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