1/* Enter a mount namespace.
2 Copyright (C) 2017-2020 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <support/namespace.h>
20
21#include <sched.h>
22#include <stdio.h>
23#ifdef CLONE_NEWNS
24# include <sys/mount.h>
25#endif /* CLONE_NEWNS */
26
27bool
28support_enter_mount_namespace (void)
29{
30#ifdef CLONE_NEWNS
31 if (unshare (CLONE_NEWNS) == 0)
32 {
33 /* On some systems, / is marked as MS_SHARED, which means that
34 mounts within the namespace leak to the rest of the system,
35 which is not what we want. */
36 if (mount ("none", "/", NULL, MS_REC | MS_PRIVATE, NULL) != 0)
37 {
38 printf ("warning: making the mount namespace private failed: %m\n");
39 return false;
40 }
41 return true;
42 }
43 else
44 printf ("warning: unshare (CLONE_NEWNS) failed: %m\n");
45#endif /* CLONE_NEWNS */
46 return false;
47}
48