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Georg Richter edited this page Jan 31, 2024 · 24 revisions

Name

mysql_optionsv - Used to set extra connect options and affect behavior of a connection

Synopsis

#include <mysql.h>

int mysql_optionsv(MYSQL * mysql,
                   enum mysql_option,
                   const void * arg,
                   ...);

Description

Used to set extra connect options and affect behavior for a connection. This function may be called multiple times to set several options. mysql_optionsv() should be called after mysql_init().

Options

The following table shows which variable type to use for each option.

Variable Type Values
my_bool MYSQL_OPT_RECONNECT, MYSQL_SECURE_AUTH, MYSQL_REPORT_DATA_TRUNCATION, MYSQL_OPT_SSL_ENFORCE, MYSQL_OPT_SSL_VERIFY_SERVER_CERT, MARIADB_OPT_SKIP_READ_RESPONSE
unsigned int MYSQL_OPT_PORT, MYSQL_OPT_LOCAL_INFILE, MYSQL_OPT_CONNECT_TIMEOUT, MYSQL_OPT_PROTOCOL, MYSQL_OPT_READ_TIMEOUT, MYSQL_OPT_WRITE_TIMEOUT
unsigned long MYSQL_OPT_NET_BUFFER_LENGTH, MYSQL_OPT_MAX_ALLOWED_PACKET
const char * MYSQL_INIT_COMMAND, MARIADB_OPT_UNIXSOCKET, MARIADB_OPT_PASSWORD , MARIADB_OPT_USER, MARIADB_OPT_HOST, MARIADB_OPT_SCHEMA, MYSQL_OPT_SSL_KEY, MYSQL_OPT_SSL_CERT, MYSQL_OPT_SSL_CA, MYSQL_OPT_SSL_CAPATH, MYSQL_SET_CHARSET_NAME, MYSQL_SET_CHARSET_DIR, MYSQL_OPT_SSL_CIPHER, MYSQL_SHARED_MEMORY_BASE_NAME, MYSQL_PLUGIN_DIR, MYSQL_DEFAULT_AUTH, MARIADB_OPT_SSL_FP, MARIADB_OPT_SSL_FP_LIST, MARIADB_OPT_TLS_PASSPHRASE, MARIADB_OPT_TLS_VERSION, MYSQL_OPT_BIND, MYSQL_OPT_CONNECT_ATTR_DELETE, MYSQL_OPT_CONNECT_ATTR_ADD, MARIADB_OPT_CONNECTION_HANDLER, MYSQL_SERVER_PUBLIC_KEY, MARIADB_OPT_RESTRICTED_AUTH
const char*, unsigned int MARIADB_OPT_RPL_REGISTER_REPLICA
- MYSQL_OPT_CONNECT_ATTR_RESET
void * MARIADB_OPT_PROXY_HEADER
  • MYSQL_INIT_COMMAND
    Command(s) which will be executed when connecting and reconnecting to the server.
  • MYSQL_OPT_COMPRESS
    Use the compressed protocol for client server communication. If the server doesn't support compressed protocol, the default protocol will be used.
  • MYSQL_OPT_CONNECT_TIMEOUT
    Connect timeout in seconds. This value will be passed as an unsigned ##int## parameter.
  • MYSQL_OPT_LOCAL_INFILE
    Enable or disable the use of LOAD DATA LOCAL INFILE
  • MYSQL_OPT_NAMED_PIPE
    For Windows operating systems only: Use named pipes for client/server communication.
  • MYSQL_PROGRESS_CALLBACK
    Specifies a callback function which will be able to visualize the progress of certain long running statements (i.e. LOAD DATA LOCAL INFILE or ALTER TABLE). The callback function must be defined as followed:
static void report_progress(const MYSQL *mysql __attribute__((unused)),
                            uint stage, uint max_stage,
                            double progress __attribute__((unused)),
                            const char *proc_info __attribute__((unused)),
                            uint proc_info_length __attribute__((unused)))
  • MYSQL_OPT_PROTOCOL
    Specify the type of client/server protocol. Possible values are: MYSQL_PROTOCOL_TCP, MYSQL_PROTOCOL_SOCKET, MYSQL_PROTOCOL_PIPE and MYSQL_PROTOCOL_MEMORY.
