opentracker – An open and free bittorrent tracker
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/* This software was written by Dirk Engling <erdgeist@erdgeist.org>
It is considered beerware. Prost. Skol. Cheers or whatever. */
/* System */
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
/* Libowfat */
#include "byte.h"
/* Opentracker */
#include "trackerlogic.h"
#include "ot_mutex.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];
/* Bucket Magic */
static int bucket_locklist[ OT_MAX_THREADS ];
static int bucket_locklist_count = 0;
static pthread_mutex_t bucket_mutex;
static pthread_cond_t bucket_being_unlocked;
static int bucket_check( int bucket ) {
/* C should come with auto-i ;) */
int i;
/* No more space to acquire lock to bucket -- should not happen */
if( bucket_locklist_count == OT_MAX_THREADS ) {
fprintf( stderr, "More lock requests than mutexes. Consult source code.\n" );
return -1;
}
/* See, if bucket is already locked */
for( i=0; i<bucket_locklist_count; ++i )
if( bucket_locklist[ i ] == bucket )
return -1;
return 0;
}
static void bucket_push( int bucket ) {
bucket_locklist[ bucket_locklist_count++ ] = bucket;
}
static void bucket_remove( int bucket ) {
int i = 0;
while( ( i < bucket_locklist_count ) && ( bucket_locklist[ i ] != bucket ) )
++i;
if( i == bucket_locklist_count ) {
fprintf( stderr, "Request to unlock bucket that was never lock. Consult source code.\n" );
return;
}
for( ; i < bucket_locklist_count - 1; ++i )
bucket_locklist[ i ] = bucket_locklist[ i + 1 ];
--bucket_locklist_count;
}
ot_vector *mutex_bucket_lock( int bucket ) {
pthread_mutex_lock( &bucket_mutex );
while( bucket_check( bucket ) )
pthread_cond_wait( &bucket_being_unlocked, &bucket_mutex );
bucket_push( bucket );
pthread_mutex_unlock( &bucket_mutex );
return all_torrents + bucket;
}
ot_vector *mutex_bucket_lock_by_hash( ot_hash *hash ) {
unsigned char *local_hash = hash[0];
int bucket = ( local_hash[0] << 2 ) | ( local_hash[1] >> 6 );
/* Can block */
mutex_bucket_lock( bucket );
return all_torrents + bucket;
}
void mutex_bucket_unlock( int bucket ) {
pthread_mutex_lock( &bucket_mutex );
bucket_remove( bucket );
pthread_cond_broadcast( &bucket_being_unlocked );
pthread_mutex_unlock( &bucket_mutex );
}
void mutex_bucket_unlock_by_hash( ot_hash *hash ) {
unsigned char *local_hash = hash[0];
int bucket = ( local_hash[0] << 2 ) | ( local_hash[1] >> 6 );
mutex_bucket_unlock( bucket );
}
/* TaskQueue Magic */
struct ot_task {
ot_taskid taskid;
ot_tasktype tasktype;
int64 socket;
int iovec_entries;
struct iovec *iovec;
struct ot_task *next;
};
static ot_taskid next_free_taskid = 1;
static struct ot_task *tasklist = NULL;
static pthread_mutex_t tasklist_mutex;
static pthread_cond_t tasklist_being_filled;
int mutex_workqueue_pushtask( int64 socket, ot_tasktype tasktype ) {
struct ot_task ** tmptask, * task;
/* Want exclusive access to tasklist */
MTX_DBG( "pushtask locks.\n" );
pthread_mutex_lock( &tasklist_mutex );
MTX_DBG( "pushtask locked.\n" );
task = malloc(sizeof( struct ot_task));
if( !task ) {
MTX_DBG( "pushtask fail unlocks.\n" );
pthread_mutex_unlock( &tasklist_mutex );
MTX_DBG( "pushtask fail unlocked.\n" );
return -1;
}
/* Skip to end of list */
tmptask = &tasklist;
while( *tmptask )
tmptask = &(*tmptask)->next;
*tmptask = task;
task->taskid = 0;
task->tasktype = tasktype;
task->socket = socket;
task->iovec_entries = 0;
task->iovec = NULL;
task->next = 0;
/* Inform waiting workers and release lock */
MTX_DBG( "pushtask broadcasts.\n" );
pthread_cond_broadcast( &tasklist_being_filled );
MTX_DBG( "pushtask broadcasted, mutex unlocks.\n" );
pthread_mutex_unlock( &tasklist_mutex );
