24b1f269be
The intention of Packet_ref was to allow clients to place opaque references into the packet descriptor itself, which could be observed on packet completion. Currently no component in our sources uses this feature and beyond that it is questionable if it should be used at all: If the server tampers with the ref the client may easily be confused into observing an incorrect or invalid context. It seems better to remove the opaque context from the descriptor and leave the actual implementation to the client and its needs.
628 lines
16 KiB
C++
628 lines
16 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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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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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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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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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);
|
|
Fs_handle_guard dir_guard(_fs, dir);
|
|
|
|
::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_ */
|