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