Bug #26173244: THE UDF INSTALL SERVICE CAN'T BE USED AT

 PLUGIN INSTALLS

Split the UDF initialization/deinitialization into two:
1. Initialization/deinitialization of the global structures
2. Loading of the UDF definitions from the table and removing them from the global

Then kept the #2 at the place of the current initialization/deinitalization
routines and added #2 initialization very early (before component/plugin
initialization) and #2 deinitialization very late (after the plugin/compononent
deinitialization.

Added a test plugin and a regression test.

mysql-test/include/plugin.defs

@@ -55,6 +55,7 @@ rewrite_example    			plugin_output_directory REWRITE_EXAMPLE
 rewriter           			plugin_output_directory REWRITER
 mysql_no_login     			plugin_output_directory MYSQL_NO_LOGIN    mysql_no_login
 test_udf_services  			plugin_output_directory TESTUDFSERVICES
+test_udf_services  			plugin_output_directory TESTUDFREGISTRATION test_udf_registration
 group_replication  			plugin_output_directory GROUP_REPLICATION
 locking_service    			plugin_output_directory LOCKING_SERVICE
 version_token      			plugin_output_directory VERSION_TOKEN

mysql-test/suite/test_services/r/test_udf_registration.result

@@ -0,0 +1,18 @@
+INSTALL PLUGIN test_udf_registration SONAME 'test_udf_services.so';
+# Must work
+SELECT test_udf_registration_udf();
+test_udf_registration_udf()
+0
+UNINSTALL PLUGIN test_udf_registration;
+# Must fail: no UDF
+SELECT test_udf_registration_udf();
+ERROR 42000: FUNCTION test.test_udf_registration_udf does not exist
+INSTALL PLUGIN test_udf_registration SONAME 'test_udf_services.so';
+# Restart the server
+# restart
+# Must work after a restart
+SELECT test_udf_registration_udf();
+test_udf_registration_udf()
+0
+# Cleanup
+UNINSTALL PLUGIN test_udf_registration;

mysql-test/suite/test_services/t/test_udf_registration-master.opt

@@ -0,0 +1,2 @@
+$TESTUDFREGISTRATION_OPT
+--local-infile=true

mysql-test/suite/test_services/t/test_udf_registration.test

@@ -0,0 +1,28 @@
+# Save the initial number of concurrent sessions
+--source include/count_sessions.inc
+
+--replace_regex /\.dll/.so/
+eval INSTALL PLUGIN test_udf_registration SONAME '$TESTUDFREGISTRATION';
+
+--echo # Must work
+SELECT test_udf_registration_udf();
+
+UNINSTALL PLUGIN test_udf_registration;
+
+--echo # Must fail: no UDF
+--error ER_SP_DOES_NOT_EXIST
+SELECT test_udf_registration_udf();
+
+--replace_regex /\.dll/.so/
+eval INSTALL PLUGIN test_udf_registration SONAME '$TESTUDFREGISTRATION';
+
+
+--echo # Restart the server
+--source include/restart_mysqld.inc
+
+
+--echo # Must work after a restart
+SELECT test_udf_registration_udf();
+
+--echo # Cleanup
+UNINSTALL PLUGIN test_udf_registration;

plugin/udf_services/test_udf_services.cc

@@ -21,6 +21,9 @@
 #include "my_compiler.h"
 #include "my_inttypes.h"
 
+static int test_udf_registration_init(MYSQL_PLUGIN p);
+static int test_udf_registration_deinit(MYSQL_PLUGIN p);
+
 /**
   @file test_udf_services.cc
 
@@ -36,6 +39,9 @@
 static struct st_mysql_daemon test_udf_services_plugin=
 { MYSQL_DAEMON_INTERFACE_VERSION  };
 
+static struct st_mysql_daemon test_udf_registration_plugin=
+{ MYSQL_DAEMON_INTERFACE_VERSION };
+
 mysql_declare_plugin(test_udf_services)
 {
   MYSQL_DAEMON_PLUGIN,
@@ -52,6 +58,22 @@ mysql_declare_plugin(test_udf_services)
   NULL,                       /* system variables     */
   NULL,                       /* config options       */
   0,                          /* flags                */
+},
+{
+  MYSQL_DAEMON_PLUGIN,
+  &test_udf_registration_plugin,
+  "test_udf_registration",
+  "Georgi Kodinov",
+  "MySQL mtr test framework",
+  PLUGIN_LICENSE_GPL,
+  test_udf_registration_init, /* Plugin Init          */
+  NULL,                       /* Plugin Check uninstall */
+  test_udf_registration_deinit, /* Plugin Deinit        */
+  0x0100,                     /* Plugin version: 1.0  */
+  NULL,                       /* status variables     */
+  NULL,                       /* system variables     */
+  NULL,                       /* config options       */
+  0,                          /* flags                */
 }
 mysql_declare_plugin_end;
 
