* 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.
prelink runs ld.so with the environment variable LD_TRACE_PRELINKING
set to dump the relocation type class from _dl_debug_bindings. prelink
has the following relocation type classes:
#define RTYPE_CLASS_VALID 8
#define RTYPE_CLASS_PLT (8|1)
#define RTYPE_CLASS_COPY (8|2)
#define RTYPE_CLASS_TLS (8|4)
where ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA has a conflict with
RTYPE_CLASS_TLS.
Since prelink only uses ELF_RTYPE_CLASS_PLT and ELF_RTYPE_CLASS_COPY
bits, we should clear the other bits when the DL_DEBUG_PRELINK bit is
set.
[BZ #19178]
* elf/dl-lookup.c (RTYPE_CLASS_VALID): New.
(RTYPE_CLASS_PLT): Likewise.
(RTYPE_CLASS_COPY): Likewise.
(RTYPE_CLASS_TLS): Likewise.
(_dl_debug_bindings): Use RTYPE_CLASS_TLS and RTYPE_CLASS_VALID
to set relocation type class for DL_DEBUG_PRELINK. Keep only
ELF_RTYPE_CLASS_PLT and ELF_RTYPE_CLASS_COPY bits for
DL_DEBUG_PRELINK.
In this case, extend_alloca is used to work around the lack of
deallocation on scope exit. A VLA is automatically deallocated in this
way, so it is the more fitting approach.
To implement this, it is necessary to eliminate the goto. In addition,
this change eliminates the trivially-true assert; the assert is always
skipped if nloaded > 0.
* elf/dl-fini.c (_dl_fini): Rewrite to use variable-length array
instead of extend_alloca. Change control flow to avoid a goto.
Remove assert which is trivially always true.
Added AT_PLATFORM to _dl_aux_init () function to keep it in sync with
_dl_sysdep_start ().
* elf/dl-support.c (_dl_aux_init): Added AT_PLATFORM to the case
statement.
This mostly automatically-generated patch converts 113 function
definitions in glibc from old-style K&R to prototype-style. Following
my other recent such patches, this one deals with the case of function
definitions in files that either contain assertions or where grep
suggested they might contain assertions - and thus where it isn't
possible to use a simple object code comparison as a sanity check on
the correctness of the patch, because line numbers are changed.
A few such automatically-generated changes needed to be supplemented
by manual changes for the result to compile. openat64 had a prototype
declaration with "..." but an old-style definition in
sysdeps/unix/sysv/linux/dl-openat64.c, and "..." needed adding to the
generated prototype in the definition (I've filed
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68024> for diagnosing
such cases in GCC; the old state was undefined behavior not requiring
a diagnostic, but one seems a good idea). In addition, as Florian has
noted regparm attribute mismatches between declaration and definition
are only diagnosed for prototype definitions, and five functions
needed internal_function added to their definitions (in the case of
__pthread_mutex_cond_lock, via the macro definition of
__pthread_mutex_lock) to compile on i386.
After this patch is in, remaining old-style definitions are probably
most readily fixed manually before we can turn on
-Wold-style-definition for all builds.
Tested for x86_64 and x86 (testsuite).
* crypt/md5-crypt.c (__md5_crypt_r): Convert to prototype-style
function definition.
* crypt/sha256-crypt.c (__sha256_crypt_r): Likewise.
* crypt/sha512-crypt.c (__sha512_crypt_r): Likewise.
* debug/backtracesyms.c (__backtrace_symbols): Likewise.
* elf/dl-minimal.c (_itoa): Likewise.
* hurd/hurdmalloc.c (malloc): Likewise.
(free): Likewise.
(realloc): Likewise.
* inet/inet6_option.c (inet6_option_space): Likewise.
(inet6_option_init): Likewise.
(inet6_option_append): Likewise.
(inet6_option_alloc): Likewise.
(inet6_option_next): Likewise.
(inet6_option_find): Likewise.
* io/ftw.c (FTW_NAME): Likewise.
(NFTW_NAME): Likewise.
(NFTW_NEW_NAME): Likewise.
(NFTW_OLD_NAME): Likewise.
