From: "Yann E. MORIN" <yann.morin.1998@free.fr>
To: crossgcc@sourceware.org
Cc: Mirko Banchi <mk.banchi@gmail.com>, Zvi Vered <veredz72@gmail.com>
Subject: Re: How can I modify the source of new,malloc
Date: Tue, 26 Jun 2012 20:14:00 -0000 [thread overview]
Message-ID: <201206262214.37680.yann.morin.1998@free.fr> (raw)
In-Reply-To: <8347C635-3CB0-4967-8BCB-5AA28FC204B1@gmail.com>
Zvi, Mirko, All,
[Please, do not top-post...]
On Tuesday 26 June 2012 00:28:09 Mirko Banchi wrote:
> Il giorno 25/giu/2012, alle ore 23.55, Zvi Vered <veredz72@gmail.com>
> ha scritto:
> > I have a huge application (not written by me).
> > I want to track all places where a dynamic allocation is done.
> > Is there an alternative to my way ?
> You could write your own shared object with your malloc implementation
> and use LD_PRELOAD var.
As Mirko suggested, I'd use a loader trick to pre-load a shared lib that
overrides the malloc() and free() functions. Something like (untested!):
void* malloc( size_t size )
{
static void* real_malloc;
if( ! real_malloc ) {
real_malloc = dlsym( RTLD_NEXT, "malloc" );
if( ! real_malloc ) {
panic_and_exit();
}
}
fprintf( stderr, "Allocating %d bytes\n", size );
return real_malloc( size );
}
Then, replacing printf with calls to backtrace(3) and backtrace_symbols_fd(3),
you can know the caller (function, offset), if you have the debug symbols in
the binaries (libs and executable), in which case you can post-process that
to find the actual file, function and line at which the call to malloc is
made.
(Note: do not use backtrace_symbols(3), as it calls malloc! So you have
to use backtrace_symbols_fd(3)).
Then, you can write such wrappers to free(3) and so on...
Note however, that if you can recompile your application, you may want to
link with a library like DUMA or dmalloc instead of using the above trick.
http://duma.sourceforge.net/
http://dmalloc.com/
Which can be installed in the toolshain's sysroot by crosstool-NG ( I leave
it up to you to find in which sub-menu these libs' options live! ;-) )
Cheers,
Yann E. MORIN.
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next prev parent reply other threads:[~2012-06-26 20:14 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-25 21:55 Zvi Vered
2012-06-25 22:28 ` Mirko Banchi
2012-06-26 20:14 ` Yann E. MORIN [this message]
2012-06-26 20:21 ` Joel Sherrill
2012-06-27 9:17 ` Eric Doenges
2012-06-27 9:51 ` Eric Doenges
2012-06-27 20:05 ` Yann E. MORIN
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