1/* Standard debugging hooks for `malloc'. 2 Copyright 1990, 1991, 1992, 1993 Free Software Foundation 3 Written May 1989 by Mike Haertel. 4 5This library is free software; you can redistribute it and/or 6modify it under the terms of the GNU Library General Public License as 7published by the Free Software Foundation; either version 2 of the 8License, or (at your option) any later version. 9 10This library is distributed in the hope that it will be useful, 11but WITHOUT ANY WARRANTY; without even the implied warranty of 12MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13Library General Public License for more details. 14 15You should have received a copy of the GNU Library General Public 16License along with this library; see the file COPYING.LIB. If 17not, write to the Free Software Foundation, Inc., 675 Mass Ave, 18Cambridge, MA 02139, USA. 19 20 The author may be reached (Email) at the address mike@ai.mit.edu, 21 or (US mail) as Mike Haertel c/o Free Software Foundation. */ 22 23#ifndef _MALLOC_INTERNAL 24#define _MALLOC_INTERNAL 25#include <malloc.h> 26#endif 27 28/* Old hook values. */ 29static void (*old_free_hook) __P ((__ptr_t ptr)); 30static __ptr_t (*old_malloc_hook) __P ((size_t size)); 31static __ptr_t (*old_realloc_hook) __P ((__ptr_t ptr, size_t size)); 32 33/* Function to call when something awful happens. */ 34static void (*abortfunc) __P ((void)); 35 36/* Arbitrary magical numbers. */ 37#define MAGICWORD 0xfedabeeb 38#define MAGICBYTE ((char) 0xd7) 39 40struct hdr 41 { 42 size_t size; /* Exact size requested by user. */ 43 unsigned long int magic; /* Magic number to check header integrity. */ 44 }; 45 46static void checkhdr __P ((const struct hdr *)); 47static void 48checkhdr (hdr) 49 const struct hdr *hdr; 50{ 51 if (hdr->magic != MAGICWORD || ((char *) &hdr[1])[hdr->size] != MAGICBYTE) 52 (*abortfunc) (); 53} 54 55static void freehook __P ((__ptr_t)); 56static void 57freehook (ptr) 58 __ptr_t ptr; 59{ 60 struct hdr *hdr = ((struct hdr *) ptr) - 1; 61 checkhdr (hdr); 62 hdr->magic = 0; 63 __free_hook = old_free_hook; 64 free (hdr); 65 __free_hook = freehook; 66} 67 68static __ptr_t mallochook __P ((size_t)); 69static __ptr_t 70mallochook (size) 71 size_t size; 72{ 73 struct hdr *hdr; 74 75 __malloc_hook = old_malloc_hook; 76 hdr = (struct hdr *) malloc (sizeof (struct hdr) + size + 1); 77 __malloc_hook = mallochook; 78 if (hdr == NULL) 79 return NULL; 80 81 hdr->size = size; 82 hdr->magic = MAGICWORD; 83 ((char *) &hdr[1])[size] = MAGICBYTE; 84 return (__ptr_t) (hdr + 1); 85} 86 87static __ptr_t reallochook __P ((__ptr_t, size_t)); 88static __ptr_t 89reallochook (ptr, size) 90 __ptr_t ptr; 91 size_t size; 92{ 93 struct hdr *hdr = ((struct hdr *) ptr) - 1; 94 95 checkhdr (hdr); 96 __free_hook = old_free_hook; 97 __malloc_hook = old_malloc_hook; 98 __realloc_hook = old_realloc_hook; 99 hdr = (struct hdr *) realloc ((__ptr_t) hdr, sizeof (struct hdr) + size + 1); 100 __free_hook = freehook; 101 __malloc_hook = mallochook; 102 __realloc_hook = reallochook; 103 if (hdr == NULL) 104 return NULL; 105 106 hdr->size = size; 107 ((char *) &hdr[1])[size] = MAGICBYTE; 108 return (__ptr_t) (hdr + 1); 109} 110 111int 112mcheck (func) 113 void (*func) __P ((void)); 114{ 115 extern void abort __P ((void)); 116 static int mcheck_used = 0; 117 118 abortfunc = (func != NULL) ? func : abort; 119 120 /* These hooks may not be safely inserted if malloc is already in use. */ 121 if (!__malloc_initialized && !mcheck_used) 122 { 123 old_free_hook = __free_hook; 124 __free_hook = freehook; 125 old_malloc_hook = __malloc_hook; 126 __malloc_hook = mallochook; 127 old_realloc_hook = __realloc_hook; 128 __realloc_hook = reallochook; 129 mcheck_used = 1; 130 } 131 132 return mcheck_used ? 0 : -1; 133} 134