xwords/xwords4/relay/tpool.cpp

/* -*- compile-command: "make -j3"; -*- */

/* 
 * Copyright 2005 - 2012 by Eric House (xwords@eehouse.org).  All rights
 * reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

#include <assert.h>
#include <stdio.h>
#include <unistd.h>
#include <pthread.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/poll.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>

#include "tpool.h"
#include "xwrelay_priv.h"
#include "xwrelay.h"
#include "timermgr.h"
#include "mlock.h"

XWThreadPool* XWThreadPool::g_instance = NULL;

/* static */ XWThreadPool*
XWThreadPool::GetTPool()
{
    XWThreadPool* me = g_instance;
    if ( me == NULL ) {
        me = new XWThreadPool();
        g_instance = me;
    }
    return me;
}

XWThreadPool::XWThreadPool()
    : m_timeToDie(false)
    , m_nThreads(0)
{
    pthread_rwlock_init( &m_activeSocketsRWLock, NULL );
    pthread_mutex_init ( &m_queueMutex, NULL );

    pthread_cond_init( &m_queueCondVar, NULL );

    int fd[2];
    if ( pipe( fd ) ) {
        logf( XW_LOGERROR, "pipe failed" );
    }
    m_pipeRead = fd[0];
    m_pipeWrite = fd[1];
    logf( XW_LOGINFO, "pipes: m_pipeRead: %d; m_pipeWrite: %d",
          m_pipeRead, m_pipeWrite );
}

XWThreadPool::~XWThreadPool()
{
    pthread_cond_destroy( &m_queueCondVar );

    pthread_rwlock_destroy( &m_activeSocketsRWLock );
    pthread_mutex_destroy ( &m_queueMutex );
} /* ~XWThreadPool */

void
XWThreadPool::Setup( int nThreads, kill_func kFunc )
{
    m_nThreads = nThreads;
    m_threadInfos = (ThreadInfo*)malloc( nThreads * sizeof(*m_threadInfos) );
    m_kFunc = kFunc;

    for ( int ii = 0; ii < nThreads; ++ii ) {
        ThreadInfo* tip = &m_threadInfos[ii];
        tip->me = this;
        int result = pthread_create( &tip->thread, NULL, tpool_main, tip );
        assert( result == 0 );
        pthread_detach( tip->thread );
    }

    pthread_t thread;
    int result = pthread_create( &thread, NULL, listener_main, this );
    assert( result == 0 );
    result = pthread_detach( thread );
    assert( result == 0 );
}

void
XWThreadPool::Stop()
{
    m_timeToDie = true;

    int ii;
    for ( ii = 0; ii < m_nThreads; ++ii ) {
        SockInfo si;
        si.m_type = STYPE_UNKNOWN;
        enqueue( si );
    }

    interrupt_poll();
}

void
XWThreadPool::AddSocket( SockType stype, QueueCallback proc, const AddrInfo* from )
{
    {
        RWWriteLock ml( &m_activeSocketsRWLock );
        SockInfo si;
        si.m_type = stype;
        si.m_proc = proc;
        si.m_addr = *from;
        m_activeSockets.push_back( si );
        logf( XW_LOGINFO, "%s: %d sockets active", __func__, 
              m_activeSockets.size() );
    }
    interrupt_poll();
}

bool
XWThreadPool::RemoveSocket( const AddrInfo* addr )
{
    assert( addr->isTCP() );
    bool found = false;
    {
        RWWriteLock ml( &m_activeSocketsRWLock );

        logf( XW_LOGINFO, "%s: START: %d sockets active", __func__, 
              m_activeSockets.size() );

        vector<SockInfo>::iterator iter;
        for ( iter = m_activeSockets.begin(); 
              iter != m_activeSockets.end(); ++iter ) {
            if ( iter->m_addr.equals( *addr ) ) {
                m_activeSockets.erase( iter );
                found = true;
                break;
            }
        }
        logf( XW_LOGINFO, "%s: AFTER: %d sockets active", __func__, 
              m_activeSockets.size() );
    }
    return found;
} /* RemoveSocket */

