/* Enter a mount namespace.

   Copyright (C) 2017-2018 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, see

   <http://www.gnu.org/licenses/>.  */

#include <support/namespace.h>

#include <sched.h>

#include <stdio.h>

#ifdef CLONE_NEWNS

# include <sys/mount.h>

#endif /* CLONE_NEWNS */

bool

support_enter_mount_namespace (void)

{

#ifdef CLONE_NEWNS

  if (unshare (CLONE_NEWNS) == 0)

    {

      /* On some systems, / is marked as MS_SHARED, which means that

         mounts within the namespace leak to the rest of the system,

         which is not what we want.  */

      if (mount ("none", "/", NULL, MS_REC | MS_PRIVATE, NULL) != 0)

        {

          printf ("warning: making the mount namespace private failed: %m\n");

          return false;

        }

      return true;

    }

  else

    printf ("warning: unshare (CLONE_NEWNS) failed: %m\n");

#endif /* CLONE_NEWNS */

  return false;

}