inode.c

来自「基于组件方式开发操作系统的OSKIT源代码」· C语言 代码 · 共 1,432 行 · 第 1/3 页

/*
 *  linux/fs/isofs/inode.c
 *
 *  (C) 1991  Linus Torvalds - minix filesystem
 *      1992, 1993, 1994  Eric Youngdale Modified for ISO 9660 filesystem.
 *      1994  Eberhard Moenkeberg - multi session handling.
 *      1995  Mark Dobie - allow mounting of some weird VideoCDs and PhotoCDs.
 *	1997  Gordon Chaffee - Joliet CDs
 *	1998  Eric Lammerts - ISO 9660 Level 3
 */

#include <linux/config.h>
#include <linux/module.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 <linux/cdrom.h>
#include <linux/init.h>
#include <linux/nls.h>
#include <linux/ctype.h>

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

/*
 * We have no support for "multi volume" CDs, but more and more disks carry
 * wrong information within the volume descriptors.
 */
#define IGNORE_WRONG_MULTI_VOLUME_SPECS
#define BEQUIET

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

static int isofs_hashi(struct dentry *parent, struct qstr *qstr);
static int isofs_hash(struct dentry *parent, struct qstr *qstr);
static int isofs_cmpi(struct dentry *dentry, struct qstr *a, struct qstr *b);
static int isofs_cmp(struct dentry *dentry, struct qstr *a, struct qstr *b);

#ifdef CONFIG_JOLIET
static int isofs_hashi_ms(struct dentry *parent, struct qstr *qstr);
static int isofs_hash_ms(struct dentry *parent, struct qstr *qstr);
static int isofs_cmpi_ms(struct dentry *dentry, struct qstr *a, struct qstr *b);
static int isofs_cmp_ms(struct dentry *dentry, struct qstr *a, struct qstr *b);
#endif

void isofs_put_super(struct super_block *sb)
{
#ifdef CONFIG_JOLIET
	if (sb->u.isofs_sb.s_nls_iocharset) {
		unload_nls(sb->u.isofs_sb.s_nls_iocharset);
		sb->u.isofs_sb.s_nls_iocharset = NULL;
	}
#endif

#ifdef LEAK_CHECK
	printk("Outstanding mallocs:%d, outstanding buffers: %d\n",
	       check_malloc, check_bread);
#endif

	MOD_DEC_USE_COUNT;
	return;
}

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

static struct dentry_operations isofs_dentry_ops[] = {
	{
		NULL,			/* d_revalidate */
		isofs_hash,
		isofs_cmp,
		NULL			/* d_delete */
	},
	{
		NULL,			/* d_revalidate */
		isofs_hashi,
		isofs_cmpi,
		NULL			/* d_delete */
	},
#ifdef CONFIG_JOLIET
	{
		NULL,			/* d_revalidate */
		isofs_hash_ms,
		isofs_cmp_ms,
		NULL			/* d_delete */
	},
	{
		NULL,			/* d_revalidate */
		isofs_hashi_ms,
		isofs_cmpi_ms,
		NULL			/* d_delete */
	}
#endif
};

struct iso9660_options{
	char map;
	char rock;
	char joliet;
	char cruft;
	char unhide;
	unsigned char check;
	unsigned int blocksize;
	mode_t mode;
	gid_t gid;
	uid_t uid;
	char *iocharset;
	unsigned char utf8;
};

/*
 * Compute the hash for the isofs name corresponding to the dentry.
 */
static int
isofs_hash_common(struct dentry *dentry, struct qstr *qstr, int ms)
{
	const char *name;
	int len;

	len = qstr->len;
	name = qstr->name;
	if (ms) {
		while (len && name[len-1] == '.')
			len--;
	}

	qstr->hash = full_name_hash(name, len);

	return 0;
}

/*
 * Compute the hash for the isofs name corresponding to the dentry.
 */
static int
isofs_hashi_common(struct dentry *dentry, struct qstr *qstr, int ms)
{
	const char *name;
	int len;
	char c;
	unsigned long hash;

	len = qstr->len;
	name = qstr->name;
	if (ms) {
		while (len && name[len-1] == '.')
			len--;
	}

	hash = init_name_hash();
	while (len--) {
		c = tolower(*name++);
		hash = partial_name_hash(tolower(c), hash);
	}
	qstr->hash = end_name_hash(hash);

	return 0;
}

/*
 * Case insensitive compare of two isofs names.
 */
static int
isofs_cmpi_common(struct dentry *dentry,struct qstr *a,struct qstr *b,int ms)
{
	int alen, blen;

