295 lines
6.7 KiB
C++
295 lines
6.7 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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public:
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enum Node_type {
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NODE_TYPE_FILE, NODE_TYPE_SYMLINK,
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NODE_TYPE_CHAR_DEVICE, NODE_TYPE_BLOCK_DEVICE
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};
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private:
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Node_type const _node_type;
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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 _node_type;
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char 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 node_type,
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char const *filename)
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:
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Single_vfs_handle(ds, fs, alloc, 0),
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_node_type(node_type),
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_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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if (index == 0) {
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out->fileno = (Genode::addr_t)this;
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switch (_node_type) {
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case NODE_TYPE_FILE: out->type = DIRENT_TYPE_FILE; break;
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case NODE_TYPE_SYMLINK: out->type = DIRENT_TYPE_SYMLINK; break;
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case NODE_TYPE_CHAR_DEVICE: out->type = DIRENT_TYPE_CHARDEV; break;
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case NODE_TYPE_BLOCK_DEVICE: out->type = DIRENT_TYPE_BLOCKDEV; break;
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}
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strncpy(out->name, _filename, sizeof(out->name));
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} else {
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out->type = DIRENT_TYPE_END;
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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, char const *type_name, Xml_node config)
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:
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_node_type(node_type),
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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.mode = STAT_MODE_DIRECTORY;
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} else if (_single_file(path)) {
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switch (_node_type) {
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case NODE_TYPE_FILE: out.mode = STAT_MODE_FILE; break;
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case NODE_TYPE_SYMLINK: out.mode = STAT_MODE_SYMLINK; break;
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case NODE_TYPE_CHAR_DEVICE: out.mode = STAT_MODE_CHARDEV; break;
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case NODE_TYPE_BLOCK_DEVICE: out.mode = STAT_MODE_BLOCKDEV; break;
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}
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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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_node_type, _filename.string());
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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)
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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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