dlerrror_run in elf/dl-libc.c needs to call GLRO (dl_catch_error)
from the base namespace, just like the exported dlerror
implementation.
Fixes commit b2964eb1d9 ("dlfcn:
Failures after dlmopen should not terminate process [BZ #24772]").
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Since commit 0c1c3a771e
("dlfcn: Move dlopen into libc") libdl.a is empty, so linking
against it is no longer necessary.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
The testcase elf/tst-tls9-static sometimes fails with:
cannot open 'tst-tlsmod5.so': tst-tlsmod5.so: cannot open shared object file: No such file or directory
cannot open 'tst-tlsmod6.so': tst-tlsmod6.so: cannot open shared object file: No such file or directory
After recent commit
6f1c701026
"dlfcn: Cleanups after -ldl is no longer required"
the libdl variable is not set anymore and thus the
dependencies were missing.
This commit removes the ELF constructor and internal variables from
dlfcn/dlfcn.c. The file now serves the same purpose as
nptl/libpthread-compat.c, so it is renamed to dlfcn/libdl-compat.c.
The use of libdl-shared-only-routines ensures that libdl.a is empty.
This commit adjusts the test suite not to use $(libdl). The libdl.so
symbolic link is no longer installed.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
The symbol was moved using scripts/move-symbol-to-libc.py.
In elf/Makefile, remove the $(libdl) dependency from testobj1.so
because it the unused libdl DSO now causes elf/tst-unused-deps to
fail.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Once libpthread is empty and no longer marked NODELETE, it no longer
can be used for testing.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
After static dlopen, a copy of ld.so is loaded into the inner
namespace, but that copy is not initialized at all. Some
architectures run into serious problems as result, which is why the
_dl_var_init mechanism was invented. With libpthread moving into
libc and parts into ld.so, more architectures impacted, so it makes
sense to switch to a generic mechanism which performs the partial
initialization.
As a result, getauxval now works after static dlopen (bug 20802).
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
(FYI, this is a repost of
https://sourceware.org/pipermail/libc-alpha/2019-July/105035.html now
that FSF papers have been signed and confirmed on FSF side).
This trivial patch attemps to fix BZ 24106. Basically the bash locally
used when building glibc on the host shall not leak on the installed
glibc, as the system where it is installed might be different and use
another bash location.
So I have looked for all occurences of @BASH@ or $(BASH) in installed
files, and replaced it by /bin/bash. This was suggested by Florian
Weimer in the bug report.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Test concurrent dlopen and pthread_create when the loaded modules have
TLS. This triggers dl-tls assertion failures more reliably than the
nptl/tst-stack4 test.
The dlopened module has 100 DT_NEEDED dependencies with TLS, they were
reused from an existing TLS test. The number of created threads during
dlopen depends on filesystem speed and hardware, but at most 3 threads
are alive at a time to limit resource usage.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
If libpthread is included in libc, it is not necessary to delay
initialization of the lock/unlock function pointers until libpthread
is loaded. This eliminates two unprotected function pointers
from _rtld_global and removes some initialization code from
libpthread.
Tested-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Previously, the source file nptl/cancellation.c was compiled multiple
times, for libc, libpthread, librt. This commit switches to a single
implementation, with new __pthread_enable_asynccancel@@GLIBC_PRIVATE,
__pthread_disable_asynccancel@@GLIBC_PRIVATE exports.
The almost-unused CANCEL_ASYNC and CANCEL_RESET macros are replaced
by LIBC_CANCEL_ASYNC and LIBC_CANCEL_ASYNC macros. They call the
__pthread_* functions unconditionally now. The macros are still
needed because shared code uses them; Hurd has different definitions.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
TLS_INIT_TP is processor-specific, so it is not a good place to
put thread library initialization code (it would have to be repeated
for all CPUs). Introduce __tls_init_tp as a separate function,
to be called immediately after TLS_INIT_TP. Move the existing
stack list setup code for NPTL to this function.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Commit 9e78f6f6e7 ("Implement
_dl_catch_error, _dl_signal_error in libc.so [BZ #16628]") has the
side effect that distinct namespaces, as created by dlmopen, now have
separate implementations of the rtld exception mechanism. This means
that the call to _dl_catch_error from libdl in a secondary namespace
does not actually install an exception handler because the
thread-local variable catch_hook in the libc.so copy in the secondary
namespace is distinct from that of the base namepace. As a result, a
dlsym/dlopen/... failure in a secondary namespace terminates the process
with a dynamic linker error because it looks to the exception handler
mechanism as if no handler has been installed.
