send it to the socket as a string of bytes preceded by a four-byte length
string packed in binary using ``struct.pack('>L', n)``.
+ .. note:: Because portions of the configuration are passed through
+ :func:`eval`, use of this function may open its users to a security risk.
+ While the function only binds to a socket on ``localhost``, and so does
+ not accept connections from remote machines, there are scenarios where
+ untrusted code could be run under the account of the process which calls
+ :func:`listen`. Specifically, if the process calling :func:`listen` runs
+ on a multi-user machine where users cannot trust each other, then a
+ malicious user could arrange to run essentially arbitrary code in a
+ victim user's process, simply by connecting to the victim's
+ :func:`listen` socket and sending a configuration which runs whatever
+ code the attacker wants to have executed in the victim's process. This is
+ especially easy to do if the default port is used, but not hard even if a
+ different port is used).
.. function:: stopListening()
:class:`Formatter` subclass. Subclasses of :class:`Formatter` can present
exception tracebacks in an expanded or condensed format.
+.. note:: Due to the use of :func:`eval` as described above, there are
+ potential security risks which result from using the :func:`listen` to send
+ and receive configurations via sockets. The risks are limited to where
+ multiple users with no mutual trust run code on the same machine; see the
+ :func:`listen` documentation for more information.