smtpd table backend serving local password hashes
table-shadow is a proc-table backend for smtpd(8), answering the
credentials service: for an SMTP AUTH login it returns the password hash
of the matching local account, and smtpd checks the password itself with
crypt_checkpass(3). The "@domain" part of the login is stripped, so both
"user" and "user@domain" map to the Unix account "user".

The hash is read with getpwnam_shadow(3), so the backend is installed
setgid _shadow, executable by its owner _smtpd alone. It reads nothing
but the two passwd databases, unveil(2) being applied at startup.

Maintainer: Jean-Gerard Pailloncy <j-g@pailloncy.com>
