This is the mail archive of the
glibc-bugs@sourceware.org
mailing list for the glibc project.
[Bug nscd/14906] inotify failed when /etc/hosts file change
- From: "binli at opensuse dot org" <sourceware-bugzilla at sourceware dot org>
- To: glibc-bugs at sources dot redhat dot com
- Date: Mon, 03 Dec 2012 10:40:11 +0000
- Subject: [Bug nscd/14906] inotify failed when /etc/hosts file change
- Auto-submitted: auto-generated
- References: <bug-14906-131@http.sourceware.org/bugzilla/>
http://sourceware.org/bugzilla/show_bug.cgi?id=14906
--- Comment #2 from Bin Li <binli at opensuse dot org> 2012-12-03 10:40:11 UTC ---
Miklos Szeredi 2012-10-15 15:27:29 UTC
(In reply to comment #20)
> I can make the program work as expected also in the light of overwriting
> renames, when I'm handling a IN_IGNORED event by recreating the watch on
> /etc/hosts, like this in the inner loop:
>
> if (buf.wd == watch && (buf.mask & IN_IGNORED) != 0)
> {
> /* Recreate watch */
> watch = inotify_add_watch (fd, "/etc/hosts", IN_DELETE_SELF |
> IN_MODIFY /* | IN_MOVE */);
> printf ("Added watch on /etc/hosts, as watch %d\n", watch);
> if (watch < 0)
> bark ("inotify_add_watch");
> }
>
> That's for sure surprising limitation of the interface. Is this really how
> it's supposed to be used?
The watch descriptor returned by inotify_add_watch() refers to the inode, not
the path name. This is analogous to open(2) returning a file descriptor that
refers to the inode, not the pathname.
So yes, adding IN_DELETE_SELF and IN_MOVE_SELF to the watches is a good way to
monitor whether changes to the file _name_ were made.
Note: inotify is an unreliable interface by design and the application should
provide a backup mechanism for theoretical cases when events are lost (e.g. by
checking the modification time of the file periodically).
Also see "Limitations and caveats" section in the inofity(7) manpage.
--
Configure bugmail: http://sourceware.org/bugzilla/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are on the CC list for the bug.