mount_nfs does not like exports longer then 88 chars

[Rick Macklem]

Mark Saad wrote:
> On Thu, Apr 19, 2012 at 3:51 PM, Andrew Duane <aduane at juniper.net>
> wrote:
> > MNAMELEN is used to bound the Mount NAMe LENgth, and is used in many
> > many places. It may seem to work fine, but there are lots of
> > utilities and such that will almost certainly fail managing it.
> > Search the source code for MNAMELEN.....
> 
> I see that this is used in a number of Mount and fs bits. Do you know
> why mount_nfs would care how long the exported path and hostname are ?
> 
Well, it's copied to f_mntfromname in "struct statfs". If one longer
than MNAMELEN is allowed, it gets truncated when copied. I have no idea
which userland apps. will get upset with a truncated value in
f_mntfromname. (To change the size of f_mntfromname would require a new
revision of the statfs syscall, I think?)

Does this answer what you were asking? rick

> >
> >  ...................................
> > Andrew Duane
> > Juniper Networks
> > +1 978-589-0551 (o)
> > +1 603-770-7088 (m)
> > aduane at juniper.net
> >
> >
> >
> >
> >> -----Original Message-----
> >> From: owner-freebsd-hackers at freebsd.org [mailto:owner-freebsd-
> >> hackers at freebsd.org] On Behalf Of Mark Saad
> >> Sent: Thursday, April 19, 2012 3:46 PM
> >> To: freebsd-hackers at freebsd.org
> >> Subject: mount_nfs does not like exports longer then 88 chars
> >>
> >> Hello Hackers
> >>   I was wondering if anyone has come across this issue. This exists
> >>   in
> >> FreeBSD 6, 7, and 9 , and probably in 8 but I am not using it at
> >> this time.
> >> When a nfs export path and host name total to more then 88
> >> characters
> >> mount_nfs bombs out with the following error when it attempts to
> >> mount it.
> >>
> >> mount_nfs:
> >> nyisilon2-13.grp2:/ifs/clients/www/csar884520456/files_cms-
> >> stage-BK/imagefield_default_images:
> >> File name too long
> >>
> >> I traced this down to a check in mount_nfs.c . This is about line
> >> 560
> >> in the 7-STABLE version and 734 in the 9-STABLE version
> >>
> >>
> >>         /*
> >>          * If there has been a trailing slash at mounttime it seems
> >>          * that some mountd implementations fail to remove the
> >>          mount
> >>          * entries from their mountlist while unmounting.
> >>          */
> >>         for (speclen = strlen(spec);
> >>                 speclen > 1 && spec[speclen - 1] == '/';
> >>                 speclen--)
> >>                 spec[speclen - 1] = '\0';
> >>         if (strlen(hostp) + strlen(spec) + 1 > MNAMELEN) {
> >>                 warnx("%s:%s: %s", hostp, spec,
> >>                 strerror(ENAMETOOLONG));
> >>                 return (0);
> >>         }
> >>
> >> Does any one know why the check for hostp + spec +1 to be less then
> >> MNAMELEN is there for ?
> >>
> >>  I removed the check on my 9-STABLE box and it mounts the long
> >>  mounts fine
> >>
> >> I submitted a pr for this its kern/167105
> >> http://www.freebsd.org/cgi/query-pr.cgi?pr=167105 as there is no
> >> mention of this in the man page and I cant find any reason for the
> >> check at all.
> >>
> >>
> >> --
> >> mark saad | nonesuch at longcount.org
> >> _______________________________________________
> >> freebsd-hackers at freebsd.org mailing list
> >> http://lists.freebsd.org/mailman/listinfo/freebsd-hackers
> >> To unsubscribe, send any mail to "freebsd-hackers-
> >> unsubscribe at freebsd.org"
> 
> 
> 
> --
> mark saad | nonesuch at longcount.org
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