The glibc 2.34 release really should have added a GLIBC_2.34
symbol to the dynamic loader. With it, we could move functions such
as dlopen or pthread_key_create that work on process-global state
into the dynamic loader (once we have fixed a longstanding issue
with static linking). Without the GLIBC_2.34 symbol, yet another
new symbol version would be needed because old glibc will fail to
load binaries due to the missing symbol version in ld.so that newly
linked programs will require.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
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>
It consolidates the code required to call la_preinit audit
callback.
Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
It consolidates the code required to call la_symbind{32,64} audit
callback.
Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
They are no longer needed after everything has been moved into
libc. The _dl_vsym test has to be removed because the symbol
cannot be used outside libc anymore.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Consolidate all hooks structures into a single one. There are
no static dlopen ABI concerns because glibc 2.34 already comes
with substantial ABI-incompatible changes in this area. (Static
dlopen requires the exact same dynamic glibc version that was used
for static linking.)
The new approach uses a pointer to the hooks structure into
_rtld_global_ro and initalizes it in __rtld_static_init. This avoids
a back-and-forth with various callback functions.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This change makes it easier to set a breakpoint on these calls.
This also addresses the issue that including <ldsodefs.h> without
<unistd.h> does not result usable _dl_*printf macros because of the
use of the STD*_FILENO macros there.
(The private symbol for _dl_fatal_printf will go away again
once the exception handling implementation is unified between
libc and ld.so.)
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This function is defined in libc.so, and the dynamic loader calls
right after relocation has been finished, before any ELF constructors
or the preinit function is invoked. It is also used in the static
build for initializing parts of the static libc.
To locate __libc_early_init, a direct symbol lookup function is used,
_dl_lookup_direct. It does not search the entire symbol scope and
consults merely a single link map. This function could also be used
to implement lookups in the vDSO (as an optimization).
A per-namespace variable (libc_map) is added for locating libc.so,
to avoid repeated traversals of the search scope. It is similar to
GL(dl_initfirst). An alternative would have been to thread a context
argument from _dl_open down to _dl_map_object_from_fd (where libc.so
is identified). This could have avoided the global variable, but
the change would be larger as a result. It would not have been
possible to use this to replace GL(dl_initfirst) because that global
variable is used to pass the function pointer past the stack switch
from dl_main to the main program. Replacing that requires adding
a new argument to _dl_init, which in turn needs changes to the
architecture-specific libc.so startup code written in assembler.
__libc_early_init should not be used to replace _dl_var_init (as
it exists today on some architectures). Instead, _dl_lookup_direct
should be used to look up a new variable symbol in libc.so, and
that should then be initialized from the dynamic loader, immediately
after the object has been loaded in _dl_map_object_from_fd (before
relocation is run). This way, more IFUNC resolvers which depend on
these variables will work.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Exporting functions and relying on symbol interposition from libc.so
makes the choice of implementation dependent on DT_NEEDED order, which
is not what some compiler drivers expect.
This commit replaces one magic mechanism (symbol interposition) with
another one (preprocessor-/compiler-based redirection). This makes
the hand-over from the minimal malloc to the full malloc more
explicit.
Removing the ABI symbols is backwards-compatible because libc.so is
always in scope, and the dynamic loader will find the malloc-related
symbols there since commit f0b2132b35
("ld.so: Support moving versioned symbols between sonames
[BZ #24741]").
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
This commit adds a new _dl_open_hook entry for dlvsym and implements the
function using the existing dl_lookup_symbol_x function supplied by the
dynamic loader.
A new hook variable, _dl_open_hook2, is introduced, which should make
this change suitable for backporting: For old statically linked
binaries, __libc_dlvsym will always return NULL.
This commit separates allocating and raising exceptions. This
simplifies catching and re-raising them because it is no longer
necessary to make a temporary, on-stack copy of the exception message.
Since _dl_out_of_memory is static in elf/dl-error-skeleton.c:
static const char _dl_out_of_memory[] = "out of memory";
remove _dl_out_of_memory from elf/Versions.
* elf/Versions (ld): Remove _dl_out_of_memory.
The TUNABLE_SET_VALUE and family of macros (and my later attempt to
add a TUNABLE_GET) never quite went together very well because the
overall interface was not clearly defined. This patch is an attempt
to do just that.