* libio/iofwide.c (_IO_fwide): Likewise.
* libio/strops.c (_IO_str_init_static_internal): Likewise.
(_IO_str_init_static): Likewise.
(_IO_str_init_readonly): Likewise.
(_IO_str_overflow): Likewise.
(_IO_str_underflow): Likewise.
(_IO_str_count): Likewise.
(_IO_str_seekoff): Likewise.
(_IO_str_pbackfail): Likewise.
(_IO_str_finish): Likewise.
* libio/wstrops.c (_IO_wstr_init_static): Likewise.
(_IO_wstr_overflow): Likewise.
(_IO_wstr_underflow): Likewise.
(_IO_wstr_count): Likewise.
(_IO_wstr_seekoff): Likewise.
(_IO_wstr_pbackfail): Likewise.
(_IO_wstr_finish): Likewise.
* locale/programs/localedef.c (normalize_codeset): Likewise.
* locale/programs/locarchive.c (add_locale_to_archive): Likewise.
(add_locales_to_archive): Likewise.
(delete_locales_from_archive): Likewise.
* malloc/malloc.c (__libc_mallinfo): Likewise.
* math/gen-auto-libm-tests.c (init_fp_formats): Likewise.
* misc/tsearch.c (__tfind): Likewise.
* nptl/pthread_attr_destroy.c (__pthread_attr_destroy): Likewise.
* nptl/pthread_attr_getdetachstate.c
(__pthread_attr_getdetachstate): Likewise.
* nptl/pthread_attr_getguardsize.c (pthread_attr_getguardsize):
Likewise.
* nptl/pthread_attr_getinheritsched.c
(__pthread_attr_getinheritsched): Likewise.
* nptl/pthread_attr_getschedparam.c
(__pthread_attr_getschedparam): Likewise.
* nptl/pthread_attr_getschedpolicy.c
(__pthread_attr_getschedpolicy): Likewise.
* nptl/pthread_attr_getscope.c (__pthread_attr_getscope):
Likewise.
* nptl/pthread_attr_getstack.c (__pthread_attr_getstack):
Likewise.
* nptl/pthread_attr_getstackaddr.c (__pthread_attr_getstackaddr):
Likewise.
* nptl/pthread_attr_getstacksize.c (__pthread_attr_getstacksize):
Likewise.
* nptl/pthread_attr_init.c (__pthread_attr_init_2_1): Likewise.
(__pthread_attr_init_2_0): Likewise.
* nptl/pthread_attr_setdetachstate.c
(__pthread_attr_setdetachstate): Likewise.
* nptl/pthread_attr_setguardsize.c (pthread_attr_setguardsize):
Likewise.
* nptl/pthread_attr_setinheritsched.c
(__pthread_attr_setinheritsched): Likewise.
* nptl/pthread_attr_setschedparam.c
(__pthread_attr_setschedparam): Likewise.
* nptl/pthread_attr_setschedpolicy.c
(__pthread_attr_setschedpolicy): Likewise.
* nptl/pthread_attr_setscope.c (__pthread_attr_setscope):
Likewise.
* nptl/pthread_attr_setstack.c (__pthread_attr_setstack):
Likewise.
* nptl/pthread_attr_setstackaddr.c (__pthread_attr_setstackaddr):
Likewise.
* nptl/pthread_attr_setstacksize.c (__pthread_attr_setstacksize):
Likewise.
* nptl/pthread_condattr_setclock.c (pthread_condattr_setclock):
Likewise.
* nptl/pthread_create.c (__find_in_stack_list): Likewise.
* nptl/pthread_getattr_np.c (pthread_getattr_np): Likewise.
* nptl/pthread_mutex_cond_lock.c (__pthread_mutex_lock): Define to
use internal_function.
* nptl/pthread_mutex_init.c (__pthread_mutex_init): Convert to
prototype-style function definition.
* nptl/pthread_mutex_lock.c (__pthread_mutex_lock): Likewise.
(__pthread_mutex_cond_lock_adjust): Likewise. Use
internal_function.
* nptl/pthread_mutex_timedlock.c (pthread_mutex_timedlock):
Convert to prototype-style function definition.
