1.\" 2.\" Copyright (c) 2003 Joseph Koshy <jkoshy@freebsd.org> 3.\" Copyright (c) 2006 Ceri Davies <ceri@FreeBSD.org> 4.\" 5.\" All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR 17.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT, 20.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26.\" 27.\" $FreeBSD$ 28.\" 29.Dd November 19, 2006 30.Os 31.Dt P_CANSEE 9 32.Sh NAME 33.Nm p_cansee 34.Nd determine visibility of a process 35.Sh SYNOPSIS 36.In sys/param.h 37.In sys/proc.h 38.Ft int 39.Fn p_cansee "struct thread *td" "struct proc *p" 40.Sh DESCRIPTION 41This function can be used to determine if a given process 42.Fa p 43is visible to the thread 44.Fa td , 45where the notion of 46.Dq visibility 47may be read as 48.Dq "awareness of existence" . 49.Pp 50The function is implemented using 51.Xr cr_cansee 9 , 52and the dependencies on 53.Xr sysctl 8 54variables documented in the 55.Xr cr_cansee 9 56manual page apply. 57.Sh RETURN VALUES 58The 59.Fn p_cansee 60function 61returns 62.Li 0 63if the process denoted by 64.Fa p 65is visible by thread 66.Fa td , 67or a non-zero error return value otherwise. 68.Sh ERRORS 69.Bl -tag -width Er 70.It Bq Er ESRCH 71Process 72.Fa p 73is not visible to thread 74.Fa td 75as determined by 76.Xr cr_cansee 9 . 77.It Bq Er ESRCH 78Thread 79.Fa td 80has been jailed and process 81.Fa p 82does not belong to the same jail as 83.Fa td . 84.It Bq Er ESRCH 85The MAC subsystem denied visibility. 86.El 87.Sh SEE ALSO 88.Xr jail 2 , 89.Xr sysctl 8 , 90.Xr cr_cansee 9 , 91.Xr mac 9 , 92.Xr p_candebug 9 , 93.Xr prison_check 9 94