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

/*

 *

 *  (C) 2009 by Argonne National Laboratory.

 *      See COPYRIGHT in top-level directory.

 */

#include "mpi.h"

#include <stdio.h>

#include <stdlib.h>

#include "mpitest.h"

/*

static char MTEST_Descrip[] = "Test error reporting from faults with point to point communication";

*/

int ReportErr(int errcode, const char name[]);

int main(int argc, char *argv[])

{

    int wrank, wsize, rank, size, color;

    int j, tmp;

    int err, toterrs, errs = 0;

    MPI_Comm newcomm;

    MTest_Init(&argc, &argv);

    MPI_Comm_size(MPI_COMM_WORLD, &wsize);

    MPI_Comm_rank(MPI_COMM_WORLD, &wrank);

    /* Color is 0 or 1; 1 will be the processes that "fault" */

    /* process 0 and wsize/2+1...wsize-1 are in non-faulting group */

    color = (wrank > 0) && (wrank <= wsize / 2);

    MPI_Comm_split(MPI_COMM_WORLD, color, wrank, &newcomm);

    MPI_Comm_size(newcomm, &size);

    MPI_Comm_rank(newcomm, &rank;;

    /* Set errors return on COMM_WORLD and the new comm */

    MPI_Comm_set_errhandler(MPI_COMM_WORLD, MPI_ERRORS_RETURN);

    MPI_Comm_set_errhandler(newcomm, MPI_ERRORS_RETURN);

    err = MPI_Barrier(MPI_COMM_WORLD);

    if (err)

        errs += ReportErr(err, "Barrier");

    if (color) {

        /* Simulate a fault on some processes */

        exit(1);

    } else {

        /* To improve the chance that the "faulted" processes will have

         * exited, wait for 1 second */

        MTestSleep(1);

    }

    /* Can we still use newcomm? */

    for (j = 0; j < rank; j++) {

        err = MPI_Recv(&tmp, 1, MPI_INT, j, 0, newcomm, MPI_STATUS_IGNORE);

        if (err)

            errs += ReportErr(err, "Recv");

    }

    for (j = rank + 1; j < size; j++) {

        err = MPI_Send(&rank, 1, MPI_INT, j, 0, newcomm);

        if (err)

            errs += ReportErr(err, "Recv");

    }

    /* Now, try sending in MPI_COMM_WORLD on dead processes */

    /* There is a race condition here - we don't know for sure that the faulted

     * processes have exited.  However, we can ensure a failure by using

     * synchronous sends - the sender will wait until the reciever handles

     * receives the message, which will not happen (the process will exit

     * without matching the message, even if it has not yet exited). */

    for (j = 1; j <= wsize / 2; j++) {

        err = MPI_Ssend(&rank, 1, MPI_INT, j, 0, MPI_COMM_WORLD);

        if (!err) {

            errs++;

            fprintf(stderr, "Ssend succeeded to dead process %d\n", j);

        }

    }

    err = MPI_Allreduce(&errs, &toterrs, 1, MPI_INT, MPI_SUM, newcomm);

    if (err)

        errs += ReportErr(err, "Allreduce");

    MPI_Comm_free(&newcomm);

    MTest_Finalize(toterrs);

    return MTestReturnValue(errs);

}

int ReportErr(int errcode, const char name[])

{

    int errclass, errlen;

    char errmsg[MPI_MAX_ERROR_STRING];

    MPI_Error_class(errcode, &errclass);

    MPI_Error_string(errcode, errmsg, &errlen);

    fprintf(stderr, "In %s, error code %d(class %d) = %s\n", name, errcode, errclass, errmsg);

    return 1;

}