1.\" $NetBSD: getgrouplist.3,v 1.8 2002/02/07 07:00:12 ross Exp $ 2.\" 3.\" Copyright (c) 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)getgrouplist.3 8.1 (Berkeley) 6/9/93 35.\" 36.Dd April 25, 1999 37.Dt GETGROUPLIST 3 38.Os 39.Sh NAME 40.Nm getgrouplist 41.Nd calculate group access list 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.Fd #include \*[Lt]unistd.h\*[Gt] 46.Ft int 47.Fn getgrouplist "const char *name" "gid_t basegid" "gid_t *groups" "int *ngroups" 48.Sh DESCRIPTION 49The 50.Fn getgrouplist 51function reads through the group database and calculates 52the group access list for the user specified in 53.Fa name . 54The 55.Fa basegid 56is automatically included in the groups list. 57Typically this value is given as 58the group number from the password database. 59.Pp 60The resulting group list is returned in the integer array pointed to by 61.Fa groups . 62The caller specifies the size of the 63.Fa groups 64array in the integer pointed to by 65.Fa ngroups ; 66the actual number of groups found is returned in 67.Fa ngroups . 68.Pp 69Duplicate group ids will be suppressed from the result. 70.Sh RETURN VALUES 71The 72.Fn getgrouplist 73function 74returns \-1 if the size of the group list is too small to 75hold all the user's groups. 76Here, the group array will be filled with as many groups as will fit. 77.Sh FILES 78.Bl -tag -width /etc/group -compact 79.It Pa /etc/group 80group membership list 81.El 82.Sh SEE ALSO 83.Xr setgroups 2 , 84.Xr initgroups 3 85.Sh HISTORY 86The 87.Fn getgrouplist 88function first appeared in 89.Bx 4.4 . 90.Sh BUGS 91The 92.Fn getgrouplist 93function 94uses the routines based on 95.Xr getgrent 3 . 96If the invoking program uses any of these routines, 97the group structure will 98be overwritten in the call to 99.Fn getgrouplist . 100.Pp 101In the case where the group array is too small and duplicate gids 102have been suppressed, the returned 103.Fa ngroups 104will be too large by a factor of the difference between the given 105size and the number of matches. 106This is not considered to be a major problem, since it's still going 107to be a smaller figure than when duplicates were not suppressed. 108