src/libexec/rtld-elf/rtld.1, branch releng/10.2

Import the DragonFly BSD commit 4f0bc915b65fcf5a23214f6d221d65c80be68ad4

2012-07-15T10:53:48Z

by John Marino , with the following (edited) commit message Date: Sat, 24 Mar 2012 06:40:50 +0100 Subject: [PATCH 1/1] rtld: Implement DT_RUNPATH and -z nodefaultlib DT_RUNPATH is incorrectly being considered as an alias of DT_RPATH. The purpose of DT_RUNPATH is to have two different types of rpath: one that can be overridden by the environment variable LD_LIBRARY_PATH and one that can't. With the currently implementation, LD_LIBRARY_PATH will always trump any embedded rpath or runpath tags. Current path search order by rtld: ================================== LD_LIBRARY_PATH DT_RPATH / DT_RUNPATH (always the same) ldconfig hints file (default: /var/run/ld-elf.so.hints) /usr/lib New path search order by rtld: ============================== DT_RPATH of the calling object if no DT_RUNPATH DT_RPATH of the main binary if no DT_RUNPATH and binary isn't calling obj LD_LIBRARY_PATH DT_RUNPATH ldconfig hints file /usr/lib The new path search matches how the linux runtime loader works. The other major added feature is support for linker flag "-z nodefaultlib". When this flag is passed to the linker, rtld will skip all references to the standard library search path ("/usr/lib" in this case but it could handle more color delimited paths) except in DT_RPATH and DT_RUNPATH. New path search order by rtld with -z nodefaultlib flag set: ============================================================ DT_RPATH of the calling object if no DT_RUNPATH DT_RPATH of the main binary if no DT_RUNPATH and binary isn't calling obj LD_LIBRARY_PATH DT_RUNPATH ldconfig hints file (skips all references to /usr/lib) FreeBSD notes: - we fixed some bugs which were submitted to DragonFly and merged there as commit 1ff8a2bd3eb6e5587174c6a983303ea3a79e0002; - we added LD_LIBRARY_PATH_RPATH environment variable to switch to the previous behaviour of considering DT_RPATH a synonym for DT_RUNPATH; - the FreeBSD default search path is /lib:/usr/lib and not /usr/lib. Reviewed by: kan MFC after: 1 month MFC note: flip the ld_library_path_rpath default value for stable/9

Implement support for ELF filters in rtld. Both normal and auxillary

2010-12-25T08:51:20Z

filters are implemented. Filtees are loaded on demand, unless LD_LOADFLTR environment variable is set or -z loadfltr was specified during the linking. This forces rtld to upgrade read-locked rtld_bind_lock to write lock when it encounters an object with filter during symbol lookup. Consolidate common arguments of the symbol lookup functions in the SymLook structure. Track the state of the rtld locks in the RtldLockState structure. Pass local RtldLockState through the rtld symbol lookup calls to allow lock upgrades. Reviewed by: kan Tested by: Mykola Dzham , nwhitehorn (powerpc)

mdoc: drop redundant .Pp and .LP calls

2010-10-08T12:40:16Z
They have no effect when coming in pairs, or before .Bl/.Bd

Document RTLD_NODELETE, -z nodelete and -z origin support.

2009-04-01T14:38:20Z

Support for a new environment variable, LD_ELF_HINTS_PATH for overriding

2009-03-23T16:49:00Z
the rtld hints file. This environment variable would be unset if the process is considered as tainted with setuid/setgid. This feature gives a convenient way of using a custom set of shared library that is not located in the default location and switch back. Feature requested by: iXsystems Original patch by: John Hixson MFC after: 2 weeks

Make the meaning of the %A format specifier, as passed to

2008-05-15T10:47:14Z
LD_TRACE_LOADED_OBJECTS_FMT[12], more obvious for users like me.

Update the man page to reflect that certain variables will be unset in

2007-05-17T19:14:25Z
the case that the program is set-user-ID or set-group-ID. Add missing annotations for LIBMAP and LIBMAP_DISABLE.

Remove %m formatter, it's ifdef 0'ed in the code from the very beginning

2007-05-12T12:26:25Z
MFC after: 1 week

Expand documentation for LD_TRACE_LOADED_OBJECTS_FMT? variables

2007-05-12T12:24:49Z
PR: docs/66265 (inspired by) Submitted by: Michel Lavondes MFC after: 1 week

Document LD_UTRACE.

2007-01-23T22:38:39Z
MFC after: 3 days