1.\" 2.\" Copyright (C) 2001 Chad David <davidc@acns.ab.ca>. All rights reserved. 3.\" Copyright (C) 2023 Olivier Certner <olce.freebsd@certner.fr> 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice(s), this list of conditions and the following disclaimer as 10.\" the first lines of this file unmodified other than the possible 11.\" addition of one or more copyright notices. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice(s), 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 COPYRIGHT HOLDER(S) ``AS IS'' AND ANY 17.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 18.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 19.\" DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY 20.\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 21.\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 22.\" SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 23.\" CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH 26.\" DAMAGE. 27.\" 28.Dd October 31, 2024 29.Dt GROUPMEMBER 9 30.Os 31.Sh NAME 32.Nm groupmember 33.Nd checks if credentials mandate some group membership 34.Sh SYNOPSIS 35.In sys/param.h 36.In sys/ucred.h 37.Ft bool 38.Fn groupmember "gid_t gid" "const struct ucred *cred" 39.Ft bool 40.Fn realgroupmember "gid_t gid" "const struct ucred *cred" 41.Sh DESCRIPTION 42The 43.Fn groupmember 44function checks if credentials 45.Fa cred 46indicate that the associated subject or object is a member of the group 47designated by the group ID 48.Fa gid . 49.Pp 50Considered groups in 51.Fa cred 52are the effective and supplementary groups. 53The real group is not taken into account. 54.Pp 55Function 56.Fn realgroupmember 57works the same except that it considers instead the real and supplementary 58groups, and not the effective one. 59.Sh RETURN VALUES 60The 61.Fn groupmember 62and 63.Fn realgroupmember 64functions return 65.Dv true 66if the given credentials indicate membership of the group 67.Fa gid , 68or 69.Dv false 70otherwise. 71.Sh SEE ALSO 72.Xr getgroups 2 , 73.Xr setgroups 2 74.Sh AUTHORS 75This manual page was initially written by 76.An -nosplit 77.An Chad David Aq Mt davidc@acns.ab.ca 78and was revised by 79.An Olivier Certner Aq Mt olce.freebsd@certner.fr . 80