encfs/encfs/FileNode.h
2017-08-09 17:36:20 +02:00

115 lines
3.4 KiB
C++

/*****************************************************************************
* Author: Valient Gough <vgough@pobox.com>
*
*****************************************************************************
* Copyright (c) 2003, Valient Gough
*
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by the
* Free Software Foundation, either version 3 of the License, or (at your
* option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _FileNode_incl_
#define _FileNode_incl_
#include <atomic>
#include <inttypes.h>
#include <memory>
#include <pthread.h>
#include <stdint.h>
#include <string>
#include <sys/types.h>
#include "CipherKey.h"
#include "FSConfig.h"
#include "FileUtils.h"
#include "encfs.h"
#define CANARY_OK 0x46040975
#define CANARY_RELEASED 0x70c5610d
#define CANARY_DESTROYED 0x52cdad90
namespace encfs {
class Cipher;
class DirNode;
class FileIO;
class FileNode {
public:
FileNode(DirNode *parent, const FSConfigPtr &cfg, const char *plaintextName,
const char *cipherName, uint64_t fuseFh);
~FileNode();
// Use an atomic type. The canary is accessed without holding any
// locks.
std::atomic<std::uint32_t> canary;
// FUSE file handle that is passed to the kernel
uint64_t fuseFh;
const char *plaintextName() const;
const char *cipherName() const;
// directory portion of plaintextName
std::string plaintextParent() const;
// if setIVFirst is true, then the IV is changed before the name is changed
// (default). The reverse is also supported for special cases..
bool setName(const char *plaintextName, const char *cipherName, uint64_t iv,
bool setIVFirst = true);
// create node
// If uid/gid are not 0, then chown is used change ownership as specified
int mknod(mode_t mode, dev_t rdev, uid_t uid = 0, gid_t gid = 0);
// Returns < 0 on error (-errno), file descriptor on success.
int open(int flags) const;
// getAttr returns 0 on success, -errno on failure
int getAttr(struct stat *stbuf) const;
off_t getSize() const;
ssize_t read(off_t offset, unsigned char *data, size_t size) const;
ssize_t write(off_t offset, unsigned char *data, size_t size);
// truncate the file to a particular size
int truncate(off_t size);
// datasync or full sync
int sync(bool dataSync);
private:
// doing locking at the FileNode level isn't as efficient as at the
// lowest level of RawFileIO, since that means locks are held longer
// (held during CPU intensive crypto operations!). However it makes it
// easier to avoid any race conditions with operations such as
// truncate() which may result in multiple calls down to the FileIO
// level.
mutable pthread_mutex_t mutex;
FSConfigPtr fsConfig;
std::shared_ptr<FileIO> io;
std::string _pname; // plaintext name
std::string _cname; // encrypted name
DirNode *parent;
private:
FileNode(const FileNode &src);
FileNode &operator=(const FileNode &src);
};
} // namespace encfs
#endif