  • MYSQL_OPT_RECONNECT
    Enable or disable automatic reconnect.
  • MYSQL_OPT_READ_TIMEOUT
    Specifies the timeout in seconds for reading packets from the server.
  • MYSQL_OPT_WRITE_TIMEOUT
    Specifies the timeout in seconds for sending packets to the server.
  • MYSQL_READ_DEFAULT_FILE
    Read options from named configuration file. To read from default my.cnf configuration file, a NULL pointer has to be passed with option MYSQL_READ_DEFAULT_GROUP. Note: MariaDB Connector/C will not read the configuration by default. If MYSQL_READ_DEFAULT_FILE is specified the following sections will be always processed:
    • [client]
    • [client-server]
    • [client-mariadb]
  • MYSQL_READ_DEFAULT_GROUP
    Read options from the named group from default configuration file or the file specified with MYSQL_READ_DEFAULT_FILE.
  • MYSQL_REPORT_DATA_TRUNCATION
    Enable or disable reporting data truncation errors for prepared statements.
  • MYSQL_OPT_BIND
    Specify the network interface from which to connect to MariaDB Server.
  • MYSQL_PLUGIN_DIR
    Specify the location of client plugins.
  • MYSQL_OPT_NONBLOCK
    Specify stack size for non blocking operations. The argument for MYSQL_OPT_NONBLOCK is the size of the stack used to save the state of a non-blocking operation while it is waiting for I/O and the application is doing other processing. Normally, applications will not have to change this, and it can be passed as zero to use the default value.
  • MYSQL_OPT_NET_BUFFER_LENGTH
    Initial network buffer size in bytes. The default value is 16777216 (16MiB).
  • MYSQL_OPT_MAX_ALLOWED_PACKET
    Maximum allowed packet length. The default value is 1073741824 (1GiB) on the client side. If the limit is exceeded by a packet sent by the server, an error is generated.
  • MARIADB_OPT_CONNECTION_HANDLER
    Specify the name of a connection handler plugin.
  • MARIADB_OPT_USERDATA
    Bundle user data to the current connection, e.g. for use in connection handler plugins. This option requires 4 parameters: connection, option, key and value:
mysql_optionsv(mysql, MARIADB_OPT_USERDATA, (void *)"ssh_user", (void *)ssh_user);
  • MARIADB_OPT_CONNECTION_READ_ONLY
    This option is used by connection handler plugins and indicates that the current connection will be used for read operations only.
  • MYSQL_OPT_CAN_HANDLE_EXPIRED_PASSWORDS
    If this option is set, the client indicates that it will be able to handle expired passwords by setting the CLIENT_CAN_HANDLE_EXPIRED_PASSWORDS capability flag. If the password has expired and CLIENT_CAN_HANDLE_EXPIRED_PASSWORDS is set, the server will not return an error when connecting, but put the connection in sandbox mode, where all commands will return error 1820 (ER_MUST_CHANGE_PASSWORD) unless a new password was set. This option was added in MariaDB Connector/C 3.0.4
  • MARIADB_OPT_STATUS_CALLBACK
    Specifies a callback function which will be called whenever the server status changes or the server sent session_track information to the client:
mysql_optionsv(mysql, MARIADB_OPT_STATUS_CALLBACK, function, data)

