I used these shell commands:
../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")
and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 7061 files FOO.
I then removed trailing white space from math/tgmath.h,
support/tst-support-open-dev-null-range.c, and
sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following
obscure pre-commit check failure diagnostics from Savannah. I don't
know why I run into these diagnostics whereas others evidently do not.
remote: *** 912-#endif
remote: *** 913:
remote: *** 914-
remote: *** error: lines with trailing whitespace found
...
remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
It can be used to speed up the libgcc unwinder, and the internal
_dl_find_dso_for_object function (which is used for caller
identification in dlopen and related functions, and in dladdr).
_dl_find_object is in the internal namespace due to bug 28503.
If libgcc switches to _dl_find_object, this namespace issue will
be fixed. It is located in libc for two reasons: it is necessary
to forward the call to the static libc after static dlopen, and
there is a link ordering issue with -static-libgcc and libgcc_eh.a
because libc.so is not a linker script that includes ld.so in the
glibc build tree (so that GCC's internal -lc after libgcc_eh.a does
not pick up ld.so).
It is necessary to do the i386 customization in the
sysdeps/x86/bits/dl_find_object.h header shared with x86-64 because
otherwise, multilib installations are broken.
The implementation uses software transactional memory, as suggested
by Torvald Riegel. Two copies of the supporting data structures are
used, also achieving full async-signal-safety.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
The rtld-audit interfaces introduces a slowdown due to enabling
profiling instrumentation (as if LD_AUDIT implied LD_PROFILE).
However, instrumenting is only necessary if one of audit libraries
provides PLT callbacks (la_pltenter or la_pltexit symbols). Otherwise,
the slowdown can be avoided.
The following patch adjusts the logic that enables profiling to iterate
over all audit modules and check if any of those provides a PLT hook.
To keep la_symbind to work even without PLT callbacks, _dl_fixup now
calls the audit callback if the modules implements it.
Co-authored-by: Alexander Monakov <amonakov@ispras.ru>
Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
This second patch contains the actual implementation of a new sorting algorithm
for shared objects in the dynamic loader, which solves the slow behavior that
the current "old" algorithm falls into when the DSO set contains circular
dependencies.
The new algorithm implemented here is simply depth-first search (DFS) to obtain
the Reverse-Post Order (RPO) sequence, a topological sort. A new l_visited:1
bitfield is added to struct link_map to more elegantly facilitate such a search.
The DFS algorithm is applied to the input maps[nmap-1] backwards towards
maps[0]. This has the effect of a more "shallow" recursion depth in general
since the input is in BFS. Also, when combined with the natural order of
processing l_initfini[] at each node, this creates a resulting output sorting
closer to the intuitive "left-to-right" order in most cases.
Another notable implementation adjustment related to this _dl_sort_maps change
is the removing of two char arrays 'used' and 'done' in _dl_close_worker to
represent two per-map attributes. This has been changed to simply use two new
bit-fields l_map_used:1, l_map_done:1 added to struct link_map. This also allows
discarding the clunky 'used' array sorting that _dl_sort_maps had to sometimes
do along the way.
Tunable support for switching between different sorting algorithms at runtime is
also added. A new tunable 'glibc.rtld.dynamic_sort' with current valid values 1
(old algorithm) and 2 (new DFS algorithm) has been added. At time of commit
of this patch, the default setting is 1 (old algorithm).
Signed-off-by: Chung-Lin Tang <cltang@codesourcery.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
We can't relocate entries in dynamic section if it is readonly:
1. Add a l_ld_readonly field to struct link_map to indicate if dynamic
section is readonly and set it based on p_flags of PT_DYNAMIC segment.
2. Replace DL_RO_DYN_SECTION with dl_relocate_ld to decide if dynamic
section should be relocated.
3. Remove DL_RO_DYN_TEMP_CNT.
4. Don't use a static dynamic section to make readonly dynamic section
in vDSO writable.
5. Remove the temp argument from elf_get_dynamic_info.
This fixes BZ #28340.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Glibc does not provide an interface for debugger to access libraries
loaded in multiple namespaces via dlmopen.
The current rtld-debugger interface is described in the file:
elf/rtld-debugger-interface.txt
under the "Standard debugger interface" heading. This interface only
provides access to the first link-map (LM_ID_BASE).
1. Bump r_version to 2 when multiple namespaces are used. This triggers
the GDB bug:
https://sourceware.org/bugzilla/show_bug.cgi?id=28236
2. Add struct r_debug_extended to extend struct r_debug into a linked-list,
where each element correlates to an unique namespace.
