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". test/jdk/tools/launcher/RunpathTest.java line 27: > 25: * @test > 26: * @bug 7190813 8022719 > 27: * @summary Check for extended RPATHs on Linux Pre-existing but really the restriction to Linux should be via `@requires` not a runtime test. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/18050#discussion_r1508535229
