ODBC means Open Database Connectivity, and defines a standard way of connecting to a database server such as MySQL, Postgres, SQL Server, Oracle, etc. Many of the these databases also provide their own native APIs for connectivity, in addition to supporting ODBC. Other databases provide ODBC support, but no support for native connectivity.
The ProFTPD distribution includes the
mod_sql_mysql module for
talking to a MySQL database using the native MySQL API, and a
mod_sql_postgres for connecting to Postgres databases using the
native Postgres API. However, there was no support for databases other
than these -- until now. The purpose of the
is to allow ProFTPD's
mod_sql module to connect to any
database that supports ODBC. This module also allows proftpd to work with
databases that may already provide APIs for native connectivity, but for
which a specific
mod_sql has not yet been developed.
This module is contained in the
mod_sql_odbc.c file for
ProFTPD 1.3.x, and is not compiled by default. Installation
instructions are discussed here.
The most current version of
mod_sql_odbc is distributed with
Please contact TJ Saunders <tj at castaglia.org> with any questions, concerns, or suggestions regarding this module.
SQLODBCVersion directive configures the ODBC API
version that the ODBC driver should use/expect. The default is
"ODBCv3", i.e. ODBC version 3. Some drivers may have issues with the
default version; this can manifest as errors similar to the following in your
message: '[unixODBC][Driver Manager]Driver does not support the requested version'When this happens, you might try using an older version of ODBC, via:
mod_sql_odbcrelies on one of the two following libraries for ODBC support:
http://www.iodbc.org http://www.unixodbc.orgOne of these ODBC libraries must be installed prior to using
Follow the usual steps for using contrib modules in ProFTPD, making sure to
mod_sql. Note that you will need to use the
LIBS environment variable for indicating which ODBC library
to link against.
For example, if you wish to use the unixODBC library, you would use:
$ ./configure LIBS=-lodbc --with-modules=mod_sql:mod_sql_odbc ... $ make $ make installOn the other hand, for using the iODBC library, the invocation is slightly different, specifying a different library name:
$ ./configure LIBS=-liodbc --with-modules=mod_sql:mod_sql_odbc ... $ make $ make install
You may need to specify the location of the ODBC header and library files in
configure command, e.g.:
$ ./configure \ LD_LIBRARY_PATH=/usr/local/odbc/lib \ LDFLAGS=-L/usr/local/odbc/lib \ LIBS=-lodbc \ --with-modules=mod_sql:mod_sql_odbc \ --with-includes=/usr/local/odbc/include \ --with-libraries=/usr/local/odbc/lib
What is ODBC?
ODBC (Open Data Base Connectivity) provides a way for client programs to access a wide range of databases or data sources.
ODBC is a standardized API, developed according to the specifications of the SQL Access Group, that allows one to connect to SQL databases. It defines a set of function calls, error codes and data types that can be used to develop database-independent applications. ODBC is usually used when database independence, or simultaneous access to different data sources, is required.
For more information about ODBC, refer to:
mod_sql_odbc be used?
There are two cases where a site might need to use the
module: when the site's database does not provide a native connectivity API
(e.g. FrontBase), and when the site's database does not have a
mod_sql_db module for it. For example,
ProFTPD does not have a
mod_sql_oracle module. Using
mod_sql_odbc and an Oracle-provided ODBC driver would allow
a site to have
proftpd communicate with their Oracle database.
How does ODBC work?
An ODBC driver is a dynamically loadable library that knows how to talk to a specific database. Many databases come bundled with an ODBC driver. The following lists where to find ODBC drivers for the popular MySQL and Postgres databases:
The ODBC driver manager is a library that manages communication between the ODBC-aware application and ODBC drivers. Its main functionality includes:
There are two environment variables that both the iODBC and unixODBC libraries use:
ODBCINI environment variable specifies the configuration file
used by the library; this file specifies the driver to use, and any database
connection information that driver may need.The
environment variable is used to tell the Driver Manager where it may find
the driver libraries. Note that on a Linux system, if the
/etc/ld.so.conf contains the directory where the ODBC driver
libraries live (and
/sbin/ldconfig has been run), use of
LD_LIBRARY_PATH setting may not be necessary.
The hard part about using the iODBC or unixODBC Unix driver managers is their configuration. Often in ODBC documentation you will mention of DSNs, or Data Source Names. A data source identifies a path to data that can include a network library, server, database, and other attributes. To connect to a data source, the driver manager checks for specific connection information. This specific connection information is recorded in a file usually called "odbc.ini".
[ODBC Data Sources] mysql = MySQL ODBC Connector (MyODBC) [mysql] Driver = /usr/local/iodbc/lib/libmyodbc3.so Description = MySQL Driver Server = localhost Database = proftpd Port = 3306 Socket = /tmp/mysql.sock
[mysql] Description = MySQL Driver = mysql Server = localhost Database = proftpd Port = 3306 Socket = /tmp/mysql.sockMore details on the contents of
odbc.inifiles, and the different meanings of configuration options, can be found in the respective driver manager documentation.
For the most part,
mod_sql_odbc requires little configuration.
It relies on the ODBC driver managers, which in turn use the above
environment variables. This means that
LD_LIBRARY_PATH can be set in the environment, before starting
mod_sql_odbc would then work. The
one required bit of information is the
This directive needs to contain the name of the stanza in your
odbc.ini file which holds the configuration. Using the example
odbc.ini files above, you would need the following in your
# Tells mod_sql to use mod_sql_odbc SQLBackend odbc # Tells mod_sql_odbc which odbc.ini stanza to use SQLConnectInfo mysql
Starting with proftpd 1.2.10rc1, it is possible to use the
configuration directives to set the environment variables directly in
proftpd.conf file, which makes configuration more
Example configuration using
<IfModule mod_sql_odbc.c> SetEnv LD_LIBRARY_PATH /path/to/odbc/lib SetEnv ODBCINI /path/to/
Once you have your ODBC driver configured properly, you can follow the rest of the instructions in the SQL howto for creating the schema for user/group authentication.
Please contact the author directly with any questions or comments.