257 lines
6.8 KiB
Groff
257 lines
6.8 KiB
Groff
.\" $NetBSD: nfssvc.2,v 1.22 2005/09/23 20:27:10 wiz Exp $
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.\"
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.\" Copyright (c) 1989, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)nfssvc.2 8.1 (Berkeley) 6/9/93
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.\"
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.Dd September 23, 2005
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.Dt NFSSVC 2
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.Os
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.Sh NAME
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.Nm nfssvc
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.Nd NFS services
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In unistd.h
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.In nfs/nfs.h
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.Ft int
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.Fn nfssvc "int flags" "void *argstructp"
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.Sh DESCRIPTION
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The
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.Fn nfssvc
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function is used by the NFS daemons to pass information into and out
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of the kernel and also to enter the kernel as a server daemon.
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The
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.Fa flags
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argument consists of several bits that show what action is to be taken
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once in the kernel and the
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.Fa argstructp
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points to one of three structures depending on which bits are set in
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flags.
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.Ss Calls used by Xr mount_nfs 8
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On the client side,
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.Fn nfssvc
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is only used for
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.Li NQNFS .
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.Xr mount_nfs 8
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calls
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.Fn nfssvc
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with the
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.Dv NFSSVC_MNTD
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flag, optionally or'd with the flags
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.Dv NFSSVC_GOTAUTH
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and
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.Dv NFSSVC_AUTHINFAIL
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along with a pointer to a
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.Bd -literal
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struct nfsd_cargs {
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char *ncd_dirp; /* Mount dir path */
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uid_t ncd_authuid; /* Effective uid */
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int ncd_authtype; /* Type of authenticator */
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int ncd_authlen; /* Length of authenticator string */
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char *ncd_authstr; /* Authenticator string */
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};
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.Ed
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.Pp
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structure.
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The initial call has only the
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.Dv NFSSVC_MNTD
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flag set to specify service for the mount point.
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If the mount point is using Kerberos, then the
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.Xr mount_nfs 8
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daemon will return from
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.Fn nfssvc
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with errno set to
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.Er ENEEDAUTH
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whenever the client side requires an
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.Dq rcmd
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authentication ticket for the user.
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The
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.Xr mount_nfs 8
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program will attempt to get the Kerberos ticket, and if successful will call
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.Fn nfssvc
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with the flags
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.Dv NFSSVC_MNTD
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and
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.Dv NFSSVC_GOTAUTH
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after filling the ticket into the
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ncd_authstr field
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and
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setting the ncd_authlen and ncd_authtype
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fields of the nfsd_cargs structure.
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If
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.Xr mount_nfs 8
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failed to get the ticket,
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.Fn nfssvc
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will be called with the flags
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.Dv NFSSVC_MNTD ,
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.Dv NFSSVC_GOTAUTH ,
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and
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.Dv NFSSVC_AUTHINFAIL
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to denote a failed authentication attempt.
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.Ss Calls used by Xr nfsd 8
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On the server side,
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.Fn nfssvc
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is called with the flag
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.Dv NFSSVC_NFSD
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and a pointer to a
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.Bd -literal
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struct nfsd_srvargs {
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struct nfsd *nsd_nfsd; /* Pointer to in kernel nfsd struct */
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uid_t nsd_uid; /* Effective uid mapped to cred */
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u_long nsd_haddr; /* Ip address of client */
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struct ucred nsd_cr; /* Cred. uid maps to */
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int nsd_authlen; /* Length of auth string (ret) */
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char *nsd_authstr; /* Auth string (ret) */
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};
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.Ed
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.Pp
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to enter the kernel as an
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.Xr nfsd 8
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daemon.
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Whenever an
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.Xr nfsd 8
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daemon receives a Kerberos authentication ticket, it will return from
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.Fn nfssvc
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with errno set to
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.Er ENEEDAUTH .
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The
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.Xr nfsd 8
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will attempt to authenticate the ticket and generate a set of credentials
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on the server for the
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.Dq user id
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specified in the field nsd_uid.
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This is done by first authenticating the Kerberos ticket and then mapping
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the Kerberos principal to a local name and getting a set of credentials for
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that user via
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.Xr getpwnam 3
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and
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.Xr getgrouplist 3 .
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If successful, the
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.Xr nfsd 8
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will call
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.Fn nfssvc
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with the
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.Dv NFSSVC_NFSD
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and
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.Dv NFSSVC_AUTHIN
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flags set to pass the credential mapping in nsd_cr into the
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kernel to be cached on the server socket for that client.
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If the authentication failed,
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.Xr nfsd 8
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calls
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.Fn nfssvc
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with the flags
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.Dv NFSSVC_NFSD
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and
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.Dv NFSSVC_AUTHINFAIL
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to denote an authentication failure.
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.Pp
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The master
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.Xr nfsd 8
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server daemon calls
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.Fn nfssvc
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with the flag
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.Dv NFSSVC_ADDSOCK
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and a pointer to a
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.Bd -literal
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struct nfsd_args {
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int sock; /* Socket to serve */
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caddr_t name; /* Client address for connection based sockets */
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int namelen; /* Length of name */
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};
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.Ed
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.Pp
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to pass a server side
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.Tn NFS
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socket into the kernel for servicing by the
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.Xr nfsd 8
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daemons.
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.Ss Calls used by Xr mountd 8
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The
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.Xr mountd 8
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server daemon calls
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.Fn nfssvc
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with the flag
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.Dv NFSSVC_SETEXPORTSLIST
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and a pointer to a
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.Ft struct mountd_exports_list
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object to atomically change the exports lists of a specific file system.
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This structure has the following fields:
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.Bl -tag
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.It Vt const char *mel_path
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Path to the file system that will have its exports list replaced by the
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one described in the other fields.
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.It Vt size_t mel_nexports
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Number of valid entries in the
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.Vt mel_export
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field.
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If zero, the exports list will be cleared for the given file system.
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.It Vt struct export_args mel_export[AF_MAX]
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Set of exports to be used for the given file system.
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.El
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.Sh RETURN VALUES
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Usually
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.Nm
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does not return unless the server
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is terminated by a signal when a value of 0 is returned.
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Otherwise, \-1 is returned and the global variable
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.Va errno
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is set to specify the error.
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.Sh ERRORS
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.Bl -tag -width Er
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.It Bq Er ENEEDAUTH
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This special error value is really used for authentication support,
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particularly Kerberos, as explained above.
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.It Bq Er EPERM
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The caller is not the super-user.
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.El
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.Sh SEE ALSO
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.Xr mount_nfs 8 ,
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.Xr nfsd 8
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.Sh HISTORY
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The
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.Nm
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function first appeared in
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.Bx 4.4 .
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.Sh BUGS
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The
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.Nm
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system call is designed specifically for the
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.Tn NFS
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support daemons and as such is specific to their requirements.
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It should really return values to indicate the need for authentication
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support, since
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.Er ENEEDAUTH
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is not really an error.
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Several fields of the argument structures are assumed to be valid and
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sometimes to be unchanged from a previous call, such that
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.Nm
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must be used with extreme care.
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