3. Initialize the r_debug_extended structure. Bump r_version to 2 for
the new namespace and add the new namespace to the namespace linked list.
4. Add _dl_debug_update to return the address of struct r_debug' of a
namespace.
5. Add a hidden symbol, _r_debug_extended, for struct r_debug_extended.
6. Provide the symbol, _r_debug, with size of struct r_debug, as an alias
of _r_debug_extended, for programs which reference _r_debug.
This fixes BZ #15971.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
I used these shell commands:
../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")
and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 6694 files FOO.
I then removed trailing white space from benchtests/bench-pthread-locks.c
and iconvdata/tst-iconv-big5-hkscs-to-2ucs4.c, to work around this
diagnostic from Savannah:
remote: *** pre-commit check failed ...
remote: *** error: lines with trailing whitespace found
remote: error: hook declined to update refs/heads/master
They have been renamed from env_path_list and rtld_search_dirs to
avoid linknamespace issues.
This change will allow future use these variables in diagnostics.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Commit a2e8aa0d9e ("Block signals during
the initial part of dlopen") was deemed necessary because of
read-modify-write operations like the one in add_dependency in
elf/dl-lookup.c. In the old code, we check for any kind of NODELETE
status and bail out:
/* Redo the NODELETE check, as when dl_load_lock wasn't held
yet this could have changed. */
if (map->l_nodelete != link_map_nodelete_inactive)
goto out;
And then set pending status (during relocation):
if (flags & DL_LOOKUP_FOR_RELOCATE)
map->l_nodelete = link_map_nodelete_pending;
else
map->l_nodelete = link_map_nodelete_active;
If a signal arrives during relocation and the signal handler, through
lazy binding, adds a global scope dependency on the same map, it will
set map->l_nodelete to link_map_nodelete_active. This will be
overwritten with link_map_nodelete_pending by the dlopen relocation
code.
To avoid such problems in relation to the l_nodelete member, this
commit introduces two flags for active NODELETE status (irrevocable)
and pending NODELETE status (revocable until activate_nodelete is
invoked). As a result, NODELETE processing in dlopen does not
introduce further reasons why lazy binding from signal handlers
is unsafe during dlopen, and a subsequent commit can remove signal
blocking from dlopen.
This does not address pre-existing issues (unrelated to the NODELETE
changes) which make lazy binding in a signal handler during dlopen
unsafe, such as the use of malloc in both cases.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
This introduces a “pending NODELETE” state in the link map, which is
flipped to the persistent NODELETE state late in dlopen, via
activate_nodelete. During initial relocation, symbol binding
records pending NODELETE state only. dlclose ignores pending NODELETE
state. Taken together, this results that a partially completed dlopen
is rolled back completely because new NODELETE mappings are unloaded.
Tested on x86_64-linux-gnu and i386-linux-gnu.
Change-Id: Ib2a3d86af6f92d75baca65431d74783ee0dbc292
l_audit ends up as an internal array with _rtld_global, and GCC 10
warns about this.
This commit does not change the layout of _rtld_global, so it is
suitable for backporting. Future changes could allocate more of the
audit state dynamically and remove it from always-allocated data
structures, to optimize the common case of inactive auditing.
Change-Id: Ic911100730f9124d4ea977ead8e13cee64b84d45
There is a data-dependency between the fields of struct l_reloc_result
and the field used as the initialization guard. Users of the guard
expect writes to the structure to be observable when they also observe
the guard initialized. The solution for this problem is to use an acquire
and release load and store to ensure previous writes to the structure are
observable if the guard is initialized.
The previous implementation used DL_FIXUP_VALUE_ADDR (l_reloc_result->addr)
as the initialization guard, making it impossible for some architectures
to load and store it atomically, i.e. hppa and ia64, due to its larger size.
This commit adds an unsigned int to l_reloc_result to be used as the new
initialization guard of the struct, making it possible to load and store
it atomically in all architectures. The fix ensures that the values
observed in l_reloc_result are consistent and do not lead to crashes.
The algorithm is documented in the code in elf/dl-runtime.c
(_dl_profile_fixup). Not all data races have been eliminated.
Tested with build-many-glibcs and on powerpc, powerpc64, and powerpc64le.
[BZ #23690]
* elf/dl-runtime.c (_dl_profile_fixup): Guarantee memory
modification order when accessing reloc_result->addr.
