posix/wordexp-test.c used libc-internal.h for PTR_ALIGN_DOWN; similar
to what was done with libc-diag.h, I have split the definitions of
cast_to_integer, ALIGN_UP, ALIGN_DOWN, PTR_ALIGN_UP, and PTR_ALIGN_DOWN
to a new header, libc-pointer-arith.h.
It then occurred to me that the remaining declarations in libc-internal.h
are mostly to do with early initialization, and probably most of the
files including it, even in the core code, don't need it anymore. Indeed,
only 19 files actually need what remains of libc-internal.h. 23 others
need libc-diag.h instead, and 12 need libc-pointer-arith.h instead.
No file needs more than one of them, and 16 don't need any of them!
So, with this patch, libc-internal.h stops including libc-diag.h as
well as losing the pointer arithmetic macros, and all including files
are adjusted.
* include/libc-pointer-arith.h: New file. Define
cast_to_integer, ALIGN_UP, ALIGN_DOWN, PTR_ALIGN_UP, and
PTR_ALIGN_DOWN here.
* include/libc-internal.h: Definitions of above macros
moved from here. Don't include libc-diag.h anymore either.
* posix/wordexp-test.c: Include stdint.h and libc-pointer-arith.h.
Don't include libc-internal.h.
* debug/pcprofile.c, elf/dl-tunables.c, elf/soinit.c, io/openat.c
* io/openat64.c, misc/ptrace.c, nptl/pthread_clock_gettime.c
* nptl/pthread_clock_settime.c, nptl/pthread_cond_common.c
* string/strcoll_l.c, sysdeps/nacl/brk.c
* sysdeps/unix/clock_settime.c
* sysdeps/unix/sysv/linux/i386/get_clockfreq.c
* sysdeps/unix/sysv/linux/ia64/get_clockfreq.c
* sysdeps/unix/sysv/linux/powerpc/get_clockfreq.c
* sysdeps/unix/sysv/linux/sparc/sparc64/get_clockfreq.c:
Don't include libc-internal.h.
* elf/get-dynamic-info.h, iconv/loop.c
* iconvdata/iso-2022-cn-ext.c, locale/weight.h, locale/weightwc.h
* misc/reboot.c, nis/nis_table.c, nptl_db/thread_dbP.h
* nscd/connections.c, resolv/res_send.c, soft-fp/fmadf4.c
* soft-fp/fmasf4.c, soft-fp/fmatf4.c, stdio-common/vfscanf.c
* sysdeps/ieee754/dbl-64/e_lgamma_r.c
* sysdeps/ieee754/dbl-64/k_rem_pio2.c
* sysdeps/ieee754/flt-32/e_lgammaf_r.c
* sysdeps/ieee754/flt-32/k_rem_pio2f.c
* sysdeps/ieee754/ldbl-128/k_tanl.c
* sysdeps/ieee754/ldbl-128ibm/k_tanl.c
* sysdeps/ieee754/ldbl-96/e_lgammal_r.c
* sysdeps/ieee754/ldbl-96/k_tanl.c, sysdeps/nptl/futex-internal.h:
Include libc-diag.h instead of libc-internal.h.
* elf/dl-load.c, elf/dl-reloc.c, locale/programs/locarchive.c
* nptl/nptl-init.c, string/strcspn.c, string/strspn.c
* malloc/malloc.c, sysdeps/i386/nptl/tls.h
* sysdeps/nacl/dl-map-segments.h, sysdeps/x86_64/atomic-machine.h
* sysdeps/unix/sysv/linux/spawni.c
* sysdeps/x86_64/nptl/tls.h:
Include libc-pointer-arith.h instead of libc-internal.h.
* elf/get-dynamic-info.h, sysdeps/nacl/dl-map-segments.h
* sysdeps/x86_64/atomic-machine.h:
Add multiple include guard.
* elf/dl-load.c (_dl_map_object_from_fd): Add additional parameter
for original name of the DSO. Add it to the name list of the DSO
if it is actually given.
(_dl_map_object): Keep track of whether an audit module rewrote
the file name. If yes, pass the original name to
_dl_map_object_from_fd in a new parameter, otherwise NULL. When
debugging is enabled, log the change of the file name.
* sysdeps/mach/hur/dl-sysdep.c: Adjust commented-out call to
_dl_map_object_from_fd.
* elf/Makefile: Build and run tst-audit11 and tst-audit12.
