66 lines
1.2 KiB
C++
66 lines
1.2 KiB
C++
#ifndef _GUARDER_H
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#define _GUARDER_H
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#include <sys/types.h>
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#include <sys/shm.h>
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#include <sys/ipc.h>
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#include <sys/sem.h>
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#include <unistd.h>
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class guarder{
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private:
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const int shmid;
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const int semid;
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void semaphoreOp(int op) {
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struct sembuf sb{};
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sb.sem_num = 0;
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sb.sem_op = op;
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sb.sem_flg = 0;
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semop(semid, &sb, 1);
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}
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void setFlag(bool value)
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{
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semaphoreOp(-1);
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bool *flag = static_cast<bool *>(shmat(shmid, nullptr, 0));
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*flag = value;
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shmdt(flag);
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semaphoreOp(1);
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}
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public:
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guarder() : shmid(shmget(IPC_PRIVATE, sizeof(bool), 0666 | IPC_CREAT)), semid(semget(IPC_PRIVATE, 1, 0666 | IPC_CREAT))
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{
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setFlagOff();
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}
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void setFlagOff()
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{
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setFlag(false);
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}
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void setFlagOn()
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{
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setFlag(true);
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}
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bool isFlagOn()
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{
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semaphoreOp(-1);
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bool *flag = static_cast<bool *>(shmat(shmid, nullptr, 0));
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bool ret = *flag;
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shmdt(flag);
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semaphoreOp(1);
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return ret;
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}
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~guarder()
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{
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shmctl(shmid, IPC_RMID, nullptr);
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semctl(semid, 0, IPC_RMID);
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}
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};
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#endif // _GUARDER_H
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