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.\" $OpenBSD: nfssvc.2,v 1.17 2003/10/22 04:45:54 jmc Exp $
.\" $NetBSD: nfssvc.2,v 1.6 1995/02/27 12:35:08 cgd Exp $
.\"
.\" Copyright (c) 1989, 1991, 1993
.\" The Regents of the University of California. All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\" 3. Neither the name of the University nor the names of its contributors
.\" may be used to endorse or promote products derived from this software
.\" without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" @(#)nfssvc.2 8.1 (Berkeley) 6/9/93
.\"
.Dd June 9, 1993
.Dt NFSSVC 2
.Os
.Sh NAME
.Nm nfssvc
.Nd NFS services
.Sh SYNOPSIS
.Fd #include <unistd.h>
.Fd #include <nfs/nfs.h>
.Ft int
.Fn nfssvc "int flags" "void *argstructp"
.Sh DESCRIPTION
The
.Fn 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 daemon.
The
.Fa flags
argument consists of several bits that show what action is to be taken
once in the kernel and the
.Fa argstructp
points to one of three structures depending on which bits are set in
flags.
.Pp
On the client side, there is no longer a need to call
.Fn nfssvc
with the
.Fa flags
argument set to
.Dv NFSSVC_BIOD
since this functionality has been replaced by a
.Nm nfsiod
implementation using kernel threads.
See
.Xr nfsd 8
and
.Xr sysctl 8
for further discussion.
For
.Nm NQNFS ,
.Xr mount_nfs 8
calls
.Fn nfssvc
with the
.Dv NFSSVC_MNTD
flag, optionally or'd with the flags
.Dv NFSSVC_GOTAUTH
and
.Dv NFSSVC_AUTHINFAIL
along with a pointer to a
.Bd -literal
struct nfsd_cargs {
char *ncd_dirp; /* Mount dir path */
uid_t ncd_authuid; /* Effective uid */
int ncd_authtype; /* Type of authenticator */
u_int ncd_authlen; /* Length of authenticator string */
u_char *ncd_authstr; /* Authenticator string */
u_int ncd_verflen; /* and the verifier */
u_char *ncd_verfstr;
NFSKERBKEY_T ncd_key; /* Session key */
};
.Ed
.Pp
structure.
The initial call has only the
.Dv NFSSVC_MNTD
flag set to specify service for the mount point.
If the mount point is using Kerberos, then the
.Xr mount_nfs 8
daemon will return from
.Fn nfssvc
with
.Va errno
set to
.Er ENEEDAUTH
whenever the client side requires an
.Dq rcmd
authentication ticket for the user.
.Xr mount_nfs 8
will attempt to get the Kerberos ticket, and if successful will call
.Fn nfssvc
with the flags
.Dv NFSSVC_MNTD
and
.Dv 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
.Xr mount_nfs 8
failed to get the ticket,
.Fn nfssvc
will be called with the flags
.Dv NFSSVC_MNTD ,
.Dv NFSSVC_GOTAUTH
and
.Dv NFSSVC_AUTHINFAIL
to denote a failed authentication attempt.
.Pp
On the server side,
.Fn nfssvc
is called with the flag
.Dv NFSSVC_NFSD
and a pointer to a
.Bd -literal
struct nfsd_srvargs {
struct nfsd *nsd_nfsd; /* Pointer to in kernel nfsd struct */
uid_t nsd_uid; /* Effective uid mapped to cred */
u_int32_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 */
u_int32_t nsd_ttl; /* credential ttl (sec) */
NFSKERBKEY_T nsd_key; /* Session key */
};
.Ed
.Pp
to enter the kernel as an
.Xr nfsd 8
daemon.
Whenever an
.Xr nfsd 8
daemon receives a Kerberos authentication ticket, it will return from
.Fn nfssvc
with
.Va errno
set to
.Er ENEEDAUTH .
The
.Xr 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
.Xr getpwnam 3
and
.Xr getgrouplist 3 .
If successful, the
.Xr nfsd 8
will call
.Fn nfssvc
with the
.Dv NFSSVC_NFSD
and
.Dv 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,
.Xr nfsd 8
calls
.Fn nfssvc
with the flags
.Dv NFSSVC_NFSD
and
.Dv NFSSVC_AUTHINFAIL
to denote an authentication failure.
.Pp
The master
.Xr nfsd 8
server daemon calls
.Fn nfssvc
with the flag
.Dv NFSSVC_ADDSOCK
and a pointer to a
.Bd -literal
struct nfsd_args {
int sock; /* Socket to serve */
caddr_t name; /* Client address for connection based sockets */
int namelen; /* Length of name */
};
.Ed
.Pp
to pass a server side
.Tn NFS
socket into the kernel for servicing by the
.Xr nfsd 8
daemons.
.Sh RETURN VALUES
Normally
.Nm 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
.Va errno
is set to specify the error.
.Sh ERRORS
.Bl -tag -width Er
.It Bq Er ENEEDAUTH
This special error value
is really used for authentication support, particularly Kerberos,
as explained above.
.It Bq Er EPERM
The caller is not the superuser.
.El
.Sh SEE ALSO
.Xr mount_nfs 8 ,
.Xr nfsd 8 ,
.Xr sysctl 8
.Sh HISTORY
The
.Nm nfssvc
function first appeared in
.Bx 4.4 .
.Sh BUGS
The
.Nm nfssvc
system call is designed specifically for the
.Tn NFS
support daemons and as such is specific to their requirements.
It should really return values to indicate the need for authentication
support, since
.Er ENEEDAUTH
is not really an error.
Several fields of the argument structures are assumed to be valid and
sometimes to be unchanged from a previous call, such that
.Nm nfssvc
must be used with extreme care.
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