The open() call returned #EBUSY 16 /* Device or resource busy */ But I don't see it anything occupying it with "sudo lsof" I see it only when I attach it with screen (or sudo screen to be precise).
I also looked into strace, but I don't see anything difference between the succeeded first connection and the failed subsequent connection. At this point, I think I am stuck. :-( thanks, Joe. On Fri, Jun 5, 2020 at 1:05 AM Marcin Cieslak <sa...@saper.info> wrote: > On Thu, 4 Jun 2020, Joe Yeung wrote: > > > Thanks for your response. > > I am a bit busy today and wasn’t able collect the errno from the failed > open() call. > > I think screen prints that out too - in my case screen was saying > Permission denied as well. > > > My system is running Yocto with screen 4.8 but this issue is also > observable on Ubuntu. > > > > In your case where the pts jumps from 3 to 4, how did you find out it > had gone to 4 in the first place? > > One of my challenges is to find out what pts qemu uses when I spun up > the VM. Fortunately it is displayed on the command line. If it is to jump > around like your set up, that would be painful because at any instance of > time, you wouldn’t know which pts to use. > > I just did ls /dev/pts and observed changes there (FreeBSD has its own > devfs probably similar to > the Linux one). It was interesting to see 0 1 2 3 listed and then 0 1 2 4 > and then back to 0 1 2 3 > and so forth... > > Intestesting note in the pty(4) manpage: > > BUGS > Unlike previous implementations, the master and slave device nodes > are > destroyed when the PTY becomes unused. A call to stat(2) on a > nonexistent master device will already cause a new master device > node to > be created. The master device can only be destroyed by opening and > closing it. >
