ProcessElfCore.h

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//===-- ProcessElfCore.h ----------------------------------------*- 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
//
// Notes about Linux Process core dumps:
//  1) Linux core dump is stored as ELF file.
//  2) The ELF file's PT_NOTE and PT_LOAD segments describes the program's
//     address space and thread contexts.
//  3) PT_NOTE segment contains note entries which describes a thread context.
//  4) PT_LOAD segment describes a valid contiguous range of process address
//     space.
//===----------------------------------------------------------------------===//
 
#ifndef LLDB_SOURCE_PLUGINS_PROCESS_ELF_CORE_PROCESSELFCORE_H
#define LLDB_SOURCE_PLUGINS_PROCESS_ELF_CORE_PROCESSELFCORE_H
 
#include <functional>
#include <list>
#include <set>
#include <unordered_map>
#include <vector>
 
#include "lldb/Target/MemoryRegionInfo.h"
#include "lldb/Target/PostMortemProcess.h"
#include "lldb/Utility/Args.h"
#include "lldb/Utility/Status.h"
 
#include "Plugins/ObjectFile/ELF/ELFHeader.h"
#include "Plugins/Process/elf-core/RegisterUtilities.h"
 
struct ThreadData;
 
class ProcessElfCore : public lldb_private::PostMortemProcess {
public:
  // Constructors and Destructors
  static lldb::ProcessSP
  CreateInstance(lldb::TargetSP target_sp, lldb::ListenerSP listener_sp,
                 const lldb_private::FileSpec *crash_file_path,
                 bool can_connect);
 
  static void Initialize();
 
  static void Terminate();
 
  static llvm::StringRef GetPluginNameStatic() { return "elf-core"; }
 
  static llvm::StringRef GetPluginDescriptionStatic();
 
  // Constructors and Destructors
  ProcessElfCore(lldb::TargetSP target_sp, lldb::ListenerSP listener_sp,
                 const lldb_private::FileSpec &core_file);
 
  ~ProcessElfCore() override;
 
  // Check if a given Process
  bool CanDebug(lldb::TargetSP target_sp,
                bool plugin_specified_by_name) override;
 
  // Creating a new process, or attaching to an existing one
  lldb_private::Status DoLoadCore() override;
 
  lldb_private::DynamicLoader *GetDynamicLoader() override;
 
  // PluginInterface protocol
  llvm::StringRef GetPluginName() override { return GetPluginNameStatic(); }
 
  // Process Control
  lldb_private::Status DoDestroy() override;
 
  void RefreshStateAfterStop() override;
 
  lldb_private::Status WillResume() override {
    return lldb_private::Status::FromErrorStringWithFormatv(
        "error: {0} does not support resuming processes", GetPluginName());
  }
 
  // Process Queries
  bool IsAlive() override;
 
  bool WarnBeforeDetach() const override { return false; }
 
  // Process Memory
  size_t ReadMemory(lldb::addr_t addr, void *buf, size_t size,
                    lldb_private::Status &error) override;
 
  size_t DoReadMemory(lldb::addr_t addr, void *buf, size_t size,
                      lldb_private::Status &error) override;
 
  // We do not implement DoReadMemoryTags. Instead all the work is done in
  // ReadMemoryTags which avoids having to unpack and repack tags.
  llvm::Expected<std::vector<lldb::addr_t>> ReadMemoryTags(lldb::addr_t addr,
                                                           size_t len) override;
 
  lldb::addr_t GetImageInfoAddress() override;
 
  lldb_private::ArchSpec GetArchitecture();
 
  // Returns AUXV structure found in the core file
  lldb_private::DataExtractor GetAuxvData() override;
 
  std::optional<Process::CoreArgs> GetCoreFileArgs() override;
  bool GetProcessInfo(lldb_private::ProcessInstanceInfo &info) override;
 
protected:
  void Clear();
 
  bool DoUpdateThreadList(lldb_private::ThreadList &old_thread_list,
                          lldb_private::ThreadList &new_thread_list) override;
 
  lldb_private::Status
  DoGetMemoryRegionInfo(lldb::addr_t load_addr,
                        lldb_private::MemoryRegionInfo &region_info) override;
 
  bool SupportsMemoryTagging() override { return !m_core_tag_ranges.IsEmpty(); }
 
private:
  struct NT_FILE_Entry {
    lldb::addr_t start;
    lldb::addr_t end;
    lldb::addr_t file_ofs;
    std::string path;
  };
 
