Re: Question on Glibc add-ons

[Simon <wei dot guo dot simon at gmail dot com>]

Thanks Siddhesh. That really helps. I will try it.

Siddhesh, all,
I have another question regarding glibc here: In my glibc build
directory, there is a ld.so as well. It appears to me that the new
libc.so can only be interpreted by this ld.so. Is it true?

I am asking since I have following experience:
My new built glibc install dir locates at /mnt/simon/usr. And I have a
test program named testMtrace. To use the new glibc, I export
LD_LIBRARY_PATH to include my new libc directory:
root@lionteeth:/mnt/simon # echo $LD_LIBRARY_PATH
/mnt/simon/usr/lib

When I execute the testMtrace program directly, it reports a segmentation fault:
root@lionteeth:/mnt/simon # ./testMtrace
Segmentation fault
In the above case, the system ld-2.3.6.so will be used.

When I execute the same program with new built ld.so, it will be fine:
root@lionteeth:/mnt/simon # /mnt/simon/usr/lib/ld-2.5.so
/mnt/simon/testMtrace && echo $?
0

1) I don't understand why since the glibc is the same version 2.5 with
the old one using by system.

2) And I am not sure the impact of putting "ld-xx.so" before the
executable, like " /mnt/simon/usr/lib/ld-2.5.so /mnt/simon/testMtrace
". Will there be any potential issues(I noticed some trap utility
won't work on such process, like gdb)?

3) Is it a right way to use LD_LIBRARY_PATH environment variable, in
order to temporarily apply the new glibc to one single
program(testMtrace)?  Is there a better choice?

Thanks,
Simon

2013/11/26 Siddhesh Poyarekar <siddhesh.poyarekar@gmail.com>:
> On 26 November 2013 08:51, Simon <wei.guo.simon@gmail.com> wrote:
>> As can be seen, there missed following 2 add-ons:
>>         The C stubs add-on version 2.1.2.
>>         RT using linux kernel aio
>>
>> I had searched the glibc ftp site and googled, but no luck to find
>> tar-balls for these 2 missed add-ons. Can someone help to suggest
>> where I can get those 2 add-ons?
>
> They are present in the glibc source rpm on RHEL or Fedora.  They have
> not been forward-ported to upstream.  If you want a repository with
> that code, then look at the fedora/* branches on the glibc repository.
>
> Siddhesh
> --
> http://siddhesh.in