genode/repos/os/include/vfs/zero_file_system.h

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/*
* \brief zero filesystem
* \author Josef Soentgen
* \author Norman Feske
* \date 2012-07-31
*/
/*
* Copyright (C) 2012-2014 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU General Public License version 2.
*/
#ifndef _INCLUDE__VFS__ZERO_FILE_SYSTEM_H_
#define _INCLUDE__VFS__ZERO_FILE_SYSTEM_H_
#include <vfs/file_system.h>
namespace Vfs { class Zero_file_system; }
struct Vfs::Zero_file_system : Single_file_system
{
Zero_file_system(Xml_node config)
:
Single_file_system(NODE_TYPE_CHAR_DEVICE, name(), config)
{ }
static char const *name() { return "zero"; }
/********************************
** File I/O service interface **
********************************/
Write_result write(Vfs_handle *, char const *, file_size count,
file_size &count_out) override
{
count_out = count;
return WRITE_OK;
}
Read_result read(Vfs_handle *vfs_handle, char *dst, file_size count,
file_size &out_count) override
{
memset(dst, 0, count);
out_count = count;
return READ_OK;
}
};
#endif /* _INCLUDE__VFS__ZERO_FILE_SYSTEM_H_ */