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29496b3103
The rtld-audit interfaces introduces a slowdown due to enabling
profiling instrumentation (as if LD_AUDIT implied LD_PROFILE).
However, instrumenting is only necessary if one of audit libraries
provides PLT callbacks (la_pltenter or la_pltexit symbols). Otherwise,
the slowdown can be avoided.
The following patch adjusts the logic that enables profiling to iterate
over all audit modules and check if any of those provides a PLT hook.
To keep la_symbind to work even without PLT callbacks, _dl_fixup now
calls the audit callback if the modules implements it.
Co-authored-by: Alexander Monakov <amonakov@ispras.ru>
Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
(cherry picked from commit 063f9ba220)
Resolved conflicts:
NEWS
elf/Makefile
39 lines
1.3 KiB
C
39 lines
1.3 KiB
C
/* Check if DT_AUDIT a module without la_plt{enter,exit} symbols does not incur
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in profiling (BZ#15533).
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Copyright (C) 2021 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <link.h>
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#include <support/xdlfcn.h>
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#include <support/check.h>
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static int
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do_test (void)
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{
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void *h = xdlopen ("tst-auditmod19a.so", RTLD_NOW);
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struct link_map *lmap;
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TEST_VERIFY_EXIT (dlinfo (h, RTLD_DI_LINKMAP, &lmap) == 0);
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/* The internal array is only allocated if profiling is enabled. */
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TEST_VERIFY (lmap->l_reloc_result == NULL);
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return 0;
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}
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#include <support/test-driver.c>
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