| 1 | /* More debugging hooks for `mmalloc'. |
| 2 | Copyright 1991, 1992 Free Software Foundation |
| 3 | |
| 4 | Written April 2, 1991 by John Gilmore of Cygnus Support |
| 5 | Based on mcheck.c by Mike Haertel. |
| 6 | Modified Mar 1992 by Fred Fish. (fnf@cygnus.com) |
| 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 <stdio.h> |
| 23 | #include "mmalloc.h" |
| 24 | |
| 25 | #ifndef __GNU_LIBRARY__ |
| 26 | extern char *getenv (); |
| 27 | #endif |
| 28 | |
| 29 | static FILE *mallstream; |
| 30 | |
| 31 | #if 0 /* FIXME: Disabled for now. */ |
| 32 | static char mallenv[] = "MALLOC_TRACE"; |
| 33 | static char mallbuf[BUFSIZ]; /* Buffer for the output. */ |
| 34 | #endif |
| 35 | |
| 36 | /* Address to breakpoint on accesses to... */ |
| 37 | static PTR mallwatch; |
| 38 | |
| 39 | /* Old hook values. */ |
| 40 | |
| 41 | static void (*old_mfree_hook) PARAMS ((PTR, PTR)); |
| 42 | static PTR (*old_mmalloc_hook) PARAMS ((PTR, size_t)); |
| 43 | static PTR (*old_mrealloc_hook) PARAMS ((PTR, PTR, size_t)); |
| 44 | |
| 45 | /* This function is called when the block being alloc'd, realloc'd, or |
| 46 | freed has an address matching the variable "mallwatch". In a debugger, |
| 47 | set "mallwatch" to the address of interest, then put a breakpoint on |
| 48 | tr_break. */ |
| 49 | |
| 50 | static void |
| 51 | tr_break () |
| 52 | { |
| 53 | } |
| 54 | |
| 55 | static void |
| 56 | tr_freehook (md, ptr) |
| 57 | PTR md; |
| 58 | PTR ptr; |
| 59 | { |
| 60 | struct mdesc *mdp; |
| 61 | |
| 62 | mdp = MD_TO_MDP (md); |
| 63 | /* Be sure to print it first. */ |
| 64 | (void) fprintf (mallstream, "- %08x\n", (unsigned int) ptr); |
| 65 | if (ptr == mallwatch) |
| 66 | tr_break (); |
| 67 | mdp -> mfree_hook = old_mfree_hook; |
| 68 | mfree (md, ptr); |
| 69 | mdp -> mfree_hook = tr_freehook; |
| 70 | } |
| 71 | |
| 72 | static PTR |
| 73 | tr_mallochook (md, size) |
| 74 | PTR md; |
| 75 | size_t size; |
| 76 | { |
| 77 | PTR hdr; |
| 78 | struct mdesc *mdp; |
| 79 | |
| 80 | mdp = MD_TO_MDP (md); |
| 81 | mdp -> mmalloc_hook = old_mmalloc_hook; |
| 82 | hdr = (PTR) mmalloc (md, size); |
| 83 | mdp -> mmalloc_hook = tr_mallochook; |
| 84 | |
| 85 | /* We could be printing a NULL here; that's OK. */ |
| 86 | (void) fprintf (mallstream, "+ %08x %x\n", (unsigned int) hdr, size); |
| 87 | |
| 88 | if (hdr == mallwatch) |
| 89 | tr_break (); |
| 90 | |
| 91 | return (hdr); |
| 92 | } |
| 93 | |
| 94 | static PTR |
| 95 | tr_reallochook (md, ptr, size) |
| 96 | PTR md; |
| 97 | PTR ptr; |
| 98 | size_t size; |
| 99 | { |
| 100 | PTR hdr; |
| 101 | struct mdesc *mdp; |
| 102 | |
| 103 | mdp = MD_TO_MDP (md); |
| 104 | |
| 105 | if (ptr == mallwatch) |
| 106 | tr_break (); |
| 107 | |
| 108 | mdp -> mfree_hook = old_mfree_hook; |
| 109 | mdp -> mmalloc_hook = old_mmalloc_hook; |
| 110 | mdp -> mrealloc_hook = old_mrealloc_hook; |
| 111 | hdr = (PTR) mrealloc (md, ptr, size); |
| 112 | mdp -> mfree_hook = tr_freehook; |
| 113 | mdp -> mmalloc_hook = tr_mallochook; |
| 114 | mdp -> mrealloc_hook = tr_reallochook; |
| 115 | if (hdr == NULL) |
| 116 | /* Failed realloc. */ |
| 117 | (void) fprintf (mallstream, "! %08x %x\n", (unsigned int) ptr, size); |
| 118 | else |
| 119 | (void) fprintf (mallstream, "< %08x\n> %08x %x\n", (unsigned int) ptr, |
| 120 | (unsigned int) hdr, size); |
| 121 | |
| 122 | if (hdr == mallwatch) |
| 123 | tr_break (); |
| 124 | |
| 125 | return hdr; |
| 126 | } |
| 127 | |
| 128 | /* We enable tracing if either the environment variable MALLOC_TRACE |
| 129 | is set, or if the variable mallwatch has been patched to an address |
| 130 | that the debugging user wants us to stop on. When patching mallwatch, |
| 131 | don't forget to set a breakpoint on tr_break! */ |
| 132 | |
| 133 | int |
| 134 | mmtrace () |
| 135 | { |
| 136 | #if 0 /* FIXME! This is disabled for now until we figure out how to |
| 137 | maintain a stack of hooks per heap, since we might have other |
| 138 | hooks (such as set by mmcheck) active also. */ |
| 139 | char *mallfile; |
| 140 | |
| 141 | mallfile = getenv (mallenv); |
| 142 | if (mallfile != NULL || mallwatch != NULL) |
| 143 | { |
| 144 | mallstream = fopen (mallfile != NULL ? mallfile : "/dev/null", "w"); |
| 145 | if (mallstream != NULL) |
| 146 | { |
| 147 | /* Be sure it doesn't mmalloc its buffer! */ |
| 148 | setbuf (mallstream, mallbuf); |
| 149 | (void) fprintf (mallstream, "= Start\n"); |
| 150 | old_mfree_hook = mdp -> mfree_hook; |
| 151 | mdp -> mfree_hook = tr_freehook; |
| 152 | old_mmalloc_hook = mdp -> mmalloc_hook; |
| 153 | mdp -> mmalloc_hook = tr_mallochook; |
| 154 | old_mrealloc_hook = mdp -> mrealloc_hook; |
| 155 | mdp -> mrealloc_hook = tr_reallochook; |
| 156 | } |
| 157 | } |
| 158 | |
| 159 | #endif /* 0 */ |
| 160 | |
| 161 | return (1); |
| 162 | } |
| 163 | |