openmpi/ompi/mpi/c/comm_join.c

/*
 * Copyright (c) 2004-2007 The Trustees of Indiana University and Indiana
 *                         University Research and Technology
 *                         Corporation.  All rights reserved.
 * Copyright (c) 2004-2005 The University of Tennessee and The University
 *                         of Tennessee Research Foundation.  All rights
 *                         reserved.
 * Copyright (c) 2004-2005 High Performance Computing Center Stuttgart, 
 *                         University of Stuttgart.  All rights reserved.
 * Copyright (c) 2004-2005 The Regents of the University of California.
 *                         All rights reserved.
 * Copyright (c) 2012      Los Alamos National Security, LLC.
 *                         All rights reserved.
 * $COPYRIGHT$
 * 
 * Additional copyrights may follow
 * 
 * $HEADER$
 */
#include "ompi_config.h"
#include <stdio.h>
#include <string.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#include <errno.h>
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif

#include "ompi/mpi/c/bindings.h"
#include "ompi/runtime/params.h"
#include "ompi/communicator/communicator.h"
#include "ompi/errhandler/errhandler.h"
#include "ompi/mca/dpm/dpm.h"


#if OPAL_HAVE_WEAK_SYMBOLS && OMPI_PROFILING_DEFINES
#pragma weak MPI_Comm_join = PMPI_Comm_join
#endif

#if OMPI_PROFILING_DEFINES
#include "ompi/mpi/c/profile/defines.h"
#endif

static const char FUNC_NAME[] = "MPI_Comm_join";

static int ompi_socket_send (int fd, char *buf, int len );
static int ompi_socket_recv (int fd, char *buf, int len );

int MPI_Comm_join(int fd, MPI_Comm *intercomm) 
{
    int rc;
    uint32_t len, rlen, llen, lrlen;
    int send_first=0;
    char *rport;
    ompi_process_name_t rname, tmp_name;

    ompi_communicator_t *newcomp;
    char port_name[MPI_MAX_PORT_NAME];

    if ( MPI_PARAM_CHECK ) {
        OMPI_ERR_INIT_FINALIZE(FUNC_NAME);

        if ( NULL == intercomm ) {
            return OMPI_ERRHANDLER_INVOKE(MPI_COMM_WORLD, MPI_ERR_ARG, 
                                          FUNC_NAME);
        }
    }

    OPAL_CR_ENTER_LIBRARY();

    /* open a port using the specified tag */
    if (OMPI_SUCCESS != (rc = ompi_dpm.open_port(port_name, OMPI_COMM_JOIN_TAG))) {
        OPAL_CR_EXIT_LIBRARY();
        return rc;
    }
    
    /* send my process name */
    tmp_name = *OMPI_PROC_MY_NAME;
    OMPI_PROCESS_NAME_HTON(tmp_name);
    ompi_socket_send(fd, (char*) &tmp_name, sizeof(tmp_name));

    /* recv the remote name */
    ompi_socket_recv(fd, (char*) &rname, sizeof(rname));
    OMPI_PROCESS_NAME_NTOH(rname);

    /* compare the two to get send_first */
    if (OMPI_PROC_MY_NAME->jobid == rname.jobid) {
        if (OMPI_PROC_MY_NAME->vpid < rname.vpid) {
            send_first = true;
        } else if (OMPI_PROC_MY_NAME->vpid == rname.vpid) {
            /* joining to myself is not allowed */
            *intercomm = MPI_COMM_NULL;
            OPAL_CR_EXIT_LIBRARY();
            return MPI_ERR_INTERN;
        } else {
            send_first = false;
        }
    } else if (OMPI_PROC_MY_NAME->jobid < rname.jobid) {
        send_first = true;
    }

    /* sendrecv port-name through the socket connection.
       Need to determine somehow how to avoid a potential deadlock
       here. */
    llen   = (uint32_t)(strlen(port_name)+1);
    len    = htonl(llen);
    
    ompi_socket_send( fd, (char *) &len, sizeof(uint32_t));
    ompi_socket_recv (fd, (char *) &rlen, sizeof(uint32_t));

    lrlen  = ntohl(rlen);
    rport = (char *) malloc (lrlen);
    if ( NULL == rport ) {
        *intercomm = MPI_COMM_NULL;
        OPAL_CR_EXIT_LIBRARY();
        return MPI_ERR_INTERN;
    }

    /* Assumption: socket_send should not block, even if the socket 
       is not configured to be non-blocking, because the message length are
       so short. */
    ompi_socket_send (fd, port_name, llen);
    ompi_socket_recv (fd, rport, lrlen);
    
    /* use the port we received to connect/accept */
    rc = ompi_dpm.connect_accept (MPI_COMM_SELF, 0, rport, send_first, &newcomp);
    
    
    free ( rport );

    *intercomm = newcomp;
    OMPI_ERRHANDLER_RETURN (rc, MPI_COMM_SELF, rc, FUNC_NAME);
}


static int ompi_socket_send (int fd, char *buf, int len )
{
    int num;
    size_t s_num;
    ssize_t a;
    char *c_ptr;
    int ret = OMPI_SUCCESS;
    
    num   = len;
    c_ptr = buf;

    do {
        s_num = (size_t) num;
        a = write ( fd, c_ptr, s_num ); 
        if ( a == -1 ) {
            if ( errno == EINTR ) {
                /* Catch EINTR on, mainly on IBM RS6000 */
                continue;
            }
#ifdef __SR8000
            else if ( errno == EWOULDBLOCK ) {
                /*Catch EWOULDBLOCK on Hitachi SR8000 */
                continue;
            }
            else if ( errno == EAGAIN ) {
                /* Catch EAGAIN on Hitachi SR8000 */
                continue;
            }
#endif
            else {
                /* Another error occured */
                fprintf (stderr,"ompi_socket_send: error while writing to socket" 
                         " error:%s", strerror (errno) );
                return MPI_ERR_OTHER;
            }
        }
        num      -= a;
        c_ptr    += a;
    }   while ( num > 0 );
    

    if ( num < 0 )  {
        fprintf (stderr, "ompi_socket_send: more data written then available");
        ret = MPI_ERR_INTERN;
    }

    return ret;
}

static int ompi_socket_recv (int fd, char *buf, int len )
{
    int num;
    size_t s_num;
    ssize_t a;
    char *c_ptr;
    int ret = MPI_SUCCESS;
    
    num      = len;
    c_ptr      = buf;

    do {
        s_num = (size_t ) num;
        a = read ( fd, c_ptr, s_num ); 
        if ( a == -1 ) {
            if ( errno == EINTR ) {
                /* Catch EINTR on, mainly on IBM RS6000 */
                continue;
            }
#ifdef __SR8000
            else if ( errno == EWOULDBLOCK ) {
                /*Catch EWOULDBLOCK on Hitachi SR8000 */
                continue;
            }
            else if ( errno == EAGAIN ) {
                /* Catch EAGAIN on Hitachi SR8000 */
                continue;
            }
#endif
            else {
                /* Another error occured */
                fprintf (stderr,"ompi_socket_recv: error while reading from socket" 
                         " error:%s", strerror (errno) );
                return MPI_ERR_OTHER;
            }
        }
        num    -= a;
        c_ptr  += a;
    }   while ( num > 0 );

    if ( num < 0 )  {
        fprintf (stderr, "ompi_socket_recv: more data read then available");
        ret = MPI_ERR_INTERN;
    }

    return ret;
}