glibc/posix/group_member.c

51 lines
1.4 KiB
C

/* `group_member' -- test if process is in a given group.
Copyright (C) 1995, 1997, 2002 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>
#include <limits.h>
#ifndef NGROUPS_MAX
#define NGROUPS_MAX 16 /* First guess. */
#endif
int
__group_member (gid)
gid_t gid;
{
int n, size;
gid_t *groups;
size = NGROUPS_MAX;
do
{
groups = __alloca (size * sizeof *groups);
n = __getgroups (size, groups);
size *= 2;
} while (n == size / 2);
while (n >= 0)
if (groups[n--] == gid)
return 1;
return 0;
}
weak_alias (__group_member, group_member)