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: src/usr.sbin/rmt/rmt.8,v 1.5.2.5 2003/03/11 22:31:32 trhodes Exp $ 34.\" $DragonFly: src/usr.sbin/rmt/rmt.8,v 1.4 2006/04/17 18:01:38 swildner Exp $ 35.\" 36.Dd June 1, 1994 37.Dt RMT 8 38.Os 39.Sh NAME 40.Nm rmt 41.Nd remote magtape protocol module 42.Sh SYNOPSIS 43.Nm 44.Sh DESCRIPTION 45The 46.Nm 47utility is used by the remote dump and restore programs 48in manipulating a magnetic tape drive through an interprocess 49communication connection. It is normally started up with an 50.Xr rexec 3 51or 52.Xr rcmd 3 53call. 54.Pp 55The 56.Nm 57utility accepts requests specific to the manipulation of 58magnetic tapes, performs the commands, then responds with 59a status indication. All responses are in 60.Tn ASCII 61and in 62one of two forms. 63Successful commands have responses of: 64.Bd -ragged -offset indent 65.Sm off 66.Sy A Ar number No \en 67.Sm on 68.Ed 69.Pp 70.Ar Number 71is an 72.Tn ASCII 73representation of a decimal number. 74Unsuccessful commands are responded to with: 75.Bd -ragged -offset indent 76.Sm off 77.Xo Sy E Ar error-number 78.No \en Ar error-message 79.No \en 80.Xc 81.Sm on 82.Ed 83.Pp 84.Ar Error-number 85is one of the possible error 86numbers described in 87.Xr intro 2 88and 89.Ar error-message 90is the corresponding error string as printed 91from a call to 92.Xr perror 3 . 93The protocol is comprised of the 94following commands, which are sent as indicated - no spaces are supplied 95between the command and its arguments, or between its arguments, and 96.Ql \en 97indicates that a newline should be supplied: 98.Bl -tag -width Ds 99.Sm off 100.It Xo Sy \&O Ar device 101.No \en Ar mode No \en 102.Xc 103.Sm on 104Open the specified 105.Ar device 106using the indicated 107.Ar mode . 108.Ar Device 109is a full pathname and 110.Ar mode 111is an 112.Tn ASCII 113representation of a decimal 114number suitable for passing to 115.Xr open 2 . 116If a device had already been opened, it is 117closed before a new open is performed. 118.Sm off 119.It Xo Sy C Ar device No \en 120.Xc 121.Sm on 122Close the currently open device. The 123.Ar device 124specified is ignored. 125.Sm off 126.It Xo Sy L 127.Ar whence No \en 128.Ar offset No \en 129.Xc 130.Sm on 131Perform an 132.Xr lseek 2 133operation using the specified parameters. 134The response value is that returned from the 135.Xr lseek 2 136call. 137.Sm off 138.It Sy W Ar count No \en 139.Sm on 140Write data onto the open device. 141The 142.Nm 143utility reads 144.Ar count 145bytes from the connection, aborting if 146a premature end-of-file is encountered. 147The response value is that returned from 148the 149.Xr write 2 150call. 151.Sm off 152.It Sy R Ar count No \en 153.Sm on 154Read 155.Ar count 156bytes of data from the open device. 157If 158.Ar count 159exceeds the size of the data buffer (10 kilobytes), it is 160truncated to the data buffer size. 161The 162.Nm 163utility then performs the requested 164.Xr read 2 165and responds with 166.Sm off 167.Sy A Ar count-read No \en 168.Sm on 169if the read was 170successful; otherwise an error in the 171standard format is returned. If the read 172was successful, the data read is then sent. 173.Sm off 174.It Xo Sy I Ar operation 175.No \en Ar count No \en 176.Xc 177.Sm on 178Perform a 179.Dv MTIOCOP 180.Xr ioctl 2 181command using the specified parameters. 182The parameters are interpreted as the 183.Tn ASCII 184representations of the decimal values 185to place in the 186.Ar mt_op 187and 188.Ar mt_count 189fields of the structure used in the 190.Xr ioctl 2 191call. The return value is the 192.Ar count 193parameter when the operation is successful. 194.It Sy S 195Return the status of the open device, as 196obtained with a 197.Dv MTIOCGET 198.Xr ioctl 2 199call. If the operation was successful, 200an ``ack'' is sent with the size of the 201status buffer, then the status buffer is 202sent (in binary). 203.El 204.Pp 205Any other command causes 206.Nm 207to exit. 208.Sh DIAGNOSTICS 209All responses are of the form described above. 210.Sh SEE ALSO 211.Xr rcmd 3 , 212.Xr rexec 3 , 213.Xr mtio 4 , 214.Xr rdump 8 , 215.Xr rrestore 8 216.Sh HISTORY 217The 218.Nm 219utility appeared in 220.Bx 4.2 . 221.Sh BUGS 222People should be discouraged from using this for a remote 223file access protocol. 224