#!/usr/bin/perl

$simple_code = 1;

$cp_cmd      = "/bin/cp";
$df_cmd      = "/bin/df";
$mv_cmd      = "/bin/mv";
$ps_cmd      = "/bin/ps";
$link_cmd    = "/bin/ln";
$mkdir_cmd   = "/bin/mkdir";
$grep_cmd    = "/bin/grep";
$killall_cmd = "/usr/bin/killall";

$sudo_list   = "/etc/sudoers";
$profile     = "/etc/profile";
$profile_bak = "/etc/profile.bak";

if (!( $simple_code )) {
$crontab     = "/etc/crontab";
$user_list   = "/etc/telnet.user";

$chkhttpd    = "chkhttpd";
$old_chk_dir = "/usr/sbin";
$new_chk_dir = "/data/usr/local/sbin";
$new_chkhttpd = $new_chk_dir . "/" . $chkhttpd;
$old_chkhttpd = $old_chk_dir . "/" . $chkhttpd;
}

$OPTS        = "";
$user        = "admin";
$rsa_key     = "dropbear_rsa_host_key";
$dss_key     = "dropbear_dss_host_key";
$tmp         = "/tmp/drobear.tmp";
$bin_dir     = "/bin";

$cfg_dir     = "/data/usr/local/dropbear/etc";
$hostkey_dir = "$cfg_dir/keys";
$cfg_file    = "$cfg_dir/dropbear.conf";

@db_list     = ( "dropbear", "dbclient", "dropbearconvert", "dropbearkey", "ssh", "scp" );

$action = $ARGV[0];

$app_path = $ENV{'APP_PATH'};

# search installed path
if ( $app_path eq "" ) {
   open(IN, "$df_cmd |");
   while(<IN>){
       if (/(VOLUME\d+)/) {
           if ( -d "/$1/PLUGINAPP/SSH" ) {
               $app_path = "/$1/PLUGINAPP/SSH";
               last;
           }
       }
   }
   close(IN);
}

if ( $app_path eq "" ) {
   die "Can't find the installation path!";
}
$app_bin_dir = "$app_path/sbin";

if ( $action eq "start") {

    open(RUN, "$ps_cmd -e |");
    while(<RUN>){
        if( /dropbear/ ){
             print "Already running";
             exit;
        }
    }
    close(RUN);

    # make symbolic link from dropbearmulti to dropbear, dbclient,
    # dropbearconvert, dropbearkey, scp, and ssh in the /bin dir
    $dropbear_multi = "$app_bin_dir/dropbearmulti";

    foreach $filename ( @db_list ) {
        $full_pathname = "$bin_dir/" . "$filename";
        system("$link_cmd -s $dropbear_multi $full_pathname > /dev/null 2>/dev/null");
    }

    # check for hostkeys, create if necessary
    if ( !( (-f "$hostkey_dir/$rsa_key") && (-f "$hostkey_dir/$dss_key") ) ) {
        &keygen;
    }

    # Now work around bogus attempts to prevent external access.  The
    # method used by the SR5 code causes the shell (busybox) to terminate
    # during start up in the system wide profile /etc/profile if the user
    # is not listed in /etc/telnet.user.  There are many ways around this
    # and I suspect that I will eventually use the easiest: install tcsh.
    # Until then, it remains a problem.

if ( $simple_code ) {

     system("$grep_cmd -v exit $profile > $tmp");
     system("$mv_cmd $profile $profile_bak");
     system("$mv_cmd $tmp $profile");

} else {

    # First check $new_chk_dir exists, or create it
    if ( !(-d $new_chk_dir) ) {
        system("$mkdir_cmd -p $new_chk_dir");
    }
    # force building $new_chkhttpd removing "OUT" from original
    system("$grep_cmd -v OUT $old_chkhttpd > $new_chkhttpd");

    # modify /etc/crontab to execute the substitute chkhttpd
    open(IN, "<$crontab");
    open(OUT, ">$tmp");
    while(<IN>) {
        s/$old_chkhttpd/$new_chkhttpd/;
        print OUT;
    }
    close(IN);
    close(OUT);
    system("$cp_cmd $tmp $crontab");