* elf/tst-audit11.c: New file
* elf/tst-auditmod11.c: New file.
* elf/tst-audit11mod1.c: New file.
* elf/tst-audit11mod2.c: New file.
* elf/tst-audit11mod2.map: New file.
* elf/tst-audit12.c: New file
* elf/tst-auditmod12.c: New file.
* elf/tst-audit12mod1.c: New file.
* elf/tst-audit12mod2.c: New file.
* elf/tst-audit12mod2.map: New file.
* elf/tst-audit12mod3.c: New file.
Cleanup _dl_map_object_from_fd to make it clear exactly
what we're doing with the mappings i.e. extending the the
start of the map down to a page boundary, extending the
end of the map up to a page boundary, and offset itself
also to page boundary. The result is much easier to read
as expected from the ALIGN_* cleanups.
The ability to recursively call dlopen is useful for malloc
implementations that wish to load other dynamic modules that
implement reentrant/AS-safe functions to use in their own
implementation.
Given that a user malloc implementation may be called by an
ongoing dlopen to allocate memory the user malloc
implementation interrupts dlopen and if it calls dlopen again
that's a reentrant call.
This patch fixes the issues with the ld.so.cache mapping
and the _r_debug assertion which prevent this from working
as expected.
See:
https://sourceware.org/ml/libc-alpha/2014-12/msg00446.html
This hook can be used to perform additional compatibility checks
between shared libraries by inspecting custom program header
information.
* elf/dl-machine-reject-phdr.h: New file.
* elf/dl-load.c: #include that.
(open_verify): Call elf_machine_reject_phdr_p and ignore the file
if that returned true.
During a refactoring pass several repeated blocks of code in dl-load.c
were turned into a call to a local function named local_strdup. There
is no need for local_strdup, and the routines should instead call
__strdup. This change does just that. We call the internal symbol
__strdup because calling strdup is unsafe. The user might be
using a standard that doesn't include strdup and may have defined this
symbol in their application. During a static link we might reference
the user defined symbol and crash if it doesn't implement a standards
conforming strdup. The resulting code is simpler to understand, and
makes it easier to debug.
No regressions on x86_64.
2014-10-28 Carlos O'Donell <carlos@redhat.com>
* dl-load.c (local_strdup): Remove.
(expand_dynamic_string_token): Use __strdup.
(decompose_rpath): Likewise.
(_dl_map_object): Likewise.
Continuing the removal of the obsolete INTDEF / INTVARDEF / INTUSE
mechanism, this patch replaces its use for __libc_enable_secure with
the use of rtld_hidden_data_def and rtld_hidden_proto.
Tested for x86_64 that installed stripped shared libraries are
unchanged by the patch.
[BZ #14132]
* elf/dl-sysdep.c (__libc_enable_secure): Use rtld_hidden_data_def
instead of INTVARDEF.
(_dl_sysdep_start): Do not use INTUSE with __libc_enable_secure.
* sysdeps/mach/hurd/dl-sysdep.c (__libc_enable_secure): Use
rtld_hidden_data_def instead of INTVARDEF.
(_dl_sysdep_start): Do not use INTUSE with __libc_enable_secure.
* elf/dl-deps.c (expand_dst): Likewise.
* elf/dl-load.c (_dl_dst_count): Likewise.
(_dl_dst_substitute): Likewise.
(decompose_rpath): Likewise.
(_dl_init_paths): Likewise.
(open_path): Likewise.
(_dl_map_object): Likewise.
* elf/rtld.c (dl_main): Likewise.
(process_dl_audit): Likewise.
(process_envvars): Likewise.
* include/unistd.h [IS_IN_rtld] (__libc_enable_secure_internal):
Remove declaration.
(__libc_enable_secure): Use rtld_hidden_proto.
An application that erroneously tries to repeatedly dlopen("a.out", ...)
may hit assertion failure:
Inconsistency detected by ld.so: dl-tls.c: 474: _dl_allocate_tls_init:
Assertion `listp != ((void *)0)' failed!
dlopen() actually fails with "./a.out: cannot dynamically load executable",
but it does so after incrementing dl_tls_max_dtv_idx.
Once we run out of TLS_SLOTINFO_SURPLUS (62), we exit with above assertion
failure.
2014-03-24 Paul Pluzhnikov <ppluzhnikov@google.com>
[BZ #16634]
* elf/dl-load.c (open_verify): Add mode parameter.