void
XWThreadPool::CloseSocket( const AddrInfo* addr )
{
/*     bool do_interrupt = false; */
    assert( addr->isTCP() );
    if ( !RemoveSocket( addr ) ) {
        MutexLock ml( &m_queueMutex );
        deque<QueuePr>::iterator iter = m_queue.begin();
        while ( iter != m_queue.end() ) {
            if ( iter->m_info.m_addr.equals( *addr ) ) {
                m_queue.erase( iter );
/*                 do_interrupt = true; */
                break;
            }
            ++iter;
        }
    }
    logf( XW_LOGINFO, "CLOSING socket %d", addr->socket() );
    close( addr->socket() );
/*     if ( do_interrupt ) { */
    /* We always need to interrupt the poll because the socket we're closing
       will be in the list being listened to.  That or we need to drop sockets
       that have been removed on some other thread while the poll call's
       blocking.*/
    interrupt_poll();
/*     } */
}

void
XWThreadPool::EnqueueKill( const AddrInfo* addr, const char* const why )
{
    logf( XW_LOGINFO, "%s(%d) reason: %s", __func__, addr->socket(), why );
    if ( addr->isTCP() ) {
        SockInfo si;
        si.m_type = STYPE_UNKNOWN;
        si.m_addr = *addr;
        enqueue( si, Q_KILL );
    }
}

bool
XWThreadPool::get_process_packet( SockType stype, QueueCallback proc, const AddrInfo* addr )
{
    bool success = false;
    short packetSize;
    assert( sizeof(packetSize) == 2 );

    // Fix this to return an allocated buffer
    unsigned char buf[MAX_MSG_LEN+1];
    int nRead = read_packet( addr->socket(), buf, sizeof(buf) );
    if ( nRead < 0 ) {
        EnqueueKill( addr, "bad packet" );
    } else if ( STYPE_PROXY == stype && NULL != proc ) {
        buf[nRead] = '\0';
        UdpQueue::get()->handle( addr, buf, nRead+1, proc );
    } else if ( STYPE_GAME == stype && NULL != proc ) {
        UdpQueue::get()->handle( addr, buf, nRead, proc );
        success = true;
    } else {
        assert(0);
    }
    return success;
} /* get_process_packet */

void*
XWThreadPool::tpool_main( void* closure )
{
    blockSignals();

    ThreadInfo* tip = (ThreadInfo*)closure;
    return tip->me->real_tpool_main( tip );
}

void*
XWThreadPool::real_tpool_main( ThreadInfo* tip )
{
    logf( XW_LOGINFO, "tpool worker thread starting" );
    int socket = -1;
    for ( ; ; ) {
        pthread_mutex_lock( &m_queueMutex );
        tip->recentTime = 0;

        release_socket_locked( socket );

        while ( !m_timeToDie && m_queue.size() == 0 ) {
            pthread_cond_wait( &m_queueCondVar, &m_queueMutex );
        }

        if ( m_timeToDie ) {
            logf( XW_LOGINFO, "%s: unlocking b/c m_timeToDie set", __func__ );
            pthread_mutex_unlock( &m_queueMutex );
            break;
        }

        QueuePr pr;
        bool gotOne = grab_elem_locked( &pr );

        tip->recentTime = time( NULL );
        pthread_mutex_unlock( &m_queueMutex );

        if ( gotOne ) {
            socket = pr.m_info.m_addr.socket();
            logf( XW_LOGINFO, "worker thread got socket %d from queue", socket );
            switch ( pr.m_act ) {
            case Q_READ:
                assert( socket >= 0 );
                if ( get_process_packet( pr.m_info.m_type, pr.m_info.m_proc, &pr.m_info.m_addr ) ) {
                    AddSocket( pr.m_info.m_type, pr.m_info.m_proc, &pr.m_info.m_addr );
                }
                break;
            case Q_KILL:
                (*m_kFunc)( &pr.m_info.m_addr );
                CloseSocket( &pr.m_info.m_addr );
                break;
            }
        } else {
            socket = -1;
        }
    }
    logf( XW_LOGINFO, "tpool worker thread exiting" );
    return NULL;
}