* nptl/pthread_mutex_trylock.c (__pthread_mutex_trylock):
Likewise.
* nptl/pthread_mutex_unlock.c (__pthread_mutex_unlock_usercnt):
Likewise.
(__pthread_mutex_unlock): Likewise.
* nptl_db/td_ta_clear_event.c (td_ta_clear_event): Likewise.
* nptl_db/td_ta_set_event.c (td_ta_set_event): Likewise.
* nptl_db/td_thr_clear_event.c (td_thr_clear_event): Likewise.
* nptl_db/td_thr_event_enable.c (td_thr_event_enable): Likewise.
* nptl_db/td_thr_set_event.c (td_thr_set_event): Likewise.
* nss/makedb.c (process_input): Likewise.
* posix/fnmatch.c (__strchrnul): Likewise.
(__wcschrnul): Likewise.
(fnmatch): Likewise.
* posix/fnmatch_loop.c (FCT): Likewise.
* posix/glob.c (globfree): Likewise.
(__glob_pattern_type): Likewise.
(__glob_pattern_p): Likewise.
* posix/regcomp.c (re_compile_pattern): Likewise.
(re_set_syntax): Likewise.
(re_compile_fastmap): Likewise.
(regcomp): Likewise.
(regerror): Likewise.
(regfree): Likewise.
* posix/regexec.c (regexec): Likewise.
(re_match): Likewise.
(re_search): Likewise.
(re_match_2): Likewise.
(re_search_2): Likewise.
(re_search_stub): Likewise. Use internal_function
(re_copy_regs): Likewise.
(re_set_registers): Convert to prototype-style function
definition.
(prune_impossible_nodes): Likewise. Use internal_function.
* resolv/inet_net_pton.c (inet_net_pton): Convert to
prototype-style function definition.
(inet_net_pton_ipv4): Likewise.
* stdlib/strtod_l.c (____STRTOF_INTERNAL): Likewise.
* sysdeps/pthread/aio_cancel.c (aio_cancel): Likewise.
* sysdeps/pthread/aio_suspend.c (aio_suspend): Likewise.
* sysdeps/pthread/timer_delete.c (timer_delete): Likewise.
* sysdeps/unix/sysv/linux/dl-openat64.c (openat64): Likewise.
Make variadic.
* time/strptime_l.c (localtime_r): Convert to prototype-style
function definition.
* wcsmbs/mbsnrtowcs.c (__mbsnrtowcs): Likewise.
* wcsmbs/mbsrtowcs_l.c (__mbsrtowcs_l): Likewise.
* wcsmbs/wcsnrtombs.c (__wcsnrtombs): Likewise.
* wcsmbs/wcsrtombs.c (__wcsrtombs): Likewise.
There is a configure test for assembler support for the
gnu_unique_object symbol type. This support was added in binutils
2.20, so is present in all versions supported for building glibc.
Thus, I think the configure test can be removed; this patch does so.
Now, there is a caveat that the gas NEWS entry refers to this as a
feature for GNU/Linux targets. But the condition is use of
ELFOSABI_GNU or ELFOSABI_NONE. ELFOSABI_GNU covers Hurd as well as
GNU/Linux (as was the case with the older ELFOSABI_LINUX name), and
ELFOSABI_NONE means this is effectively OS-independent. Furthermore,
I think a correct binutils port for any glibc target ought to support
this feature for use with glibc; glibc supports this as an
OS-independent feature (the configure test is only about glibc
testcases).
Tested for x86_64 (testsuite, and that installed shared libraries are
unchanged by the patch).
* configure.ac (libc_cv_asm_unique_object): Remove configure test.
* configure: Regenerated.
* config.h.in (HAVE_ASM_UNIQUE_OBJECT): Remove #undef.
* elf/tst-unique1.c (do_test) [HAVE_ASM_UNIQUE_OBJECT]: Make code
unconditional.
* elf/tst-unique1mod1.c [HAVE_ASM_UNIQUE_OBJECT]: Likewise.
* elf/tst-unique1mod2.c [HAVE_ASM_UNIQUE_OBJECT]: Likewise.
