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NFSSVC(2)		  FreeBSD System Calls Manual		     NFSSVC(2)

     nfssvc -- NFS services

     Standard C	Library	(libc, -lc)

     #include <sys/param.h>
     #include <sys/mount.h>
     #include <sys/time.h>
     #include <nfs/rpcv2.h>
     #include <nfsserver/nfs.h>
     #include <unistd.h>

     nfssvc(int	flags, void *argstructp);

     The nfssvc() system call 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.

     On	the client side, nfsiod(8) calls nfssvc() with the flags argument set
     to	NFSSVC_BIOD and	argstructp set to NULL to enter	the kernel as a	block
     I/O server	daemon.	 For NQNFS, mount_nfs(8) calls nfssvc()	with the
     NFSSVC_MNTD flag, optionally or'd with the	flags NFSSVC_GOTAUTH and
     NFSSVC_AUTHINFAIL along with a pointer to a

     struct nfsd_cargs {
	     char	     *ncd_dirp;	     /*	Mount dir path */
	     uid_t	     ncd_authuid;    /*	Effective uid */
	     int	     ncd_authtype;   /*	Type of	authenticator */
	     int	     ncd_authlen;    /*	Length of authenticator	string */
	     u_char	     *ncd_authstr;   /*	Authenticator string */
	     int	     ncd_verflen;    /*	and the	verifier */
	     u_char	     *ncd_verfstr;
	     NFSKERBKEY_T    ncd_key;	     /*	Session	key */

     structure.	 The initial call has only the NFSSVC_MNTD flag	set to specify
     service for the mount point.  If the mount	point is using Kerberos, then
     the mount_nfs(8) utility will return from nfssvc()	with errno ==
     ENEEDAUTH whenever	the client side	requires an ``rcmd'' authentication
     ticket for	the user.  The mount_nfs(8) utility will attempt to get	the
     Kerberos ticket, and if successful	will call nfssvc() with	the flags
     NFSSVC_MNTD and NFSSVC_GOTAUTH after filling the ticket into the
     ncd_authstr field and setting the ncd_authlen and ncd_authtype fields of
     the nfsd_cargs structure.	If mount_nfs(8)	failed to get the ticket,
     nfssvc() will be called with the flags NFSSVC_MNTD, NFSSVC_GOTAUTH	and
     NFSSVC_AUTHINFAIL to denote a failed authentication attempt.

     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 */
	     uint32_t	     nsd_haddr;	     /*	Ip address of client */
	     struct ucred    nsd_cr;	     /*	Cred. uid maps to */
	     int	     nsd_authlen;    /*	Length of auth string (ret) */
	     u_char	     *nsd_authstr;   /*	Auth string (ret) */
	     int	     nsd_verflen;    /*	and the	verifier */
	     u_char	     *nsd_verfstr;
	     struct timeval  nsd_timestamp;  /*	timestamp from verifier	*/
	     uint32_t	     nsd_ttl;	     /*	credential ttl (sec) */
	     NFSKERBKEY_T    nsd_key;	     /*	Session	key */

     to	enter the kernel as an nfsd(8) daemon.	Whenever an nfsd(8) daemon re-
     ceives a Kerberos authentication ticket, it will return from nfssvc()
     with errno	== ENEEDAUTH.  The nfsd(8) utility will	attempt	to authenti-
     cate 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	au-
     thenticating 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) utility 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.

     Normally 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.

     [ENEEDAUTH]	This special error value is really used	for authenti-
			cation support,	particularly Kerberos, as explained

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

     mount_nfs(8), nfsd(8), nfsiod(8)

     The nfssvc() system call first appeared in	4.4BSD.

     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	previ-
     ous call, such that nfssvc() must be used with extreme care.

FreeBSD	13.0			 June 9, 1993			  FreeBSD 13.0


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