| // Copyright 2019 The Fuchsia Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef SRC_STORAGE_FVM_HOST_FILE_WRAPPER_H_ |
| #define SRC_STORAGE_FVM_HOST_FILE_WRAPPER_H_ |
| |
| #include <fcntl.h> |
| #include <unistd.h> |
| #include <zircon/types.h> |
| |
| #include <memory> |
| #include <utility> |
| |
| #include <fbl/macros.h> |
| #include <fbl/unique_fd.h> |
| |
| // Namespace these classes to prevent collisions with minfs's FileWrapper. |
| namespace fvm::host { |
| |
| // FileWrapper exposes a file-like interface to abstract away the actual |
| // file system implementation. Interface matches POSIX functions of the same |
| // name. |
| class FileWrapper { |
| public: |
| virtual ~FileWrapper() {} |
| virtual ssize_t Read(void* buffer, size_t count) = 0; |
| virtual ssize_t Write(const void* buffer, size_t count) = 0; |
| virtual ssize_t Seek(off_t offset, int whence) = 0; |
| virtual ssize_t Size() = 0; |
| virtual ssize_t Tell() = 0; |
| |
| // Truncates file to |size| bytes. |
| // Returns ZX_OK on success, ZX_ERR_NOT_SUPPORTED if truncate is |
| // not supported, or -1 if truncate operation fails. |
| virtual zx_status_t Truncate(size_t size) = 0; |
| |
| // Flushes pending data. |
| virtual zx_status_t Sync() = 0; |
| }; |
| |
| // Implementation of FileWrapper that wraps a raw file descripter. |
| // File descriptor is expected to refer to a file that is compatible |
| // with standard POSIX file functions, e.g. read, write, ftruncate, etc. |
| class FdWrapper : public FileWrapper { |
| public: |
| FdWrapper(int fd) : fd_(fd) {} |
| |
| ssize_t Read(void* buffer, size_t count) override; |
| ssize_t Write(const void* buffer, size_t count) override; |
| ssize_t Seek(off_t offset, int whence) override; |
| ssize_t Size() override; |
| ssize_t Tell() override; |
| zx_status_t Truncate(size_t size) override; |
| zx_status_t Sync() override; |
| |
| DISALLOW_COPY_AND_ASSIGN_ALLOW_MOVE(FdWrapper); |
| |
| private: |
| int fd_; |
| }; |
| |
| // Implementation of FileWrapper that takes ownership of a unique_fd. |
| // File descriptor is expected to refer to a file that is compatible |
| // with standard POSIX file functions, e.g. read, write, ftruncate, etc. |
| class UniqueFdWrapper : public FileWrapper { |
| public: |
| static zx_status_t Open(const char* path, int flags, mode_t mode, |
| std::unique_ptr<UniqueFdWrapper>* out); |
| UniqueFdWrapper(fbl::unique_fd fd) : fd_(std::move(fd)) {} |
| |
| ssize_t Read(void* buffer, size_t count) override; |
| ssize_t Write(const void* buffer, size_t count) override; |
| ssize_t Seek(off_t offset, int whence) override; |
| ssize_t Size() override; |
| ssize_t Tell() override; |
| zx_status_t Truncate(size_t size) override; |
| zx_status_t Sync() override; |
| |
| DISALLOW_COPY_AND_ASSIGN_ALLOW_MOVE(UniqueFdWrapper); |
| |
| private: |
| fbl::unique_fd fd_; |
| }; |
| |
| // Implements a FileWrapper that uses unique_fd for file access, but doesn't |
| // support truncate operation. Used for writing directly to a partition that |
| // has a fixed size. |
| class BlockDeviceFdWrapper : public UniqueFdWrapper { |
| public: |
| static zx_status_t Open(const char* path, int flags, mode_t mode, |
| std::unique_ptr<BlockDeviceFdWrapper>* out); |
| explicit BlockDeviceFdWrapper(fbl::unique_fd fd) : UniqueFdWrapper(std::move(fd)) {} |
| zx_status_t Truncate(size_t size) override; |
| |
| DISALLOW_COPY_AND_ASSIGN_ALLOW_MOVE(BlockDeviceFdWrapper); |
| }; |
| |
| } // namespace fvm::host |
| |
| #endif // SRC_STORAGE_FVM_HOST_FILE_WRAPPER_H_ |