/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */

/*

 *  (C) 2008 by Argonne National Laboratory.

 *      See COPYRIGHT in top-level directory.

 */

/* Test from Edric Ellis

   To launch,

   Run multiple copies of "testconnect" should be run something like this:

   Path/to/testconnect /full/path/to/shared/file N

   where each instance has one process and N instances are run

*/

#include "mpi.h"

#include <stdio.h>

#include <signal.h>

#include <stdlib.h>

#include <unistd.h>

char *fname;

int cachedRank = -1;

MPI_Comm comm;

void term_handler(int);

void segv_handler(int);

void term_handler(int sig)

{

    if (sig) {

        printf("Saw signal %d\n", sig);

    }

    printf("removing file: %s\n", fname);

    fflush(stdout);

    unlink(fname);

    if (sig != 0) {

        MPI_Abort(comm, 42);

        exit(0);

    }

}

void segv_handler(int sig)

{

    printf("SEGV detected!\n");

    fflush(stdout);

}

int main(int argc, char **argv)

{

    MPI_Comm tmp;

    int size = 0;

    char portName[MPI_MAX_PORT_NAME];

    char *port = &portName[0];

    int doPrint = 1;

    int totalSize = 0;

    int myNum = -1;

    FILE *fh;

    if (argc < 4) {

        printf("Please call with a filename for the port\n");

        exit(1);

    }

    fname = argv[1];

    totalSize = atoi(argv[2]);

    if (argv[3])

        myNum = atoi(argv[3]);

    printf("[%d] Waiting for: %d\n", myNum, totalSize);

    MPI_Init(0, 0);

    /* the existance of the file is used to decide which processes

     * first do a connect to the root process.  */

    fh = fopen(fname, "rt");

    if (fh == NULL) {

        fh = fopen(fname, "wt");

        MPI_Open_port(MPI_INFO_NULL, portName);

        port = portName;

        fprintf(fh, "%s\n", portName);

        fclose(fh);

        if (doPrint) {

            printf("[%d] Wrote port %s to %s\n", myNum, port, fname);

            fflush(stdout);

        }

        comm = MPI_COMM_WORLD;

    } else {

        char *cerr;

        cerr = fgets(port, MPI_MAX_PORT_NAME, fh);

        fclose(fh);

        if (doPrint) {

            printf("[%d] about to connect: Port from %s is: %s\n", myNum, fname, port);

            fflush(stdout);

        }

        MPI_Comm_connect(port, MPI_INFO_NULL, 0, MPI_COMM_WORLD, &tmp);

        if (doPrint) {

            printf("[%d] connect-side: about to perform intercomm merge\n", myNum);

            fflush(stdout);

        }

        MPI_Intercomm_merge(tmp, 1, &comm);

        if (doPrint) {

            printf("[%d] connect-side: intercomm merge complete\n", myNum);

            fflush(stdout);

        }

        MPI_Comm_free(&tmp);

    }

    MPI_Comm_size(comm, &size);

    while (size < totalSize) {

        MPI_Comm_accept(port, MPI_INFO_NULL, 0, comm, &tmp);

        if (doPrint) {

            printf("[%d] accept-side: about to perform intercomm merge\n", myNum);

            fflush(stdout);

        }

        MPI_Intercomm_merge(tmp, 0, &comm);

        if (doPrint) {

            printf("[%d] accept-side: about to perform intercomm merge\n", myNum);

            fflush(stdout);

        }

        MPI_Comm_rank(comm, &cachedRank);

        MPI_Comm_free(&tmp);

        MPI_Comm_size(comm, &size);

        if (doPrint) {

            printf("[%d] Size of comm is %d\n", myNum, size);

            fflush(stdout);

        }

    }

    printf("[%d] All done.\n", myNum);

    fflush(stdout);

    term_handler(0);

    MPI_Finalize();

    return 0;

}