This patch consolidates the API to two simple sets of macros,
TUNABLE_GET* and TUNABLE_SET*. If TUNABLE_NAMESPACE is defined,
TUNABLE_GET takes just the tunable name, type and a (optionally NULL)
callback function to get the value of the tunable. The callback
function, if non-NULL, is called if the tunable was externally set
(i.e. via GLIBC_TUNABLES or any future mechanism). For example:
val = TUNABLE_GET (check, int32_t, check_callback)
returns the value of the glibc.malloc.check tunable (assuming
TUNABLE_NAMESPACE is set to malloc) as an int32_t into VAL after
calling check_callback.
Likewise, TUNABLE_SET can be used to set the value of the tunable,
although this is currently possible only in the dynamic linker before
it relocates itself. For example:
TUNABLE_SET (check, int32_t, 2)
will set glibc.malloc.check to 2. Of course, this is not possible
since we set (or read) glibc.malloc.check long after it is relocated.
To access or set a tunable outside of TUNABLE_NAMESPACE, use the
TUNABLE_GET_FULL and TUNABLE_SET_FULL macros, which have the following
prototype:
TUNABLE_GET_FULL (glibc, tune, hwcap_mask, uint64_t, NULL)
TUNABLE_SET_FULL (glibc, tune, hwcap_mask, uint64_t, 0xffff)
In future the tunable list may get split into mutable and immutable
tunables where mutable tunables can be modified by the library and
userspace after relocation as well and TUNABLE_SET will be more useful
than it currently is. However whenever we actually do that split, we
will have to ensure that the mutable tunables are protected with
locks.
* elf/Versions (__tunable_set_val): Rename to __tunable_get_val.
* elf/dl-tunables.c: Likewise.
(do_tunable_update_val): New function.
(__tunable_set_val): New function.
(__tunable_get_val): Call CB only if the tunable was externally
initialized.
(tunables_strtoul): Replace strval with initialized.
* elf/dl-tunables.h (strval): Replace with a bool initialized.
(TUNABLE_ENUM_NAME, TUNABLE_ENUM_NAME1): Adjust names to
prevent collision.
(__tunable_set_val): New function.
(TUNABLE_GET, TUNABLE_GET_FULL): New macros.
(TUNABLE_SET, TUNABLE_SET_FULL): Likewise.
(TUNABLE_SET_VAL): Remove.
(TUNABLE_SET_VAL_WITH_CALLBACK): Likewise.
* README.tunables: Document the new macros.
* malloc/arena.c (ptmalloc_init): Adjust.
The tunables framework allows us to uniformly manage and expose global
variables inside glibc as switches to users. tunables/README has
instructions for glibc developers to add new tunables.
Tunables support can be enabled by passing the --enable-tunables
configure flag to the configure script. This patch only adds a
framework and does not pose any limitations on how tunable values are
read from the user. It also adds environment variables used in malloc
behaviour tweaking to the tunables framework as a PoC of the
compatibility interface.
* manual/install.texi: Add --enable-tunables option.
* INSTALL: Regenerate.
* README.tunables: New file.
* Makeconfig (CPPFLAGS): Define TOP_NAMESPACE.
(before-compile): Generate dl-tunable-list.h early.
* config.h.in: Add HAVE_TUNABLES.
* config.make.in: Add have-tunables.
* configure.ac: Add --enable-tunables option.
* configure: Regenerate.
* csu/init-first.c (__libc_init_first): Move
__libc_init_secure earlier...
* csu/init-first.c (LIBC_START_MAIN):... to here.
Include dl-tunables.h, libc-internal.h.
(LIBC_START_MAIN) [!SHARED]: Initialize tunables for static
binaries.
* elf/Makefile (dl-routines): Add dl-tunables.
* elf/Versions (ld): Add __tunable_set_val to GLIBC_PRIVATE
namespace.
* elf/dl-support (_dl_nondynamic_init): Unset MALLOC_CHECK_
only when !HAVE_TUNABLES.
* elf/rtld.c (process_envvars): Likewise.
* elf/dl-sysdep.c [HAVE_TUNABLES]: Include dl-tunables.h
(_dl_sysdep_start): Call __tunables_init.
* elf/dl-tunable-types.h: New file.
* elf/dl-tunables.c: New file.
* elf/dl-tunables.h: New file.
* elf/dl-tunables.list: New file.
* malloc/tst-malloc-usable-static.c: New test case.
* malloc/Makefile (tests-static): Add it.
* malloc/arena.c [HAVE_TUNABLES]: Include dl-tunables.h.