The callback function must be defined as follows:

    void status_callback(void *data, enum enum_mariadb_status_info type, ..)

Parameters:

    - data  Pointer passed with registration of callback function
            (usually a connection handle)
    - type  Information type  STATUS_TYPE or SESSION_TRACK_TYPE

Variadic Parameters:

 if (type == STATUS_TYPE):
    - server status (unsigned int)

 if (type == SESSION_TRACK_TYPE)
    - enum enum_session_state_type track_type - session track type

    if (track_type == SESSION_TRACK_SYSTEM_VARIABLES)
      - MARIADB_CONST_STRING *key
      - MARIADB_CONST_STRING *value

    else
      - MARIADB_CONST_STRING *value

` Note: Specifying a callback function overwrites the internal session tracking function, so API functions mysql_session_track_get_first()/next() can't be used.

An example can be found in unittest/libmariadb/connection.c (test_status_callback)

Addid in version 3.3.2

  • MARIADB_OPT_SKIP_READ_RESPONSE
    Don't read response packets in binary protocol.

Added in version 3.1.13

Replication/Binlog API options

  • MARIADB_OPT_RPL_REGISTER_REPLICA
    Specifies host name and port for Binlog/API. When this option was set, rpl_open() will register replica with server_id, host and port to the connected server. This information can be retrieved by SHOW SLAVE STATUS command. This option was added in version 3.3.1

TLS/SSL and Security options

  • MYSQL_OPT_SSL_KEY
    Specify the name of a key for a secure connection. If the key is protected with a passphrase, the passphrase needs to be specified with MARIADB_OPT_PASSPHRASE option.
  • MYSQL_OPT_SSL_CERT
    Specify the name of a certificate for a secure connection.
  • MYSQL_OPT_SSL_CA
    Specify the name of a file which contains one or more trusted CAs.
  • MYSQL_OPT_SSL_CAPATH
    Specify the path which contains trusted CAs.
  • MYSQL_OPT_SSL_CIPHER
    Specify one or more (SSLv3, TLSv1.0 or TLSv1.2) cipher suites for TLS encryption. Even if Connector/C supports TLSv1.3 protocol, it is not possible yet to specify TLSv1.3 cipher suites.
  • MYSQL_OPT_SSL_CRL
    Specify a file with a certificate revocation list.
  • MYSQL_OPT_SSL_CRLPATH
    Specify a directory with contains files with certificate revocation lists.
  • MARIADB_OPT_SSL_FP
    Specify the SHA1 fingerprint of a server certificate for validation during the TLS handshake.
  • MARIADB_OPT_SSL_FP
    Specify a file which contains one or more SHA1 fingerprints of server certificates for validation during the TLS handshake.
  • MARIADB_OPT_SSL_PASPHRASE
    Specify a passphrase for a passphrase protected client key.
  • MYSQL_OPT_SSL_VERIFY_SERVER_CERT
    Enable (or disable) the verification of the host name against common name (CN) of the server's host certificate.
  • MYSQL_SERVER_PUBLIC_KEY
    Specifies the name of the file which contains the RSA public key of the database server. The format of this file must be in PEM format. This option is used by the caching_sha2_password plugin and was added in Connector/C 3.1.0
  • MARIADB_OPT_TLS_CIPHER_STRENGTH
    This option is not in use anymore.
  • MARIADB_OPT_RESTRICTED_AUTH
    Specifies one or more comma separated authentication plugins which are allowed for authentication. If the database server asks for an authentication plugin not listed in this option, MariaDB Connector/C will return an error. This option was added in MariaDB Connector/C 3.3.0

Proxy settings

As per the proxy protocol specification, the connecting client can prefix its first packet with a proxy protocol header. The server will parse the header and assume the client's IP address is the one set in the proxy header.

  • MARIADB_OPT_PROXY_HEADER - specifies the proxy header which will be prefixed to the first packet. Parameters are void * for the prefix buffer and size_t for length of the buffer:
const char *hdr="PROXY TCP4 192.168.0.1 192.168.0.11 56324 443\r\n";
mysql_optionsv(mysql, MARIADB_OPT_PROXY_HEADER, hdr,  strlen(hdr));

Connection Attributes

Connection attributes are stored in the session_connect_attrs and session_account_connect_attrs Performance Schema tables. By default, MariaDB Connector/C sends the following connection attributes to the server:

  • _client_name: always "libmariadb"
  • _client_version: version of MariaDB Connector/C
  • _os: operation system
  • _pid: process id
  • _platform: e.g. x86 or x64
  • _server_host: the host name (as specified in mysql_real_connect). This attribute was added in Connector/C 3.0.5

Note: If the Performance Schema is disabled, connection attributes will not be stored on server.

  • MYSQL_OPT_CONNECT_ATTR_DELETE
    Deletes a connection attribute for the given key.
  • MYSQL_OPT_CONNECT_ATTR_ADD
    Adds a key/value pair to connection attributes. The total length of the stored connection attributes is limited to a maximum of 65535 bytes.
  • MYSQL_OPT_CONNECT_ATTR_RESET
    Clears the current list of connection attributes.

See Also

*mysql_init() *mysql_real_connect()

MariaDB Connector/C Reference

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