static int lock_sem(int sid)
{
int member = 0;
struct sembuf sem_lock={ 0, -1, IPC_NOWAIT};
int success = 0;
//printf("locking sem, member count = %d\n", get_sem_member_count(sid) );
/* Attempt to lock the semaphore set */
int semval = get_sem_val(sid, member);
if(semval > 0)
{
sem_lock.sem_num = member;
if((semop(sid, &sem_lock, 1)) != -1)
{
success = 1;
}
}
return success;
}
static int unlock_sem(int sid)
{
int member = 0;
struct sembuf sem_unlock={ member, 1, IPC_NOWAIT};
/* will fail if we can't can't unlock semaphore for some reason,
* will NOT fail if semaphore is already unlocked
*/
int success = 1;
/* Is the semaphore set locked? */
int semval = get_sem_val(sid, member);
if(semval == 0)
{
/* it's locked, unlock it */
sem_unlock.sem_num = member;
success = ((semop(sid, &sem_unlock, 1)) == -1) ? 0 : 1;
}
return success;
}
int main(int argc, char ** argv){
key_t key;
int *shm_seg, shm_id, sem_id, pid, fd_fifo;
int i, tmp, count_r;
int r_arr[2];
unsigned int nn, n, size;
struct sigaction sa;
memset(&sa, 0, sizeof(sa));
sa.sa_handler = sigchldhandler;
if (sigaction(SIGCHLD, &sa, 0) < 0){
perror("sigaction");
exit(0);
}
printf("n: "); scanf("%u", &n);
if (n < 2){ printf("n must be bigger than 1\n"); exit(0); }
nn = 2;
while (nn < n){
nn <<= 1;
}
/*-initialize*/
if (mknod(FIFO, S_IFIFO | 0660, 0) < 0){ perror("mknod: "); exit(2); }
if ((key = ftok(argv[0], 'q')) < 0) { perror("ftok"); exit(2); }/*========================================================================*/
size = nn*sizeof(int);
if ((shm_id = open_seg(key,size)) < 0){ printf("open_seg error\n"); exit(2); }
if (*(shm_seg = shmat(shm_id, 0, 0)) < 0) { printf("error attaching %d\n",shm_id); exit(2); }
if ((sem_id = open_sem(key,4)) < 0){ printf("open_sem error\n"); exit(2); }
srand(key);
for(i = 0; i < n; i++){
shm_seg[i] = rand() % 100;
printf("%d ", shm_seg[i]);
}
for(; i < nn; i++){
shm_seg[i] = 100;
printf("%d ", 100);
}
printf("\n");
/*=initialize*/
op_sem(sem_id, &r_unlock[0]);
op_sem(sem_id, &w_unlock[0]);
for(i = 0; i < nn/2; i++){
if ((pid = fork()) < 0){ printf("fork %d", i); exit(0); }
if (pid == 0){
if ((fd_fifo = open(FIFO, O_RDONLY | O_NONBLOCK)) < 0){
if (errno == EINTR){
_exit(0);
}
perror("open2: ");
_exit(2);
}
while (get_sem_val(sem_id, 3) > 0){
r_arr[0] = 0; r_arr[1] = 0;
/*
trouble: В конце работы read читает из пустой фифо. Надо найти макс задержку read'а. Или семафоры...:(
*/
op_sem(sem_id, &r_lock[0]);
if ((count_r = read(fd_fifo, &r_arr, sizeof(int)*2)) < 0){
if (errno == EAGAIN){
continue;
}
perror("read: ");
_exit(2);
};
if (count_r < 2){ continue; }
op_sem(sem_id, &iter_unlock[0]);
op_sem(sem_id, &r_unlock[0]);
if (shm_seg[r_arr[0]] > shm_seg[r_arr[1]]){
tmp = shm_seg[r_arr[0]];
op_sem(sem_id, &w_lock[0]);
shm_seg[r_arr[0]] = shm_seg[r_arr[1]];
shm_seg[r_arr[1]] = tmp;
op_sem(sem_id, &w_unlock[0]);
}
}
printf("die.\n");
if (close(fd_fifo) < 0){
perror("close2");
}
_exit(0);
}
}
while (1){
if ((fd_fifo = open(FIFO, O_WRONLY | O_NONBLOCK)) < 0){
if (errno == EINTR || errno == ENXIO){
continue;
}
perror("open3: ");
exit(0);
}else{
break;
}
}
op_sem(sem_id, &work_start[0]);
make_mn(nn, nn, 1, fd_fifo, sem_id);
op_sem(sem_id, &work_stop[0]);
if (close(fd_fifo) < 0){
perror("close2");
};
for(i = 0; i < n; i++){
printf("%d ", shm_seg[i]);
}
printf("\n");
while(die < nn/2);
detach_seg((char *)shm_seg);
close_seg(shm_id);
close_sem(sem_id);
return 0;
}
