4809755c0f
The function searches for a TLS segment in a ElfXX_Phdr table. Bug: http://b/78026329 Test: bionic unit tests Change-Id: I221b13420d1a2da33fc2174b7dd256589f6ecfdb
96 lines
3.6 KiB
C++
96 lines
3.6 KiB
C++
/*
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* Copyright (C) 2019 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 "private/bionic_elf_tls.h"
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#include <async_safe/log.h>
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#include <sys/param.h>
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#include <unistd.h>
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#include "private/bionic_macros.h"
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#include "private/bionic_tls.h"
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// Search for a TLS segment in the given phdr table. Returns true if it has a
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// TLS segment and false otherwise.
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bool __bionic_get_tls_segment(const ElfW(Phdr)* phdr_table, size_t phdr_count,
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ElfW(Addr) load_bias, const char* mod_name,
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TlsSegment* out) {
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for (size_t i = 0; i < phdr_count; ++i) {
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const ElfW(Phdr)& phdr = phdr_table[i];
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if (phdr.p_type == PT_TLS) {
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// N.B. The size does not need to be a multiple of the alignment. With
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// ld.bfd (or after using binutils' strip), the TLS segment's size isn't
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// rounded up.
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size_t alignment = phdr.p_align;
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if (alignment == 0 || !powerof2(alignment)) {
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async_safe_fatal("error: \"%s\": TLS segment alignment is not a power of 2: %zu",
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mod_name, alignment);
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}
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// Bionic only respects TLS alignment up to one page.
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alignment = MIN(alignment, PAGE_SIZE);
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*out = TlsSegment {
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phdr.p_memsz,
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alignment,
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reinterpret_cast<void*>(load_bias + phdr.p_vaddr),
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phdr.p_filesz,
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};
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return true;
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}
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}
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return false;
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}
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void StaticTlsLayout::reserve_tcb() {
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offset_bionic_tcb_ = reserve_type<bionic_tcb>();
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}
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void StaticTlsLayout::reserve_bionic_tls() {
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offset_bionic_tls_ = reserve_type<bionic_tls>();
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}
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void StaticTlsLayout::finish_layout() {
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// Round the offset up to the alignment.
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offset_ = round_up_with_overflow_check(offset_, alignment_);
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}
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// The size is not required to be a multiple of the alignment. The alignment
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// must be a positive power-of-two.
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size_t StaticTlsLayout::reserve(size_t size, size_t alignment) {
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offset_ = round_up_with_overflow_check(offset_, alignment);
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const size_t result = offset_;
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if (__builtin_add_overflow(offset_, size, &offset_)) overflowed_ = true;
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alignment_ = MAX(alignment_, alignment);
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return result;
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}
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size_t StaticTlsLayout::round_up_with_overflow_check(size_t value, size_t alignment) {
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const size_t old_value = value;
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value = __BIONIC_ALIGN(value, alignment);
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if (value < old_value) overflowed_ = true;
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return value;
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}
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