Error early when ET_EXEC and mode does not have __RTLD_OPENEXEC.
(open_path): Change from boolean 'secure' to complete flag 'mode'
(_dl_map_object): Adjust.
* elf/Makefile (tests): Add tst-dlopen-aout.
* elf/tst-dlopen-aout.c: New test.
Fixes to address issues from BZ #15022 resolution, as follows:
* TLS updates to csu/libc-tls.c -- we now have a proper main map, so
there's no longer a need to create a separate fake one to keep TLS
structures,
* random updates to elf/dl-close.c -- LM_ID_BASE is now a valid name
space ID for static executables as well, so assert that we don't
unload the main map. Similarly dl_nns isn't supposed to be 0 for
static executables anymore,
* actual BZ #16046 fix to elf/dl-iteratephdr.c -- the dl_iterate_phdr
special function for static executables isn't needed anymore, provided
that l_phdr and l_phnum members of the main map have been properly
initialized (done in _dl_non_dynamic_init in elf/dl-support.c now),
* ld.so.cache loader update to elf/dl-load.c --
GL(dl_ns)[LM_ID_BASE]._ns_loaded is now always initialized in static
executables so can become the fallback loader map to check for
DF_1_NODEFLIB, provided that the l_flags_1 member of the main map has
been properly initialized (done in elf/dl-support.c now); this also
ensures previous semantics elsewhere in elf/dl-load.c,
* matching updates to elf/dl-support.c -- to complement the two fixes
above.
This change creates a link map in static executables to serve as the
global search list for dlopen. It fixes a problem with the inability
to access the global symbol object and a crash on an attempt to map a
DSO into the global scope. Some code that has become dead after the
addition of this link map is removed too and test cases are provided.
Resolves: #15465
The program name may be unavailable if the user application tampers
with argc and argv[]. Some parts of the dynamic linker caters for
this while others don't, so this patch consolidates the check and
fallback into a single macro and updates all users.
This hook is useful for any arch-specific functionality that
should be done on loaded objects. For the tile architecture,
the hook is already provided (though we switch to using the new
macro name with this commit) and implements a simulator notifier
so that the simulator can load Elf symbols to match the object
and generate better error messages for PC's.
Also, remove a spurious definition of DL_UNMAP in dl-runtime.c
It may sometimes be desirable to make the dynamic linker only pick up
libraries from the library path and rpath and not look at the
ld.so.cache that ldconfig generates. An example of such a use case is
the glibc testsuite where the dynamic linker must not be influenced by
any external paths or caches.
This change adds a new option --inhibit-ldcache that when used, tells
the dynamic linker to not use ld.so.cache even if it is available.
If we should use further fields in the e_ident array in the ELF header
of files we want zero to mean the default. Enforce zero for now so
that non-optional features indicated by nonzero values are not go
unnoticed when using an old dynamic linker.
from definition.
* sysdeps/x86_64/dl-machine.h (elf_machine_rela): Don't define
label if it is not used.
* elf/dl-profile.c (_dl_start_profile): Define real-type variant
of gmon_hist_hdr and gmon_hdr structures and use them.
* elf/dl-load.c (open_verify): Add temporary variable to avoid
warning.
* nscd/nscd_helper.c (get_mapping): Avoid casts to avoid warnings.
* sunrpc/clnt_raw.c (clntraw_private_s): Use union in definition
to avoid cast.
* inet/rexec.c (rexec_af): Make sa2 a union to avoid warnings.
* inet/rcmd.c (rcmd_af): Make from a union of the various needed types
to avoid warnings.
(iruserok_af): Use ss_family instead of casts.
* gmon/gmon.c (write_hist): Define real-type variant of
gmon_hist_hdr structure and use it.
(write_gmon): Likewise for gmon_hdr.
* sysdeps/unix/sysv/linux/readv.c: Avoid declaration of replacement
function if we are not going to define it.
* sysdeps/unix/sysv/linux/writev.c: Likewise.
* inet/inet6_option.c (optin_alloc): Add temporary variable to
avoid warning.
* libio/strfile.h (struct _IO_streambuf): Use correct type and
name of VTable element.
* libio/iovsprintf.c: Avoid casts to avoid warnings.
* libio/iovsscanf.c: Likewise.
* libio/vasprintf.c: Likewise.
* libio/vsnprintf.c: Likewise.