void
XWThreadPool::interrupt_poll()
{
#ifdef LOG_POLL
    logf( XW_LOGINFO, __func__ );
#endif
    unsigned char byt = 0;
    int nSent = write( m_pipeWrite, &byt, 1 );
    if ( nSent != 1 ) {
        logf( XW_LOGERROR, "errno = %s (%d)", strerror(errno), errno );
    }
}

void*
XWThreadPool::real_listener()
{
    int flags = POLLIN | POLLERR | POLLHUP | POLLRDHUP;
    TimerMgr* tmgr = TimerMgr::GetTimerMgr();
    int nSocketsAllocd = 1;

    struct pollfd* fds = (pollfd*)calloc( nSocketsAllocd, sizeof(fds[0]) );
    SockInfo* sinfos = (SockInfo*)calloc( nSocketsAllocd, sizeof(sinfos[0]) );
#ifdef LOG_POLL
    char* log = (char*)malloc( 4 * nSocketsAllocd );
#endif

    for ( ; ; ) {

        pthread_rwlock_rdlock( &m_activeSocketsRWLock );
        int nSockets = m_activeSockets.size() + 1; /* for pipe */
#ifdef LOG_POLL
        int logCapacity = 4 * nSockets;
        int logLen = 0;
#endif

        if ( nSockets > nSocketsAllocd ) {
            fds = (struct pollfd*)realloc( fds, nSockets * sizeof(fds[0]) );
            sinfos = (SockInfo*)realloc( sinfos, nSockets * sizeof(sinfos[0]) );
#ifdef LOG_POLL
            log = (char*)realloc( log, nSockets * 4 );
#endif
            nSocketsAllocd = nSockets;
        }
        int curfd = 0;
        
        fds[curfd].fd = m_pipeRead;
        fds[curfd].events = flags;
#ifdef LOG_POLL
        logLen += snprintf( log+logLen, logCapacity - logLen, "%d,", 
                            fds[curfd].fd );
#endif
        ++curfd;

        vector<SockInfo>::iterator iter;
        for ( iter = m_activeSockets.begin(); iter != m_activeSockets.end(); 
              ++iter ) {
            fds[curfd].fd = iter->m_addr.socket();
            sinfos[curfd] = *iter;
            fds[curfd].events = flags;
#ifdef LOG_POLL
            if ( logCapacity > logLen ) {
                logLen += snprintf( log+logLen, logCapacity - logLen, "%d,", 
                                    fds[curfd].fd );
            }
#endif
            assert( curfd < nSockets );
            ++curfd;
        }
        pthread_rwlock_unlock( &m_activeSocketsRWLock );

        int nMillis = tmgr->GetPollTimeoutMillis();

#ifdef LOG_POLL
        logf( XW_LOGINFO, "polling %s nmillis=%d", log, nMillis );
#endif
        int nEvents = poll( fds, nSockets, nMillis );
#ifdef LOG_POLL
        logf( XW_LOGINFO, "back from poll: %d", nEvents );
#endif
        if ( m_timeToDie ) {
            break;
        }

        if ( nEvents == 0 ) {
            tmgr->FireElapsedTimers();
        } else if ( nEvents < 0 ) {
            logf( XW_LOGERROR, "poll failed: errno: %s (%d)", 
                  strerror(errno), errno );
        } 

        if ( fds[0].revents != 0 ) {
#ifdef LOG_POLL
            logf( XW_LOGINFO, "poll interrupted" );
#endif
            assert( fds[0].revents == POLLIN );
            unsigned char byt;
            read( fds[0].fd, &byt, 1 );
            --nEvents;
        }

