WL#5341 - Sticky plugins

This patch implements "permanent" load option for
plugins as specified by WL#5341.

mysql-test/r/plugin_load_option.result:
  A test case for WL#5341.
mysql-test/t/plugin_load_option-master.opt:
  A test case for WL#5341.
mysql-test/t/plugin_load_option.test:
  A test case for WL#5341.
sql/share/errmsg-utf8.txt:
  An error message for WL#5341.
sql/sql_plugin.cc:
  Added FORCE_PLUS_PERMANENT plugin load option.
sql/sql_plugin.h:
  Expose and use plugin load option instead of
  is_mandatory flag. This is a requirement for
  to-be-implemented WL5496.

6 files changed, 42 insertions, 16 deletions

diff --git a/mysql-test/r/plugin_load_option.result b/mysql-test/r/plugin_load_option.result
new file mode 100644
index 00000000000..3e49e3c6b47
--- /dev/null
+++ b/mysql-test/r/plugin_load_option.result
@@ -0,0 +1,2 @@
+UNINSTALL PLUGIN example;
+ERROR HY000: Plugin 'example' is force_plus_permanent and can not be unloaded
diff --git a/mysql-test/t/plugin_load_option-master.opt b/mysql-test/t/plugin_load_option-master.opt
new file mode 100644
index 00000000000..3be53c3b713
--- /dev/null
+++ b/mysql-test/t/plugin_load_option-master.opt
@@ -0,0 +1,3 @@
+$EXAMPLE_PLUGIN_OPT
+$EXAMPLE_PLUGIN_LOAD
+--plugin-example=FORCE_PLUS_PERMANENT
diff --git a/mysql-test/t/plugin_load_option.test b/mysql-test/t/plugin_load_option.test
new file mode 100644
index 00000000000..604be30b561
--- /dev/null
+++ b/mysql-test/t/plugin_load_option.test
@@ -0,0 +1,5 @@
+--source include/not_windows_embedded.inc
+--source include/have_example_plugin.inc
+
+--error ER_PLUGIN_IS_PERMANENT
+UNINSTALL PLUGIN example;
diff --git a/sql/share/errmsg-utf8.txt b/sql/share/errmsg-utf8.txt
index 9e7fdbfeae5..b01b824f236 100644
--- a/sql/share/errmsg-utf8.txt
+++ b/sql/share/errmsg-utf8.txt
@@ -6346,3 +6346,5 @@ ER_STORED_FUNCTION_PREVENTS_SWITCH_SQL_LOG_BIN
 ER_FAILED_READ_FROM_PAR_FILE
   eng "Failed to read from the .par file"
   swe "Misslyckades läsa från .par filen"
+ER_PLUGIN_IS_PERMANENT
+  eng "Plugin '%s' is force_plus_permanent and can not be unloaded"
diff --git a/sql/sql_plugin.cc b/sql/sql_plugin.cc
index 956be657af2..71e2f844168 100644
--- a/sql/sql_plugin.cc
+++ b/sql/sql_plugin.cc
@@ -41,9 +41,8 @@ extern struct st_mysql_plugin *mysql_mandatory_plugins[];
   @note The order of the enumeration is critical.
   @see construct_options
 */
-static const char *global_plugin_typelib_names[]=
-  { "OFF", "ON", "FORCE", NULL };
-enum enum_plugin_load_policy {PLUGIN_OFF, PLUGIN_ON, PLUGIN_FORCE};
+const char *global_plugin_typelib_names[]=
+  { "OFF", "ON", "FORCE", "FORCE_PLUS_PERMANENT", NULL };
 static TYPELIB global_plugin_typelib=
   { array_elements(global_plugin_typelib_names)-1,
     "", global_plugin_typelib_names, NULL };
@@ -796,6 +795,7 @@ static bool plugin_add(MEM_ROOT *tmp_root,
       tmp.name.length= name_len;
       tmp.ref_count= 0;
       tmp.state= PLUGIN_IS_UNINITIALIZED;
+      tmp.load_option= PLUGIN_ON;
       if (test_plugin_options(tmp_root, &tmp, argc, argv))
         tmp.state= PLUGIN_IS_DISABLED;
 