* elf/tst-unique2.c (do_test) [HAVE_ASM_UNIQUE_OBJECT]: Likewise.
(do_test) [!HAVE_ASM_UNIQUE_OBJECT]: Remove conditional code.
* elf/tst-unique2mod1.c [HAVE_ASM_UNIQUE_OBJECT]: Make code
unconditional.
* elf/tst-unique2mod2.c [HAVE_ASM_UNIQUE_OBJECT]: Likewise.
Honoring the LD_POINTER_GUARD environment variable in AT_SECURE mode
has security implications. This commit enables pointer guard
unconditionally, and the environment variable is now ignored.
[BZ #18928]
* sysdeps/generic/ldsodefs.h (struct rtld_global_ro): Remove
_dl_pointer_guard member.
* elf/rtld.c (_rtld_global_ro): Remove _dl_pointer_guard
initializer.
(security_init): Always set up pointer guard.
(process_envvars): Do not process LD_POINTER_GUARD.
Fix a regression introduced with commit 0d23a5c1 [Static dlopen
correction fallout fixes] that caused the default library search path to
be ignored for modules loaded with dlopen from static executables.
[BZ #17250]
* elf/dl-support.c (_dl_main_map): Don't initialize l_flags_1
member.
The test error messages incorrectly reference LIBC_SO
when they should reference the dlmopen'd library
tst-dlmopen1mod.so. Define TEST_SO and use it in
all the error messages.
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.
Fix the bind-now case when DT_REL and DT_JMPREL sections are separate
and there is a gap between them.
[BZ #14341]
* elf/dynamic-link.h (elf_machine_lazy_rel): Properly handle the
case when there is a gap between DT_REL and DT_JMPREL sections.
* sysdeps/x86_64/Makefile (tests): Add tst-split-dynreloc.
(LDFLAGS-tst-split-dynreloc): New.
(tst-split-dynreloc-ENV): Likewise.
* sysdeps/x86_64/tst-split-dynreloc.c: New file.
* sysdeps/x86_64/tst-split-dynreloc.lds: Likewise.
To remove -Wno-error=undef, we need to fix the remaining cases where
there are -Wundef warnings in the testsuite. One of those places is
in elf/tst-execstack.c.
tst-execstack.c tests USE_PTHREADS with #if. nptl/tst-execstack.c
defines USE_PTHREADS to 1 before including ../elf/tst-execstack.c,
while elf/tst-execstack.c, when compiled directly, leaves it
undefined.
This patch adds a setting of CPPFLAGS-tst-execstack.c to
elf/Makefile. An alternative approach would be to rename
tst-execstack.c to tst-execstack-main.c and have two different
tst-execstack.c files include it, each with an appropriate
USE_PTHREADS #define.
Tested for x86_64.
* elf/Makefile [$(have-z-execstack) = yes]
(CPPFLAGS-tst-execstack.c): New variable.
https://sourceware.org/bugzilla/show_bug.cgi?id=18778
If dlopen fails to load an object that has triggered loading libpthread it
causes ld.so to unload libpthread because its DF_1_NODELETE flags has been
forcefully cleared. The next call to __rtdl_unlock_lock_recursive will crash
since pthread_mutex_unlock no longer exists.
This patch moves l->l_flags_1 &= ~DF_1_NODELETE out of loop through all loaded
libraries and performs the action only on inconsistent one.
[BZ #18778]
* elf/Makefile (tests): Add Add tst-nodelete2.
(modules-names): Add tst-nodelete2mod.
(tst-nodelete2mod.so-no-z-defs): New.
($(objpfx)tst-nodelete2): Likewise.
($(objpfx)tst-nodelete2.out): Likewise.
(LDFLAGS-tst-nodelete2): Likewise.
* elf/dl-close.c (_dl_close_worker): Move DF_1_NODELETE clearing
out of loop through all loaded libraries.
* elf/tst-nodelete2.c: New file.
* elf/tst-nodelete2mod.c: Likewise.
These tests were skipped by the use-test-skeleton conversion done in
commit 29955b5d because they did not have an `int main (void)'
declaration. Instead their `main' functions were declared with arguments
(i.e. argc, argv) even though they didn't use them.