This commit restores GLRO (dl_catch_error) and uses it to set the
handler in the base namespace.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
It's necessary to stub out __libc_disable_asynccancel and
__libc_enable_asynccancel via rtld-stubbed-symbols because the new
direct references to the unwinder result in symbol conflicts when the
rtld exception handling from libc is linked in during the construction
of librtld.map.
unwind-forcedunwind.c is merged into unwind-resume.c. libc now needs
the functions that were previously only used in libpthread.
The GLIBC_PRIVATE exports of __libc_longjmp and __libc_siglongjmp are
no longer needed, so switch them to hidden symbols.
The symbol __pthread_unwind_next has been moved using
scripts/move-symbol-to-libc.py.
Reviewed-by: Adhemerva Zanella <adhemerval.zanella@linaro.org>
The test dlopens a large number of modules with TLS, they are reused
from an existing test.
The test relies on the reuse of slotinfo entries after dlclose, without
bug 27135 fixed this needs a failing dlopen. With a slotinfo list that
has non-monotone increasing generation counters, bug 27136 can trigger.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Instead of passing GLIBC_TUNABLES via the environment, pass the
environment variable from parent to child. This allows us to test
multiple variables to ensure better coverage.
The test list currently only includes the case that's already being
tested. More tests will be added later.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
This does not change the emitted code since __libc_start_main does not
return, but is important for formal flags compliance.
This also cleans up the cosmetic inconsistency in the stack protector
flags in csu, especially the incorrect value of STACK_PROTECTOR_LEVEL.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
In this case, use the link map of the dynamic loader itself as
a replacement. This is more than just a hack: if we ever support
DT_RUNPATH/DT_RPATH for the dynamic loader, reporting it for
ld.so --help (without further command line arguments) would be the
right thing to do.
Fixes commit 3324213125 ("elf: Always
set l in _dl_init_paths (bug 23462)").
After d1d5471579 ("Remove dead
DL_DST_REQ_STATIC code.") we always setup the link map l to make the
static and shared cases the same. The bug is that in elf/dl-load.c
(_dl_init_paths) we conditionally set l only in the #ifdef SHARED
case, but unconditionally use it later. The simple solution is to
remove the #ifdef SHARED conditional, because it's no longer needed,
and unconditionally setup l for both the static and shared cases. A
regression test is added to run a static binary with
LD_LIBRARY_PATH='$ORIGIN' which crashes before the fix and runs after
the fix.
Co-Authored-By: Florian Weimer <fweimer@redhat.com>
The existing code specifies -Wl,--defsym=malloc=0 and other malloc.os
definitions before libc_pic.a so that libc_pic.a(malloc.os) is not
fetched. This trick is used to avoid multiple definition errors which
would happen as a chain result:
dl-allobjs.os has an undefined __libc_scratch_buffer_set_array_size
__libc_scratch_buffer_set_array_size fetches libc_pic.a(scratch_buffer_set_array_size.os)
libc_pic.a(scratch_buffer_set_array_size.os) has an undefined free
free fetches libc_pic.a(malloc.os)
libc_pic.a(malloc.os) has an undefined __libc_message
__libc_message fetches libc_pic.a(libc_fatal.os)
libc_fatal.os will cause a multiple definition error (__GI___libc_fatal)
>>> defined at dl-fxstatat64.c
>>> /tmp/p/glibc/Release/elf/dl-allobjs.os:(__GI___libc_fatal)
>>> defined at libc_fatal.c
>>> libc_fatal.os:(.text+0x240) in archive /tmp/p/glibc/Release/libc_pic.a
LLD processes --defsym after all input files, so this trick does not
suppress multiple definition errors with LLD. Split the step into two
and use an object file to make the intention more obvious and make LLD
work.
