WL#2936 - Falcon & MySQL plugin interface: server variables

Added initialization for the plugin structure created in
plugin_add().
Made a correct argument vector in mysql_install_plugin():
handle_options() assumes that arg0 (program name) always exists.


mysys/my_getopt.c:
  WL#2936 - Falcon & MySQL plugin interface: server variables
  Added DBUG_ASSERTs. handle_options() assumes that arg0
  (program name) always exists.
plugin/fulltext/plugin_example.c:
  WL#2936 - Falcon & MySQL plugin interface: server variables
  Extended the fulltext parser example plugin with system variables.

mysys/my_getopt.c

@@ -111,6 +111,9 @@ int handle_options(int *argc, char ***argv,
   int error, i;
 
   LINT_INIT(opt_found);
+  /* handle_options() assumes arg0 (program name) always exists */
+  DBUG_ASSERT(argc && *argc >= 1);
+  DBUG_ASSERT(argv && *argv);
   (*argc)--; /* Skip the program name */
   (*argv)++; /*      --- || ----      */
   init_variables(longopts);

plugin/fulltext/plugin_example.c

@@ -215,6 +215,29 @@ static struct st_mysql_show_var simple_status[]=
   {0,0,0}
 };
 
+/*
+  Plugin system variables.
+*/
+
+static long     sysvar_one_value;
+static char     *sysvar_two_value;
+
+static MYSQL_SYSVAR_LONG(simple_sysvar_one, sysvar_one_value,
+  PLUGIN_VAR_RQCMDARG,
+  "Simple fulltext parser example system variable number one. Give a number.",
+  NULL, NULL, 100L, 10L, ~0L, 0);
+
+static MYSQL_SYSVAR_STR(simple_sysvar_two, sysvar_two_value,
+  PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_MEMALLOC,
+  "Simple fulltext parser example system variable number two. Give a string.",
+  NULL, NULL, NULL);
+
+static struct st_mysql_sys_var* simple_system_variables[]= {
+  MYSQL_SYSVAR(simple_sysvar_one),
+  MYSQL_SYSVAR(simple_sysvar_two),
+  NULL
+};
+
 /*
   Plugin library descriptor
 */
@@ -231,8 +254,8 @@ mysql_declare_plugin(ftexample)
   simple_parser_plugin_deinit,/* deinit function (when unloaded) */
   0x0001,                     /* version                         */
   simple_status,              /* status variables                */
-  NULL,                       /* system variables                */
-  NULL                        /* config options                  */
+  simple_system_variables,    /* system variables                */
+  NULL
 }
 mysql_declare_plugin_end;
 

sql/sql_plugin.cc

@@ -701,6 +701,8 @@ static bool plugin_add(MEM_ROOT *tmp_root,
       sql_print_error(ER(ER_UDF_EXISTS), name->str);
     DBUG_RETURN(TRUE);
   }
+  /* Clear the whole struct to catch future extensions. */
+  bzero((char*) &tmp, sizeof(tmp));
   if (! (tmp.plugin_dl= plugin_dl_add(dl, report)))
     DBUG_RETURN(TRUE);
   /* Find plugin by name */
@@ -1569,7 +1571,8 @@ bool mysql_install_plugin(THD *thd, const LEX_STRING *name, const LEX_STRING *dl
 {
   TABLE_LIST tables;
   TABLE *table;
-  int error, argc=0;
+  int error, argc;
+  char *argv[2];
   struct st_plugin_int *tmp;
   DBUG_ENTER("mysql_install_plugin");
 
@@ -1585,7 +1588,10 @@ bool mysql_install_plugin(THD *thd, const LEX_STRING *name, const LEX_STRING *dl
 
   pthread_mutex_lock(&LOCK_plugin);
   rw_wrlock(&LOCK_system_variables_hash);
-  error= plugin_add(thd->mem_root, name, dl, &argc, NULL, REPORT_TO_USER);
+  argv[0]= ""; /* handle_options() assumes arg0 (program name) always exists */
+  argv[1]= NULL;
+  argc= 1;
+  error= plugin_add(thd->mem_root, name, dl, &argc, argv, REPORT_TO_USER);
   rw_unlock(&LOCK_system_variables_hash);
 
   if (error || !(tmp= plugin_find_internal(name, MYSQL_ANY_PLUGIN)))