svn commit: r362152 - head/usr.bin/ldd

[John Baldwin]

On 6/13/20 11:21 AM, Konstantin Belousov wrote:
> Author: kib
> Date: Sat Jun 13 18:21:31 2020
> New Revision: 362152
> URL: https://svnweb.freebsd.org/changeset/base/362152
> 
> Log:
>   Fix ldd for PIE binaries after rtld stopped accepting binaries for dlopen.
>   
>   ldd proclaims ET_DYN objects as shared libraries and tries to
>   dlopen(RTLD_TRACE) them to get dependencies. Since PIE binaries are
>   ET_DYN | DF_1_PIE, refusal to dlopen such binaries breaks ldd.
>   
>   Fix it by reading and parsing dynamic segment looking for DF_FLAG_1
>   and taking DF_1_PIE into account when deciding between binary and
>   library.

Hmmm, I have an alternate patch for this that instead depends on the
present of PT_INTERP (since we already look at program headers) to
determine PIE vs not-PIE.  This has the advantage of working for older
binaries since DF_1_PIE is relatively recent.  (I had also changed it to
use libelf to reduce code duplication for the 32-bit compat stuff, but
it was pending on getting the branding sorted out since it still doesn't
fully work for RISC-V and aarch64 shared libraries until they are
branded as the patches also look at notes sections to check for the
FreeBSD ABI note tag to decide if a shared library is a FreeBSD one that
can be passed to dlopen()).

-- 
John Baldwin