This is conceptually more appropriate because --defsym defines a SHN_ABS
symbol while a normal definition is relative to the image base.
See https://sourceware.org/pipermail/libc-alpha/2020-March/111910.html
for discussions about the --defsym semantics.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
elf/tst-prelink-cmp was initially added for x86 (commit fe534fe898) to validate
the fix for Bug 19178, and later applied to all architectures that use GLOB_DAT
relocations (commit 89569c8bb6). However, that bug only affected targets that
handle GLOB_DAT relocations as ELF_TYPE_CLASS_EXTERN_PROTECTED_DATA, so the test
should only apply to targets defining DL_EXTERN_PROTECTED_DATA, which gates the
usage of the elf type class above. For all other targets not meeting that
criteria, the test now returns with UNSUPPORTED status.
Fixes the test on POWER10 processors, which started using R_PPC64_GLOB_DAT.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
On x86, ifuncmain6pie failed with:
[hjl@gnu-cfl-2 build-i686-linux]$ ./elf/ifuncmain6pie --direct
./elf/ifuncmain6pie: IFUNC symbol 'foo' referenced in '/export/build/gnu/tools-build/glibc-32bit/build-i686-linux/elf/ifuncmod6.so' is defined in the executable and creates an unsatisfiable circular dependency.
[hjl@gnu-cfl-2 build-i686-linux]$ readelf -rW elf/ifuncmod6.so | grep foo
00003ff4 00000706 R_386_GLOB_DAT 0000400c foo_ptr
00003ff8 00000406 R_386_GLOB_DAT 00000000 foo
0000400c 00000401 R_386_32 00000000 foo
[hjl@gnu-cfl-2 build-i686-linux]$
Remove non-JUMP_SLOT relocations against foo in ifuncmod6.so, which
trigger the circular IFUNC dependency, and build ifuncmain6pie with
-Wl,-z,lazy.
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
_dl_map_object_deps always sorts the initially loaded object first
during dependency sorting. This means it is relocated last in
dl_open_worker. This results in crashes in IFUNC resolvers without
lazy bindings if libraries are preloaded that refer to IFUNCs in
libc.so.6: the resolvers are called when libc.so.6 has not been
relocated yet, so references to _rtld_global_ro etc. crash.
The fix is to check against the libc.so.6 link map recorded by the
__libc_early_init framework, and let it participate in the dependency
sort.
This fixes bug 20972.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Subdirectories z13, z14, z15 can be selected, mostly based on the
level of support for vector instructions.
Co-Authored-By: Stefan Liebler <stli@linux.ibm.com>
The misattributed dependencies can cause failures in parallel testing
if the dependencies have not been built yet.
Fixes commit a332bd1518
("elf: Add elf/tst-dlopenfail-2 [BZ #25396]").
This recognizes the DL_CACHE_HWCAP_EXTENSION flag in cache entries,
and picks the supported cache entry with the highest priority.
The elf/tst-glibc-hwcaps-prepend-cache test documents a non-desired
aspect of the current cache implementation: If the cache selects a DSO
that does not exist on disk, _dl_map_object falls back to open_path,
which may or may not find an alternative implementation. This is an
existing limitation that also applies to the legacy hwcaps processing
for ld.so.cache.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This simplifies the string table construction in elf/cache.c
because there is no more need to keep track of offsets explicitly;
the string table implementation does this internally.
This change slightly reduces the size of the cache on disk. The
file format does not change as a result. The strings are
null-terminated, without explicit length, so tail merging is
transparent to readers.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This will be used in ldconfig to reduce the ld.so.cache size slightly.
Tail merging is an optimization where a pointer points into another
string if the first string is a suffix of the second string.
The hash function FNV-1a was chosen because it is simple and achieves
good dispersion even for short strings (so that the hash table bucket
count can be a power of two). It is clearly superior to the hsearch
hash and the ELF hash in this regard.
The hash table uses chaining for collision resolution.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This hacks non-power-set processing into _dl_important_hwcaps.
