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 */
malloc_get_mallstream()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
tr_break()66 tr_break ()
67 {
68 }
69
70 static void tr_freehook __P ((__ptr_t));
71 static void
tr_freehook(ptr)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
tr_mallochook(size)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
tr_reallochook(ptr,size)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
mtrace()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 }
161