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

100 lines
2.1 KiB
C++

/*
* \brief Rtc file system
* \author Josef Soentgen
* \date 2014-08-20
*/
/*
* Copyright (C) 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__RTC_FILE_SYSTEM_H_
#define _INCLUDE__VFS__RTC_FILE_SYSTEM_H_
/* Genode includes */
#include <rtc_session/connection.h>
#include <vfs/file_system.h>
namespace Vfs { class Rtc_file_system; }
class Vfs::Rtc_file_system : public Single_file_system
{
private:
Rtc::Connection _rtc;
public:
Rtc_file_system(Xml_node config)
:
Single_file_system(NODE_TYPE_CHAR_DEVICE, name(), config)
{ }
static char const *name() { return "rtc"; }
/*********************************
** Directory-service interface **
*********************************/
Stat_result stat(char const *path, Stat &out) override
{
Stat_result result = Single_file_system::stat(path, out);
out.mode |= 0444;
return result;
}
/********************************
** File I/O service interface **
********************************/
Write_result write(Vfs_handle *, char const *, file_size,
file_size &) override
{
return WRITE_ERR_IO;
}
/**
* Read the current time from the Rtc session
*
* On each read the current time is queried and afterwards formated
* as '%Y-%m-%d %H:%M\n'.
*/
Read_result read(Vfs_handle *vfs_handle, char *dst, file_size count,
file_size &out_count) override
{
enum { TIMESTAMP_LEN = 17 };
file_size seek = vfs_handle->seek();
if (seek >= TIMESTAMP_LEN) {
out_count = 0;
return READ_OK;
}
Rtc::Timestamp ts = _rtc.current_time();
char buf[TIMESTAMP_LEN+1];
char *b = buf;
unsigned n = Genode::snprintf(buf, sizeof(buf), "%04u-%02u-%02u %02u:%02u\n",
ts.year, ts.month, ts.day, ts.hour, ts.minute);
n -= seek;
b += seek;
file_size len = count > n ? n : count;
Genode::memcpy(dst, b, len);
out_count = len;
return READ_OK;
}
};
#endif /* _INCLUDE__VFS__RTC_FILE_SYSTEM_H_ */