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