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/* This software was written by Dirk Engling <erdgeist@erdgeist.org>
It is considered beerware. Prost. Skol. Cheers or whatever.
$id$ */
/* System */
#include <arpa/inet.h>
#include <pthread.h>
#include <stdatomic.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/uio.h>
/* Opentracker */
#include "ot_iovec.h"
#include "ot_mutex.h"
#include "ot_stats.h"
#include "trackerlogic.h"
/* #define MTX_DBG( STRING ) fprintf( stderr, STRING ) */
#define MTX_DBG(STRING)
/* Our global all torrents list */
static ot_vector all_torrents[OT_BUCKET_COUNT];
static pthread_mutex_t bucket_mutex[OT_BUCKET_COUNT];
/* Every bucket's unlock adjusts this, and a bucket lock only keeps other
threads out of that one bucket, so the counter needs its own protection */
static _Atomic size_t g_torrent_count;
/* Self pipe from opentracker.c */
ot_vector *mutex_bucket_lock(int bucket) {
pthread_mutex_lock(bucket_mutex + bucket);
return all_torrents + bucket;
}
/* Torrents are spread over buckets by the first four bytes of their info_hash,
which may sit at any alignment, hence the memcpy */
static int bucket_from_hash(ot_hash const hash) {
uint32_t bucket;
memcpy(&bucket, hash, sizeof(bucket));
return ntohl(bucket) >> OT_BUCKET_COUNT_SHIFT;
}
ot_vector *mutex_bucket_lock_by_hash(ot_hash const hash) { return mutex_bucket_lock(bucket_from_hash(hash)); }
void mutex_bucket_unlock(int bucket, int delta_torrentcount) {
pthread_mutex_unlock(bucket_mutex + bucket);
if (delta_torrentcount)
atomic_fetch_add_explicit(&g_torrent_count, (size_t)delta_torrentcount, memory_order_relaxed);
}
void mutex_bucket_unlock_by_hash(ot_hash const hash, int delta_torrentcount) {
mutex_bucket_unlock(bucket_from_hash(hash), delta_torrentcount);
}
size_t mutex_get_torrent_count(void) { return atomic_load_explicit(&g_torrent_count, memory_order_relaxed); }
void mutex_init(void) {
size_t i;
for (i = 0; i < OT_BUCKET_COUNT; ++i)
pthread_mutex_init(bucket_mutex + i, NULL);
memset(all_torrents, 0, sizeof(all_torrents));
}
/* Let every worker parked on the queue see that the tracker is stopping */
void mutex_deinit(void) {
size_t i;
for (i = 0; i < OT_BUCKET_COUNT; ++i)
pthread_mutex_destroy(bucket_mutex + i);
memset(all_torrents, 0, sizeof(all_torrents));
}
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