10 int ret = semget(IPC_PRIVATE, 1, IPC_CREAT | 0666);
11 return ret < 0? -E_SEM_GET : ret;
14 int mutex_remove(int id)
16 int ret = semctl(id, 0, IPC_RMID);
17 return ret < 0? -E_SEM_REMOVE : 1;
20 static void para_semop(int id, struct sembuf *sops, int num)
22 if (semop(id, sops, num) >= 0)
24 PARA_WARNING_LOG("semop failed (%s), retrying\n", strerror(errno));
25 while (semop(id, sops, num) < 0)
30 * lock the given mutex
32 * \sa semop(2), struct misc_meta_data
34 void mutex_lock(int id)
36 struct sembuf sops[2] = {
48 para_semop(id, sops, 2);
54 * \sa semop(2), struct misc_meta_data
56 void mutex_unlock(int id)
58 struct sembuf sops[1] = {
65 para_semop(id, sops, 1);
69 * create a new shared memory area of given size
73 int shm_new(size_t size)
75 int ret = shmget(IPC_PRIVATE, size, IPC_CREAT | IPC_EXCL | 0600);
76 return ret < 0 ? -E_SHM_GET : ret;
80 * destroy the given shared memory area
83 int shm_destroy(int id)
85 struct shmid_ds shm_desc;
86 int ret = shmctl(id, IPC_RMID, &shm_desc);
87 return ret < 0? -E_SHM_DESTROY : ret;
91 * attach a shared memory area
95 void *shm_attach(int id, enum shm_attach_mode mode)
97 if (mode == ATTACH_RW)
98 return shmat(id, NULL, 0);
99 return shmat(id, NULL, SHM_RDONLY);
101 int shm_detach(void *addr)
103 int ret = shmdt(addr);
104 return ret < 0? -E_SHM_DETACH : 1;