diff options
Diffstat (limited to 'lldb/source/Plugins/Process/POSIX/NativeProcessELF.cpp')
| -rw-r--r-- | lldb/source/Plugins/Process/POSIX/NativeProcessELF.cpp | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/lldb/source/Plugins/Process/POSIX/NativeProcessELF.cpp b/lldb/source/Plugins/Process/POSIX/NativeProcessELF.cpp new file mode 100644 index 0000000000000..058dc5ae23382 --- /dev/null +++ b/lldb/source/Plugins/Process/POSIX/NativeProcessELF.cpp @@ -0,0 +1,178 @@ +//===-- 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 = std::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; +} + +template <typename T> +llvm::Expected<SVR4LibraryInfo> +NativeProcessELF::ReadSVR4LibraryInfo(lldb::addr_t link_map_addr) { + ELFLinkMap<T> link_map; + size_t bytes_read; + auto error = + ReadMemory(link_map_addr, &link_map, sizeof(link_map), bytes_read); + if (!error.Success()) + return error.ToError(); + + char name_buffer[PATH_MAX]; + llvm::Expected<llvm::StringRef> string_or_error = ReadCStringFromMemory( + link_map.l_name, &name_buffer[0], sizeof(name_buffer), bytes_read); + if (!string_or_error) + return string_or_error.takeError(); + + SVR4LibraryInfo info; + info.name = string_or_error->str(); + info.link_map = link_map_addr; + info.base_addr = link_map.l_addr; + info.ld_addr = link_map.l_ld; + info.next = link_map.l_next; + + return info; +} + +llvm::Expected<std::vector<SVR4LibraryInfo>> +NativeProcessELF::GetLoadedSVR4Libraries() { + // Address of DT_DEBUG.d_ptr which points to r_debug + lldb::addr_t info_address = GetSharedLibraryInfoAddress(); + if (info_address == LLDB_INVALID_ADDRESS) + return llvm::createStringError(llvm::inconvertibleErrorCode(), + "Invalid shared library info address"); + // Address of r_debug + lldb::addr_t address = 0; + size_t bytes_read; + auto status = + ReadMemory(info_address, &address, GetAddressByteSize(), bytes_read); + if (!status.Success()) + return status.ToError(); + if (address == 0) + return llvm::createStringError(llvm::inconvertibleErrorCode(), + "Invalid r_debug address"); + // Read r_debug.r_map + lldb::addr_t link_map = 0; + status = ReadMemory(address + GetAddressByteSize(), &link_map, + GetAddressByteSize(), bytes_read); + if (!status.Success()) + return status.ToError(); + if (address == 0) + return llvm::createStringError(llvm::inconvertibleErrorCode(), + "Invalid link_map address"); + + std::vector<SVR4LibraryInfo> library_list; + while (link_map) { + llvm::Expected<SVR4LibraryInfo> info = + GetAddressByteSize() == 8 ? ReadSVR4LibraryInfo<uint64_t>(link_map) + : ReadSVR4LibraryInfo<uint32_t>(link_map); + if (!info) + return info.takeError(); + if (!info->name.empty() && info->base_addr != 0) + library_list.push_back(*info); + link_map = info->next; + } + + return library_list; +} + +} // namespace lldb_private |