dir.c

Linux Kernel 2.6.9 for OMAP1710

		slots = id & ~0x40;
		if (slots > 20 || !slots)	/* ceil(256 * 2 / 26) */
			goto RecEnd;
		long_slots = slots;
		alias_checksum = ds->alias_checksum;

		slot = slots;
		while (1) {
			int offset;

			slot--;
			offset = slot * 13;
			fat16_towchar(unicode + offset, ds->name0_4, 5);
			fat16_towchar(unicode + offset + 5, ds->name5_10, 6);
			fat16_towchar(unicode + offset + 11, ds->name11_12, 2);

			if (ds->id & 0x40) {
				unicode[offset + 13] = 0;
			}
			if (fat_get_entry(inode,&cpos,&bh,&de,&i_pos) == -1)
				goto EODir;
			if (slot == 0)
				break;
			ds = (struct msdos_dir_slot *) de;
			if (ds->attr !=  ATTR_EXT)
				goto RecEnd;	/* XXX */
			if ((ds->id & ~0x40) != slot)
				goto ParseLong;
			if (ds->alias_checksum != alias_checksum)
				goto ParseLong;
		}
		if (de->name[0] == DELETED_FLAG)
			goto RecEnd;
		if (de->attr ==  ATTR_EXT)
			goto ParseLong;
		if (IS_FREE(de->name) || (de->attr & ATTR_VOLUME))
			goto RecEnd;
		for (sum = 0, i = 0; i < 11; i++)
			sum = (((sum&1)<<7)|((sum&0xfe)>>1)) + de->name[i];
		if (sum != alias_checksum)
			long_slots = 0;
	}

	if ((de->attr & ATTR_HIDDEN) && MSDOS_SB(sb)->options.dotsOK) {
		*ptname++ = '.';
		dotoffset = 1;
	}

	memcpy(work, de->name, sizeof(de->name));
	/* see namei.c, msdos_format_name */
	if (work[0] == 0x05)
		work[0] = 0xE5;
	for (i = 0, j = 0, last = 0, last_u = 0; i < 8;) {
		if (!(c = work[i])) break;
		chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
					&bufuname[j++], opt_shortname,
					de->lcase & CASE_LOWER_BASE);
		if (chl <= 1) {
			ptname[i++] = (!nocase && c>='A' && c<='Z') ? c+32 : c;
			if (c != ' ') {
				last = i;
				last_u = j;
			}
		} else {
			last_u = j;
			for (chi = 0; chi < chl && i < 8; chi++) {
				ptname[i] = work[i];
				i++; last = i;
			}
		}
	}
	i = last;
	j = last_u;
	fat_short2uni(nls_disk, ".", 1, &bufuname[j++]);
	ptname[i++] = '.';
	for (i2 = 0; i2 < 3;) {
		if (!(c = de->ext[i2])) break;
		chl = fat_shortname2uni(nls_disk, &de->ext[i2], 3 - i2,
					&bufuname[j++], opt_shortname,
					de->lcase & CASE_LOWER_EXT);
		if (chl <= 1) {
			i2++;
			ptname[i++] = (!nocase && c>='A' && c<='Z') ? c+32 : c;
			if (c != ' ') {
				last = i;
				last_u = j;
			}
		} else {
			last_u = j;
			for (chi = 0; chi < chl && i2 < 3; chi++) {
				ptname[i++] = de->ext[i2++];
				last = i;
			}
		}
	}
	if (!last)
		goto RecEnd;

	i = last + dotoffset;
	j = last_u;

	lpos = cpos - (long_slots+1)*sizeof(struct msdos_dir_entry);
	if (!memcmp(de->name,MSDOS_DOT,11))
		inum = inode->i_ino;
	else if (!memcmp(de->name,MSDOS_DOTDOT,11)) {
		inum = parent_ino(filp->f_dentry);
	} else {
		struct inode *tmp = fat_iget(sb, i_pos);
		if (tmp) {
			inum = tmp->i_ino;
			iput(tmp);
		} else
			inum = iunique(sb, MSDOS_ROOT_INO);
	}

	if (isvfat) {
		bufuname[j] = 0x0000;
		i = utf8 ? utf8_wcstombs(bufname, bufuname, sizeof(bufname))
			 : uni16_to_x8(bufname, bufuname, uni_xlate, nls_io);
	}

	if (!long_slots||shortnames) {
		if (both)
			bufname[i] = '\0';
		if (filldir(dirent, bufname, i, *furrfu, inum,
			    (de->attr & ATTR_DIR) ? DT_DIR : DT_REG) < 0)
			goto FillFailed;
	} else {
		unsigned char longname[275];
		int long_len = utf8
			? utf8_wcstombs(longname, unicode, sizeof(longname))
			: uni16_to_x8(longname, unicode, uni_xlate,
				      nls_io);
		if (both) {
			memcpy(&longname[long_len+1], bufname, i);
			long_len += i;
		}
		if (filldir(dirent, longname, long_len, *furrfu, inum,
			    (de->attr & ATTR_DIR) ? DT_DIR : DT_REG) < 0)
			goto FillFailed;
	}

