1.\" Copyright (c) 1989, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)exports.5 8.3 (Berkeley) 3/29/95 33.\" $FreeBSD$ 34.\" 35.Dd March 29, 1995 36.Dt EXPORTS 5 37.Os 38.Sh NAME 39.Nm exports 40.Nd define remote mount points for 41.Tn NFS 42mount requests 43.Sh SYNOPSIS 44.Nm 45.Sh DESCRIPTION 46The 47.Nm 48file specifies remote mount points for the 49.Tn NFS 50mount protocol per the 51.Tn NFS 52server specification; see 53.%T "Network File System Protocol Specification" , 54RFC1094, Appendix A and 55.%T "NFS: Network File System Version 3 Specification" , 56Appendix I. 57.Pp 58Each line in the file 59(other than comment lines that begin with a #) 60specifies the mount point(s) and export flags within one local server 61filesystem for one or more hosts. 62A host may be specified only once for each local filesystem on the 63server and there may be only one default entry for each server 64filesystem that applies to all other hosts. 65The latter exports the filesystem to the ``world'' and should 66be used only when the filesystem contains public information. 67.Pp 68In a mount entry, 69the first field(s) specify the directory path(s) within a server filesystem 70that can be mounted on by the corresponding client(s). 71There are two forms of this specification. 72The first is to list all mount points as absolute 73directory paths separated by whitespace. 74The second is to specify the pathname of the root of the filesystem 75followed by the 76.Fl alldirs 77flag; 78this form allows the host(s) to mount at any point within the filesystem, 79including regular files if the 80.Fl r 81option is used on 82.Xr mountd 8 . 83The pathnames must not have any symbolic links in them and should not have 84any "." or ".." components. 85Mount points for a filesystem may appear on multiple lines each with 86different sets of hosts and export options. 87.Pp 88The second component of a line specifies how the filesystem is to be 89exported to the host set. 90The option flags specify whether the filesystem 91is exported read-only or read-write and how the client uid is mapped to 92user credentials on the server. 93.Pp 94Export options are specified as follows: 95.Pp 96.Sm off 97.Fl maproot No = Sy user 98.Sm on 99The credential of the specified user is used for remote access by root. 100The credential includes all the groups to which the user is a member 101on the local machine (see 102.Xr id 1 ) . 103The user may be specified by name or number. 104.Pp 105.Sm off 106.Fl maproot No = Sy user:group1:group2:... 107.Sm on 108The colon separated list is used to specify the precise credential 109to be used for remote access by root. 110The elements of the list may be either names or numbers. 111Note that user: should be used to distinguish a credential containing 112no groups from a complete credential for that user. 113.Pp 114.Sm off 115.Fl mapall No = Sy user 116.Sm on 117or 118.Sm off 119.Fl mapall No = Sy user:group1:group2:... 120.Sm on 121specifies a mapping for all client uids (including root) 122using the same semantics as 123.Fl maproot . 124.Pp 125The option 126.Fl r 127is a synonym for 128.Fl maproot 129in an effort to be backward compatible with older export file formats. 130.Pp 131In the absence of 132.Fl maproot 133and 134.Fl mapall 135options, remote accesses by root will result in using a credential of -2:-2. 136All other users will be mapped to their remote credential. 137If a 138.Fl maproot 139option is given, 140remote access by root will be mapped to that credential instead of -2:-2. 141If a 142.Fl mapall 143option is given, 144all users (including root) will be mapped to that credential in 145place of their own. 146.Pp 147The 148.Fl kerb 149option specifies that the Kerberos authentication server should be 150used to authenticate and map client credentials. 151This option requires that the kernel be built with the NFSKERB option. 152The use of this option will prevent the kernel from compiling 153unless calls to the appropriate Kerberos encryption routines 154are provided in the NFS source. 155.Pp 156The 157.Fl ro 158option specifies that the filesystem should be exported read-only 159(default read/write). 160The option 161.Fl o 162is a synonym for 163.Fl ro 164in an effort to be backward compatible with older export file formats. 165.Pp 166.Tn WebNFS 167exports strictly according to the spec (RFC 2054 and RFC 2055) can 168be done with the 169.Fl public 170flag. 171However, this flag in itself allows r/w access to all files in 172the filesystem, not requiring reserved ports and not remapping uids. 173It 174is only provided to conform to the spec, and should normally not be used. 175For a 176.Tn WebNFS 177export, 178use the 179.Fl webnfs 180flag, which implies 181.Fl public , 182.Sm off 183.Fl mapall No = Sy nobody 184.Sm on 185and 186.Fl ro . 