inode.c

Linux 1.0 内核C源代码 Linux最早版本代码 由Linus Torvalds亲自书写的

/*
 *  linux/fs/isofs/inode.c
 * 
 *  (C) 1992  Eric Youngdale Modified for ISO9660 filesystem.
 *
 *  (C) 1991  Linus Torvalds - minix filesystem
 */

#include <linux/config.h>
#include <linux/stat.h>
#include <linux/sched.h>
#include <linux/iso_fs.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/locks.h>
#include <linux/malloc.h>
#include <linux/errno.h>

#include <asm/system.h>
#include <asm/segment.h>

#if defined(CONFIG_BLK_DEV_SR)
extern int check_cdrom_media_change(int, int);
#endif
#if defined(CONFIG_CDU31A)
extern int check_cdu31a_media_change(int, int);
#endif
#if defined(CONFIG_MCD)
extern int check_mcd_media_change(int, int);
#endif
#if defined (CONFIG_SBPCD)
extern int check_sbpcd_media_change(int, int);
#endif CONFIG_SBPCD

#ifdef LEAK_CHECK
static int check_malloc = 0;
static int check_bread = 0;
#endif

void isofs_put_super(struct super_block *sb)
{
	lock_super(sb);

#ifdef LEAK_CHECK
	printk("Outstanding mallocs:%d, outstanding buffers: %d\n", 
	       check_malloc, check_bread);
#endif
	sb->s_dev = 0;
	unlock_super(sb);
	return;
}

static struct super_operations isofs_sops = { 
	isofs_read_inode,
	NULL,			/* notify_change */
	NULL,			/* write_inode */
	NULL,			/* put_inode */
	isofs_put_super,
	NULL,			/* write_super */
	isofs_statfs,
	NULL
};



static int parse_options(char *options,char *map,char *conversion, char * rock, char * cruft, unsigned int * blocksize)
{
	char *this_char,*value;

	*map = 'n';
	*rock = 'y';
	*cruft = 'n';
	*conversion = 'a';
	*blocksize = 1024;
	if (!options) return 1;
	for (this_char = strtok(options,","); this_char; this_char = strtok(NULL,",")) {
	        if (strncmp(this_char,"norock",6) == 0) {
		  *rock = 'n';
		  continue;
		};
	        if (strncmp(this_char,"cruft",5) == 0) {
		  *cruft = 'y';
		  continue;
		};
		if ((value = strchr(this_char,'=')) != NULL)
			*value++ = 0;
		if (!strcmp(this_char,"map") && value) {
			if (value[0] && !value[1] && strchr("on",*value))
				*map = *value;
			else if (!strcmp(value,"off")) *map = 'o';
			else if (!strcmp(value,"normal")) *map = 'n';
			else return 0;
		}
		else if (!strcmp(this_char,"conv") && value) {
			if (value[0] && !value[1] && strchr("bta",*value))
				*conversion = *value;
			else if (!strcmp(value,"binary")) *conversion = 'b';
			else if (!strcmp(value,"text")) *conversion = 't';
			else if (!strcmp(value,"mtext")) *conversion = 'm';
			else if (!strcmp(value,"auto")) *conversion = 'a';
			else return 0;
		}
		else if (!strcmp(this_char,"block") && value) {
		  char * vpnt = value;
		  unsigned int ivalue;
		  ivalue = 0;
		  while(*vpnt){
		    if(*vpnt <  '0' || *vpnt > '9') break;
		    ivalue = ivalue * 10 + (*vpnt - '0');
		    vpnt++;
		  };
		  if (*vpnt) return 0;
		  if (ivalue != 1024 && ivalue != 2048) return 0;
		  *blocksize = ivalue;
		}
		else return 0;
	}
	return 1;
}

struct super_block *isofs_read_super(struct super_block *s,void *data,
				     int silent)
{
	struct buffer_head *bh;
	int iso_blknum;
	unsigned int blocksize, blocksize_bits;
	int high_sierra;
	int dev=s->s_dev;
	struct iso_volume_descriptor *vdp;
	struct hs_volume_descriptor *hdp;