Remove these arguments and include the test skeleton in these tests.
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 symbol is defined in the ldso, and is used both there and libc.so.
There is no hidden symbol for it though which leads to relocations in
the ldso and the elf/check-localplt test failing. Add a hidden def for
rtld to fix all of that.
This function/file is only used by hppa & ia64, so no testing is needed
for other arches.
The DF_1_NODELETE flag is set too late when opening a DSO, due to
which, if a DSO is already open, subsequently opening it with
RTLD_NODELETE fails to set the DF_1_NODELETE flag. This patch fixes
this by setting the flag immediately after bumping the opencount.
Verified on x86_64.
[BZ #18676]
* elf/tst-nodelete-opened.c: New test case.
* elf/tst-nodelete-opened-lib.c: New test case module.
* elf/Makefile (tests, modules-names): Use them.
* elf/dl-open.c (dl_open_worker): Set DF_1_NODELETE flag
early.
These tests were skipped by the use-test-skeleton conversion done in
commit 29955b5d because they were reused in other tests via the #include
directive, and so deemed worth an inspection before they were modified.
This has now been done.
ChangeLog:
2015-07-09 Arjun Shankar <arjun.is@lostca.se>
* elf/tst-leaks1.c (main): Converted to ...
(do_test): ... this.
(TEST_FUNCTION): New macro.
Include test-skeleton.c.
* localedata/tst-langinfo.c (main): Converted to ...
(do_test): ... this.
(TEST_FUNCTION): New macro.
Include test-skeleton.c.
* math/test-fpucw.c (main): Converted to ...
(do_test): ... this.
(TEST_FUNCTION): New macro.
Include test-skeleton.c.
* math/test-tgmath.c (main): Converted to ...
(do_test): ... this.
(TEST_FUNCTION): New macro.
Include test-skeleton.c.
* math/test-tgmath2.c (main): Converted to ...
(do_test): ... this.
(TEST_FUNCTION): New macro.
Include test-skeleton.c.
* setjmp/tst-setjmp.c (main): Converted to ...
(do_test): ... this.
(TEST_FUNCTION): New macro.
Include test-skeleton.c.
* stdio-common/tst-sscanf.c (main): Converted to ...
(do_test): ... this.
(TEST_FUNCTION): New macro.
Include test-skeleton.c.
* sysdeps/x86_64/tst-audit6.c (main): Converted to ...
(do_test): ... this.
(TEST_FUNCTION): New macro.
Include test-skeleton.c.
This test was skipped by the use-test-skeleton conversion script
[29955b5d] because the definition of `main' did not begin according to
the GNU formatting style that the script assumed.
ChangeLog:
2015-07-09 Arjun Shankar <arjun.is@lostca.se>
* elf/tst-audit9.c (main): Converted to ...
(do_test): ... this.
(TEST_FUNCTION): New macro.
Include test-skeleton.c.
https://sourceware.org/bugzilla/show_bug.cgi?id=17833
I've a shared library that contains both undefined and unique symbols.
Then I try to call the following sequence of dlopen:
1. dlopen("./libfoo.so", RTLD_NOW)
2. dlopen("./libfoo.so", RTLD_LAZY | RTLD_GLOBAL)
First dlopen call terminates with error because of undefined symbols,
but STB_GNU_UNIQUE ones set DF_1_NODELETE flag and hence block library
in the memory.
The library goes into inconsistent state as several structures remain
uninitialized. For instance, relocations for GOT table were not performed.
By the time of second dlopen call this library looks like as it would be
fully initialized but this is not true: any call through incorrect GOT
table leads to segmentation fault. On some systems this inconsistency
triggers assertions in the dynamic linker.
This patch adds a parameter to _dl_close_worker to implement forced object
deletion in case of dlopen() failure:
1. Clears DF_1_NODELETE bit if forced, to allow library to be removed from
memory.
2. For each unique symbol that is defined in this object clears
appropriate entry in _ns_unique_sym_table.
[BZ #17833]
* elf/Makefile (tests): Add tst-nodelete.
