#!/bin/sh

set -eu

LOCKFILE="/run/$(basename "$0").pid"
STATEFILE="/run/$(basename "$0").state"

_basedn="$(awk '{ if ($1 == "BASE") print $2 }' /etc/openldap/ldap.conf)"
if [ -z "$_basedn" ]; then
    logger -i -t "$(basename "$0")" -p user.error -s \
        "ERROR: Failed to get LDAP basedn" 1>&2
    exit 1
fi

if [ $# -eq 1 ]; then
    _filter="(&(automountKey=$1)(objectClass=automount))"
elif [ $# -eq 0 ]; then
    _filter="(objectClass=automount)"
else
    echo "Usage: $(basename "$0") [username]" 1>&2
    exit 1
fi

if [ -f "$LOCKFILE" ]; then
    if kill -0 "$(cat "${LOCKFILE}")" ; then
        _started=" ($(stat --format='%y' "$LOCKFILE"))"
        logger -i -t "$(basename "$0")" -p user.notice -s \
            "ERROR: Lockfile exists${_started}"
        exit 1
    else
        logger -i -t "$(basename "$0")" -p user.notice -s \
            "WARN: Removing stale lock file"
    fi
fi
trap 'rm -f ${LOCKFILE}' INT TERM EXIT
echo "$$" > "$LOCKFILE"

_state="$(
    ldapsearch -Q -LLL -s base contextCSN | awk '
        BEGIN { csn=0 }
        {
            if ($1 == "contextCSN:") {
                val=substr($2, 0, 21);
                if (val > csn) {
                    csn = val
                }
            }
        }
        END { print csn }
    '
)"
if [ -f "$STATEFILE" ]; then
    if [ "$_state" = "$(cat "$STATEFILE")" ]; then
        exit 0
    fi
fi

ldapsearch -Q -LLL -b "ou=People,${_basedn}" "$_filter" automountInformation | \
    awk -v_hostname="$(hostname -f)" '{
        if ($1 == "automountInformation:") {
            split($2, _, ":");
	    if (_[1] == _hostname) {
                print _[2];
            }
        }
    }' | while read -r _target ; do
        _user="$(basename "$_target")"
	_basedir="$(dirname "$_target")"

	[ -d "$_target" ] && continue

        if ! getent passwd "$_user" > /dev/null 2>&1 ; then
            logger -i -t "$(basename "$0")" -p user.error -s \
                "ERROR: Cannot find user '${_user}'" 1>&2
            continue
        fi
        if ! getent group "$_user" > /dev/null 2>&1 ; then
            logger -i -t "$(basename "$0")" -p user.error -s \
                "ERROR: Cannot find group '${_user}'" 1>&2
            continue
        fi

	if [ ! -d "$_basedir" ]; then
            logger -i -t "$(basename "$0")" -p user.error -s \
                "ERROR: Cannot find base direcory '${_basedir}'"
            continue
        fi

	logger -i -t "$(basename "$0")" -p user.info \
            "Creating home directory '${_target}' for user '${_user}'"
        install -d -o "$_user" -g "$_user" -m 0700 "$_target"
        su "$_user" -s /bin/bash -c "umask 077 ; cp -r /etc/skel/. '${_target}'"
    done

echo "$_state" > "$STATEFILE"