1 files changed, 50 insertions, 0 deletions
diff --git a/posix/group_member.c b/posix/group_member.c
new file mode 100644
index 0000000000..7bd9c46ba2
--- /dev/null
+++ b/posix/group_member.c
@@ -0,0 +1,50 @@
+/* `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)