@@ -78,7 +100,7 @@ test_udf_services_udf_init(UDF_INIT *initid MY_ATTRIBUTE((unused)),
                            UDF_ARGS *args MY_ATTRIBUTE((unused)),
                            char *message MY_ATTRIBUTE((unused)))
 {
-  return FALSE;
+  return false;
 }
 
 
@@ -103,3 +125,72 @@ test_udf_services_udf(UDF_INIT *initid MY_ATTRIBUTE((unused)),
   my_snprintf(buffer, sizeof(buffer), "test");
   return 0;
 }
+
+#include <mysql/service_plugin_registry.h>
+#include <mysql/components/my_service.h>
+#include <mysql/components/services/udf_registration.h>
+
+/** Sample plugin init function that registers a UDF */
+static int test_udf_registration_init(MYSQL_PLUGIN /*p */)
+{
+  SERVICE_TYPE(registry) *reg;
+  SERVICE_TYPE(udf_registration) *udf;
+  bool ret= false;
+
+  reg= mysql_plugin_registry_acquire();
+  if (!reg)
+  {
+    ret= true;
+    goto end;
+  }
+  reg->acquire("udf_registration", (my_h_service *) &udf);
+  if (!udf)
+  {
+    ret= true;
+    goto end;
+  }
+  ret= udf->udf_register("test_udf_registration_udf", INT_RESULT,
+                         (Udf_func_any) test_udf_services_udf,
+                         test_udf_services_udf_init,
+                         NULL);
+
+  reg->release((my_h_service) udf);
+end:
+  if (reg)
+    mysql_plugin_registry_release(reg);
+  return ret ? 1 : 0;
+}
+
+
+/** Sample plugin init function that unregisters a UDF */
+static int test_udf_registration_deinit(MYSQL_PLUGIN /* p */)
+{
+  SERVICE_TYPE(registry) *reg;
+  SERVICE_TYPE(udf_registration) *udf;
+  bool ret= false;
+  int was_present;
+
+  reg= mysql_plugin_registry_acquire();
+  if (!reg)
+  {
+    ret= true;
+    goto end;
+  }
+  reg->acquire("udf_registration", (my_h_service *) &udf);
+  if (!udf)
+  {
+    ret= true;
+    goto end;
+  }
+
+  ret= udf->udf_unregister("test_udf_registration_udf", &was_present);
+
+end:
+  if (reg)
+  {
+    if (udf)
+      reg->release((my_h_service) udf);
+    mysql_plugin_registry_release(reg);
+  }
+  return ret ? 1 : 0;
+}

sql/mysqld.cc

@@ -1973,7 +1973,7 @@ static void clean_up(bool print_message)
   lex_free();       /* Free some memory */
   item_create_cleanup();
   if (!opt_noacl)
-    udf_deinit();
+    udf_unload_udfs();
   table_def_start_shutdown();
   plugin_shutdown();
   gtid_server_cleanup(); // after plugin_shutdown
@@ -2065,6 +2065,7 @@ static void clean_up(bool print_message)
 
   persisted_variables_cache.cleanup();
 
+  udf_deinit_globals();
   /*
     The following lines may never be executed as the main thread may have
     killed us
@@ -4587,6 +4588,13 @@ static int init_server_components()
     unireg_abort(MYSQLD_ABORT_EXIT);
   }
 
