This package contains my shared, a.out and ELF, dynamic linkers (ld.so
and ld-linux.so), dynamic linker library (libdl.so) and utilities
(ldconfig and ldd) for Linux.

The dynamic linkers, ld.so (a.out) and ld-linux.so (ELF), are used to
bootstrap programs and load shared libraries at startup.  The dynamic
linker library is used to dynamically load ELF shared libraries after
a program is running.  Ldconfig is used to automatically update the
symbolic links to shared libraries and build the cache file used by
the dynamic linkers.  Ldd is used to list the shared libraries used by
a program.

Please see the included manual pages for further details.

To install, simply run "sh instldso.sh" as root.  Ready-to-go versions
of all end-products are provided so nothing should need to be compiled
or linked.

ELF versions of gcc, binutils and libc are now required to compile
almost everything, including ld.so.  A.out versions are only used to
compile the very simple a.out test programs.  If you have an all ELF
system and don't want a.out support, set the value of AOUT_SUPPORT in
Config.mk to false.  Please note that an optimization level of O2 or
higher must be used to compile ld-linux.so due the use of inline
functions.

Notable contributors to this package include Eric Youngdale, Peter
MacDonald, Hongjiu Lu, Linus Torvalds, Lars Wirzenius, Mitch D'Souza,
Rik Faith, Andreas Schwab and Adam Richter (not necessarily in that
order).

Changes in version 1.8.5:

	Fixed a bug in ld.so introduced in the previous changes.

Changes in version 1.8.4:

	Changed ldconfig to completely ignore symbolic links.

	Changed ldconfig to issue the warning concerning an
	inconsistent soname in non-verbose mode.

	Changed ld-linux.so back to not keep ld.so.cache mapped
	at all times.

	Changed Debian packaging to compress man pages, strip all
	binaries (Bug#5125) and include a shlibs file.

Changes in version 1.8.3:

	Changed ld-linux.so to process LD_PRELOAD before
	/etc/ld.so.preload.

	Fixed a Debian packaging problem where libdl might not
	be available if other packages were upgraded at the same
	time (Debian Bug#4728).

	Changed ldd to always exit with status 1 if any errors
	occur (Debian Bug#4188).

	Fixed some minor problems in instldso.sh (Mike Castle and
	Wolfgang Franke).

	Changed ldconfig to issue a warning in verbose mode when 
	skipping a library because the soname doesn't match.

	More sparc fixes (Miguel de Icaza).

	Don't link with -N when building ld.so (Alan Modra).

	Changed ld-linux.so to better support position-dependant
	libraries (NIIBE Yutaka).

Changes in version 1.8.2:

	Added a texinfo file for ld.so and libdl (Michael 
	Deutschmann).

	Minor sparc and installation changes (Elliot Lee).

	Added multiple architecture support for Debian (Leland
	Lucius).

	Changed libdl to better support RTLD_NEXT (Eric 
	Youngdale).  Note: the exact meaning of ETLD_NEXT is 
	still not clear in all cases.

	Removed some libc dependencies from libdl.  Still need
	to remove malloc and free.

Changes in version 1.8.1:

	Changed ld.so to be compiled as ELF.  This also means
	that ELF support is now required.  A.out support is 
	still optional.

	Changed ld-linux.so and libdl.so to use the rpath in the 
	executable instead of in the invoking shared library.

	More m68k fixes (Andreas Schwab).

	Various sparc fixes (Miguel de Icaza).

	Changed ldcnnfig to ignore libraries ending in '~'.

	Changed ldconfig to allow alternative conf and cache 
	files to be specified on the command-line.

	Changed libdl.so to work when dlsym is passed a NULL
	handle pointer.

Changes in version 1.8.0:

	Changed ld-linux.so to be more liberal when checking to
	see if a library is already loaded.  This should avoid
	the duplicate loading problem for programs linkeed with
	the -rpath option.

	Various m68k fixes (Andreas Schwab).

	Changed ld.so to only use LD_AOUT_LIBRARY_PATH and
	LD_AOUT_PRELOAD and ld-linux.so to only use 
	LD_LIBRARY_PATH and LD_PRELOAD.  LD_ELF_LIBRARY_PATH
	and LD_ELF_PRELOAD are no longer supported.

