632 lines
17 KiB
C++
632 lines
17 KiB
C++
/*
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* \brief Adapter from Genode 'File_system' session to VFS
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* \author Norman Feske
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* \date 2011-02-17
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*/
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/*
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* Copyright (C) 2012-2014 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 General Public License version 2.
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*/
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#ifndef _INCLUDE__VFS__FS_FILE_SYSTEM_H_
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#define _INCLUDE__VFS__FS_FILE_SYSTEM_H_
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/* Genode includes */
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#include <base/allocator_avl.h>
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#include <file_system_session/connection.h>
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namespace Vfs { class Fs_file_system; }
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class Vfs::Fs_file_system : public File_system
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{
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enum { verbose = false };
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private:
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/*
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* Lock used to serialize the interaction with the packet stream of the
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* file-system session.
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*
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* XXX Once, we change the VFS file-system interface to use
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* asynchronous read/write operations, we can possibly remove it.
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*/
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Lock _lock;
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Genode::Allocator_avl _fs_packet_alloc;
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struct Label
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{
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enum { LABEL_MAX_LEN = 64 };
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char string[LABEL_MAX_LEN];
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Label(Xml_node config)
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{
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string[0] = 0;
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try { config.attribute("label").value(string, sizeof(string)); }
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catch (...) { }
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}
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} _label;
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::File_system::Connection _fs;
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class Fs_vfs_handle : public Vfs_handle
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{
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private:
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::File_system::File_handle const _handle;
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public:
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Fs_vfs_handle(File_system &fs, int status_flags,
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::File_system::File_handle handle)
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: Vfs_handle(fs, fs, status_flags), _handle(handle)
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{ }
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~Fs_vfs_handle()
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{
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Fs_file_system &fs = static_cast<Fs_file_system &>(ds());
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fs._fs.close(_handle);
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}
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::File_system::File_handle file_handle() const { return _handle; }
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};
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/**
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* Helper for managing the lifetime of temporary open node handles
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*/
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struct Fs_handle_guard
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{
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::File_system::Session &_fs;
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::File_system::Node_handle _handle;
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Fs_handle_guard(::File_system::Session &fs,
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::File_system::Node_handle handle)
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: _fs(fs), _handle(handle) { }
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~Fs_handle_guard() { _fs.close(_handle); }
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};
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file_size _read(::File_system::Node_handle node_handle, void *buf,
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file_size const count, file_size const seek_offset)
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{
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::File_system::Session::Tx::Source &source = *_fs.tx();
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file_size const max_packet_size = source.bulk_buffer_size() / 2;
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file_size const clipped_count = min(max_packet_size, count);
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::File_system::Packet_descriptor const
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packet_in(source.alloc_packet(clipped_count),
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0,
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node_handle,
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::File_system::Packet_descriptor::READ,
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clipped_count,
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seek_offset);
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/* pass packet to server side */
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source.submit_packet(packet_in);
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/* obtain result packet descriptor with updated status info */
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::File_system::Packet_descriptor const
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packet_out = source.get_acked_packet();
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file_size const read_num_bytes = min(packet_out.length(), count);
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memcpy(buf, source.packet_content(packet_out), read_num_bytes);
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/*
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* XXX check if acked packet belongs to request,
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* needed for thread safety
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*/
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source.release_packet(packet_out);
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return read_num_bytes;
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}
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file_size _write(::File_system::Node_handle node_handle,
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const char *buf, file_size count, file_size seek_offset)
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{
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::File_system::Session::Tx::Source &source = *_fs.tx();
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file_size const max_packet_size = source.bulk_buffer_size() / 2;
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count = min(max_packet_size, count);
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::File_system::Packet_descriptor
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packet(source.alloc_packet(count),
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0,
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node_handle,
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::File_system::Packet_descriptor::WRITE,
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count,
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seek_offset);
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memcpy(source.packet_content(packet), buf, count);
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/* pass packet to server side */
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source.submit_packet(packet);
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source.get_acked_packet();
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/*
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* XXX check if acked packet belongs to request,
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* needed for thread safety
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*/
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source.release_packet(packet);
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return count;
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}
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public:
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/*
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* XXX read label from config
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*/
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Fs_file_system(Xml_node config)
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:
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_fs_packet_alloc(env()->heap()),
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_label(config),
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_fs(_fs_packet_alloc, 128*1024, _label.string)
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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 *path) override
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{
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Lock::Guard guard(_lock);
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Absolute_path dir_path(path);
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dir_path.strip_last_element();
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Absolute_path file_name(path);
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file_name.keep_only_last_element();
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Ram_dataspace_capability ds_cap;
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char *local_addr = 0;
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try {
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::File_system::Dir_handle dir = _fs.dir(dir_path.base(),
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false);
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Fs_handle_guard dir_guard(_fs, dir);
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::File_system::File_handle file =
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_fs.file(dir, file_name.base() + 1,
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::File_system::READ_ONLY, false);
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Fs_handle_guard file_guard(_fs, file);
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::File_system::Status status = _fs.status(file);
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Ram_dataspace_capability ds_cap =
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env()->ram_session()->alloc(status.size);
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local_addr = env()->rm_session()->attach(ds_cap);
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::File_system::Session::Tx::Source &source = *_fs.tx();
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file_size const max_packet_size = source.bulk_buffer_size() / 2;
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for (file_size seek_offset = 0; seek_offset < status.size;
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seek_offset += max_packet_size) {
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file_size const count = min(max_packet_size, status.size -
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seek_offset);
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::File_system::Packet_descriptor
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packet(source.alloc_packet(count),
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0,
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file,
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::File_system::Packet_descriptor::READ,
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count,
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seek_offset);
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/* pass packet to server side */
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source.submit_packet(packet);
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source.get_acked_packet();
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memcpy(local_addr + seek_offset, source.packet_content(packet), count);
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/*
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* XXX check if acked packet belongs to request,
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* needed for thread safety
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*/
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source.release_packet(packet);
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}
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env()->rm_session()->detach(local_addr);
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return ds_cap;
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} catch(...) {
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env()->rm_session()->detach(local_addr);
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env()->ram_session()->free(ds_cap);
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return Dataspace_capability();
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}
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}
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void release(char const *path, Dataspace_capability ds_cap) override
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{
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env()->ram_session()->free(static_cap_cast<Genode::Ram_dataspace>(ds_cap));
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}
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Stat_result stat(char const *path, Stat &out) override
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{
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::File_system::Status status;
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try {
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::File_system::Node_handle node = _fs.node(path);
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Fs_handle_guard node_guard(_fs, node);
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status = _fs.status(node);
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} catch (...) {
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if (verbose)
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PDBG("stat failed for path '%s'", path);
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return STAT_ERR_NO_ENTRY;
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}
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memset(&out, 0, sizeof(out));
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out.size = status.size;
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out.mode = STAT_MODE_FILE | 0777;
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if (status.is_symlink())
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out.mode = STAT_MODE_SYMLINK | 0777;
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if (status.is_directory())
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out.mode = STAT_MODE_DIRECTORY | 0777;
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out.uid = 0;
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out.gid = 0;
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return STAT_OK;
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}
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Dirent_result dirent(char const *path, file_offset index, Dirent &out) override
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{
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Lock::Guard guard(_lock);
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::File_system::Session::Tx::Source &source = *_fs.tx();
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if (strcmp(path, "") == 0)
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path = "/";
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::File_system::Dir_handle dir_handle = _fs.dir(path, false);
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Fs_handle_guard dir_guard(_fs, dir_handle);
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enum { DIRENT_SIZE = sizeof(::File_system::Directory_entry) };
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::File_system::Packet_descriptor
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packet(source.alloc_packet(DIRENT_SIZE),
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0,
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dir_handle,
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::File_system::Packet_descriptor::READ,
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DIRENT_SIZE,
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index*DIRENT_SIZE);
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/* pass packet to server side */
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source.submit_packet(packet);
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source.get_acked_packet();
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/*
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* XXX check if acked packet belongs to request,
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* needed for thread safety
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*/
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typedef ::File_system::Directory_entry Directory_entry;
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/* copy-out payload into destination buffer */
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Directory_entry const *entry =
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(Directory_entry *)source.packet_content(packet);
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/*
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* The default value has no meaning because the switch below
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* assigns a value in each possible branch. But it is needed to
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* keep the compiler happy.
