.\"	$OpenBSD: mount_portal.8,v 1.19 2007/05/31 19:19:45 jmc Exp $
.\"	$NetBSD: mount_portal.8,v 1.6 1995/08/18 15:01:19 pk Exp $
.\"
.\" Copyright (c) 1993, 1994
.\"	The Regents of the University of California.  All rights reserved.
.\" All rights reserved.
.\"
.\" This code is derived from software donated to Berkeley by
.\" Jan-Simon Pendry.
.\"
.\" 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.
.\"
.\"	@(#)mount_portal.8	8.3 (Berkeley) 3/27/94
.\"
.Dd $Mdocdate: May 31 2007 $
.Dt MOUNT_PORTAL 8
.Os
.Sh NAME
.Nm mount_portal
.Nd mount the portal daemon
.Sh SYNOPSIS
.Nm mount_portal
.Op Fl o Ar options
.Ar config
.Ar mount_point
.Sh DESCRIPTION
The
.Nm
command attaches an instance of the portal daemon
to the global filesystem namespace.
The conventional mount point is
.Pa /p .
This command is normally executed by
.Xr mount 8
at boot time.
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl o Ar options
Options are specified with a
.Fl o
flag followed by a comma separated string of options.
See the
.Xr mount 8
man page for possible options and their meanings.
.El
.Pp
The portal daemon provides an
.Em open
service.
Objects opened under the portal mount point are
dynamically created by the portal daemon according
to rules specified in the named configuration file.
Using this mechanism allows descriptors such as sockets
to be made available in the filesystem namespace.
.Pp
The portal daemon works by being passed the full pathname
of the object being opened.
The daemon creates an appropriate descriptor according
to the rules in the configuration file, and then passes the descriptor back
to the calling process as the result of the
.Fn open
system call.
.Sh NAMESPACE
By convention, the portal daemon divides the namespace into sub-namespaces,
each of which handles objects of a particular type.
.Pp
Currently, two sub-namespaces are implemented:
.Pa tcp
and
.Pa fs .
The
.Pa tcp
namespace takes a hostname and a port (slash separated) and
creates an open TCP/IP connection.
The
.Pa fs
namespace opens the named file, starting back at the root directory.
This can be used to provide a controlled escape path from
a chrooted environment.
.Sh "CONFIGURATION FILE"
The configuration file contains a list of rules.
Each rule takes one line and consists of two or more
whitespace separated fields.
A hash
.Pq Sq #
character causes the remainder of a line to be ignored.
Blank lines are ignored.
.Pp
The first field is a pathname prefix to match
against the requested pathname.
If a match is found, the second field
tells the daemon what type of object to create.
Subsequent fields are passed to the creation function.
.Bd -literal
# @(#)portal.conf	5.1 (Berkeley) 7/13/92
tcp/		tcp tcp/
fs/		file fs/
.Ed
.Sh FILES
.Bl -tag -width /p/* -compact
.It Pa /p/*
.El
.Sh SEE ALSO
.Xr mount 2 ,
.Xr fstab 5 ,
.Xr mount 8 ,
.Xr umount 8
.Rs
.%A W. R. Stevens
.%A J. Pendry
.%T "Portals in 4.4BSD"
.%J "USENIX Conference Proceedings"
.%D 1995
.Re
.Sh HISTORY
The
.Nm
utility first appeared in
.Bx 4.4 .
.Sh CAVEATS
This filesystem may not be NFS-exported.