	Changed ld-linux.so to allow debugging of shared and
	dynamically loaded libraries (H.J. Lu, Andreas Schwab).

	Changed ld-linux.so to preload ELF shared libraries 
	listed in /etc/ld.so.preload.  This allows secure 
	preloads, even for setuid/setgid programs.

	Changed ld-linux.so to keep ld.so.cache mapped at all
	times.

	Changed ldconfig to allow #-style comments in ld.so.conf.

	Removed various compiler warnings (Richard Sladkey and
	David Engel).

	Changed ldd to work on ELF shared libraries.  This may
	need a little more work.

Changes in version 1.7.14:

	Changed ldconfig to recognize ELF shared libraries
	generated by post-2.6 versions of ld (Andreas Schwab).

	Changed ldconfig to not remove stale links that do not
	have a version number since they may be needed by ld.

Changes in version 1.7.13:

	Fixed a problem in ld-linux.so where a program linked
	with a shared library that was not used could result in
	a segmentation fault (H.J. Lu).

Changes in version 1.7.12:

	Fixed a problem in libdl.so where the wrong library
	could be marked as global when RTLD_GLOBAL was used
	(Lars Heete).

	Installed dlfcn.h with libdl.so instead of requiring
	it to be supplied with libc.

	Removed support for libldso.a since it was nearly
	impossible to use anyway.

	Changed ldd to detect when the program being checked
	exited abnormally.

Changes in version 1.7.11:

	Changed ld.so and ld-linux.so to delete all variations
	of LD_PRELOAD and LD_LIBRARY_PATH for set[ug]id programs,
	This makes it harder for broken set[ug]id programs to be
	compromised.

	Fixed a problem in libdl.so where dlsym would not accept
	the handle returned from dlopen(0, *).

Changes in version 1.7.10:

	Changed ld-linux.so and libdl.so to support RTLD_GLOBAL
	(Eric Youngdale).

Changes in version 1.7.9:

	Fixed a problem in ld-linux.so in detecting when the 
	new user/group information is provided by the kernel.

	Fixed a problem in ld-linux.so where a buffer could be
	overflowed if a large number of libraries were loaded
	(Thomas Moore).

Changes in version 1.7.8:

	Changed the Makefiles and install scripts to support 
	a.out- and ELF-only configurations.

	Changed ld-linux.so to use the user/group information
	provided by linux 1.3.23+ instead of making syscalls
	to get it.

	Changed libdl.so to support RTLD_NEXT (Glenn Fowler).

	Changed libdl.so to only execute the fini sections
	instead of completely closing libraries at exit (Glenn
	Fowler).

	Changed ld.so and ld-linux.so to print the required
	cache version when a mismatch is detected.

	Changed ld-linux.so to not require on /dev/zero (Ralph
	Loader).

	Minor m68k cleanups (Andreas Schwab).

Changes in version 1.7.7:

	Fixed problems compiling with recent 1.3.x kernels.

	Changed ld-linux.so to not use MAP_DENYWRITE until the
	permission issue regarding it is resolved.

Changes in version 1.7.6:

	Fixed a bug in ld-linux.so dealing with a zero-length
	LD_{ELF_}PRELOAD.

	Changed ld.so and ld-linux.so to truncate all variations
	of LD_PRELOAD and LD_LIBRARY_PATH for set[ug]id programs.

Changes in version 1.7.5:

	Changed ldconfig to recognize libraries without any
	version number (eg. libXYZ.so).

	Changed ldconfig to not generate a corrupt cache when
	the disk is full or other write errors occur.

	Changed ld-linux.so to map files with MAP_DENYWRITE to
	keep them from being changed while the file is in use
	(Rick Sladkey).

	Changed libdl to not overwrite the scope pointer of a 
	library if it was already loaded (H.J. Lu).

	Changed ld-linux.so so gdb can be used on constructors
	(Eric Youngdale).

	Changed ldconfig to ignore ELF libraries where the soname
	does not match the file name on the assumption that it is
	a used at compile-time (eg. libcurses.so -> libncruses.so).

