Manual browser: dm(8)

DM(8) System Manager's Manual DM(8)


dmdungeon master


ln -s dm game


dm is a program used to regulate game playing. dm expects to be invoked with the name of a game that a user wishes to play. This is done by creating symbolic links to dm, in the directory /usr/games for all of the regulated games. The actual binaries for these games should be placed in a “hidden” directory, /usr/games/hide, that may only be accessed by the dm program. dm determines if the requested game is available and, if so, runs it. The file /etc/dm.conf controls the conditions under which games may be run.

The file /etc/nogames may be used to “turn off” game playing. If the file exists, no game playing is allowed; the contents of the file will be displayed to any user requesting a game.


configuration file
turns off game playing
directory of ``real'' binaries
game logging file




The dm command appeared in 4.3BSD-Tahoe.


Two issues result from dm running the games setgid “games”. First, all games that allow users to run UNIX commands should carefully set both the real and effective group ids immediately before executing those commands. Probably more important is that dm never be setgid anything but “games” so that compromising a game will result only in the user's ability to play games at will. Secondly, games which previously had no reason to run setgid and which accessed user files may have to be modified.
May 31, 1993 NetBSD 7.0