Define TUNABLE_NAMESPACE.
(DL_TUNABLE_CALLBACK (set_mallopt_check)): New function.
(DL_TUNABLE_CALLBACK_FNDECL): New macro. Use it to define
callback functions.
(ptmalloc_init): Set tunable values.
* scripts/gen-tunables.awk: New file.
* sysdeps/mach/hurd/dl-sysdep.c: Include dl-tunables.h.
(_dl_sysdep_start): Call __tunables_init.
Commit 7a5e3d9d63 (elf: Assume TLS is
initialized in _dl_map_object_from_fd) removed the last call of
_dl_tls_setup, but did not remove the function itself.
It is no longer needed since commit 6c444ad6e9
(elf: Do not use memalign for TCB/TLS blocks allocation [BZ #17730]).
Applications do not link against ld.so and will use the definition in
libc.so, so there is no ABI impact.
This change moves the main implementation of _dl_catch_error,
_dl_signal_error to libc.so, where TLS variables can be used
directly. This removes a writable function pointer from the
rtld_global variable.
For use during initial relocation, minimal implementations of these
functions are provided in ld.so. These are eventually interposed
by the libc.so implementations. This is implemented by compiling
elf/dl-error-skeleton.c twice, via elf/dl-error.c and
elf/dl-error-minimal.c.
As a side effect of this change, the static version of dl-error.c
no longer includes support for the
_dl_signal_cerror/_dl_receive_error mechanism because it is only
used in ld.so.
* elf/Makefile (tests): Add it.
($(objpfx)tst-tls-dlinfo): Depend on $(libdl).
($(objpfx)tst-tls-dlinfo.out): Depend on $(objpfx)tst-tlsmod2.so.
* dlfcn/dlfcn.h (RTLD_DI_PROFILENAME, RTLD_DI_PROFILEOUT): New enum
values, reserve unsupported requested names used on Solaris.
(RTLD_DI_TLS_MODID, RTLD_DI_TLS_DATA): New enum values.
(RTLD_DI_MAX): Likewise.
* dlfcn/dlinfo.c (dlinfo_doit): Handle RTLD_DI_TLS_MODID and
RTLD_DI_TLS_DATA.
* elf/dl-tls.c (_dl_tls_get_addr_soft): New function.
* sysdeps/generic/ldsodefs.h: Declare it.
* elf/Versions (ld: GLIBC_PRIVATE): Add it.
* elf/link.h (struct dl_phdr_info): New members dlpi_tls_modid,
dlpi_tls_data.
* elf/dl-iteratephdr.c (__dl_iterate_phdr): Fill them in.
* include/link.h: Don't copy contents from elf/link.h.
Instead, #include it while #define'ing around link_map.
* elf/dl-debug.c (_dl_debug_initialize): Add a cast.
Add bogus extern decl to verify link_map members.
* elf/loadtest.c (MAPS): New macro, cast _r_debug._r_map.
(OUT, main): Use it in place of _r_debug._r_map.
* elf/unload.c: Likewise.
* elf/unload2.c: Likewise.
* elf/neededtest.c (check_loaded_objects): Likewise.
* elf/neededtest2.c (check_loaded_objects): Likewise.
* elf/neededtest3.c (check_loaded_objects): Likewise.
* elf/neededtest4.c (check_loaded_objects): Likewise.
* elf/circleload1.c (check_loaded_objects): Likewise.
* elf/rtld.c: Define __pointer_chk_guard_local and if necessary
__pointer_chk_guard.
(_rtld_global_ro): Initialize _dl_pointer_guard.
(dl_main): Initialize __pointer_chk_guard_local and either
__pointer_chk_guard or TLS value if necessary.
(process_envvars): Recognize and handle LD_POINTER_GUARD.
* sysdeps/generic/ldsodefs.h (rtld_global_ro): Add _dl_pointer_guard.
* sysdeps/i386/__longjmp.S: Use PTR_DEMANGLE for PC if defined.
* sysdeps/x86_64/__longjmp.S: Likewise.
* sysdeps/i386/bsd-_setjmp.S: Use PTR_MANGLE for PC if defined.
* sysdeps/i386/bsd-_setjmp.S: Likewise.
* sysdeps/i386/setjmp.S: Likewise.
[IS_IN_rtld]: Avoid call to __sigjmp_save.
* sysdeps/i386/setjmp.S: Likewise.
* sysdeps/unix/sysv/linux/i386/sysdep.h: Define PTR_MANGLE and
PTR_DEMANGLE.
