152 lines
3.2 KiB
Plaintext
152 lines
3.2 KiB
Plaintext
.\" Copyright (c) 1983 Regents of the University of California.
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.\" All rights reserved. The Berkeley software License Agreement
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.\" specifies the terms and conditions for redistribution.
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.\"
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.\" @(#)rmt.8c 6.1 (Berkeley) 4/27/85
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.\"
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.TH RMT 8C "April 27, 1985"
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.UC 5
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.SH NAME
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rmt \- remote magtape protocol module
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.SH SYNOPSIS
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.B /etc/rmt
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.SH DESCRIPTION
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.I Rmt
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is a program used by the remote dump and restore programs
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in manipulating a magnetic tape drive through an interprocess
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communication connection.
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.I Rmt
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is normally started up with an
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.IR rexec (3X)
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or
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.IR rcmd (3X)
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call.
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.PP
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The
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.I rmt
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program accepts requests specific to the manipulation of
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magnetic tapes, performs the commands, then responds with
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a status indication. All responses are in ASCII and in
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one of two forms.
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Successful commands have responses of
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.PP
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.ti +0.5i
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\fBA\fInumber\fR\en
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.PP
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where
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.I number
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is an ASCII representation of a decimal number.
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Unsuccessful commands are responded to with
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.PP
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.ti +0.5i
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\fBE\fIerror-number\fR\en\fIerror-message\fR\en,
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.PP
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where
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.I error-number
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is one of the possible error
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numbers described in
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.IR intro (2)
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and
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.I error-message
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is the corresponding error string as printed
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from a call to
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.IR perror (3).
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The protocol is comprised of the
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following commands (a space is present between each token).
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.TP 15
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.B O device mode
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Open the specified
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.I device
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using the indicated
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.IR mode .
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.I Device
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is a full pathname and
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.I mode
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is an ASCII representation of a decimal
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number suitable for passing to
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.IR open (2).
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If a device had already been opened, it is
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closed before a new open is performed.
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.TP 15
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.B C device
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Close the currently open device. The
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.I device
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specified is ignored.
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.TP 15
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.B L whence offset
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Perform an
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.IR lseek (2)
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operation using the specified parameters.
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The response value is that returned from the
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.I lseek
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call.
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.TP 15
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.B W count
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Write data onto the open device.
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.I Rmt
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reads
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.I count
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bytes from the connection, aborting if
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a premature end-of-file is encountered.
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The response value is that returned from
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the
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.IR write (2)
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call.
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.TP 15
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.B R count
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Read
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.I count
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bytes of data from the open device.
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If
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.I count
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exceeds the size of the data buffer (10 kilobytes), it is
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truncated to the data buffer size.
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.I Rmt
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then performs the requested
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.IR read (2)
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and responds with
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\fBA\fIcount-read\fR\en if the read was
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successful; otherwise an error in the
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standard format is returned. If the read
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was successful, the data read is then sent.
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.TP 15
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.B I operation count
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Perform a MTIOCOP
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.IR ioctl (2)
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command using the specified parameters.
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The parameters are interpreted as the
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ASCII representations of the decimal values
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to place in the
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.I mt_op
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and
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.I mt_count
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fields of the structure used in the
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.I ioctl
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call. The return value is the
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.I count
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parameter when the operation is successful.
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.TP 15
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.B S
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Return the status of the open device, as
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obtained with a MTIOCGET
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.I ioctl
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call. If the operation was successful,
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an ``ack'' is sent with the size of the
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status buffer, then the status buffer is
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sent (in binary).
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.PP
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Any other command causes
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.I rmt
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to exit.
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.SH DIAGNOSTICS
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All responses are of the form described above.
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.SH "SEE ALSO"
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rcmd(3X),
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rexec(3X),
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mtio(4),
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rdump(8C),
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rrestore(8C)
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.SH BUGS
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People tempted to use this for a remote file access protocol
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are discouraged.
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