On Wed, 28 Feb 2024 19:29:13 GMT, Erik Joelsson <er...@openjdk.org> wrote:

> Executables and dynamic libraries on Linux can encode a search path that the 
> dynamic linker will use when looking up library dependencies, generally 
> referred to as an "rpath". In the JDK we use this with the $ORIGIN feature to 
> set search paths relative to the location of the binary itself. Typically 
> executables in the bin/ directory have the rpath "$ORIGIN/../lib" to find 
> libjli.so. Most of the libraries in lib/ have rpath set to just "$ORIGIN" to 
> find each other.
> 
> There are two different types of such rpaths, RPATH and RUNPATH. The former 
> is the earlier incantation but RUNPATH has been around since about 2003 and 
> has been default in prominent Linux distros for a long time, and now also 
> seems to be default in the linker directly from binutils. The toolchain used 
> by Oracle defaulted to RPATH until at least JDK 11, but since then with some 
> toolchain upgrade, the default was flipped to RUNPATH.
> 
> The main (relevant in this case) difference between the two is that RPATH is 
> considered before the LD_LIBRARY_PATH environment variable, while RUNPATH is 
> only considered after LD_LIBRARY_PATH. For libraries that are part of a Linux 
> distribution, letting users, or the system, control and override builtin 
> rpaths with LD_LIBRARY_PATH seems like a reasonable thing to prefer. However, 
> for the JDK, there really is no usecase for having an externally configured 
> LD_LIBRARY_PATH potentially getting in the way of the JDK libraries finding 
> each other correctly. If a user environment sets LD_LIBRARY_PATH, and there 
> is a library in that path with the same name as a JDK library (e.g. libnet.so 
> or some other generically named library) that external library will be loaded 
> instead of the JDK internal library and that is basically guaranteed to break 
> the JDK. There is no supported usecase that I can think of for injecting 
> other versions of such libraries in a JDK distribution.
> 
> I propose that we explicitly configure the JDK build to set RPATH instead of 
> RUNPATH for Linux binaries. This is done with the linker flag 
> "--disable-new-dtags".

This pull request has now been integrated.

Changeset: 721bfee5
Author:    Erik Joelsson <er...@openjdk.org>
URL:       
https://git.openjdk.org/jdk/commit/721bfee53af5bc2e2d67eebc7b82f09a642d5309
Stats:     22 lines in 2 files changed: 8 ins; 3 del; 11 mod

8326891: Prefer RPATH over RUNPATH for $ORIGIN rpaths in internal JDK binaries

Reviewed-by: ihse, dholmes

-------------

PR: https://git.openjdk.org/jdk/pull/18050

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