src/stackvma-freebsd.c

   1 /* Determine the virtual memory area of a given address.  FreeBSD version.
   2    Copyright (C) 2002-2003, 2006, 2008  Bruno Haible <bruno@clisp.org>
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software Foundation,
  16    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  17
  18 #include "stackvma.h"
  19 #include <stdio.h>
  20
  21 #include "stackvma-simple.c"
  22 #include "stackvma-rofile.c"
  23
  24 #if HAVE_MINCORE
  25 # define sigsegv_get_vma mincore_get_vma
  26 # define STATIC static
  27 # include "stackvma-mincore.c"
  28 # undef sigsegv_get_vma
  29 #endif
  30
  31 int
  32 sigsegv_get_vma (unsigned long address, struct vma_struct *vma)
  33 {
  34   struct rofile rof;
  35   int c;
  36   /* The stack appears as multiple adjacents segments, therefore we
  37      merge adjacent segments.  */
  38   unsigned long next_start, next_end, curr_start, curr_end;
  39 #if STACK_DIRECTION < 0
  40   unsigned long prev_end;
  41 #endif
  42
  43   /* Open the current process' maps file.  It describes one VMA per line.  */
  44   if (rof_open (&rof, "/proc/curproc/map") < 0)
  45     goto failed;
  46
  47 #if STACK_DIRECTION < 0
  48   prev_end = 0;
  49 #endif
  50   for (curr_start = curr_end = 0; ;)
  51     {
  52       if (!(rof_getchar (&rof) == '0'
  53             && rof_getchar (&rof) == 'x'
  54             && rof_scanf_lx (&rof, &next_start) >= 0))
  55         break;
  56       while (c = rof_peekchar (&rof), c == ' ' || c == '\t')
  57         rof_getchar (&rof);
  58       if (!(rof_getchar (&rof) == '0'
  59             && rof_getchar (&rof) == 'x'
  60             && rof_scanf_lx (&rof, &next_end) >= 0))
  61         break;
  62       while (c = rof_getchar (&rof), c != -1 && c != '\n')
  63         continue;
  64       if (next_start == curr_end)
  65         {
  66           /* Merge adjacent segments.  */
  67           curr_end = next_end;
  68         }
  69       else
  70         {
  71           if (curr_start < curr_end
  72               && address >= curr_start && address <= curr_end-1)
  73             goto found;
  74 #if STACK_DIRECTION < 0
  75           prev_end = curr_end;
  76 #endif
  77           curr_start = next_start; curr_end = next_end;
  78         }
  79     }
  80   if (address >= curr_start && address <= curr_end-1)
  81     found:
  82     {
  83       vma->start = curr_start;
  84       vma->end = curr_end;
  85 #if STACK_DIRECTION < 0
  86       vma->prev_end = prev_end;
  87 #else
  88       if (rof_getchar (&rof) == '0'
  89           && rof_getchar (&rof) == 'x'
  90           && rof_scanf_lx (&rof, &vma->next_start) >= 0)
  91         {
  92           while (c = rof_peekchar (&rof), c == ' ' || c == '\t')
  93             rof_getchar (&rof);
  94           if (rof_getchar (&rof) == '0'
  95               && rof_getchar (&rof) == 'x'
  96               && rof_scanf_lx (&rof, &next_end) >= 0)
  97             ;
  98           else
  99             vma->next_start = 0;
 100         }
 101       else
 102         vma->next_start = 0;
 103 #endif
 104       rof_close (&rof);
 105       vma->is_near_this = simple_is_near_this;
 106       return 0;
 107     }
 108   rof_close (&rof);
 109  failed:
 110 #if HAVE_MINCORE
 111   /* FreeBSD 6.[01] doesn't allow to distinguish unmapped pages from
 112      mapped but swapped-out pages.  See whether it's fixed.  */
 113   if (!is_mapped (0))
 114     /* OK, mincore() appears to work as expected.  */
 115     return mincore_get_vma (address, vma);
 116 #endif
 117   return -1;
 118 }