On Thu, Dec 13, 2012 at 12:03 AM, John Reiser <jrei...@bitwagon.com> wrote: >> calloc -> _vgr10070ZU_libcZdsoZa_calloc >> >> But after "moving" the start of calloc to orig_calloc, we want: >> >> orig_calloc -> _vgr10070ZU_libcZdsoZa_calloc > > You control orig_calloc, so what is stopping you?
By reassigning redirections I really meant replacing them by another one. True, leaving the resolution of _vgr10070ZU_libcZdsoZa_calloc aside, l could indeed add that redirection myself. However, I think it doesn't cut it: As I understand it, even with that extra redirection, the initial "calloc -> _vgr10070ZU_libcZdsoZa_calloc" redirection would still be active, breaking my hijacking mechanism, which would render my code unusable. Remember that I expect calloc_hijacker to be called instead of calloc. With the initial redirection still in place, _vgr10070ZU_libcZdsoZa_calloc would be called instead. > The routine calloc_hijacker could check whether the instruction layout > remains the same as the first time, deduce that valgrind is active, > and re-arrange the code further. (Remember to sync the Icache; > on x86 any backwards branch suffices, but on other architectures > a system call is necessary.) I might be missing something, but I don't see how calloc_hijacker would be called at all if "calloc -> _vgr10070ZU_libcZdsoZa_calloc" is still in place. After skimming the sources of Valgrind I see that some functions are replaced and not wrapped (with no possibility to access the original function) and calloc seems to be one of them. Even if calloc was wrapped, it is up to the wrapped to call the original function. ------------------------------------------------------------------------------ LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial Remotely access PCs and mobile devices and provide instant support Improve your efficiency, and focus on delivering more value-add services Discover what IT Professionals Know. Rescue delivers http://p.sf.net/sfu/logmein_12329d2d _______________________________________________ Valgrind-users mailing list Valgrind-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/valgrind-users