(modules-names): Add tst-nodelete-uniquemod.
(tst-nodelete-uniquemod.so-no-z-defs): New.
(tst-nodelete-rtldmod.so-no-z-defs): Likewise.
(tst-nodelete-zmod.so-no-z-defs): Likewise.
($(objpfx)tst-nodelete): Likewise.
($(objpfx)tst-nodelete.out): Likewise.
(LDFLAGS-tst-nodelete): Likewise.
(LDFLAGS-tst-nodelete-zmod.so): Likewise.
* elf/dl-close.c (_dl_close_worker): Add a parameter to
implement forced object deletion.
(_dl_close): Pass false to _dl_close_worker.
* elf/dl-open.c (_dl_open): Pass true to _dl_close_worker.
* elf/tst-nodelete.cc: New file.
* elf/tst-nodeletelib.cc: Likewise.
* elf/tst-znodeletelib.cc: Likewise.
* include/dlfcn.h (_dl_close_worker): Add a new parameter.
This tag allows debugging of MIPS position independent executables
and provides access to shared library information.
* elf/elf.h (DT_MIPS_RLD_MAP_REL): New macro.
(DT_MIPS_NUM): Update.
* sysdeps/mips/dl-machine.h (ELF_MACHINE_DEBUG_SETUP): Handle
DT_MIPS_RLD_MAP_REL.
To support building glibc with GCC 6 configured with --enable-default-pie,
which generates PIE by default, we need to build programs as PIE. But
elf/tst-dlopen-aout must not be built as PIE since it tests dlopen on
ET_EXEC file and PIE is ET_DYN.
[BZ #17841]
* Makeconfig (no-pie-ldflag): New.
(+link): Set to $(+link-pie) if default to PIE.
(+link-tests): Set to $(+link-pie-tests) if default to PIE.
* config.make.in (build-pie-default): New.
* configure.ac (libc_cv_pie_default): New. Set to yes if -fPIE
is default. AC_SUBST.
* configure: Regenerated.
* elf/Makefile (LDFLAGS-tst-dlopen-aout): New.
We need to align TCB offset to the maximum alignment for TLS_TCB_AT_TP
targets, as _dl_allocate_tls_storage (in elf/dl-tls.c) does using
__libc_memalign and dl_tls_static_align.
[BZ #18383]
* csu/libc-tls.c (__libc_setup_tls) [TLS_TCB_AT_TP]: Align
TCB_OFFSET to MAX_ALIGN, not just TCBALIGN. Add comment.
* elf/Makefile (test-xfail-tst-tlsalign{,-static}): Remove
comment for i386/x86-64.
(test-xfail-tst-tlsalign-extern-static): Removed.
Many packages, including GCC, install Python files for GDB in library
diretory. ldconfig reads them and issue errors since they aren't ELF
files:
ldconfig: /usr/gcc-5.1.1/lib/libstdc++.so.6.0.21-gdb.py is not an ELF file - it has the wrong magic bytes at the start.
ldconfig: /usr/gcc-5.1.1/libx32/libstdc++.so.6.0.21-gdb.py is not an ELF file - it has the wrong magic bytes at the start.
ldconfig: /usr/gcc-5.1.1/lib64/libstdc++.so.6.0.21-gdb.py is not an ELF file - it has the wrong magic bytes at the start.
This patch silences ldconfig on GDB Python files by checking filenames
with -gdb.py suffix.
[BZ #18585]
* elf/readlib.c (is_gdb_python_file): New.
(process_file): Don't issue errors on filenames with -gdb.py
suffix.
Lazy TLSDESC initialization needs to be synchronized with concurrent TLS
accesses. The TLS descriptor contains a function pointer (entry) and an
argument that is accessed from the entry function. With lazy initialization
the first call to the entry function updates the entry and the argument to
their final value. A final entry function must make sure that it accesses an
initialized argument, this needs synchronization on systems with weak memory
ordering otherwise the writes of the first call can be observed out of order.
There are at least two issues with the current code:
tlsdesc.c (i386, x86_64, arm, aarch64) uses volatile memory accesses on the
write side (in the initial entry function) instead of C11 atomics.
