1 /* Copyright (C) 1989, 1991, 1993, 1996, 1997 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Library General Public License as
6 published by the Free Software Foundation; either version 2 of the
7 License, or (at your option) any later version.
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Library General Public License for more details.
14 You should have received a copy of the GNU Library General Public
15 License along with the GNU C Library; see the file COPYING.LIB. If not,
16 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 Boston, MA 02111-1307, USA. */
25 #include <sys/types.h>
28 /* Initialize the group set for the current user
29 by reading the group database and using all groups
30 of which USER is a member. Also include GROUP. */
32 initgroups (user, group)
36 #if defined NGROUPS_MAX && NGROUPS_MAX == 0
38 /* No extra groups allowed. */
43 struct group grpbuf, *g;
44 size_t buflen = sysconf (_SC_GETPW_R_SIZE_MAX);
51 # define limit NGROUPS_MAX
55 long int limit = sysconf (_SC_NGROUPS_MAX);
60 /* No fixed limit on groups. Pick a starting buffer size. */
64 groups = __alloca (ngroups * sizeof *groups);
65 tmpbuf = __alloca (buflen);
74 while ((status = __getgrent_r (&grpbuf, tmpbuf, buflen, &g)) != 0
78 tmpbuf = __alloca (buflen);
81 if (status == 0 && g->gr_gid != group)
85 for (m = g->gr_mem; *m != NULL; ++m)
86 if (strcmp (*m, user) == 0)
88 /* Matches user. Insert this group. */
89 if (n == ngroups && limit <= 0)
91 /* Need a bigger buffer. */
93 newgrp = __alloca (ngroups * 2 * sizeof *groups);
94 groups = memcpy (newgrp, groups, ngroups * sizeof *groups);
98 groups[n++] = g->gr_gid;
101 /* Can't take any more groups; stop searching. */
113 return setgroups (n, groups);