@@ -1237,7 +1237,7 @@ int plugin_init(int *argc, char **argv, int flags)
       tmp.name.str= (char *)plugin->name;
       tmp.name.length= strlen(plugin->name);
       tmp.state= 0;
-      tmp.is_mandatory= mandatory;
+      tmp.load_option= mandatory ? PLUGIN_FORCE : PLUGIN_ON;
 
       /*
         If the performance schema is compiled in,
@@ -1256,7 +1256,7 @@ int plugin_init(int *argc, char **argv, int flags)
           to work, by using '--skip-performance-schema' (the plugin)
       */
       if (!my_strcasecmp(&my_charset_latin1, plugin->name, "PERFORMANCE_SCHEMA"))
-        tmp.is_mandatory= true;
+        tmp.load_option= PLUGIN_FORCE;
 
       free_root(&tmp_root, MYF(MY_MARK_BLOCKS_FREE));
       if (test_plugin_options(&tmp_root, &tmp, argc, argv))
@@ -1334,7 +1334,8 @@ int plugin_init(int *argc, char **argv, int flags)
   while ((plugin_ptr= *(--reap)))
   {
     mysql_mutex_unlock(&LOCK_plugin);
-    if (plugin_ptr->is_mandatory)
+    if (plugin_ptr->load_option == PLUGIN_FORCE ||
+        plugin_ptr->load_option == PLUGIN_FORCE_PLUS_PERMANENT)
       reaped_mandatory_plugin= TRUE;
     plugin_deinitialize(plugin_ptr, true);
     mysql_mutex_lock(&LOCK_plugin);
@@ -1844,6 +1845,11 @@ bool mysql_uninstall_plugin(THD *thd, const LEX_STRING *name)
     my_error(ER_SP_DOES_NOT_EXIST, MYF(0), "PLUGIN", name->str);
     goto err;
   }
+  if (plugin->load_option == PLUGIN_FORCE_PLUS_PERMANENT)
+  {
+    my_error(ER_PLUGIN_IS_PERMANENT, MYF(0), name->str);
+    goto err;
+  }
 
   plugin->state= PLUGIN_IS_DELETED;
   if (plugin->ref_count)
@@ -3054,7 +3060,8 @@ static int construct_options(MEM_ROOT *mem_root, struct st_plugin_int *tmp,
                                                   plugin_dash.length + 1);
   strxmov(plugin_name_with_prefix_ptr, plugin_dash.str, plugin_name_ptr, NullS);
 
-  if (!tmp->is_mandatory)
+  if (tmp->load_option != PLUGIN_FORCE &&
+      tmp->load_option != PLUGIN_FORCE_PLUS_PERMANENT)
   {
     /* support --skip-plugin-foo syntax */
     options[0].name= plugin_name_ptr;
@@ -3314,7 +3321,7 @@ static int test_plugin_options(MEM_ROOT *tmp_root, struct st_plugin_int *tmp,
 {
   struct sys_var_chain chain= { NULL, NULL };
   bool disable_plugin;
-  enum_plugin_load_policy plugin_load_policy= tmp->is_mandatory ? PLUGIN_FORCE : PLUGIN_ON;
+  enum_plugin_load_option plugin_load_option= tmp->load_option;
 
   MEM_ROOT *mem_root= alloc_root_inited(&tmp->mem_root) ?
                       &tmp->mem_root : &plugin_mem_root;
@@ -3335,7 +3342,7 @@ static int test_plugin_options(MEM_ROOT *tmp_root, struct st_plugin_int *tmp,
   */
   if (!(my_strcasecmp(&my_charset_latin1, tmp->name.str, "federated") &&
       my_strcasecmp(&my_charset_latin1, tmp->name.str, "ndbcluster")))
-    plugin_load_policy= PLUGIN_OFF;
+    plugin_load_option= PLUGIN_OFF;
 