And on systems with weak memory ordering (arm, aarch64) the read side
synchronization is missing from the final entry functions (dl-tlsdesc.S).
This patch only deals with aarch64.
* Write side:
Volatile accesses were replaced with C11 relaxed atomics, and a release
store was used for the initialization of entry so the read side can
synchronize with it.
* Read side:
TLS access generated by the compiler and an entry function code is roughly
ldr x1, [x0] // load the entry
blr x1 // call it
entryfunc:
ldr x0, [x0,#8] // load the arg
ret
Various alternatives were considered to force the ordering in the entry
function between the two loads:
(1) barrier
entryfunc:
dmb ishld
ldr x0, [x0,#8]
(2) address dependency (if the address of the second load depends on the
result of the first one the ordering is guaranteed):
entryfunc:
ldr x1,[x0]
and x1,x1,#8
orr x1,x1,#8
ldr x0,[x0,x1]
(3) load-acquire (ARMv8 instruction that is ordered before subsequent
loads and stores)
entryfunc:
ldar xzr,[x0]
ldr x0,[x0,#8]
Option (1) is the simplest but slowest (note: this runs at every TLS
access), options (2) and (3) do one extra load from [x0] (same address
loads are ordered so it happens-after the load on the call site),
option (2) clobbers x1 which is problematic because existing gcc does
not expect that, so approach (3) was chosen.
A new _dl_tlsdesc_return_lazy entry function was introduced for lazily
relocated static TLS, so non-lazy static TLS can avoid the synchronization
cost.
[BZ #18034]
* sysdeps/aarch64/dl-tlsdesc.h (_dl_tlsdesc_return_lazy): Declare.
* sysdeps/aarch64/dl-tlsdesc.S (_dl_tlsdesc_return_lazy): Define.
(_dl_tlsdesc_undefweak): Guarantee TLSDESC entry and argument load-load
ordering using ldar.
(_dl_tlsdesc_dynamic): Likewise.
(_dl_tlsdesc_return_lazy): Likewise.
* sysdeps/aarch64/tlsdesc.c (_dl_tlsdesc_resolve_rela_fixup): Use
relaxed atomics instead of volatile and synchronize with release store.
(_dl_tlsdesc_resolve_hold_fixup): Use relaxed atomics instead of
volatile.
* elf/tlsdeschtab.h (_dl_tlsdesc_resolve_early_return_p): Likewise.
Make runtime-linker.h available outside $(elf-objpfx) by moving
the file to $(common-objpfx) and the rules for it to Makerules.
Tested for x86_64 and x86 (testsuite, and that no compiled code
changed by the patch).
* Makeconfig (+interp): Remove unused variable.
* elf/Makefile ($(objpfx)interp.os): Define for [$(build-shared) = yes]
only. Depend on $(common-objpfx)runtime-linker.h instead of
$(elf-objpfx)runtime-linker.h.
($(elf-objpfx)runtime-linker.h): Rename to
$(common-objpfx)runtime-linker.h and move ...
* Makerules [$(build-shared) = yes]: ... here.
* elf/interp.c: Include <runtime-linker.h> instead of
<elf/runtime-linker.h>.
PLT relocations aren't required when -z now used. Linker on master with:
commit 25070364b0ce33eed46aa5d78ebebbec6accec7e
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Sat May 16 07:00:21 2015 -0700
Don't generate PLT relocations for now binding
There is no need for PLT relocations with -z now. We can use GOT
relocations, which take less space, instead and replace 16-byte .plt
entres with 8-byte .plt.got entries.
bfd/
* elf32-i386.c (elf_i386_check_relocs): Create .plt.got section
for now binding.
(elf_i386_allocate_dynrelocs): Use .plt.got section for now
binding.
* elf64-x86-64.c (elf_x86_64_check_relocs): Create .plt.got
section for now binding.
