Date: Thu, 19 Apr 2012 23:27:22 -0400 From: Mark Saad <nonesuch@longcount.org> To: Rick Macklem <rmacklem@uoguelph.ca> Cc: "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org> Subject: Re: mount_nfs does not like exports longer then 88 chars Message-ID: <A442606C-A0E9-49D7-B1BD-4A1F687571F9@longcount.org> In-Reply-To: <182169197.3115940.1334883529079.JavaMail.root@erie.cs.uoguelph.ca> References: <182169197.3115940.1334883529079.JavaMail.root@erie.cs.uoguelph.ca>
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On Apr 19, 2012, at 8:58 PM, Rick Macklem <rmacklem@uoguelph.ca> wrote:
> Mark Saad wrote:
>> On Thu, Apr 19, 2012 at 3:51 PM, Andrew Duane <aduane@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.....
>>=20
>> 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 ?
>>=20
> 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?)
>=20
> Does this answer what you were asking? rick
>=20
Yes and no, it smells like a bug ,in so far as its not mentioned anywhere ou=
t there . A one line addition to mount_nfs man page stipulating that there i=
s a known limit on the length of the host name and source export would be he=
lpful. =20
On the other hand 88 bytes seams like an odd size to me . The check for the=
size happens twice in the 7-stable code ,for mount_nfs, and only once in th=
e 9-stable code . Not sure why either, and i did bot research it yet. In th=
e mean time I am going to take a peak at the other bsd's and see if there is=
a solution .=20
>>>=20
>>> ...................................
>>> Andrew Duane
>>> Juniper Networks
>>> +1 978-589-0551 (o)
>>> +1 603-770-7088 (m)
>>> aduane@juniper.net
>>>=20
>>>=20
>>>=20
>>>=20
>>>> -----Original Message-----
>>>> From: owner-freebsd-hackers@freebsd.org [mailto:owner-freebsd-
>>>> hackers@freebsd.org] On Behalf Of Mark Saad
>>>> Sent: Thursday, April 19, 2012 3:46 PM
>>>> To: freebsd-hackers@freebsd.org
>>>> Subject: mount_nfs does not like exports longer then 88 chars
>>>>=20
>>>> 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.
>>>>=20
>>>> mount_nfs:
>>>> nyisilon2-13.grp2:/ifs/clients/www/csar884520456/files_cms-
>>>> stage-BK/imagefield_default_images:
>>>> File name too long
>>>>=20
>>>> 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
>>>>=20
>>>>=20
>>>> /*
>>>> * 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 =3D strlen(spec);
>>>> speclen > 1 && spec[speclen - 1] =3D=3D '/';
>>>> speclen--)
>>>> spec[speclen - 1] =3D '\0';
>>>> if (strlen(hostp) + strlen(spec) + 1 > MNAMELEN) {
>>>> warnx("%s:%s: %s", hostp, spec,
>>>> strerror(ENAMETOOLONG));
>>>> return (0);
>>>> }
>>>>=20
>>>> Does any one know why the check for hostp + spec +1 to be less then
>>>> MNAMELEN is there for ?
>>>>=20
>>>> I removed the check on my 9-STABLE box and it mounts the long
>>>> mounts fine
>>>>=20
>>>> I submitted a pr for this its kern/167105
>>>> http://www.freebsd.org/cgi/query-pr.cgi?pr=3D167105 as there is no
>>>> mention of this in the man page and I cant find any reason for the
>>>> check at all.
>>>>=20
>>>>=20
>>>> --
>>>> mark saad | nonesuch@longcount.org
>>>> _______________________________________________
>>>> freebsd-hackers@freebsd.org mailing list
>>>> http://lists.freebsd.org/mailman/listinfo/freebsd-hackers
>>>> To unsubscribe, send any mail to "freebsd-hackers-
>>>> unsubscribe@freebsd.org"
>>=20
>>=20
>>=20
>> --
>> mark saad | nonesuch@longcount.org
>> _______________________________________________
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