Rework ifunc support to address a number of short comings:
- Move to a shared _rtld_call_ifunc for rel and rela architectures
- Architectures using rel format must patch IRELATIVE non-PLT
relocations like RELATIVE in additition to the later ifunc handling
- Consistently record the delta to the end of the relocation group for
non-PLT IRELATIVE relocations

Hidden ifunc is now supported on all ifunc platforms, even when using
-fno-plt. The combination of -fno-plt and relro is broken due to
incorrect GNU ld output though.

branches: 1.14.44;
simplify the logic for compat ld.elf_so and move it here. we now can
find the libc objdir for multiple compat ld.elf_so's, too.

rename LD32DIR to MLIBDIR.

move the defines for RTLD_ARCH_SUBDIR into a sub-sub-makefile so we can
grab these values via reach-over more easily.

branches: 1.11.2;
if LD32DIR is defined:
- look in src/compat/lib/libc for libc_pic.
- define RTLD_ARCH_SUBDIR to "i386" or "sparc" for amd64 and sparc64
builds, respectively
if RTLD_ARCH_SUBDIR is defined, add this path before
RTLD_DEFAULT_LIBRARY_PATH in the default search path.

Explicitly prefix ld(1) options in LDFLAGS with "-Wl," rather than
using the ${LDFLAGS:@F@-Wl,$F@} make substitution because that breaks
if LDFLAGS is already set.

Move common LDFLAGS into Makefile from arch/*/Makefile.inc

Whitespace.

Split the `self' case out of _rtld_relocate_nonplt_objects, into a new function
_rtld_relocate_nonplt_self(), which is called from _rtld_start.
Now we're completely relocated before main() is called.
We also no longer need _GOT_END_, so junk the ld script.

This code assumes that ld.elf_so only contains RELATIVE relocs, but that's
supposed to be the case for -Bsymbolic anyway.

Get rid of RTLD_RELOCATE_SELF on i386.
* Add a ld.so.script that exports _GOT_END_.
* Prebind the GOT in _rtld_start.
* Skip over GOT relocs in _rtld_relocate_nonplt_objects().
This makes debugging work better at least.

Make _rtld_setup_pltgot() a consistent interface on all platforms.

branches: 1.4.2;
Grumble. Put compiler options back into CPPFLAGS for now, since
they're needed to build .S files with the correct PIC options.

XXX Really needs cleanup in <bsd.*.mk> to do this properly.

Don't put compiler options into CPPFLAGS.

Cleanup global variable access so rtld can be self relocating. Also KNF
reloc.c and move md sparc parts to arch/sparc/mdreloc.c
Now we don't need to load at address 0 on the i386 and the mips should be
trivial to fix.

Add i386 bits. Only works with -fpic or -fPIC compiled binaries since
COPY relocations don't work.

simplify the logic for compat ld.elf_so and move it here. we now can
find the libc objdir for multiple compat ld.elf_so's, too.

branches: 1.1.2;
move the defines for RTLD_ARCH_SUBDIR into a sub-sub-makefile so we can
grab these values via reach-over more easily.

Split the `self' case out of _rtld_relocate_nonplt_objects, into a new function
_rtld_relocate_nonplt_self(), which is called from _rtld_start.
Now we're completely relocated before main() is called.
We also no longer need _GOT_END_, so junk the ld script.

This code assumes that ld.elf_so only contains RELATIVE relocs, but that's
supposed to be the case for -Bsymbolic anyway.

Get rid of RTLD_RELOCATE_SELF on i386.
* Add a ld.so.script that exports _GOT_END_.
* Prebind the GOT in _rtld_start.
* Skip over GOT relocs in _rtld_relocate_nonplt_objects().
This makes debugging work better at least.

ld.elf_so/arch/i386: Add ELF references.

Also copy the copyright notice from the file this one was originally
derived from back in 2002.

Create a new header lwp_private.h to contain _lwp_getprivate_fast,
_lwp_gettcb_fast, _lwp_settcb and remove them from mcontext.h, so that:
1. we don't need special hacks to hide them
2. we can include <lwp.h> where needed to get the necessary prototypes
without redefining them locally.

Undo previous lwp.h change

Split __lwp_getprivate_fast and __lwp_*tcb from mcontext.h into a separate
lwp.h file.

ld.elf_so(1): Nix trailing whitespace.

No functional change intended.

branches: 1.43.2;
Avoid using uninitialized variable "symnum" when building with DEBUG
enabled by borrowing the rdbg_symname() macro from arch/x86_64.