(elf_x86_64_allocate_dynrelocs): Use .plt.got section for now
binding.
won't generate PLT relocations with -z now. elf/tst-audit2.c expect
certain order of execution in ld.so. With PLT relocations, the GOTPLT
entry of calloc is update to calloc defined in tst-audit2:
(gdb) bt
skip_ifunc=<optimized out>, reloc_addr_arg=<optimized out>,
version=<optimized out>, sym=<optimized out>, map=<optimized out>)
at ../sysdeps/i386/dl-machine.h:329
out>,
nrelative=<optimized out>, relsize=<optimized out>,
reladdr=<optimized out>, map=<optimized out>) at do-rel.h:137
reloc_mode=reloc_mode@entry=0,
consider_profiling=1, consider_profiling@entry=0) at dl-reloc.c:258
user_entry=0xffffcf1c, auxv=0xffffd0a8) at rtld.c:2133
start_argptr=start_argptr@entry=0xffffcfb0,
dl_main=dl_main@entry=0xf7fda6f0 <dl_main>) at
../elf/dl-sysdep.c:249
from /export/build/gnu/glibc-32bit/build-i686-linux/elf/ld.so
(gdb)
and then calloc is called:
(gdb) c
Continuing.
Breakpoint 4, calloc (n=n@entry=20, m=4) at tst-audit2.c:18
18 {
(gdb) bt
reloc_mode=reloc_mode@entry=0, consider_profiling=1,
consider_profiling@entry=0) at dl-reloc.c:272
user_entry=0xffffcf1c, auxv=0xffffd0a8) at rtld.c:2133
start_argptr=start_argptr@entry=0xffffcfb0,
dl_main=dl_main@entry=0xf7fda6f0 <dl_main>) at
../elf/dl-sysdep.c:249
from /export/build/gnu/glibc-32bit/build-i686-linux/elf/ld.so
(gdb)
With GOT relocation, calloc in ld.so is called first:
(gdb) bt
consider_profiling=1) at dl-reloc.c:272
user_entry=0xffffcf0c, auxv=0xffffd098) at rtld.c:2074
start_argptr=start_argptr@entry=0xffffcfa0,
dl_main=dl_main@entry=0xf7fda6c0 <dl_main>) at
../elf/dl-sysdep.c:249
from /export/build/gnu/glibc-32bit-test/build-i686-linux/elf/ld.so
(gdb)
and then the GOT entry of calloc is updated:
(gdb) bt
skip_ifunc=<optimized out>, reloc_addr_arg=<optimized out>,
version=<optimized out>, sym=<optimized out>, map=<optimized out>)
at ../sysdeps/i386/dl-machine.h:329
out>,
nrelative=<optimized out>, relsize=<optimized out>,
reladdr=<optimized out>, map=<optimized out>) at do-rel.h:137
reloc_mode=reloc_mode@entry=0,
consider_profiling=1, consider_profiling@entry=0) at dl-reloc.c:258
user_entry=0xffffcf0c, auxv=0xffffd098) at rtld.c:2133
start_argptr=start_argptr@entry=0xffffcfa0,
dl_main=dl_main@entry=0xf7fda6c0 <dl_main>) at
../elf/dl-sysdep.c:249
from /export/build/gnu/glibc-32bit-test/build-i686-linux/elf/ld.so
(gdb)
After that, since calloc isn't called from ld.so nor any other modules,
magic in tst-audit2 isn't updated. Both orders are correct. This patch
makes sure that calloc in tst-audit2.c is called at least once from ld.so.
[BZ #18422]
* Makefile ($(objpfx)tst-audit2): Depend on $(libdl).
($(objpfx)tst-audit2.out): Also depend on
$(objpfx)tst-auditmod9b.so.
* elf/tst-audit2.c: Include <dlfcn.h>.
(calloc_called): New.
(calloc): Allow to be called more than once.
(do_test): dllopen/dlclose $ORIGIN/tst-auditmod9b.so.
A shared object doesn't need PLT if there are no PLT relocations. It
shouldn't be an error if DT_PLTRELSZ is missing.
[BZ #18410]
* elf/dl-reloc.c (_dl_relocate_object): Don't issue an error
for missing DT_PLTRELSZ.
Any use of SHF_EXCLUDE in code that tries to check it against sh_flags
will trigger undefined behaviour because it is defined as a 31 bit shift
against an signed integer. Fix by explicitly using an unsigned int.
