NetBSD/lib/libc/gen/getgrouplist.3

.\"	$NetBSD: getgrouplist.3,v 1.13 2005/01/06 15:29:35 lukem Exp $
.\"
.\" Copyright (c) 2005 The NetBSD Foundation, Inc.
.\" All rights reserved.
.\"
.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Luke Mewburn.
.\"
.\" 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.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"        This product includes software developed by the NetBSD
.\"        Foundation, Inc. and its contributors.
.\" 4. Neither the name of The NetBSD Foundation nor the names of its
.\"    contributors may be used to endorse or promote products derived
.\"    from this software without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
.\" ``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 FOUNDATION OR CONTRIBUTORS
.\" 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.
.\"
.\" Copyright (c) 1991, 1993
.\"	The Regents of the University of California.  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.
.\" 3. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
.\"
.\"     @(#)getgrouplist.3	8.1 (Berkeley) 6/9/93
.\"
.Dd January 6, 2005
.Dt GETGROUPLIST 3
.Os
.Sh NAME
.Nm getgrouplist ,
.Nm getgroupmembership ,
.Nd calculate group access list
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In unistd.h
.Ft int
.Fn getgrouplist "const char *name" "gid_t basegid" "gid_t *groups" "int *ngroups"
.Ft int
.Fn getgroupmembership "const char *name" "gid_t basegid" "gid_t *groups" "int maxgrp" "int *ngroups"
.Sh DESCRIPTION
The
.Fn getgrouplist
and
.Fn getgroupmembership
functions read through the group database and calculate
the group access list for the user specified in
.Fa name .
The
.Fa basegid
is automatically included in the groups list.
Typically this value is given as
the group number from the password database.
.Pp
The resulting group list is returned in the integer array pointed to by
.Fa groups .
.Pp
For
.Fn getgrouplist ,
the caller specifies the size of the
.Fa groups
array in the integer pointed to by
.Fa ngroups .
.Pp
For
.Fn getgroupmembership ,
the caller specifies the size of the
.Fa groups
array in
.Fa maxgrp .
.Pp
The actual number of groups found is returned in
.Fa ngroups .
.Pp
Duplicate group ids will be suppressed from the result.
.Sh RETURN VALUES
The
.Fn getgrouplist
and
.Fn getgroupmembership
functions
return 0 if successful, and
return \-1 if the size of the group list is too small to
hold all the user's groups.
In the latter case, the
.Fa groups
array will be filled with as many groups as will fit and
.Fa ngroups
will contain the total number of groups found.
.Sh FILES
.Bl -tag -width /etc/group -compact
.It Pa /etc/group
group membership list
.El
.Sh SEE ALSO
.Xr setgroups 2 ,
.Xr initgroups 3 ,
.Xr group 5
.Sh HISTORY
The
.Fn getgrouplist
function first appeared in
.Bx 4.4 .
The
.Fn getgroupmembership
function first appeared in
.Nx 3.0
to address an API deficiency in
.Fn getgrouplist .
.Sh BUGS
The
.Fn getgrouplist
function
uses the routines based on
.Xr getgrent 3 .
If the invoking program uses any of these routines,
the group structure will
be overwritten in the call to
.Fn getgrouplist .