lib32 biarch support and libnss-extrausers

[Loïc Minier]

Hi,

in our images, the ubuntu user is not in the shipped /etc/passwd NSS
database, but in /var/lib/extrausers/passwd. (This is to make sure that OS
usernames and locally created users dont clash, e.g. if an OS update adds a
system user id such as dbus or systemd and ships file owned by that system
user, it should not collide with a locally created user id.)

libnss-extrausers is a libc extension and gets loaded automatically so that
running "getent passwd" or doing the equivalent getpwnam libc calls returns
both system users and local users, such as the ubuntu user.

However, while 32-bits programs on a 64-bits snappy system generally work
fine, the ubuntu user is not returned from a 32-bits program. You can try
this by running "getent passwd" with i386 getent extracted from libc-bin on
a 64-bits snappy: it will list all system users but not ubuntu.

libnss-extrausers *does* ship a 32-bits version, but under the legacy
/usr/lib32; I had originally filed LP #1551321
<https://bugs.launchpad.net/ubuntu/+source/libnss-extrausers/+bug/1551321>
thinking
this was purely a libnss-extrausers issues, but it turns out it's both
 snappy and a libnss-extrausers issue. So two things:
- I believe we should change libnss-extrausers to use multiarch pathnames
instead of the legacy lib32 ones
- do we want to support lib32 in snappy? this would be achieved with a
ld.so.conf.d config provided by libc6-i386, so basically we'd just add
libc6-i386 to the image

Thanks,
- Loïc Minier
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.ubuntu.com/archives/snappy-devel/attachments/20160321/9155dcec/attachment.html>