[PATCH] Fix dladdr return value when cannot find symbol

Carmelo AMOROSO carmelo.amoroso at st.com
Wed Jan 9 15:48:31 UTC 2008

Mike Frysinger wrote:
> On Wednesday 12 December 2007, Carmelo AMOROSO wrote:
>> while running more tests on this (indeed never used dladdr in the past),
> which tests ?  our dl tests certainly dont have the coverage anywhere close to  
> what i wish they did ...
> -mike
based on  the patch from Nickolai, here you can find a comprehensive 
patch to fix
dladdr function.

With the current implementation, the invocation of dladdr((void *) 1, 
will fill dlinfo.dli_fname with the name of the application itself and
dlinfo.dli_fbase with 0 (the current value of tpnt->loadaddr for the 
main app).

The patch solves this adding a new field into the struct elf_resolve
named  DL_LOADADDR_TYPE mapaddr.
For shared objects, mapaddr has exactly the same value as loadaddr, 
while for the
main app it contains the address of the first PT_LOAD segmented loaded.

loadaddr will keep it's value and will used exactly as is (as a in 
memory offset
with respect to relative addresses from ELF sections).
While in the DL_ADDR_IN_LOADADDR macro, the new field mapaddr needs to 
be used.

I hope I was clear enough in my explanation ;-)
Any comments are welcome.

-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: dladdr.patch
Url: http://lists.busybox.net/pipermail/uclibc/attachments/20080109/a79aa4fd/attachment-0001.diff 

More information about the uClibc mailing list