allow plugins to set flags

include/mysql/plugin.h

@@ -98,6 +98,9 @@ typedef struct st_mysql_xid MYSQL_XID;
 #define MYSQL_AUTHENTICATION_PLUGIN  7
 #define MYSQL_MAX_PLUGIN_TYPE_NUM    12  /**< The number of plugin types */
 
+#define MYSQL_PLUGIN_TYPE_MASK     ((1<<16)-1)
+#define MYSQL_AUTH_CAN_BE_DEFAULT  (1<<16)
+
 /* MariaDB plugin types */
 /** Client and server password validation */
 #define MariaDB_PASSWORD_VALIDATION_PLUGIN  8 
@@ -565,7 +568,22 @@ struct st_mysql_plugin
 
 struct st_maria_plugin
 {
+#ifdef __cplusplus
+  struct alignas(sizeof(int)) auth_type_t
+  {
+    int raw_version;
+    auth_type_t() = default;
+    auth_type_t(int version): raw_version(version){}
+    operator int() const
+    { return raw_version & MYSQL_PLUGIN_TYPE_MASK; }
+    int flags() const
+    { return raw_version & ~MYSQL_PLUGIN_TYPE_MASK; }
+  };
+
+  auth_type_t type;     /**< the plugin type (a MYSQL_XXX_PLUGIN value)   */
+#else
   int type;             /**< the plugin type (a MYSQL_XXX_PLUGIN value)   */
+#endif
   void *info;           /**< pointer to type-specific plugin descriptor   */
   const char *name;     /**< plugin name                                  */
   const char *author;   /**< plugin author (for SHOW PLUGINS)             */

include/mysql/plugin_audit.h.pp

@@ -569,7 +569,17 @@ struct st_mysql_plugin
 };
 struct st_maria_plugin
 {
-  int type;
+  struct alignas(sizeof(int)) auth_type_t
+  {
+    int raw_version;
+    auth_type_t() = default;
+    auth_type_t(int version): raw_version(version){}
+    operator int() const
+    { return raw_version & ((1<<16)-1); }
+    int flags() const
+    { return raw_version & ~((1<<16)-1); }
+  };
+  auth_type_t type;
   void *info;
   const char *name;
   const char *author;

include/mysql/plugin_auth.h.pp

@@ -569,7 +569,17 @@ struct st_mysql_plugin
 };
 struct st_maria_plugin
 {
-  int type;
+  struct alignas(sizeof(int)) auth_type_t
+  {
+    int raw_version;
+    auth_type_t() = default;
+    auth_type_t(int version): raw_version(version){}
+    operator int() const
+    { return raw_version & ((1<<16)-1); }
+    int flags() const
+    { return raw_version & ~((1<<16)-1); }
+  };
+  auth_type_t type;
   void *info;
   const char *name;
   const char *author;

include/mysql/plugin_data_type.h.pp

@@ -569,7 +569,17 @@ struct st_mysql_plugin
 };
 struct st_maria_plugin
 {
-  int type;
+  struct alignas(sizeof(int)) auth_type_t
+  {
+    int raw_version;
+    auth_type_t() = default;
+    auth_type_t(int version): raw_version(version){}
+    operator int() const
+    { return raw_version & ((1<<16)-1); }
+    int flags() const
+    { return raw_version & ~((1<<16)-1); }
+  };
+  auth_type_t type;
   void *info;
   const char *name;
   const char *author;

include/mysql/plugin_encryption.h.pp

@@ -569,7 +569,17 @@ struct st_mysql_plugin
 };
 struct st_maria_plugin
 {
-  int type;
+  struct alignas(sizeof(int)) auth_type_t
+  {
+    int raw_version;
+    auth_type_t() = default;
+    auth_type_t(int version): raw_version(version){}
+    operator int() const
+    { return raw_version & ((1<<16)-1); }
+    int flags() const
+    { return raw_version & ~((1<<16)-1); }
+  };
+  auth_type_t type;
   void *info;
   const char *name;
   const char *author;