+  /*
+    We need to initialize the UDF globals early before reading the proc table
+    and before the server component initialization to allow other components
+    to register their UDFs at init time and de-register them at deinit time.
+  */
+  udf_init_globals();
+
   /*
     Set tc_log to point to TC_LOG_DUMMY early in order to allow plugin_init()
     to commit attachable transaction after reading from mysql.plugin table.
@@ -5796,7 +5804,7 @@ int mysqld_main(int argc, char **argv)
 
   if (!opt_noacl)
   {
-    udf_init();
+    udf_read_functions_table();
   }
 
   init_status_vars();

sql/sql_udf.cc

@@ -173,42 +173,62 @@ static void init_udf_psi_keys(void)
 }
 #endif
 
+/**
+  Initialize the UDF global structures.
+  This is done as a separate step so that the UDF registration
+  service can work when initalizing plugins, which happens
+  before reading the UDF table.
+*/
+void udf_init_globals()
+{
+  DBUG_ENTER("udf_init_globals");
+  if (initialized)
+    DBUG_VOID_RETURN;
+
+#ifdef HAVE_PSI_INTERFACE
+  init_udf_psi_keys();
+#endif
+
+  mysql_rwlock_init(key_rwlock_THR_LOCK_udf, &THR_LOCK_udf);
+  init_sql_alloc(key_memory_udf_mem, &mem, UDF_ALLOC_BLOCK_SIZE, 0);
+
+  udf_hash= new collation_unordered_map<std::string, udf_func *>(
+    system_charset_info, key_memory_udf_mem);
+  initialized= 1;
+
+  DBUG_VOID_RETURN;
+}
+
+
 /*
   Read all predeclared functions from mysql.func and accept all that
   can be used.
+  The global structures must be initialized first.
 */
-
-void udf_init()
+void udf_read_functions_table()
 {
   udf_func *tmp;
   TABLE_LIST tables;
   READ_RECORD read_record_info;
   TABLE *table;
   int error;
-  DBUG_ENTER("ufd_init");
+  DBUG_ENTER("ufd_read_functions_table");
   char db[]= "mysql"; /* A subject to casednstr, can't be constant */
 
-  if (initialized)
+  if (!initialized)
+  {
+    DBUG_ASSERT("wrong init order: trying to read the UDFs without initializaton");
     DBUG_VOID_RETURN;
-
-#ifdef HAVE_PSI_INTERFACE
-  init_udf_psi_keys();
-#endif
-
-  mysql_rwlock_init(key_rwlock_THR_LOCK_udf, &THR_LOCK_udf);
-  init_sql_alloc(key_memory_udf_mem, &mem, UDF_ALLOC_BLOCK_SIZE, 0);
+  }
 
   THD *new_thd = new(std::nothrow) THD;
   if (new_thd == nullptr)
   {
     LogErr(ERROR_LEVEL, ER_UDF_CANT_ALLOC_FOR_STRUCTURES);
-    free_root(&mem,MYF(0));
+    free_root(&mem, MYF(0));
     delete new_thd;
     DBUG_VOID_RETURN;
   }
-  udf_hash= new collation_unordered_map<std::string, udf_func*>(
-    system_charset_info, key_memory_udf_mem);
-  initialized = 1;
   new_thd->thread_stack= (char*) &new_thd;
   new_thd->store_globals();
   {
@@ -312,16 +332,11 @@ void udf_init()
 /**
    Deintialize the UDF subsystem.
 
-   This function does the following:
-   1. Closes the shared libaries.
-   2. Free the UDF hash.
-   3. Free the memroot allocated.
-   4. Destroy the RW mutex object.
+   This function closes the shared libaries.
 */
-void udf_deinit()
+void udf_unload_udfs()
 {
-  /* close all shared libraries */
-  DBUG_ENTER("udf_free");
+  DBUG_ENTER("udf_unload_udfs");
   if (udf_hash != nullptr)
   {
     for (auto it1= udf_hash->begin(); it1 != udf_hash->end(); ++it1)
@@ -339,6 +354,24 @@ void udf_deinit()
         dlclose(udf->dlhandle);
       }
     }
+  }
+  DBUG_VOID_RETURN;
+}
+
+
+/**
+   Deintialize the UDF subsystem.
+
+   This function does the following:
+   1. Free the UDF hash.
+   2. Free the memroot allocated.
+   3. Destroy the RW mutex object.
+*/
+void udf_deinit_globals()
+{
+  DBUG_ENTER("udf_deinit_globals");
+  if (udf_hash != nullptr)
+  {
     delete udf_hash;
     udf_hash= nullptr;
   }

sql/sql_udf.h

@@ -136,7 +136,10 @@ class udf_handler :public Sql_alloc
 };
 
 
-void udf_init(void),udf_deinit(void);
+void udf_init_globals();
+void udf_read_functions_table();
+void udf_unload_udfs();
+void udf_deinit_globals();
 udf_func *find_udf(const char *name, size_t len=0,bool mark_used=0);
 void free_udf(udf_func *udf);
 bool mysql_create_function(THD *thd, udf_func *udf);