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Re: configuring /var/run with newer autoconf
- From: Florian Weimer <fweimer at redhat dot com>
- To: Åukasz Stelmach <l dot stelmach at samsung dot com>
- Cc: libc-alpha at sourceware dot org
- Date: Tue, 12 Apr 2016 10:50:07 +0200
- Subject: Re: configuring /var/run with newer autoconf
- Authentication-results: sourceware.org; auth=none
- References: <87lh4pfp7w dot fsf%l dot stelmach at samsung dot com> <20160407175130 dot GS6588 at vapier dot lan> <874mbcfsfv dot fsf%l dot stelmach at samsung dot com> <5707A498 dot 1050500 at redhat dot com> <87a8l0ehml dot fsf%l dot stelmach at samsung dot com> <570BCC51 dot 6020203 at redhat dot com> <87ziszcj78 dot fsf%l dot stelmach at samsung dot com>
On 04/12/2016 10:41 AM, Åukasz Stelmach wrote:
Are you trying to automount /var itself, or is /var a directory
monitored by the automounter?
I don't exactly understand the alternative. Let me try to describe what
happens in my system.
I've got a root fs. There is the /var directory. It is empty. There is
LABEL=var /var ext4 defaults,noatime,x-systemd.automount 0 2
line in my fstab. x-systemd.automount tells systemd to mount autofs
under /var, start monitoring it for requests and mount the real ext4
file-system when a request comes.
The traditional use of an automounter is that you have a file system
directory, such as /mnt, which contains several remote file systems, and
each one is mounted on demand once you access the path.
Instead, you seem to be using the automounter to mount just a single
directory.
May I ask what is the reason for delayed mounting of /var?
The pathname is part of the ABI, so we
can't really change it for existing architectures.
I am not sure this is actually true. What is a part of ABI (as far as I
understand it) is _PATH_VARRUN defined in sysdeps/generic/paths.h and
sysdeps/unix/sysv/linux/paths.h. However, this isn't what nscd
uses. nscd has its own definitions in nscd/nscd-client.h and nscd/nscd.h
which apparently are not exported to /usr/include and are not supposed
to be used outside nscd. That means it should be possible to change the
the location wher nscd keeps its stuff without breaking ABI.
nscd is only the tip of the iceberg. Many NSS modules reference paths
under /var (such as /var/db, /var/run, or /var/lib/sss).
Florian