Fix for bug#18177 any access to INFORMATION_SCHEMA.ROUTINES crashes

replaced get_field(MEM_ROOT *mem, Field *field) with 
get_field(MEM_ROOT *mem, Field *field, String *res).
It allows to avoid strlen().

mysql-test/r/information_schema.result

@@ -1099,3 +1099,12 @@ CHARACTER_MAXIMUM_LENGTH	CHARACTER_OCTET_LENGTH
 1	3
 9	27
 drop table t1;
+use mysql;
+INSERT INTO `proc` VALUES ('test','','PROCEDURE','','SQL','CONTAINS_SQL',
+'NO','DEFINER','','','BEGIN\r\n  \r\nEND','root@%','2006-03-02 18:40:03',
+'2006-03-02 18:40:03','','');
+select routine_name from information_schema.routines;
+routine_name
+
+delete from proc where name='';
+use test;

mysql-test/t/information_schema.test

@@ -811,3 +811,14 @@ default character set utf8;
 select CHARACTER_MAXIMUM_LENGTH, CHARACTER_OCTET_LENGTH from
 information_schema.columns where table_schema='test' and table_name = 't1';
 drop table t1;
+
+#
+# Bug#18177 any access to INFORMATION_SCHEMA.ROUTINES crashes
+#
+use mysql;
+INSERT INTO `proc` VALUES ('test','','PROCEDURE','','SQL','CONTAINS_SQL',
+'NO','DEFINER','','','BEGIN\r\n  \r\nEND','root@%','2006-03-02 18:40:03',
+'2006-03-02 18:40:03','','');
+select routine_name from information_schema.routines;
+delete from proc where name='';
+use test;

sql/sql_show.cc

@@ -2854,17 +2854,18 @@ bool store_schema_proc(THD *thd, TABLE *table, TABLE *proc_table,
                        const char *wild, bool full_access, const char *sp_user)
 {
   String tmp_string;
+  String sp_db, sp_name, definer;
   TIME time;
   LEX *lex= thd->lex;
   CHARSET_INFO *cs= system_charset_info;
-  const char *sp_db, *sp_name, *definer;
-  sp_db= get_field(thd->mem_root, proc_table->field[0]);
-  sp_name= get_field(thd->mem_root, proc_table->field[1]);
-  definer= get_field(thd->mem_root, proc_table->field[11]);
+  get_field(thd->mem_root, proc_table->field[0], &sp_db);
+  get_field(thd->mem_root, proc_table->field[1], &sp_name);
+  get_field(thd->mem_root, proc_table->field[11], &definer);
   if (!full_access)
-    full_access= !strcmp(sp_user, definer);
-  if (!full_access && check_some_routine_access(thd, sp_db, sp_name,
-			proc_table->field[2]->val_int() == TYPE_ENUM_PROCEDURE))
+    full_access= !strcmp(sp_user, definer.ptr());
+  if (!full_access && check_some_routine_access(thd, sp_db.ptr(), sp_name.ptr(),
+                                                proc_table->field[2]->val_int() ==
+                                                TYPE_ENUM_PROCEDURE))
     return 0;
 
   if (lex->orig_sql_command == SQLCOM_SHOW_STATUS_PROC &&
@@ -2874,13 +2875,13 @@ bool store_schema_proc(THD *thd, TABLE *table, TABLE *proc_table,
       lex->orig_sql_command == SQLCOM_END)
   {
     restore_record(table, s->default_values);
-    if (!wild || !wild[0] || !wild_compare(sp_name, wild, 0))
+    if (!wild || !wild[0] || !wild_compare(sp_name.ptr(), wild, 0))
     {
       int enum_idx= proc_table->field[5]->val_int();
-      table->field[3]->store(sp_name, strlen(sp_name), cs);
+      table->field[3]->store(sp_name.ptr(), sp_name.length(), cs);
       get_field(thd->mem_root, proc_table->field[3], &tmp_string);
       table->field[0]->store(tmp_string.ptr(), tmp_string.length(), cs);
-      table->field[2]->store(sp_db, strlen(sp_db), cs);
+      table->field[2]->store(sp_db.ptr(), sp_db.length(), cs);
       get_field(thd->mem_root, proc_table->field[2], &tmp_string);
       table->field[4]->store(tmp_string.ptr(), tmp_string.length(), cs);
       if (proc_table->field[2]->val_int() == TYPE_ENUM_FUNCTION)
@@ -2912,7 +2913,7 @@ bool store_schema_proc(THD *thd, TABLE *table, TABLE *proc_table,
       table->field[17]->store(tmp_string.ptr(), tmp_string.length(), cs);
       get_field(thd->mem_root, proc_table->field[15], &tmp_string);
       table->field[18]->store(tmp_string.ptr(), tmp_string.length(), cs);
-      table->field[19]->store(definer, strlen(definer), cs);
+      table->field[19]->store(definer.ptr(), definer.length(), cs);
       return schema_table_store_record(thd, table);
     }
   }