97 lines
2.4 KiB
C++
97 lines
2.4 KiB
C++
/*
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* \brief Symlink filesystem
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* \author Norman Feske
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* \date 2015-08-21
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*
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*/
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/*
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* Copyright (C) 2015-2017 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__SYMLINK_FILE_SYSTEM_H_
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#define _INCLUDE__VFS__SYMLINK_FILE_SYSTEM_H_
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#include <vfs/single_file_system.h>
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namespace Vfs { class Symlink_file_system; }
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class Vfs::Symlink_file_system : public Single_file_system
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{
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private:
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typedef Genode::String<MAX_PATH_LEN> Target;
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Target const _target;
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struct Symlink_handle final : Single_vfs_handle
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{
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Target const &_target;
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Symlink_handle(Directory_service &ds,
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File_io_service &fs,
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Genode::Allocator &alloc,
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Target const &target)
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: Single_vfs_handle(ds, fs, alloc, 0), _target(target)
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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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auto n = min(count, _target.length());
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copy_cstring(dst, _target.string(), n);
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out_count = n - 1;
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return READ_OK;
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}
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Write_result write(char const*, file_size,
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file_size&) override {
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return WRITE_ERR_INVALID; }
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bool read_ready() override { return true; }
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};
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public:
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Symlink_file_system(Vfs::Env&, Genode::Xml_node config)
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:
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Single_file_system(Node_type::SYMLINK, "symlink",
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Node_rwx::rw(), config),
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_target(config.attribute_value("target", Target()))
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{ }
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static char const *name() { return "symlink"; }
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char const *type() override { return "symlink"; }
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/*********************************
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** Directory-service interface **
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*********************************/
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Open_result open(char const *, unsigned, Vfs_handle **, Allocator&) override {
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return OPEN_ERR_UNACCESSIBLE; }
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Openlink_result openlink(char const *path, bool create,
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Vfs_handle **out_handle, Allocator &alloc) override
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{
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if (!_single_file(path))
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return OPENLINK_ERR_LOOKUP_FAILED;
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if (create)
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return OPENLINK_ERR_NODE_ALREADY_EXISTS;
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try {
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*out_handle = new (alloc) Symlink_handle(*this, *this, alloc, _target);
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return OPENLINK_OK;
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}
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catch (Genode::Out_of_ram) { return OPENLINK_ERR_OUT_OF_RAM; }
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catch (Genode::Out_of_caps) { return OPENLINK_ERR_OUT_OF_CAPS; }
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}
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};
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#endif /* _INCLUDE__VFS__SYMLINK_FILE_SYSTEM_H_ */
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