Changes in version 1.7.4:

	Changed ld-linux.so and libdl to use the appropriate
	rpaths when searching for shared libraries (Eric
	Youngdale).

	Changed ld-linux.so to search rpath before using the
	cache.  This more closely conforms to the IBCS standard.

Changes in version 1.7.3:

	Changed ld-linux.so to only print a library name the
	first time it is loaded when run from ldd.

	Fixed a bug in ldconfig where an invalid cache could be
	generated if a directory was specified multiple times in
	ld.so.conf.

	Changed ld-linux.so so it will return the address of a
	weak symbol when called from dlsym in libdl (Eric 
	Youngdale.

Changes in version 1.7.2:

	Changed libdl.so again to fix the undefined foobar
	problem.

Changes in version 1.7.1:

	Changed libdl so it will compile at optimization level
	O3 or higher.

	Changed ldconfig to always create the cache file with 
	mode 644.

	Changed ldconfig to not ingore valid symlinks.

	Changed ldconfig to use the library name as the soname 
	for ELF libraries that do not have an soname entry.

	Changed ld-linux.so to print the actual, requested library
	name at the time it is loaded instead of trying to figure
	it out after the fact.

Changes in version 1.7.0:

	Changed ldconfig to read the actual soname from the image
	for ELF libraries and make it available to ld-linux.so.  
	The soname for DLL libraries is still determined by
	truncating the minor numbers from the image file name.

	Changed ldconfig to no longer support the undocumented
	sort options.

	Changed ld.so to require a valid cache to find libraries
	in directories specified in ld.so.conf.  /usr/lib and /lib
	are still searched as a last resort.  Ld-linux.so already
	operated this way.

	Fixed a bug in libldso.a where the arguments to
	shared_loader were not parsed correctly (Wolfram Gloger).

	Added support for RELA-style relocations under Linux/68k
	(Andreas Schwab).

	Changed ld-linux.so to only map the cache once for all
	libraries instead of individually for each library.

	Changed ld-linux.so continue searching the cache instead of
	giving up when failing to load the first entry found.

	Changed ld-linux.so to produce output similar to ld.so when
	run from ldd or when errors occur.

Changes in version 1.6.7:

	Changed the install scripts to make sure that ld.so and
	ld-linux.so are always usable.

	Added support for Linux/Sparc (Eric Youngdale).

	Added support for Linux/68k (Andreas Schwab).

	Fixed various bugs in ld-linux.so dealing with closing
	files, unmapping memory, dereferencing NULL pointers and 
	printing library names (David Engel, Eric Youngdale and 
	Andreas Schwab).

	Replaced the manual page for libdl with a freely
	distributable one (Adam Richter).

	Fixed a bug in ld-linux.so where LD_LIBRARY_PATH and
	LD_PRELOAD were not cleared for setuid/setgid programs.

	Fixed a bug in libdl where dlsym would not return the
	correct address of a symbol if it was redefined in another
	library (Oleg Kibirev).

	Changed ld-linux.so to use the following order to search 
	for libraries:  LD_{ELF_}LIBRARY_PATH, ld.so.cache, rpath, 
	/usr/lib and /lib.

	Changed ld-linux.so to not needlessly allocate memory when
	using ld.so.cache.

Changes in version 1.6.6:

	Changed ldconfig to not warn about removing stale links
	unless the -v option is specified.

	Added manual pages for libdl (from FreeBSD/Sun)

	Fixed a bug in ld.so dealing with preloading of objects
	generated by recent versions of ld (Mitch D'Souza).

	Fixed bugs in ldd where some errors were either not
	detected or not printed.

	Fixed a bug in ld-linux.so where the trailing nul in a
	library name was not being copied (Owen Taylor).

Changes in version 1.6.5:

	Changed ldconfig to remove stale symbolic links.

	Added debug hooks in ld-linux.so and libdl.so to be used 
	by a future version of gdb (Eric Youngdale).

Changes in version 1.6.4:

	Change ld-linux.so to print on stdout instead of stderr
	when run from ldd.

	Added support for Debian GNU/Linux packaging.

Changes in version 1.6.3:

	Fixed a bug in libdl when closing a library (H.J. Lu).

