/********************显示超级块信息********************/
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <ext2fs/ext2_fs.h>

typedef unsigned char u8;
typedef unsigned short u16;
typedef unsigned int u32;
typedef struct ext2_super_block SUPER;

SUPER *sp;
char buf[1024];
int fd,blksize,inodesize;

void print(char *s, u32 x)
{
	printf("%-30s = %8d\n",s,x);
}

int super(char *device)
{
	fd = open(device, O_RDONLY);
	if(fd<0){
		printf("open %s failed\n",device); exit(1);
	}
	lseek(fd, (long)1024*1, 0);
	read(fd,buf,1024);
	sp = (SUPER *)buf;
	printf("%-30s = %8x ","s_magic", sp->s_magic);
	if(sp->s_magic != 0xEF53){
		printf("NOT an EXT2 FS\n"); exit(2);
	}
	printf("EXT2 FS OK\n");
	print("s_inodes_count",    sp->s_inodes_count);
	print("s_blocks_count",    sp->s_blocks_count);
	print("s__r_blocks_count", sp->s_r_blocks_count);
	print("s_free_inodes_count",sp->s_free_inodes_count);
	print("s_free_blocks_count",sp->s_free_blocks_count);
	print("s_first_data_block",sp->s_first_data_block);
	print("s_log_block_size",  sp->s_log_block_size);
	print("s_blocks_per_group",sp->s_blocks_per_group);
	print("s_inodes_per_group",sp->s_inodes_per_group);
	print("s_mnt_count",       sp->s_mnt_count);
	print("s_max_mnt_count",   sp->s_max_mnt_count);
	printf("%-30s = %8x\n","s_magic",sp->s_magic);
	printf("s_mtime = %d",ctime(&sp->s_mtime));
	printf("s_wtime = %d",ctime(&sp->s_wtime));
	blksize = 1024 * (1 << sp->s_log_block_size);
	printf("block size = %d\n",blksize);
	printf("inode size = %d\n",sp->s_inode_size);
}

char *device = "mydisk";
int main(int argc, char *argv[])
{
	if(argc>1)
		device = argv[1];
	super(device);
}