1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)rmt.8 8.3 (Berkeley) 6/1/94 33.\" $FreeBSD$ 34.\" 35.Dd June 1, 1994 36.Dt RMT 8 37.Os 38.Sh NAME 39.Nm rmt 40.Nd remote magtape protocol module 41.Sh SYNOPSIS 42.Nm 43.Sh DESCRIPTION 44The 45.Nm 46utility is used by the remote dump and restore programs 47in manipulating a magnetic tape drive through an interprocess 48communication connection. It is normally started up with an 49.Xr rexec 3 50or 51.Xr rcmd 3 52call. 53.Pp 54The 55.Nm 56utility accepts requests specific to the manipulation of 57magnetic tapes, performs the commands, then responds with 58a status indication. All responses are in 59.Tn ASCII 60and in 61one of two forms. 62Successful commands have responses of: 63.Bd -ragged -offset indent 64.Sm off 65.Sy A Ar number No \en 66.Sm on 67.Ed 68.Pp 69.Ar Number 70is an 71.Tn ASCII 72representation of a decimal number. 73Unsuccessful commands are responded to with: 74.Bd -ragged -offset indent 75.Sm off 76.Xo Sy E Ar error-number 77.No \en Ar error-message 78.No \en 79.Xc 80.Sm on 81.Ed 82.Pp 83.Ar Error-number 84is one of the possible error 85numbers described in 86.Xr intro 2 87and 88.Ar error-message 89is the corresponding error string as printed 90from a call to 91.Xr perror 3 . 92The protocol is comprised of the 93following commands, which are sent as indicated - no spaces are supplied 94between the command and its arguments, or between its arguments, and 95.Ql \en 96indicates that a newline should be supplied: 97.Bl -tag -width Ds 98.Sm off 99.It Xo Sy \&O Ar device 100.No \en Ar mode No \en 101.Xc 102.Sm on 103Open the specified 104.Ar device 105using the indicated 106.Ar mode . 107.Ar Device 108is a full pathname and 109.Ar mode 110is an 111.Tn ASCII 112representation of a decimal 113number suitable for passing to 114.Xr open 2 . 115If a device had already been opened, it is 116closed before a new open is performed. 117.Sm off 118.It Xo Sy C Ar device No \en 119.Xc 120.Sm on 121Close the currently open device. The 122.Ar device 123specified is ignored. 124.Sm off 125.It Xo Sy L 126.Ar whence No \en 127.Ar offset No \en 128.Xc 129.Sm on 130Perform an 131.Xr lseek 2 132operation using the specified parameters. 133The response value is that returned from the 134.Xr lseek 135call. 136.Sm off 137.It Sy W Ar count No \en 138.Sm on 139Write data onto the open device. 140The 141.Nm 142utility reads 143.Ar count 144bytes from the connection, aborting if 145a premature end-of-file is encountered. 146The response value is that returned from 147the 148.Xr write 2 149call. 150.Sm off 151.It Sy R Ar count No \en 152.Sm on 153Read 154.Ar count 155bytes of data from the open device. 156If 157.Ar count 158exceeds the size of the data buffer (10 kilobytes), it is 159truncated to the data buffer size. 160The 161.Nm 162utility then performs the requested 163.Xr read 2 164and responds with 165.Sm off 166.Sy A Ar count-read No \en 167.Sm on 168if the read was 169successful; otherwise an error in the 170standard format is returned. If the read 171was successful, the data read is then sent. 172.Sm off 173.It Xo Sy I Ar operation 174.No \en Ar count No \en 175.Xc 176.Sm on 177Perform a 178.Dv MTIOCOP 179.Xr ioctl 2 180command using the specified parameters. 181The parameters are interpreted as the 182.Tn ASCII 183representations of the decimal values 184to place in the 185.Ar mt_op 186and 187.Ar mt_count 188fields of the structure used in the 189.Xr ioctl 2 190call. The return value is the 191.Ar count 192parameter when the operation is successful. 193.It Sy S 194Return the status of the open device, as 195obtained with a 196.Dv MTIOCGET 197.Xr ioctl 2 198call. If the operation was successful, 199an ``ack'' is sent with the size of the 200status buffer, then the status buffer is 201sent (in binary). 202.El 203.Pp 204Any other command causes 205.Nm 206to exit. 207.Sh DIAGNOSTICS 208All responses are of the form described above. 209.Sh SEE ALSO 210.Xr rcmd 3 , 211.Xr rexec 3 , 212.Xr mtio 4 , 213.Xr rdump 8 , 214.Xr rrestore 8 215.Sh BUGS 216People should be discouraged from using this for a remote 217file access protocol. 218.Sh HISTORY 219The 220.Nm 221utility appeared in 222.Bx 4.2 . 223