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VMOD_UNIX(3)							  VMOD_UNIX(3)

       vmod_unix - Utilities for Unix domain sockets

	  import unix [as name]	[from "path"]

	  STRING user()

	  STRING group()

	  INT uid()

	  INT gid()

       This  VMOD  provides  information  about	 the  credentials  of the peer
       process (user and group of the process owner) that is  connected	 to  a
       Varnish listener	via a Unix domain socket, if the platform supports it.


	  import unix;

	  sub vcl_recv {
		# Return "403 Forbidden" if the	connected peer is
		# not running as the user "trusteduser".
		if (unix.user()	!= "trusteduser") {
			return(	synth(403) );

		# Require the connected	peer to	run in the group
		# "trustedgroup".
		if ( != "trustedgroup") {
			return(	synth(403) );

		# Require the connected	peer to	run under a specific numeric
		# user id.
		if (unix.uid() != 4711)	{
			return(	synth(403) );

		# Require the connected	peer to	run under a numeric group id.
		if (unix.gid() != 815) {
			return(	synth(403) );

       Obtaining  the peer credentials is possible on a	platform that supports
       one of the following:

       o getpeereid(3) (such as	FreeBSD	and other BSD-derived systems)

       o the socket option SO_PEERCRED for getsockopt(2) (Linux)

       o getpeerucred(3C) (SunOS and descendants)

       On SunOS	and friends, the PRIV_PROC_INFO	privilege set is added to  the
       Varnish child process while the VMOD is loaded, see setppriv(2).

       On  most	 platforms,  the value returned	is the effective user or group
       that was	valid when the peer process initiated the connection.

   STRING user()
       Return the user name of the peer	process	owner.

   STRING group()
       Return the group	name of	the peer process owner.

   INT uid()
       Return the numeric user id of the peer process owner.

   INT gid()
       Return the numeric group	id of the peer process owner.

       All functions in	this VMOD are subject to the following constraints:

       o None of them may be called in vcl_init{} or  vcl_fini{}.  If  one  of
	 them is called	in vcl_init{}, then the	VCL program will fail to load,
	 with an error message from the	VMOD.

       o If called on a	platform that is not supported,	then  VCL  failure  is
	 invoked.  An  error message is	written	to the log (with the VCL_Error
	 tag), and for all VCL subroutines except for vcl_synth{}, control  is
	 directed  immediately to vcl_synth{}, with the	response status	set to
	 503 and the reason string set to "VCL failed".

	 If  the  failure  occurs  during  vcl_synth{},	 then  vcl_synth{}  is
	 aborted, and the the response line "503 VCL failed" is	sent.

       o If  the  current  listener is not a Unix domain socket, or if the at-
	 tempt to read credentials fails, then a VCL_Error message is  written
	 to  the  log. The STRING functions (unix.user() and re-
	 turn NULL, while the INT functions (unix.uid()	and unix.gid())	return

       o varnishd(1)

       o vcl(7)

       o getpeereid(3)

       o getsockopt(2)

       o getpeerucred(3C)

       o setppriv(2)

	  This document	is licensed under the same conditions as Varnish itself.
	  See LICENSE for details.

	  Authors: Geoffrey Simmons <>



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