get filesystem usage under linux

fsusage.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/statvfs.h>

#include "pstatvfs.h"

#define ARGLEN 255

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

        struct statvfs stat;

        long int blocksize, bfree, bavail, free, avail;

        char path[ARGLEN] = "/local";

        if (argc == 2) {
                strncpy(path, argv[1], ARGLEN);
                path[ARGLEN] = '\0';
        }

        if (statvfs(path, &stat) < 0) {
                perror("Error in statvfs");
                exit(EXIT_FAILURE);
        }

        pstatvfs(&stat);

        blocksize = stat.f_bsize;
        bfree = stat.f_bfree;
        bavail = stat.f_bavail;

        free = bfree * (blocksize / 1024);
        avail = bavail * (blocksize / 1024);

        printf("blocksize: %ld\n", blocksize);
        printf("bfree:     %ld\n", bfree);
        printf("bavail:    %ld\n", bavail);

        printf("\nConversion to KB:\n");
        printf("free:      %ld\n", free);
        printf("avail:     %ld\n", avail);

        exit(EXIT_SUCCESS);
}