Run (some?) ELF constructors after applying RELRO protection

[Florian Weimer]

I think it would be a nice addition to the toolchain if it were possible 
to programatically initialize data in the RELRO section.  We do this in 
glibc, but I don't think this is currently supported for general use.

One important application is to allocate a memory region with mmap, on 
which protection flags can be changed as needed.  This way, the 
application can have a read-only path to its own configuration data, for 
example.

Do you think this would be worthwhile to implement?  Any suggestions how 
we should do it, without needing binutils/GCC/glibc updates?

Thanks,
Florian