Change setgroups to affect all the threads in the process.

sysdeps/unix/sysv/linux/setgroups.c

@@ -0,0 +1,37 @@
+/* Copyright (C) 1997,1998,2000,2002,2004,2006,2011
+   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 <errno.h>
+#include <grp.h>
+#include <setxid.h>
+#include <sysdep.h>
+
+
+/* Set the group set for the current user to GROUPS (N of them).  For
+   Linux we must convert the array of groups into the format that the
+   kernel expects.  */
+int
+setgroups (size_t n, const gid_t *groups)
+{
+#ifdef __NR_setgroups32
+# error "wrong setgroups.c file used"
+#endif
+  return INLINE_SETXID_SYSCALL (setgroups, 2, n, groups);
+}
+libc_hidden_def (setgroups)