Tutorial on debugging with an alternate loader

[Ryan Arnold]

On Thu, Apr 16, 2009 at 11:32 AM, Daniel De La Zerda
<ddelazerda007@yahoo.com> wrote:
> set environment C -E -x c-header
> break _dl_main_dispatch
> run --library-path
> /home/devel/src/rpm/BUILD/glibc-2.4-copy/my-glibc-build:\
> /home/devel/src/rpm/BUILD/glibc-2.4-copy/my-glibc-build/nptl:\
> /home/devel/src/rpm/BUILD/glibc-2.4-copy/my-glibc-build/math:\
> /home/devel/src/rpm/BUILD/glibc-2.4-copy/my-glibc-build/elf:\
> /home/devel/src/rpm/BUILD/glibc-2.4-copy/my-glibc-build/dlfcn:\
> /home/devel/src/rpm/BUILD/glibc-2.4-copy/my-glibc-build/nss:\
> /home/devel/src/rpm/BUILD/glibc-2.4-copy/my-glibc-build/nis:\
> /home/devel/src/rpm/BUILD/glibc-2.4-copy/my-glibc-build/rt:\
> /home/devel/src/rpm/BUILD/glibc-2.4-copy/my-glibc-build/resolv:\
> /home/devel/src/rpm/BUILD/glibc-2.4-copy/my-glibc-build/crypt:\
> /home/devel/src/rpm/BUILD/glibc-2.4-copy/my-glibc-build/nptl:\
> /home/devel/src/rpm/BUILD/glibc-2.4-copy/my-glibc-build/nptl_db \
> /home/devel/src/rpm/BUILD/test/minicond_clock_test
>
> minicond_clock_test is the executable that I want to debug.
>
> When I run the bash script above I get the following error:
>
> "-x: error while loading shared libraries: -x: cannot open shared object file: No such file or directory"
>
> This is strange because I did an "ls" on every path of the bash script and their are all valid paths. I don't know what else could it be. If you need more information, I will be glad to provide.
>
> Thank you for your time,
>
> Daniel

One problem I see right away is with '_dl_main_dispatch'.  That symbol
isn't available on x86[-64] so you'll have to find somewhere else to
break.

With regard to -x, is this error actually referring to the gdb
environment -x or the gdb invocation?  Perhaps older versions of gdb
don't support -x?

Ryan