	struct iso_primary_descriptor *pri = NULL;
	struct hs_primary_descriptor *h_pri = NULL;

	struct iso_directory_record *rootp;

	char map, conversion, rock, cruft;

	if (!parse_options((char *) data,&map,&conversion, &rock, &cruft, &blocksize)) {
		s->s_dev = 0;
		return NULL;
	}

	blocksize_bits = 0;
	{
	  int i = blocksize;
	  while (i != 1){
	    blocksize_bits++;
	    i >>=1;
	  };
	};
	set_blocksize(dev, blocksize);

	lock_super(s);

	s->u.isofs_sb.s_high_sierra = high_sierra = 0; /* default is iso9660 */

	for (iso_blknum = 16; iso_blknum < 100; iso_blknum++) {
		if (!(bh = bread(dev, iso_blknum << (ISOFS_BLOCK_BITS-blocksize_bits), blocksize))) {
			s->s_dev=0;
			printk("isofs_read_super: bread failed, dev 0x%x iso_blknum %d\n",
			       dev, iso_blknum);
			unlock_super(s);
			return NULL;
		}

		vdp = (struct iso_volume_descriptor *)bh->b_data;
		hdp = (struct hs_volume_descriptor *)bh->b_data;

		
		if (strncmp (hdp->id, HS_STANDARD_ID, sizeof hdp->id) == 0) {
		  if (isonum_711 (hdp->type) != ISO_VD_PRIMARY)
			goto out;
		  if (isonum_711 (hdp->type) == ISO_VD_END)
		        goto out;
		
		        s->u.isofs_sb.s_high_sierra = 1;
			high_sierra = 1;
		        rock = 'n';
		        h_pri = (struct hs_primary_descriptor *)vdp;
			break;
		};
		
		if (strncmp (vdp->id, ISO_STANDARD_ID, sizeof vdp->id) == 0) {
		  if (isonum_711 (vdp->type) != ISO_VD_PRIMARY)
			goto out;
		  if (isonum_711 (vdp->type) == ISO_VD_END)
			goto out;
		
		        pri = (struct iso_primary_descriptor *)vdp;
			break;
	        };

		brelse(bh);
	      }
	if(iso_blknum == 100) {
		if (!silent)
			printk("Unable to identify CD-ROM format.\n");
		s->s_dev = 0;
		unlock_super(s);
		return NULL;
	};
	
	
	if(high_sierra){
	  rootp = (struct iso_directory_record *) h_pri->root_directory_record;
	  if (isonum_723 (h_pri->volume_set_size) != 1) {
	    printk("Multi-volume disks not (yet) supported.\n");
	    goto out;
	  };
	  s->u.isofs_sb.s_nzones = isonum_733 (h_pri->volume_space_size);
	  s->u.isofs_sb.s_log_zone_size = isonum_723 (h_pri->logical_block_size);
	  s->u.isofs_sb.s_max_size = isonum_733(h_pri->volume_space_size);
	} else {
	  rootp = (struct iso_directory_record *) pri->root_directory_record;
	  if (isonum_723 (pri->volume_set_size) != 1) {
	    printk("Multi-volume disks not (yet) supported.\n");
	    goto out;
	  };
	  s->u.isofs_sb.s_nzones = isonum_733 (pri->volume_space_size);
	  s->u.isofs_sb.s_log_zone_size = isonum_723 (pri->logical_block_size);
	  s->u.isofs_sb.s_max_size = isonum_733(pri->volume_space_size);
	}
	
	s->u.isofs_sb.s_ninodes = 0; /* No way to figure this out easily */
	
	s->u.isofs_sb.s_firstdatazone = isonum_733( rootp->extent) << 
		(ISOFS_BLOCK_BITS - blocksize_bits);
	s->s_magic = ISOFS_SUPER_MAGIC;
	
