forked from OSchip/llvm-project
110 lines
4.0 KiB
C++
110 lines
4.0 KiB
C++
//===-- NativeProcessELF.cpp ---------------------------------- -*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "NativeProcessELF.h"
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#include "lldb/Utility/DataExtractor.h"
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namespace lldb_private {
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llvm::Optional<uint64_t>
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NativeProcessELF::GetAuxValue(enum AuxVector::EntryType type) {
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if (m_aux_vector == nullptr) {
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auto buffer_or_error = GetAuxvData();
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if (!buffer_or_error)
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return llvm::None;
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DataExtractor auxv_data(buffer_or_error.get()->getBufferStart(),
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buffer_or_error.get()->getBufferSize(),
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GetByteOrder(), GetAddressByteSize());
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m_aux_vector = llvm::make_unique<AuxVector>(auxv_data);
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}
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return m_aux_vector->GetAuxValue(type);
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}
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lldb::addr_t NativeProcessELF::GetSharedLibraryInfoAddress() {
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if (!m_shared_library_info_addr.hasValue()) {
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if (GetAddressByteSize() == 8)
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m_shared_library_info_addr =
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GetELFImageInfoAddress<llvm::ELF::Elf64_Ehdr, llvm::ELF::Elf64_Phdr,
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llvm::ELF::Elf64_Dyn>();
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else
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m_shared_library_info_addr =
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GetELFImageInfoAddress<llvm::ELF::Elf32_Ehdr, llvm::ELF::Elf32_Phdr,
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llvm::ELF::Elf32_Dyn>();
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}
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return m_shared_library_info_addr.getValue();
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}
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template <typename ELF_EHDR, typename ELF_PHDR, typename ELF_DYN>
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lldb::addr_t NativeProcessELF::GetELFImageInfoAddress() {
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llvm::Optional<uint64_t> maybe_phdr_addr =
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GetAuxValue(AuxVector::AUXV_AT_PHDR);
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llvm::Optional<uint64_t> maybe_phdr_entry_size =
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GetAuxValue(AuxVector::AUXV_AT_PHENT);
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llvm::Optional<uint64_t> maybe_phdr_num_entries =
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GetAuxValue(AuxVector::AUXV_AT_PHNUM);
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if (!maybe_phdr_addr || !maybe_phdr_entry_size || !maybe_phdr_num_entries)
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return LLDB_INVALID_ADDRESS;
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lldb::addr_t phdr_addr = *maybe_phdr_addr;
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size_t phdr_entry_size = *maybe_phdr_entry_size;
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size_t phdr_num_entries = *maybe_phdr_num_entries;
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// Find the PT_DYNAMIC segment (.dynamic section) in the program header and
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// what the load bias by calculating the difference of the program header
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// load address and its virtual address.
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lldb::offset_t load_bias;
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bool found_load_bias = false;
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lldb::addr_t dynamic_section_addr = 0;
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uint64_t dynamic_section_size = 0;
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bool found_dynamic_section = false;
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ELF_PHDR phdr_entry;
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for (size_t i = 0; i < phdr_num_entries; i++) {
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size_t bytes_read;
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auto error = ReadMemory(phdr_addr + i * phdr_entry_size, &phdr_entry,
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sizeof(phdr_entry), bytes_read);
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if (!error.Success())
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return LLDB_INVALID_ADDRESS;
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if (phdr_entry.p_type == llvm::ELF::PT_PHDR) {
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load_bias = phdr_addr - phdr_entry.p_vaddr;
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found_load_bias = true;
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}
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if (phdr_entry.p_type == llvm::ELF::PT_DYNAMIC) {
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dynamic_section_addr = phdr_entry.p_vaddr;
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dynamic_section_size = phdr_entry.p_memsz;
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found_dynamic_section = true;
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}
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}
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if (!found_load_bias || !found_dynamic_section)
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return LLDB_INVALID_ADDRESS;
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// Find the DT_DEBUG entry in the .dynamic section
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dynamic_section_addr += load_bias;
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ELF_DYN dynamic_entry;
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size_t dynamic_num_entries = dynamic_section_size / sizeof(dynamic_entry);
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for (size_t i = 0; i < dynamic_num_entries; i++) {
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size_t bytes_read;
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auto error = ReadMemory(dynamic_section_addr + i * sizeof(dynamic_entry),
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&dynamic_entry, sizeof(dynamic_entry), bytes_read);
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if (!error.Success())
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return LLDB_INVALID_ADDRESS;
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// Return the &DT_DEBUG->d_ptr which points to r_debug which contains the
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// link_map.
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if (dynamic_entry.d_tag == llvm::ELF::DT_DEBUG) {
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return dynamic_section_addr + i * sizeof(dynamic_entry) +
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sizeof(dynamic_entry.d_tag);
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}
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}
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return LLDB_INVALID_ADDRESS;
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}
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} // namespace lldb_private
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