From: Jean-Pol Guillement (Jean-Pol.Guillement@math.univ-nantes.fr)
Date: Mon Nov 10 2003 - 09:51:17 EST
Thanks to
Fred.van.Kempen Fred.van.Kempen@microwalt.nl
Dr Thomas.Blinn tpb@doctor.zk3.dec.com
Paolo Lucente pl@ba.cnr.it
who point me looking for rpc.lockd.
Paolo Lucente also indicates http://nfs.sourceforge.net
where I find the following solution.
I have successfully experimented the "no_auth_nlm" export option.
Many thanks,
Jean-Pol Guillement
---------------------------------------------------------------------------
(Ref http://nfs.sourceforge.net/#section_e)
E. Using Linux NFS with alternate platforms
E1. I use a Tru64 Unix 4.x or SunOS 4.1.x client. NFS File locking does not
seem to work unless I give all users permissions on the file.
A. The default specifications for NFS versions 2 and 3 allow any user to
lock a file regardless whether that user has permission to access the file. The
writers of the Linux NFS server regarded this behavior as insecure, and chose
to only allow users who have access to a file to be able to lock it. However,
older SunOS and Tru64 clients take advantage of the NFS specification by making
all NFS file lock requests with the credentials of the daemon. This means that
if the daemon does not have access to the files, the server will refuse to lock
them.
Solution: The export option "no_auth_nlm" is designed to alleviate this
problem. Set it on any directories you wish to export to these clients. This
will disable the authorization check on file lock requests. The option is
expected to first be available in standard kernels 2.2.16 and nfs-utils 0.1.7,
however they are currently available from the dhiggen kernel patches.
---------------------------------------------------------------------------
The original post:
> Dear managers,
>
> Can somebody explain me the behavior of the lockf function
> on a Tru64, 4.0F, Alpha-server 1000A with NFS mounted files ?
>
> The following is a part of a program named testlock:
>
> ...
> if ((fd=open(atester,O_WRONLY)) < 0) {
> printf("impossible ouvrir %s.\n",atester);
> exit(1);
> }
> t=lockf(fd,F_TEST,0);
> if (t) {
> printf("%s est locke',\nt=%d,errno = %d\n",
> atester,t,errno);
> printf("EBADF=%d,EACCES=%d,EAGAIN=%d,EDEADLK=%d\n\
> EINTR=%d,EINVAL=%d,EOPNOTSUPP=%d\n",
> EBADF,EACCES,EAGAIN,EDEADLK,EINTR,EINVAL,
> EOPNOTSUPP);
> } else {
> printf("%s pas locke'.\n",atester);
> }
> ...
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> test 1:
> touch /tmp/e; chmod 600 /tmp/e; testlock -> not locked
> (and the same on any not nfs mounted file).
>
> test 2:
> /usr/users/namath is an nfs mounted directory from a linux box
> by the following fstab (lebesgue) entry
> /usr/users/namath@condorcet /usr/users/namath nfs
> rw,bg,rsize=8192,wsize=8192,hard,intr,nfsvers=3 0 0
> and the exports line on the linux system (condorcet)
> /usr/users/namath lebesgue(rw,no_root_squash)
>
> cd /usr/users/namath/myhome
> touch e; chmod 600 e; testlock -> locked (errno=EACCES)
> chmod 640 e; testlock -> locked (errno=EACCES)
> chmod 644 e; testlock -> not locked
>
> test 3:
> On an other linux box, on the same nfs mounted directory,
> testlock gives always not locked.
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