On 04.07.20 02:21, Scott Talbert wrote: > On Fri, 3 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