libbacktrace/BacktraceOffline.h

/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef _LIBBACKTRACE_UNWIND_OFFLINE_H
#define _LIBBACKTRACE_UNWIND_OFFLINE_H

#include <libunwind.h>
#include <stdint.h>
#include <sys/types.h>
#include <ucontext.h>

#include <unordered_map>
#include <unordered_set>

#include <backtrace/Backtrace.h>

struct Space {
  uint64_t start;
  uint64_t end;
  const uint8_t* data;

  Space() {
    Clear();
  }

  void Clear();
  size_t Read(uint64_t addr, uint8_t* buffer, size_t size);
};

struct DebugFrameInfo {
  bool is_eh_frame;
  struct EhFrame {
    uint64_t eh_frame_hdr_vaddr;
    uint64_t eh_frame_vaddr;
    uint64_t fde_table_offset_in_eh_frame_hdr;
    std::vector<uint8_t> eh_frame_hdr_data;
    std::vector<uint8_t> eh_frame_data;
    struct ProgramHeader {
      uint64_t vaddr;
      uint64_t file_offset;
      uint64_t file_size;
    };
    std::vector<ProgramHeader> program_headers;
  } eh_frame;
};

class BacktraceOffline : public Backtrace {
 public:
  BacktraceOffline(pid_t pid, pid_t tid, BacktraceMap* map, const backtrace_stackinfo_t& stack,
                   bool cache_file)
      : Backtrace(pid, tid, map),
        cache_file_(cache_file),
        context_(nullptr),
        last_debug_frame_(nullptr) {
    stack_space_.start = stack.start;
    stack_space_.end = stack.end;
    stack_space_.data = stack.data;
  }

  virtual ~BacktraceOffline() {
    if (last_debug_frame_ != nullptr) {
      delete last_debug_frame_;
    }
  }

  bool Unwind(size_t num_ignore_frames, ucontext_t* context) override;

  bool ReadWord(uintptr_t ptr, word_t* out_value) override;

  size_t Read(uintptr_t addr, uint8_t* buffer, size_t bytes) override;

  bool FindProcInfo(unw_addr_space_t addr_space, uint64_t ip, unw_proc_info_t* proc_info,
                    int need_unwind_info);

  bool ReadReg(size_t reg_index, uint64_t* value);

 protected:
  std::string GetFunctionNameRaw(uintptr_t pc, uintptr_t* offset) override;
  DebugFrameInfo* GetDebugFrameInFile(const std::string& filename);

  static std::unordered_map<std::string, std::unique_ptr<DebugFrameInfo>> debug_frames_;
  static std::unordered_set<std::string> debug_frame_missing_files_;

  bool cache_file_;
  ucontext_t* context_;
  Space eh_frame_hdr_space_;
  Space eh_frame_space_;
  Space stack_space_;
  DebugFrameInfo* last_debug_frame_;
};

#endif  // _LIBBACKTRACE_BACKTRACE_OFFLINE_H