         0,
@@ -735,11 +765,42 @@ static void disable_log_action(DCB *dcb, char *arg1) {
 #if defined(SS_DEBUG)
 static void fail_backendfd(void)
 { 
-        fail_next_backend_fd = TRUE;
+        fail_next_backend_fd = true;
 }
 
 static void fail_clientfd(void)
 { 
-        fail_next_client_fd = TRUE;
+        fail_next_client_fd = true;
+}
+
+static void fail_accept(
+        DCB*  dcb,
+        char* arg1)
+{
+        fail_accept_errno = atoi(arg1);
+
+        switch(fail_accept_errno) {
+                case EAGAIN:
+//                case EWOULDBLOCK:
+                case EBADF:
+                case EINTR:
+                case EINVAL:
+                case EMFILE:
+                case ENFILE:
+                case ENOTSOCK:
+                case EOPNOTSUPP:
+                case ENOBUFS:
+                case ENOMEM:
+                case EPROTO:
+                        fail_next_accept = true;
+        break;
+
+                default:
+                        dcb_printf(dcb,
+                                   "[%d, %s] is not valid errno for accept.\n",
+                                   fail_accept_errno,
+                                   strerror(fail_accept_errno));
+                return ;
+        }
 }
 #endif