3 plumber \- file system for interprocess messaging
13 is a user-level file server that receives, examines, rewrites, and dispatches
15 messages between programs.
16 Its behavior is programmed by a
19 .BR $HOME/lib/plumbing )
23 Its services are posted via
34 for dispatching messages to applications.
40 to deliver messages to the
44 to receive them from the corresponding port.
50 command cause a message to be sent to
53 in turn reads from, by convention,
55 to receive messages about files to open.
57 A copy of each message is sent to each client that has the corresponding port open.
58 If none has it open, and the rule has a
64 rule, that rule is applied.
68 rule causes the specified command to be run
69 and the message to be held for delivery when the port is opened.
73 rule runs the command but discards the message.
78 is specified and the port is not open,
79 the message is discarded and a write error is returned to the sender.
81 The set of output ports is determined dynamically by the
82 specification in the plumbing rules file: a port is created for each unique
88 The set of rules currently active may be examined by reading the file
90 appending to this file adds new rules to the set, while
91 creating it (opening it with
94 Thus the rule set may be edited dynamically with a traditional text editor.
95 However, ports are never deleted dynamically; if a new set of rules does not
96 include a port that was defined in earlier rules, that port will still exist (although
97 no new messages will be delivered there).
99 .TF $HOME/lib/plumbing
101 .B $HOME/lib/plumbing
105 directory to search for files in
120 .\" file name space is fixed, so it is difficult to plumb
121 .\" messages that involve files in newly mounted services.