Fix interactions of initial-exec TLS model and dlopen

(1) If an initial-exec relocation was used for a non-local symbol
(i.e. the definition of the symbol is in a different DSO), the
computation of the static TLS offset used the wrong DSO.
This would effectively mean the wrong address was computed
(PR toolchain/50277, PR pkg/57445).

Fix this by forcing the computation of the correct DSO (the one defining
the symbol).

This code uses __UNCONST to avoid the vast interface changes for this
special case.

(2) If symbols from a DSO loaded via dlopen are used with both
global-dynamic/local-dynamic and initial-exec relocations AND
a initial-exec relocation was resolved first in a thread, a split brain
situation could exist where the dynamic relocations would use one memory
block (separate allocation) and the initial-exec relocations the static
per-thread TLS space.

(3) If the initial-exec relocation in (2) is seen after any thread has
already used a GD/LD allocation, bail out. Since IE relocations are used
only in the GOT, this will prevent the dlopen. This is a bit more
aggressive than necessary, but a full blown reference counting doesn't
seem to be justified.

branches: 1.41.4; 1.41.12;
Rework ifunc support to address a number of short comings:
- Move to a shared _rtld_call_ifunc for rel and rela architectures
- Architectures using rel format must patch IRELATIVE non-PLT
relocations like RELATIVE in additition to the later ifunc handling
- Consistently record the delta to the end of the relocation group for
non-PLT IRELATIVE relocations

Hidden ifunc is now supported on all ifunc platforms, even when using
-fno-plt. The combination of -fno-plt and relro is broken due to
incorrect GNU ld output though.

branches: 1.40.2;
init/fini for the main program is handled by crt0.o, so ifunc handling
is skipped right now as it iterates the same list. Don't repeat that
mistake and explicitly take care of it in the dynamic linker.

Add IRELATIVE support for ARM, X86 and PowerPC.

Replace COMBREL with just-in-time check in _rtld_relocate_nonplt_objects.

The COMBREL logic predates thread-safety of the dynamic linker and
breaks the use of shared locks for the common symbol lookup case. It is
unlikely to provide any benefit for lazy binding or PLT lookups, so
provide equivalent functionality in the non-PLT relocation handling loop
by checking if the symbol used by the current relocation is the same as
the one used during the last lookup. No inter-object cachine is done as
it is also unlikely to be benefical.

Testing with Firefox startup on AMD64 shows a small performance gain by
the new method.

branches: 1.37.8;
Remove (now duplicated) target computation.

Add basic support for indirect functions. It allows providing a public
function symbol with an implementation choosen at run time.
Refactor calls to functions by address in ld.elf_so to create temporary
function descriptors on the stack, if the address is not leaked outside.

Limitations:
- no support for initialising static storage with function pointers
- no support for unnamed resolver functions

Inspired by FreeBSD's r228435 by kib@freebsd.org.

branches: 1.35.8;
Add support for R_386_TLS_TPOFF32. This patch was created by
Nick Hudson for PR 47061.

branches: 1.34.4; 1.34.6; 1.34.10;
Add basic locking to ld.elf_so.

Add TLS support for AMD64, i386 and SH3.

This material is based upon work partially supported by
The NetBSD Foundation under a contract with Joerg Sonnenberger.

Reduce header pollution for mdreloc.c. Make Obj_Entry argument of
_rtld_relocate_nonplt_objects non-const in preparation for TLS support.

Wrap a few long lines.

Shut gcc up.

PR/39240: Satoshi Suetake: Don't fail when attempting to resolve weak symbols
when we are doing immediate binding, leave them alone and they will be dealt
with later during lazy binding. From skrll@

Remove trailing \n in calls to _rtld_error: a newline is automatically
added by a call to the function.

Fix const issues (cast const pointers to "const uint8_t *" instead of "caddr_t")

branches: 1.26.4; 1.26.6;
Refactor common code to _rtld_relocate_plt_object to i386 and arm so they
act like the other versions.
In _rtld_bind, if the result is 0, call _rtld_die.
Initialize _rtld_sym_zero.st_value to -_rtld_objself.maprelocbase. Now when
the symbol is resolved, st_value + maprelocbase will equal 0 and the above
check in _rtld_bind will fire and a call to NULL will be avoided.

abort() if we are trying to use an undefined weak symbol from the plt. Remove
check from relocate_plt_object() since we cannot return _rtld_sym_zero anymore.
Code from gimpy.

handle sym_zero like x86_64; other ports might need this too.

branches: 1.23.12;
Remove MD COMBRELOC support since it's now MI.
Enable COMBRELOC for all arches

Coverity CID 923: Avoid NULL deref.