* stdio-common/isoc99_vsscanf.c: Likewise.
* stdlib/strfmon_l.c: Likewise.
* debug/vasprintf_chk.c: Likewise.
* debug/vsnprintf_chk.c: Likewise.
* debug/vsprintf_chk.c: Likewise.
* elf/dl-load.c (_dl_map_object_from_fd): Only call audit hooks
if we are not loading a new audit library.
* elf/dl-reloc (_dl_relocate_object): Third parameter is now a bitmask.
Only use profiling trampoline for auditing if we are not relocating
an audit library.
* elf/dl-open.c (dl_open_worker): Adjust _dl_relocate_object call.
* elf/rtld.c: Likewise.
* sysdeps/generic/ldsodefs.h: Adjust _dl_relocate_object prototype.
defined, allow additional data to be added using the optional
MORE_ELF_HEADER_DATA macro.
* sysdeps/unix/sysv/linux/ldsodefs.h (VALID_ELF_HEADER,
VALID_ELF_OSABI, VALID_ELF_ABIVERSION, MORE_ELF_HEADER_DATA): Define.
2007-10-28 Ulrich Drepper <drepper@redhat.com>
[BZ #5222]
* elf/dl-load.c (_dl_rtld_di_serinfo): Correct handling of short
path elements in counting mode.
failed.
* intl/finddomain.c (_nl_find_domain): Free normalized_codeset
on failure.
* elf/dl-load.c (decompose_rpath): Free copy if result couldn't be
allocated.
2007-08-03 Jakub Jelinek <jakub@redhat.com>
to fill in holes
(rtld_global_ro): Likewise.
2007-06-18 Jakub Jelinek <jakub@redhat.com>
* elf/dl-addr.c (_dl_addr): Skip PT_LOAD checking if l_contiguous.
Move PT_LOAD checking to...
(_dl_addr_inside_object): ... here, new function.
* elf/dl-sym.c (do_sym): If not l_contiguous,
call _dl_addr_inside_object.
* elf/dl-iteratephdr.c (__dl_iterate_phdr): Likewise.
* dlfcn/dlinfo.c (dlinfo_doit): Likewise.
* elf/dl-open.c (dl_open_worker): Likewise.
(_dl_addr_inside_object): New function if IS_IN_rtld.
* elf/dl-load.c (_dl_map_object_from_fd): Set l_contiguous if no
holes are present or are PROT_NONE protected.
* include/link.h (struct link_map): Add l_contiguous field.
* sysdeps/generic/ldsodefs.h (_dl_addr_inside_object): New prototype.
rather than r->r_brk.
2006-11-08 Jakub Jelinek <jakub@redhat.com>
* elf/dl-load.c (decompose_rpath): Return bool rather than void.
If l->l_name is on inhibit_rpath list, set sps->dirs to -1 and
return false, otherwise return true.
(cache_rpath): Return decompose_rpath return value.
2006-11-07 Jakub Jelinek <jakub@redhat.com>
* include/libc-symbols.h (declare_symbol): Rename to...
(declare_symbol_alias): ... this. Add ORIGINAL argument, imply
strong_alias (ORIGINAL, SYMBOL) in asm to make sure it preceedes
.size directive.
* sysdeps/gnu/errlist-compat.awk: Adjust for declare_symbol_alias
changes.
* sysdeps/gnu/siglist.c: Likewise.
argument.
(_dl_lookup_symbol_x): Adjust caller.
* sysdeps/generic/ldsodefs.h (struct link_namespaces): Remove
_ns_global_scope.
* elf/rtld.c (dl_main): Don't initialize _ns_global_scope.
* elf/dl-libc.c: Revert l_scope name changes.
* elf/dl-load.c: Likewise.
* elf/dl-object.c: Likewise.
* elf/rtld.c: Likewise.
* elf/dl-close.c (_dl_close): Likewise.
* elf/dl-open.c (dl_open_worker): Likewise. If not SINGLE_THREAD_P,
always use __rtld_mrlock_{change,done}. Always free old scope list
here if not l_scope_mem.
* elf/dl-runtime.c (_dl_fixup, _dl_profile_fixup): Revert l_scope name
change. Never free scope list here. Just __rtld_mrlock_lock before
the lookup and __rtld_mrlock_unlock it after the lookup.
* elf/dl-sym.c: Likewise.
* include/link.h (struct r_scoperec): Remove.
