t_cached_object *search_cache(t_session *session, char *file) {
off_t size;
if(file == NULL) {
return NULL;
} else if((size = filesize(file)) == -1) {
return NULL;
}
int i;
if((i = cache_index(file)) == -1) {
return NULL;
}
pthread_mutex_lock(&cache_mutex[i]);
t_cached_object *object = cache[i], *result = NULL;
struct stat status;
/*object = cache[i];*/
while(object != NULL) {
if(object->size == size) {
if (strcmp(object->file, file) == 0) {
if(stat(file, &status) == 0) {
if((object->deadline > session->time) && (status.st_mtime == object->last_changed)) {
if(same_ip(&(object->last_ip), &(session->ip_address)) == false) {
if((object->deadline += TIME_IN_CACHE) > (session->time + MAX_CACHE_TIMER)) {
object->deadline = session->time + MAX_CACHE_TIMER;
}
copy_ip(&(object->last_ip), &(session->ip_address));
}
object->in_use++;
result = object;
} else if(object->in_use <= 0) {
remove_from_cache(object, i);
}
} else if(object->in_use <= 0) {
remove_from_cache(object, i);
}
break;
}
}
object = object->next;
}
pthread_mutex_unlock(&cache_mutex[i]);
return result;
}
int add_to_cache(char * data, int site_size, char* uri) {
if (site_size + sizeof(cache_object) <= MAX_OBJECT_SIZE)
{
return 0;
} else {
dbg_printf("add_to_cache");
/* Writing to the cache - only one thread should be able to write to it */
pthread_rwlock_wrlock(&lock); /* lock on the resource*/
/* Free enough space for the new site in cache*/
while(cache_size + site_size + sizeof(cache_object) >= MAX_CACHE_SIZE ){
remove_from_cache();
}
/* Add the site node to the start of the cache list*/
cache_object * site = (cache_object *)malloc(sizeof(cache_object));
site -> next = head;
site -> data = data;
site -> lru_time_track = global_time++;
site -> size = site_size;
site -> uri = malloc(( strlen( uri ) + 1 ) * sizeof( char ));
strcpy( site -> uri, uri );
head = site;
cache_size += sizeof( cache_object ) + site_size +
strlen( uri ) + 1;
pthread_rwlock_unlock( &lock );
return 1;
}
}
static void remove_output_from_cache(t_session *session, char *request_uri, t_cot_type cot_type) {
t_cached_object *object;
char *url;
int index;
if ((url = make_url(session, request_uri)) == NULL) {
return;
} else if ((index = cache_index(url)) == -1) {
free(url);
return;
}
pthread_mutex_lock(&cache_mutex[index]);
object = cache[index];
while (object != NULL) {
if (object->type == cot_type) {
if (strcmp(object->file, url) == 0) {
if (object->in_use <= 0) {
remove_from_cache(object, index);
} else {
object->deadline = 0;
}
break;
}
}
object = object->next;
}
pthread_mutex_unlock(&cache_mutex[index]);
free(url);
}
static void flush_output_cache(t_session *session, t_cot_type cot_type) {
t_cached_object *object;
int index;
size_t len;
for (index = 0; index < MAX_CACHE_INDEX; index++) {
pthread_mutex_lock(&cache_mutex[index]);
object = cache[index];
while (object != NULL) {
if (object->type == cot_type) {
len = strlen(*(session->host->hostname.item));
if (strncmp(object->file, *(session->host->hostname.item), len) == 0) {
if (*(object->file + len) == '/') {
if (object->in_use <= 0) {
object = remove_from_cache(object, index);
continue;
} else {
object->deadline = 0;
}
}
}
}
object = object->next;
}
pthread_mutex_unlock(&cache_mutex[index]);
}
}
void insert_into_cache(struct cache_header *cache, size_t size, char* data, char* tag){
pthread_rwlock_wrlock(&lock);
struct cache_block *new_block = malloc(sizeof(struct cache_block));
if (cache->total_size + size > MAX_CACHE_SIZE) remove_from_cache(cache,size);
new_block->next = cache->start;
cache->start = new_block;
cache->total_size += size;
new_block->size = size;
new_block->data = malloc(size);
memcpy(new_block->data, data, size);
new_block->tag = malloc(strlen(tag) + 1);
strcpy(new_block->tag,tag);
new_block->timestamp = ++cache->currTime;
Sem_init(&new_block->mutex, 0, 1);
pthread_rwlock_unlock(&lock);
}
void manage_cache(time_t now) {
t_cached_object *object;
int index;
for (index = 0; index < MAX_CACHE_INDEX; index++) {
pthread_mutex_lock(&cache_mutex[index]);
object = cache[index];
while (object != NULL) {
if (now > object->deadline) {
if (object->in_use <= 0) {
object = remove_from_cache(object, index);
continue;
}
}
object = object->next;
}
pthread_mutex_unlock(&cache_mutex[index]);
}
}
static int swap_out(frame_t victim) {
printf("%s: Swap Out Page %5d, Frame %5d\n", current_ref,
physical_mem[victim].page_ref->page,
victim);
/*
* Pull from Cache
*/
remove_from_cache(physical_mem[victim].page_ref->pid, physical_mem[victim].page_ref->page);
/*
* Pull from TLB
*/
remove_from_tlb(physical_mem[victim].page_ref->page, physical_mem[victim].page_ref->pid);
/*
* Simulate time to write out to disk (only if page is dirty)
*/
if( physical_mem[victim].dirty ) {
nanosleep(&ACCESS_TIME_DISK, NULL);
stats.swap_out++;
}
/*
* Update the page table of the victim
*/
physical_mem[victim].page_ref->frame = 0;
physical_mem[victim].page_ref->valid = false;
physical_mem[victim].page_ref = NULL;
/*
* Add frame to the free frame list
*/
next_free_frame++;
free_frame_list[next_free_frame] = victim;
return 0;
}
void check_cache(time_t now) {
t_cached_object *object;
int i;
for(i = 0; i < MAX_CACHE_INDEX; i++) {
pthread_mutex_lock(&cache_mutex[i]);
object = cache[i];
while(object != NULL) {
if(now > object->deadline) {
if(object->in_use <= 0) {
object = remove_from_cache(object, i);
continue;
} else {
object->deadline = 0;
}
}
object = object->next;
}
pthread_mutex_unlock(&cache_mutex[i]);
}
}
static t_cached_object *search_cache_for_output(t_session *session, t_cot_type cot_type) {
t_cached_object *object, *result = NULL;
char *url;
int index;
if ((url = make_url(session, NULL)) == NULL) {
return NULL;
} else if ((index = cache_index(url)) == -1) {
free(url);
return NULL;
}
pthread_mutex_lock(&cache_mutex[index]);
object = cache[index];
while (object != NULL) {
if (object->type == cot_type) {
if (strcmp(object->file, url) == 0) {
if (object->deadline > session->time) {
object->in_use++;
result = object;
} else if (object->in_use <= 0) {
remove_from_cache(object, index);
}
break;
}
}
object = object->next;
}
pthread_mutex_unlock(&cache_mutex[index]);
free(url);
return result;
}
