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Annotation of lucent/sys/man/3/mnt, revision 1.1.1.1

1.1       root        1: .TH MNT 3 
                      2: .SH NAME
                      3: mnt \- attach to 9P servers
                      4: .SH SYNOPSIS
                      5: .nf
                      6: .B #M
                      7: .fi
                      8: .SH DESCRIPTION
                      9: The
                     10: .I mount driver
                     11: is used by the
                     12: .B mount
                     13: system call
                     14: (but not
                     15: .BR bind ;
                     16: see
                     17: .IR bind (2))
                     18: to connect the name space of a process to
                     19: the service provided by a 9P server over a communications channel.
                     20: After the
                     21: .BR mount ,
                     22: system calls involving files in that portion of the name space will
                     23: be converted by the mount driver into the appropriate
                     24: 9P messages to the server.
                     25: .PP
                     26: The
                     27: .I mount
                     28: system call issues
                     29: .I session
                     30: and
                     31: .IR attach (5)
                     32: messages to the server to identify and validate the user of the connection.
                     33: Each distinct user of a connection must mount it separately;
                     34: the mount driver multiplexes the access of the various users and their
                     35: processes to the service.
                     36: .PP
                     37: File-oriented system calls are converted by the kernel into messages in the 9P protocol.
                     38: Within the kernel, 9P is implemented by procedure calls to the
                     39: various kernel device drivers.
                     40: The mount driver translates these procedure calls into remote procedure calls
                     41: to be transmitted as messages over the communication channel to the server.
                     42: Each message is implemented by a write
                     43: of the corresponding protocol message to the server channel
                     44: followed by a read on the server channel to get the reply.
                     45: Errors in the reply message are turned into system call error returns.
                     46: .PP
                     47: A
                     48: .IR read (2)
                     49: or
                     50: .IR write
                     51: system call on a file served by the mount driver
                     52: may be translated
                     53: into more than one
                     54: message,
                     55: since there is a maximum data size for a 9P message.
                     56: The system call
                     57: will return when the specified number of bytes have been transferred
                     58: or a short reply is returned.
                     59: .PP
                     60: The string
                     61: .L #M
                     62: is an illegal file name,
                     63: so this device can only be accessed directly by the kernel.
                     64: .SH "SEE ALSO"
                     65: .IR bind (2)
                     66: .SH SOURCE
                     67: .B /sys/src/9/port/devmnt.c
                     68: .SH BUGS
                     69: When mounting a service through the mount driver,
                     70: that is, when the channel being multiplexed is itself
                     71: a file being served by the mount driver,
                     72: large messages may be broken in two.

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