5a66490e3b
Make getauxval() work in .preinit_array. It still won't be usable for
ifuncs unless we can guarantee that the __loader_shared_globals relocation
is resolved before the ifunc calls [__bionic_]getauxval.
Define __bionic_getauxval for use in replacing calls to
KernelArgumentBlock::getauxval, which doesn't (and sometimes isn't allowed
to) access TLS variables like errno.
Bug: http://b/25751302
Test: bionic unit tests
Change-Id: I461feeaed7f43cfa2a2b6c34147194f0df82b516
Merged-In: I461feeaed7f43cfa2a2b6c34147194f0df82b516
(cherry picked from commit bdab4a2b97)
56 lines
2.1 KiB
C++
56 lines
2.1 KiB
C++
/*
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* Copyright (C) 2013 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <stddef.h>
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#include <sys/cdefs.h>
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#include <sys/auxv.h>
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#include <private/bionic_auxv.h>
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#include <private/bionic_globals.h>
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#include <elf.h>
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#include <errno.h>
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// This function needs to be safe to call before TLS is set up, so it can't
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// access errno or the stack protector.
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__attribute__((no_stack_protector))
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__LIBC_HIDDEN__ unsigned long __bionic_getauxval(unsigned long type, bool& exists) {
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for (ElfW(auxv_t)* v = __libc_shared_globals()->auxv; v->a_type != AT_NULL; ++v) {
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if (v->a_type == type) {
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exists = true;
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return v->a_un.a_val;
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}
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}
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exists = false;
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return 0;
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}
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extern "C" unsigned long getauxval(unsigned long type) {
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bool exists;
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unsigned long result = __bionic_getauxval(type, exists);
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if (!exists) errno = ENOENT;
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return result;
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}
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