Once the legacy hwcaps handling goes away, the subdirectory
handling needs to be reworked, but it is premature to do this
while both approaches are still supported.
ld.so supports two new arguments, --glibc-hwcaps-prepend and
--glibc-hwcaps-mask. Each accepts a colon-separated list of
glibc-hwcaps subdirectory names. The prepend option adds additional
subdirectories that are searched first, in the specified order. The
mask option restricts the automatically selected subdirectories to
those listed in the option argument. For example, on systems where
/usr/lib64 is on the library search path,
--glibc-hwcaps-prepend=valgrind:debug causes the dynamic loader to
search the directories /usr/lib64/glibc-hwcaps/valgrind and
/usr/lib64/glibc-hwcaps/debug just before /usr/lib64 is searched.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
On GNU/Hurd we not only need $(common-objpfx) in LD_LIBRARY_PATH when loading
dynamic objects, but also $(common-objpfx)/mach and $(common-objpfx)/hurd. This
adds an ld-library-path variable to be used as LD_LIBRARY_PATH basis in
Makefiles, and a sysdep-ld-library-path variable for sysdeps to add some
more paths, here mach/ and hurd/.
Now __thread_gscope_wait (the function behind THREAD_GSCOPE_WAIT,
formerly __wait_lookup_done) can be implemented directly in ld.so,
eliminating the unprotected GL (dl_wait_lookup_done) function
pointer.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This requires defining a macro for the full path, matching the
-Wl,--dynamic-link= arguments used for linking glibc programs,
and ldd script.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Also add a comment to elf/Makefile, explaining why we cannot use
config.status for autoconf template processing.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
The generic version is parallel to _dl_writev. It cannot use
_dl_writev directly because the errno value needs to be obtained
under a lock.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This functionality does not seem to be useful since static dlopen
is mostly used for iconv/character set conversion and NSS support.
gconv modules are loaded with full paths anyway, so that the
HWCAP subdirectory logic does not apply.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Make the computation in elf/dl-tls.c more transparent, and add
an explicit test for the historic value.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
On some targets static TLS surplus area can be used opportunistically
for dynamically loaded modules such that the TLS access then becomes
faster (TLSDESC and powerpc TLS optimization). However we don't want
all surplus TLS to be used for this optimization because dynamically
loaded modules with initial-exec model TLS can only use surplus TLS.
The new contract for surplus static TLS use is:
- libc.so can have up to 192 bytes of IE TLS,
- other system libraries together can have up to 144 bytes of IE TLS.
- Some "optional" static TLS is available for opportunistic use.
The optional TLS is now tunable: rtld.optional_static_tls, so users
can directly affect the allocated static TLS size. (Note that module
unloading with dlclose does not reclaim static TLS. After the optional
TLS runs out, TLS access is no longer optimized to use static TLS.)
The default setting of rtld.optional_static_tls is 512 so the surplus
TLS is 3*192 + 4*144 + 512 = 1664 by default, the same as before.
Fixes BZ #25051.
Tested on aarch64-linux-gnu and x86_64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
The variable is placed in libc.so, and it can be true only in
an outer libc, not libcs loaded via dlmopen or static dlopen.
Since thread creation from inner namespaces does not work,
pthread_create can update __libc_single_threaded directly.
Using __libc_early_init and its initial flag, implementation of this
variable is very straightforward. A future version may reset the flag
during fork (but not in an inner namespace), or after joining all
threads except one.
Reviewed-by: DJ Delorie <dj@redhat.com>
This was originally added to support binutils older than version
2.22:
<https://sourceware.org/ml/libc-alpha/2010-12/msg00051.html>
Since 2.22 is older than the minimum required binutils version
for building glibc, we no longer need this. (The changes do
not impact the statically linked startup code.)
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>
GNU ld and gold's -Map include a line like:
path/to/build/libc_pic.a(check_fds.os)
lld -Map does not have the archive member list, but we can still derive the
members from the following output
VMA LMA Size Align Out In Symbol
...
1a1c0 1a1c0 e2 16 path/to/build/libc_pic.a(check_fds.os):(.text)
