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 (at) 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 } 161