* sysdeps/unix/sysv/linux/x86_64/sysdep.h: Likewise.
* sysdeps/i386/elf/setjmp.S: Removed.
* sysdeps/i386/elf/bsd-setjmp.S: Removed.
* configure.in: Add --enable-stackguard-randomization option.
(ENABLE_STACKGUARD_RANDOMIZE): New define.
* config.h.in (ENABLE_STACKGUARD_RANDOMIZE): Add.
* sysdeps/unix/sysv/linux/dl-osinfo.h: Include stdint.h.
(_dl_setup_stack_chk_guard): New inline function.
* sysdeps/generic/dl-osinfo.h: Include stdint.h.
(_dl_setup_stack_chk_guard): New inline function.
* elf/rtld.c (__stack_chk_guard): New variable.
(dl_main): Remove all traces of TLS_INIT_TP_EXPENSIVE.
Set __stack_chk_guard to _dl_setup_stack_chk_guard (),
use THREAD_SET_STACK_GUARD if defined.
* elf/Versions (ld): Export __stack_chk_guard@@GLIBC_2.4.
* sysdeps/generic/libc-start.c (__stack_chk_guard): New variable.
(__libc_start_main): Set __stack_chk_guard to
_dl_setup_stack_chk_guard (), use THREAD_SET_STACK_GUARD if defined.
* sysdeps/generic/libc-tls.c (__libc_setup_tls): Remove all
traces of TLS_INIT_TP_EXPENSIVE.
* debug/Versions (libc): Export __stack_chk_fail@@GLIBC_2.4.
* debug/Makefile (routines): Add stack_chk_fail.
(static-only-routines): Add stack_chk_fail_local.
* debug/stack_chk_fail_local.c: New file.
* debug/stack_chk_fail.c: New file.
* elf/Makefile: Add rules to build and run tst-stackguard1{,-static}
tests.
* elf/tst-stackguard1.c: New file.
* elf/tst-stackguard1-static.c: New file.
* elf/stackguard-macros.h: New file.
2003-06-11 Jakub Jelinek <jakub@redhat.com>
* elf/Versions (libc): Add _dl_open_hook@GLIBC_PRIVATE.
* elf/dl-libc.c (struct dl_open_hook): New.
(_dl_open_hook): New variable.
(do_dlsym_private): New function.
(__libc_dlopen_mode) [!SHARED]: Lookup _dl_open_hook@GLIBC_PRIVATE
and initialize it if found.
(__libc_dlopen_mode) [SHARED]: If _dl_open_hook is non-NULL,
call dlopen_mode hook.
(__libc_dlsym) [SHARED]: If _dl_open_hook is non-NULL,
call dlsym hook.
(__libc_dlclose) [SHARED]: If _dl_open_hook is non-NULL,
call dlclose hook.
members to the end, so a libpthread compiled with !USE_TLS will still
find other members properly.
* sysdeps/i386/i486/bits/string.h (__strcpy_g): Add dummy output
operand for DEST memory. Fix dummy input operand to use SRC.
Reported by Davin McCall <davmac@ozonline.com.au>.
* sysdeps/generic/libc-tls.c (__libc_setup_tls): Account for TCB
alignment when initializing the DTV entry.
* elf/dl-load.c (_dl_map_object_from_fd): If we hit a TLS segment
when TLS has not been set up, try to set it up if we can.
* elf/tst-tls4.c: Revert last change.
* elf/tst-tls5.c: Likewise.
* elf/tst-tls6.c: Likewise.
* elf/tst-tls7.c: Likewise.
* elf/tst-tls8.c: Likewise.
* elf/tst-tls9.c: Likewise.
* sysdeps/generic/dl-tls.c [SHARED] (_dl_tls_setup): New function.
* sysdeps/generic/ldsodefs.h: Declare it.
* elf/Versions (ld: GLIBC_PRIVATE): Add it.
* sysdeps/generic/libc-tls.c (init_slotinfo): New static inline
function, broken out of __libc_setup_tls.
(init_static_tls): Likewise.
(__libc_setup_tls): Call them.
(_dl_tls_setup): New function, uses new subroutines.
* elf/dl-close.c (free_slotinfo): Make argument pointer to pointer.
Clear the pointer when returning true.
(libc_freeres_fn) [SHARED]: If GL(dl_initial_dtv) is null, free the
first element of the slotinfo list too.
