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1 | /* More debugging hooks for `malloc'. | |
2 | Copyright (C) 1991, 1992 Free Software Foundation, Inc. | |
3 | Written April 2, 1991 by John Gilmore of Cygnus Support. | |
4 | Based on mcheck.c by Mike Haertel. | |
5 | ||
6 | This library is free software; you can redistribute it and/or | |
7 | modify it under the terms of the GNU Library General Public License as | |
8 | published by the Free Software Foundation; either version 2 of the | |
9 | License, or (at your option) any later version. | |
10 | ||
11 | This library 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 GNU | |
14 | Library General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU Library General Public | |
17 | License along with this library; see the file COPYING.LIB. If | |
18 | not, write to the Free Software Foundation, Inc., 675 Mass Ave, | |
19 | Cambridge, MA 02139, USA. | |
20 | ||
21 | The author may be reached (Email) at the address mike@ai.mit.edu, | |
22 | or (US mail) as Mike Haertel c/o Free Software Foundation. */ | |
23 | ||
24 | #include "config.h" | |
25 | ||
26 | #ifndef _MALLOC_INTERNAL | |
27 | #define _MALLOC_INTERNAL | |
28 | #include "./mtrace.h" | |
29 | #endif | |
30 | ||
31 | #include <stdio.h> | |
32 | ||
33 | #ifndef __GNU_LIBRARY__ | |
34 | extern char *getenv (); | |
35 | #else | |
36 | #include <stdlib.h> | |
37 | #endif | |
38 | ||
39 | static FILE *mallstream; | |
40 | static char mallenv[]= "MALLOC_TRACE"; | |
41 | static char mallbuf[BUFSIZ]; /* Buffer for the output. */ | |
42 | ||
43 | /* Address to breakpoint on accesses to... */ | |
44 | __ptr_t mallwatch; | |
45 | ||
46 | /* Old hook values. */ | |
47 | static void (*tr_old_free_hook) __P ((__ptr_t ptr)); | |
48 | static __ptr_t (*tr_old_malloc_hook) __P ((size_t size)); | |
49 | static __ptr_t (*tr_old_realloc_hook) __P ((__ptr_t ptr, size_t size)); | |
50 | ||
51 | /* | |
52 | * Added by TYT, 10/10/93 --- so that we can print | |
53 | */ | |
54 | FILE *malloc_get_mallstream() | |
55 | { | |
56 | return mallstream; | |
57 | } | |
58 | ||
59 | /* This function is called when the block being alloc'd, realloc'd, or | |
60 | freed has an address matching the variable "mallwatch". In a debugger, | |
61 | set "mallwatch" to the address of interest, then put a breakpoint on | |
62 | tr_break. */ | |
63 | ||
64 | void tr_break __P ((void)); | |
65 | void | |
66 | tr_break () | |
67 | { | |
68 | } | |
69 | ||
70 | static void tr_freehook __P ((__ptr_t)); | |
71 | static void | |
72 | tr_freehook (ptr) | |
73 | __ptr_t ptr; | |
74 | { | |
75 | fprintf (mallstream, "- %p\n", ptr); /* Be sure to print it first. */ | |
76 | if (ptr == mallwatch) | |
77 | tr_break (); | |
78 | __free_hook = tr_old_free_hook; | |
79 | free (ptr); | |
80 | __free_hook = tr_freehook; | |
81 | } | |
82 | ||
83 | static __ptr_t tr_mallochook __P ((size_t)); | |
84 | static __ptr_t | |
85 | tr_mallochook (size) | |
86 | size_t size; | |
87 | { | |
88 | __ptr_t hdr; | |
89 | ||
90 | __malloc_hook = tr_old_malloc_hook; | |
91 | hdr = (__ptr_t) malloc (size); | |
92 | __malloc_hook = tr_mallochook; | |
93 | ||
94 | /* We could be printing a NULL here; that's OK. */ | |
95 | fprintf (mallstream, "+ %p %d\n", hdr, size); | |
96 | ||
97 | if (hdr == mallwatch) | |
98 | tr_break (); | |
99 | ||
100 | return hdr; | |
101 | } | |
102 | ||
103 | static __ptr_t tr_reallochook __P ((__ptr_t, size_t)); | |
104 | static __ptr_t | |
105 | tr_reallochook (ptr, size) | |
106 | __ptr_t ptr; | |
107 | size_t size; | |
108 | { | |
109 | __ptr_t hdr; | |
110 | ||
111 | if (ptr == mallwatch) | |
112 | tr_break (); | |
113 | ||
114 | __free_hook = tr_old_free_hook; | |
115 | __malloc_hook = tr_old_malloc_hook; | |
116 | __realloc_hook = tr_old_realloc_hook; | |
117 | hdr = (__ptr_t) realloc (ptr, size); | |
118 | __free_hook = tr_freehook; | |
119 | __malloc_hook = tr_mallochook; | |
120 | __realloc_hook = tr_reallochook; | |
121 | if (hdr == NULL) | |
122 | /* Failed realloc. */ | |
123 | fprintf (mallstream, "! %p %d\n", ptr, size); | |
124 | else | |
125 | fprintf (mallstream, "< %p\n> %p %d\n", ptr, hdr, size); | |
126 | ||
127 | if (hdr == mallwatch) | |
128 | tr_break (); | |
129 | ||
130 | return hdr; | |
131 | } | |
132 | ||
133 | /* We enable tracing if either the environment variable MALLOC_TRACE | |
134 | is set, or if the variable mallwatch has been patched to an address | |
135 | that the debugging user wants us to stop on. When patching mallwatch, | |
136 | don't forget to set a breakpoint on tr_break! */ | |
137 | ||
138 | void | |
139 | mtrace () | |
140 | { | |
141 | char *mallfile; | |
142 | ||
143 | mallfile = getenv (mallenv); | |
144 | if (mallfile != NULL || mallwatch != NULL) | |
145 | { | |
146 | mallstream = fopen (mallfile != NULL ? mallfile : "/dev/null", "w"); | |
147 | if (mallstream != NULL) | |
148 | { | |
149 | /* Be sure it doesn't malloc its buffer! */ | |
150 | setbuf (mallstream, mallbuf); | |
151 | fprintf (mallstream, "= Start\n"); | |
152 | tr_old_free_hook = __free_hook; | |
153 | __free_hook = tr_freehook; | |
154 | tr_old_malloc_hook = __malloc_hook; | |
155 | __malloc_hook = tr_mallochook; | |
156 | tr_old_realloc_hook = __realloc_hook; | |
157 | __realloc_hook = tr_reallochook; | |
158 | } | |
159 | } | |
160 | } |