187.Pp 188A 189.Sm off 190.Fl index No = Sy file 191.Sm on 192option can be used to specify a file whose handle will be returned if 193a directory is looked up using the public filehandle ( 194.Tn WebNFS ) . 195This is to mimic the behavior of URLs. 196If no 197.Fl index 198option is specified, a directory filehandle will be returned as usual. 199The 200.Fl index 201option only makes sense in combination with the 202.Fl public 203or 204.Fl webnfs 205flags. 206.Pp 207The third component of a line specifies the host set to which the line applies. 208The set may be specified in three ways. 209The first way is to list the host name(s) separated by white space. 210(Standard Internet ``dot'' addresses may be used in place of names.) 211The second way is to specify a ``netgroup'' as defined in the netgroup file (see 212.Xr netgroup 5 ) . 213The third way is to specify an Internet subnetwork using a network and 214network mask that is defined as the set of all hosts with addresses within 215the subnetwork. 216This latter approach requires less overhead within the 217kernel and is recommended for cases where the export line refers to a 218large number of clients within an administrative subnet. 219.Pp 220The first two cases are specified by simply listing the name(s) separated 221by whitespace. 222All names are checked to see if they are ``netgroup'' names 223first and are assumed to be hostnames otherwise. 224Using the full domain specification for a hostname can normally 225circumvent the problem of a host that has the same name as a netgroup. 226The third case is specified by the flag 227.Sm off 228.Fl network No = Sy netname 229.Sm on 230and optionally 231.Sm off 232.Fl mask No = Sy netmask . 233.Sm on 234If the mask is not specified, it will default to the mask for that network 235class (A, B or C; see 236.Xr inet 4 ) . 237.Pp 238For example: 239.Bd -literal -offset indent 240/usr /usr/local -maproot=0:10 friends 241/usr -maproot=daemon grumpy.cis.uoguelph.ca 131.104.48.16 242/usr -ro -mapall=nobody 243/u -maproot=bin: -network 131.104.48 -mask 255.255.255.0 244/u2 -maproot=root friends 245/u2 -alldirs -kerb -network cis-net -mask cis-mask 246.Ed 247.Pp 248Given that 249.Sy /usr , 250.Sy /u 251and 252.Sy /u2 253are 254local filesystem mount points, the above example specifies the following: 255.Sy /usr 256is exported to hosts 257.Em friends 258where friends is specified in the netgroup file 259with users mapped to their remote credentials and 260root mapped to uid 0 and group 10. 261It is exported read-write and the hosts in ``friends'' can mount either /usr 262or /usr/local. 263It is exported to 264.Em 131.104.48.16 265and 266.Em grumpy.cis.uoguelph.ca 267with users mapped to their remote credentials and 268root mapped to the user and groups associated with ``daemon''; 269it is exported to the rest of the world as read-only with 270all users mapped to the user and groups associated with ``nobody''. 271.Pp 272.Sy /u 273is exported to all hosts on the subnetwork 274.Em 131.104.48 275with root mapped to the uid for ``bin'' and with no group access. 276.Pp 277.Sy /u2 278is exported to the hosts in ``friends'' with root mapped to uid and groups 279associated with ``root''; 280it is exported to all hosts on network ``cis-net'' allowing mounts at any 281directory within /u2 and mapping all uids to credentials for the principal 282that is authenticated by a Kerberos ticket. 283.Pp 284The 285.Xr mountd 8 286utility can be made to re-read the 287.Nm 288file by sending it a hangup signal as follows: 289.Bd -literal -offset indent 290kill -s HUP `cat /var/run/mountd.pid` 291.Ed 292.Pp 293After sending the 294.Dv SIGHUP , 295check the 296.Xr syslogd 8 297output to see whether 298.Xr mountd 8 299logged any parsing errors in the 300.Nm 301file. 302.Sh FILES 303.Bl -tag -width /etc/exports -compact 304.It Pa /etc/exports 305the default remote mount-point file 306.El 307.Sh SEE ALSO 308.Xr netgroup 5 , 309.Xr mountd 8 , 310.Xr nfsd 8 , 311.Xr showmount 8 312.Sh BUGS 313The export options are tied to the local mount points in the kernel and 314must be non-contradictory for any exported subdirectory of the local 315server mount point. 316It is recommended that all exported directories within the same server 317filesystem be specified on adjacent lines going down the tree. 318You cannot specify a hostname that is also the name of a netgroup. 319Specifying the full domain specification for a hostname can normally 320circumvent the problem. 321