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.\"
.\" Copyright (c) 2006 Ceri Davies <ceri@FreeBSD.org>
.\"
.\" All rights reserved.
.\"
.\" 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.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``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 DEVELOPERS 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.
.\"
.\" $FreeBSD$
.\"
.Dd November 19, 2006
.Dt CR_CANSEE 9
.Os
.Sh NAME
.Nm cr_cansee
.Nd "determine visibility of objects given their user credentials"
.Sh SYNOPSIS
.In sys/param.h
.In sys/systm.h
.In sys/ucred.h
.Ft int
.Fn cr_cansee "struct ucred *u1" "struct ucred *u2"
.Sh DESCRIPTION
This function determines the visibility of objects in the
kernel based on the real user IDs and group IDs in the credentials
.Fa u1
and
.Fa u2
associated with them.
.Pp
The visibility of objects is influenced by the
.Xr sysctl 8
variables
.Va security.bsd.see_other_gids
and
.Va security.bsd.see_other_uids ,
as per the description in
.Xr cr_seeothergids 9
and
.Xr cr_seeotheruids 9
respectively.
.Sh RETURN VALUES
This function returns zero if the object with credential
.Fa u1
can
.Dq see
the object with credential
.Fa u2 ,
or
.Er ESRCH
otherwise.
.Sh ERRORS
.Bl -tag -width Er
.It Bq Er ESRCH
The object with credential
.Fa u1
cannot
.Dq see
the object with credential
.Fa u2 .
.It Bq Er ESRCH
The object with credential
.Fa u1
has been jailed and the object with credential
.Fa u2
does not belong to the same jail as
.Fa u1 .
.It Bq Er ESRCH
The MAC subsystem denied visibility.
.El
.Sh SEE ALSO
.Xr cr_seeothergids 9 ,
.Xr cr_seeotheruids 9 ,
.Xr mac 9 ,
.Xr p_cansee 9
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