1.\" Copyright (c) 1989, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" From: @(#)getgrent.3 8.2 (Berkeley) 4/19/94 33.\" $FreeBSD$ 34.\" 35.Dd September 29, 1994 36.Dt GETGRENT 3 37.Os 38.Sh NAME 39.Nm getgrent , 40.Nm getgrnam , 41.Nm getgrgid , 42.Nm setgroupent , 43.\" .Nm setgrfile , 44.Nm setgrent , 45.Nm endgrent 46.Nd group database operations 47.Sh LIBRARY 48.Lb libc 49.Sh SYNOPSIS 50.In grp.h 51.Ft struct group * 52.Fn getgrent void 53.Ft struct group * 54.Fn getgrnam "const char *name" 55.Ft struct group * 56.Fn getgrgid "gid_t gid" 57.Ft int 58.Fn setgroupent "int stayopen" 59.\" .Ft void 60.\" .Fn setgrfile "const char *name" 61.Ft int 62.Fn setgrent void 63.Ft void 64.Fn endgrent void 65.Sh DESCRIPTION 66These functions operate on the group database file 67.Pa /etc/group 68which is described 69in 70.Xr group 5 . 71Each line of the database is defined by the structure 72.Vt group 73found in the include 74file 75.Aq Pa grp.h : 76.Bd -literal -offset indent 77struct group { 78 char *gr_name; /* group name */ 79 char *gr_passwd; /* group password */ 80 gid_t gr_gid; /* group id */ 81 char **gr_mem; /* group members */ 82}; 83.Ed 84.Pp 85The functions 86.Fn getgrnam 87and 88.Fn getgrgid 89search the group database for the given group name pointed to by 90.Fa name 91or the group id pointed to by 92.Fa gid , 93respectively, returning the first one encountered. Identical group 94names or group gids may result in undefined behavior. 95.Pp 96The 97.Fn getgrent 98function 99sequentially reads the group database and is intended for programs 100that wish to step through the complete list of groups. 101.Pp 102All three routines will open the group file for reading, if necessary. 103.Pp 104The 105.Fn setgroupent 106function 107opens the file, or rewinds it if it is already open. If 108.Fa stayopen 109is non-zero, file descriptors are left open, significantly speeding 110functions subsequent calls. This functionality is unnecessary for 111.Fn getgrent 112as it doesn't close its file descriptors by default. It should also 113be noted that it is dangerous for long-running programs to use this 114functionality as the group file may be updated. 115.Pp 116The 117.Fn setgrent 118function 119is identical to 120.Fn setgroupent 121with an argument of zero. 122.Pp 123The 124.Fn endgrent 125function 126closes any open files. 127.Sh RETURN VALUES 128The functions 129.Fn getgrent , 130.Fn getgrnam , 131and 132.Fn getgrgid , 133return a pointer to the group entry if successful; if end-of-file 134is reached or an error occurs a null pointer is returned. 135The functions 136.Fn setgroupent 137and 138.Fn setgrent 139return the value 1 if successful, otherwise the value 1400 is returned. 141The functions 142.Fn endgrent 143and 144.Fn setgrfile 145have no return value. 146.Sh FILES 147.Bl -tag -width /etc/group -compact 148.It Pa /etc/group 149group database file 150.El 151.Sh SEE ALSO 152.Xr getpwent 3 , 153.Xr group 5 , 154.Xr nsswitch.conf 5 , 155.Xr yp 8 156.Sh HISTORY 157The functions 158.Fn endgrent , 159.Fn getgrent , 160.Fn getgrnam , 161.Fn getgrgid , 162and 163.Fn setgrent 164appeared in 165.At v7 . 166The functions 167.Fn setgrfile 168and 169.Fn setgroupent 170appeared in 171.Bx 4.3 Reno . 172.Sh COMPATIBILITY 173The historic function 174.Fn setgrfile , 175which allowed the specification of alternate password databases, has 176been deprecated and is no longer available. 177.Sh BUGS 178The functions 179.Fn getgrent , 180.Fn getgrnam , 181.Fn getgrgid , 182.Fn setgroupent 183and 184.Fn setgrent 185leave their results in an internal static object and return 186a pointer to that object. 187Subsequent calls to 188the same function 189will modify the same object. 190.Pp 191The functions 192.Fn getgrent , 193.Fn endgrent , 194.Fn setgroupent , 195and 196.Fn setgrent 197are fairly useless in a networked environment and should be 198avoided, if possible. 199The 200.Fn getgrent 201function 202makes no attempt to suppress duplicate information if multiple 203sources are specified in 204.Xr nsswitch.conf 5 . 205