getlabel.iso9660.c

linux下的一个mount工具

/*
 * $Id: getlabel.iso9660.c,v 1.1.1.1 2000/09/13 19:36:43 lyonel Exp $
 *
 * based on isoinfo.c by Steffen Solyga <[e-mail]>
 *
 * Copyright (C) 2000 Lyonel Vincent <[e-mail]>
 * 
 * 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 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */


#undef	DEBUG

#include <unistd.h>		/* read(), write(), close(), STDIN_FILENO */
#include <sys/types.h>		/* open() */
#include <sys/stat.h>		/* open() */
#include <fcntl.h>		/* open(), O_RDONLY */
#include <linux/ioctl.h>	/* ioctl() */
#include <linux/cdrom.h>	/* multisession handling*/
#include "iso_fs.h"		/* iso9660 structures & definitions (mkisofs)*/

#define	ISO_BLOCK_SIZE	2048
#define	ISO_PD_BLOCK	16			/* PD = primary desciptor */

#define	ISO_STR( A )	iso_str( (A), sizeof(A) )

static unsigned int isofs_get_last_session(int fd)
{
	struct cdrom_multisession ms_info;
	unsigned int vol_desc_start = 0;

	if(ioctl(fd, CDROMMULTISESSION, &ms_info)==0)
		if (ms_info.xa_flag) /* necessary for a valid ms_info.addr */
			vol_desc_start=ms_info.addr.lba;

	return vol_desc_start;
}

static long
iso_num_733( char* p ) {
  return(   (p[0] & 0xffL)
          | (p[1] & 0xffL) <<  8
          | (p[2] & 0xffL) << 16
          | (p[3] & 0xffL) << 24 );
}

int
isonum_711 (char * p)
{
        return (*p & 0xff);
}


static char*
iso_str( char* p, int n ) {
  static char string[256];
  int i= 0;
  while( i < n ) string[i]= p[i++];
  string[i--]= '\0';
  while( string[i] == ' ' ) string[i--]= '\0';
  return( string );
}


int iso9660_getlabel(int in_fd, char * label)
{
	int result=0;
	unsigned int iso_blknum;
	unsigned int vol_desc_start;

	vol_desc_start = isofs_get_last_session(in_fd);

	for (iso_blknum=vol_desc_start+ISO_PD_BLOCK; iso_blknum<vol_desc_start+100; iso_blknum++)
	{
		char buffer[ISO_BLOCK_SIZE];
		struct hs_volume_descriptor   * hdp;
		struct iso_volume_descriptor  * vdp;

		if(lseek(in_fd,iso_blknum*ISO_BLOCK_SIZE,SEEK_SET) == -1)
			break;
  		if(read(in_fd,&buffer,sizeof(buffer)) != sizeof(buffer))
			break;

		vdp = (struct iso_volume_descriptor *)buffer;
		hdp = (struct hs_volume_descriptor *)buffer;

		/* first we test for ISO9660 */
		if(strncmp(vdp->id, ISO_STANDARD_ID, sizeof(vdp->id)) == 0)
		{
			if(isonum_711(vdp->type) == ISO_VD_END)
				break;
			if(isonum_711(vdp->type) == ISO_VD_PRIMARY)
			{
				struct iso_primary_descriptor *pri = NULL;
				
				pri = (struct iso_primary_descriptor *)vdp;
				strcpy(label, ISO_STR(pri->volume_id) );

				result = 1;
				break;
			}
		}
		else	/* now we test for High Sierra */
		if(strncmp(hdp->id, HS_STANDARD_ID, sizeof(hdp->id)) == 0)
		{
			struct hs_primary_descriptor * pri = NULL;

			if(isonum_711(hdp->type) != ISO_VD_PRIMARY)
				break;

			pri = (struct hs_primary_descriptor *)vdp;
			strcpy(label, ISO_STR(pri->volume_id) );

			result = 1;
			break;
		}
	}

	return result;
}