NFSSVC(2)                   BSD System Calls Manual                  NFSSVC(2)

NAME
     nfssvc -- NFS services

SYNOPSIS
     #include <unistd.h>
     #include <nfs/nfs.h>

     int
     nfssvc(int flags, void *argstructp);

DESCRIPTION
     The nfssvc() function is used by the NFS server daemon to pass informa-
     tion into and out of the kernel and also to enter the kernel as a server
     daemon.  The flags argument consists of several bits that show what
     action is to be taken once in the kernel and the argstructp points to any
     corresponding data that the action may require.

     nfssvc() is called with the flag NFSSVC_NFSD and a NULL argstructp to
     enter the kernel as an nfsd(8) daemon.  The NFSSVC_NFSD action normally
     does not return until the NFS server is stopped.

     The nfsd(8) server daemon calls nfssvc() with the flag NFSSVC_ADDSOCK and
     a pointer to a

     struct nfsd_args {
             int     sock;           /* Socket to serve */
             caddr_t name;           /* Client address for connection based sockets */
             int     namelen;        /* Length of name */
     };

     to pass a server side NFS socket into the kernel for servicing by the
     nfsd(8) daemons.

     The nfsd(8) server daemon calls nfssvc() with the flag NFSSVC_EXPORT and
     a pointer to a

     struct nfs_export_args {
             uint32_t                nxa_fsid;       /* export FS ID */
             uint32_t                nxa_expid;      /* export ID */
             char                    *nxa_fspath;    /* export FS path */
             char                    *nxa_exppath;   /* export sub-path */
             uint32_t                nxa_flags;      /* export arg flags */
             uint32_t                nxa_netcount;   /* #entries in ex_nets array */
             struct nfs_export_net_args *nxa_nets;   /* array of net args */
     };

     to pass exported file system information into the kernel.

RETURN VALUES
     Upon successful completion, a value of 0 is returned.  Otherwise, -1 is
     returned the global variable errno is set to specify the error.

ERRORS
     [EPERM]            The caller is not the super-user.

     [EINVAL]           The action specified by the flags argument was not
                        valid.

     [EFAULT]           argstructp points to an invalid address.

     [ENOMEM]           A memory allocation failure prevented the action from
                        completing.

     [EEXIST]           An attempt was made to add a UDP socket via the
                        NFSSVC_ADDSOCK action, but the UDP socket has already
                        been added.

SEE ALSO
     nfsd(8)

HISTORY
     The nfssvc function first appeared in 4.4BSD.

BUGS
     The nfssvc system call is designed specifically for the NFS server dae-
     mons and as such is specific to their requirements.  Several fields of
     the argument structures are assumed to be valid, such that nfssvc must be
     used with extreme care.

BSD                             January 9, 2007                            BSD