/*
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* Copyright (C) 2015 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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#pragma once
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#include "linker.h"
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#include <string.h>
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const size_t RELOCATION_GROUPED_BY_INFO_FLAG = 1;
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const size_t RELOCATION_GROUPED_BY_OFFSET_DELTA_FLAG = 2;
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const size_t RELOCATION_GROUPED_BY_ADDEND_FLAG = 4;
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const size_t RELOCATION_GROUP_HAS_ADDEND_FLAG = 8;
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class plain_reloc_iterator {
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#if defined(USE_RELA)
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typedef ElfW(Rela) rel_t;
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#else
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typedef ElfW(Rel) rel_t;
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#endif
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public:
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plain_reloc_iterator(rel_t* rel_array, size_t count)
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: begin_(rel_array), end_(begin_ + count), current_(begin_) {}
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bool has_next() {
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return current_ < end_;
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}
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rel_t* next() {
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return current_++;
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}
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private:
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rel_t* const begin_;
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rel_t* const end_;
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rel_t* current_;
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DISALLOW_COPY_AND_ASSIGN(plain_reloc_iterator);
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};
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template <typename decoder_t>
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class packed_reloc_iterator {
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#if defined(USE_RELA)
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typedef ElfW(Rela) rel_t;
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#else
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typedef ElfW(Rel) rel_t;
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#endif
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public:
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explicit packed_reloc_iterator(decoder_t&& decoder)
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: decoder_(decoder) {
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// initialize fields
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memset(&reloc_, 0, sizeof(reloc_));
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relocation_count_ = decoder_.pop_front();
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reloc_.r_offset = decoder_.pop_front();
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relocation_index_ = 0;
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relocation_group_index_ = 0;
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group_size_ = 0;
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}
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bool has_next() const {
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return relocation_index_ < relocation_count_;
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}
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rel_t* next() {
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if (relocation_group_index_ == group_size_) {
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if (!read_group_fields()) {
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// Iterator is inconsistent state; it should not be called again
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// but in case it is let's make sure has_next() returns false.
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relocation_index_ = relocation_count_ = 0;
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return nullptr;
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}
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}
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if (is_relocation_grouped_by_offset_delta()) {
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reloc_.r_offset += group_r_offset_delta_;
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} else {
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reloc_.r_offset += decoder_.pop_front();
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}
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if (!is_relocation_grouped_by_info()) {
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reloc_.r_info = decoder_.pop_front();
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}
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#if defined(USE_RELA)
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if (is_relocation_group_has_addend() &&
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!is_relocation_grouped_by_addend()) {
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reloc_.r_addend += decoder_.pop_front();
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}
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#endif
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relocation_index_++;
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relocation_group_index_++;
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return &reloc_;
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}
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private:
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bool read_group_fields() {
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group_size_ = decoder_.pop_front();
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group_flags_ = decoder_.pop_front();
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if (is_relocation_grouped_by_offset_delta()) {
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group_r_offset_delta_ = decoder_.pop_front();
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}
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if (is_relocation_grouped_by_info()) {
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reloc_.r_info = decoder_.pop_front();
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}
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if (is_relocation_group_has_addend() &&
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is_relocation_grouped_by_addend()) {
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#if !defined(USE_RELA)
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// This platform does not support rela, and yet we have it encoded in android_rel section.
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DL_ERR("unexpected r_addend in android.rel section");
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return false;
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#else
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reloc_.r_addend += decoder_.pop_front();
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} else if (!is_relocation_group_has_addend()) {
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reloc_.r_addend = 0;
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#endif
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}
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relocation_group_index_ = 0;
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return true;
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}
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bool is_relocation_grouped_by_info() {
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return (group_flags_ & RELOCATION_GROUPED_BY_INFO_FLAG) != 0;
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}
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bool is_relocation_grouped_by_offset_delta() {
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return (group_flags_ & RELOCATION_GROUPED_BY_OFFSET_DELTA_FLAG) != 0;
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}
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bool is_relocation_grouped_by_addend() {
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return (group_flags_ & RELOCATION_GROUPED_BY_ADDEND_FLAG) != 0;
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}
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bool is_relocation_group_has_addend() {
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return (group_flags_ & RELOCATION_GROUP_HAS_ADDEND_FLAG) != 0;
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}
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decoder_t decoder_;
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size_t relocation_count_;
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size_t group_size_;
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size_t group_flags_;
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size_t group_r_offset_delta_;
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size_t relocation_index_;
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size_t relocation_group_index_;
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rel_t reloc_;
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};
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