#!/bin/rc # Serve Unix u9fs over SSH## Basically, try each of the following until you find one that works:##	srvssh unix#	srvssh -r unix#	srvssh -R unix#	srvssh -r -s unix#	srvssh -R -s unix## and then never look back.  Note that "srvssh unix" should always# work.  It's just that if you're talking with certain sshd's, you'll get# hit by Nagle's algorithm and need to explore the other flags. # When using ssh to start u9fs, the only way to turn off# Nagle's algorithm (which kills the performance of RPC-based# protocols like 9P) is to allocate a pseudo-terminal.  The# command ssh -Rmp attempts to allocate a pseudo-terminal and# then put it in a transparent mode.  Especially when# connected to older SSH daemons, the connection ends up not# quite transparent.  To get around this, we explicity set the tty# mode on the command line as well.  The hope is that -Rmp makes# the connection transparent enough for the Tversion, and the stty# command will do the rest.  If -Rmp doesn't make the connection# transparent enough for the Tversion (but the stty commands do # make the connection fully transparent) then add "-s 5" to the srv# command to tell it to wait 5 seconds before sending the Tversion.# That should be enough time for the stty to take effect. rfork e fn usage {	echo 'usage: srvssh [-R] [-r] [-s] [-u u9fspath] system [srvname [mtpt]]' >[1=2]	exit usage} rawhack=''sleephack=()u9fspath=u9fsrawflags='' while(~ $1 -*){	switch($1){	case -r		rawflags='-Rmp'		shift	case -R		rawflags='-Rmp'		rawhack=('stty raw -echo '';''')		shift	case -s		sleephack=(-s 5)		shift	case -u		shift		u9fspath=$1		shift	case -u*		u9fspath=`{echo $1 | sed s/-u//}		shift	case *		usage	}} if(! ~ $#* 1 2 3)	usage switch($#*){case 1	srv=$1	mtpt=/n/$1case 2	srv=$2	mtpt=/n/$1case 3	srv=$2	mtpt=$3} x=(srv $sleephack -e \	'ssh '$rawflags' '$1' '$rawhack' '$u9fspath' -na none -u ''$''USER -l ''$''HOME/u9fs.log' \	$srv $mtpt)$x # Sometimes /srv/whatever can be a closed pipe, in which case# srv will have been killed for writing to it, without a chance to# defend itself.  Rerun it in this case. ss=$statusif(~ $ss *'write on closed pipe'*){	rm -f /srv/$srv	$x	ss=$status} if(! ~ $ss '')	echo srvssh: $ss >[1=2]exit $ss