Abstract the session default database

The default database can now be manipulated with a set of functions
exposed by the maxscale/protocol/mysql.h header. This removes the need to
handle the structures themselves in the modules and is a step towards
moving the dcb->data contents inside the session.

server/modules/filter/cache/CMakeLists.txt

@@ -17,7 +17,7 @@ if (JANSSON_FOUND)
     storagefactory.cc
     storagereal.cc
     )
-  target_link_libraries(cache maxscale-common ${JANSSON_LIBRARIES})
+  target_link_libraries(cache maxscale-common ${JANSSON_LIBRARIES} MySQLCommon)
   set_target_properties(cache PROPERTIES VERSION "1.0.0")
   set_target_properties(cache PROPERTIES LINK_FLAGS -Wl,-z,defs)
   install_module(cache core)

server/modules/filter/cache/cachefiltersession.cc

@@ -205,15 +205,15 @@ CacheFilterSession* CacheFilterSession::Create(Cache* pCache, MXS_SESSION* pSess
     ss_dassert(pSession->client_dcb);
     ss_dassert(pSession->client_dcb->data);
 
-    MYSQL_session *pMysqlSession = (MYSQL_session*)pSession->client_dcb->data;
+    const char* zDb = mxs_mysql_get_current_db(pSession);
     char* zDefaultDb = NULL;
 
-    if (pMysqlSession->db[0] != 0)
+    if (zDb[0] != 0)
     {
-        zDefaultDb = MXS_STRDUP(pMysqlSession->db);
+        zDefaultDb = MXS_STRDUP(zDb);
     }
 
-    if ((pMysqlSession->db[0] == 0) || zDefaultDb)
+    if ((zDb[0] == 0) || zDefaultDb)
     {
         pCacheFilterSession = new (std::nothrow) CacheFilterSession(pSession, pCache, zDefaultDb);
 

server/modules/filter/dbfwfilter/CMakeLists.txt

@@ -7,13 +7,13 @@ if(BISON_FOUND AND FLEX_FOUND)
   include_directories(${CMAKE_CURRENT_BINARY_DIR})
   include_directories(${CMAKE_CURRENT_SOURCE_DIR})
   add_library(dbfwfilter SHARED dbfwfilter.c ${BISON_ruleparser_OUTPUTS} ${FLEX_token_OUTPUTS})
-  target_link_libraries(dbfwfilter maxscale-common)
+  target_link_libraries(dbfwfilter maxscale-common MySQLCommon)
   set_target_properties(dbfwfilter PROPERTIES VERSION "1.0.0")
   install_module(dbfwfilter core)
 
   # The offline rule check utility
   add_executable(dbfwchk dbfw_rule_check.c ${BISON_ruleparser_OUTPUTS} ${FLEX_token_OUTPUTS})
-  target_link_libraries(dbfwchk maxscale-common)
+  target_link_libraries(dbfwchk maxscale-common MySQLCommon)
   install_executable(dbfwchk core)
 
 else()

server/modules/filter/dbfwfilter/dbfwfilter.c

@@ -1745,7 +1745,7 @@ GWBUF* gen_dummy_error(FW_SESSION* session, char* msg)
     }
 
     dcb = session->session->client_dcb;
-    mysql_session = (MYSQL_session*) dcb->data;
+    const char* db = mxs_mysql_get_current_db(session->session);
     errlen = msg != NULL ? strlen(msg) : 0;
     errmsg = (char*) MXS_MALLOC((512 + errlen) * sizeof(char));
 
@@ -1755,14 +1755,14 @@ GWBUF* gen_dummy_error(FW_SESSION* session, char* msg)
     }
 
 
-    if (mysql_session->db[0] == '\0')
+    if (db[0] == '\0')
     {
         sprintf(errmsg, "Access denied for user '%s'@'%s'", dcb->user, dcb->remote);
     }
     else
     {
         sprintf(errmsg, "Access denied for user '%s'@'%s' to database '%s'",
-                dcb->user, dcb->remote, mysql_session->db);
+                dcb->user, dcb->remote, db);
     }
 
     if (msg != NULL)

server/modules/filter/mqfilter/mqfilter.c

@@ -807,21 +807,15 @@ void pushMessage(MQ_INSTANCE *instance, amqp_basic_properties_t* prop, char* msg
 static MXS_FILTER_SESSION *
 newSession(MXS_FILTER *instance, MXS_SESSION *session)
 {
-    MYSQL_session *sessauth = session->client_dcb->data;
-    char *db = sessauth->db;
-    if (db)
+    const char *db = mxs_mysql_get_current_db(session);
+    char* my_db = NULL;
+
+    if (*db)
     {
-        if (strnlen(db, 128) > 0)
+        my_db = MXS_STRDUP(my_db);
+        if (!my_db)
         {
-            db = MXS_STRDUP(db);
-            if (!db)
-            {
-                return NULL;
-            }
-        }
-        else
-        {
-            db = NULL;
+            return NULL;
         }
     }
 
@@ -832,11 +826,11 @@ newSession(MXS_FILTER *instance, MXS_SESSION *session)
         my_session->was_query = false;
         my_session->uid = NULL;
         my_session->session = session;
-        my_session->db = db;
+        my_session->db = my_db;
     }
     else
     {
-        MXS_FREE(db);
+        MXS_FREE(my_db);
     }
 
     return (MXS_FILTER_SESSION*)my_session;