How to print HFS Volume header - objective-c

Question

Any one please give code snippet for how to print volume header of HFS+ disk.

Answer 1

I’ve written a small program (based on hfs-183.1) that prints some of the information declared in struct HFSPlusVolumeHeader. The program must be run as root — for instance, via sudo(8):
#include <fcntl.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/stat.h>
#include <hfs/hfs_format.h>
#include <libkern/OSByteOrder.h>
int main(void) {
int fd;
struct stat stat_buf;
struct HFSPlusVolumeHeader vheader;
const char *vname = "/dev/rdisk0s2";
if (lstat(vname, &stat_buf) == -1) {
fprintf(stderr, "Couldn't stat %s\n", vname);
perror(NULL);
exit(1);
}
if ((stat_buf.st_mode & S_IFMT) != S_IFCHR) {
fprintf(stderr, "%s is not a raw char device\n", vname);
perror(NULL);
exit(2);
}
fd = open(vname, O_RDONLY);
if (fd == -1) {
fprintf(stderr, "%s couldn't be opened for reading\n", vname);
perror(NULL);
exit(3);
}
// The volume header starts at offset 1024
if (pread(fd, &vheader, sizeof vheader, 1024) != sizeof vheader) {
fprintf(stderr, "couldn't read %s's volume header\n", vname);
perror(NULL);
exit(4);
}
printf("fileCount = %u\n"
"folderCount = %u\n"
"blockSize = %u\n"
"totalBlocks = %u\n"
"freeBlocks = %u\n",
OSSwapBigToHostInt32(vheader.fileCount),
OSSwapBigToHostInt32(vheader.folderCount),
OSSwapBigToHostInt32(vheader.blockSize),
OSSwapBigToHostInt32(vheader.totalBlocks),
OSSwapBigToHostInt32(vheader.freeBlocks));
close(fd);
return 0;
}
The header file <hfs/hfs_format.h> declares struct HFSPlusVolumeHeader. See this file for the complete list of fields inside a HFS+ volume header.

Answer 2

The system call getattrlist() might give you the information you need.