I straced pwcheck and inetd (which pop3d is working from) and saw that
the former tries to open /var/run/pwcheck/pwcheck, and the latter
connects to /var/state/pwcheck/pwcheck.
As a workaround, I ln -s ../state/pwcheck /var/run, and it works. But I
don't understand what has happened. I've searched the archives and read
/usr/share/doc/libsasl7/sysadmin.html, but I can't see how pop3d knows
that it should use pwcheck and not anything else, or why pwcheck started
to look for /var/run/pwcheck instead of /var/state/pwcheck. Could anyone
please explain what has happened, and possibly point me to the proper
solution?