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 1, or (at your option)
   9    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    The author may be reached (Email) at the address mike@ai.mit.edu,
  21    or (US mail) as Mike Haertel c/o Free Software Foundation. */
  22
  23 #include <stdio.h>
  24 #include "ansidecl.h"
  25
  26 /* size_t may be defined in the system-supplied stdio.h.  */
  27 /* So just kludge it.  */
  28 #define size_t unsigned int
  29 #define ptrdiff_t int
  30 #define __ONEFILE
  31
  32 #include <stdlib.h>
  33 #include "gmalloc.h"
  34
  35 extern char *getenv();
  36
  37 FILE *mallstream;
  38 char mallenv[] = "MALLOC_TRACE";
  39 static char mallbuf[BUFSIZ];            /* Buffer for the output */
  40
  41 /* Address to breakpoint on accesses to... */
  42 PTR mallwatch;
  43
  44 /* Old hook values.  */
  45 static void EXFUN((*old_free_hook), (PTR ptr));
  46 static PTR EXFUN((*old_malloc_hook), (size_t size));
  47 static PTR EXFUN((*old_realloc_hook), (PTR ptr, size_t size));
  48
  49 /* This function is called when the block being alloc'd, realloc'd, or
  50    freed has an address matching the variable "mallwatch".  In a debugger,
  51    set "mallwatch" to the address of interest, then put a breakpoint on
  52    tr_break.  */
  53
  54 void
  55 tr_break()
  56 {
  57   ;
  58 }
  59
  60 static void
  61 DEFUN(tr_freehook, (ptr), PTR ptr)
  62 {
  63   fprintf(mallstream, "- %08x\n", ptr); /* Be sure to print it first */
  64   if (ptr == mallwatch)
  65     tr_break();
  66   __free_hook = old_free_hook;
  67   free(ptr);
  68   __free_hook = tr_freehook;
  69 }
  70
  71 static PTR
  72 DEFUN(tr_mallochook, (size), size_t size)
  73 {
  74   PTR hdr;
  75
  76   __malloc_hook = old_malloc_hook;
  77   hdr = malloc(size);
  78   __malloc_hook = tr_mallochook;
  79
  80   /* We could be printing a NULL here; that's OK */
  81   fprintf (mallstream, "+ %08x %x\n", hdr, size);
  82
  83   if (hdr == mallwatch)
  84     tr_break();
  85
  86   return hdr;
  87 }
  88
  89 static PTR
  90 DEFUN(tr_reallochook, (ptr, size), PTR ptr AND size_t size)
  91 {
  92   PTR hdr;
  93
  94   if (ptr == mallwatch)
  95     tr_break();
  96
  97   __free_hook = old_free_hook;
  98   __malloc_hook = old_malloc_hook;
  99   __realloc_hook = old_realloc_hook;
 100   hdr = realloc(ptr, size);
 101   __free_hook = tr_freehook;
 102   __malloc_hook = tr_mallochook;
 103   __realloc_hook = tr_reallochook;
 104   if (hdr == NULL) {
 105     fprintf (mallstream, "! %08x %x\n", ptr, size);     /* Failed realloc */
 106   } else {
 107     fprintf (mallstream, "< %08x\n> %08x %x\n", ptr, hdr, size);
 108   }
 109
 110   if (hdr == mallwatch)
 111     tr_break();
 112
 113   return hdr;
 114 }
 115
 116 void
 117 mtrace()
 118 {
 119   char *mallfile;
 120
 121   mallfile = getenv (mallenv);
 122   if (mallfile) {
 123     mallstream = fopen (mallfile, "w");
 124     if (mallstream) {
 125       /* Be sure it doesn't malloc its buffer! */
 126       setbuf (mallstream, mallbuf);
 127       fprintf (mallstream, "= Start\n");
 128       old_free_hook = __free_hook;
 129       __free_hook = tr_freehook;
 130       old_malloc_hook = __malloc_hook;
 131       __malloc_hook = tr_mallochook;
 132       old_realloc_hook = __realloc_hook;
 133       __realloc_hook = tr_reallochook;
 134     }
 135   }
 136 }