/**
 * Author: Martin Drab <martin.drab@fjfi.cvut.cz> (c) 2015
 *
 * This code is provided freely as a tutorial for use on the Hyperion cluster
 * at the Dept. of Solid State Engineering and Dept. of Mathematics
 * of the Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague.
 *
 * Feel free to modify it for your own use.
 */

#include <mpi.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/statvfs.h>

int
main (int argc, char **argv)
{
	int _Ret;
	int _NProc;					/*!< Number of processes in this MPI group */
	int _Rank;					/*!< Number/ID of our process */
	char _CPUName[MPI_MAX_PROCESSOR_NAME+1];	/*!< Name of the processor where we run */
	int x;						/*!< Actual size of the string within the _CPUName */
	char *_EnvTMPDIR;
	char *_EnvTMP;
	struct stat _StatTMP;
	struct statvfs _StatVFSTMP;

	/* Initialize MPI */
	_Ret = MPI_Init (&argc, &argv);
	if (_Ret != MPI_SUCCESS) {
		fprintf (stderr, "*** ERROR: Failed to call MPI_Init() with error code: %i\n", _Ret);
		MPI_Abort (MPI_COMM_WORLD, _Ret);
	}

	/* Get info about the process */
	MPI_Comm_size (MPI_COMM_WORLD, &_NProc);
	MPI_Comm_rank (MPI_COMM_WORLD, &_Rank);
	MPI_Get_processor_name (_CPUName, &x);
	_CPUName[x] = 0;

	_EnvTMPDIR = getenv ("TMPDIR");
	_EnvTMP = getenv ("TMP");
	_Ret = stat (_EnvTMP, &_StatTMP);
	if (_Ret) {
		fprintf (stderr, "*** ERROR [%i/%i]: Failed to get stat() of TMP. (%i)", _Rank, _NProc, _Ret);
		MPI_Abort (MPI_COMM_WORLD, _Ret);
	}
	_Ret = statvfs (_EnvTMP, &_StatVFSTMP);
	if (_Ret) {
		fprintf (stderr, "*** ERROR [%i/%i]: Failed to get statvfs() of TMP. (%i)", _Rank, _NProc, _Ret);
		MPI_Abort (MPI_COMM_WORLD, _Ret);
	}

	printf ("Process %i/%i running on %s. TMP=\"%s\", TMPDIR=\"%s\", mode=0%o, UID=%u, GID=%u, available %.2f MB\n",
			_Rank, _NProc, _CPUName, _EnvTMP, _EnvTMPDIR, (unsigned int)_StatTMP.st_mode & 07777,
			(unsigned int)_StatTMP.st_uid, (unsigned int)_StatTMP.st_gid,
			(double)((unsigned long long)_StatVFSTMP.f_bavail * _StatVFSTMP.f_bsize)/(1024.0*1024.0));

	/* Destroy MPI */
	MPI_Finalize ();

	return 0;
}