If there are no dynamic configuration directories configured with
dhcp-hostsdir, dhcp-optsdir and hostsdir then we need to use inotify
only to track changes to resolv-files, but we don't need to do
that when DNS is disabled (port=0) or no resolv-files are configured.
It turns out that inotify slots can be a scarce resource, so not
using one when it's not needed is a Goood Thing.
Patch by HL, description above from SRK.
Saying we've "flushed x outdated entries" is confusing, since
the count is the total number of entries in the modified file,
most of which are going to get added straight back when the file
is re-read.
The log now looks like
dnsmasq: inotify: /tmp/dir/1 (new or modified)
dnsmasq: inotify: flushed 1 addresses read from /tmp/dir/1
dnsmasq: read /tmp/dir/1 - 2 addresses
which hopefully make it more obvious that /tmp/dir/1 contained one
address before, and now contains two.
Use strlen to determine the length of the filename returned by
inotify, as in->len refers to the length of the buffer containing
the name, not the length of the name itself.
http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2018q1/011950.html
Signed-off-by: Andy Hawkins <andy@gently.org.uk>
Patch further modified by simon@thekelleys.org to avoid
out-of-bounds array access with an empty string, call strlen once,
and reverse order of filename verifcation and resolv-file test.
