ATTACH(5) ATTACH(5)
NAME
attach, session, nop - messages to initiate activity
SYNOPSIS
Tnop tag[2]
Rnop tag[2]
Tsession tag[2]
Rsession tag[2]
Tattach tag[2] fid[2] uid[28] aname[28] auth[28]
Rattach tag[2] fid[2] qid[8]
DESCRIPTION
The nop request does nothing overt but may be used to syn-
chronize the channel between two service hosts initially.
The session request is used to initialize a connection
between a client and a server. All outstanding I/O on the
connection is aborted. The set of messages between session
requests is called a session. Tags and fids must be unique
per session.
The tag should be NOTAG (value 0xFFFF) for a nop or session
message.
The attach message serves as a fresh introduction from a
user on the client machine to a server. The message identi-
fies the user (uid) and may select the file tree to access
(aname). The auth argument contains authorization data
derived from the chal field of an auth message; see auth(5)
and auth(6).
As a result of the attach transaction, the client will have
a connection to the root directory of the desired file tree,
represented by fid. An error is returned if fid is already
in use. The server's idea of the root of the file tree is
represented by the returned qid.
ENTRY POINTS
An attach transaction will be generated for kernel devices
(see intro(3)) when a system call evaluates a file name
beginning with `#'. Pipe(2) generates an attach on the ker-
nel device pipe(3). Mount (see bind(2)) generates auth and
attach messages to the remote file server. When the kernel
boots, an attach is made to the root device, root(3), and
then an auth and an attach are made to the requested file
server machine.
SEE ALSO
Page 1 Plan 9 (printed 12/21/24)
ATTACH(5) ATTACH(5)
auth(5), auth(6)
Page 2 Plan 9 (printed 12/21/24)