186 lines
4.7 KiB
Groff
186 lines
4.7 KiB
Groff
.\" $NetBSD: rmtops.3,v 1.9 2004/06/10 13:58:47 uebayasi Exp $
|
|
.\"
|
|
.Dd October 16, 2001
|
|
.Os
|
|
.Dt RMTOPS 3
|
|
.Sh NAME
|
|
.Nm rmtops
|
|
.Nd access tape drives on remote machines
|
|
.Sh LIBRARY
|
|
Remote Magnetic Tape Library (librmt, -lrmt)
|
|
.Sh SYNOPSIS
|
|
.In rmt.h
|
|
.In sys/stat.h
|
|
.Ft int
|
|
.Fn isrmt "int fd"
|
|
.Ft int
|
|
.Fn rmtaccess "char *file" "int mode"
|
|
.Ft int
|
|
.Fn rmtclose "int fd"
|
|
.Ft int
|
|
.Fn rmtcreat "char *file" "int mode"
|
|
.Ft int
|
|
.Fn rmtdup "int fd"
|
|
.Ft int
|
|
.Fn rmtfcntl "int fd" "int cmd" "int arg"
|
|
.Ft int
|
|
.Fn rmtfstat "int fd" "struct stat *buf"
|
|
.Ft int
|
|
.Fn rmtioctl "int fd" "int request" "char *argp"
|
|
.Ft int
|
|
.Fn rmtisatty "int fd"
|
|
.Ft long
|
|
.Fn rmtlseek "int fd" "long offset" "int whence"
|
|
.Ft int
|
|
.Fn rmtlstat "char *file" "struct stat *buf"
|
|
.Ft int
|
|
.Fn rmtopen "char *file" "int flags" "int mode"
|
|
.Ft int
|
|
.Fn rmtread "int fd" "char *buf" "int nbytes"
|
|
.Ft int
|
|
.Fn rmtstat "char *file" "struct stat *buf"
|
|
.Ft int
|
|
.Fn rmtwrite "int fd" "char *buf" "int nbytes"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm
|
|
library provides a simple means of transparently accessing tape drives
|
|
on remote machines via
|
|
.Xr rsh 1
|
|
and
|
|
.Xr rmt 8 .
|
|
These routines are used like their corresponding system calls, but
|
|
allow the user to open up a tape drive on a remote system on which he
|
|
or she has an account and the appropriate remote permissions.
|
|
.Pp
|
|
A remote tape drive file name has the form
|
|
.sp
|
|
[user@]hostname:/dev/???
|
|
.sp
|
|
where
|
|
.Em system
|
|
is the remote system,
|
|
.Em /dev/???
|
|
is the particular drive on the remote system (raw, blocked, rewinding,
|
|
non-rewinding, etc.), and the optional
|
|
.Em user
|
|
is the login name to be used on the remote system, if different from
|
|
the current user's login name.
|
|
.\" .Pp
|
|
.\" The library source code may be optionally compiled to recognize the
|
|
.\" old
|
|
.\" .Bx 4.2 ,
|
|
.\" remote syntax
|
|
.\" .sp
|
|
.\" hostname[.user]:/dev/???
|
|
.\" .sp
|
|
.\" By default, only the first form (introduced in
|
|
.\" .Bx 4.3 )
|
|
.\" is recognized.
|
|
.Pp
|
|
For transparency, the user should include the file
|
|
.Pa \*[Lt]rmt.h\*[Gt] ,
|
|
which has the following defines in it:
|
|
.Pp
|
|
.Bd -literal
|
|
#define access rmtaccess
|
|
#define close rmtclose
|
|
#define creat rmtcreat
|
|
#define dup rmtdup
|
|
#define fcntl rmtfcntl
|
|
#define fstat rmtfstat
|
|
#define ioctl rmtioctl
|
|
#define isatty rmtisatty
|
|
#define lseek rmtlseek
|
|
#define lstat rmtlstat
|
|
#define open rmtopen
|
|
#define read rmtread
|
|
#define stat rmtstat
|
|
#define write rmtwrite
|
|
.Ed
|
|
.Pp
|
|
This allows the programmer to use
|
|
.Xr open 2 ,
|
|
.Xr close 2 ,
|
|
.Xr read 2 ,
|
|
.Xr write 2 ,
|
|
etc. in their normal fashion, with the
|
|
.Nm
|
|
routines taking care of differentiating between local and remote files.
|
|
This file should be included
|
|
.Em before
|
|
including the file
|
|
.Pa \*[Lt]sys/stat.h\*[Gt] ,
|
|
since it redefines the identifier ``stat'' which is used to declare
|
|
objects of type
|
|
.Em "struct stat" .
|
|
.Pp
|
|
The routines differentiate between local and remote file descriptors
|
|
by adding a bias (currently 128) to the file descriptor of the pipe.
|
|
The programmer, if he or she must know if a file is remote, should use
|
|
.Fn isrmt .
|
|
.Sh ENVIRONMENT
|
|
The RCMD_CMD environment variable can be set to the name or pathname
|
|
of a program to use, instead of
|
|
.Pa /usr/bin/rsh ,
|
|
and must have the same calling conventions as
|
|
.Xr rsh 1 .
|
|
.Sh FILES
|
|
.Bl -tag -width /usr/lib/librmt.a -compact
|
|
.It Pa /usr/lib/librmt.a
|
|
remote tape library
|
|
.El
|
|
.Sh DIAGNOSTICS
|
|
Several of these routines will return \-1 and set
|
|
.Va errno
|
|
to EOPNOTSUPP, if they are given a remote file name or a file descriptor
|
|
on an open remote file (e.g.,
|
|
.Fn rmtdup ) .
|
|
.Sh SEE ALSO
|
|
.Xr rcp 1 ,
|
|
.Xr rsh 1 ,
|
|
.Xr rmt 8
|
|
.Pp
|
|
And the appropriate system calls in section 2.
|
|
.\" .Sh CONFIGURATION OPTIONS
|
|
.\" The library may be compiled to allow the use of
|
|
.\" .Bx 4.2 -style
|
|
.\" remote file names. This is not recommended.
|
|
.\" .Pp
|
|
.\" By default, the library opens two pipes to
|
|
.\" .Xr rsh 1 .
|
|
.\" It may optionally be compiled to use
|
|
.\" .Xr rexec 3 ,
|
|
.\" instead. Doing so requires the use of a
|
|
.\" .Em .netrc
|
|
.\" file in the user's home directory, or that the application designer be
|
|
.\" willing to have
|
|
.\" .Xr rexec 3
|
|
.\" prompt the user for a login name and password on the remote host.
|
|
.Sh AUTHORS
|
|
Jeff Lee wrote the original routines for accessing tape drives via
|
|
.Xr rmt 8 .
|
|
.Pp
|
|
Fred Fish redid them into a general purpose library.
|
|
.Pp
|
|
Arnold Robbins added the ability to specify a user name on the remote
|
|
system, the
|
|
.Pa \*[Lt]rmt.h\*[Gt]
|
|
include file, this man page, cleaned up the library a little, and made
|
|
the appropriate changes for
|
|
.Bx 4.3 .
|
|
.Pp
|
|
Dan Kegel contributed the code to use the
|
|
.Xr rexec 3
|
|
library routine.
|
|
.Sh BUGS
|
|
There is no way to use remote tape drives with
|
|
.Xr stdio 3 ,
|
|
short of recompiling it entirely to use these routines.
|
|
.Pp
|
|
The
|
|
.Xr rmt 8
|
|
protocol is not very capable.
|
|
In particular, it relies on TCP/IP sockets for error
|
|
free transmission, and does no data validation of its own.
|