//===- FuzzerShmem.h - shared memory interface ------------------*- C++ -* ===//

//

//                     The LLVM Compiler Infrastructure

//

// This file is distributed under the University of Illinois Open Source

// License. See LICENSE.TXT for details.

//

//===----------------------------------------------------------------------===//

// SharedMemoryRegion

//===----------------------------------------------------------------------===//

#ifndef LLVM_FUZZER_SHMEM_H

#define LLVM_FUZZER_SHMEM_H

#include <algorithm>

#include <cstring>

#include <string>

#include "FuzzerDefs.h"

namespace fuzzer {

class SharedMemoryRegion {

 public:

  bool Create(const char *Name);

  bool Open(const char *Name);

  bool Destroy(const char *Name);

  uint8_t *GetData() { return Data; }

  void PostServer() {Post(0);}

  void WaitServer() {Wait(0);}

  void PostClient() {Post(1);}

  void WaitClient() {Wait(1);}

  size_t WriteByteArray(const uint8_t *Bytes, size_t N) {

    assert(N <= kShmemSize - sizeof(N));

    memcpy(GetData(), &N, sizeof(N));

    memcpy(GetData() + sizeof(N), Bytes, N);

    assert(N == ReadByteArraySize());

    return N;

  }

  size_t ReadByteArraySize() {

    size_t Res;

    memcpy(&Res, GetData(), sizeof(Res));

    return Res;

  }

  uint8_t *GetByteArray() { return GetData() + sizeof(size_t); }

  bool IsServer() const { return Data && IAmServer; }

  bool IsClient() const { return Data && !IAmServer; }

private:

  static const size_t kShmemSize = 1 << 22;

  bool IAmServer;

  std::string Path(const char *Name);

  std::string SemName(const char *Name, int Idx);

  void Post(int Idx);

  void Wait(int Idx);

  bool Map(int fd);

  uint8_t *Data = nullptr;

  void *Semaphore[2];

};

extern SharedMemoryRegion SMR;

}  // namespace fuzzer

#endif  // LLVM_FUZZER_SHMEM_H