/* Se invoca al hacer read() de entrada /proc */
static ssize_t fifo_read(struct file *file, char __user *buf, size_t len, loff_t *off){
char kbuffer[MAX_CBUFFER_LEN];
if (len> MAX_CBUFFER_LEN) {
return -EFAULT;
}
if (down_interruptible(&mtx)){
return -EINTR;
}
while (size_cbuffer_t(cbuffer)<len && prod_count>0){
nr_cons_waiting +=1;
up(&mtx);
if (down_interruptible(&sem_cons)){
return -EINTR;
}
}
if(prod_count == 0 && size_cbuffer_t(cbuffer) == 0){
up(&mtx);
return 0;
}
remove_items_cbuffer_t(cbuffer,kbuffer,len);
if(nr_prod_waiting > 0){
up(&sem_prod);
nr_prod_waiting -=1;
}
up(&mtx);
if (copy_to_user(buf,kbuffer,len)) {
return -EFAULT;
}
return len;
}
int remove_cbuffer_t_batch(cbuffer_t* cbuffer, char* items, int max_nr_items)
{
/* Check the maximum number of bytes we can actually retrieve */
int nr_items=max_nr_items>cbuffer->size?cbuffer->size:max_nr_items;
/* Remove items from the buffer!! */
if (nr_items)
remove_items_cbuffer_t (cbuffer, items, nr_items);
return nr_items;
}
int fifoproc_read(const char* buff, int len) {
char kbuffer[MAX_KBUF];
if(len > MAX_CBUFFER_LEN || len>MAX_KBUF) { return Error;}
lock(mtx);
/*Esperar hasta que haya elementos que leer*/
while(size_cbuffer_t(cbuffer)==0 && prod_count>0) {
cond_wait(cons,mtx);
}
/*En caso de no existir productores finaliza con EOF*/
if ((prod_count==0)&&(size_cbuffer_t(cbuffer)==0)) {unlock(mtx); return 0;}
/*Elimina los elementos leidos del buffer y manda una señal a los productores
*por si alguno dormido*/
remove_items_cbuffer_t(cbuffer, kbuffer, len);
cond_signal(prod);
unlock(mtx);
copy_to_user(buff, kbuffer, strlen(kbuffer));
return strlen(kbuffer);
}