Changes in version 1.6.2:

	Changed the error message printed by ldd when a file is
	not a.out or ELF.  It used to only list a.out formats.

	Changed ldconfig to no longer cache and set up links for
	ld-linux.so.

	Changed ld-linux.so and libdl to not conflict with upcoming
	changes in kernel header files.

	Changed ld-linux.so to not print preloaded libraries.

Changes in version 1.6.1:

	Updated the installation script.

	Changed ld.so and ld-linux.so to look for LD_AOUT_PRELOAD
	and LD_ELF_PRELOAD, respectively, before LD_PRELOAD.

	Changed ld.so and ld-linux.so to use LD_AOUT_LIBRARY_PATH
	and LD_ELF_LIBRARY_PATH, respectively, instead of
	AOUT_LD_LIBRARY_PATH and ELF_LD_LIBRARY_PATH.

Changes in version 1.6.0:

	Changed ldconfig to process libraries which do not have
	a minor version or patch level number.

	Incorporated ld-linux.so and libdl.so.

	Changed ld.so and ld-linux.so to not miss entries in the
	cache when the fully qualified library is requested.

	Changed ldconfig to use stdout instead of stderr when
	printing the cache.

Changes in version 1.5.3:

	LD_PRELOAD enhancements (Tristan Gigold).

	LD_PRELOAD patch for linux-68k (Andreas Schwab).

Changes in version 1.5.2:

	More ELF changes (Mitch D'Souza).

	Changed ldconfig to also update the link for ld-linux.so.

Changes in version 1.5.1:

	More ELF and LD_PRELOAD changes (Mitch D'Souza).

Changes in version 1.5.0:

	Chnaged all executables to QMAGIC (Mitch D'Souza and Rick
	Sladkey).

	Added preliminary support for ELF to ldd and ldconfig (Eric 
	Youndale and H.J. Lu).

	Added support for LD_PRELOAD to ld.so (Mitch D'Souza).

	Removed the "advertising" clause from the copyright notices
	in all source files.

Changes in version 1.4.4:

	Changed ldconfig to support QMAGIC libraries.

	Fixed a bug in ld.so where some of the error messages had
	transposed arguments.

Changes in version 1.4.3:

	Fixed an obscure bug in ld.so where an index was not being
	incremented when a library was not found using the cache.

Changes in version 1.4.2:

	Changed ldconfig to issue a warning and continue instead
	of an error and exiting when a link can't be updated.  
	This is useful when some libraries are imported on read-
	only file systems, such as an NFS mounted /usr.

	Changed ld.so to be more robust in searching for libraries.
	A library is not considered found unless it can actually be
	loaded.  If a library is not found using the cache, the
	standard directories are searched as in pre-cache versions.

Changes in version 1.4.1:

	Fixed minor Makefile problems.

	Added support for linux-68k.

	Fixed a bug in ld.so where libraries with absolute paths
	were not handled correctly.

	Changed ld.so to ignore the directory in the names of
	shared libraries by default.  This allows older libraries
	with absolute paths, such as the XView libraries, to take
	advantage of the cache support.

	Added a minimal usage message to ldconfig.

Changes in version 1.4:

	Fixed bug in ld.so where minor version numbers were not
	reported correctly when a minor version incompatibility
	was found.

	Fixed bug in ldconfig where libraries with subversion
	numbers greater than 9 were not compared correctly.

	Added Mitch D'Souza's support for suppressing warning
	messages from ld.so about minor version incompatibilities.

	Added Mitch D'Souza's support for using a cache to speed
	up searching for libraries in the standard directories.

	Added Mitch D'Souza's support for a debugging version of
	ld.so.  Link with -lldso if you think you are experiencing
	dynamic linker problems.

Changes in version 1.3:

	Added support for libraries using absolute pathnames.  If I
	had known that the XView libraries used them, I would have
	added this earlier.

	Fixed a bug handling old libraries using a pathname beginning
	with '/' or '/lib/'.

Changes in version 1.2a:

	Fixed a minor bug in ldd which caused all files, specifically
	scripts, to be recognized as binaries.  Thanks to Olaf Flebbe
	for reporting it.

David Engel
david@ods.com
