gdb/mtrace.c

   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 void
 122 mtrace()
 123 {
 124   char *mallfile;
 125
 126   mallfile = getenv (mallenv);
 127   if (mallfile) {
 128     mallstream = fopen (mallfile, "w");
 129     if (mallstream) {
 130       /* Be sure it doesn't malloc its buffer! */
 131       setbuf (mallstream, mallbuf);
 132       fprintf (mallstream, "= Start\n");
 133       old_free_hook = __free_hook;
 134       __free_hook = tr_freehook;
 135       old_malloc_hook = __malloc_hook;
 136       __malloc_hook = tr_mallochook;
 137       old_realloc_hook = __realloc_hook;
 138       __realloc_hook = tr_reallochook;
 139     }
 140   }
 141 }