/* Stack executability handling for GNU dynamic linker.  Linux version.

   Copyright (C) 2003-2018 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 <ldsodefs.h>

#include <sys/mman.h>

#include <errno.h>

#include <libintl.h>

#include <stdbool.h>

#include <stackinfo.h>

#include <sysdep.h>

extern int __stack_prot attribute_relro attribute_hidden;

int

_dl_make_stack_executable (void **stack_endp)

{

  /* This gives us the highest/lowest page that needs to be changed.  */

  uintptr_t page = ((uintptr_t) *stack_endp

		    & -(intptr_t) GLRO(dl_pagesize));

  int result = 0;

  if (__builtin_expect (__mprotect ((void *) page, GLRO(dl_pagesize),

				    __stack_prot) == 0, 1))

    goto return_success;

  result = errno;

  goto out;

 return_success:

  /* Clear the address.  */

  *stack_endp = NULL;

  /* Remember that we changed the permission.  */

  GL(dl_stack_flags) |= PF_X;

 out:

#ifdef check_consistency

  check_consistency ();

#endif

  return result;

}

rtld_hidden_def (_dl_make_stack_executable)