rmt
remote magtape protocol module
see also :
tar - cpio - mt - rsh
Synopsis
rmt
add an example, a script, a trick and tips
examples
source
cd $NTK_REPOSITORY
for rmt in freaknet.org
tamarindo.freaknet.org
do
rsync -auv -P $packdir.tar.bz2
$rmt:netsukuku/files/
rsync -auPv $STATIC_PACKAGES $rmt:netsukuku/files/
done
description
Rmt is a program used by
tar, cpio, mt, and the remote dump and restore programs in
manipulating a magnetic tape drive through an interprocess
communication connection. Rmt is normally started up
with an rexec(3) or rcmd(3) call or the rsh(1) command.
The rmt
program accepts requests specific to the manipulation of
magnetic tapes, performs the commands, then responds with a
status indication. All responses are in ASCII and in one of
two forms. Successful commands have responses of:
Anumber\n
Number is
an ASCII representation of a decimal number. Unsuccessful
commands are responded to with:
Eerror-number\nerror-message\n
Error-number
is one of the possible error numbers described in intro(2)
and error-message is the corresponding error string
as printed from a call to perror(3). The protocol is
comprised of the following commands, which are sent as
indicated - no spaces are supplied between the command and
its arguments, or between its arguments, and
’\n’ indicates that a newline should be
supplied:
Odevice\nmode\n
Open the specified
deviceusing the indicated mode.Deviceis
a full pathname and modeis an ASCIIrepresentation of
a decimal number suitable for passing to open(2).If a device
had already been opened, it is closed before a new open is
performed.
Cdevice\n
Close the currently open
device. The devicespecified is ignored.
Loffset\nwhence\n
Perform an lseek(2) operation
using the specified parameters. The response value is that
returned from the lseek call.
Wcount\n
Write data onto the open
device. Rmt reads count bytes from the
connection, aborting if a premature end-of-file is
encountered. The response value is that returned from the
write(2) call.
Rcount\n
Read count bytes of data
from the open device. If count exceeds the size of
the data buffer (10 kilobytes), it is truncated to the data
buffer size. rmt then performs the requested read(2)
and responds with Acount-read\n if the read
was successful; otherwise an error in the standard format is
returned. If the read was successful, the data read is then
sent.
Ioperation\ncount\n
Perform a MTIOCOP ioctl(2)
command using the specified parameters. The parameters are
interpreted as the ASCII representations of the decimal
values to place in the mt_op and mt_count
fields of the structure used in the ioctl call. The return
value is the count parameter when the operation is
successful.
S
Return the
status of the open device, as obtained with a MTIOCGET ioctl
call. If the operation was successful, an
’’ack’’ is sent with the size of the
status buffer, then the status buffer is sent (in
binary).
Any other
command causes rmt to exit.
diagnostics
All responses are of the form described above.
bugs
People should be discouraged
from using this for a remote file access protocol.
history
The rmt command appeared
in 4.2BSD.
4.2 Berkeley
Distribution December 11, 1993 4.2 Berkeley
Distribution
see also
tar , cpio , mt , rsh ,
rcmd, rexec, mtio, rdump, rrestore