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MOUNT_PORTALFS(8)	  BSD System Manager's Manual	     MOUNT_PORTALFS(8)

     mount_portalfs -- mount the portal	daemon

     mount_portalfs [-o	options] /etc/portal.conf mount_point

     The mount_portalfs	utility	attaches an instance of	the portal daemon to
     the global	file system namespace.	The conventional mount point is	/p.
     This command is normally executed by mount(8) at boot time.

     The options are as	follows:

     -o	     Options are specified with	a -o flag followed by a	comma sepa-
	     rated string of options.  See the mount(8)	man page for possible
	     options and their meanings.

     The portal	daemon provides	an 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 file sys-
     tem namespace.

     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 open system call.

     By	convention, the	portal daemon divides the namespace into sub-name-
     spaces, each of which handles objects of a	particular type.

     The following sub-namespaces are currently	implemented: fs, pipe, tcp,
     and tcplisten.

     The fs namespace opens the	named file, starting back at the root direc-
     tory.  This can be	used to	provide	a controlled escape path from a	ch-
     rooted environment.

     The pipe namespace	executes the named command, starting back at the root
     directory.	 The command's arguments can be	provided after the command's
     name, by separating them with spaces or tabs.  Files opened for reading
     in	the pipe namespace will	receive	their input from the command's stan-
     dard output; files	opened for writing will	send the data of write opera-
     tions to the command's standard input.

     The tcp namespace takes a slash separated hostname	and a port and creates
     an	open TCP/IP connection.

     The tcplisten namespace takes a slash separated hostname and port and
     creates a TCP/IP socket bound to the given	hostname-port pair.  The host-
     name may be specified as "ANY" to allow any other host to connect to the
     socket.  A	port number of 0 will dynamically allocate a port, this	can be
     discovered	by calling getsockname(2) with the returned file descriptor.
     Privileged	ports can only be bound	to by the super-user.

     The configuration file contains a list of rules.  Each rule takes one
     line and consists of two or more whitespace separated fields.  A hash
     (``#'') character causes the remainder of a line to be ignored.  Blank
     lines are ignored.

     The first field is	a pathname prefix to match against the requested path-
     name.  If a match is found, the second field tells	the daemon what	type
     of	object to create.  Subsequent fields are passed	to the creation	func-

     # @(#)portal.conf	     5.1 (Berkeley) 7/13/92
     tcplisten/	     tcplisten tcplisten/
     tcp/	     tcp tcp/
     fs/	     file fs/
     pipe/	     pipe pipe/


     Display the greeting of the FreeBSD SMTP server.

	   head	-1 /p/tcp/

     Implement a (single-threaded) echo	server:

	   while :
	       (exec 3<>/p/tcplisten/ANY/echo && cat -u	<&3 >&3)

     Gather data from two sources.  Verify that	two remote files are identi-

	   diff	-q '/p/pipe/usr/bin/fetch -o - \' \
	       '/p/pipe/usr/bin/fetch -o - \'

     Scatter data to two sinks.	 Record	a remote CD ISO	image and calculate
     its checksum:

	   fetch -o - |
	   tee '/p/pipe/usr/local/bin/cdrecord -' |

     Create an XML view	of the password	file:

	   ln -s '/p/pipe/usr/local/bin/passwd2xml /etc/passwd'	\

     mount(2), unmount(2), fstab(5), mount(8)

     W.	Richard	Stevens	and Jan-Simon Pendry, "Portals in 4.4BSD", USENIX 1995
     Technical Conference Proceedings, Peter Honeyman, Berkeley, CA.

     This file system may not be NFS-exported.

     The mount_portalfs	utility	first appeared in 4.4BSD.

BSD				March 11, 2005				   BSD


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