nfssvc(2) [osf1 man page]

nfssvc(2)							System Calls Manual							 nfssvc(2)

NAME

       nfssvc - Creates a remote NFS server

SYNOPSIS

       nfssvc(
	       unsigned long udp_so,
	       unsigned long udp_num,
	       unsigned long tcp_so,
	       unsigned long tcp_num);

PARAMETERS

       Specifies a UDP socket bound to port 2049.  Specifies the number of UDP NFS server threads to start (in the low 32 bits) and 950410 (in the
       high 32 bits).  Specifies a TCP socket bound to port 2049 after a call to listen(2).  Specifies the number of TCP  NFS  server  threads	to
       start.

DESCRIPTION

       The  use  of the nfssvc() function is not supported in customer applications, and the interface is subject to change without notice.  It is
       intended for use solely by nfsd(8).

       The nfssvc() function starts NFS server kernel threads and provides TCP connection support.  If the value of the upper 32 bits  of  udp_num
       is not 950410, TCP threads are not started.

RETURN VALUES

       The  nfssvc() function has no successful return.  In fact, it frees the text and data segments associated with the calling program so there
       is nothing to return to.  When interrupted by a KILL signal, the server threads are terminated and the process exits.  If nfssvc()  encoun-
       ters errors, -1 is returned and errno is set to indicate the error.

ERRORS

       If  the	nfssvc()  function  fails,  errno may be set to one of the following values: Another process is executing nfssvc.  An invalid file
       descriptor has been passed to the nfssvc() function.  More than 128 server and netisr threads were requested.  The caller is not the  supe-
       ruser.

RELATED INFORMATION

       Functions: async_daemon(2)

       Commands: nfsd(8) delim off

																	 nfssvc(2)

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