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libc/newlib/libc/sys/linux/mcheck.c

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/* Standard debugging hooks for `malloc'.
Copyright (C) 1990-1997, 1999, 2000, 2001 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Written May 1989 by Mike Haertel.
The GNU C 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 2.1 of the License, or (at your option) any later version.
The GNU C 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 C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
/* Modified for newlib, July 9, 2002 by Jeff Johnston */
#ifndef _MALLOC_INTERNAL
# define _MALLOC_INTERNAL
# include <features.h>
# define _LIBC 1
# include <malloc.h>
# include <mcheck.h>
# include <stdint.h>
# include <stdio.h>
# include <stdlib.h>
# include <libintl.h>
# include <sys/cdefs.h>
#endif
/* Old hook values. */
static void (*old_free_hook) __P ((__ptr_t ptr, __const __ptr_t));
static __ptr_t (*old_malloc_hook) __P ((__malloc_size_t size, const __ptr_t));
static __ptr_t (*old_realloc_hook) __P ((__ptr_t ptr, __malloc_size_t size,
__const __ptr_t));
/* 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. */
struct hdr *prev;
struct hdr *next;
};
/* This is the beginning of the list of all memory blocks allocated.
It is only constructed if the pedantic testing is requested. */
static struct hdr *root;
static int mcheck_used;
/* Nonzero if pedentic checking of all blocks is requested. */
static int pedantic;
#if defined _LIBC || defined STDC_HEADERS || defined USG
# include <string.h>
# 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;
if (!mcheck_used)
/* Maybe the mcheck used is disabled? This happens when we find
an error and report it. */
return MCHECK_OK;
switch (hdr->magic ^ ((uintptr_t) hdr->prev + (uintptr_t) hdr->next))
{
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)
{
mcheck_used = 0;
(*abortfunc) (status);
mcheck_used = 1;
}
return status;
}
void
mcheck_check_all ()
{
/* Walk through all the active blocks and test whether they were tempered
with. */
struct hdr *runp = root;
/* Temporarily turn off the checks. */
pedantic = 0;
while (runp != NULL)
{
(void) checkhdr (runp);
runp = runp->next;
}
/* Turn checks on again. */
pedantic = 1;
}
static void unlink_blk __P ((struct hdr *ptr));
static void
unlink_blk (ptr)
struct hdr *ptr;
{
if (ptr->next != NULL)
{
ptr->next->prev = ptr->prev;
ptr->next->magic = MAGICWORD ^ ((uintptr_t) ptr->next->prev
+ (uintptr_t) ptr->next->next);
}
if (ptr->prev != NULL)
{
ptr->prev->next = ptr->next;
ptr->prev->magic = MAGICWORD ^ ((uintptr_t) ptr->prev->prev
+ (uintptr_t) ptr->prev->next);
}
else
root = ptr->next;
}
static void link_blk __P ((struct hdr *ptr));
static void
link_blk (hdr)
struct hdr *hdr;
{
hdr->prev = NULL;
hdr->next = root;
root = hdr;
hdr->magic = MAGICWORD ^ (uintptr_t) hdr->next;
/* And the next block. */
if (hdr->next != NULL)
{
hdr->next->prev = hdr;
hdr->next->magic = MAGICWORD ^ ((uintptr_t) hdr
+ (uintptr_t) hdr->next->next);
}
}
static void freehook __P ((__ptr_t, const __ptr_t));
static void
freehook (ptr, caller)
__ptr_t ptr;
const __ptr_t caller;
{
if (pedantic)
mcheck_check_all ();
if (ptr)
{
struct hdr *hdr = ((struct hdr *) ptr) - 1;
checkhdr (hdr);
hdr->magic = MAGICFREE;
unlink_blk (hdr);
hdr->prev = hdr->next = NULL;
flood (ptr, FREEFLOOD, hdr->size);
ptr = (__ptr_t) hdr;
}
__free_hook = old_free_hook;
if (old_free_hook != NULL)
(*old_free_hook) (ptr, caller);
else
free (ptr);
__free_hook = freehook;
}
static __ptr_t mallochook __P ((__malloc_size_t, const __ptr_t));
static __ptr_t
mallochook (size, caller)
__malloc_size_t size;
const __ptr_t caller;
{
struct hdr *hdr;
if (pedantic)
mcheck_check_all ();
__malloc_hook = old_malloc_hook;
if (old_malloc_hook != NULL)
hdr = (struct hdr *) (*old_malloc_hook) (sizeof (struct hdr) + size + 1,
caller);
else
hdr = (struct hdr *) malloc (sizeof (struct hdr) + size + 1);
__malloc_hook = mallochook;
if (hdr == NULL)
return NULL;
hdr->size = size;
link_blk (hdr);
((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, const __ptr_t));
static __ptr_t
reallochook (ptr, size, caller)
__ptr_t ptr;
__malloc_size_t size;
const __ptr_t caller;
{
struct hdr *hdr;
__malloc_size_t osize;
if (pedantic)
mcheck_check_all ();
if (ptr)
{
hdr = ((struct hdr *) ptr) - 1;
osize = hdr->size;
checkhdr (hdr);
unlink_blk (hdr);
if (size < osize)
flood ((char *) ptr + size, FREEFLOOD, osize - size);
}
else
{
osize = 0;
hdr = NULL;
}
__free_hook = old_free_hook;
__malloc_hook = old_malloc_hook;
__realloc_hook = old_realloc_hook;
if (old_realloc_hook != NULL)
hdr = (struct hdr *) (*old_realloc_hook) ((__ptr_t) hdr,
sizeof (struct hdr) + size + 1,
caller);
else
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;
link_blk (hdr);
((char *) &hdr[1])[size] = MAGICBYTE;
if (size > osize)
flood ((char *) (hdr + 1) + osize, MALLOCFLOOD, size - osize);
return (__ptr_t) (hdr + 1);
}
static void mabort __P ((enum mcheck_status status))
__attribute__ ((noreturn));
static void
mabort (status)
enum mcheck_status status;
{
const char *msg;
switch (status)
{
case MCHECK_OK:
msg = _("memory is consistent, library is buggy\n");
break;
case MCHECK_HEAD:
msg = _("memory clobbered before allocated block\n");
break;
case MCHECK_TAIL:
msg = _("memory clobbered past end of allocated block\n");
break;
case MCHECK_FREE:
msg = _("block freed twice\n");
break;
default:
msg = _("bogus mcheck_status, library is buggy\n");
break;
}
fprintf (stderr, "mcheck: %s", msg);
fflush (stderr);
abort ();
}
int
mcheck (func)
void (*func) __P ((enum mcheck_status));
{
abortfunc = (func != NULL) ? func : &mabort;
/* These hooks may not be safely inserted if malloc is already in use. */
if (__malloc_initialized <= 0 && !mcheck_used)
{
/* We call malloc() once here to ensure it is initialized. */
void *p = malloc (0);
free (p);
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;
}
int
mcheck_pedantic (func)
void (*func) __P ((enum mcheck_status));
{
int res = mcheck (func);
if (res == 0)
pedantic = 1;
return res;
}
enum mcheck_status
mprobe (__ptr_t ptr)
{
return mcheck_used ? checkhdr (((struct hdr *) ptr) - 1) : MCHECK_DISABLED;
}
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