(struct link_map): Replace l_scoperec with l_scope, l_scoperec_mem
with l_scope_mem and l_scoperec_lock with l_scope_lock.
Implement reference counting of scope records.
* elf/dl-close.c (_dl_close): Remove all scopes from removed objects
from the list in objects which remain. Always allocate new scope
record.
* elf/dl-open.c (dl_open_worker): When growing array for scopes,
don't resize, allocate a new one.
* elf/dl-runtime.c: Update reference counters before using a scope
array.
* elf/dl-sym.c: Likewise.
* elf/dl-libc.c: Adjust for l_scope name change.
* elf/dl-load.c: Likewise.
* elf/dl-object.c: Likewise.
* elf/rtld.c: Likewise.
* include/link.h: Inlcude <rtld-lowlevel.h>. Define struct
r_scoperec. Replace r_scope with pointer to r_scoperec structure.
Add l_scoperec_lock.
* sysdeps/generic/ldsodefs.h: Include <rtld-lowlevel.h>.
* sysdeps/generic/rtld-lowlevel.h: New file.
* include/atomic.h: Rename atomic_and to atomic_and_val and
atomic_or to atomic_or_val. Define new macros atomic_and and
atomic_or which do not return values.
* sysdeps/x86_64/bits/atomic.h: Define atomic_and and atomic_or.
Various cleanups.
* sysdeps/i386/i486/bits/atomic.h: Likewise.
was allocated here. [Coverity CID 219]
* posix/getconf.c (print_all): Free confstr data after printing.
[Coverity CID 218]
* sysdeps/posix/getaddrinfo.c (gaih_inet): Free canon string if
list allocation fails. [Coverity CID 215]
* nss/nsswitch.c (__nss_configure_lookup): Fix loop end condition.
[Coverity CID 213]
* argp/argp-help.c (hol_entry_cmp): Don't call canon_doc_option if
string is NULL. [Coverity CID 212]
* argp/Makefile: Add rules to build and run bug-argp1.
* argp/bug-argp1.c: New file.
* io/ftw.c (ftw_dir): Use __rawmemchr instead of strchr to find
end of string.
* stdlib/canonicalize.c (__realpath): Likewise.
* locale/programs/ld-time.c (time_finish): Don't dereference NULL
pointer. [Coverity CID 206]
* elf/dl-dst.h (DL_DST_REQUIRED): Be prepared for missing link map
in statically linked code.
* elf/dl-load.c (_dl_dst_substitute): When replacing ORIGIN in
statically built code, be prepared to have no link map.
[Coverity CID 205]
* argp/argp-help.c (fill_in_uparams): Handle STATE==NULL in
dgettext calls. [Coverity CID 204]
* argp/argp-help.c (struct uparams): Remove valid member. Change
the one user.
(uparam_names): Reduce size. Avoid relative relocations.
Moved to read-only segment.
(fill_in_uparams): Update for new layout.
* sysdeps/unix/sysv/linux/ifaddrs.c (getifaddrs): Parameter can be
assumed to always be != NULL. [Coverity CID 202]
* argp/argp-help.c (hol_entry_help): Remove some dead code
[Coverity CID 200].
* nis/nss_nis/nis-service.c (_nss_nis_getservbyport_r): Optimize
away a few more unconditional yperr2nss calls.
(_nss_nis_getservbyname_r): Likewise.
2006-03-13 Jakub Jelinek <jakub@redhat.com>
[BZ #2451]
* elf/dl-load.c (open_verify): Add free_name argument, if true, free
name before calling lose.
(open_path): Adjust caller.
(_dl_map_object): Adjust callers. Free name_copy before calling
_dl_signal_error.
* elf/Makefile: Add rules to build and run tst-leaks1.
* elf/tst-leaks1.c: New test.
* elf/dl-load.c (MAP_COPY): When undefined, define to
MAP_PRIVATE|MAP_DENYWRITE instead of just MAP_PRIVATE.
(_dl_map_object_from_fd): Don't use MAP_DENYWRITE explicitly.
2005-09-20 Roland McGrath <roland@redhat.com>
[BZ #1346]
* elf/dl-load.c (_dl_map_object_from_fd) [HAVE_Z_RELRO]: Do relro
magic on __stack_prot only if [SHARED]. Skip mprotect if __stack_prot
lies outside the page-rounded-down relro region.
