tal-debug.c

/* TMP_ALLOC routines for debugging.

Copyright 2000, 2001, 2004 Free Software Foundation, Inc.

This file is part of the GNU MP Library.

The GNU MP 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 3 of the License, or (at your
option) any later version.

The GNU MP 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 MP Library.  If not, see http://www.gnu.org/licenses/.  */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "gmp.h"
#include "gmp-impl.h"


/* This method aims to help a malloc debugger find problems.  A linked list
   of allocated block is kept for TMP_FREE to release.  This is reentrant
   and thread safe.

   Each TMP_ALLOC is a separate malloced block, so redzones or sentinels
   applied by a malloc debugger either above or below can guard against
   accesses outside the allocated area.

   A marker is a "struct tmp_debug_t *" so that TMP_DECL can initialize it
   to NULL and we can detect TMP_ALLOC without TMP_MARK.

   It will work to realloc an MPZ_TMP_INIT variable, but when TMP_FREE comes
   to release the memory it will have the old size, thereby triggering an
   error from tests/memory.c.

   Possibilities:

   It'd be possible to keep a global list of active "struct tmp_debug_t"
   records, so at the end of a program any TMP leaks could be printed.  But
   if only a couple of routines are under test at any one time then the
   likely culprit should be easy enough to spot.  */


void
__gmp_tmp_debug_mark (const char *file, int line,
                      struct tmp_debug_t **markp, struct tmp_debug_t *mark,
                      const char *decl_name, const char *mark_name)
{
  if (strcmp (mark_name, decl_name) != 0)
    {
      __gmp_assert_header (file, line);
      fprintf (stderr, "GNU MP: TMP_MARK(%s) but TMP_DECL(%s) is in scope\n",
               mark_name, decl_name);
      abort ();
    }

  if (*markp != NULL)
    {
      __gmp_assert_header (file, line);
      fprintf (stderr, "GNU MP: Repeat of TMP_MARK(%s)\n", mark_name);
      if (mark->file != NULL && mark->file[0] != '\0' && mark->line != -1)
        {
          __gmp_assert_header (mark->file, mark->line);
          fprintf (stderr, "previous was here\n");
        }
      abort ();
    }

  *markp = mark;
  mark->file = file;
  mark->line = line;
  mark->list = NULL;
}

void *
__gmp_tmp_debug_alloc (const char *file, int line, int dummy,
                       struct tmp_debug_t **markp,
                       const char *decl_name, size_t size)
{
  struct tmp_debug_t        *mark = *markp;
  struct tmp_debug_entry_t  *p;

  ASSERT_ALWAYS (size >= 1);

  if (mark == NULL)
    {
      __gmp_assert_header (file, line);
      fprintf (stderr, "GNU MP: TMP_ALLOC without TMP_MARK(%s)\n", decl_name);
      abort ();
    }

  p = __GMP_ALLOCATE_FUNC_TYPE (1, struct tmp_debug_entry_t);
  p->size = size;
  p->block = (*__gmp_allocate_func) (size);
  p->next = mark->list;
  mark->list = p;
  return p->block;
}

void
__gmp_tmp_debug_free (const char *file, int line, int dummy,
                      struct tmp_debug_t **markp,
                      const char *decl_name, const char *free_name)
{
  struct tmp_debug_t        *mark = *markp;
  struct tmp_debug_entry_t  *p, *next;

  if (mark == NULL)
    {
      __gmp_assert_header (file, line);
      fprintf (stderr, "GNU MP: TMP_FREE(%s) without TMP_MARK(%s)\n",
               free_name, decl_name);
      abort ();
    }

  if (strcmp (free_name, decl_name) != 0)
    {
      __gmp_assert_header (file, line);
      fprintf (stderr, "GNU MP: TMP_FREE(%s) when TMP_DECL(%s) is in scope\n",
               free_name, decl_name);
      abort ();
    }

  p = mark->list;
  while (p != NULL)
    {
      next = p->next;
      (*__gmp_free_func) (p->block, p->size);
      __GMP_FREE_FUNC_TYPE (p, 1, struct tmp_debug_entry_t);
      p = next;
    }

  *markp = NULL;
}