/* Standard debugging hooks for `malloc'. Copyright (C) 1990,91,92,93,94,95,96,97 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 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 <malloc.h> #include <mcheck.h> #include <stdio.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. */ }; #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; 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, const __ptr_t)); static void freehook (ptr, caller) __ptr_t ptr; const __ptr_t caller; { if (ptr) { struct hdr *hdr = ((struct hdr *) ptr) - 1; checkhdr (hdr); hdr->magic = MAGICFREE; 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; __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; 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, 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 (ptr) { hdr = ((struct hdr *) ptr) - 1; osize = hdr->size; checkhdr (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; 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 __P ((enum mcheck_status status)); 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; } #ifdef _LIBC __libc_fatal (msg); #else fprintf (stderr, "mcheck: %s\n", msg); fflush (stderr); abort (); #endif } static int mcheck_used = 0; 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 && !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; }