   for (opt= tmp->plugin->system_vars; opt && *opt; opt++)
     count+= 2; /* --{plugin}-{optname} and --plugin-{plugin}-{optname} */
@@ -3359,8 +3366,9 @@ static int test_plugin_options(MEM_ROOT *tmp_root, struct st_plugin_int *tmp,
       We adjust the default value to account for the hardcoded exceptions
       we have set for the federated and ndbcluster storage engines.
     */
-    if (!tmp->is_mandatory)
-      opts[0].def_value= opts[1].def_value= plugin_load_policy;
+    if (tmp->load_option != PLUGIN_FORCE &&
+        tmp->load_option != PLUGIN_FORCE_PLUS_PERMANENT)
+      opts[0].def_value= opts[1].def_value= plugin_load_option;
 
     error= handle_options(argc, &argv, opts, NULL);
     (*argc)++; /* add back one for the program name */
@@ -3375,12 +3383,13 @@ static int test_plugin_options(MEM_ROOT *tmp_root, struct st_plugin_int *tmp,
      Set plugin loading policy from option value. First element in the option
      list is always the <plugin name> option value.
     */
-    if (!tmp->is_mandatory)
-      plugin_load_policy= (enum_plugin_load_policy)*(ulong*)opts[0].value;
+    if (tmp->load_option != PLUGIN_FORCE &&
+        tmp->load_option != PLUGIN_FORCE_PLUS_PERMANENT)
+      plugin_load_option= (enum_plugin_load_option) *(ulong*) opts[0].value;
   }
 
-  disable_plugin= (plugin_load_policy == PLUGIN_OFF);
-  tmp->is_mandatory= (plugin_load_policy == PLUGIN_FORCE);
+  disable_plugin= (plugin_load_option == PLUGIN_OFF);
+  tmp->load_option= plugin_load_option;
 
   /*
     If the plugin is disabled it should not be initialized.
diff --git a/sql/sql_plugin.h b/sql/sql_plugin.h
index 079dc4e6dca..5fa9afb3066 100644
--- a/sql/sql_plugin.h
+++ b/sql/sql_plugin.h
@@ -32,6 +32,9 @@
 
 class sys_var;
 enum SHOW_COMP_OPTION { SHOW_OPTION_YES, SHOW_OPTION_NO, SHOW_OPTION_DISABLED};
+enum enum_plugin_load_option { PLUGIN_OFF, PLUGIN_ON, PLUGIN_FORCE,
+  PLUGIN_FORCE_PLUS_PERMANENT };
+extern const char *global_plugin_typelib_names[];
 
 #include <my_sys.h>
 
@@ -95,7 +98,7 @@ struct st_plugin_int
   void *data;                   /* plugin type specific, e.g. handlerton */
   MEM_ROOT mem_root;            /* memory for dynamic plugin structures */
   sys_var *system_vars;         /* server variables for this plugin */
-  bool is_mandatory;            /* If true then plugin must not fail to load */
+  enum enum_plugin_load_option load_option; /* OFF, ON, FORCE, F+PERMANENT */
 };
 
 
@@ -110,6 +113,7 @@ typedef struct st_plugin_int *plugin_ref;
 #define plugin_data(pi,cast) ((cast)((pi)->data))
 #define plugin_name(pi) (&((pi)->name))
 #define plugin_state(pi) ((pi)->state)
+#define plugin_load_option(pi) ((pi)->load_option)
 #define plugin_equals(p1,p2) ((p1) == (p2))
 #else
 typedef struct st_plugin_int **plugin_ref;
@@ -118,6 +122,7 @@ typedef struct st_plugin_int **plugin_ref;
 #define plugin_data(pi,cast) ((cast)((pi)[0]->data))
 #define plugin_name(pi) (&((pi)[0]->name))
 #define plugin_state(pi) ((pi)[0]->state)
+#define plugin_load_option(pi) ((pi)[0]->load_option)
 #define plugin_equals(p1,p2) ((p1) && (p2) && (p1)[0] == (p2)[0])
 #endif