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attachment-37701-0.html	text/html	2016-03-09 05:17:15 UTC	2.33 KB	no flags	Details

This sounds like a great solution!!!<br><div class="gmail_quote"><div dir="ltr">On Tue, Mar 8, 2016 at 9:07 PM ebiggers3 at gmail dot com &lt;<a href="mailto:sourceware-bugzilla@sourceware.org">sourceware-bugzilla@sourceware.org</a>&gt; wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><a href="https://sourceware.org/bugzilla/show_bug.cgi?id=984" rel="noreferrer" target="_blank">https://sourceware.org/bugzilla/show_bug.cgi?id=984</a><br>
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Eric Biggers &lt;ebiggers3 at gmail dot com&gt; changed:<br>
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Â  Â  Â  Â  Â  Â  Â  Â  Â CC|Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  |ebiggers3 at gmail dot com<br>
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--- Comment #11 from Eric Biggers &lt;ebiggers3 at gmail dot com&gt; ---<br>
Please consider for inclusion in glibc the stat() patch used by Debian.Â  I<br>
recently spent a long time tracking down a problem with hostname resolution in<br>
a long-running process which ultimately turned out to be caused by glibc<br>
caching an empty /etc/resolv.conf.Â  This can occur if the network configuration<br>
is dynamic, e.g. managed by DHCP and NetworkManager.Â  From googling, it&#39;s<br>
apparent that many different programs, such as web browsers (Firefox, Chromium,<br>
etc.), have also run into this problem and have had to add hacks to work around<br>
it.<br>
<br>
Interestingly, in contrast with /etc/resolv.conf, glibc&#39;s resolver immediately<br>
recognizes changes in /etc/hosts.Â  Furthermore, /etc/hosts is always read in<br>
full.Â  It seems that if there is concern about performance of stat()ing<br>
/etc/resolv.conf, there could be an optimization made to skip reading<br>
/etc/hosts if it hasn&#39;t changed, thereby replacing about 5 system calls with 1.<br>
Â That would likely save more time per getaddrinfo() than is spent by stat()ing<br>
/etc/resolv.conf an extra time.<br>
<br>
Of course, the &quot;correct&quot; solution would be to use inotify to push changes only<br>
when they actually happen.Â  Unfortunately, glibc doesn&#39;t have an opportunity to<br>
do that.<br>
<br>
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