/* * \brief File system that hosts a single node * \author Norman Feske * \date 2014-04-07 */ /* * Copyright (C) 2014-2017 Genode Labs GmbH * * This file is part of the Genode OS framework, which is distributed * under the terms of the GNU Affero General Public License version 3. */ #ifndef _INCLUDE__VFS__SINGLE_FILE_SYSTEM_H_ #define _INCLUDE__VFS__SINGLE_FILE_SYSTEM_H_ #include #include namespace Vfs { class Single_file_system; } class Vfs::Single_file_system : public File_system { private: Node_type const _type; Node_rwx const _rwx; typedef String<64> Filename; Filename _filename { }; protected: struct Single_vfs_handle : Vfs_handle { using Vfs_handle::Vfs_handle; virtual Read_result read(Byte_range_ptr const &, size_t &out_count) = 0; virtual Write_result write(Const_byte_range_ptr const &, size_t &out_count) = 0; virtual Sync_result sync() { return SYNC_OK; } virtual bool read_ready() const = 0; virtual bool write_ready() const = 0; virtual bool notify_read_ready() { return true; } }; struct Single_vfs_dir_handle : Single_vfs_handle { private: Node_type const _type; Node_rwx const _rwx; Filename const &_filename; /* * Noncopyable */ Single_vfs_dir_handle(Single_vfs_dir_handle const &); Single_vfs_dir_handle &operator = (Single_vfs_dir_handle const &); public: Single_vfs_dir_handle(Directory_service &ds, File_io_service &fs, Genode::Allocator &alloc, Node_type type, Node_rwx rwx, Filename const &filename) : Single_vfs_handle(ds, fs, alloc, 0), _type(type), _rwx(rwx), _filename(filename) { } Read_result read(Byte_range_ptr const &dst, size_t &out_count) override { out_count = 0; if (dst.num_bytes < sizeof(Dirent)) return READ_ERR_INVALID; file_size index = seek() / sizeof(Dirent); Dirent &out = *(Dirent*)dst.start; auto dirent_type = [&] () { switch (_type) { case Node_type::DIRECTORY: return Dirent_type::DIRECTORY; case Node_type::SYMLINK: return Dirent_type::SYMLINK; case Node_type::CONTINUOUS_FILE: return Dirent_type::CONTINUOUS_FILE; case Node_type::TRANSACTIONAL_FILE: return Dirent_type::TRANSACTIONAL_FILE; } return Dirent_type::END; }; if (index == 0) { out = { .fileno = (Genode::addr_t)this, .type = dirent_type(), .rwx = _rwx, .name = { _filename.string() } }; } else { out = { .fileno = (Genode::addr_t)this, .type = Dirent_type::END, .rwx = { }, .name = { } }; } out_count = sizeof(Dirent); return READ_OK; } Write_result write(Const_byte_range_ptr const &, size_t &) override { return WRITE_ERR_INVALID; } bool read_ready() const override { return true; } bool write_ready() const override { return true; } }; bool _root(const char *path) { return (strcmp(path, "") == 0) || (strcmp(path, "/") == 0); } bool _single_file(const char *path) { return (strlen(path) == (strlen(_filename.string()) + 1)) && (strcmp(&path[1], _filename.string()) == 0); } public: Single_file_system(Node_type node_type, char const *type_name, Node_rwx rwx, Xml_node config) : _type(node_type), _rwx(rwx), _filename(config.attribute_value("name", Filename(type_name))) { } /********************************* ** Directory-service interface ** *********************************/ Dataspace_capability dataspace(char const *) override { return Dataspace_capability(); } void release(char const *, Dataspace_capability) override { } Stat_result stat(char const *path, Stat &out) override { out = Stat { }; out.device = (Genode::addr_t)this; if (_root(path)) { out.type = Node_type::DIRECTORY; } else if (_single_file(path)) { out.type = _type; out.rwx = _rwx; out.inode = 1; } else { return STAT_ERR_NO_ENTRY; } return STAT_OK; } file_size num_dirent(char const *path) override { if (_root(path)) return 1; else return 0; } bool directory(char const *path) override { if (_root(path)) return true; return false; } char const *leaf_path(char const *path) override { return _single_file(path) ? path : 0; } Opendir_result opendir(char const *path, bool create, Vfs_handle **out_handle, Allocator &alloc) override { if (!_root(path)) return OPENDIR_ERR_LOOKUP_FAILED; if (create) return OPENDIR_ERR_PERMISSION_DENIED; try { *out_handle = new (alloc) Single_vfs_dir_handle(*this, *this, alloc, _type, _rwx, _filename); return OPENDIR_OK; } catch (Genode::Out_of_ram) { return OPENDIR_ERR_OUT_OF_RAM; } catch (Genode::Out_of_caps) { return OPENDIR_ERR_OUT_OF_CAPS; } } void close(Vfs_handle *handle) override { if (handle && (&handle->ds() == this)) destroy(handle->alloc(), handle); } Unlink_result unlink(char const *path) override { if (_single_file(path)) return UNLINK_ERR_NO_PERM; return UNLINK_ERR_NO_ENTRY; } Rename_result rename(char const *from, char const *to) override { if (_single_file(from) || _single_file(to)) return RENAME_ERR_NO_PERM; return RENAME_ERR_NO_ENTRY; } /******************************** ** File I/O service interface ** ********************************/ Read_result complete_read(Vfs_handle *vfs_handle, Byte_range_ptr const &dst, size_t &out_count) override { Single_vfs_handle *handle = static_cast(vfs_handle); if (handle) return handle->read(dst, out_count); return READ_ERR_INVALID; } Write_result write(Vfs_handle *vfs_handle, Const_byte_range_ptr const &src, size_t &out_count) override { Single_vfs_handle *handle = static_cast(vfs_handle); if (handle) return handle->write(src, out_count); return WRITE_ERR_INVALID; } bool read_ready(Vfs_handle const &vfs_handle) const override { Single_vfs_handle const &handle = static_cast(vfs_handle); return handle.read_ready(); } bool write_ready(Vfs_handle const &vfs_handle) const override { Single_vfs_handle const &handle = static_cast(vfs_handle); return handle.write_ready(); } bool notify_read_ready(Vfs_handle *vfs_handle) override { Single_vfs_handle *handle = static_cast(vfs_handle); if (handle) return handle->notify_read_ready(); return false; } Ftruncate_result ftruncate(Vfs_handle *, file_size) override { return FTRUNCATE_ERR_NO_PERM; } Sync_result complete_sync(Vfs_handle *vfs_handle) override { Single_vfs_handle *handle = static_cast(vfs_handle); if (handle) return handle->sync(); return SYNC_ERR_INVALID; } }; #endif /* _INCLUDE__VFS__SINGLE_FILE_SYSTEM_H_ */