[pkg-gnupg-maint] Bug#858466: schroot should mount per-user tmpfs at /run/user/$(id -u)

[Daniel Kahn Gillmor]

Source: schroot
Version: 1.6.10-1+b1
Severity: wishlist
Control: affects -1 + gnupg-agent dirmngr

As Tincho mentioned in https://bugs.debian.org/840883#20 , the lack of
/run/user/$(id -u) can be problematic for processes interacting with
per-user daemons or other per-user session mechanisms.

At the moment, nothing exists at all in /run/user inside an schroot
session.

The two obvious options i see are:

 a) bind-mount the host's /run/user children, as Tincho suggests

 b) ephemerally create a new tmpfs for the schrooting user in
    /run/user/$(id -u) if it isn't already mounted.

The problem with (a) is that the version and capabilities of the
service (e.g. dbus, gpg-agent) using /run/user/NN/ sockets in the host
may well differ from the version and capabilities needed by the
clients running inside the chroot.

So this bug report suggests a preference for (b), the more "isolated"
approach.

Upon disposal of the schroot, i'd expect the ephemerally-created tmpfs
to be recursively deleted and then unmounted.

There is a lengthy discussion over on gnupg-devel over whether
software should be able to depend on having /run/user/$(id -u)
available during its configuration, build and test.

in
https://lists.gnupg.org/pipermail/gnupg-devel/2017-March/032711.html,
Werner Koch (GnuPG upstream) points out:

> GnuPG's README now recommends the creation of /run/user.

This suggests that any software that expects to run components of
GnuPG during build or test (including GnuPG itself) is likely to have
problems building or running tests within an schroot in the future
until this issue is resolved.

Regards,

        --dkg


-- System Information:
Debian Release: 9.0
  APT prefers testing-debug
  APT policy: (500, 'testing-debug'), (500, 'testing'), (200, 'unstable-debug'), (200, 'unstable'), (1, 'experimental-debug'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.9.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)