src/libexec/rtld-elf/amd64, branch releng/10.2

MFC r280816:

2015-04-12T06:45:40Z

Change default visibility for rtld to hidden, on x86.

MFC r270798:

2014-09-12T16:22:01Z

Process STT_GNU_IFUNC when doing non-plt relocations. MFC r270802: Only do the second pass over non-plt relocations when the first pass found IFUNCs. Approved by: re (gjb)

MFC r264481:

2014-04-21T02:55:27Z

Add dwarf annotations to the amd64 _rtld_bind_start to allow debuggers to unwind around the calls from PLT to binder.

Add GNU hash support for rtld.

2012-04-30T13:31:10Z

Based on dragonflybsd support for GNU hash by John Marino Reviewed by: kan Tested by: bapt MFC after: 2 weeks

Fix several problems with our ELF filters implementation.

2012-03-20T13:20:49Z

Do not relocate twice an object which happens to be needed by loaded binary (or dso) and some filtee opened due to symbol resolution when relocating need objects. Record the state of the relocation processing in Obj_Entry and short-circuit relocate_objects() if current object already processed. Do not call constructors for filtees loaded during the early relocation processing before image is initialized enough to run user-provided code. Filtees are loaded using dlopen_object(), which normally performs relocation and initialization. If filtee is lazy-loaded during the relocation of dso needed by the main object, dlopen_object() runs too earlier, when most runtime services are not yet ready. Postpone the constructors call to the time when main binary and depended libraries constructors are run, passing the new flag RTLD_LO_EARLY to dlopen_object(). Symbol lookups callers inform symlook_* functions about early stage of initialization with SYMLOOK_EARLY. Pass flags through all functions participating in object relocation. Use the opportunity and fix flags argument to find_symdef() in arch-specific reloc.c to use proper name SYMLOOK_IN_PLT instead of true, which happen to have the same numeric value. Reported and tested by: theraven Reviewed by: kan MFC after: 2 weeks

Add support for preinit, init and fini arrays. Some ABIs, in

2012-03-11T20:03:09Z

particular on ARM, do require working init arrays. Traditional FreeBSD crt1 calls _init and _fini of the binary, instead of allowing runtime linker to arrange the calls. This was probably done to have the same crt code serve both statically and dynamically linked binaries. Since ABI mandates that first is called preinit array functions, then init, and then init array functions, the init have to be called from rtld now. To provide binary compatibility to old FreeBSD crt1, which calls _init itself, rtld only calls intializers and finalizers for main binary if binary has a note indicating that new crt was used for linking. Add parsing of ELF notes to rtld, and cache p_osrel value since we parsed it anyway. The patch is inspired by init_array support for DragonflyBSD, written by John Marino. Reviewed by: kan Tested by: andrew (arm, previous version), flo (sparc64, previous version) MFC after: 3 weeks

Remove unneeded dtv variable.

2012-01-17T21:55:20Z

It is only assigned and not used at all. The object files stay identical when the variables are removed. Approved by: kib

_rtld_bind() read-locks the bind lock, and possible plt resolution

2011-12-14T16:47:53Z

from the dispatcher would also acquire bind lock in read mode, which is the supported operation. plt is explicitely designed to allow safe multithreaded updates, so the shared lock do not cause problems. The error in r228435 is that it allows read lock acquisition after the write lock for the bind block. If we dlopened the shared object that contains IRELATIVE or jump slot which target is STT_GNU_IFUNC, then possible recursive plt resolve from the dispatcher would cause it. Postpone the resolution for irelative/ifunc right before initializers are called, and drop bind lock around calls to dispatcher. Use initlist to iterate over the objects instead of the ->next, due to drop of the bind lock in iteration. For i386/reloc.c:reloc_iresolve(), fix calculation of the dispatch function address for dso, by taking into account possible non-zero relocbase. MFC after: 3 weeks

Add support for STT_GNU_IFUNC and R_MACHINE_IRELATIVE GNU extensions to

2011-12-12T11:03:14Z

rtld on 386 and amd64. This adds runtime bits neccessary for the use of the dispatch functions from the dynamically-linked executables and shared libraries. To allow use of external references from the dispatch function, resolution of the R_MACHINE_IRESOLVE relocations in PLT is postponed until GOT entries for PLT are prepared, and normal resolution of the GOT entries is finished. Similar to how it is done by GNU, IRELATIVE relocations are resolved in advance, instead of normal lazy handling for PLT. Move the init_pltgot() call before the relocations for the object are processed. MFC after: 3 weeks

- change "is is" to "is" or "it is"

2011-10-16T14:30:28Z

- change "the the" to "the" Approved by: lstewart Approved by: sahil (mentor) MFC after: 3 days