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*/
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Dirent_type type = DIRENT_TYPE_END;
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switch (entry->type) {
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case Directory_entry::TYPE_DIRECTORY: type = DIRENT_TYPE_DIRECTORY; break;
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case Directory_entry::TYPE_FILE: type = DIRENT_TYPE_FILE; break;
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case Directory_entry::TYPE_SYMLINK: type = DIRENT_TYPE_SYMLINK; break;
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}
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out.type = type;
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out.fileno = index + 1;
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strncpy(out.name, entry->name, sizeof(out.name));
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source.release_packet(packet);
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return DIRENT_OK;
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}
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Unlink_result unlink(char const *path) override
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{
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Absolute_path dir_path(path);
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dir_path.strip_last_element();
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Absolute_path file_name(path);
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file_name.keep_only_last_element();
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try {
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::File_system::Dir_handle dir = _fs.dir(dir_path.base(), false);
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Fs_handle_guard dir_guard(_fs, dir);
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_fs.unlink(dir, file_name.base() + 1);
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}
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catch (...) {
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return UNLINK_ERR_NO_ENTRY;
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}
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return UNLINK_OK;
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}
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Readlink_result readlink(char const *path, char *buf, file_size buf_size,
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file_size &out_len) override
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{
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/*
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* Canonicalize path (i.e., path must start with '/')
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*/
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Absolute_path abs_path(path);
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abs_path.strip_last_element();
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Absolute_path symlink_name(path);
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symlink_name.keep_only_last_element();
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try {
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::File_system::Dir_handle dir_handle = _fs.dir(abs_path.base(), false);
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Fs_handle_guard from_dir_guard(_fs, dir_handle);
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::File_system::Symlink_handle symlink_handle =
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_fs.symlink(dir_handle, symlink_name.base() + 1, false);
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Fs_handle_guard symlink_guard(_fs, symlink_handle);
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out_len = _read(symlink_handle, buf, buf_size, 0);
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return READLINK_OK;
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} catch (...) { }
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return READLINK_ERR_NO_ENTRY;
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}
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Rename_result rename(char const *from_path, char const *to_path) override
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{
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Absolute_path from_dir_path(from_path);
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from_dir_path.strip_last_element();
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Absolute_path from_file_name(from_path);
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from_file_name.keep_only_last_element();
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Absolute_path to_dir_path(to_path);
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to_dir_path.strip_last_element();
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Absolute_path to_file_name(to_path);
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to_file_name.keep_only_last_element();
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try {
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::File_system::Dir_handle from_dir = _fs.dir(from_dir_path.base(), false);
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Fs_handle_guard from_dir_guard(_fs, from_dir);
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::File_system::Dir_handle to_dir = _fs.dir(to_dir_path.base(), false);
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Fs_handle_guard to_dir_guard(_fs, to_dir);
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_fs.move(from_dir, from_file_name.base() + 1,
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to_dir, to_file_name.base() + 1);
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} catch (...) {
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return RENAME_ERR_NO_ENTRY; }
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return RENAME_OK;
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}
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Mkdir_result mkdir(char const *path, unsigned mode) override
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{
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/*
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* Canonicalize path (i.e., path must start with '/')
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*/
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Absolute_path abs_path(path);
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try {
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_fs.dir(abs_path.base(), true);
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return MKDIR_OK;
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}
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catch (::File_system::Permission_denied) { return MKDIR_ERR_NO_PERM; }
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catch (::File_system::Node_already_exists) { return MKDIR_ERR_EXISTS; }
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catch (::File_system::Lookup_failed) { return MKDIR_ERR_NO_ENTRY; }
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catch (::File_system::Name_too_long) { return MKDIR_ERR_NAME_TOO_LONG; }
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catch (::File_system::No_space) { return MKDIR_ERR_NO_SPACE; }
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return MKDIR_ERR_NO_PERM;
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}
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Symlink_result symlink(char const *from, char const *to) override
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{
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/*
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* We write to the symlink via the packet stream. Hence we need
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* to serialize with other packet-stream operations.
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*/
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Lock::Guard guard(_lock);
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/*
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* Canonicalize path (i.e., path must start with '/')
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*/
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Absolute_path abs_path(to);
