glibc/malloc/mtrace.c

322 lines
8.2 KiB
C

/* More debugging hooks for `malloc'.
Copyright (C) 1991-1994,1996-2001,2002 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Written April 2, 1991 by John Gilmore of Cygnus Support.
Based on mcheck.c by Mike Haertel.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#ifndef _MALLOC_INTERNAL
#define _MALLOC_INTERNAL
#include <malloc.h>
#include <mcheck.h>
#include <bits/libc-lock.h>
#endif
#include <dlfcn.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdio-common/_itoa.h>
#ifdef _LIBC
# include <libc-internal.h>
# include <libio/iolibio.h>
# define setvbuf(s, b, f, l) INTUSE(_IO_setvbuf) (s, b, f, l)
# define fwrite(buf, size, count, fp) _IO_fwrite (buf, size, count, fp)
#endif
#ifndef attribute_hidden
# define attribute_hidden
#endif
#define TRACE_BUFFER_SIZE 512
static FILE *mallstream;
static const char mallenv[]= "MALLOC_TRACE";
static char malloc_trace_buffer[TRACE_BUFFER_SIZE];
__libc_lock_define_initialized (static, lock);
/* Address to breakpoint on accesses to... */
__ptr_t mallwatch;
#ifdef USE_MTRACE_FILE
/* File name and line number information, for callers that had
the foresight to call through a macro. */
char *_mtrace_file;
int _mtrace_line;
#endif
/* Old hook values. */
static void (*tr_old_free_hook) __P ((__ptr_t ptr, const __ptr_t));
static __ptr_t (*tr_old_malloc_hook) __P ((__malloc_size_t size,
const __ptr_t));
static __ptr_t (*tr_old_realloc_hook) __P ((__ptr_t ptr,
__malloc_size_t size,
const __ptr_t));
/* 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 ((const __ptr_t)) internal_function;
static void
internal_function
tr_where (caller)
const __ptr_t caller;
{
#ifdef USE_MTRACE_FILE
if (_mtrace_file)
{
fprintf (mallstream, "@ %s:%d ", _mtrace_file, _mtrace_line);
_mtrace_file = NULL;
}
else
#endif
if (caller != NULL)
{
#ifdef HAVE_ELF
Dl_info info;
if (_dl_addr (caller, &info))
{
char *buf = (char *) "";
if (info.dli_sname != NULL)
{
size_t len = strlen (info.dli_sname);
buf = alloca (len + 6 + 2 * sizeof (void *));
buf[0] = '(';
__stpcpy (_fitoa (caller >= (const __ptr_t) info.dli_saddr
? caller - (const __ptr_t) info.dli_saddr
: (const __ptr_t) info.dli_saddr - caller,
__stpcpy (__mempcpy (buf + 1, info.dli_sname,
len),
caller >= (__ptr_t) info.dli_saddr
? "+0x" : "-0x"),
16, 0),
")");
}
fprintf (mallstream, "@ %s%s%s[%p] ",
info.dli_fname ?: "", info.dli_fname ? ":" : "",
buf, caller);
}
else
#endif
fprintf (mallstream, "@ [%p] ", caller);
}
}
static void tr_freehook __P ((__ptr_t, const __ptr_t));
static void
tr_freehook (ptr, caller)
__ptr_t ptr;
const __ptr_t caller;
{
if (ptr == NULL)
return;
__libc_lock_lock (lock);
tr_where (caller);
/* Be sure to print it first. */
fprintf (mallstream, "- %p\n", ptr);
__libc_lock_unlock (lock);
if (ptr == mallwatch)
tr_break ();
__libc_lock_lock (lock);
__free_hook = tr_old_free_hook;
if (tr_old_free_hook != NULL)
(*tr_old_free_hook) (ptr, caller);
else
free (ptr);
__free_hook = tr_freehook;
__libc_lock_unlock (lock);
}
static __ptr_t tr_mallochook __P ((__malloc_size_t, const __ptr_t));
static __ptr_t
tr_mallochook (size, caller)
__malloc_size_t size;
const __ptr_t caller;
{
__ptr_t hdr;
__libc_lock_lock (lock);
__malloc_hook = tr_old_malloc_hook;
if (tr_old_malloc_hook != NULL)
hdr = (__ptr_t) (*tr_old_malloc_hook) (size, caller);
else
hdr = (__ptr_t) malloc (size);
__malloc_hook = tr_mallochook;
tr_where (caller);
/* We could be printing a NULL here; that's OK. */
fprintf (mallstream, "+ %p %#lx\n", hdr, (unsigned long int) size);
__libc_lock_unlock (lock);
if (hdr == mallwatch)
tr_break ();
return hdr;
}
static __ptr_t tr_reallochook __P ((__ptr_t, __malloc_size_t, const __ptr_t));
static __ptr_t
tr_reallochook (ptr, size, caller)
__ptr_t ptr;
__malloc_size_t size;
const __ptr_t caller;
{
__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;
if (tr_old_realloc_hook != NULL)
hdr = (__ptr_t) (*tr_old_realloc_hook) (ptr, size, caller);
else
hdr = (__ptr_t) realloc (ptr, size);
__free_hook = tr_freehook;
__malloc_hook = tr_mallochook;
__realloc_hook = tr_reallochook;
tr_where (caller);
if (hdr == NULL)
/* Failed realloc. */
fprintf (mallstream, "! %p %#lx\n", ptr, (unsigned long int) size);
else if (ptr == NULL)
fprintf (mallstream, "+ %p %#lx\n", hdr, (unsigned long int) size);
else
{
fprintf (mallstream, "< %p\n", ptr);
tr_where (caller);
fprintf (mallstream, "> %p %#lx\n", hdr, (unsigned long int) size);
}
__libc_lock_unlock (lock);
if (hdr == mallwatch)
tr_break ();
return hdr;
}
#ifdef _LIBC
/* This function gets called to make sure all memory the library
allocates get freed and so does not irritate the user when studying
the mtrace output. */
static void
release_libc_mem (void)
{
/* Only call the free function if we still are running in mtrace mode. */
if (mallstream != NULL)
__libc_freeres ();
}
#endif
/* 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 ()
{
#ifdef _LIBC
static int added_atexit_handler;
#endif
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)
{
/* Make sure we close the file descriptor on exec. */
int flags = __fcntl (fileno (mallstream), F_GETFD, 0);
if (flags >= 0)
{
flags |= FD_CLOEXEC;
__fcntl (fileno (mallstream), F_SETFD, flags);
}
/* Be sure it doesn't malloc its buffer! */
setvbuf (mallstream, malloc_trace_buffer, _IOFBF, TRACE_BUFFER_SIZE);
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;
#ifdef _LIBC
if (!added_atexit_handler)
{
extern void *__dso_handle __attribute__ ((__weak__));
added_atexit_handler = 1;
__cxa_atexit ((void (*) (void *)) release_libc_mem, NULL,
&__dso_handle ? __dso_handle : NULL);
}
#endif
}
}
}
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;
}