Add __RCSID.

appease gcc -Wuninitialized

branches: 1.19.4;
ANSIfy and de-__P().

Skip the lazy PLT relocation if relocbase==0 (useful if libraries are loaded
at their VMA address).

Remove the `self' args to _rtld_relocate_objects() and
_rtld_relocate_nonplt_objects().

Push the _rtld_bind() interface into MD code -- it's just a trivial wrapper
anyway.

Make immediate binding work again by actually implementing
_rtld_relocate_plt_objects(). Note that this is for i386 only;
any efforts to make it work on other platforms are left to
those who are using them...

Nuke -DRTLD_RELOCATE_SELF and `dodebug' from orbit.

_rtld_bind_start() is not used in MI code, so declare it in the MD code.

Split the `self' case out of _rtld_relocate_nonplt_objects, into a new function
_rtld_relocate_nonplt_self(), which is called from _rtld_start.
Now we're completely relocated before main() is called.
We also no longer need _GOT_END_, so junk the ld script.

This code assumes that ld.elf_so only contains RELATIVE relocs, but that's
supposed to be the case for -Bsymbolic anyway.

Add $NetBSD$.

Get rid of RTLD_RELOCATE_SELF on i386.
* Add a ld.so.script that exports _GOT_END_.
* Prebind the GOT in _rtld_start.
* Skip over GOT relocs in _rtld_relocate_nonplt_objects().
This makes debugging work better at least.

Pass down an additional flag to _rtld_relocate_nonplt_objects() which
indicates whether we're relocating ld.elf_so itself. Use this in some places
rather than hackish tests on `dodebug'. (The Alpha and HPPA `dodebug' tests
were actually noops, because RTLD_RELOCATE_SELF is not set, and therefore
dodebug is always true.)

Introduce a new flag, `isdynamic', which is used to remember whether the
executable was of type ET_DYN. Use this instead of `mainprog' to determine
whether we need to do base-relative fixups of the PLT. (This allows loading
non-relocatable objects, should we desire to do that at some point...)

Re-poison a lot of consts, now that the mark shite is gone.

Split _rtld_relocate_plt_object() into two MD functions:
* _rtld_relocate_plt_lazy() fixes up all the relocs pointing to the PLT. (On
most platforms it just does a simple base-relative fixup; on SPARC it does
nothing.)
* _rtld_relocate_plt_object() does immediate binding for a PLT entry.
The basic gist is that this saves a bit of time on SPARC (where the iteration
through the pltrela table was gratuitous), and a little less time on all other
platforms. A whole lot of #ifdef'ed crap is moved out of reloc.c, too.

NOT tested on: hppa sh x86_64

Partially fix up some debug printf()s that don't need to use defobj.

A few things:
* Pass a symbol number to _rtld_find_symdef(), not a r_info.
* Don't try to do a symbol lookup when we find an unsupported relocation;
instead get the symbol name from the referencing object's strtab.
* Add preliminary support for `-z combreloc'-style startup optimization on
i386, `#ifdef COMBRELOC'.

Rename _rtld_relocate_nonplt_object() to _rtld_relocate_nonplt_objects(),
and push the outer loop into it. This actually shaves a couple % off startup
time at least on PCs.

Split _rtld_relocate_nonplt_object() into separate MD files.

Make _rtld_setup_pltgot() a consistent interface on all platforms.

Build ld.elf_so with -fvisibility=hidden. Exploit this for i386/x86_64
to simplify the assembler code.

Remove clause 3 and 4 from TNF licenses

branches: 1.9.30;
Shorten rtld_start() by 2 instructions or 8 bytes, and make it not use GOT
entries.

We don't need to save quite as many registers in the stub.

Update comments.

Pass the calculated relocation offset down to _rtld().

Split the `self' case out of _rtld_relocate_nonplt_objects, into a new function
_rtld_relocate_nonplt_self(), which is called from _rtld_start.
Now we're completely relocated before main() is called.
We also no longer need _GOT_END_, so junk the ld script.

This code assumes that ld.elf_so only contains RELATIVE relocs, but that's
supposed to be the case for -Bsymbolic anyway.

Get rid of RTLD_RELOCATE_SELF on i386.
* Add a ld.so.script that exports _GOT_END_.
* Prebind the GOT in _rtld_start.
* Skip over GOT relocs in _rtld_relocate_nonplt_objects().
This makes debugging work better at least.

branches: 1.3.12;
Remove unneeded args for rtld (kleink)

Be consistant about the .rtld_start and _rtld_start

Add i386 bits. Only works with -fpic or -fPIC compiled binaries since
COPY relocations don't work.