| 1 | /* More debugging hooks for `malloc'. |
| 2 | Copyright 1991 Free Software Foundation |
| 3 | Written April 2, 1991 by John Gilmore of Cygnus Support |
| 4 | Based on mcheck.c by Mike Haertel. |
| 5 | |
| 6 | This program is free software; you can redistribute it and/or modify |
| 7 | it under the terms of the GNU General Public License as published by |
| 8 | the Free Software Foundation; either version 2 of the License, or |
| 9 | (at your option) any later version. |
| 10 | |
| 11 | This program is distributed in the hope that it will be useful, |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | GNU General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU General Public License |
| 17 | along with this program; if not, write to the Free Software |
| 18 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ |
| 19 | |
| 20 | #include <stdio.h> |
| 21 | #include "ansidecl.h" |
| 22 | |
| 23 | /* size_t may be defined in the system-supplied stdio.h. */ |
| 24 | /* So just kludge it. */ |
| 25 | #define size_t unsigned int |
| 26 | #define ptrdiff_t int |
| 27 | #define __ONEFILE |
| 28 | |
| 29 | /* We can't declare malloc and realloc here because we don't know |
| 30 | if they are char * or void *, and the compiler will give an error |
| 31 | if we get it wrong and they happen to be defined in some header |
| 32 | file e.g. <stdio.h>. We can't include <stdlib.h> here because |
| 33 | it has some incompatability with our own includes, e.g. size_t or |
| 34 | whatever. So we just punt. This causes malloc and realloc to |
| 35 | default to returning "int", which works for most cases we care |
| 36 | about. FIXME-somehow. */ |
| 37 | /* #include <stdlib.h> */ |
| 38 | #include "gmalloc.h" |
| 39 | |
| 40 | extern char *getenv(); |
| 41 | |
| 42 | FILE *mallstream; |
| 43 | char mallenv[] = "MALLOC_TRACE"; |
| 44 | static char mallbuf[BUFSIZ]; /* Buffer for the output */ |
| 45 | |
| 46 | /* Address to breakpoint on accesses to... */ |
| 47 | PTR mallwatch; |
| 48 | |
| 49 | /* Old hook values. */ |
| 50 | static void EXFUN((*old_free_hook), (PTR ptr)); |
| 51 | static PTR EXFUN((*old_malloc_hook), (size_t size)); |
| 52 | static PTR EXFUN((*old_realloc_hook), (PTR ptr, size_t size)); |
| 53 | |
| 54 | /* This function is called when the block being alloc'd, realloc'd, or |
| 55 | freed has an address matching the variable "mallwatch". In a debugger, |
| 56 | set "mallwatch" to the address of interest, then put a breakpoint on |
| 57 | tr_break. */ |
| 58 | |
| 59 | void |
| 60 | tr_break() |
| 61 | { |
| 62 | ; |
| 63 | } |
| 64 | |
| 65 | static void |
| 66 | DEFUN(tr_freehook, (ptr), PTR ptr) |
| 67 | { |
| 68 | fprintf(mallstream, "- %08x\n", ptr); /* Be sure to print it first */ |
| 69 | if (ptr == mallwatch) |
| 70 | tr_break(); |
| 71 | __free_hook = old_free_hook; |
| 72 | free(ptr); |
| 73 | __free_hook = tr_freehook; |
| 74 | } |
| 75 | |
| 76 | static PTR |
| 77 | DEFUN(tr_mallochook, (size), size_t size) |
| 78 | { |
| 79 | PTR hdr; |
| 80 | |
| 81 | __malloc_hook = old_malloc_hook; |
| 82 | hdr = (PTR) malloc(size); |
| 83 | __malloc_hook = tr_mallochook; |
| 84 | |
| 85 | /* We could be printing a NULL here; that's OK */ |
| 86 | fprintf (mallstream, "+ %08x %x\n", hdr, size); |
| 87 | |
| 88 | if (hdr == mallwatch) |
| 89 | tr_break(); |
| 90 | |
| 91 | return hdr; |
| 92 | } |
| 93 | |
| 94 | static PTR |
| 95 | DEFUN(tr_reallochook, (ptr, size), PTR ptr AND size_t size) |
| 96 | { |
| 97 | PTR hdr; |
| 98 | |
| 99 | if (ptr == mallwatch) |
| 100 | tr_break(); |
| 101 | |
| 102 | __free_hook = old_free_hook; |
| 103 | __malloc_hook = old_malloc_hook; |
| 104 | __realloc_hook = old_realloc_hook; |
| 105 | hdr = (PTR) realloc(ptr, size); |
| 106 | __free_hook = tr_freehook; |
| 107 | __malloc_hook = tr_mallochook; |
| 108 | __realloc_hook = tr_reallochook; |
| 109 | if (hdr == NULL) { |
| 110 | fprintf (mallstream, "! %08x %x\n", ptr, size); /* Failed realloc */ |
| 111 | } else { |
| 112 | fprintf (mallstream, "< %08x\n> %08x %x\n", ptr, hdr, size); |
| 113 | } |
| 114 | |
| 115 | if (hdr == mallwatch) |
| 116 | tr_break(); |
| 117 | |
| 118 | return hdr; |
| 119 | } |
| 120 | |
| 121 | /* We enable tracing if either the environment variable MALLOC_TRACE |
| 122 | is set, or if the variable mallwatch has been patched to an address |
| 123 | that the debugging user wants us to stop on. When patching mallwatch, |
| 124 | don't forget to set a breakpoint on tr_break! */ |
| 125 | |
| 126 | void |
| 127 | mtrace() |
| 128 | { |
| 129 | char *mallfile; |
| 130 | |
| 131 | mallfile = getenv (mallenv); |
| 132 | if (mallfile || mallwatch) { |
| 133 | mallstream = fopen (mallfile? mallfile: "/dev/null", "w"); |
| 134 | if (mallstream) { |
| 135 | /* Be sure it doesn't malloc its buffer! */ |
| 136 | setbuf (mallstream, mallbuf); |
| 137 | fprintf (mallstream, "= Start\n"); |
| 138 | old_free_hook = __free_hook; |
| 139 | __free_hook = tr_freehook; |
| 140 | old_malloc_hook = __malloc_hook; |
| 141 | __malloc_hook = tr_mallochook; |
| 142 | old_realloc_hook = __realloc_hook; |
| 143 | __realloc_hook = tr_reallochook; |
| 144 | } |
| 145 | } |
| 146 | } |