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Diffstat (limited to 'contrib/llvm-project/lldb/source/Plugins/Process/POSIX/NativeProcessELF.cpp')
| -rw-r--r-- | contrib/llvm-project/lldb/source/Plugins/Process/POSIX/NativeProcessELF.cpp | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/contrib/llvm-project/lldb/source/Plugins/Process/POSIX/NativeProcessELF.cpp b/contrib/llvm-project/lldb/source/Plugins/Process/POSIX/NativeProcessELF.cpp new file mode 100644 index 000000000000..559b16c8fd69 --- /dev/null +++ b/contrib/llvm-project/lldb/source/Plugins/Process/POSIX/NativeProcessELF.cpp @@ -0,0 +1,110 @@ +//===-- NativeProcessELF.cpp ---------------------------------- -*- C++ -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +#include "NativeProcessELF.h" + +#include "lldb/Utility/DataExtractor.h" + +namespace lldb_private { + +llvm::Optional<uint64_t> +NativeProcessELF::GetAuxValue(enum AuxVector::EntryType type) { + if (m_aux_vector == nullptr) { + auto buffer_or_error = GetAuxvData(); + if (!buffer_or_error) + return llvm::None; + DataExtractor auxv_data(buffer_or_error.get()->getBufferStart(), + buffer_or_error.get()->getBufferSize(), + GetByteOrder(), GetAddressByteSize()); + m_aux_vector = llvm::make_unique<AuxVector>(auxv_data); + } + + return m_aux_vector->GetAuxValue(type); +} + +lldb::addr_t NativeProcessELF::GetSharedLibraryInfoAddress() { + if (!m_shared_library_info_addr.hasValue()) { + if (GetAddressByteSize() == 8) + m_shared_library_info_addr = + GetELFImageInfoAddress<llvm::ELF::Elf64_Ehdr, llvm::ELF::Elf64_Phdr, + llvm::ELF::Elf64_Dyn>(); + else + m_shared_library_info_addr = + GetELFImageInfoAddress<llvm::ELF::Elf32_Ehdr, llvm::ELF::Elf32_Phdr, + llvm::ELF::Elf32_Dyn>(); + } + + return m_shared_library_info_addr.getValue(); +} + +template <typename ELF_EHDR, typename ELF_PHDR, typename ELF_DYN> +lldb::addr_t NativeProcessELF::GetELFImageInfoAddress() { + llvm::Optional<uint64_t> maybe_phdr_addr = + GetAuxValue(AuxVector::AUXV_AT_PHDR); + llvm::Optional<uint64_t> maybe_phdr_entry_size = + GetAuxValue(AuxVector::AUXV_AT_PHENT); + llvm::Optional<uint64_t> maybe_phdr_num_entries = + GetAuxValue(AuxVector::AUXV_AT_PHNUM); + if (!maybe_phdr_addr || !maybe_phdr_entry_size || !maybe_phdr_num_entries) + return LLDB_INVALID_ADDRESS; + lldb::addr_t phdr_addr = *maybe_phdr_addr; + size_t phdr_entry_size = *maybe_phdr_entry_size; + size_t phdr_num_entries = *maybe_phdr_num_entries; + + // Find the PT_DYNAMIC segment (.dynamic section) in the program header and + // what the load bias by calculating the difference of the program header + // load address and its virtual address. + lldb::offset_t load_bias; + bool found_load_bias = false; + lldb::addr_t dynamic_section_addr = 0; + uint64_t dynamic_section_size = 0; + bool found_dynamic_section = false; + ELF_PHDR phdr_entry; + for (size_t i = 0; i < phdr_num_entries; i++) { + size_t bytes_read; + auto error = ReadMemory(phdr_addr + i * phdr_entry_size, &phdr_entry, + sizeof(phdr_entry), bytes_read); + if (!error.Success()) + return LLDB_INVALID_ADDRESS; + if (phdr_entry.p_type == llvm::ELF::PT_PHDR) { + load_bias = phdr_addr - phdr_entry.p_vaddr; + found_load_bias = true; + } + + if (phdr_entry.p_type == llvm::ELF::PT_DYNAMIC) { + dynamic_section_addr = phdr_entry.p_vaddr; + dynamic_section_size = phdr_entry.p_memsz; + found_dynamic_section = true; + } + } + + if (!found_load_bias || !found_dynamic_section) + return LLDB_INVALID_ADDRESS; + + // Find the DT_DEBUG entry in the .dynamic section + dynamic_section_addr += load_bias; + ELF_DYN dynamic_entry; + size_t dynamic_num_entries = dynamic_section_size / sizeof(dynamic_entry); + for (size_t i = 0; i < dynamic_num_entries; i++) { + size_t bytes_read; + auto error = ReadMemory(dynamic_section_addr + i * sizeof(dynamic_entry), + &dynamic_entry, sizeof(dynamic_entry), bytes_read); + if (!error.Success()) + return LLDB_INVALID_ADDRESS; + // Return the &DT_DEBUG->d_ptr which points to r_debug which contains the + // link_map. + if (dynamic_entry.d_tag == llvm::ELF::DT_DEBUG) { + return dynamic_section_addr + i * sizeof(dynamic_entry) + + sizeof(dynamic_entry.d_tag); + } + } + + return LLDB_INVALID_ADDRESS; +} + +} // namespace lldb_private
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