RecEnd:
	furrfu = &lpos;
	filp->f_pos = cpos;
	goto GetNew;
EODir:
	filp->f_pos = cpos;
FillFailed:
	if (bh)
		brelse(bh);
	if (unicode) {
		free_page((unsigned long) unicode);
	}
out:
	unlock_kernel();
	return ret;
}

int fat_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
	struct inode *inode = filp->f_dentry->d_inode;
	return fat_readdirx(inode, filp, dirent, filldir, 0, 0);
}

struct fat_ioctl_filldir_callback {
	struct dirent __user *dirent;
	int result;
};

static int fat_ioctl_filldir(void *__buf, const char * name, int name_len,
			     loff_t offset, ino_t ino, unsigned int d_type)
{
	struct fat_ioctl_filldir_callback *buf = __buf;
	struct dirent __user *d1 = buf->dirent;
	struct dirent __user *d2 = d1 + 1;
	int len, slen;
	int dotdir;

	if (buf->result)
		return -EINVAL;
	buf->result++;

	if ((name_len == 1 && name[0] == '.') ||
	    (name_len == 2 && name[0] == '.' && name[1] == '.')) {
		dotdir = 1;
		len = name_len;
	} else {
		dotdir = 0;
		len = strlen(name);
	}
	if (len != name_len) {
		slen = name_len - len;
		if (copy_to_user(d2->d_name, name, len)		||
		    put_user(0, d2->d_name + len)		||
		    put_user(len, &d2->d_reclen)		||
		    put_user(ino, &d2->d_ino)			||
		    put_user(offset, &d2->d_off)		||
		    copy_to_user(d1->d_name, name+len+1, slen)	||
		    put_user(0, d1->d_name+slen)		||
		    put_user(slen, &d1->d_reclen))
			goto efault;
	} else {
		if (put_user(0, d2->d_name)			||
		    put_user(0, &d2->d_reclen)			||
		    copy_to_user(d1->d_name, name, len)		||
		    put_user(0, d1->d_name+len)			||
		    put_user(len, &d1->d_reclen))
			goto efault;
	}
	return 0;
efault:
	buf->result = -EFAULT;
	return -EFAULT;
}

int fat_dir_ioctl(struct inode * inode, struct file * filp,
		  unsigned int cmd, unsigned long arg)
{
	struct fat_ioctl_filldir_callback buf;
	struct dirent __user *d1;
	int ret, shortname, both;

	switch (cmd) {
	case VFAT_IOCTL_READDIR_SHORT:
		shortname = 1;
		both = 1;
		break;
	case VFAT_IOCTL_READDIR_BOTH:
		shortname = 0;
		both = 1;
		break;
	default:
		return -EINVAL;
	}

	d1 = (struct dirent __user *)arg;
	if (!access_ok(VERIFY_WRITE, d1, sizeof(struct dirent[2])))
		return -EFAULT;
	/*
	 * Yes, we don't need this put_user() absolutely. However old
	 * code didn't return the right value. So, app use this value,
	 * in order to check whether it is EOF.
	 */
	if (put_user(0, &d1->d_reclen))
		return -EFAULT;

	buf.dirent = d1;
	buf.result = 0;
	down(&inode->i_sem);
	ret = -ENOENT;
	if (!IS_DEADDIR(inode)) {
		ret = fat_readdirx(inode, filp, &buf, fat_ioctl_filldir,
				   shortname, both);
	}
	up(&inode->i_sem);
	if (ret >= 0)
		ret = buf.result;
	return ret;
}

