Commit Graph

9 Commits

Author SHA1 Message Date
Siddhesh Poyarekar
9dad716d4d mtrace: Wean away from malloc hooks
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>
2021-07-22 18:38:06 +05:30
Florian Weimer
3a0ecccb59 ld.so: Do not export free/calloc/malloc/realloc functions [BZ #25486]
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>
2020-02-15 11:01:23 +01:00
Florian Weimer
2449ae7b2d ld.so: Introduce struct dl_exception
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.
2017-08-10 16:54:57 +02:00
Florian Weimer
2d6ab5df3b Document and fix --enable-bind-now [BZ #21015] 2017-03-02 14:44:28 +01:00
Florian Weimer
b04beebf07 ld.so: Remove __libc_memalign
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.
2016-11-30 16:23:58 +01:00
Florian Weimer
9e78f6f6e7 Implement _dl_catch_error, _dl_signal_error in libc.so [BZ #16628]
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.
2016-11-30 15:59:57 +01:00
Joseph Myers
58d6b0d865 Update alpha localplt.data.
This patch updates alpha localplt.data so the localplt test passes in
my compile-only all-ABIs glibc testing.  The failures I see without
this patch are:

Missing required PLT reference: ld.so: __tls_get_addr
Missing required PLT reference: ld.so: free

Now, __tls_get_addr can be made optional.  For free, rather than
making it optional as in libc.so it seems better to mark all the
malloc-related symbols in both libc.so and ld.so as allowing an
R_ALPHA_GLOB_DAT relocation as an alternative to using a PLT entry, so
this patch does so.

Tested for alpha.

	* sysdeps/unix/sysv/linux/alpha/localplt.data: Make __tls_get_addr
	optional in ld.so.  Allow R_ALPHA_GLOB_DAT relocation for malloc,
	calloc, realloc, free, memalign and __libc_memalign rather than
	making them optional.
2016-11-08 23:41:51 +00:00
Carlos O'Donell
da53d6dbc2 Run check-localpltk/textrel/execstack over 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
2014-11-06 15:48:44 -05:00
Richard Henderson
bc89e9625f alpha: Move remaining files out of sysdeps/unix/sysv/linux/alpha/nptl/ 2014-05-23 11:20:48 -07:00