Bug #99496 m_admin_interface_listen_socket and port not correspond in m_socket_map

Description:
Can not connect to mysqld through socket when write admin port Small probability.
server hangs.

How to repeat:
write '
admin_address = 127.0.0.1
admin_port = 33062
'
into my.cnf

startup mysqld 

/*connect mysqld through mysql.sock(non admin port)*/
mysql -uroot --skip-password --socket=mysql.sock

Suggested fix:
in Mysqld_socket_listener::setup_listener(), the m_admin_interface_listen_socket will insert into m_socket_map as m_socket_map[0],but m_socket_map will sort as socket fd Ascending order when new socket insert.

if the admin_socket fd is 78, port is 33062, later, the non_admin_sock fd is 76,port is 3306, insert into the map, now, the map will be 
<76, 3306>
<78, 33062>

in  Mysqld_socket_listener::get_ready_socket, when we connect through socket, the fd 76 will get a revents, the fd 76 is the frist member in map, in code, return  m_admin_interface_listen_socket, so, listen and handle a wrong socket.

as how to fix i think can get a non-order map to save m_socket_map .

Hi Mr. pang,

Thank you for your bug report.

However, I am not able to repeat your bug with 8.0.20.

This is the excerpt from my.cnf:

---------------
admin_address = 127.0.0.1
admin_port = 33062
_______________

I had no problem of connecting through the socket with ordinary user:

-------------------

mysql -uXXXXXX -pXXXXXX --socket=/private/tmp/mysql.sock test
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 8.0.20-debug Source distribution

Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

------------------

And I had no problem of executing any command in mysql.CLI:

------------------
mysql> use information_schema;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> show tables;
+---------------------------------------+
| Tables_in_information_schema          |
+---------------------------------------+
| ADMINISTRABLE_ROLE_AUTHORIZATIONS     |
| APPLICABLE_ROLES                      |
| CHARACTER_SETS                        |
| CHECK_CONSTRAINTS                     |
| COLLATION_CHARACTER_SET_APPLICABILITY |
| COLLATIONS                            |
| COLUMN_PRIVILEGES                     |
| COLUMN_STATISTICS                     |
| COLUMNS                               |
| ENABLED_ROLES                         |
| ENGINES                               |
| EVENTS                                |
| FILES                                 |
| INNODB_BUFFER_PAGE                    |
| INNODB_BUFFER_PAGE_LRU                |
| INNODB_BUFFER_POOL_STATS              |
| INNODB_CACHED_INDEXES                 |
| INNODB_CMP                            |
| INNODB_CMP_PER_INDEX                  |
| INNODB_CMP_PER_INDEX_RESET            |
| INNODB_CMP_RESET                      |
| INNODB_CMPMEM                         |
| INNODB_CMPMEM_RESET                   |
| INNODB_COLUMNS                        |
| INNODB_DATAFILES                      |
| INNODB_FIELDS                         |
| INNODB_FOREIGN                        |
| INNODB_FOREIGN_COLS                   |
| INNODB_FT_BEING_DELETED               |
| INNODB_FT_CONFIG                      |
| INNODB_FT_DEFAULT_STOPWORD            |
| INNODB_FT_DELETED                     |
| INNODB_FT_INDEX_CACHE                 |
| INNODB_FT_INDEX_TABLE                 |
| INNODB_INDEXES                        |
| INNODB_METRICS                        |
| INNODB_SESSION_TEMP_TABLESPACES       |
| INNODB_TABLES                         |
| INNODB_TABLESPACES                    |
| INNODB_TABLESPACES_BRIEF              |
| INNODB_TABLESTATS                     |
| INNODB_TEMP_TABLE_INFO                |
| INNODB_TRX                            |
| INNODB_VIRTUAL                        |
| KEY_COLUMN_USAGE                      |
| KEYWORDS                              |
| OPTIMIZER_TRACE                       |
| PARAMETERS                            |
| PARTITIONS                            |
| PLUGINS                               |
| PROCESSLIST                           |
| PROFILING                             |
| REFERENTIAL_CONSTRAINTS               |
| RESOURCE_GROUPS                       |
| ROLE_COLUMN_GRANTS                    |
| ROLE_ROUTINE_GRANTS                   |
| ROLE_TABLE_GRANTS                     |
| ROUTINES                              |
| SCHEMA_PRIVILEGES                     |
| SCHEMATA                              |
| ST_GEOMETRY_COLUMNS                   |
| ST_SPATIAL_REFERENCE_SYSTEMS          |
| ST_UNITS_OF_MEASURE                   |
| STATISTICS                            |
| TABLE_CONSTRAINTS                     |
| TABLE_PRIVILEGES                      |
| TABLES                                |
| TABLESPACES                           |
| TRIGGERS                              |
| USER_PRIVILEGES                       |
| VIEW_ROUTINE_USAGE                    |
| VIEW_TABLE_USAGE                      |
| VIEWS                                 |
+---------------------------------------+
73 rows in set (0.01 sec)
__________________

And I had no problem in shutting down MySQL server 8.0.20.

Hence, I do not see how can this be a bug .......

hi, mr Milivojevic,
Thank for your reply.
I also hardlly Reproduce the problem local.
I have some result screenshot show you, in files.

admin socket bind error

Attachment: 未命名图片.png (image/png, text), 64.90 KiB.

admin fd bind the second m_fds

Attachment: CEBF9C82-71BF-4E89-9A2C-5BE96EA47E5F.png (image/png, text), 8.89 KiB.

admin fd first insert, non admin fd is less than admin fd, so the non admin fd be the first one

Attachment: 未命名图片1.png (image/png, text), 73.31 KiB.

Hi Mr. pang,

Thank you for your feedback. However, what we require is a fully reproducible test case, not pictures.

Next, if you are connecting through the socket file, you can do it only locally.

Last, but not least, I tried connecting remotely, through the non-admin port and I did not have any problems.