Wean mtrace away from the malloc hooks and move them into the debug
DSO. Split the API away from the implementation so that we can add
the API to libc.so as well as libc_malloc_debug.so, with the libc
implementations being empty.
Update localplt data since memalign no longer has any callers after
this change.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-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 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.
libpthread used to have its own vfork implementation that differed
from libc's only in having a pointless micro-optimization. There is
no longer any use to having a separate copy in libpthread, but the
historical ABI requires a compatibility shim. microblaze was trying
to be slightly too clever about how it did this, and tickled a linker
bug. The linker bug should get fixed eventually, but there's no
reason for us to keep tickling it in the meantime.
This doesn't reuse the generic pt-vfork.c because microblaze doesn't
have IFUNC support yet, and it doesn't reuse aarch64/pt-vfork.c
because that fails to generate a tailcall (with GCC 7.1.1).
* sysdeps/unix/sysv/linux/microblaze/pt-vfork.S: Don't include
alpha/pt-vfork.S. Provide own compat shim for vfork and __vfork.
* sysdeps/unix/sysv/linux/microblaze/vfork.S: Add __libc_vfork alias.
* sysdeps/unix/sysv/linux/microblaze/localplt.data:
libpthread.so no longer references __errno_location.
This patch adds internal alias for __pread, __pread64, and __pwrite
following the already in place one for __pwrite64. This is not used
in any implementation but on microblaze on preadv/pwritev fallback
(since it does not define __ASSUME_PREADV).
In fact it was signaled by commit c35db50ff5 which update the expected
localptl.data for the architecture based on resulted value. This patch
updates the plt for microblaze now that p{read,write}{64} are correctly
routed to use internal alias.
Checked on x86_64-linux-gnu and a build for all supported architectures
(no all variants although).
* include/unistd.h (__pread): Add libc_hidden_proto.
(__pread64): Likewise.
(__pwrite): Likewise.
* sysdeps/unix/sysv/linux/microblaze/localplt.data [libc.so]
(__pread64): Remove.
* sysdeps/unix/sysv/linux/pread.c (__pread64): Add libc_hidden_weak.
* sysdeps/unix/sysv/linux/pread64.c (__pread64): Likewise.
* sysdeps/unix/sysv/linux/pwrite.c (__pwrite): Likewise.
This patch updates the MicroBlaze localplt.data based on the results
of a build with build-many-glibcs.py. This is simply an empirical
update; quite possibly the port could be optimized to remove more
local PLT entry usage.
Tested (compilation tests) with build-many-glibcs.py.
* sysdeps/unix/sysv/linux/microblaze/localplt.data (__pread64):
Add libc.so PLT entry.
(__tls_get_addr): Make ld.so PLT entry optional.
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.
For maximum paranoia we run ld.so through the normal set
of tests for all of the shared libraries. This includes
running ld.so through check-localplt, check-textrel, and
check-execstack. While none of these should trigger any
failures given the way ld.so is built, it might possibly
fail if a developer does something wrong. This paranoia
was triggered by a discussion over the use of __strcpy
vs. strcpy [1] and if the symbol could leak and use the
libc.so version.
The check-localplt test fails right away because localplt.data
needs updating for all arches. By default we add 6 new symbols:
__tls_get_addr, __libc_memalign, malloc, calloc, realloc and
free. Other machines like i386, power, and s390 require some
different symbol sets e.g. ___tls_get_addr vs. __tls_get_addr
for i386.
Verified for i386
Verified for x86_64
Verified for ppc32
Verified for ppc64
Verified for ppc64le
Verified for arm
Verified for aarch64
Verified for s390
Verified for s390x
Guessed for alpha
Guessed for ia64
Guessed for m68k
Guessed for microblaze
Guessed for sparc32
Guessed for sparc64
Defaults for sh
Defaults for mips
Defaults for hppa
Defaults for tile
Machine manintainers notified to double check the data
used in localplt.data.
[1] https://sourceware.org/ml/libc-alpha/2014-10/msg00548.html
