path: root/fs/udf/namei.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * namei.c
 *
 * PURPOSE
 *      Inode name handling routines for the OSTA-UDF(tm) filesystem.
 *
 * COPYRIGHT
 *  (C) 1998-2004 Ben Fennema
 *  (C) 1999-2000 Stelias Computing Inc
 *
 * HISTORY
 *
 *  12/12/98 blf  Created. Split out the lookup code from dir.c
 *  04/19/99 blf  link, mknod, symlink support
 */

#include "udfdecl.h"

#include "udf_i.h"
#include "udf_sb.h"
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/crc-itu-t.h>
#include <linux/exportfs.h>
#include <linux/iversion.h>

static inline int udf_match(int len1, const unsigned char *name1, int len2,
			    const unsigned char *name2)
{
	if (len1 != len2)
		return 0;

	return !memcmp(name1, name2, len1);
}

/**
 * udf_fiiter_find_entry - find entry in given directory.
 *
 * @dir:	directory inode to search in
 * @child:	qstr of the name
 * @iter:	iter to use for searching
 *
 * This function searches in the directory @dir for a file name @child. When
 * found, @iter points to the position in the directory with given entry.
 *
 * Returns 0 on success, < 0 on error (including -ENOENT).
 */
static int udf_fiiter_find_entry(struct inode *dir, const struct qstr *child,
				 struct udf_fileident_iter *iter)
{
	int flen;
	unsigned char *fname = NULL;
	struct super_block *sb = dir->i_sb;
	int isdotdot = child->len == 2 &&
		child->name[0] == '.' && child->name[1] == '.';
	int ret;

	fname = kmalloc(UDF_NAME_LEN, GFP_NOFS);
	if (!fname)
		return -ENOMEM;

	for (ret = udf_fiiter_init(iter, dir, 0);
	     !ret && iter->pos < dir->i_size;
	     ret = udf_fiiter_advance(iter)) {
		if (iter->fi.fileCharacteristics & FID_FILE_CHAR_DELETED) {
			if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNDELETE))
				continue;
		}

		if (iter->fi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) {
			if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNHIDE))
				continue;
		}

		if ((iter->fi.fileCharacteristics & FID_FILE_CHAR_PARENT) &&
		    isdotdot)
			goto out_ok;

		if (!iter->fi.lengthFileIdent)
			continue;

		flen = udf_get_filename(sb, iter->name,
				iter->fi.lengthFileIdent, fname, UDF_NAME_LEN);
		if (flen < 0) {
			ret = flen;
			goto out_err;
		}

		if (udf_match(flen, fname, child->len, child->name))
			goto out_ok;
	}
	if (!ret)
		ret = -ENOENT;

out_err:
	udf_fiiter_release(iter);
out_ok:
	kfree(fname);

	return ret;
}

static struct dentry *udf_lookup(struct inode *dir, struct dentry *dentry,
				 unsigned int flags)
{
	struct inode *inode = NULL;
	struct udf_fileident_iter iter;
	int err;

	if (dentry->d_name.len > UDF_NAME_LEN)
		return ERR_PTR(-ENAMETOOLONG);

	err = udf_fiiter_find_entry(dir, &dentry->d_name, &iter);
	if (err < 0 && err != -ENOENT)
		return ERR_PTR(err);

	if (err == 0) {
		struct kernel_lb_addr loc;

		loc = lelb_to_cpu(iter.fi.icb.extLocation);
		udf_fiiter_release(&iter);

		inode = udf_iget(dir->i_sb, &loc);
		if (IS_ERR(inode))
			return ERR_CAST(inode);
	}

	return d_splice_alias(inode, dentry);
}

static int udf_expand_dir_adinicb(struct inode *inode, udf_pblk_t *block)
{
	udf_pblk_t newblock;
	struct buffer_head *dbh = NULL;
	struct kernel_lb_addr eloc;
	struct extent_position epos;
	uint8_t alloctype;
	struct udf_inode_info *iinfo = UDF_I(inode);
	struct udf_fileident_iter iter;
	uint8_t *impuse;
	int ret;

	if (UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_USE_SHORT_AD))
		alloctype = ICBTAG_FLAG_AD_SHORT;
	else
		alloctype = ICBTAG_FLAG_AD_LONG;

	if (!inode->i_size) {
		iinfo->i_alloc_type = alloctype;
		mark_inode_dirty(inode);
		return 0;
	}

	/* alloc block, and copy data to it */
	*block = udf_new_block(inode->i_sb, inode,
			       iinfo->i_location.partitionReferenceNum,
			       iinfo->i_location.logicalBlockNum, &ret);
	if (!(*block))
		return ret;
	newblock = udf_get_pblock(inode->i_sb, *block,
				  iinfo->i_location.partitionReferenceNum,
				0);
	if (newblock == 0xffffffff)
		return -EFSCORRUPTED;
	dbh = sb_getblk(inode->i_sb, newblock);
	if (!dbh)
		return -ENOMEM;
	lock_buffer(dbh);
	memcpy(dbh->b_data, iinfo->i_data, inode->i_size);
	memset(dbh->b_data + inode->i_size, 0,
	       inode->i_sb->s_blocksize - inode->i_size);
	set_buffer_uptodate(dbh);
	unlock_buffer(dbh);

	/* Drop inline data, add block instead */
	iinfo->i_alloc_type = alloctype;
	memset(iinfo->i_data + iinfo->i_