	/* A filename cannot end in '.' or we treat it like it has none */
	alen = a->len;
	blen = b->len;
	if (ms) {
		while (alen && a->name[alen-1] == '.')
			alen--;
		while (blen && b->name[blen-1] == '.')
			blen--;
	}
	if (alen == blen) {
		if (strnicmp(a->name, b->name, alen) == 0)
			return 0;
	}
	return 1;
}

/*
 * Case sensitive compare of two isofs names.
 */
static int
isofs_cmp_common(struct dentry *dentry,struct qstr *a,struct qstr *b,int ms)
{
	int alen, blen;

	/* A filename cannot end in '.' or we treat it like it has none */
	alen = a->len;
	blen = b->len;
	if (ms) {
		while (alen && a->name[alen-1] == '.')
			alen--;
		while (blen && b->name[blen-1] == '.')
			blen--;
	}
	if (alen == blen) {
		if (strncmp(a->name, b->name, alen) == 0)
			return 0;
	}
	return 1;
}

static int
isofs_hash(struct dentry *dentry, struct qstr *qstr)
{
	return isofs_hash_common(dentry, qstr, 0);
}

static int
isofs_hashi(struct dentry *dentry, struct qstr *qstr)
{
	return isofs_hashi_common(dentry, qstr, 0);
}

static int
isofs_cmp(struct dentry *dentry,struct qstr *a,struct qstr *b)
{
	return isofs_cmp_common(dentry, a, b, 0);
}

static int
isofs_cmpi(struct dentry *dentry,struct qstr *a,struct qstr *b)
{
	return isofs_cmpi_common(dentry, a, b, 0);
}

#ifdef CONFIG_JOLIET
static int
isofs_hash_ms(struct dentry *dentry, struct qstr *qstr)
{
	return isofs_hash_common(dentry, qstr, 1);
}

static int
isofs_hashi_ms(struct dentry *dentry, struct qstr *qstr)
{
	return isofs_hashi_common(dentry, qstr, 1);
}

static int
isofs_cmp_ms(struct dentry *dentry,struct qstr *a,struct qstr *b)
{
	return isofs_cmp_common(dentry, a, b, 1);
}

static int
isofs_cmpi_ms(struct dentry *dentry,struct qstr *a,struct qstr *b)
{
	return isofs_cmpi_common(dentry, a, b, 1);
}
#endif

static int parse_options(char *options, struct iso9660_options * popt)
{
	char *this_char,*value;

	popt->map = 'n';
	popt->rock = 'y';
	popt->joliet = 'y';
	popt->cruft = 'n';
	popt->unhide = 'n';
	popt->check = 'u';		/* unset */
	popt->blocksize = 1024;
	popt->mode = S_IRUGO | S_IXUGO; /* r-x for all.  The disc could
					   be shared with DOS machines so
					   virtually anything could be
					   a valid executable. */
	popt->gid = 0;
	popt->uid = 0;
	popt->iocharset = NULL;
	popt->utf8 = 0;
	if (!options) return 1;
	for (this_char = strtok(options,","); this_char; this_char = strtok(NULL,",")) {
	        if (strncmp(this_char,"norock",6) == 0) {
		  popt->rock = 'n';
		  continue;
		}
	        if (strncmp(this_char,"nojoliet",8) == 0) {
		  popt->joliet = 'n';
		  continue;
		}
	        if (strncmp(this_char,"unhide",6) == 0) {
		  popt->unhide = 'y';
		  continue;
		}
	        if (strncmp(this_char,"cruft",5) == 0) {
		  popt->cruft = 'y';
		  continue;
		}
	        if (strncmp(this_char,"utf8",4) == 0) {
		  popt->utf8 = 1;
		  continue;
		}
		if ((value = strchr(this_char,'=')) != NULL)
			*value++ = 0;

