#!/usr/bin/perl -w
# Version: 2003 07 09 - 17h45
# TODO:
#   . utiliser start-stop-daemon

use strict;
use File::Basename;


## CONFIGURATION
my $nfs_server = "prisme";            # the nfs server to connect to
my $nfs_server_user = "root";         # a valid username on the nfs server
my $use_version = "2";                # nfs-user-server uses 2, otherwise 3
                                      # would be better.  Check output of
                                      # 'rpcinfo -p <servername>'
my $pid_file = "/var/run/nfs-ssh-fw"; # fichier pid
my $serv_rep = "/home/nfs";           # répertoire exporté sur le serveur
my $client_rep = "/home/nfs";         # répertoire où monter le fs, sur le client
my $nfsd_client_port = "2818";        # we will port forward nfsd here
my $mountd_client_port = "3045";      # we will port forward mountd here
my $sleep_length = "86400";           # how long to sleep before restarting
                                      # 86400 secs is one day. Note
                                      # this is overridden if a command is
                                      # specified in the server's 
                                      # authorized_keys2 file
                    
# need to keep '-f', can also specify encryption algorithm, the ssh version
# and the id key 
my $ssh_opts = "-f -c blowfish -2 -i /root/.ssh/id_dsa_nfs";

my %rpcinfo_col = (               # change as per output of rpcinfo -p
    'program'     => '0',
    'version'     => '1',
    'protocol'     => '2',
    'port'        => '3',
    'daemon'    => '4'
);

## END CONFIGURATION

# start
if ($ARGV[0] eq "start")
{
    # Quitter si le démon tourne déjà
    if (-s $pid_file)
    {
      print ("nfs-ssh-fw est déjà lancé.\n");
      exit 1;
    }

    my $prog_name = basename($0);
    my $nfsd_server_port = "";
    my $mountd_server_port = "";

    # for signals
    $SIG{INT} = sub { die "$0 interrupted and dying (does not kill ssh)\n" };
    print "$prog_name: Starting ssh/nfs forwarding \n";

    # first, get the rpcinfo<p>
    my @rpcinfo = `rpcinfo -p $nfs_server`;
    print "My rpcinfo =\n @rpcinfo";

    # now get the nfsd and mountd port numbers
    foreach (@rpcinfo) {
        my @line = split;
        if ($line[$rpcinfo_col{"version"}] eq $use_version &&
            $line[$rpcinfo_col{"daemon"}] eq "nfs" &&
            $line[$rpcinfo_col{"protocol"}] eq "tcp") {
                $nfsd_server_port = $line[$rpcinfo_col{"port"}];
            print (" nfsd port = $nfsd_server_port");
        } elsif ($line[$rpcinfo_col{"version"}] eq $use_version &&
            $line[$rpcinfo_col{"daemon"}] eq "mountd" &&
            $line[$rpcinfo_col{"protocol"}] eq "tcp") {
                $mountd_server_port = $line[$rpcinfo_col{"port"}];
            print (", mountd port = $mountd_server_port\n");
        }
    }

    # on met en place le ssh-forwarding
    system("/usr/bin/ssh $ssh_opts -L \\
       $nfsd_client_port:$nfs_server:$nfsd_server_port -L \\
       $mountd_client_port:$nfs_server:$mountd_server_port -l \\
       $nfs_server_user $nfs_server /bin/sleep $sleep_length");

    # attendre que le ssh-forwarding se mette en place,
    # puis monter le répertoire
    print ("Pause de 5 secondes...\n");
    system("/bin/sleep 5 &&
       /bin/mount -t nfs -o tcp,port=$nfsd_client_port,mountport=$mountd_client_port,rsize=8192,wsize=8192,intr,rw,bg,nosuid localhost:$serv_rep $client_rep");
    `ps aux | grep "[/]usr/bin/ssh -f -c blowfish -2 -i /root/.ssh/id_dsa_nfs" | awk '{print \$2}' > $pid_file`;

    print ("nfs-ssh-fw lancé; pid = ");
    print (`cat $pid_file`);
    exit 0;
}

elsif ($ARGV[0] eq "stop")
{
    
    # Quitter si le démon ne tourne pas
    if (! -s $pid_file)
    {
      print ("nfs-ssh-fw ne tourne pas.\n");
      exit 1;
    }
    
    print ("Arrêt de nfs-ssh-fw...\n");
    
    # démonter /home/nfs si et seulement si il est monté
    my $mounted=`mount | grep "rw,nosuid,tcp,port=$nfsd_client_port,mountport=$mountd_client_port" | awk '{print \$3}'`;
    if ($mounted ne "")
    {
      print ("  - démontage de $client_rep\n");
      `/bin/umount $client_rep`;
    }
    
    # killer le ssh-forwarding
    print ("  - arrêt du ssh\n");
    my $pid=`cat $pid_file`;
    kill 15, $pid;
    unlink $pid_file;
    print ("nfs-ssh-fw arrêté.\n");
    exit 0;
}

elsif ($ARGV[0] eq "restart")
{
    system("/etc/init.d/nfs-ssh-fw.pl stop");
    system("/etc/init.d/nfs-ssh-fw.pl start");
    exit 0;
}

# autre
else
{
    print ("Usage: /etc/init.d/nfs-ssh-fw.pl {start|stop|restart}");
    exit 1;
}