docs: add FreeBSD build and service setup guide

FREEBSD.md

@@ -0,0 +1,123 @@
+# Running finger on FreeBSD
+
+Tested on FreeBSD 15.0-RELEASE using clang 19, meson, and ninja inside a Bastille thin jail.
+
+## Dependencies
+
+```sh
+pkg install git meson ninja pkgconf boost-all googletest
+```
+
+## Build
+
+```sh
+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.
+
+```sh
+mkdir -p /var/finger/users
+echo "Out to lunch." > /var/finger/users/pete
+```
+
+Test locally:
+
+```sh
+printf 'pete\r\n' | nc -w 2 127.0.0.1 79
+```
+
+## RC Service
+
+Create `/usr/local/etc/rc.d/fingerd`:
+
+```sh
+#!/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"
+```
+
+```sh
+chmod +x /usr/local/etc/rc.d/fingerd
+```
+
+Enable at boot and start:
+
+```sh
+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:
+
+```sh
+bastille cmd finger sh -c 'cd /usr/local/src/finger && meson compile -C builddir && meson install -C builddir'
+```