On Sat, Jun 10, 2017 at 11:00 PM, John McKown <john.archie.mck...@gmail.com> wrote:
> On Sat, Jun 10, 2017 at 9:19 AM, Clark Wang <dearv...@gmail.com> wrote: > >> (I'm using bash 4.4.12 on Debian 8) >> >> Please follow the following steps to reproduce. >> >> From tty #1: >> >> $ tty >> /dev/pts/11 >> $ ssh -o ControlMaster=yes -o ControlPath=/tmp/socket.tmp -N -f 127.0.0.1 >> root@127.0.0.1's password: >> $ ps -C ssh uw >> USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND >> root 716 0.0 0.2 44428 692 ? Ss 22:04 0:00 ssh -o >> ControlMaster=yes -o ControlPath=/tmp/socket.tmp -N -f 127.0 >> $ >> $ >> >> ssh -o ControlMaster=no -o ControlPath=/tmp/socket.tmp 127.0.0.1 sleep >> 9999 & >> [1] 725 >> $ <-- Then I cannot input anything except CTRL-C >> >> Go to tty #2: >> >> $ ps t pts/11 jw >> PPID PID PGID SID TTY TPGID STAT UID TIME COMMAND >> 32714 725 725 32714 pts/11 32714 S 0 0:00 ssh -o >> ControlMaster=no -o ControlPath=/tmp/socket.tmp 127.0.0.1 sleep 9999 >> 579 32714 32714 32714 pts/11 32714 Ss+ 0 0:00 bash >> $ >> >> If I kill the "ssh -o ControlMaster=no -o ControlPath=/tmp/socket.tmp >> 127.0.0.1 sleep 9999" then tty #1 (pts/11) would be able to accept my >> input >> again. Seems like the background "ssh" at tty #1 is consuming all input. I >> cannot understand this since it should be stopped by SIGTTIN if it tries >> to >> read from the tty. >> >> Idea? >> >> -clark >> > > IMO, not a bug in BASH, so this is the wrong forum. But, since I'm > already blathering on, I'd say the problem is that you have invoked "ssh" > incorrectly. In particular, ssh _does_ read from stdin normally. But, from > the man page: > > -f Requests ssh to go to background just before command execution. > This is useful if ssh is going to ask for passwords > or passphrases, but the user wants it in the background. > This implies -n. The recommended way to start X11 programs > at a remote site is with something like ssh -f host xterm. > > If the ExitOnForwardFailure configuration option is set to > “yes”, then a client started with -f will wait for all > remote port forwards to be successfully established before > placing itself in the background. > > > So instead of: > > > ssh -o ControlMaster=no -o ControlPath=/tmp/socket.tmp 127.0.0.1 sleep 9999 > & > > Try: > > > ssh -f -o ControlMaster=no -o ControlPath=/tmp/socket.tmp 127.0.0.1 sleep > 9999 > Thanks but I want it to run as a background job in bash.
