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Setting Up a Nethack 3.4.3 Server

A guide on how to compile Nethack 3.4.3 and Dgamelaunch, and to configure them to serve game sessions via telnet.
This guide details how to set up a Nethack 3.4.3 server on CentOS 7 or 8. If you are using a different distribution, the required packages may have different names, and the commands used to install them will differ depending on your package manager.

The steps to setup a Nethack 3.4.3 server are as follows:

  1. Installing Requisite Packages
  2. Configuring Nethack for the Chroot Environment
  3. Compiling Nethack
  4. Compiling Dgamelaunch
  5. Creating the Chroot
  6. Configuring Dgamelaunch
  7. Testing Nethack and Dgamelaunch
  8. Setting up the Telnet Server

Here are the directories we will be using in this example:

  • Nethack will be configured before compiling in /home/nethack-temp/
  • The chroot location will be /home/nethack/
  • Nethack will be compiled into /home/nethack-compiled/
  • Dgamelaunch will be compiled into /home/dgamelaunch/

Installing Requisite Packages

The commands that you will run to install all required packages:

yum install gzip make gcc ncurses-libs ncurses-devel byacc flex autoconf automake git sqlite sqlite-devel xinetd telnet-server
dnf config-manager --set-enabled powertools #If CentOS8
yum install flex-devel

Required packages for compiling nethack:

yum install gzip make gcc ncurses-libs ncurses-devel byacc flex

Required packages for compiling dgamelaunch:

yum install git autoconf automake sqlite sqlite-devel
dnf config-manager --set-enabled powertools #If CentOS8
yum install flex-devel

Required packages for the telnet server:

yum install xinetd telnet-server

Downloading Nethack

Download the tarball and unpack it.

mkdir /home/nethack-temp/ && cd /home/nethack-temp/

wget http://downloads.sourceforge.net/project/nethack/nethack/3.4.3/nethack-343-src.tgz

tar -xf nethack-343-src.tgz

cd nethack-3.4.3

Configuring Nethack for the Chroot Environment

  1. Edit src/cmd.c

    2. Change function enter_explore_mode() so users cannot do that; comment it out. Here's what that function will look like when commented out:

    enter_explore_mode()
{
/*  if(!discover && !wizard) {
*           pline("Beware!  From explore mode there will be no return to normal game.");
*           if (yn("Do you want to enter explore mode?") == 'y') {
*                   clear_nhwindow(WIN_MESSAGE);
*                   You("are now in non-scoring explore mode.");
*                   discover = TRUE;
*           }
*           else {
*                   clear_nhwindow(WIN_MESSAGE);
*                   pline("Resuming normal game.");
*               }
*       }
*/      return 0;
}

  2. Edit include/config.h

    3. Change HACKDIR to /nh343 (there is more than one definition of HACKDIR). Here are the lines (with line numbers visible) that need to be changed:

    81:# define HACKDIR "/boot/apps/NetHack"
    113:# define HACKDIR "\\nethack"
    207:# define HACKDIR "/usr/games/lib/nethackdir"

    They should look like this when you are done:

    81:# define HACKDIR "/nh343"
    113:# define HACKDIR "\\nh343"
    207:# define HACKDIR "/nh343"

    Change COMPRESS to /bin/gzip. Comment out these:

    #define COMPRESS "/usr/bin/compress"
    #define COMPRESS_EXTENSION ".Z"

    Uncomment these, and change to /bin/gzip :

    /* #define COMPRESS "/usr/local/bin/gzip" */
    /* #define COMPRESS_EXTENSION ".gz" */

  3. Edit sys/unix/Makefile.top

    • Comment all lines that reference SHELLDIR (We don't need to install the shell script that is usually used to launch NetHack)
    • Change PREFIX to the directory which will contain the compiled NetHack, in this case "/home/nethack-compiled/"
    • Change GAMEDIR to $(PREFIX)/nh343 (This must match HACKDIR in include/config.h)
    • Change VARDIR to $(GAMEDIR)/var (This must match VAR_PLAYGROUND in include/unixconf.h)
    • Change GAMEUID and GAMEGRP to the user and group you will run nethack as; use numbers, not names. In CentOS 8, they are 12 and 20 respectively. In CentOS 7, they are 12 and 100.

