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 8.2 (Berkeley) 12/11/93 33.\" 34.Dd December 11, 1993 35.Dt RMT 8 36.Os BSD 4.2 37.Sh NAME 38.Nm rmt 39.Nd remote magtape protocol module 40.Sh SYNOPSIS 41.Nm rmt 42.Sh DESCRIPTION 43.Nm Rmt 44is a program used by the remote dump and restore programs 45in manipulating a magnetic tape drive through an interprocess 46communication connection. 47.Nm Rmt 48is normally started up with an 49.Xr rexec 3 50or 51.Xr rcmd 3 52call. 53.Pp 54The 55.Nm rmt 56program 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 -filled -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 -filled -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 102Open the specified 103.Ar device 104using the indicated 105.Ar mode . 106.Ar Device 107is a full pathname and 108.Ar mode 109is an 110.Tn ASCII 111representation of a decimal 112number suitable for passing to 113.Xr open 2 . 114If a device had already been opened, it is 115closed before a new open is performed. 116.It Xo Sy C Ar device No \en 117.Xc 118Close the currently open device. The 119.Ar device 120specified is ignored. 121.It Xo Sy L 122.Ar whence No \en 123.Ar offset No \en 124.Xc 125.Sm on 126Perform an 127.Xr lseek 2 128operation using the specified parameters. 129The response value is that returned from the 130.Xr lseek 131call. 132.Sm off 133.It Sy W Ar count No \en 134.Sm on 135Write data onto the open device. 136.Nm Rmt 137reads 138.Ar count 139bytes from the connection, aborting if 140a premature end-of-file is encountered. 141The response value is that returned from 142the 143.Xr write 2 144call. 145.Sm off 146.It Sy R Ar count No \en 147.Sm on 148Read 149.Ar count 150bytes of data from the open device. 151If 152.Ar count 153exceeds the size of the data buffer (10 kilobytes), it is 154truncated to the data buffer size. 155.Nm rmt 156then performs the requested 157.Xr read 2 158and responds with 159.Sm off 160.Sy A Ar count-read No \en 161.Sm on 162if the read was 163successful; otherwise an error in the 164standard format is returned. If the read 165was successful, the data read is then sent. 166.Sm off 167.It Xo Sy I Ar operation 168.No \en Ar count No \en 169.Xc 170.Sm on 171Perform a 172.Dv MTIOCOP 173.Xr ioctl 2 174command using the specified parameters. 175The parameters are interpreted as the 176.Tn ASCII 177representations of the decimal values 178to place in the 179.Ar mt_op 180and 181.Ar mt_count 182fields of the structure used in the 183.Xr ioctl 184call. The return value is the 185.Ar count 186parameter when the operation is successful. 187.It Sy S 188Return the status of the open device, as 189obtained with a 190.Dv MTIOCGET 191.Xr ioctl 192call. If the operation was successful, 193an ``ack'' is sent with the size of the 194status buffer, then the status buffer is 195sent (in binary). 196.El 197.Sm on 198.Pp 199Any other command causes 200.Nm rmt 201to exit. 202.Sh DIAGNOSTICS 203All responses are of the form described above. 204.Sh SEE ALSO 205.Xr rcmd 3 , 206.Xr rexec 3 , 207.Xr mtio 4 , 208.Xr rdump 8 , 209.Xr rrestore 8 210.Sh BUGS 211People should be discouraged from using this for a remote 212file access protocol. 213.Sh HISTORY 214The 215.Nm 216command appeared in 217.Bx 4.2 . 218