/* This assumes that size of cluster is above the 32*slots */

int fat_add_entries(struct inode *dir,int slots, struct buffer_head **bh,
		  struct msdos_dir_entry **de, loff_t *i_pos)
{
	struct super_block *sb = dir->i_sb;
	loff_t offset, curr;
	int row;
	struct buffer_head *new_bh;

	offset = curr = 0;
	*bh = NULL;
	row = 0;
	while (fat_get_entry(dir, &curr, bh, de, i_pos) > -1) {
		/* check the maximum size of directory */
		if (curr >= FAT_MAX_DIR_SIZE) {
			brelse(*bh);
			return -ENOSPC;
		}

		if (IS_FREE((*de)->name)) {
			if (++row == slots)
				return offset;
		} else {
			row = 0;
			offset = curr;
		}
	}
	if ((dir->i_ino == MSDOS_ROOT_INO) && (MSDOS_SB(sb)->fat_bits != 32)) 
		return -ENOSPC;
	new_bh = fat_extend_dir(dir);
	if (IS_ERR(new_bh))
		return PTR_ERR(new_bh);
	brelse(new_bh);
	do {
		fat_get_entry(dir, &curr, bh, de, i_pos);
	} while (++row < slots);

	return offset;
}

int fat_new_dir(struct inode *dir, struct inode *parent, int is_vfat)
{
	struct buffer_head *bh;
	struct msdos_dir_entry *de;
	__le16 date, time;

	bh = fat_extend_dir(dir);
	if (IS_ERR(bh))
		return PTR_ERR(bh);

	/* zeroed out, so... */
	fat_date_unix2dos(dir->i_mtime.tv_sec,&time,&date);
	de = (struct msdos_dir_entry*)&bh->b_data[0];
	memcpy(de[0].name,MSDOS_DOT,MSDOS_NAME);
	memcpy(de[1].name,MSDOS_DOTDOT,MSDOS_NAME);
	de[0].attr = de[1].attr = ATTR_DIR;
	de[0].time = de[1].time = time;
	de[0].date = de[1].date = date;
	if (is_vfat) {	/* extra timestamps */
		de[0].ctime = de[1].ctime = time;
		de[0].adate = de[0].cdate =
			de[1].adate = de[1].cdate = date;
	}
	de[0].start = CT_LE_W(MSDOS_I(dir)->i_logstart);
	de[0].starthi = CT_LE_W(MSDOS_I(dir)->i_logstart>>16);
	de[1].start = CT_LE_W(MSDOS_I(parent)->i_logstart);
	de[1].starthi = CT_LE_W(MSDOS_I(parent)->i_logstart>>16);
	mark_buffer_dirty(bh);
	brelse(bh);
	dir->i_atime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
	mark_inode_dirty(dir);

	return 0;
}

static int fat_get_short_entry(struct inode *dir, loff_t *pos,
			       struct buffer_head **bh,
			       struct msdos_dir_entry **de, loff_t *i_pos)
{
	while (fat_get_entry(dir, pos, bh, de, i_pos) >= 0) {
		/* free entry or long name entry or volume label */
		if (!IS_FREE((*de)->name) && !((*de)->attr & ATTR_VOLUME))
			return 0;
	}
	return -ENOENT;
}

/* See if directory is empty */
int fat_dir_empty(struct inode *dir)
{
	struct buffer_head *bh;
	struct msdos_dir_entry *de;
	loff_t cpos, i_pos;
	int result = 0;

	bh = NULL;
	cpos = 0;
	while (fat_get_short_entry(dir, &cpos, &bh, &de, &i_pos) >= 0) {
		if (strncmp(de->name, MSDOS_DOT   , MSDOS_NAME) &&
		    strncmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
			result = -ENOTEMPTY;
			break;
		}
	}
	brelse(bh);
	return result;
}

/*
 * fat_subdirs counts the number of sub-directories of dir. It can be run
 * on directories being created.
 */
int fat_subdirs(struct inode *dir)
{
	struct buffer_head *bh;
	struct msdos_dir_entry *de;
	loff_t cpos, i_pos;
	int count = 0;

	bh = NULL;
	cpos = 0;
	while (fat_get_short_entry(dir, &cpos, &bh, &de, &i_pos) >= 0) {
		if (de->attr & ATTR_DIR)
			count++;
	}
	brelse(bh);
	return count;
}

/*
 * Scans a directory for a given file (name points to its formatted name).
 * Returns an error code or zero.
 */
int fat_scan(struct inode *dir, const unsigned char *name,
	     struct buffer_head **bh, struct msdos_dir_entry **de,
	     loff_t *i_pos)
{
	loff_t cpos;

	*bh = NULL;
	cpos = 0;
	while (fat_get_short_entry(dir, &cpos, bh, de, i_pos) >= 0) {
		if (!strncmp((*de)->name, name, MSDOS_NAME))
			return 0;
	}
	return -ENOENT;
}