MTX_DBG( "pushtask end mutex unlocked.\n" );
return 0;
}
void mutex_workqueue_canceltask( int64 socket ) {
struct ot_task ** task;
/* Want exclusive access to tasklist */
MTX_DBG( "canceltask locks.\n" );
pthread_mutex_lock( &tasklist_mutex );
MTX_DBG( "canceltask locked.\n" );
task = &tasklist;
while( *task && ( (*task)->socket != socket ) )
*task = (*task)->next;
if( *task && ( (*task)->socket == socket ) ) {
struct iovec *iovec = (*task)->iovec;
struct ot_task *ptask = *task;
int i;
/* Free task's iovec */
for( i=0; i<(*task)->iovec_entries; ++i )
munmap( iovec[i].iov_base , iovec[i].iov_len );
*task = (*task)->next;
free( ptask );
}
/* Release lock */
MTX_DBG( "canceltask unlocks.\n" );
pthread_mutex_unlock( &tasklist_mutex );
MTX_DBG( "canceltask unlocked.\n" );
}
ot_taskid mutex_workqueue_poptask( ot_tasktype tasktype ) {
struct ot_task * task;
ot_taskid taskid = 0;
/* Want exclusive access to tasklist */
MTX_DBG( "poptask mutex locks.\n" );
pthread_mutex_lock( &tasklist_mutex );
MTX_DBG( "poptask mutex locked.\n" );
while( !taskid ) {
/* Skip to the first unassigned task this worker wants to do */
task = tasklist;
while( task && ( task->tasktype != tasktype ) && ( task->taskid ) )
task = task->next;
/* If we found an outstanding task, assign a taskid to it
and leave the loop */
if( task ) {
task->taskid = taskid = ++next_free_taskid;
} else {
/* Wait until the next task is being fed */
MTX_DBG( "poptask cond waits.\n" );
pthread_cond_wait( &tasklist_being_filled, &tasklist_mutex );
MTX_DBG( "poptask cond waited.\n" );
}
}
/* Release lock */
MTX_DBG( "poptask end mutex unlocks.\n" );
pthread_mutex_unlock( &tasklist_mutex );
MTX_DBG( "poptask end mutex unlocked.\n" );
return taskid;
}
int mutex_workqueue_pushresult( ot_taskid taskid, int iovec_entries, struct iovec *iovec ) {
struct ot_task * task;
/* Want exclusive access to tasklist */
MTX_DBG( "pushresult locks.\n" );
pthread_mutex_lock( &tasklist_mutex );
MTX_DBG( "pushresult locked.\n" );
task = tasklist;
while( task && ( task->taskid != taskid ) )
task = task->next;
if( task ) {
task->iovec_entries = iovec_entries;
task->iovec = iovec;
task->tasktype = OT_TASKTYPE_DONE;
}
/* Release lock */
MTX_DBG( "pushresult unlocks.\n" );
pthread_mutex_unlock( &tasklist_mutex );
MTX_DBG( "pushresult unlocked.\n" );
/* Indicate whether the worker has to throw away results */
return task ? 0 : -1;
}
int64 mutex_workqueue_popresult( int *iovec_entries, struct iovec ** iovec ) {
struct ot_task ** task;
int64 socket = -1;
/* Want exclusive access to tasklist */
MTX_DBG( "popresult locks.\n" );
pthread_mutex_lock( &tasklist_mutex );
MTX_DBG( "popresult locked.\n" );
task = &tasklist;
while( *task && ( (*task)->tasktype != OT_TASKTYPE_DONE ) )
task = &(*task)->next;
if( *task && ( (*task)->tasktype == OT_TASKTYPE_DONE ) ) {
struct ot_task *ptask = *task;
*iovec_entries = (*task)->iovec_entries;
*iovec = (*task)->iovec;
socket = (*task)->socket;
*task = (*task)->next;
free( ptask );
}
/* Release lock */
MTX_DBG( "popresult unlocks.\n" );
pthread_mutex_unlock( &tasklist_mutex );
MTX_DBG( "popresult unlocked.\n" );
return socket;
}
void mutex_init( ) {
pthread_mutex_init(&tasklist_mutex, NULL);
pthread_cond_init (&tasklist_being_filled, NULL);
pthread_mutex_init(&bucket_mutex, NULL);
pthread_cond_init (&bucket_being_unlocked, NULL);
byte_zero( all_torrents, sizeof( all_torrents ) );
}
void mutex_deinit( ) {
pthread_mutex_destroy(&bucket_mutex);
pthread_cond_destroy(&bucket_being_unlocked);
pthread_mutex_destroy(&tasklist_mutex);
pthread_cond_destroy(&tasklist_being_filled);
byte_zero( all_torrents, sizeof( all_torrents ) );
}