root / synthbench / bonnie++ / .svn / text-base / semaphore.cpp.svn-base @ 0:839f52ef7657
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#include "port.h" |
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#include "semaphore.h" |
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#include <unistd.h> |
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#include <stdlib.h> |
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|
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Semaphore::Semaphore(int semKey, int numSems, int val) |
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: m_semid(0) |
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, m_semflg(IPC_CREAT | 0666) |
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, m_semopen(false) |
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, m_semKey(semKey) |
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, m_numSems(numSems) |
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{
|
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m_arg.val = (0); |
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if(val) |
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{
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if(create(val)) |
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exit(1); |
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} |
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} |
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|
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int Semaphore::clear_sem() |
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{
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int semid; |
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// have num-sems set to 1 so that we remove regardless of how many |
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// semaphores were present. |
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if((semid = semget(m_semKey, 1, 0666)) == -1) |
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{
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perror("Can't get semaphore ID");
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return 1; |
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} |
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if(semctl(semid, 0, IPC_RMID, m_arg) == -1) |
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{
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perror("Can't get remove semaphore");
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return 1; |
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} |
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printf("Semaphore removed.\n");
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return 0; |
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} |
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|
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int Semaphore::create(int count) |
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{
|
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if((m_semid = semget(m_semKey, m_numSems, m_semflg)) == -1) |
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{
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perror("Can't get semaphore");
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return 1; |
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} |
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m_arg.val = count; |
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int i; |
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for(i = 0; i < m_numSems; ++i) |
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{
|
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if(semctl(m_semid, i, SETVAL, m_arg) == -1) |
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{
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perror("Can't set semaphore value");
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return 1; |
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} |
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} |
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m_semopen = true; |
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return 0; |
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} |
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|
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int Semaphore::get_semid() |
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{
|
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int semflg = 0666; |
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if ((m_semid = semget(m_semKey, m_numSems, semflg)) == -1) |
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{
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perror("Can't get semaphore ID");
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return 1; |
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} |
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m_semopen = true; |
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return 0; |
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} |
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|
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int Semaphore::decrement_and_wait(int nr_sem) |
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{
|
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if(!m_semopen) |
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return 0; |
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struct sembuf sops; |
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sops.sem_num = nr_sem; |
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sops.sem_op = -1; |
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sops.sem_flg = IPC_NOWAIT; |
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if(semop(m_semid, &sops, 1) == -1) |
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{
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perror("semop: semop failed.\n");
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return 1; |
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} |
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sops.sem_num = nr_sem; |
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sops.sem_op = 0; |
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sops.sem_flg = SEM_UNDO; |
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if(semop(m_semid, &sops, 1) == -1) |
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{
|
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perror("semop: semop failed.\n");
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return 1; |
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} |
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return 0; |
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} |
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|
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int Semaphore::get_mutex() |
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{
|
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if(!m_semopen) |
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return 0; |
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struct sembuf sops; |
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sops.sem_num = 0; |
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sops.sem_op = -1; |
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sops.sem_flg = SEM_UNDO; |
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if(semop(m_semid, &sops, 1) == -1) |
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{
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perror("semop: semop failed.\n");
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return 1; |
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} |
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return 0; |
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} |
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|
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int Semaphore::put_mutex() |
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{
|
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if(!m_semopen) |
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return 0; |
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struct sembuf sops; |
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sops.sem_num = 0; |
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sops.sem_op = 1; |
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sops.sem_flg = IPC_NOWAIT; |
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if(semop(m_semid, &sops, 1) == -1) |
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{
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perror("semop: semop failed.\n");
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return 1; |
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} |
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return 0; |
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} |