  // For ProcessElfCore only
  typedef lldb_private::Range<lldb::addr_t, lldb::addr_t> FileRange;
  typedef lldb_private::RangeDataVector<lldb::addr_t, lldb::addr_t, FileRange>
      VMRangeToFileOffset;
 
  lldb::ModuleSP m_core_module_sp;
  std::string m_dyld_plugin_name;
 
  // True if m_thread_contexts contains valid entries
  bool m_thread_data_valid = false;
 
  // Contain thread data read from NOTE segments
  std::vector<ThreadData> m_thread_data;
 
  // AUXV structure found from the NOTE segment
  lldb_private::DataExtractor m_auxv;
 
  // Address ranges found in the core
  VMRangeToFileOffset m_core_aranges;
 
  // Information for all mapped ranges, ordered by address.
  std::set<lldb_private::MemoryRegionInfo, std::less<>> m_core_range_infos;
 
  // Memory tag ranges found in the core
  VMRangeToFileOffset m_core_tag_ranges;
 
  // NT_FILE entries found from the NOTE segment
  std::vector<NT_FILE_Entry> m_nt_file_entries;
 
  // Map from file path to UUID for quick lookup
  std::unordered_map<std::string, lldb_private::UUID> m_uuids;
 
  // Executable name found from the ELF PRPSINFO
  std::string m_executable_name;
 
  // Command line args found from the ELF PRPSINFO (pr_psargs)
  Process::CoreArgs m_process_args;
  // Parse thread(s) data structures(prstatus, prpsinfo) from given NOTE segment
  llvm::Error ParseThreadContextsFromNoteSegment(
      const elf::ELFProgramHeader &segment_header,
      const lldb_private::DataExtractor &segment_data);
 
  // Returns number of thread contexts stored in the core file
  uint32_t GetNumThreadContexts();
 
  // Populate gnu uuid for each NT_FILE entry
  void UpdateBuildIdForNTFileEntries();
 
  // Complete memory region information after all program headers are parsed.
  void FinalizeMemoryRegionInfos();
 
  bool FindModuleUUID(lldb_private::ModuleSpec &spec) override;
 
  // Extract the executable module spec for the executable in this core file.
  bool GetMainExecutableModuleSpec(lldb_private::ModuleSpec &exe_spec);
 
  // Returns the value of certain type of note of a given start address
  lldb_private::UUID FindBuidIdInCoreMemory(lldb::addr_t address);
 
  // Parse a contiguous address range of the process from LOAD segment
  lldb::addr_t
  AddAddressRangeFromLoadSegment(const elf::ELFProgramHeader &header);
 
  // Parse a contiguous address range from a memory tag segment
  lldb::addr_t
  AddAddressRangeFromMemoryTagSegment(const elf::ELFProgramHeader &header);
 
  llvm::Expected<std::vector<lldb_private::CoreNote>>
  parseSegment(const lldb_private::DataExtractor &segment);
  llvm::Error parseFreeBSDNotes(llvm::ArrayRef<lldb_private::CoreNote> notes);
  llvm::Error parseNetBSDNotes(llvm::ArrayRef<lldb_private::CoreNote> notes);
  llvm::Error parseOpenBSDNotes(llvm::ArrayRef<lldb_private::CoreNote> notes);
  llvm::Error parseLinuxNotes(llvm::ArrayRef<lldb_private::CoreNote> notes);
 
  /// Find the NT_FILE entry that contains an address.
  std::optional<NT_FILE_Entry>
  GetNTFileEntryContainingAddress(lldb::addr_t addr);
  /// Intelligently find the NT_FILE entry for the executable's ELF header.
  std::optional<NT_FILE_Entry> GetNTFileEntryForExecutableELFHeader();
};
 
#endif // LLDB_SOURCE_PLUGINS_PROCESS_ELF_CORE_PROCESSELFCORE_H