132 lines
2.9 KiB
C++
132 lines
2.9 KiB
C++
#ifndef _WIN32 /// Linux
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#include "SemaphoreWrapper.h"
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#include <fcntl.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/ipc.h>
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#include <sys/sem.h>
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#include "log.h"
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class ProcessSemaphore::impl
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{
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public:
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int id;
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int key;
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int status;
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bool created;
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};
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static void _do_clean_up_semaphore(int key,int id)
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{
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if(semctl(id,0,IPC_RMID,0)<0)
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{
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log("Failed to destroy process semaphore (call semctl failed on key: %d, id: %d)",key,id);
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}
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}
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ProcessSemaphore::ProcessSemaphore(int key,int action,int default_value) : _p(new impl)
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{
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if(_p)
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{
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_p->key=key;
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_p->status=0;
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switch(action)
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{
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case 0:
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_p->id=semget(key,1,0666);
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break;
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case 1:
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_p->id=semget(key,1,0666|IPC_CREAT|IPC_EXCL);
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break;
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}
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if(_p->id<0)
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{
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_p->status=0;
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}
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else
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{
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_p->status=1;
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if(action==1) /// Created semaphore needs to be initialized
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{
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if(semctl(_p->id,0,SETVAL,1)>=0)
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{
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_p->status=2;
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_p->created=true;
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}
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}
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else /// Got a created semaphore
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{
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_p->status=2;
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_p->created=false;
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}
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if(_p->status!=2) /// Semaphore does not reach ready level.
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{
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_do_clean_up_semaphore(key,_p->id);
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_p->status=0; /// Set status to empty(0)
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}
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}
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}
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}
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bool ProcessSemaphore::isReady() const
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{
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return _p&&_p->status==2;
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}
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int ProcessSemaphore::p()
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{
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struct sembuf b;
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b.sem_num=0;
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b.sem_op=-1;
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b.sem_flg=SEM_UNDO;
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if(semop(_p->id,&b,1)<0)
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{
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return -1;
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}
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else return 0;
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}
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int ProcessSemaphore::v()
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{
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struct sembuf b;
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b.sem_num=0;
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b.sem_op=1;
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b.sem_flg=SEM_UNDO;
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if(semop(_p->id,&b,1)<0)
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{
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return -1;
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}
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else return 0;
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}
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int ProcessSemaphore::wait()
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{
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return p();
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}
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int ProcessSemaphore::notify()
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{
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return v();
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}
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ProcessSemaphore::~ProcessSemaphore()
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{
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if(_p)
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{
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if(_p->created)
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{
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_do_clean_up_semaphore(_p->key,_p->id);
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}
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delete _p;
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}
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}
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#endif /// End of Linux.
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