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      1 /*
      2  * Copyright (C) 2016 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef LIBMEMUNREACHABLE_SCOPED_PIPE_H_
     18 #define LIBMEMUNREACHABLE_SCOPED_PIPE_H_
     19 
     20 #include <unistd.h>
     21 
     22 #include "log.h"
     23 
     24 class ScopedPipe {
     25  public:
     26   ScopedPipe() : pipefd_{-1, -1} {
     27     int ret = pipe2(pipefd_, O_CLOEXEC);
     28     if (ret < 0) {
     29       LOG_ALWAYS_FATAL("failed to open pipe");
     30     }
     31   }
     32   ~ScopedPipe() {
     33     Close();
     34   }
     35 
     36   ScopedPipe(ScopedPipe&& other) {
     37     SetReceiver(other.ReleaseReceiver());
     38     SetSender(other.ReleaseSender());
     39   }
     40 
     41   ScopedPipe& operator = (ScopedPipe&& other) {
     42     SetReceiver(other.ReleaseReceiver());
     43     SetSender(other.ReleaseSender());
     44     return *this;
     45   }
     46 
     47   void CloseReceiver() {
     48     close(ReleaseReceiver());
     49   }
     50 
     51   void CloseSender() {
     52     close(ReleaseSender());
     53   }
     54 
     55   void Close() {
     56     CloseReceiver();
     57     CloseSender();
     58   }
     59 
     60   int Receiver() { return pipefd_[0]; }
     61   int Sender() { return pipefd_[1]; }
     62 
     63   int ReleaseReceiver() {
     64     int ret = Receiver();
     65     SetReceiver(-1);
     66     return ret;
     67   }
     68 
     69   int ReleaseSender() {
     70     int ret = Sender();
     71     SetSender(-1);
     72     return ret;
     73   }
     74 
     75  private:
     76   void SetReceiver(int fd) { pipefd_[0] = fd; };
     77   void SetSender(int fd) { pipefd_[1] = fd; };
     78 
     79   int pipefd_[2];
     80 };
     81 #endif
     82