/*
* Standard debugging hooks for `malloc'.
* * Copyright 1990, 1991, 1992, 1993, 1994 Free Software Foundation, Inc.
* * Written May 1989 by Mike Haertel.
* *
* * This library is free software; you can redistribute it and/or
* * modify it under the terms of the GNU Library General Public License as
* * published by the Free Software Foundation; either version 2 of the
* * License, or (at your option) any later version.
* *
* * This 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
* * Library General Public License for more details.
* *
* * You should have received a copy of the GNU Library General Public
* * License along with this library; see the file COPYING.LIB. If
* * not, write to the Free Software Foundation, Inc., 675 Mass Ave,
* * Cambridge, MA 02139, USA.
* *
* * The author may be reached (Email) at the address mike@ai.mit.edu,
* * or (US mail) as Mike Haertel c/o Free Software Foundation.
*/
#ifndef _MALLOC_INTERNAL
#define _MALLOC_INTERNAL
#include <stdio.h>
#endif
#include "copyright.h"
#include "config.h"
#include "externs.h"
/*
* Old hook values.
*/
static void (*old_free_hook) __P((__ptr_t ptr));
static __ptr_t(*old_malloc_hook) __P((__malloc_size_t size));
static __ptr_t(*old_realloc_hook) __P((__ptr_t ptr, __malloc_size_t size));
/*
* Function to call when something awful happens.
*/
static void (*abortfunc) __P((enum mcheck_status));
/*
* Arbitrary magical numbers.
*/
#define MAGICWORD 0xfedabeeb
#define MAGICFREE 0xd8675309
#define MAGICBYTE ((char) 0xd7)
#define MALLOCFLOOD ((char) 0x93)
#define FREEFLOOD ((char) 0x95)
struct hdr {
__malloc_size_t size; /*
* Exact size requested by user.
*/
unsigned long int magic; /*
* Magic number to check header * *
* integrity.
*/
};
#if defined(_LIBC) || defined(STDC_HEADERS) || defined(USG)
#define flood memset
#else
static void flood __P((__ptr_t, int, __malloc_size_t));
static void flood(ptr, val, size)
__ptr_t ptr;
int val;
__malloc_size_t size;
{
char *cp = ptr;
while (size--)
*cp++ = val;
}
#endif
static enum mcheck_status checkhdr __P((const struct hdr *));
static enum mcheck_status checkhdr(hdr)
const struct hdr *hdr;
{
enum mcheck_status status;
switch (hdr->magic) {
default:
status = MCHECK_HEAD;
break;
case MAGICFREE:
status = MCHECK_FREE;
break;
case MAGICWORD:
if (((char *) &hdr[1])[hdr->size] != MAGICBYTE)
status = MCHECK_TAIL;
else
status = MCHECK_OK;
break;
}
if (status != MCHECK_OK)
(*abortfunc) (status);
return status;
}
static void freehook __P((__ptr_t));
static void freehook(ptr)
__ptr_t ptr;
{
struct hdr *hdr = ((struct hdr *) ptr) - 1;
checkhdr(hdr);
hdr->magic = MAGICFREE;
flood(ptr, FREEFLOOD, hdr->size);
__free_hook = old_free_hook;
free(hdr);
__free_hook = freehook;
}
static __ptr_t mallochook __P((__malloc_size_t));
static __ptr_t mallochook(size)
__malloc_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;
flood((__ptr_t) (hdr + 1), MALLOCFLOOD, size);
return (__ptr_t) (hdr + 1);
}
static __ptr_t reallochook __P((__ptr_t, __malloc_size_t));
static __ptr_t reallochook(ptr, size)
__ptr_t ptr;
__malloc_size_t size;
{
struct hdr *hdr = ((struct hdr *) ptr) - 1;
__malloc_size_t osize = hdr->size;
checkhdr(hdr);
if (size < osize)
flood((char *) ptr + size, FREEFLOOD, osize - size);
__free_hook = old_free_hook;
__malloc_hook = old_malloc_hook;
__realloc_hook = old_realloc_hook;
hdr =
(struct hdr *) realloc((__ptr_t) hdr,
sizeof(struct hdr) + size + 1);
__free_hook = freehook;
__malloc_hook = mallochook;
__realloc_hook = reallochook;
if (hdr == NULL)
return NULL;
hdr->size = size;
hdr->magic = MAGICWORD;
((char *) &hdr[1])[size] = MAGICBYTE;
if (size > osize)
flood((char *) (hdr + 1) + osize, MALLOCFLOOD, size - osize);
return (__ptr_t) (hdr + 1);
}
static void mabort(status)
enum mcheck_status status;
{
const char *msg;
switch (status) {
case MCHECK_OK:
msg = "memory is consistent, library is buggy";
break;
case MCHECK_HEAD:
msg = "memory clobbered before allocated block";
break;
case MCHECK_TAIL:
msg = "memory clobbered past end of allocated block";
break;
case MCHECK_FREE:
msg = "block freed twice";
break;
default:
msg = "bogus mcheck_status, library is buggy";
break;
}
STARTLOG(LOG_ALWAYS, "BUG", "MLLOC") {
log_text(tprintf("mcheck: %s\n", msg));
ENDLOG;
}
}
static int mcheck_used = 0;
int mcheck(void)
{
abortfunc = &mabort;
/*
* 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;
}
return mcheck_used ? 0 : -1;
}
enum mcheck_status mprobe(__ptr_t ptr)
{
return mcheck_used ? checkhdr(ptr) : MCHECK_DISABLED;
}