sysdeps/generic/bp-start.h

   1 /* Bounded-pointer checking macros for C.
   2    Copyright (C) 2000 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Greg McGary <greg@mcgary.org>
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20
  21 #if __BOUNDED_POINTERS__
  22
  23   /* The command-line arg vector and environment vector come to us from
  24      the OS as an unbounded pointer to an array of unbounded strings.
  25      The user's main expects argv and __environ to be bounded pointers
  26      to arrays of bounded strings.  */
  27 # define INIT_ARGV_and_ENVIRON \
  28   do {                                                                        \
  29     int envc;                                                                 \
  30     for (envc = 0; *ubp_ev; ubp_ev++, envc++)                                 \
  31       ;                                                                       \
  32     ubp_ev -= envc;                                                           \
  33                                                                               \
  34     /* GKM FIXME: we could save some space by allocating only enough for      \
  35        the additional low & high words, and destructively rewriting           \
  36        argv in place.  */                                                     \
  37     __ptrvalue (argv) = __ptrlow (argv)                                       \
  38       = alloca ((argc + envc + 2) * sizeof (*argv));                          \
  39     __ptrhigh (argv) = __ptrvalue (argv) + argc + 1;                          \
  40     __ptrvalue (__environ) = __ptrlow (__environ) = __ptrhigh (argv);         \
  41     __ptrhigh (__environ) = __ptrvalue (__environ) + envc + 1;                \
  42     boundify_vector (__environ, ubp_ev);                                      \
  43     boundify_vector (argv, ubp_av);                                           \
  44   } while (0)
  45
  46
  47 /* Copy an unbounded vector of unbounded strings into a bounded
  48    counterpart.  */
  49
  50 static void
  51 boundify_vector (char **dest, char *__unbounded *__unbounded src)
  52 {
  53   char *__unbounded s;
  54   for (; *src; src++, dest++)
  55     {
  56       __ptrvalue (*dest) = __ptrlow (*dest) = *src;
  57       __ptrhigh (*dest) = src[1];
  58     }
  59   *dest = 0;
  60   /* The OS lays out strings contiguously in vector order,
  61      so  */
  62   for (s = __ptrvalue (dest[-1]); *s; s++)
  63     ;
  64   __ptrhigh (dest[-1]) = ++s;
  65 }
  66
  67 #else
  68
  69 # define INIT_ARGV_and_ENVIRON __environ = ubp_ev
  70
  71 #endif