readdir.c

Linux内核自带的cifs模块

	if (pos_in_buf >= cifsFile->srch_inf.entries_in_buffer) {
		cFYI(1, ("can not return entries pos_in_buf beyond last"));
		*num_to_ret = 0;
	} else
		*num_to_ret = cifsFile->srch_inf.entries_in_buffer - pos_in_buf;

	return rc;
}

/* inode num, inode type and filename returned */
static int cifs_get_name_from_search_buf(struct qstr *pqst,
	char *current_entry, __u16 level, unsigned int unicode,
	struct cifs_sb_info *cifs_sb, int max_len, ino_t *pinum)
{
	int rc = 0;
	unsigned int len = 0;
	char *filename;
	struct nls_table *nlt = cifs_sb->local_nls;

	*pinum = 0;

	if (level == SMB_FIND_FILE_UNIX) {
		FILE_UNIX_INFO *pFindData = (FILE_UNIX_INFO *)current_entry;

		filename = &pFindData->FileName[0];
		if (unicode) {
			len = cifs_unicode_bytelen(filename);
		} else {
			/* BB should we make this strnlen of PATH_MAX? */
			len = strnlen(filename, PATH_MAX);
		}

		/* BB fixme - hash low and high 32 bits if not 64 bit arch BB */
		if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)
			*pinum = pFindData->UniqueId;
	} else if (level == SMB_FIND_FILE_DIRECTORY_INFO) {
		FILE_DIRECTORY_INFO *pFindData =
			(FILE_DIRECTORY_INFO *)current_entry;
		filename = &pFindData->FileName[0];
		len = le32_to_cpu(pFindData->FileNameLength);
	} else if (level == SMB_FIND_FILE_FULL_DIRECTORY_INFO) {
		FILE_FULL_DIRECTORY_INFO *pFindData =
			(FILE_FULL_DIRECTORY_INFO *)current_entry;
		filename = &pFindData->FileName[0];
		len = le32_to_cpu(pFindData->FileNameLength);
	} else if (level == SMB_FIND_FILE_ID_FULL_DIR_INFO) {
		SEARCH_ID_FULL_DIR_INFO *pFindData =
			(SEARCH_ID_FULL_DIR_INFO *)current_entry;
		filename = &pFindData->FileName[0];
		len = le32_to_cpu(pFindData->FileNameLength);
		*pinum = pFindData->UniqueId;
	} else if (level == SMB_FIND_FILE_BOTH_DIRECTORY_INFO) {
		FILE_BOTH_DIRECTORY_INFO *pFindData =
			(FILE_BOTH_DIRECTORY_INFO *)current_entry;
		filename = &pFindData->FileName[0];
		len = le32_to_cpu(pFindData->FileNameLength);
	} else if (level == SMB_FIND_FILE_INFO_STANDARD) {
		FIND_FILE_STANDARD_INFO * pFindData =
			(FIND_FILE_STANDARD_INFO *)current_entry;
		filename = &pFindData->FileName[0];
		/* one byte length, no name conversion */
		len = (unsigned int)pFindData->FileNameLength;
	} else {
		cFYI(1, ("Unknown findfirst level %d", level));
		return -EINVAL;
	}

	if (len > max_len) {
		cERROR(1, ("bad search response length %d past smb end", len));
		return -EINVAL;
	}

	if (unicode) {
		/* BB fixme - test with long names */
		/* Note converted filename can be longer than in unicode */
		if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR)
			pqst->len = cifs_convertUCSpath((char *)pqst->name,
					(__le16 *)filename, len/2, nlt);
		else
			pqst->len = cifs_strfromUCS_le((char *)pqst->name,
					(__le16 *)filename, len/2, nlt);
	} else {
		pqst->name = filename;
		pqst->len = len;
	}
	pqst->hash = full_name_hash(pqst->name, pqst->len);
/*	cFYI(1, ("filldir on %s",pqst->name));  */
	return rc;
}

static int cifs_filldir(char *pfindEntry, struct file *file,
	filldir_t filldir, void *direntry, char *scratch_buf, int max_len)
{
	int rc = 0;
	struct qstr qstring;
	struct cifsFileInfo *pCifsF;
	unsigned obj_type;
	ino_t  inum;
	struct cifs_sb_info *cifs_sb;
	struct inode *tmp_inode;
	struct dentry *tmp_dentry;

	/* get filename and len into qstring */
	/* get dentry */
	/* decide whether to create and populate ionde */
	if ((direntry == NULL) || (file == NULL))
		return -EINVAL;

	pCifsF = file->private_data;

	if ((scratch_buf == NULL) || (pfindEntry == NULL) || (pCifsF == NULL))
		return -ENOENT;

	rc = cifs_entry_is_dot(pfindEntry, pCifsF);
	/* skip . and .. since we added them first */
	if (rc != 0)
		return 0;

