Re: [lmi] Mounting proc and devpts for chroot [Was: Using Git submodules for the dependencies]

[Vadim Zeitlin]

On Mon, 23 Sep 2019 21:37:43 +0000 Greg Chicares <address@hidden> wrote:

GC> On 2019-09-23 20:05, Greg Chicares wrote:
GC> [...]
GC> > I hadn't yet set up these filesystems for my new bullseye chroot on my
GC> > new buster installation. Running lmi's unit tests failed thus:
GC> >   tee: /proc/self/fd/14: No such file or directory
GC> > so I figured I'd better mount them, thus:
GC> > 
GC> > /home/greg[0]#schroot --chroot=bullseye0 --user=root --directory=/      
GC> > /[0]#mount -t devpts -o rw,nosuid,noexec,relatime,mode=600 devpts /dev/pts
GC> > /[0]#mount -t proc -o rw,nosuid,nodev,noexec,relatime proc /proc
GC> > /[0]#exit
GC> > 
GC> > Now the 'nychthemeral_test' script runs successfully, but I can no longer
GC> > run lmi under wine. The command line where I started it just freezes (and
GC> > needs a few Ctrl-C's to regain control), and no (wine) lmi GUI appears.
GC> 
GC> [...adding the following lines to /etc/fstab and rebooting...]
GC> 
GC> > devpts /srv/chroot/bullseye0/dev/pts devpts 
rw,nosuid,noexec,relatime,mode=600,ptmxmode=000 0 0
GC> > proc   /srv/chroot/bullseye0/proc    proc   
rw,nosuid,nodev,noexec,relatime 0 0

 I'm sorry, I didn't succeed in sending my reply to your previous message
in this thread before you sent this one, but it wasn't a big loss anyhow,
as I was just saying that I had no idea what was wrong.

 One thing I can say is that I see absolutely no conceivable reason for
rebooting just to change chroot mounts.

 And my only other idea was to check if /src/chroot/bullseye0/dev/ptmx
existed as a char 5,2 device and used mode 0600, because it's the only
other thing I'm aware of which is related to terminal problems. I though
debootstrap was supposed to run MAKEDEV, but at least under Buster it's
necessary to run it manually, see

https://www.debian.org/releases/buster/amd64/apds03.en.html#idm4368

GC> That still didn't quite work, but I seem to have found the problem
GC> by running 'winecfg': I had apparently set wine to emulate a
GC> virtual desktop by default. In earlier installations, I had always
GC> kept that option turned off by default, enabling it selectively
GC> for only one or two programs other than lmi.

 Maybe the new version of Wine included in Bullseye has upgraded the config
file wrongly?

GC> Now the nychthemeral and GUI tests both succeed.

 Hooray!

GC> I have no idea why these mounts would have affected wine, but I
GC> can imagine that they might.

 I honestly can't.

GC> Here's another interesting thing I noticed when I rebooted into my
GC> old 'stretch' system: I had several chroots, and /etc/fstab mounted
GC> devpts and proc in an old chroot; but long ago I started using a
GC> newer chroot instead, yet forgot to change /etc/fstab; however,
GC> everything kept working just fine. That seems really mysterious,
GC> but I'm not going to spend time investigating it.

 As long as you only use [s]chroot to enter it, you may not have needed
pseudo-terminal support, so it's conceivable that it worked without it. But
there are plenty of other things that require either PTs or /proc, so this
does seem unlikely. Could it be that you had mounted these directories
manually and just didn't update /etc/fstab?

 Regards,
VZ

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