What is this?

An example override of the libc function gethostname(2).

How do I use it?

• build the shared library (make) or the RPM (make rpm)
• install it somewhere (make install) or (rpm -ivh .../path/to/new-rpm)
• either:
  • set the installed shared library to be loaded prior to libc (export LD_PRELOAD=/path/to/shared/library.so.1)
  • set the environment variable MYHOSTNAME to whatever hostname you want (note HOST_NAME_MAX is usually 64 characters)
  • run your application normally
• or
  • use the included fakehostname wrapper to launch your application

If you don't set $MYHOSTNAME, the actual hostname returned by the real gethostname(2) call will be used

Wrapper Script

I also wrote a little wrapper script called fakehostname which you can install in your $PATH (eg /usr/local/bin) which will set LD_PRELOAD for you and call your binary with the hostname set:

fakehostname <pretend-hostname> <original-command> [original-command-args]

License

This code is licensed under the GPLv3 -- a copy of the license can be found in the file LICENSE.