        if ( nEvents > 0 ) {
            --nSockets;
            curfd = 1;

            int ii;
            for ( ii = 0; ii < nSockets && nEvents > 0; ++ii ) {

                if ( fds[curfd].revents != 0 ) {
                    int socket = fds[curfd].fd;
                    const AddrInfo* addr = &sinfos[curfd].m_addr;
                    assert( socket == addr->socket() );
                    if ( !RemoveSocket( addr ) ) {
                        /* no further processing if it's been removed while
                           we've been sleeping in poll */
                        --nEvents;
                        continue;
                    }

                    if ( 0 != (fds[curfd].revents & (POLLIN | POLLPRI)) ) {
                        enqueue( sinfos[curfd] );
                    } else {
                        logf( XW_LOGERROR, "odd revents: %x", 
                              fds[curfd].revents );
                        EnqueueKill( addr, "error/hup in poll()" ); 
                    }
                    --nEvents;
                }
                ++curfd;
            }
            assert( nEvents == 0 );
        }
    }

    free( fds );
    free( sinfos );
#ifdef LOG_POLL
    free( log );
#endif

    logf( XW_LOGINFO, "real_listener returning" );
    return NULL;
} /* real_listener */

/* static */ void*
XWThreadPool::listener_main( void* closure )
{
    blockSignals();    

    XWThreadPool* me = (XWThreadPool*)closure;
    return me->real_listener();
}

void
XWThreadPool::enqueue( SockInfo si, QAction act ) 
{
    QueuePr pr = { act, si };
    MutexLock ml( &m_queueMutex );
    m_queue.push_back( pr );

    pthread_cond_signal( &m_queueCondVar );
    log_hung_threads();
}

bool
XWThreadPool::grab_elem_locked( QueuePr* prp )
{
    bool found = false;
    deque<QueuePr>::iterator iter;
    for ( iter = m_queue.begin(); !found && iter != m_queue.end(); ++iter ) {
        int socket = iter->m_info.m_addr.socket();
        /* If NOT found */
        if ( m_sockets_in_use.end() == m_sockets_in_use.find( socket ) ) {
            *prp = *iter;
            m_queue.erase( iter ); /* this was a double-free once! */
            m_sockets_in_use.insert( socket );
            found = true;
        }
    }

    print_in_use();
    return found;
} /* grab_elem_locked */

void
XWThreadPool::release_socket_locked( int socket )
{
    if ( -1 != socket ) {
        set<int>::iterator iter = m_sockets_in_use.find( socket );
        assert( iter != m_sockets_in_use.end() );
        m_sockets_in_use.erase( iter );
    }
    print_in_use();
}

void
XWThreadPool::print_in_use( void )
{
    string str;
    set<int>::iterator iter;

    for ( iter = m_sockets_in_use.begin(); 
          iter != m_sockets_in_use.end(); ++iter ) {
	string_printf( str, "%d ", *iter );
    }
    if ( 0 < str.size() ) {
	logf( XW_LOGINFO, "Sockets in use: %s", str.c_str() );
    }
}

// We have the mutex when this is called
void
XWThreadPool::log_hung_threads( void )
{
    const time_t HUNG_THREASHHOLD = 300; // seconds
    int ii;
    time_t now = time( NULL );
    for ( ii = 0; ii < m_nThreads; ++ii ) {
        ThreadInfo* tip = &m_threadInfos[ii];
        time_t recentTime = tip->recentTime;
        if ( 0 != recentTime ) {
            time_t howLong = now - recentTime;
            if ( HUNG_THREASHHOLD < howLong ) {
                logf( XW_LOGERROR, "thread %d (%p) stopped for %d seconds!",
                      ii, tip->thread, howLong );
                tip->recentTime = 0;   // only log once
                assert(0);
            }
        }
    }
}