Public bug reported: Browsing the eglibc mailing list archives I notice[0] that the eglibc resolver has been enhanced[1] such that if /etc/resolv.conf's mtime changes then the client is asked to re-initialize the resolver state. I haven't tested the code, but if I understand the feature correctly it gives us an opportunity to eliminate from /etc/resolvconf/update.d/libc the code that restarts nscd. That would be a desirable simplification. Ditto for some other resolvconf update scripts.
We can't go ahead and eliminate the nscd-restart code yet for a simple reason. The eglibc resolver monitors /etc/resolv.conf and thus watches the mtime of the symlink, not the target, whereas of course resolvconf modifies the target.[2] ret = stat (_PATH_RESCONF, &statbuf); [...] if ((ret == 0) && (last_mtime != statbuf.st_mtime)) { last_mtime = statbuf.st_mtime; atomicinc (__res_initstamp); } The first question is, can we take advantage of this eglibc enhancement in order to simplify resolvconf update scripts? Second question: do we want to? If so, then the third question is, what's the best way to enhance the new eglibc feature so that we can take advantage of it? Should the eglibc code be changed so that, in addition to noticing a change in the mtime of /etc/resolv.conf, it also notices a change in the mtime of the target of /etc/resolv.conf if the latter is a symbolic link? [0]http://www.eglibc.org/archives/patches/msg00977.html [1]http://patch-tracker.debian.org/patch/series/view/eglibc/2.11.3-4/any/submitted-resolv.conf-thread.diff [2]Quoted code is at line 102 of resolv/res_libc.c ** Affects: resolvconf (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1110331 Title: Enhance glibc to monitor mtime of resolv.conf To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/resolvconf/+bug/1110331/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs