#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

int main(int argc, char **argv)
{
        char *disk = NULL;
        int fd;
        uchar_t *buf;
        int requested_size = 512;
	int offset = 0;
        int bytes;

        if (argc < 2) {
                printf("Usage: %s /dev/rdsk/... [bytes to read] [offset]\n");
                exit(1);
        }

        disk = argv[1];
        if (argc > 2) requested_size = atoi(argv[2]);
        if (argc > 3) offset = atoi(argv[3]);
        buf = calloc(requested_size, 1);
        if (buf == NULL) {
                printf("No memory\n");
                exit(1);
        }

        fd = open(disk, O_RDONLY);
        if (fd == -1) {
                perror("open");
                free(buf);
                exit(1);
        }
        if (lseek(fd, offset, SEEK_SET) < 0) {
                perror("lseek");
                close(fd);
                free(buf);
                exit(1);
        }
        bytes = read(fd, buf, requested_size);
        if (bytes == -1) perror("read");
        printf("asked %d, got %d, buf ptr = %p, pid %d\n", requested_size, bytes, buf, getpid());
        close(fd);
        free(buf);
        return(0);
}