* include/link.h (reloc_result): Add field init.
* nptl/Makefile (tests): Add tst-audit-threads.
(modules-names): Add tst-audit-threads-mod1 and
tst-audit-threads-mod2.
Add rules to build tst-audit-threads.
* nptl/tst-audit-threads-mod1.c: New file.
* nptl/tst-audit-threads-mod2.c: Likewise.
* nptl/tst-audit-threads.c: Likewise.
* nptl/tst-audit-threads.h: Likewise.
Signed-off-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
To support Intel Control-flow Enforcement Technology (CET) run-time
control:
1. An architecture specific field in the writable ld.so namespace is
needed to indicate if CET features are enabled at run-time.
2. An architecture specific field in struct link_map is needed if
CET features are enabled in an ELF module.
This patch adds dl-procruntime.c to the writable ld.so namespace and
link_map.h to struct link_map.
Tested with build-many-glibcs.py.
* elf/dl-support.c: Include <dl-procruntime.c>.
* include/link.h: Include <link_map.h>.
* sysdeps/generic/dl-procruntime.c: New file.
* sysdeps/generic/link_map.h: Likewise.
* sysdeps/generic/ldsodefs.h: Include <dl-procruntime.c> in
the writable ld.so namespace.
__dl_iterate_phdr is hidden and should be accessed directly within
libc.so and libc.a without using GOT nor PLT.
[BZ #18822]
* elf/dl-iteratephdr.c (hidden_proto (__dl_iterate_phdr)): Moved
to ...
* include/link.h (hidden_proto (__dl_iterate_phdr)): Here.
This adds a test to ensure that the problems fixed in the last several
patches do not recur. Each directory checks the headers that it
installs for two properties: first, each header must be compilable in
isolation, as both C and C++, under a representative combination of
language and library conformance levels; second, there is a blacklist
of identifiers that may not appear in any installed header, currently
consisting of the legacy BSD typedefs. (There is an exemption for the
headers that define those typedefs, and for the RPC headers. It may be
necessary to make this more sophisticated if we add more stuff to the
blacklist in the future.)
In order for this test to work correctly, every wrapper header
that actually defines something must guard those definitions with
#ifndef _ISOMAC. This is the existing mechanism used by the conform/
tests to tell wrapper headers not to define anything that the public
header wouldn't, and not to use anything from libc-symbols.h. conform/
only cares for headers that we need to check for standards conformance,
whereas this test applies to *every* header. (Headers in include/ that
are either installed directly, or are internal-use-only and do *not*
correspond to any installed header, are not affected.)
* scripts/check-installed-headers.sh: New script.
* Rules: In each directory that defines header files to be installed,
run check-installed-headers.sh on them as a special test.
* Makefile: Likewise for the headers installed at top level.
* include/aliases.h, include/alloca.h, include/argz.h
* include/arpa/nameser.h, include/arpa/nameser_compat.h
* include/elf.h, include/envz.h, include/err.h
* include/execinfo.h, include/fpu_control.h, include/getopt.h
* include/gshadow.h, include/ifaddrs.h, include/libintl.h
* include/link.h, include/malloc.h, include/mcheck.h
* include/mntent.h, include/netinet/ether.h
* include/nss.h, include/obstack.h, include/printf.h
* include/pty.h, include/resolv.h, include/rpc/auth.h
* include/rpc/auth_des.h, include/rpc/auth_unix.h
* include/rpc/clnt.h, include/rpc/des_crypt.h
* include/rpc/key_prot.h, include/rpc/netdb.h
* include/rpc/pmap_clnt.h, include/rpc/pmap_prot.h
* include/rpc/pmap_rmt.h, include/rpc/rpc.h
* include/rpc/rpc_msg.h, include/rpc/svc.h
* include/rpc/svc_auth.h, include/rpc/xdr.h
* include/rpcsvc/nis_callback.h, include/rpcsvc/nislib.h
* include/rpcsvc/yp.h, include/rpcsvc/ypclnt.h
* include/rpcsvc/ypupd.h, include/shadow.h
* include/stdio_ext.h, include/sys/epoll.h
* include/sys/file.h, include/sys/gmon.h, include/sys/ioctl.h
* include/sys/prctl.h, include/sys/profil.h
* include/sys/statfs.h, include/sys/sysctl.h
* include/sys/sysinfo.h, include/ttyent.h, include/utmp.h
* sysdeps/arm/nacl/include/bits/setjmp.h
* sysdeps/mips/include/sys/asm.h
* sysdeps/unix/sysv/linux/include/sys/sysinfo.h
* sysdeps/unix/sysv/linux/include/sys/timex.h
* sysdeps/x86/fpu/include/bits/fenv.h:
Add #ifndef _ISOMAC guard around internal declarations.