* sysdeps/generic/dl-tls.c (_dl_determine_tlsoffset): Define only if
[SHARED].
* sysdeps/generic/ldsodefs.h (_dl_next_tls_modid): Declare as hidden.
(_dl_determine_tlsoffset): Likewise.
* elf/rtld.c (_dl_initial_error_catch_tsd): Renamed from
startup_error_tsd, made global.
(dl_main): Update initialization.
* elf/dl-tsd.c: Likewise.
* sysdeps/generic/ldsodefs.h: Declare it.
2002-08-20 Ulrich Drepper <drepper@redhat.com>
* elf/Versions [ld] (GLIBC_PRIVATE): Add _dl_get_tls_static_info.
* sysdeps/generic/dl-tls.c (_dl_allocate_tls_storage): Move dtv
memory allocation to...
(allocate_dtv): ...here. New function.
(_dl_allocate_tls): Change to take parameter. If parameter is non-NULL
call allocate_dtv instead of _dl_allocate_tls_storage.
(_dl_deallocate_tls): New parameter. Deallocate TCB only if true.
(_dl_get_tls_static_info): New function.
* sysdeps/generic/ldsodefs.h: Adjust prototypes of _dl_allocate_tls
and _dl_deallocate_tls. Add prototype for _dl_get_tls_static_info.
2002-02-12 Ulrich Drepper <drepper@redhat.com>
* sysdeps/generic/dl-tls.c (TLS_DTV_UNALLOCATED): Renamed from
TLS_DTV_UNALLOCATE.
(oom): New function.
(_dl_next_tls_modid): Rewrite to handle dl_tls_dtv_slotinfo_list.
(_dl_determine_tlsoffset): Likewise.
(_dl_allocate_tls): Likewise.
(__TLS_GET_ADDR): Define if not already defined.
(_dl_tls_symaddr): New function.
(allocate_and_init): New function.
(__tls_get_addr): Actually implement handling of generation counter
and deferred allocation.
* sysdeps/generic/ldsodefs.h (_rtld_global): Remove _dl_initimage_list,
add _dl_tls_dtv_slotinfo_list, _dl_tls_static_nelem, and
_dl_tls_generation.
Define TLS_SLOTINFO_SURPLUS and DTV_SURPLUS.
Declare _dl_tls_symaddr.
* sysdeps/i386/dl-tls.h: Disable __tls_get_addr handling unless
SHARED.
* include/link.h (struct link_map): Remove l_tls_nextimage and
l_tls_previmage.
* elf/dl-sym.c (_dl_sym): After successful lookup call _dl_tls_symaddr
instead of DL_SYMBOL_ADDRESS for STT_TLS symbols.
(_dl_vsym): Likewise.
* elf/rtld.c (_dl_start_final): Adjust initdtv initialization for new
layout.
(dl_main): Allow PT_TLS be present for empty segment. Remove
nextimage list handling. Instead add all modules using TLS to
dl_tls_dtv_slotinfo_list.
* elf/dl-open.c (dl_open_worker): After successfully loading all
objects add those with TLS to the dl_tls_dtv_slotinfo_list list.
* elf/dl-load.c (_dl_map_object_from_fd): If PT_TLS entry is for an
empty segment don't do anything. Remove handling of initimage list.
* elf/Versions [ld] (GLIBC_2.0): Add __libc_memalign.
(GLIBC_PRIVATE): Add _dl_tls_symaddr.
* elf/dl-minimal.c: Define __libc_memalign.
* elf/dl-support.c: Remove _dl_initimage_list. Add
_dl_tls_dtv_slotinfo_list, _dl_tls_static_nelem, and
_dl_tls_generation.
* include/stdlib.h: Declare __libc_memalign.
* elf/Makefile: Add rules to build and run tst-tls4 and tst-tls5.
* elf/tst-tls4.c: New file.
* elf/tst-tls5.c: New file.
* elf/tst-tlsmod2.c: New file.
* elf/tls-macros.h: asms using ___tls_get_addr destroy %ecx and %edx.
* elf/tst-tlsmod1.c: Don't define variables unles USE_TLS.
* elf/tst-tls1.c: Use test-skeleton.c.
* elf/tst-tls2.c: Likewise.
* elf/tst-tls3.c: Likewise.
* elf/dl-conflict.c (RESOLVE_MAP): Return NULL not 0.
* sysdeps/mips/machine-gmon.h: Update MCOUNT for current GCC behavior.
