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Diffstat (limited to 'malloc/mtrace.c')
| -rw-r--r-- | malloc/mtrace.c | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/malloc/mtrace.c b/malloc/mtrace.c new file mode 100644 index 0000000..35380a0 --- /dev/null +++ b/malloc/mtrace.c @@ -0,0 +1,211 @@ +/* More debugging hooks for `malloc'. + Copyright (C) 1991, 1992, 1993, 1994, 1996 Free Software Foundation, Inc. + Written April 2, 1991 by John Gilmore of Cygnus Support. + Based on mcheck.c by Mike Haertel. + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public License as + published by the Free Software Foundation; either version 2 of the + License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with this library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. + + The author may be reached (Email) at the address mike@ai.mit.edu, + or (US mail) as Mike Haertel c/o Free Software Foundation. */ + +#ifndef _MALLOC_INTERNAL +#define _MALLOC_INTERNAL +#include <malloc.h> +#include <mcheck.h> +#include <libc-lock.h> +#endif + +#include <stdio.h> + +#ifndef __GNU_LIBRARY__ +extern char *getenv (); +#else +#include <stdlib.h> +#endif + +static FILE *mallstream; +static char mallenv[]= "MALLOC_TRACE"; +static char mallbuf[BUFSIZ]; /* Buffer for the output. */ + +__libc_lock_define_initialized (static, lock); + +/* Address to breakpoint on accesses to... */ +__ptr_t mallwatch; + +/* File name and line number information, for callers that had + the foresight to call through a macro. */ +char *_mtrace_file; +int _mtrace_line; + +/* Old hook values. */ +static void (*tr_old_free_hook) __P ((__ptr_t ptr)); +static __ptr_t (*tr_old_malloc_hook) __P ((__malloc_size_t size)); +static __ptr_t (*tr_old_realloc_hook) __P ((__ptr_t ptr, __malloc_size_t size)); + +/* This function is called when the block being alloc'd, realloc'd, or + freed has an address matching the variable "mallwatch". In a debugger, + set "mallwatch" to the address of interest, then put a breakpoint on + tr_break. */ + +void tr_break __P ((void)); +void +tr_break () +{ +} + +static void tr_where __P ((void)); +static void +tr_where () +{ + if (_mtrace_file) + { + fprintf (mallstream, "@ %s:%d ", _mtrace_file, _mtrace_line); + _mtrace_file = NULL; + } +} + +static void tr_freehook __P ((__ptr_t)); +static void +tr_freehook (ptr) + __ptr_t ptr; +{ + tr_where (); + fprintf (mallstream, "- %p\n", ptr); /* Be sure to print it first. */ + if (ptr == mallwatch) + tr_break (); + __libc_lock_lock (lock); + __free_hook = tr_old_free_hook; + free (ptr); + __free_hook = tr_freehook; + __libc_lock_unlock (lock); +} + +static __ptr_t tr_mallochook __P ((__malloc_size_t)); +static __ptr_t +tr_mallochook (size) + __malloc_size_t size; +{ + __ptr_t hdr; + + __libc_lock_lock (lock); + + __malloc_hook = tr_old_malloc_hook; + hdr = (__ptr_t) malloc (size); + __malloc_hook = tr_mallochook; + + __libc_lock_unlock (lock); + + tr_where (); + /* We could be printing a NULL here; that's OK. */ + fprintf (mallstream, "+ %p %lx\n", hdr, (unsigned long)size); + + if (hdr == mallwatch) + tr_break (); + + return hdr; +} + +static __ptr_t tr_reallochook __P ((__ptr_t, __malloc_size_t)); +static __ptr_t +tr_reallochook (ptr, size) + __ptr_t ptr; + __malloc_size_t size; +{ + __ptr_t hdr; + + if (ptr == mallwatch) + tr_break (); + + __libc_lock_lock (lock); + + __free_hook = tr_old_free_hook; + __malloc_hook = tr_old_malloc_hook; + __realloc_hook = tr_old_realloc_hook; + hdr = (__ptr_t) realloc (ptr, size); + __free_hook = tr_freehook; + __malloc_hook = tr_mallochook; + __realloc_hook = tr_reallochook; + + __libc_lock_unlock (lock); + + tr_where (); + if (hdr == NULL) + /* Failed realloc. */ + fprintf (mallstream, "! %p %lx\n", ptr, (unsigned long)size); + else if (ptr == NULL) + fprintf (mallstream, "+ %p %lx\n", hdr, (unsigned long)size); + else + fprintf (mallstream, "< %p\n> %p %lx\n", ptr, hdr, (unsigned long)size); + + if (hdr == mallwatch) + tr_break (); + + return hdr; +} + +/* We enable tracing if either the environment variable MALLOC_TRACE + is set, or if the variable mallwatch has been patched to an address + that the debugging user wants us to stop on. When patching mallwatch, + don't forget to set a breakpoint on tr_break! */ + +void +mtrace () +{ + char *mallfile; + + /* Don't panic if we're called more than once. */ + if (mallstream != NULL) + return; + +#ifdef _LIBC + /* When compiling the GNU libc we use the secure getenv function + which prevents the misuse in case of SUID or SGID enabled + programs. */ + mallfile = __secure_getenv (mallenv); +#else + mallfile = getenv (mallenv); +#endif + if (mallfile != NULL || mallwatch != NULL) + { + mallstream = fopen (mallfile != NULL ? mallfile : "/dev/null", "w"); + if (mallstream != NULL) + { + /* Be sure it doesn't malloc its buffer! */ + setbuf (mallstream, mallbuf); + fprintf (mallstream, "= Start\n"); + tr_old_free_hook = __free_hook; + __free_hook = tr_freehook; + tr_old_malloc_hook = __malloc_hook; + __malloc_hook = tr_mallochook; + tr_old_realloc_hook = __realloc_hook; + __realloc_hook = tr_reallochook; + } + } +} + +void +muntrace () +{ + if (mallstream == NULL) + return; + + fprintf (mallstream, "= End\n"); + fclose (mallstream); + mallstream = NULL; + __free_hook = tr_old_free_hook; + __malloc_hook = tr_old_malloc_hook; + __realloc_hook = tr_old_realloc_hook; +} |