ttyd-login

#!/bin/sh
set -e

script_name=$(basename "$0")
remote_addr="$1"
hostname=$(hostname)
error_pipe="${TMPDIR:-/tmp}/$script_name.$$.pipe"
error_log="${TMPDIR:-/tmp}/$script_name.$$.stderr"

cleanup() {
  trap - TERM
  rm -f -- "$error_pipe" "$error_log"
}

trap cleanup TERM EXIT

[ ! -z "$remote_addr" ] && echo "Connecting to $hostname from $remote_addr."

read -rp "$hostname login: " ssh_user
touch "$error_log"
mkfifo "$error_pipe"
tee -a "$error_log" < "$error_pipe" >&2 &
ssh -o PreferredAuthentications=password -l "$ssh_user" "$hostname" 2>"$error_pipe" || true

failures=$(grep -ic "too many authentication failures" "$error_log")

if [ $failures -gt 0 ] && [ ! -z "$remote_addr" ]; then
  logger -p auth.err -t "$script_name" "error: maximum authentication attempts exceeded for $ssh_user from $remote_addr"
fi

sleep 3