GAMESRV(4) GAMESRV(4)
NAME
gamesrv - game server
SYNOPSIS
games/gamesrv [ -l ] [ -a alg ]... [ -A ] [ addr|mntpoint ]
mntpoint/players
mntpoint/new
mntpoint/n
DESCRIPTION
Gamesrv serves a file system that allows clients to interact
through various types of game engine. Usually, it operates
in network mode: it listens for incoming connections on addr
(default tcp!*!3242), authenticates them, and serves files
to them. If the -A option is given, no authentication takes
place, otherwise each alg gives an additional possible
encryption or digest algorithm to use on the connection (see
ssl(3)). If no alg is specified, none is assumed. The -l
option causes the game server to be mounted locally on
mntpoint - this can be useful for single player games, or
debugging.
Once the name-space served by gamesrv is mounted, it serves
the following files. All identifiers referred to below are
small integers, expressed as decimal ASCII strings.
players
Reading this file provides updates on players arriving
and leaving, games being created and destroyed, and
chat messages outside the scope of any game. Reads
will block until something of interest happens. Each
update holds space separated tokens and is terminated
with a newline. A read will return as many updates as
will fit into the read buffer. Update messages are as
follows:
clientid clientid name
Identifies the name, name, and the client identi-
fier, clientid, of the client reading the players
file.
join clientid name
A client has authenticated as name, and has been
allocated identifier clientid.
leave clientid
The client identified by clientid has terminated
connection with the server.
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GAMESRV(4) GAMESRV(4)
gametype clienttype name
The server announces the availability of a game
named name on the server. The game requires a
client of type clienttype to display the game.
creategame gameid name clienttype
An instance of a game named name has been created;
it needs a client of type clienttype, and has been
given identifier gameid.
deletegame gameid
The game identified by gameid has been deleted.
joingame gameid clientid playerid name
Client clientid (named name) has joined game
gameid , and is allocated player id playerid in
the game.
leavegame gameid playerid name
Player playerid (named name) has left gameid.
chat clientid msg
Client clientid has sent the chat message msg.
Writing to the players file causes a chat message to be
sent to all other clients reading the players file. All
but the first line of the write request is ignored.
new Opening new prepares to create a new game. The only
message that can be written to a newly opened game is
``create name'', to request a new game named name. The
write request draws an error if gamesrv fails to find
and load the requisite game engine. If the write suc-
ceeds, the game is created, and game updates can be
read in the same manner as from the players file. The
update messages are as follows:
playerid clientid playerid name
Identifies the player identifier, playerid, and
name, name, of the reader.
create objid parentid visibility objtype
Create an object, identified by objid, at the end
of parentid's children (parentid is -1 for the
root object). Visibility is the visibility set of
the object (see gamesrv(2)), and objtype is its
type.
tx srcid dstid start end index
Transfer objects from srcid to dstid. Take the
objects from the range [start, end) in the chil-
dren of srcid, and insert them just before index
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GAMESRV(4) GAMESRV(4)
in dstid. Note that when objects are transferred
to an object that conceals its children, and the
object is itself visible, the objects will first
be transferred to the destination and then
deleted; objects transferred out of such an object
will first be created and then transferred to
their destination. This enables a client to main-
tain some knowledge of where an object has been
transferred to, even if the object is no longer
visible.
del parentid start end
Delete the range [start, end) of children from the
object identified by parentid. Gamesrv guarantees
that those objects will themselves not have any
children.
set objid attr val
Set the attribute named attr on object objid to
val.
vis objid visibility
The visibility of object objid has changed to
visibility.
action
Game engines can generate arbitrary messages of
their own devising; such messages are specific to
particular client types.
Note that a given client does not have to interpret all
the above messages - different client types have their
own conventions. The card client type uses most of the
above functionality, for example, whereas a client for
the chat engine listed in gamesrv(2) can get away with
interpreting only one message, the custom action chat.
Writes to the opened game file are interpreted as game
actions by the game that has been loaded, and acted on
accordingly. Invalid actions will draw a write error.
n Once a game has been created, it appears as a numbered
file, corresponding to the gameid of the game in ques-
tion. Opening this file joins the game; reads and
writes work as for the new file, above. A single
client cannot join a particular game more than once.
A zero-length write to any file causes any reads of that
file from the same file descriptor to yield EOF (no bytes).
This is necessary to force a hangup under systems such as
Windows, where it is not possible to interrupt a kproc
blocked on a network read.
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GAMESRV(4) GAMESRV(4)
EXAMPLE
The simplest client!
mount tcp!somehost.com!3242 /n/remote
{
echo create chat >[1=0]
cat &
cat < /dev/cons >[1=0]
} <> /n/remote/new
SOURCE
/appl/cmd/games/gamesrv.b
SEE ALSO
gamesrv(2)
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