On Mon, 19 Dec 2022, Petr Menšík via Unbound-users wrote:
Is there some plugin for automatically watching /etc/hosts file for changes
and loading them as a local data?
I am thinking about supporting unbound as a default localhost cache. But I
think many people rely on /etc/hosts changes are propagated automatically to
the cache. Dnsmasq and systemd-resolved both try to watch this file and
re-read it after changes.
Is there any existing way to populate local data automatically from it? Is it
already possible to synchronize local data in unbound with legacy text file?
Any real software uses /etc/nsswitch.conf which states something like:
hosts: files myhostname mdns4_minimal [NOTFOUND=return] dns
The "files" directory (see man nsswitch.conf) reads in /etc/hosts first.
This happens before the "dns" entry, so before unbound is used. So for
apps on localhost this should work fine? It is always read (and not
cached)
But I guess you want to make it systemd-resolved+glibc hack compatible,
where calls to gethostbyname() are intercepted outside of nsswitch by a
linux glibc hack, then fed to systemd-resolved, which I guess might do the
wrong thing by using dns before files ?
Or are you trying to work with the libunbound call of:
/* lookup from /etc/hosts before DNS lookups as people expect that */
ugh = ub_ctx_hosts(dns_ctx, "/etc/hosts");
and are afraid changes in /etc/hosts are not picked up without an
unbound restart?
I guess I feel /etc/hosts is there only for localhost apps in case of
broken DNS. The days you could leave something out of DNS by putting in
the /etc/hosts file are kinda long gone.
Perphaps you can detail a bit more of what you are looking for and what
you are afraid of ?
Paul
