static void *
drain_func(void *argument)
{
_thread_arg *arg;
int *ret;
FILE *f;
char *line;
useconds_t sleep_time;
int len_copy_out;
int i;
arg = (_thread_arg *)argument;
f = arg->f;
sleep_time = arg->time;
if ((ret = (int *)malloc(sizeof(int))) == NULL)
HANDLE_ERROR("drain_thread: malloc");
*ret = 0;
if ((line = (char *)malloc(sizeof(char) * CBUF_CAPACITY)) == NULL)
HANDLE_ERROR("drain_thread: malloc line");
while (1) {
if (usleep(sleep_time) == -1)
HANDLE_ERROR("usleep");
if (sem_wait(&items) == -1)
HANDLE_ERROR("sem_wait items");
if (sem_wait(&sem) == -1)
HANDLE_ERROR("sem_wait");
if (!cbuf_data_is_available()) {
printf("drain thread: no new string in buffer\n");
if (sem_post(&sem) == -1)
HANDLE_ERROR("sem_post");
} else {
len_copy_out = cbuf_copy_out(line);
printf("drain thread: read [%s] from buffer (nread=%d)\n", line, len_copy_out);
if (sem_post(&sem) == -1)
HANDLE_ERROR("sem_post");
if (strcmp(line, "QUIT") == 0)
break;
fwrite(line, len_copy_out - 1, 1, f);
}
for (i = 0; i < len_copy_out; ++i)
if (sem_post(&spaces) == -1)
HANDLE_ERROR("sem_post sapces");
}
free(line);
return (void *)ret;
}
/*
* Drains the buffer and writes each line to output file until "QUIT" is read
*/
void *drain_buffer(void *p) {
FILE *out_fp; /* file pointer to output file */
size_t len = 32 * sizeof(char); /* length of temp_buff */
size_t read_ret; /* number of bytes copied out of the shared buffer */
char *temp_buff = (char*)malloc(len); /* temp buffer for reading from shared buffer */
int done = 0; /* int to signal the thread to stop */
int ret = 0; /* return code of the thread * (0 by default) */
/* try to open output file for writing */
if ((out_fp = fopen(env.out_name, "w")) == NULL) {
perror("fopen output");
ret = -1;
pthread_exit(&ret);
}
while (1) {
if (usleep(env.drain_sleep) < 0) {
perror("usleep drain_thread");
ret = -1;
break;
}
/* wait for mutex lock */
if (pthread_mutex_lock(&env.lock) != 0) {
perror("pthread_mutex_lock drain_thread");
ret = -1;
break;
}
/* wait on data_avail condition variable if there is no data available */
if (!cbuf_data_is_available()) {
if (pthread_cond_wait(&env.data_avail, &env.lock) != 0) {
perror("pthread_cond_wait drain_thread");
ret = -1;
break;
}
}
/* --------------------------CRITICAL SECTION-------------------------- */
/* read string out of shared buffer */
read_ret = cbuf_copy_out(temp_buff);
printf("drain thread: read [%s] from buffer (nread=%d)\n", temp_buff, (int)read_ret);
/* if drain thread reads "QUIT" break and exit */
if (strcmp(temp_buff, "QUIT") == 0) {
done = 1;
} else {
/* write from temp buffer to output file */
if (fwrite(temp_buff, strlen(temp_buff), 1, out_fp) <= 0) {
perror("fwrite");
ret = -1;
break;
}
}
/* --------------------------CRITICAL SECTION-------------------------- */
/* signal to thread waiting on space_avail condition variable */
if (pthread_cond_signal(&env.space_avail) != 0) {
perror("pthread_cond_signal drain_thread");
ret = -1;
break;
}
/* release mutex lock */
if (pthread_mutex_unlock(&env.lock) != 0) {
perror("pthread_mutex_unlock drain_thread");
ret = -1;
break;
}
if (done) {
break;
}
}
printf("drain thread: exiting\n");
fclose(out_fp);
pthread_exit(&ret);
}
