Running finger on FreeBSD

Tested on FreeBSD 15.0-RELEASE using clang 19, meson, and ninja inside a Bastille thin jail.

Dependencies

pkg install git meson ninja pkgconf boost-all googletest

Build

git clone https://github.com/waffle2k/finger /usr/local/src/finger
cd /usr/local/src/finger
meson setup builddir
meson compile -C builddir
meson install -C builddir

meson install places the binary at /usr/local/bin/finger.

Plan Files

Create one file per username under /var/finger/users/. The file contents are returned when that user is fingered.

mkdir -p /var/finger/users
echo "Out to lunch." > /var/finger/users/pete

Test locally:

printf 'pete\r\n' | nc -w 2 127.0.0.1 79

RC Service

Create /usr/local/etc/rc.d/fingerd:

#!/bin/sh
# PROVIDE: fingerd
# REQUIRE: NETWORKING
# KEYWORD: shutdown

. /etc/rc.subr

name="fingerd"
rcvar="fingerd_enable"
command="/usr/local/bin/finger"
pidfile="/var/run/fingerd.pid"
command_interpreter=""

start_cmd="fingerd_start"
stop_cmd="fingerd_stop"
status_cmd="fingerd_status"

fingerd_start() {
    echo "Starting ${name}."
    /usr/sbin/daemon -p ${pidfile} -f ${command}
}

fingerd_stop() {
    if [ -f ${pidfile} ]; then
        echo "Stopping ${name}."
        kill $(cat ${pidfile}) && rm -f ${pidfile}
    else
        echo "${name} is not running."
    fi
}

fingerd_status() {
    if [ -f ${pidfile} ] && kill -0 $(cat ${pidfile}) 2>/dev/null; then
        echo "${name} is running as pid $(cat ${pidfile})."
    else
        echo "${name} is not running."
    fi
}

load_rc_config $name
run_rc_command "$1"

chmod +x /usr/local/etc/rc.d/fingerd

Enable at boot and start:

sysrc fingerd_enable=YES
service fingerd start

Bastille Jail Setup (optional)

If running inside a Bastille thin jail, bind-mount the plan files directory from the host so they can be managed without entering the jail.

Host fstab (/usr/local/bastille/jails/finger/fstab):

/srv/finger/users  /usr/local/bastille/jails/finger/root/var/finger/users  nullfs  rw  0  0

To redirect external port 79 into the jail, add to /usr/local/bastille/jails/finger/rdr.conf:

dual re0 any any tcp 79 79

pf will apply this as:

rdr pass on re0 inet proto tcp from any to any port = finger -> <jail-ip> port 79

Rebuild after source changes:

bastille cmd finger sh -c 'cd /usr/local/src/finger && meson compile -C builddir && meson install -C builddir'

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