(INTERNAL_SYSCALL_ERROR_P): Fix typo in last change.
* sunrpc/xdr.c (xdr_u_int): Use `long' for L and cast where needed.
* elf/dl-load.c: Revert last change.
[(NEED_DL_SYSINFO || NEED_DL_SYSINFO_DSO) && SHARED]: Scan
GLRO(dl_sysinfo_map) for PT_NOTE giving Linux kernel version,
we can skip the uname call if it's there.
* sysdeps/generic/dl-sysdep.c (_dl_sysdep_start): Don't use
DL_SYSDEP_OSCHECK here.
* elf/rtld.c (dl_main) [DL_SYSDEP_OSCHECK]: Do it here instead.
* sysdeps/generic/ldsodefs.h (struct rtld_global_ro):
Add _dl_sysinfo_map.
* elf/rtld.c (dl_main): Don't call _dl_init_paths early in the
rtld_is_main case. Call it unconditionally later.
Move GLRO(dl_sysinfo_dso) handling earlier, before _dl_init_paths call.
Initialize GLRO(dl_sysinfo_map).
* elf/dl-load.c (open_path): Bail out if _dl_init_paths wasn't called.
* sysdeps/generic/dl-sysdep.c (_DL_FIRST_EXTRA): New macro.
(_dl_important_hwcaps)
[(NEED_DL_SYSINFO || NEED_DL_SYSINFO_DSO) && SHARED]: Scan
GLRO(dl_sysinfo_map) for PT_NOTE giving synthetic hwcap names
and bit values.
* elf/ldconfig.c (_DL_FIRST_EXTRA): New macro.
(hwcap_extra): New static variable.
(is_hwcap_platform): Check hwcap_extra for a matching name.
Remove tls special case.
(path_hwcap): Likewise.
(parse_conf): Parse "hwcap" directive to define synthetic hwcap bits
and their names, stored in hwcap_extra.
(main) [USE_TLS]: Initialize final synthetic hwcap bit as "tls".
* sysdeps/generic/ldsodefs.h (struct rtld_global_ro): Use uint64_t for
_dl_hwcap and _dl_hwcap_mask.
* sysdeps/generic/dl-sysdep.c (_dl_sysdep_start): Cast a_val for
AT_HWCAP to unsigned long int.
* elf/dl-support.c (_dl_aux_init): Likewise.
(_dl_hwcap): Update defn.
* elf/cache.c (print_entry): Pad hwcap value with 0s in diagnostic.
* elf/ldconfig.c (search_dir): Likewise.
Change type of l_idx to int.
* elf/dl-close.c: Basically rewrite. Do not use l_opencount to
determine whether a DSO has to be unloaded. Instead compute this
in this function.
* elf/dl-deps.c: No need to manipulate l_opencount anymore.
* elf/dl-lookup.c: Likewise.
* elf/rtld.c: Likewise
* elf/dl-open.c: Likewise. Use l_init_called to determine whether
object was just loaded.
* elf/dl-fini.c: Bump l_direct_opencount instead of l_opencount.
* elf/dl-load.c (_dl_map_object_from_fd): Do not recognize DSO which
is about to be unloaded as a match.
(_dl_map_object): Likewise.
* elf/do-lookup.h (do_lookup_x): Do not look into DSO which is about
to be unloaded.
* elf/circleload1.c: Don't use l_opencount anymore.
* elf/neededtest.c: Likewise.
* elf/neededtest2.c: Likewise.
* elf/neededtest3.c: Likewise.
* elf/neededtest4.c: Likewise.
* elf/unload.c: Likewise.
* elf/unload2.c: Likewise.
* elf/loadtest.c: Likewise.
* elf/rtld.c: Preloading errors are now never fatal.
2005-03-08 Jakub Jelinek <jakub@redhat.com>
* elf/Makefile: Add rules to build and run unload5 test.
* elf/unload5.c: New file.
2005-03-08 Jakub Jelinek <jakub@redhat.com>
* elf/Makefile: Add rules to build and run unload4 test.
* elf/unload4.c: New file.
* elf/unload4mod1.c: New file.
* elf/unload4mod2.c: New file.
* elf/unload4mod3.c: New file.
* elf/unload4mod4.c: New file.
slotinfo array.
(__libc_setup_tls_): Initializer length of DTV based on array length.
* elf/dl-load.c: Revert last change.
* sysdeps/generic/dl-tls.c: Revert last change.
