[Ltrace-devel] can't read ELF entry

Petr Machata pmachata at redhat.com
Wed Nov 2 12:11:02 UTC 2011

Imre Deak <imre.deak at gmail.com> writes:

> tracing some programs in Ubuntu Oneiric/x86_64 like totem or firefox
> gives no library call trace. I got the same result with the ltrace version
> from git:

For firefox, the case might be that there is a wrapper script in effect.
Ltrace could be able to handle this.  If opening the ELF file failed,
we'd have a look if the file starts with shebang, and do what kernel
does.  But currently this isn't written.

Note that firefox is a heavily threaded application and stock ltrace
will soon fail if it tries tracing that.  There's a monster patch ready
on pmachata/threading for that, but I'm still fixing races in that, so I
don't want to merge it just yet.

For totem, I'm not sure what's going wrong.  On Fedora, this works, but
when I download the Ubuntu binary, which (mirabile dictu!) actually
works with Fedora libraries, I get the same as you (tracing syscalls
works, but no PLT probes get installed).  I'll take a look at that.


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