On Sat, 4 Jul 2020, Philipp Kern wrote:
I'm trying to make sure my local sbuild chroot matches the buildd's as
closely as possible. Can someone tell me what the fstab looks like on
the official buildd's? I'm looking on barriere at the chroots there
and it *appears* that the one in use is /etc/schroot/dsa/fstab, which
contains:
# fstab: static file system information for chroots.
# Note that the mount point will be prefixed by the chroot path
# (CHROOT_PATH)
#
# <file system> <mount point> <type> <options> <dump> <pass>
# Linux version
/proc /proc none rw,bind 0 0
/sys /sys none rw,bind 0 0
/dev /dev none rw,bind 0 0
/dev/pts /dev/pts none rw,bind 0 0
/home /home none rw,bind 0 0
/tmp /tmp none rw,bind 0 0
tmpfs-shm /dev/shm tmpfs defaults,size=64m 0 0
Can someone confirm that this is the fstab used on the buildd's?
Are you sure you actually care about the fstab vs. the filesystem the
build is running under? The latter is what is odd, as builds happen
within tmpfs, which has slightly different semantics than other
filesystems.
Well, what I'm actually wondering about is the permissions on /dev/ptmx.
On my local schroot, it is a symlink to /dev/pts/ptmx with root-only
permissions:
(unstable-amd64-sbuild)talbert@debian-unstable:/$ ls -l /dev/ptmx
lrwxrwxrwx 1 root root 8 Feb 5 2016 /dev/ptmx -> pts/ptmx
(unstable-amd64-sbuild)talbert@debian-unstable:/$ ls -l /dev/pts/ptmx
c--------- 1 root root 5, 2 Jun 17 19:13 /dev/pts/ptmx
On barriere, for example, it is not a symlink and has more open
permissions:
(sid_amd64-dchroot)swt2c@barriere:~$ ls -l /dev/ptmx
crw-rw-rw- 1 root tty 5, 2 Jul 4 2020 /dev/ptmx
That's what let me to the fstab question, as it seems that barriere has
/dev mounted, whereas my local schroot does not:
udev on /dev type devtmpfs
(rw,nosuid,relatime,size=4068732k,nr_inodes=1017183,mode=755)
/dev is not mounted, so it inherits the static bundle - which, to be
fair, is not the worst thing because that means it is clear which
devices exist. /dev/pts is mounted. However, as you found, /dev/ptmx is
thus a character device in itself and not a symlink to /dev/pts/ptmx.
The current, relevant fstab file is part of Puppet because it is
templated. It's available on [1].
Kind regards
Philipp Kern
[1]
https://salsa.debian.org/dsa-team/mirror/dsa-puppet/-/blob/master/modules/schroot/templates/schroot-buildd/fstab.erb
Thanks. I still wasn't able to figure out why my local schroot has
restrictive permissions on /dev/ptmx, but I was able to upload a package
and it built successfully on the buildd's (where it failed locally) so I
guess my immediate problem is resolved. :)
Scott