#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 20)
	cifs_sb = CIFS_SB(file->f_dentry->d_sb);
#else
	cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
#endif

	qstring.name = scratch_buf;
	rc = cifs_get_name_from_search_buf(&qstring, pfindEntry,
			pCifsF->srch_inf.info_level,
			pCifsF->srch_inf.unicode, cifs_sb,
			max_len,
			&inum /* returned */);

	if (rc)
		return rc;

	rc = construct_dentry(&qstring, file, &tmp_inode, &tmp_dentry);
	if ((tmp_inode == NULL) || (tmp_dentry == NULL))
		return -ENOMEM;

	if (rc) {
		/* inode created, we need to hash it with right inode number */
		if (inum != 0) {
			/* BB fixme - hash the 2 32 quantities bits together if
			 *  necessary BB */
			tmp_inode->i_ino = inum;
		}
		insert_inode_hash(tmp_inode);
	}

	/* we pass in rc below, indicating whether it is a new inode,
	   so we can figure out whether to invalidate the inode cached
	   data if the file has changed */
	if (pCifsF->srch_inf.info_level == SMB_FIND_FILE_UNIX)
		unix_fill_in_inode(tmp_inode,
				   (FILE_UNIX_INFO *)pfindEntry,
				   &obj_type, rc);
	else if (pCifsF->srch_inf.info_level == SMB_FIND_FILE_INFO_STANDARD)
		fill_in_inode(tmp_inode, 0 /* old level 1 buffer type */,
				pfindEntry, &obj_type, rc);
	else
		fill_in_inode(tmp_inode, 1 /* NT */, pfindEntry, &obj_type, rc);

	if (rc) /* new inode - needs to be tied to dentry */ {
		d_instantiate(tmp_dentry, tmp_inode);
		if (rc == 2)
			d_rehash(tmp_dentry);
	}


	rc = filldir(direntry, qstring.name, qstring.len, file->f_pos,
		     tmp_inode->i_ino, obj_type);
	if (rc) {
		cFYI(1, ("filldir rc = %d", rc));
		/* we can not return filldir errors to the caller
		since they are "normal" when the stat blocksize
		is too small - we return remapped error instead */
		rc = -EOVERFLOW;
	}

	dput(tmp_dentry);
	return rc;
}

static int cifs_save_resume_key(const char *current_entry,
	struct cifsFileInfo *cifsFile)
{
	int rc = 0;
	unsigned int len = 0;
	__u16 level;
	char *filename;

	if ((cifsFile == NULL) || (current_entry == NULL))
		return -EINVAL;

	level = cifsFile->srch_inf.info_level;

	if (level == SMB_FIND_FILE_UNIX) {
		FILE_UNIX_INFO * pFindData = (FILE_UNIX_INFO *)current_entry;

		filename = &pFindData->FileName[0];
		if (cifsFile->srch_inf.unicode) {
			len = cifs_unicode_bytelen(filename);
		} else {
			/* BB should we make this strnlen of PATH_MAX? */
			len = strnlen(filename, PATH_MAX);
		}
		cifsFile->srch_inf.resume_key = pFindData->ResumeKey;
	} else if (level == SMB_FIND_FILE_DIRECTORY_INFO) {
		FILE_DIRECTORY_INFO *pFindData =
			(FILE_DIRECTORY_INFO *)current_entry;
		filename = &pFindData->FileName[0];
		len = le32_to_cpu(pFindData->FileNameLength);
		cifsFile->srch_inf.resume_key = pFindData->FileIndex;
	} else if (level == SMB_FIND_FILE_FULL_DIRECTORY_INFO) {
		FILE_FULL_DIRECTORY_INFO *pFindData =
			(FILE_FULL_DIRECTORY_INFO *)current_entry;
		filename = &pFindData->FileName[0];
		len = le32_to_cpu(pFindData->FileNameLength);
		cifsFile->srch_inf.resume_key = pFindData->FileIndex;
	} else if (level == SMB_FIND_FILE_ID_FULL_DIR_INFO) {
		SEARCH_ID_FULL_DIR_INFO *pFindData =
			(SEARCH_ID_FULL_DIR_INFO *)current_entry;
		filename = &pFindData->FileName[0];
		len = le32_to_cpu(pFindData->FileNameLength);
		cifsFile->srch_inf.resume_key = pFindData->FileIndex;
	} else if (level == SMB_FIND_FILE_BOTH_DIRECTORY_INFO) {
		FILE_BOTH_DIRECTORY_INFO *pFindData =
			(FILE_BOTH_DIRECTORY_INFO *)current_entry;
		filename = &pFindData->FileName[0];
		len = le32_to_cpu(pFindData->FileNameLength);
		cifsFile->srch_inf.resume_key = pFindData->FileIndex;
	} else if (level == SMB_FIND_FILE_INFO_STANDARD) {
		FIND_FILE_STANDARD_INFO *pFindData =
			(FIND_FILE_STANDARD_INFO *)current_entry;
		filename = &pFindData->FileName[0];
		/* one byte length, no name conversion */
		len = (unsigned int)pFindData->FileNameLength;
		cifsFile->srch_inf.resume_key = pFindData->ResumeKey;
	} else {
		cFYI(1, ("Unknown findfirst level %d", level));
		return -EINVAL;
	}
	cifsFile->srch_inf.resume_name_len = len;
	cifsFile->srch_inf.presume_name = filename;
	return rc;
}

int cifs_readdir(struct file *file, void *direntry, filldir_t filldir)
{
	int rc = 0;
	int xid, i;
	struct cifs_sb_info *cifs_sb;
	struct cifsTconInfo *pTcon;
	struct cifsFileInfo *cifsFile = NULL;
	char *current_entry;
	int num_to_fill = 0;
	char *tmp_buf = NULL;
	char *end_of_smb;
	int max_len;

	xid = GetXid();