#ifdef CONFIG_JOLIET
		if (!strcmp(this_char,"iocharset") && value) {
			popt->iocharset = value;
			while (*value && *value != ',')
				value++;
			if (value == popt->iocharset)
				return 0;
			*value = 0;
		} else
#endif
		if (!strcmp(this_char,"map") && value) {
			if (value[0] && !value[1] && strchr("ano",*value))
				popt->map = *value;
			else if (!strcmp(value,"off")) popt->map = 'o';
			else if (!strcmp(value,"normal")) popt->map = 'n';
			else if (!strcmp(value,"acorn")) popt->map = 'a';
			else return 0;
		}
		else if (!strcmp(this_char,"check") && value) {
			if (value[0] && !value[1] && strchr("rs",*value))
				popt->check = *value;
			else if (!strcmp(value,"relaxed")) popt->check = 'r';
			else if (!strcmp(value,"strict")) popt->check = 's';
			else return 0;
		}
		else if (!strcmp(this_char,"conv") && value) {
			/* no conversion is done anymore;
			   we still accept the same mount options,
			   but ignore them */
			if (value[0] && !value[1] && strchr("btma",*value)) ;
			else if (!strcmp(value,"binary")) ;
			else if (!strcmp(value,"text")) ;
			else if (!strcmp(value,"mtext")) ;
			else if (!strcmp(value,"auto")) ;
			else return 0;
		}
		else if (value &&
			 (!strcmp(this_char,"block") ||
			  !strcmp(this_char,"mode") ||
			  !strcmp(this_char,"uid") ||
			  !strcmp(this_char,"gid"))) {
		  char * vpnt = value;
		  unsigned int ivalue = simple_strtoul(vpnt, &vpnt, 0);
		  if (*vpnt) return 0;
		  switch(*this_char) {
		  case 'b':
		    if (   ivalue != 512
			&& ivalue != 1024
			&& ivalue != 2048) return 0;
		    popt->blocksize = ivalue;
		    break;
		  case 'u':
		    popt->uid = ivalue;
		    break;
		  case 'g':
		    popt->gid = ivalue;
		    break;
		  case 'm':
		    popt->mode = ivalue;
		    break;
		  }
		}
		else return 1;
	}
	return 1;
}

/*
 * look if the driver can tell the multi session redirection value
 *
 * don't change this if you don't know what you do, please!
 * Multisession is legal only with XA disks.
 * A non-XA disk with more than one volume descriptor may do it right, but
 * usually is written in a nowhere standardized "multi-partition" manner.
 * Multisession uses absolute addressing (solely the first frame of the whole
 * track is #0), multi-partition uses relative addressing (each first frame of
 * each track is #0), and a track is not a session.
 *
 * A broken CDwriter software or drive firmware does not set new standards,
 * at least not if conflicting with the existing ones.
 *
 * [e-mail]
 */
#define WE_OBEY_THE_WRITTEN_STANDARDS 1

static unsigned int isofs_get_last_session(kdev_t dev)
{
#ifdef OSKIT
  return 0;
#else /* not OSKIT */
  struct cdrom_multisession ms_info;
  unsigned int vol_desc_start;
  struct inode inode_fake;
  struct file_operations *fops;
  extern struct file_operations * get_blkfops(unsigned int);
  int i;

  vol_desc_start=0;
  fops = get_blkfops(MAJOR(dev));
  if (fops && fops->ioctl)
    {
      /* Whoops.  We must save the old FS, since otherwise
       * we would destroy the kernels idea about FS on root
       * mount in read_super... [chexum]
       */
      mm_segment_t old_fs=get_fs();
      inode_fake.i_rdev=dev;
      ms_info.addr_format=CDROM_LBA;
      set_fs(KERNEL_DS);
      i=get_blkfops(MAJOR(dev))->ioctl(&inode_fake,
				       NULL,
				       CDROMMULTISESSION,
				       (unsigned long) &ms_info);
      set_fs(old_fs);
#if 0
      printk("isofs.inode: CDROMMULTISESSION: rc=%d\n",i);
      if (i==0)
	{
	  printk("isofs.inode: XA disk: %s\n", ms_info.xa_flag ? "yes":"no");
	  printk("isofs.inode: vol_desc_start = %d\n", ms_info.addr.lba);
	}
#endif
      if (i==0)
#if WE_OBEY_THE_WRITTEN_STANDARDS
        if (ms_info.xa_flag) /* necessary for a valid ms_info.addr */
#endif
          vol_desc_start=ms_info.addr.lba;
    }
  return vol_desc_start;
#endif /* OSKIT */
}

/*
 * Initialize the superblock and read the root inode.
 *
 * Note: a check_disk_change() has been done immediately prior
 * to this call, so we don't need to check again.
 */
struct super_block *isofs_read_super(struct super_block *s, void *data,
				     int silent)
{
	kdev_t				dev = s->s_dev;
	struct buffer_head	      * bh = NULL, *pri_bh = NULL;
	struct hs_primary_descriptor  * h_pri = NULL;
	struct iso_primary_descriptor * pri = NULL;
	struct iso_supplementary_descriptor *sec = NULL;
	struct iso_directory_record   * rootp;
	int				joliet_level = 0;
	int				high_sierra;
	int				iso_blknum, block;
	int				orig_zonesize;
	int				table;
	unsigned int			blocksize, blocksize_bits;
	unsigned int			vol_desc_start;
	unsigned long			first_data_zone;
	struct inode		      * inode;
	struct iso9660_options		opt;