125 lines
3.3 KiB
C
125 lines
3.3 KiB
C
/* Standard debugging hooks for `malloc'.
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Copyright 1990, 1991 Free Software Foundation
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Written May 1989 by Mike Haertel.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, write to the Free Software Foundation, Inc., 675 Mass Ave,
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Cambridge, MA 02139, USA.
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The author may be reached (Email) at the address mike@ai.mit.edu,
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or (US mail) as Mike Haertel c/o Free Software Foundation. */
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/* IGNORE(@ */
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#include <ansidecl.h>
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#include <stdlib.h>
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/* @) */
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#include <malloc.h>
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/* Old hook values. */
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static void EXFUN((*old_free_hook), (PTR ptr));
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static PTR EXFUN((*old_malloc_hook), (size_t size));
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static PTR EXFUN((*old_realloc_hook), (PTR ptr, size_t size));
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/* Function to call when something awful happens. */
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extern void EXFUN(abort, (NOARGS));
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static void EXFUN((*abortfunc), (NOARGS)) = (void EXFUN((*), (NOARGS))) abort;
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/* Arbitrary magical numbers. */
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#define MAGICWORD 0xfedabeeb
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#define MAGICBYTE ((char) 0xd7)
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struct hdr
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{
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size_t size; /* Exact size requested by user. */
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unsigned long int magic; /* Magic number to check header integrity. */
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};
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static void
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DEFUN(checkhdr, (hdr), CONST struct hdr *hdr)
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{
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if (hdr->magic != MAGICWORD || ((char *) &hdr[1])[hdr->size] != MAGICBYTE)
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(*abortfunc)();
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}
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static void
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DEFUN(freehook, (ptr), PTR ptr)
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{
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struct hdr *hdr = ((struct hdr *) ptr) - 1;
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checkhdr(hdr);
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hdr->magic = 0;
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__free_hook = old_free_hook;
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free(hdr);
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__free_hook = freehook;
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}
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static PTR
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DEFUN(mallochook, (size), size_t size)
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{
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struct hdr *hdr;
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__malloc_hook = old_malloc_hook;
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hdr = (struct hdr *) malloc (sizeof(struct hdr) + size + 1);
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__malloc_hook = mallochook;
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if (hdr == NULL)
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return NULL;
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hdr->size = size;
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hdr->magic = MAGICWORD;
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((char *) &hdr[1])[size] = MAGICBYTE;
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return (PTR) (hdr + 1);
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}
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static PTR
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DEFUN(reallochook, (ptr, size), PTR ptr AND size_t size)
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{
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struct hdr *hdr = ((struct hdr *) ptr) - 1;
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checkhdr(hdr);
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__free_hook = old_free_hook;
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__malloc_hook = old_malloc_hook;
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__realloc_hook = old_realloc_hook;
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hdr = (struct hdr *) realloc((PTR) hdr, sizeof(struct hdr) + size + 1);
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__free_hook = freehook;
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__malloc_hook = mallochook;
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__realloc_hook = reallochook;
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if (hdr == NULL)
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return NULL;
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hdr->size = size;
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((char *) &hdr[1])[size] = MAGICBYTE;
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return (PTR) (hdr + 1);
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}
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void
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DEFUN(mcheck, (func), void EXFUN((*func), (void)))
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{
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static int mcheck_used = 0;
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if (func != NULL)
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abortfunc = func;
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/* These hooks may not be safely inserted if malloc is already in use. */
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if (!__malloc_initialized && !mcheck_used)
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{
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old_free_hook = __free_hook;
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__free_hook = freehook;
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old_malloc_hook = __malloc_hook;
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__malloc_hook = mallochook;
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old_realloc_hook = __realloc_hook;
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__realloc_hook = reallochook;
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mcheck_used = 1;
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}
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}
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