getlabel.hfs.c

linux下的一个mount工具

/*
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Library General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */
/*
 * $Id: getlabel.hfs.c,v 1.1.1.1 2000/09/13 19:36:42 lyonel Exp $
 *
 * Copyright (c) 2000, Lyonel VINCENT <[e-mail]>
 *
 * This file may be redistributed under the terms of the GNU Public
 * License.
 *
 */

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdint.h>

typedef uint8_t		UInt8;
typedef int8_t		SInt8;
typedef uint16_t	UInt16;
typedef int16_t		SInt16;
typedef uint16_t	UniChar;
typedef uint32_t	UInt32;
typedef int32_t		SInt32;
typedef uint64_t	UInt64;

/* Signatures used to differentiate between HFS and HFS Plus volumes */

#define kHFSSigWord	(UInt16)0x4244	/* 'BD' in ASCII */

#define BLOCKSIZE	512

/* Master Directory Block (HFS only) - 162 bytes */
/* Stored at sector #2 (3rd sector) */

#pragma pack(2)
struct HFSMasterDirectoryBlock {
	union {
		UInt16 		drSigWord;		/* volume signature */
		UInt8		drSigWord_[2];
	} u;
		
	UInt32 		drCrDate;		/* date and time of volume creation */
	UInt32 		drLsMod;		/* date and time of last modification */
	UInt16 		drAtrb;			/* volume attributes */
	SInt16 		drNmFls;		/* number of files in root folder */
	UInt16 		drVBMSt;		/* first block of volume bitmap */
	UInt16 		drAllocPtr;		/* start of next allocation search */
	UInt16 		drNmAlBlks;		/* number of allocation blocks in volume */
	SInt32 		drAlBlkSiz;		/* size (in bytes) of allocation blocks */
	SInt32 		drClpSiz;		/* default clump size */
	SInt16 		drAlBlSt;		/* first allocation block in volume */
	UInt32 		drNxtCNID;		/* next unused catalog node ID */
	SInt16 		drFreeBks;		/* number of unused allocation blocks */
	char 		drVN[28];		/* volume name */

	/* Master Directory Block extensions for HFS follow */
	/* ... */

};
typedef struct HFSMasterDirectoryBlock	HFSMasterDirectoryBlock;

#define hfsmagic(s)    ((UInt16) s.u.drSigWord_[1] + (((UInt16) s.u.drSigWord_[0]) << 8))

int hfs_getlabel(int fd, char *label) {

	HFSMasterDirectoryBlock mdb;

	if (lseek(fd, 2*BLOCKSIZE, SEEK_SET) != 2*BLOCKSIZE
	    || read(fd, (char *) &mdb, sizeof(mdb)) != sizeof(mdb)
	    || (hfsmagic(mdb) != kHFSSigWord)) {
		return 0;
	}

	strncpy(label, &mdb.drVN[1], (UInt8)mdb.drVN[0]);
	label[(UInt8)mdb.drVN[0]] = '\0';
	return 1;
}