In glibc 2.1 it appears that a daemon, utmpd, is required to
do utmp logging. In Rawhide 1.2.7-1.2.9 at least, it does
not appear to run by default, so it must be manually started
for any user logging to occur. Perhaps it should even
appear in /etc/inittab w/ respawn to prevent it from being
killed, rather than the initscripts? The approach of
logging who is on the system by a daemon seems to be rather
suspect to begin with....
Oops! It seems that utmpd is not needed, but the "who" command in the
current sh-utils reads /var/run/utmp rather than /var/run/utmpx
utmpd is not needed is you do not have legacy programs that want to
write directly to the utmp file.