ref: 294e08fa1e2481a3b01b815c34f458999d2e782c
dir: /rc/bin/srvssh/
#!/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=u9fs rawflags='' 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/$1 case 2 srv=$2 mtpt=/n/$1 case 3 srv=$2 mtpt=$3 } x=(srv $sleephack -e \ 'ssh '$rawflags' '$1' '$rawhack' '$u9fspath' -na none -u ''$''USER -l ''$''HOME/u9fs.log' \ $srv $mtpt) $x # Sometimes /srv/whatever can be a closed pipe, in which case # srv will have been killed for writing to it, without a chance to # defend itself. Rerun it in this case. ss=$status if(~ $ss *'write on closed pipe'*){ rm -f /srv/$srv $x ss=$status } if(! ~ $ss '') echo srvssh: $ss >[1=2] exit $ss