Add multiple-inclusion guard if not already present.
It was noted in
<https://sourceware.org/ml/libc-alpha/2012-09/msg00305.html> that the
bits/*.h naming scheme should only be used for installed headers.
This patch renames bits/linkmap.h to plain linkmap.h to follow that
convention.
Tested for x86_64 (testsuite, and that installed stripped shared
libraries are unchanged by the patch).
[BZ #14912]
* bits/linkmap.h: Move to ...
* sysdeps/generic/linkmap.h: ...here.
* sysdeps/aarch64/bits/linkmap.h: Move to ...
* sysdeps/aarch64/linkmap.h: ...here.
* sysdeps/arm/bits/linkmap.h: Move to ...
* sysdeps/arm/linkmap.h: ...here.
* sysdeps/hppa/bits/linkmap.h: Move to ...
* sysdeps/hppa/linkmap.h: ...here.
* sysdeps/ia64/bits/linkmap.h: Move to ...
* sysdeps/ia64/linkmap.h: ...here.
* sysdeps/mips/bits/linkmap.h: Move to ...
* sysdeps/mips/linkmap.h: ...here.
* sysdeps/s390/bits/linkmap.h: Move to ...
* sysdeps/s390/linkmap.h: ...here.
* sysdeps/sh/bits/linkmap.h: Move to ...
* sysdeps/sh/linkmap.h: ...here.
* sysdeps/x86/bits/linkmap.h: Move to ...
* sysdeps/x86/linkmap.h: ...here.
* include/link.h: Include <linkmap.h> instead of <bits/linkmap.h>.
When an TLS destructor is registered, we set the DF_1_NODELETE flag to
signal that the object should not be destroyed. We then clear the
DF_1_NODELETE flag when all destructors are called, which is wrong -
the flag could have been set by other means too.
This patch replaces this use of the flag by using l_tls_dtor_count
directly to determine whether it is safe to unload the object. This
change has the added advantage of eliminating the lock taking when
calling the destructors, which could result in a deadlock. The patch
also fixes the test case tst-tls-atexit - it was making an invalid
dlclose call, which would just return an error silently.
I have also added a detailed note on concurrency which also aims to
justify why I chose the semantics I chose for accesses to
l_tls_dtor_count. Thanks to Torvald for his help in getting me
started on this and (literally) teaching my how to approach the
problem.
Change verified on x86_64; the test suite does not show any
regressions due to the patch.
ChangeLog:
[BZ #18657]
* elf/dl-close.c (_dl_close_worker): Don't unload DSO if there
are pending TLS destructor calls.
* include/link.h (struct link_map): Add concurrency note for
L_TLS_DTOR_COUNT.
* stdlib/cxa_thread_atexit_impl.c (__cxa_thread_atexit_impl):
Don't touch the link map flag. Atomically increment
l_tls_dtor_count.
(__call_tls_dtors): Atomically decrement l_tls_dtor_count.
Avoid taking the load lock and don't touch the link map flag.
* stdlib/tst-tls-atexit-nodelete.c: New test case.
* stdlib/Makefile (tests): Use it.
* stdlib/tst-tls-atexit.c (do_test): dlopen
tst-tls-atexit-lib.so again before dlclose. Add conditionals
to allow tst-tls-atexit-nodelete test case to use it.
This feature is specifically for the C++ compiler to offload calling
thread_local object destructors on thread program exit, to glibc.
This is to overcome the possible complication of destructors of
thread_local objects getting called after the DSO in which they're
defined is unloaded by the dynamic linker. The DSO is marked as
'unloadable' if it has a constructed thread_local object and marked as
'unloadable' again when all the constructed thread_local objects
defined in it are destroyed.
[BZ #13579] Do not free l_initfini and allow it to be reused
on subsequent dl_open calls for the same library. This fixes
the invalid memory access in do_lookup_x when the previously
free'd l_initfini was accessed through l_searchlist when a
library had been opened for the second time.
On some architectures the update of the l_used field in the lookup
functions races with setting the other bits in the bitfield. Simply
avoid this and optimize use of l_used in general.
* elf/dl-close.c (_dl_close): Check for it.