#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 20)
	cifs_sb = CIFS_SB(file->f_dentry->d_sb);
	pTcon = cifs_sb->tcon;
	if (pTcon == NULL)
		return -EINVAL;

	switch ((int) file->f_pos) {
	case 0:
		if (filldir(direntry, ".", 1, file->f_pos,
		     file->f_dentry->d_inode->i_ino, DT_DIR) < 0) {
			cERROR(1, ("Filldir for current dir failed"));
			rc = -ENOMEM;
			break;
		}
		file->f_pos++;
	case 1:
		if (filldir(direntry, "..", 2, file->f_pos,
		     file->f_dentry->d_parent->d_inode->i_ino, DT_DIR) < 0) {
#else
	cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
	pTcon = cifs_sb->tcon;
	if (pTcon == NULL)
		return -EINVAL;

	switch ((int) file->f_pos) {
	case 0:
		if (filldir(direntry, ".", 1, file->f_pos,
		     file->f_path.dentry->d_inode->i_ino, DT_DIR) < 0) {
			cERROR(1, ("Filldir for current dir failed"));
			rc = -ENOMEM;
			break;
		}
		file->f_pos++;
	case 1:
		if (filldir(direntry, "..", 2, file->f_pos,
		     file->f_path.dentry->d_parent->d_inode->i_ino, DT_DIR) < 0) {
#endif
			cERROR(1, ("Filldir for parent dir failed"));
			rc = -ENOMEM;
			break;
		}
		file->f_pos++;
	default:
		/* 1) If search is active,
			is in current search buffer?
			if it before then restart search
			if after then keep searching till find it */

		if (file->private_data == NULL) {
			rc = initiate_cifs_search(xid, file);
			cFYI(1, ("initiate cifs search rc %d", rc));
			if (rc) {
				FreeXid(xid);
				return rc;
			}
		}
		if (file->private_data == NULL) {
			rc = -EINVAL;
			FreeXid(xid);
			return rc;
		}
		cifsFile = file->private_data;
		if (cifsFile->srch_inf.endOfSearch) {
			if (cifsFile->srch_inf.emptyDir) {
				cFYI(1, ("End of search, empty dir"));
				rc = 0;
				break;
			}
		} /* else {
			cifsFile->invalidHandle = TRUE;
			CIFSFindClose(xid, pTcon, cifsFile->netfid);
		}
		kfree(cifsFile->search_resume_name);
		cifsFile->search_resume_name = NULL; */

		rc = find_cifs_entry(xid, pTcon, file,
				&current_entry, &num_to_fill);
		if (rc) {
			cFYI(1, ("fce error %d", rc));
			goto rddir2_exit;
		} else if (current_entry != NULL) {
			cFYI(1, ("entry %lld found", file->f_pos));
		} else {
			cFYI(1, ("could not find entry"));
			goto rddir2_exit;
		}
		cFYI(1, ("loop through %d times filling dir for net buf %p",
			num_to_fill, cifsFile->srch_inf.ntwrk_buf_start));
		max_len = smbCalcSize((struct smb_hdr *)
				cifsFile->srch_inf.ntwrk_buf_start);
		end_of_smb = cifsFile->srch_inf.ntwrk_buf_start + max_len;

		/* To be safe - for UCS to UTF-8 with strings loaded
		with the rare long characters alloc more to account for
		such multibyte target UTF-8 characters. cifs_unicode.c,
		which actually does the conversion, has the same limit */
		tmp_buf = kmalloc((2 * NAME_MAX) + 4, GFP_KERNEL);
		for (i = 0; (i < num_to_fill) && (rc == 0); i++) {
			if (current_entry == NULL) {
				/* evaluate whether this case is an error */
				cERROR(1, ("past SMB end,  num to fill %d i %d",
					  num_to_fill, i));
				break;
			}
			/* if buggy server returns . and .. late do
			we want to check for that here? */
			rc = cifs_filldir(current_entry, file,
					filldir, direntry, tmp_buf, max_len);
			if (rc == -EOVERFLOW) {
				rc = 0;
				break;
			}

			file->f_pos++;
			if (file->f_pos ==
				cifsFile->srch_inf.index_of_last_entry) {
				cFYI(1, ("last entry in buf at pos %lld %s",
					file->f_pos, tmp_buf));
				cifs_save_resume_key(current_entry, cifsFile);
				break;
			} else
				current_entry =
					nxt_dir_entry(current_entry, end_of_smb,
						cifsFile->srch_inf.info_level);
		}
		kfree(tmp_buf);
		break;
	} /* end switch */

rddir2_exit:
	FreeXid(xid);
	return rc;
}