nfsclnt(2) [osx man page]

NFSCLNT(2)						      BSD System Calls Manual							NFSCLNT(2)

NAME

     nfsclnt -- NFS client services

SYNOPSIS

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

     int
     nfsclnt(int flags, void *argstructp);

DESCRIPTION

     The nfsclnt() function is used by the NFS client daemons to pass information into and out of the kernel.  The flags argument consists of sev-
     eral 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.

     rpc.lockd(8) calls nfsclnt() with the flag NFSCLNT_LOCKDANS and a pointer to a

     struct lockd_ans {
	     int	     la_version;	     /* lockd_ans version */
	     int	     la_errno;		     /* return status */
	     u_int64_t	     la_xid;		     /* unique message transaction ID */
	     int	     la_flags;		     /* answer flags */
	     pid_t	     la_pid;		     /* pid of lock requester/owner */
	     off_t	     la_start;		     /* lock starting offset */
	     off_t	     la_len;		     /* lock length */
	     int	     la_fh_len; 	     /* The file handle length. */
	     u_int8_t	     la_fh[NFSV3_MAX_FH_SIZE];/* The file handle. */
     };

     to pass the response to an NFS file locking request back into the kernel.

RETURN VALUES

     Upon successful completion, a value of 0 is returned.  Otherwise, -1 is returned and 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.

     [EPIPE]		The response doesn't match any currently-outstanding lock request.

SEE ALSO

     rpc.lockd(8)

BUGS

     The nfsclnt system call is designed specifically for the NFS client daemons and as such is specific to their requirements.  Several fields of
     the argument structures are assumed to be valid, such that nfsclnt must be used with extreme care.

BSD
								  January 9, 2007							       BSD

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

NAME

     nfssvc -- NFS services

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

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

     int
     nfssvc(int flags, void *argstructp);

DESCRIPTION

     The nfssvc() function is used by the NFS daemons to pass information into and out of the kernel and also to enter the kernel as a server dae-
     mon.  The flags argument consists of several bits that show what action is to be taken once in the kernel and the argstructp points to one of
     three structures depending on which bits are set in flags.

   Calls used by nfsd(8)
     On the server side, nfssvc() is called with the flag NFSSVC_NFSD and a pointer to a

     struct nfsd_srvargs {
	     struct nfsd     *nsd_nfsd;      /* Pointer to in kernel nfsd struct */
	     uid_t	     nsd_uid;	     /* Effective uid mapped to cred */
	     u_long	     nsd_haddr;      /* Ip address of client */
	     struct ucred    nsd_cr;	     /* Cred. uid maps to */
	     int	     nsd_authlen;    /* Length of auth string (ret) */
	     char	     *nsd_authstr;   /* Auth string (ret) */
     };

     to enter the kernel as an nfsd(8) daemon.	Whenever an nfsd(8) daemon receives a Kerberos authentication ticket, it will return from nfssvc()
     with errno set to ENEEDAUTH.  The nfsd(8) will attempt to authenticate the ticket and generate a set of credentials on the server for the
     ``user id'' specified in the field nsd_uid.  This is done by first authenticating the Kerberos ticket and then mapping the Kerberos principal
     to a local name and getting a set of credentials for that user via getpwnam(3) and getgrouplist(3).  If successful, the nfsd(8) will call
     nfssvc() with the NFSSVC_NFSD and NFSSVC_AUTHIN flags set to pass the credential mapping in nsd_cr into the kernel to be cached on the server
     socket for that client.  If the authentication failed, nfsd(8) calls nfssvc() with the flags NFSSVC_NFSD and NFSSVC_AUTHINFAIL to denote an
     authentication failure.

     The master 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.

   Calls used by mountd(8)
     The mountd(8) server daemon calls nfssvc() with the flag NFSSVC_SETEXPORTSLIST and a pointer to a struct mountd_exports_list object to atomi-
     cally change the exports lists of a specific file system.	This structure has the following fields:

     const char *mel_path  Path to the file system that will have its exports list replaced by the one described in the other fields.

     size_t mel_nexports   Number of valid entries in the mel_export field.  If zero, the exports list will be cleared for the given file system.

     struct export_args mel_export[AF_MAX]
			   Set of exports to be used for the given file system.

RETURN VALUES

     Usually nfssvc does not return unless the server is terminated by a signal when a value of 0 is returned.	Otherwise, -1 is returned and the
     global variable errno is set to specify the error.

ERRORS

     [ENEEDAUTH]	This special error value is really used for authentication support, particularly Kerberos, as explained above.

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

SEE ALSO

     mount_nfs(8), nfsd(8)

HISTORY

     The nfssvc function first appeared in 4.4BSD.

BUGS

     The nfssvc system call is designed specifically for the NFS support daemons and as such is specific to their requirements.  It should really
     return values to indicate the need for authentication support, since ENEEDAUTH is not really an error.  Several fields of the argument struc-
     tures are assumed to be valid and sometimes to be unchanged from a previous call, such that nfssvc must be used with extreme care.

BSD
								 December 30, 2006							       BSD