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/* Standard debugging hooks for `malloc'.
Copyright 1990 Free Software Foundation
Written May 1989 by Mike Haertel.
The author may be reached (Email) at the address mike@ai.mit.edu,
or (US mail) as Mike Haertel c/o Free Software Foundation.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "ansidecl.h"
#include <stdlib.h>
#include "gmalloc.h"
/* Old hook values. */
static void EXFUN((*old_free_hook), (PTR ptr));
static PTR EXFUN((*old_malloc_hook), (size_t size));
static PTR EXFUN((*old_realloc_hook), (PTR ptr, size_t size));
/* Function to call when something awful happens. */
static void EXFUN((*abortfunc), (void)) = abort;
/* Arbitrary magical numbers. */
#define MAGICWORD 0xfedabeeb
#define MAGICBYTE ((char) 0xd7)
struct hdr
{
size_t size; /* Exact size requested by user. */
unsigned int magic; /* Magic number to check header integrity. */
};
static void
DEFUN(checkhdr, (hdr), CONST struct hdr *hdr)
{
if (hdr->magic != MAGICWORD || ((char *) &hdr[1])[hdr->size] != MAGICBYTE)
(*abortfunc)();
}
static void
DEFUN(freehook, (ptr), PTR ptr)
{
struct hdr *hdr = ((struct hdr *) ptr) - 1;
checkhdr(hdr);
hdr->magic = 0;
__free_hook = old_free_hook;
free(hdr);
__free_hook = freehook;
}
static PTR
DEFUN(mallochook, (size), size_t size)
{
struct hdr *hdr;
__malloc_hook = old_malloc_hook;
hdr = (struct hdr *) malloc(sizeof(struct hdr) + size + 1);
__malloc_hook = mallochook;
if (hdr == NULL)
return NULL;
hdr->size = size;
hdr->magic = MAGICWORD;
((char *) &hdr[1])[size] = MAGICBYTE;
return (PTR) (hdr + 1);
}
static PTR
DEFUN(reallochook, (ptr, size), PTR ptr AND size_t size)
{
struct hdr *hdr = ((struct hdr *) ptr) - 1;
checkhdr(hdr);
__free_hook = old_free_hook;
__malloc_hook = old_malloc_hook;
__realloc_hook = old_realloc_hook;
hdr = (struct hdr *) realloc((PTR) hdr, sizeof(struct hdr) + size + 1);
__free_hook = freehook;
__malloc_hook = mallochook;
__realloc_hook = reallochook;
if (hdr == NULL)
return NULL;
hdr->size = size;
((char *) &hdr[1])[size] = MAGICBYTE;
return (PTR) (hdr + 1);
}
void
DEFUN(mcheck, (func), void EXFUN((*func), (void)))
{
static int mcheck_used = 0;
if (func)
abortfunc = func;
/* These hooks may not be safely inserted if malloc is already in use. */
if (!__malloc_initialized && !mcheck_used)
{
old_free_hook = __free_hook;
__free_hook = freehook;
old_malloc_hook = __malloc_hook;
__malloc_hook = mallochook;
old_realloc_hook = __realloc_hook;
__realloc_hook = reallochook;
mcheck_used = 1;
}
}
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