Print Inode or file data, using path name

Question

currently the program taking only (./a.out /dev/sdb inode) i want to run like

./a.out /dev/sdb1 /test/t.c inode

(format: ./a.out device-file-name path-on-partition inode/data)

./a.out /dev/sdc2 /test/t.c data

<data printed here, listing of files if it's a directory>

#define _LARGEFILE64_SOURCE     /* See feature_test_macros(7) */
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <errno.h>
#include <linux/fs.h>

//#include <ext2fs/ext2_fs.h>
#include "ext2_fs.h"
int main(int argc, char *argv[]) {
    int fd;
    int count;
    int ino, i;
    int bgno, iindex, inode_size, block_size;
    unsigned long inode_offset;
    struct ext2_super_block sb; 
    struct ext2_inode inode; 
    struct ext2_group_desc bgdesc;

    ino = atoi(argv[2]);
        fd = open(argv[1], O_RDONLY); // argv[1] = /dev/sdb1 
    if(fd == -1) {
        perror("readsuper:");
        exit(errno);
    }

    lseek64(fd, 1024, SEEK_CUR);
    printf("size of super block = %lu\n", sizeof(struct ext2_super_block));
    count = read(fd, &sb, sizeof(struct ext2_super_block));
    printf("Magic: %x\n", sb.s_magic);
    printf("Inodes Count: %d\n", sb.s_inodes_count);
    printf("size of BG DESC = %lu\n", sizeof(struct ext2_group_desc));
    inode_size = sb.s_inode_size;
    block_size = 1024 << sb.s_log_block_size;

    bgno = (ino -1) / sb.s_inodes_per_group;
    iindex = (ino -1) % sb.s_inodes_per_group;
    lseek64(fd, 1024 + block_size + bgno * sizeof(bgdesc), SEEK_SET);
    count = read(fd, &bgdesc, sizeof(struct ext2_group_desc));
    printf("Inode Table: %d\n", bgdesc.bg_inode_table); 

    inode_offset = bgdesc.bg_inode_table  * block_size + iindex * inode_size; 
    lseek64(fd, inode_offset, SEEK_SET);
    read(fd, &inode, sizeof(inode));    
    printf("size of file %d \n", inode.i_size);
    printf(" number of blocks %d , blocks: ", inode.i_blocks);
    for(i = 0; i < inode.i_blocks; i++) 
        printf("%d, ", inode.i_block[i]);
    close(fd); 
}