gdb/nat/linux-personality.c

   1 /* Disable address space randomization based on inferior personality.
   2
   3    Copyright (C) 2008-2021 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "gdbsupport/common-defs.h"
  21 #include "nat/linux-personality.h"
  22
  23 #ifdef HAVE_PERSONALITY
  24 # include <sys/personality.h>
  25 # if !HAVE_DECL_ADDR_NO_RANDOMIZE
  26 #  define ADDR_NO_RANDOMIZE 0x0040000
  27 # endif /* ! HAVE_DECL_ADDR_NO_RANDOMIZE */
  28 #endif /* HAVE_PERSONALITY */
  29
  30 /* See comment on nat/linux-personality.h.  */
  31
  32 maybe_disable_address_space_randomization::
  33 maybe_disable_address_space_randomization (int disable_randomization)
  34   : m_personality_set (false),
  35     m_personality_orig (0)
  36 {
  37 #ifdef HAVE_PERSONALITY
  38   if (disable_randomization)
  39     {
  40       errno = 0;
  41       m_personality_orig = personality (0xffffffff);
  42       if (errno == 0 && !(m_personality_orig & ADDR_NO_RANDOMIZE))
  43         {
  44           m_personality_set = true;
  45           personality (m_personality_orig | ADDR_NO_RANDOMIZE);
  46         }
  47       if (errno != 0 || (m_personality_set
  48                          && !(personality (0xffffffff) & ADDR_NO_RANDOMIZE)))
  49         warning (_("Error disabling address space randomization: %s"),
  50                  safe_strerror (errno));
  51     }
  52 #endif /* HAVE_PERSONALITY */
  53 }
  54
  55 maybe_disable_address_space_randomization::
  56 ~maybe_disable_address_space_randomization ()
  57 {
  58 #ifdef HAVE_PERSONALITY
  59
  60   if (m_personality_set)
  61     {
  62       errno = 0;
  63       personality (m_personality_orig);
  64       if (errno != 0)
  65         warning (_("Error restoring address space randomization: %s"),
  66                  safe_strerror (errno));
  67     }
  68 #endif /* HAVE_PERSONALITY */
  69 }