#!/bin/bash

# instant-rsyncd lets you quickly set up and start a simple, unprivileged rsync
# daemon with a single module in the current directory.  I've found it
# invaluable for quick testing, and I use it when writing a list of commands
# that people can paste into a terminal to reproduce a daemon-related bug.
# Sysadmins deploying an rsync daemon for the first time may find it helpful as
# a starting point.
#
# Usage: instant-rsyncd MODULE PORT RSYNCD-USERNAME [RSYNC-PATH]
# The script asks for the rsyncd user's password twice on stdin, once to set it
# and once to log in to test the daemon.
# -- Matt McCutchen <matt@mattmccutchen.net>

set -e

dir="$(pwd)"

if [ "$#" -lt 3 ]; then
	echo "I would install an rsync daemon in $dir if you gave me"
	echo "a module name, a port, and an rsync username."
	exit 1
fi

module="$1"
port="$2"
user="$3"
rsync="$4"
if [ ! "$rsync" ]; then
	rsync=rsync
fi

moduledir="${dir%/}/$module"

echo
echo "I'm about to install an rsync daemon in $dir."
echo "It will listen on port $port for requests giving rsync username $user"
echo "and the password you are about to specify.  It will serve a module"
echo "$module corresponding to $moduledir."
echo

IFS='' read -s -p 'Desired password: ' password

mkdir "$module"

cat >rsyncd.conf <<EOF
log file = rsyncd.log
pid file = rsyncd.pid
port = $port
use chroot = no

[$module]
	path = $module
	read only = false
	auth users = $user
	secrets file = $module.secrets
EOF

touch "$module".secrets
chmod go-rwx "$module".secrets
cat >"$module".secrets <<EOF
$user:$password
EOF

cat >start <<EOF
#!/bin/bash
set -e
cd \`dirname \$0\`
! [ -e rsyncd.pid ] || {
	echo "Is the daemon already running?  If not, delete rsyncd.pid."
	exit 1
}
$rsync --daemon --config=rsyncd.conf
EOF
chmod +x start

cat >stop <<"EOF"
#!/bin/bash
set -e
cd `dirname $0`
! [ -e rsyncd.pid ] || kill -s SIGTERM $(< rsyncd.pid)
EOF
chmod +x stop

path="rsync://$user@$(hostname):$port/$module/"

if ./start; then
	sleep .2
	echo
	echo "I tried to start the daemon.  The log file rsyncd.log says:"
	echo
	cat rsyncd.log
	echo
	echo "You can start and stop it with ./start and ./stop respectively."
	echo "You can customize the configuration file rsyncd.conf."
	echo
	echo "Give rsync the following path to access the module:"
	echo "    $path"
	echo
	echo "Let's test the daemon now.  Enter the password you chose."
	echo '$' $rsync --list-only "$path"
	$rsync --list-only "$path"
	echo
	echo "You should see an empty folder; it's $moduledir."
else
	echo "Something went wrong.  Do you see an error message?"
fi