source: freewrt/package/sleepshell/ipkg/sleepshell.postinst@ 621d5d2

#!/bin/sh
. $IPKG_INSTROOT/etc/functions.sh

get_gid_from_group() {
        gid=-1
        gid=$(grep "^$1:" $IPKG_INSTROOT/etc/group 2>/dev/null \
            |awk '{FS=":"}{print $3}')
        echo $gid
}

get_uid_from_user() {
        uid=$(grep "^$1:" $IPKG_INSTROOT/etc/passwd 2>/dev/null \
            | awk '{FS=":"}{print $3}')
        echo $uid
}

get_gid_from_user() {
        gid=$(grep "^$1:" $IPKG_INSTROOT/etc/passwd 2>/dev/null \
            | awk '{FS=":"}{print $4}')
        echo $gid
}

shell_exists() {
        grep -q "^$1$" $IPKG_INSTROOT/etc/shells 2>&-
        return $?
}

add_shell() {
        shell_exists $1 || {
                echo "adding shell $1 to /etc/shells"
                echo "$1" >>$IPKG_INSTROOT/etc/shells
        }
}


NEWUSER=rssh
NEWGROUP=rssh
NEWHOME="/home/$NEWUSER"

if ! group_exists $NEWGROUP
then
        GID=$(get_next_gid)
        add_group $NEWGROUP $GID
fi

if user_exists $NEWUSER
then
        UID=$(get_uid_from_user $NEWUSER)
        GID=$(get_gid_from_user $NEWUSER)
else
        UID=$(get_next_uid)
        add_user $NEWUSER $UID $GID "$NEWHOME" "/bin/sleepshell"
fi

if [ ! -d "$NEWHOME" ]
then
        mkdir -p "$NEWHOME/.ssh"
        touch "$NEWHOME/.ssh/authorized_keys"
        chown $UID:$GID "$NEWHOME" "$NEWHOME/.ssh" "$NEWHOME/.ssh/authorized_keys"
        chmod 750 "$NEWHOME"
        chmod 700 "$NEWHOME/.ssh"
        chmod 400 "$NEWHOME/.ssh/authorized_keys"
fi

add_shell /bin/sleepshell