Re: prelink ok?

["tong changda" <tongcd at hotmail dot com>]

Thanks
All I know documents about prelink is man and following link,
http://www.gentoo.org/doc/en/prelink-howto.xml, Seems not enough to solve 
my question.

Seem I got your meaning UND is left for purpose for when prelinking can't 
be used, exec and libs still works.

three questions remains:
1) I judge prelink works is look at /proc/pid/maps address conforms, Is 
this right?
2) I judge if prelink could bootup startup , by calculating the elapse of 
the fork of new process to first line of main(), if the time(symbol 
resolving stage?) is shorten, I could say it works?
3) prelink show undefined non-weak symbols, for I use arm version 
prelink,ldd(can't show non-weak symbol by using ldd -d -r), I tried to use 
readelf to get non-weak symbol, but seen none, Any other ways?

sorry, new to prelink, so many questions.
Thanks you
       tongchangda
> From: Jakub Jelinek <jakub@redhat.com>
> Reply-To: Jakub Jelinek <jakub@redhat.com>
> To: tong changda <tongcd@hotmail.com>
> CC: libc-alpha@sources.redhat.com
> Subject: Re: prelink ok?
> Date: Wed, 15 Jun 2005 07:54:32 +0200
>
> On Wed, Jun 15, 2005 at 11:27:10AM +0800, tong changda wrote:
> > Hello everybody
> > sorry if not proper to ask here
> >
> > I use prelink on arm dynamic library and execute file. prelink -av 
finished
> > without warning, but readelf shows some unexpects:
> >
> > /lib/libavformat.so.1               420b8000-420fb8b8
> > 0x00000001 (NEEDED)                 Shared library: [libc.so.6]
> > .....
> > 57: 420faacc    32 OBJECT  GLOBAL DEFAULT   13 pam_image_format
> > 58: 00000000   252 FUNC    GLOBAL DEFAULT  UND strchr@GLIBC_2.0 (2)
> >
> > our symbol external is left unsolved, but local symbol are solved the
> > address normally,
> > I think after prelink there should be no UND symbol,Did I compile the
> > library the wrong way?
>
> prelink doesn't change undefined symbols in this way.
> All it does is 1) relocate the shared library to a certain fixed address
> 2) apply relocations 3) prepare things for the dynamic linker, so that if
> all libraries and the binary are mapped in the right places and have not
> been changed since prelinking, ld.so can skip all the relocation handling
> and instead just apply some fixups
> The shared libraries must still be usable even when prelinking can't be
> used.  So e.g. the changing of undefined symbols you are expecting
> (why?) certainly must not be done, as otherwise the shared library
> or binary wouldn't be usable when prelinking can't be used.
> Please read prelink's documentation if you want to know more.
>
> 	Jakub

_________________________________________________________________
免费下载 MSN Explorer:   http://explorer.msn.com/lccn/