	/* The CDROM is read-only, has no nodes (devices) on it, and since
	   all of the files appear to be owned by root, we really do not want
	   to allow suid.  (suid or devices will not show up unless we have
	   Rock Ridge extensions) */
	
	s->s_flags = MS_RDONLY /* | MS_NODEV | MS_NOSUID */;
	
	if(s->u.isofs_sb.s_log_zone_size != (1 << ISOFS_BLOCK_BITS)) {
		printk("1 <<Block bits != Block size\n");
		goto out;
	};
	
	brelse(bh);
	
	printk("Max size:%ld   Log zone size:%ld\n",
	       s->u.isofs_sb.s_max_size, 
	       s->u.isofs_sb.s_log_zone_size);
	printk("First datazone:%ld   Root inode number %d\n",
	       s->u.isofs_sb.s_firstdatazone,
	       isonum_733 (rootp->extent) << ISOFS_BLOCK_BITS);
	if(high_sierra) printk("Disc in High Sierra format.\n");
	unlock_super(s);
	/* set up enough so that it can read an inode */
	
	s->s_dev = dev;
	s->s_op = &isofs_sops;
	s->u.isofs_sb.s_mapping = map;
	s->u.isofs_sb.s_rock = (rock == 'y' ? 1 : 0);
	s->u.isofs_sb.s_conversion = conversion;
	s->u.isofs_sb.s_cruft = cruft;
	s->s_blocksize = blocksize;
	s->s_blocksize_bits = blocksize_bits;
	s->s_mounted = iget(s, isonum_733 (rootp->extent) << ISOFS_BLOCK_BITS);
	unlock_super(s);

	if (!(s->s_mounted)) {
		s->s_dev=0;
		printk("get root inode failed\n");
		return NULL;
	}
#if defined(CONFIG_BLK_DEV_SR) && defined(CONFIG_SCSI)
	if (MAJOR(s->s_dev) == SCSI_CDROM_MAJOR) {
		/* Check this one more time. */
		if(check_cdrom_media_change(s->s_dev, 0))
		  goto out;
	}
#endif
#if defined(CONFIG_CDU31A)
	if (MAJOR(s->s_dev) == CDU31A_CDROM_MAJOR) {
		/* Check this one more time. */
		if(check_cdu31a_media_change(s->s_dev, 0))
		  goto out;
	}
#endif
#if defined(CONFIG_MCD)
	if (MAJOR(s->s_dev) == MITSUMI_CDROM_MAJOR) {
		/* Check this one more time. */
		if(check_mcd_media_change(s->s_dev, 0))
		  goto out;
	}
#endif
#if defined(CONFIG_SBPCD)
	if (MAJOR(s->s_dev) == MATSUSHITA_CDROM_MAJOR) {
		if (check_sbpcd_media_change(s->s_dev,0))
		  goto out;
	};
#endif CONFIG_SBPCD

	return s;
 out: /* Kick out for various error conditions */
	brelse(bh);
	s->s_dev = 0;
	unlock_super(s);
	return NULL;
}

void isofs_statfs (struct super_block *sb, struct statfs *buf)
{
	put_fs_long(ISOFS_SUPER_MAGIC, &buf->f_type);
	put_fs_long(1 << ISOFS_BLOCK_BITS, &buf->f_bsize);
	put_fs_long(sb->u.isofs_sb.s_nzones, &buf->f_blocks);
	put_fs_long(0, &buf->f_bfree);
	put_fs_long(0, &buf->f_bavail);
	put_fs_long(sb->u.isofs_sb.s_ninodes, &buf->f_files);
	put_fs_long(0, &buf->f_ffree);
	put_fs_long(NAME_MAX, &buf->f_namelen);
	/* Don't know what value to put in buf->f_fsid */
}

int isofs_bmap(struct inode * inode,int block)
{

	if (block<0) {
		printk("_isofs_bmap: block<0");
		return 0;
	}
	return inode->u.isofs_i.i_first_extent + block;
}

void isofs_read_inode(struct inode * inode)
{
	unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
	struct buffer_head * bh;
	struct iso_directory_record * raw_inode;
	unsigned char *pnt = NULL;
	void *cpnt = NULL;
	int high_sierra;
	int block;
	int i;

	block = inode->i_ino >> ISOFS_BUFFER_BITS(inode);
	if (!(bh=bread(inode->i_dev,block, bufsize))) {
	  printk("unable to read i-node block");