/*
This is the authfs daemon. It stores the user database and client
sessions, and it serves a 9P filesystem for managing them.

User data (usernames and password hashes) are stored on disk. Sessions
are stored in memory.
*/
package main

import (
	"context"
	"flag"
	"log"
	"net"
	"os"

	"github.com/docker-archive/go-p9p"
)

const (
	defaultNetwork = "unix"
	defaultAddress = "authfs.sock"
)

var (
	network, address string

	outlog = log.New(os.Stdout, "authfs [info]: ", log.LstdFlags)
	errlog = log.New(os.Stderr, "authfs [error]: ", log.LstdFlags|log.Llongfile)
)

func main() {
	flag.StringVar(&network, "net", defaultNetwork, "network transport protocol: {tcp, unix}")
	flag.StringVar(&address, "addr", defaultAddress, "IP address or Unix socket path to listen on")
	flag.Parse()

	ln, err := net.Listen(network, address)
	if err != nil {
		errlog.Fatal(err)
	}
	defer logErr(ln.Close())

	for {
		if conn, err := ln.Accept(); err == nil {
			outlog.Println("connected", conn.RemoteAddr())
			go handle(conn)
		} else {
			errlog.Println(err)
		}
	}
}

func handle(conn net.Conn) {
	defer logErr(conn.Close())
	ctx := context.Background()
	handler := p9p.Dispatch(NewSession())
	if err := p9p.ServeConn(ctx, conn, handler); err != nil {
		errlog.Printf("%v: %v\n", conn.RemoteAddr(), err)
	}
}

func logErr(err error) {
	if err != nil {
		errlog.Println(err)
	}
}