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abs_path.strip_last_element();
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Absolute_path symlink_name(to);
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symlink_name.keep_only_last_element();
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try {
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::File_system::Dir_handle dir_handle = _fs.dir(abs_path.base(), false);
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Fs_handle_guard from_dir_guard(_fs, dir_handle);
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::File_system::Symlink_handle symlink_handle =
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_fs.symlink(dir_handle, symlink_name.base() + 1, true);
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Fs_handle_guard symlink_guard(_fs, symlink_handle);
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_write(symlink_handle, from, strlen(from) + 1, 0);
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return SYMLINK_OK;
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}
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catch (::File_system::Invalid_handle) { return SYMLINK_ERR_NO_ENTRY; }
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catch (::File_system::Node_already_exists) { return SYMLINK_ERR_EXISTS; }
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catch (::File_system::Invalid_name) { return SYMLINK_ERR_NAME_TOO_LONG; }
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catch (::File_system::Lookup_failed) { return SYMLINK_ERR_NO_ENTRY; }
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catch (::File_system::Permission_denied) { return SYMLINK_ERR_NO_PERM; }
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return SYMLINK_ERR_NO_ENTRY;
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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 (strcmp(path, "") == 0)
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path = "/";
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/*
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* XXX handle more exceptions
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*/
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::File_system::Node_handle node;
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try { node = _fs.node(path); } catch (::File_system::Lookup_failed) { return 0; }
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Fs_handle_guard node_guard(_fs, node);
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::File_system::Status status = _fs.status(node);
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return status.size / sizeof(::File_system::Directory_entry);
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}
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bool is_directory(char const *path) override
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{
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try {
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::File_system::Node_handle node = _fs.node(path);
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Fs_handle_guard node_guard(_fs, node);
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::File_system::Status status = _fs.status(node);
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return status.is_directory();
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}
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catch (...) { 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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/* check if node at path exists within file system */
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try {
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::File_system::Node_handle node = _fs.node(path);
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_fs.close(node);
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}
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catch (...) {
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return 0; }
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return path;
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}
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Open_result open(char const *path, unsigned vfs_mode, Vfs_handle **out_handle) override
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{
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Lock::Guard guard(_lock);
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Absolute_path dir_path(path);
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dir_path.strip_last_element();
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Absolute_path file_name(path);
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file_name.keep_only_last_element();
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::File_system::Mode mode;
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switch (vfs_mode & OPEN_MODE_ACCMODE) {
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default: mode = ::File_system::STAT_ONLY; break;
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case OPEN_MODE_RDONLY: mode = ::File_system::READ_ONLY; break;
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case OPEN_MODE_WRONLY: mode = ::File_system::WRITE_ONLY; break;
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case OPEN_MODE_RDWR: mode = ::File_system::READ_WRITE; break;
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}
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bool const create = vfs_mode & OPEN_MODE_CREATE;
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if (create)
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if (verbose)
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PDBG("creation of file %s requested", file_name.base() + 1);
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try {
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::File_system::Dir_handle dir = _fs.dir(dir_path.base(), false);
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Fs_handle_guard dir_guard(_fs, dir);
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::File_system::File_handle file = _fs.file(dir, file_name.base() + 1,
|
|
mode, create);
|
|
|
|
*out_handle = new (env()->heap()) Fs_vfs_handle(*this, vfs_mode, file);
|
|
return OPEN_OK;
|
|
}
|
|
catch (::File_system::Permission_denied) { return OPEN_ERR_NO_PERM; }
|
|
catch (::File_system::Invalid_handle) { return OPEN_ERR_NO_PERM; }
|
|
catch (::File_system::Lookup_failed) { return OPEN_ERR_UNACCESSIBLE; }
|
|
catch (::File_system::Node_already_exists) { return OPEN_ERR_EXISTS; }
|
|
|
|
return OPEN_ERR_UNACCESSIBLE;
|
|
}
|
|
|
|
|
|
/***************************
|
|
** File_system interface **
|
|
***************************/
|
|
|
|
static char const *name() { return "fs"; }
|
|
|
|
void sync() override
|
|
{
|
|
_fs.sync();
|
|
}
|
|
|
|
|
|
/********************************
|
|
** File I/O service interface **
|
|
********************************/
|
|
|
|
Write_result write(Vfs_handle *vfs_handle, char const *buf,
|
|
file_size buf_size, file_size &out_count) override
|
|
{
|
|
Lock::Guard guard(_lock);
|
|
|
|
Fs_vfs_handle const *handle = static_cast<Fs_vfs_handle *>(vfs_handle);
|
|
|
|
out_count = _write(handle->file_handle(), buf, buf_size, handle->seek());
|
|
|
|
return WRITE_OK;
|
|
}
|
|
|
|
Read_result read(Vfs_handle *vfs_handle, char *dst, file_size count,
|
|
file_size &out_count) override
|
|
{
|
|
Lock::Guard guard(_lock);
|
|
|
|
Fs_vfs_handle const *handle = static_cast<Fs_vfs_handle *>(vfs_handle);
|
|
|
|
::File_system::Status status = _fs.status(handle->file_handle());
|
|
file_size const size_of_file = status.size;
|
|
|
|
file_size const file_bytes_left = size_of_file >= handle->seek()
|
|
? size_of_file - handle->seek() : 0;
|
|
|
|
count = min(count, file_bytes_left);
|
|
|
|
out_count = _read(handle->file_handle(), dst, count, handle->seek());
|
|
|
|
return READ_OK;
|
|
}
|
|
|
|
Ftruncate_result ftruncate(Vfs_handle *vfs_handle, file_size len) override
|
|
{
|
|
Fs_vfs_handle const *handle = static_cast<Fs_vfs_handle *>(vfs_handle);
|
|
|
|
try {
|
|
_fs.truncate(handle->file_handle(), len);
|
|
}
|
|
catch (::File_system::Invalid_handle) { return FTRUNCATE_ERR_NO_PERM; }
|
|
catch (::File_system::Permission_denied) { return FTRUNCATE_ERR_NO_PERM; }
|
|
|
|
return FTRUNCATE_OK;
|
|
}
|
|
};
|
|
|
|
#endif /* _INCLUDE__VFS__FS_FILE_SYSTEM_H_ */
|