use Socket;
use strict;
use POSIX qw(setsid);

my @hosts = ('foo.com', 'bar.org');
my $host;
my $kidpid;

# daemonize the program
&daemonize;

foreach $host (@hosts){
    sshPush( $host ); 
}

sub sshPush {
    my $host = shift;
    my $cmd = "/opt/local/bin/hg push --ssh \"/opt/local/bin/ossh -i /path/to/id_dsa\" ssh://UserName@".$host."/TWiki";
    chdir '/path/to/TWiki'                 or die "Can't chdir to /: $!";
   
    if (TryConnect( $host )) {
	if (!defined($kidpid = fork())) {
# fork returned undef, so failed
	    die "cannot fork: $!";
	} elsif ($kidpid == 0) {
# fork returned 0, so this branch is the child
	    exec($cmd);
# if the exec fails, fall through to the next statement
	    die "can't exec push: $!";
	}
    }
    chdir '/'    or die "Can't chdir to /: $!";
}
sub TryConnect
{
        my $port = 22;
        my $host = shift || 'localhost';

        my $iaddr;
        if (!($iaddr = inet_aton($host))) {
                return 0;
        }

        my $paddr = sockaddr_in($port, $iaddr);
        my $result;
        eval {
                local $SIG{ALRM} = sub { die "alarm\n" }; # NB: \n required
                alarm 7;
                socket(SOCK, &AF_INET, &SOCK_STREAM, 0) || die "socket: $!";
                $result = connect(SOCK, $paddr);
                close(SOCK);
                alarm 0;
        };
        if ($@) {
                die "$@" unless $@ eq "alarm\n";
                # timed out
        }

        return $result;
}

sub daemonize {
    chdir '/'                 or die "Can't chdir to /: $!";
    open STDIN, '/dev/null'   or die "Can't read /dev/null: $!";
    open STDOUT, '>>/zstore/timpush.log' or die "Can't write to /dev/null: $!";
    open STDERR, '>>/zstore/timpush.log' or die "Can't write to /dev/null: $!";
    defined(my $pid = fork)   or die "Can't fork: $!";
    exit if $pid;
    setsid                    or die "Can't start a new session: $!";
    umask 0;
}