support/support_become_root.c

   1 /* Acquire root privileges.
   2    Copyright (C) 2016-2017 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    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <support/namespace.h>
  20
  21 #include <sched.h>
  22 #include <stdio.h>
  23 #include <unistd.h>
  24
  25 bool
  26 support_become_root (void)
  27 {
  28 #ifdef CLONE_NEWUSER
  29   if (unshare (CLONE_NEWUSER | CLONE_NEWNS) == 0)
  30     /* Even if we do not have UID zero, we have extended privileges at
  31        this point.  */
  32     return true;
  33 #endif
  34   if (setuid (0) != 0)
  35     {
  36       printf ("warning: could not become root outside namespace (%m)\n");
  37       return false;
  38     }
  39   return true;
  40 }