  4. Edit sys/unix/Makefile.src

    5. Comment this line:

    WINTTYLIB = -ltermlib

    Uncomment This line:

    #WINTTYLIB = -lncurses

  5. Edit include/unixconf.h

    6. Change VAR_PLAYGROUND to "/nh343/var"

Compiling Nethack

  1. Run the setup script and `make all`.

    2. chmod +x ./sys/unix/setup.sh ./sys/unix/setup.sh make all

    If you get an error involving win/tty/termcap.c, then for this section of win/tty/termcap.c at about line 838:

    #ifndef LINUX extern char *tparm(); #endif

    Change it to instead read as follows, and run `make all` again.

    #ifndef NCURSES_EXPORT extern char *tparm(); #endif

  2. Compile it.

    3. make install

    If you have to go back and fix anything in the makefiles, you should run `make clean` and `./sys/unix/setup.sh` after.

Compiling Dgamelaunch

  1. Download the latest version from GitHub

    2. mkdir /home/dgamelaunch/ && cd /home/dgamelaunch/ git clone https://github.com/paxed/dgamelaunch.git

  2. Run autogen.sh, making sure to use an etc/dgamelaunch.conf file location within the chroot directory you'll be using.

    3. cd dgamelaunch ./autogen.sh --enable-sqlite --enable-shmem --with-config-file=/home/nethack/etc/dgamelaunch.conf

  3. Compile it.

    4. make

Creating the Chroot

  1. Edit these lines in dgl-create-chroot, as follows:

    2. CHROOT "/home/nethack/"
    NETHACKBIN="/home/nethack-compiled/nh343/nethack"
    NH_PLAYGROUND_FIXED="/home/nethack-compiled/nh343"

  2. Setup the Chroot

    3. ./dgl-create-chroot

  3. Create These Files and Directories

    4. cd /home/nethack/
    touch nh343/perm
    mkdir nh343/save
    chmod 777 nh343/save

Configuring Dgamelaunch

Edit these lines in /home/nethack/etc/dgamelaunch.conf as follows:

chroot_path (enter full chroot path) "/home/nethack/" #The backslash at the end matters
maxusers ((set the maximum number of registered users, not simultaneous users)
SERVERID (your server name)
shed_uid (UID of user "games")
shed_gid (GID of group "games")
menu_max_idle_time (uncomment)

Testing Nethack and Dgamelaunch

  1. Make sure that you can run nethack inside the chroot environment.

    2. Try the following as root:

    cd /home/nethack/ chroot ./ nh343/nethack

  2. Make sure that dgamelaunch works.

    3. cd /home/nethack/ ./dgamelaunch

    If you do not get any output when running dgamelaunch, something is wrong.

Setting up the Telnet Server

  1. Install the required packages if you have not already.

    2. yum install xinetd telnet-server

  2. Set up the telnetd to accept incoming connections

    3. If you're using xinetd like we are in this example, you can put this in /etc/xinetd.d/dgl:

    service telnet
{
socket_type     = stream
protocol        = tcp
user            = root
wait            = no
server          = /usr/sbin/in.telnetd
server_args     = -h -L /home/nethack/dgamelaunch
rlimit_cpu      = 120
}

  3. Start the telnet server

    4. service xinetd start chkconfig xinetd on

Testing the Telnet Server

Try connecting locally using 'telnet 127.0.0.1'.
If you get an immediate "connection closed by foreign host", then something is probably wrong with dgamelaunch. A common issue is that the dgamelaunch config file was not specified correctly, and dgamelaunch is looking for it in /etc/dgamelaunch.conf and not in the chroot.

Customizing the Dgamelaunch Menus

  • Edit dgl-banner
  • Edit dgl_menu_*

Cleaning Up

/home/nethack-temp/ and /home/nethack-compiled/ can be removed if you don't need them.

External Links and References Used to Compile This Guide