* elf/dl-reloc.c (CHECK_STATIC_TLS): Likewise.
(_dl_allocate_static_tls): Likewise.
* elf/dl-tls.c (_dl_allocate_tls_init): Likewise.
(__tls_get_addr): Protect from race conditions in setting l_tls_offset
to it.
* elf/tst-tls16.c: New file.
* elf/tst-tlsmod16a.c: New file.
* elf/tst-tlsmod16b.c: New file.
* elf/Makefile: Add rules to build and run tst-tls16.
void * pointers instead of struct link_map **.
(_dl_scope_free): Change argument type to void *.
* include/link.h (struct link_map): Change type of l_reldeps
to struct link_map_reldeps, move l_reldepsact into that
struct too.
* elf/dl-deps.c: Include atomic.h.
(_dl_map_object_deps): Only change l->l_initfini when it is
fully populated, use _dl_scope_free for freeing it. Optimize
removal of libs from reldeps by using l_reserved flag, when
some removal is needed, allocate a new list instead of
reallocating and free the old with _dl_scope_free. Adjust
for l_reldeps and l_reldepsact changes.
* elf/dl-lookup.c (add_dependency): Likewise. Reorganize to allow
searching in l_initfini and l_reldeps without holding dl_load_lock.
* elf/dl-fini.c (_dl_sort_fini): Adjust for l_reldeps and
l_reldepsact changes.
* elf/dl-close.c (_dl_close_worker): Likewise.
* elf/dl-open.c (_dl_scope_free): Change argument type to void *.
* elf/dl-runtime.c (_dl_fixup, _dl_profile_fixup): Or in
DL_LOOKUP_GSCOPE_LOCK into flags after THREAD_GSCOPE_SET_FLAG ().
* elf/dl-sym.c (do_sym): Likewise.
* include/link.h (struct link_map): Add l_serial field.
* elf/dl-object.c (_dl_new_object): Initialize l_serial.
* elf/dl-lookup.c (add_dependency): Add flags argument.
Remember map->l_serial, if DL_LOOKUP_GSCOPE_LOCK is among
flags, use THREAD_GSCOPE_RESET_FLAG before and
THREAD_GSCOPE_SET_FLAG after
__rtld_lock_lock_recursive (GL(dl_load_lock)) to avoid deadlock.
Don't dereference map until it has been found on some list.
If map->l_serial changed, return -1.
2007-06-13 Jakub Jelinek <jakub@redhat.com>
* include/link.h: Don't include rtld-lowlevel.h.
(struct link_map): Remove l_scope_lock.
* sysdeps/generic/ldsodefs.h: Don't include rtld-lowlevel.h.
(_dl_scope_free_list): New field (variable) in _rtld_global.
(DL_LOOKUP_SCOPE_LOCK): Remove.
(_dl_scope_free): New prototype.
* elf/dl-runtime.c (_dl_fixup): Don't use __rtld_mrlock_*lock.
Don't pass DL_LOOKUP_SCOPE_LOCK to _dl_lookup_symbol_x.
(_dl_profile_fixup): Likewise.
* elf/dl-sym.c (do_sym): Likewise. Use wrapped _dl_lookup_symbol_x
whenever !RTLD_SINGLE_THREAD_P, use THREAD_GSCOPE_SET_FLAG and
THREAD_GSCOPE_RESET_FLAG around it.
* elf/dl-close.c (_dl_close_worker): Don't use
__rtld_mrlock_{change,done}. Call _dl_scope_free on the old
scope. Make sure THREAD_GSCOPE_WAIT () happens if any old
scopes were queued or if l_scope_mem has been abandoned.
* elf/dl-open.c (_dl_scope_free): New function.
(dl_open_worker): Use it. Don't use __rtld_mrlock_{change,done}.
* elf/dl-support.c (_dl_scope_free_list): New variable.
* elf/dl-lookup.c (add_dependency): Remove flags argument.
Remove DL_LOOKUP_SCOPE_LOCK handling.
(_dl_lookup_symbol_x): Adjust caller. Remove DL_LOOKUP_SCOPE_LOCK
handling.
* elf/dl-object.c (_dl_new_object): Don't use
__rtld_mrlock_initialize.
2007-06-19 Ulrich Drepper <drepper@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.
* sysdeps/unix/sysv/linux/Makefile [subdir=posix] (tests): Add
tst-getcpu.
* include/link.h: Move l_version and l_nversion members around to
fill gaps.
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.
