NAME¶
hose - the client end of a BSD network pipe
netpipes 4.2
SYNOPSIS¶
hose hostname port (
--in|
--out|
--err|
--fd
n|
--slave|
--netslave|
--netslave1|
--netslave2) [
--verbose] [
--unix] [
--localport port] [
--localhost addr] [
--retry n] [
--delay n] [
--shutdown
[r|w][a] ] [
--noreuseaddr] [
-[
i][
o][
e][
#3[,
4[,
5...]]][
s][
v][
u]]
[
-p local-port] [
-h local-host]
command
args
DESCRIPTION¶
hose attempts to provide the functionality of pipes over the network. It
behaves as the client end of a server-client connection. When used with
faucet(1) it can function as a replacement for
tar -cf - . | rsh other "cd destdir; tar -xf -"
faucet and
hose are especially useful when you don't have easy
non-interactive access to the destination machine.
OPTIONS¶
hose creates a BSD socket and, if the
--localport option is used,
binds it to the port number (or service name) specified immediately
afterwards. If
--localhost is also specified then its argument is a
local address to bind to. (
--localhost is only useful on machines with
multiple IP addresses.)
hose then tries to connect to the foreign machine
hostname with
foreign port
port.
If successful
hose redirects the socket to stdin, stdout, stderr, and/or
arbitrary file descriptors according to the
--in --out --err --fd
n flags.
hose also automagically shuts down the unused half
of the connection if only
--in is specified or if only
--out
and/or
--err are specified. See the
--shutdown option for more
information.
hose then exec(2)s a
command with
args.
However, the
--slave flag turns
hose into a primitive sort of
telnet. The
command is ignored. Instead,
hose goes into a loop
where it copies bytes from stdin to the socket, and bytes from the socket to
stdout. This is actually more useful than telnet because telnet tries to
perform interpretation on the byte stream and generally gets in your way.
hose just passes bytes without mucking with them.
The
--netslave* options are variants on the
--slave theme. Whereas
--slave will continue to forward data in one direction even after the
other has encountered EOF,
--netslave variants are more aggressive in
closing the entire socket. Before closing the socket, it attempts to flush any
data already in its own buffer.
--slave performs the
shutdown(2) system
call when it encounters EOF on one direction, but the
--netslave
variants don't because some network daemons are confused by it.
--netslave closes down the connection when it encounters EOF in either
direction.
--netslave1 closes down the connection when it encounters EOF while
reading stdin. Any data unread on the socket will be ignored. If it merely
encounters EOF on the socket, it will continue to read from stdin.
--netslave2 closes down the connection when it encounters EOF while
reading from the socket. Any data unread on stdin will be ignored. If it
merely encounters EOF on stdin, it will continue to read from the socket. This
mode can be useful with some web servers.
The
--verbose flag specifies that
hose should print information
about the host it connects to. This information includes the numeric host
address, host names, and foreign port numbers.
The
--unix flag specifies that the
port is not an internet port
number or service name, but instead it is a filename for a UNIX domain socket.
This option may be simulated by using
-unix- as the host name to
connect to, or by renaming the
hose program to
uhose.
--retry n allows the user to specify that
hose should retry
the
connect(2) call for
n times (or forever if
n is negative).
--delay n specifies how many seconds to delay between tries.
--shutdown is used to control two behaviors. The first set is controlled
by the `r' and `w' flags. If the `r' is present, then
hose will close
half the connection to make it a read-only socket. If the child tries to
write, it will fail. If the remote connection tries to read, it will percieve
the socket as closed. If instead the `w' is present, then
hose will
close the other half of the connection to make it a write-only socket. If the
child tries to read, it will percieve the socket as closed. If the remote
connection tries to write, it will fail. The default behavior is to leave both
halves open, however the shutdown of half of the connection is automagically
done by certain combinations of the
--in,
--out, and
--err flags. To suppress their automagic behavior you can use
(respectively) --fd 0, --fd 1, and --fd 2.
The other behavior is controlled by the `a' flag. If the `a' flag is present
then
hose will
fork(2) before execcing the
command and when the
child exits it will perform a
shutdown(2) with how=2. This closes both halves
of the connection. This option is not necessary for most applications since
the closing of the file descriptors is detected by the remote process, but
some less sophisticated network devices (such as printers) require a
shutdown(2) for proper operation. To make things perfectly clear, the list of
acceptable arguments to the
--shutdown option are `r', `w', `ra', `wa',
`a'.
By default,
hose performs a
which prevents the ``Address in use'' problem that ``plagued'' netpipes versions
4.0 and earlier.
--noreuseaddr tells
hose to skip that system
call, and revert to pre-4.1 behavior. Without this call, the port is not
always available for immediate reuse after the
hose exits.
SHORT FLAGS¶
To reduce the typing requirements for arguments (and to pay homage to the
age-old tradition of UNIX cryptotaxonomy) I have added some short forms of the
flags. Here is a correspondence chart:
Short |
Long |
i |
in |
o |
out |
e |
err |
#n |
fdn |
s |
slave |
v |
verbose |
q |
quiet |
u |
unix |
p |
localport |
h |
localhost |
See
faucet(1) for a more detailed discussion of short flags. Their behavior
should be unsurprising. The flags that require separate arguments follow in
the tradition of
tar(1).
EXAMPLES¶
This will connect to port 3000 on the machine reef and connect the socket to the
stdin of a tar command.
example$ hose reef 3000 --in tar -xf - .
The command actually exec(2)ed by the
hose program is
tar -xf - .
The
--in option means that the input of the child process will have been
redirected into the socket connected to reef.
This connects to a UNIX domain socket in the current directory
example$ hose --unix- u-socket --in sh -c \
"unfunky.perl.script | dd of=sample.pgm"
The socket provides input to the sh command.
SEE ALSO¶
netpipes (1), faucet (1), sockdown (1), getpeername (1), socket (2), bind (2),
connect (2), shutdown (2), services (5), gethostbyaddr (3)
NOTES¶
Doubtless there are bugs in this program, especially in the unix domain socket
portions. I welcome problem reports and would like to make these programs as
"clean" (no leftover files, sockets) as possible.
4.0 made the full-word arguments use -- like many GNU programs. They are still
available with a single - for backward-compatibility.
3.1 added the single-character flags.
Release 2.3 added support for multi-homed hosts: hosts with multiple internet
numbers (such as gateways). Before this faucet assumed that the first internet
number that gethostbyname returned was the only one.
--foreignport
authentication was weakened by this inadequacy so I beefed up the algorithms.
--foreignport will accept a connection from any of the internet numbers
associated with the host name.
CREDITS¶
Thanks to Steve Clift <clift@ml.csiro.au> for SGI (SysV) patches.
Many people complained about the old way of specifying the command. Thanks to
whoever gave me the alternative which is now implemented. It is much better.
Thanks to Sten Drescher <smd@hrt213.brooks.af.mil> for the --retry and
--delay patches and giving me the idea for the --shutdown option. Evidently
some printer doesn't appreciate the socket being
close(2)d.
Randy Fischer <fischer@ucet.ufl.edu> finally prodded me into fixing the
old lame non-handling of multi-homed host.
COPYRIGHT¶
Copyright (C) 1992-98 Robert Forsman
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; either version 2 of the License, or (at your option) any later
version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 675 Mass
Ave, Cambridge, MA 02139, USA.
AUTHOR¶
Robert Forsman
thoth@purplefrog.com
Purple Frog Software
http://web.purplefrog.com/~thoth/