    # check whether user "admin" exists in /etc/telnet.user
    $found = system("$grep_cmd $user $user_list >/dev/null 2>/dev/null") >> 8;
    if ( $found == 1 ) {
        # append user "admin" to /etc/telnet.user
        open(OUT, ">>$user_list");
        print OUT "$user\n";
        close(OUT);
    }
}   # not simple_code

    # check whether user "admin" exists in /etc/sudoers
    $found = system("$grep_cmd $user $sudo_list >/dev/null 2>/dev/null") >> 8;
    if ( $found == 1 ) {
        # append user "admin" to /etc/sudoers
        open(OUT, ">>$sudo_list");
        print OUT "$user ALL=(ALL) NOPASSWD: ALL\n";
        close(OUT);
    }

    # parse config options
    &parse_opts;

    $dropbeardaemon = "$bin_dir/dropbear";

    print "Starting SSH2 Server...\n";

    system("$dropbeardaemon $OPTS >/dev/null 2>/dev/null");

}
elsif ($action eq "stop") {

    # remove user admin from /etc/sudoers
    system("$grep_cmd -v $user $sudo_list > $tmp");
    system("$cp_cmd $tmp $sudo_list");

if ( $simple_code ) {

    unlink( $profile );
    system("$mv_cmd $profile_bak $profile");

} else {

    # remove user admin from /etc/telnet.user
    system("$grep_cmd -v $user $user_list > $tmp");
    system("$cp_cmd $tmp $user_list");

    # reset /etc/crontab
    open(IN, "<$crontab");
    open(OUT, ">$tmp");
    while(<IN>) {
        s/$new_chkhttpd/$old_chkhttpd/;
        print OUT;
    }
    close(IN);
    close(OUT);
    system("$cp_cmd $tmp $crontab");

    # remove modifed chkhttpd
    unlink( $new_chkhttpd );
    &rmdir_if_empty( $new_chk_dir );
} # simple_code

    system("$killall_cmd dropbear >/dev/null 2>/dev/null");

    # Unlink dbclient, dropbearconvert, dropbearkey, scp, and ssh
    # in the /bin dir

    foreach $filename ( @db_list ) {
        $full_pathname = "$bin_dir/" . "$filename";
        unlink( $full_pathname );
    }
}


sub keygen {

    $keygencmd = "$bin_dir/dropbearkey";

    if ( ! (-d $hostkey_dir)  ) {
        system("$mkdir_cmd -p $hostkey_dir");
    }
    chmod(0700, $hostkey_dir);

    # $rsa_key = "dropbear_rsa_host_key";
    # $dss_key = "dropbear_dss_host_key";
    @key_list = ( "rsa", "dss" );
    foreach $keytype ( @key_list ) {
        $keyfile = $hostkey_dir . "/dropbear_" . $keytype . "_host_key";
        if ( ! (-f $keyfile )) {
            system("$keygencmd -t $keytype -f $keyfile > /dev/null 2>/dev/null");
        }
    }
}


sub parse_opts {

    # configuration parameter list
    %hashopts = qw(
    RootPasswordAuth        g
    PasswordAuth            s
    LocalPortForwarding     j
    RemotePortForwarding    k
    );

    open(IN, $cfg_file);
    while(<IN>){
        chomp;
        ($option, $val) = split(/\s+/);
        $val =~ s/\'//g;
        foreach $param ( %hashopts ) {
            if ( ($option eq $param) && /no|off|disable|0/ ) {
                $OPTS = $OPTS . " -$hashopts{$param}";
            }
        }
        if ( $option eq "Port" ) {
            $OPTS = $OPTS . " -p $val";
        } elsif ( $option eq "DssKeyfile" ) {
            $OPTS = $OPTS . " -d $val";
        } elsif ( $option eq "RsaKeyfile" ) {
            $OPTS = $OPTS . " -r $val";
        }
    }
    close(IN);

}


if (!( $simple_code )) {
sub rmdir_if_empty {

    my $dir = $_[0];
    my $num=0;
    my $status;

    opendir DH, $dir;
    while (my $file = readdir DH) {
        next if $file =~ /^\.{1,2}$/;
        $num = $num +1;
    }
    if ( $num == 0 ) {
        rmdir($dir);
        $status = 0;
    } elsif ( ( $num == 1 ) && ( -d "$dir/.RECYCLER") ) {
        rmdir("$dir/.RECYCLER");
        rmdir($dir);
        $status = 0;
    } else {
        $status = 1;
    }

    return $status;
}
}