This is a part of fakeroot project.
Fakeroot runs a command in an environment were it appears to have
root privileges for file manipulation, by setting LD_PRELOAD to a
library with alternative versions of getuid(), stat(), etc. This
is useful for allowing users to create archives (tar, ar, .deb .rpm
etc.) with files in them with root permissions/ownership. Without
fakeroot one would have to have root privileges to create the
constituent files of the archives with the correct permissions and
ownership, and then pack them up, or one would have to construct
the archives directly, without using the archiver.

WWW: http://freshmeat.net/projects/fakeroot