Public bug reported:

$ lsb_release -rd
Description:    Ubuntu 13.10
Release:        13.10

$ uname -a
Linux mhassert 3.11.0-13-generic #20-Ubuntu SMP Wed Oct 23 07:38:26 UTC 2013 
x86_64 x86_64 x86_64 GNU/Linux

$gcc -dumpversion
4.8

$ ld -v
GNU ld (GNU Binutils for Ubuntu) 2.23.52.20130913

$ LC_ALL=C apt-cache policy libc-bin
libc-bin:
  Installed: 2.17-93ubuntu4

* What you expected to happen
Binaries with DT_RPATH or DT_RUNPATH behaving identical in the absence of 
LD_LIBRARY_PATH

* What happened instead
DT_RUNPATH not searched for transitive dependencies.


When running a binary that depends on custom libraries which in turn depend on 
custom libraries, hard-coded search paths in DT_RUNPATH behave differently from 
those in DT_RPATH.
Paths in DT_RPATH are being considered for everything that is dynamically 
loaded, even dependencies of dependencies. Paths in DT_RUNPATH seem being 
considered only for direct dependencies of the binary.

Searching the web I think that the one and only difference between
DT_RPATH and DT_RUNPATH should be that DT_RPATH is considered _before_
LD_LIBRARY_PATH and DT_RUNPATH _afterwards_. In the absence of
LD_LIBRARY_PATH there should be no difference at all.

I stumbled upon this problem when switching from "ld" to "gold" for the
linker. The default for ld on Ubuntu 13.10 is "--disable-new-dtags"
while the default for gold is "--enable-new-dtags". Therefore ld
produces binaries with DT_RPATH and gold ones with DT_RUNPATH.

In the attached minimal example
- the binaries rpath and runpath both depend on libb but not directly on liba.
- libb depends on liba.
- liba and libb are linked without any hard-coded library paths.
- rpath and runpath are linked with  hard-coded library paths for both liba and 
libb
- rpath is linked with --disable-new-dtags (producing DT_RPATH)
- rpath is linked with --enable-new-dtags (producing DT_RUNPATH)

To test, please run make all and observe how "rpath" works while
"runpath" fails to find liba at runtime.

** Affects: eglibc (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: dynamic hardcoded library linker paths rpath runpath

** Attachment added: "minimal example"
   
https://bugs.launchpad.net/bugs/1253638/+attachment/3914081/+files/linker_bug.tar.gz

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https://bugs.launchpad.net/bugs/1253638

Title:
  dynamic linker does not use DT_RUNPATH for transitive dependencies

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