include/mysql/plugin_ftparser.h.pp

@@ -569,7 +569,17 @@ struct st_mysql_plugin
 };
 struct st_maria_plugin
 {
-  int type;
+  struct alignas(sizeof(int)) auth_type_t
+  {
+    int raw_version;
+    auth_type_t() = default;
+    auth_type_t(int version): raw_version(version){}
+    operator int() const
+    { return raw_version & ((1<<16)-1); }
+    int flags() const
+    { return raw_version & ~((1<<16)-1); }
+  };
+  auth_type_t type;
   void *info;
   const char *name;
   const char *author;

include/mysql/plugin_function.h.pp

@@ -569,7 +569,17 @@ struct st_mysql_plugin
 };
 struct st_maria_plugin
 {
-  int type;
+  struct alignas(sizeof(int)) auth_type_t
+  {
+    int raw_version;
+    auth_type_t() = default;
+    auth_type_t(int version): raw_version(version){}
+    operator int() const
+    { return raw_version & ((1<<16)-1); }
+    int flags() const
+    { return raw_version & ~((1<<16)-1); }
+  };
+  auth_type_t type;
   void *info;
   const char *name;
   const char *author;

include/mysql/plugin_password_validation.h.pp

@@ -569,7 +569,17 @@ struct st_mysql_plugin
 };
 struct st_maria_plugin
 {
-  int type;
+  struct alignas(sizeof(int)) auth_type_t
+  {
+    int raw_version;
+    auth_type_t() = default;
+    auth_type_t(int version): raw_version(version){}
+    operator int() const
+    { return raw_version & ((1<<16)-1); }
+    int flags() const
+    { return raw_version & ~((1<<16)-1); }
+  };
+  auth_type_t type;
   void *info;
   const char *name;
   const char *author;

plugin/auth_parsec/server_parsec.cc

@@ -294,7 +294,7 @@ static struct st_mysql_auth info =
 
 maria_declare_plugin(auth_parsec)
 {
-  MYSQL_AUTHENTICATION_PLUGIN,
+  MYSQL_AUTHENTICATION_PLUGIN|MYSQL_AUTH_CAN_BE_DEFAULT,
   &info,
   "parsec",
   "Nikita Maliavin",

sql/sql_acl.cc

@@ -2549,6 +2549,15 @@ bool acl_init(bool dont_read_acl_tables)
   if (!native_password_plugin || !old_password_plugin || !default_auth_plugin)
     DBUG_RETURN(1);
 
+  st_plugin_int *default_auth_int= plugin_ref_to_int(default_auth_plugin);
+  if (!(default_auth_int->plugin->type.flags() & MYSQL_AUTH_CAN_BE_DEFAULT))
+  {
+    sql_print_error("Error: plugin %s cannot be set as default.",
+                    default_auth_int->name.str);
+    DBUG_RETURN(1);
+  }
+
+
   if (dont_read_acl_tables)
   {
     DBUG_RETURN(0); /* purecov: tested */
@@ -15362,7 +15371,8 @@ static struct st_mysql_auth old_password_handler=
 
 maria_declare_plugin(mysql_password)
 {
-  MYSQL_AUTHENTICATION_PLUGIN,                  /* type constant    */
+  MYSQL_AUTHENTICATION_PLUGIN | MYSQL_AUTH_CAN_BE_DEFAULT,
+                                                /* type constant    */
   &native_password_handler,                     /* type descriptor  */
   native_password_plugin_name.str,              /* Name             */
   "R.J.Silk, Sergei Golubchik",                 /* Author           */
@@ -15377,7 +15387,8 @@ maria_declare_plugin(mysql_password)
   MariaDB_PLUGIN_MATURITY_STABLE                /* Maturity         */
 },
 {
-  MYSQL_AUTHENTICATION_PLUGIN,                  /* type constant    */
+  MYSQL_AUTHENTICATION_PLUGIN | MYSQL_AUTH_CAN_BE_DEFAULT,
+                                                /* type constant    */
   &old_password_handler,                        /* type descriptor  */
   old_password_plugin_name.str,                 /* Name             */
   "R.J.Silk, Sergei Golubchik",                 /* Author           */