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DBI::ProxyServer

NAME

SYNOPSIS

    use DBI::ProxyServer;
    DBI::ProxyServer::main(@ARGV);

DESCRIPTION

DBI::ProxyServer runs as a daemon on the machine with the DBMS or on the firewall. The client connects to the agent using the DBI driver DBD::Proxy, thus in the exactly same way than using DBD::mysql, DBD::mSQL or any other DBI driver.

The agent is implemented as a RPC::PlServer application. Thus you have access to all the possibilities of this module, in particular encryption and a similar configuration file. DBI::ProxyServer adds the possibility of query restrictions: You can define a set of queries that a client may execute and restrict access to those. (Requires a DBI driver that supports parameter binding.) See ``CONFIGURATION FILE''.  

OPTIONS

chroot (--chroot=dir)

(UNIX only) After doing a bind(), change root directory to the given directory by doing a chroot(). This is usefull for security, but it restricts the environment a lot. For example, you need to load DBI drivers in the config file or you have to create hard links to Unix sockets, if your drivers are using them. For example, with MySQL, a config file might contain the following lines:

    my $rootdir = '/var/dbiproxy';
    my $unixsockdir = '/tmp';
    my $unixsockfile = 'mysql.sock';
    foreach $dir ($rootdir, "$rootdir$unixsockdir") {
        mkdir 0755, $dir;
    }
    link("$unixsockdir/$unixsockfile",
         "$rootdir$unixsockdir/$unixsockfile");
    require DBD::mysql;

    {
        'chroot' => $rootdir,
        ...
    }

If you don't know chroot(), think of an FTP server where you can see a certain directory tree only after logging in. See also the --group and --user options.

clients

An array ref with a list of clients. Clients are hash refs, the attributes accept (0 for denying access and 1 for permitting) and mask, a Perl regular expression for the clients IP number or its host name. See ``Access control'' below.

configfile (--configfile=file)

Config files are assumed to return a single hash ref that overrides the arguments of the new method. However, command line arguments in turn take precedence over the config file. See the ``CONFIGURATION FILE'' section below for details on the config file.

debug (--debug)

Turn debugging mode on. Mainly this asserts that logging messages of level ``debug'' are created.

facility (--facility=mode)

(UNIX only) Facility to use for ``Sys::Syslog (3)''. The default is daemon.

group (--group=gid)

After doing a bind(), change the real and effective GID to the given. This is usefull, if you want your server to bind to a privileged port (<1024), but don't want the server to execute as root. See also the --user option.

GID's can be passed as group names or numeric values.

localaddr (--localaddr=ip)

By default a daemon is listening to any IP number that a machine has. This attribute allows to restrict the server to the given IP number.

localport (--localport=port)

This attribute sets the port on which the daemon is listening. It must be given somehow, as there's no default.

logfile (--logfile=file)

Be default logging messages will be written to the syslog (Unix) or to the event log (Windows NT). On other operating systems you need to specify a log file. The special value ``STDERR'' forces logging to stderr. See Net::Daemon::Log(3) for details.

mode (--mode=modename)

The server can run in three different modes, depending on the environment.

If you are running Perl 5.005 and did compile it for threads, then the server will create a new thread for each connection. The thread will execute the server's Run() method and then terminate. This mode is the default, you can force it with ``--mode=threads''.

If threads are not available, but you have a working fork(), then the server will behave similar by creating a new process for each connection. This mode will be used automatically in the absence of threads or if you use the ``--mode=fork'' option.

Finally there's a single-connection mode: If the server has accepted a connection, he will enter the Run() method. No other connections are accepted until the Run() method returns (if the client disconnects). This operation mode is usefull if you have neither threads nor fork(), for example on the Macintosh. For debugging purposes you can force this mode with ``--mode=single''.

pidfile (--pidfile=file)

(UNIX only) If this option is present, a PID file will be created at the given location. Default is do not create a pidfile.

user (--user=uid)

After doing a bind(), change the real and effective UID to the given. This is usefull, if you want your server to bind to a privileged port (<1024), but don't want the server to execute as root. See also the --group and the --chroot options.

UID's can be passed as group names or numeric values.

version (--version)

Supresses startup of the server; instead the version string will be printed and the program exits immediately.

CONFIGURATION FILE

The config file is a Perl script. At the top of the file you may include arbitraty Perl source, for example load drivers at the start (usefull to enhance performance), prepare a chroot environment and so on.

The important thing is that you finally return a hash ref of option name/value pairs. The possible options are listed above.

All possibilities of Net::Daemon and RPC::PlServer apply, in particular

Host and/or User dependent access control

Host and/or User dependent encryption

Changing UID and/or GID after binding to the port

Running in a chroot() environment

Additionally the server offers you query restrictions. Suggest the following client list:

    'clients' => [
        { 'mask' => '^admin\.company\.com$',
          'accept' => 1,
          'users' => [ 'root', 'wwwrun' ],
        },
        {
          'mask' => '^admin\.company\.com$',
          'accept' => 1,
          'users' => [ 'root', 'wwwrun' ],
          'sql' => {
               'select' => 'SELECT * FROM foo',
               'insert' => 'INSERT INTO foo VALUES (?, ?, ?)'
               }
        }

    $sth->prepare("select");

    $sth->prepare("insert");

AUTHOR

    Copyright (c) 1997    Jochen Wiedmann
                          Am Eisteich 9
                          72555 Metzingen
                          Germany

                          Email: joe@ispsoft.de
                          Phone: +49 7123 14881

SEE ALSO

Index

NAME

SYNOPSIS

DESCRIPTION

OPTIONS

CONFIGURATION FILE

AUTHOR

SEE ALSO