noux: add time modification

... and set initial time by using RTC session.

Up to now Noux used a monotic clock whose initial start value always
was '0' (which correlates to the start of the UNIX epoch) to provide
a notion of time. In addition it is now possible to use the RTC
session to set the initial value for use cases where having a proper
real-world time matters.

To use the RTC session the 'rtc' attribute of the '<config>' node
must be set to 'yes'. Thereby the session becomes a mandatory
dependency as Noux will not start without it.

Issue #1784

repos/ports/include/noux_session/sysio.h

@@ -96,6 +96,7 @@ struct Noux::Sysio
 		unsigned       gid;
 		unsigned long  inode;
 		unsigned long  device;
+		long long      mtime;
 
 		Stat & operator= (Vfs::Directory_service::Stat const &stat)
 		{
@@ -105,6 +106,7 @@ struct Noux::Sysio
 			gid    = stat.gid;
 			inode  = stat.inode;
 			device = stat.device;
+			mtime  = stat.modification_time.value;
 
 			return *this;
 		}

repos/ports/recipes/src/noux/used_apis

@@ -7,3 +7,4 @@ noux_session
 terminal_session
 timer_session
 posix
+rtc_session

repos/ports/src/lib/libc_noux/plugin.cc

@@ -397,6 +397,9 @@ static void _sysio_to_stat_struct(Noux::Sysio const *sysio, struct stat *buf)
 	buf->st_blocks  = (buf->st_size + FS_BLOCK_SIZE - 1) / FS_BLOCK_SIZE;
 	buf->st_ino     = sysio->stat_out.st.inode;
 	buf->st_dev     = sysio->stat_out.st.device;
+
+	if (sysio->stat_out.st.mtime >= 0)
+		buf->st_mtime = sysio->stat_out.st.mtime;
 }
 
 
@@ -934,6 +937,13 @@ extern "C" int gettimeofday(struct timeval *tv, struct timezone *tz)
 
 extern "C" int utimes(const char* path, const struct timeval *times)
 {
+	char * const dst     = sysio()->utimes_in.path;
+	size_t const max_len = sizeof(sysio()->utimes_in.path);
+	Genode::strncpy(dst, path, max_len);
+
+	sysio()->utimes_in.sec  = times ? times->tv_sec  : 0;
+	sysio()->utimes_in.usec = times ? times->tv_usec : 0;
+
 	if (!noux_syscall(Noux::Session::SYSCALL_UTIMES)) {
 		errno = EINVAL;
 		return -1;

repos/ports/src/noux/child.h

@@ -37,6 +37,7 @@
 #include <verbose.h>
 #include <user_info.h>
 #include <armed_timeout.h>
+#include <time_info.h>
 
 namespace Noux {
 
@@ -124,6 +125,8 @@ class Noux::Child : public Rpc_object<Session>,
 
 		User_info const &_user_info;
 
+		Time_info const &_time_info;
+
 		Parent_exit       *_parent_exit;
 		Kill_broadcaster  &_kill_broadcaster;
 		Timer::Connection &_timer_connection;
@@ -319,6 +322,7 @@ class Noux::Child : public Rpc_object<Session>,
 		Child(Child_policy::Name const &name,
 		      Verbose            const &verbose,
 		      User_info          const &user_info,
+		      Time_info          const &time_info,
 		      Parent_exit              *parent_exit,
 		      Kill_broadcaster         &kill_broadcaster,
 		      Timer::Connection        &timer_connection,
@@ -342,6 +346,7 @@ class Noux::Child : public Rpc_object<Session>,
 			_name(name),
 			_verbose(verbose),
 			_user_info(user_info),
+			_time_info(time_info),
 			_parent_exit(parent_exit),
 			_kill_broadcaster(kill_broadcaster),
 			_timer_connection(timer_connection),
@@ -521,6 +526,7 @@ class Noux::Child : public Rpc_object<Session>,
 			Child *child = new (_heap) Child(filename,
 			                                 _verbose,
 			                                 _user_info,
+			                                 _time_info,
 			                                 _parent_exit,
 			                                 _kill_broadcaster,
 			                                 _timer_connection,

repos/ports/src/noux/main.cc

@@ -27,6 +27,7 @@
 #include <kill_broadcaster.h>
 #include <vfs/dir_file_system.h>
 #include <vfs/simple_env.h>
+#include <time_info.h>
 
 namespace Noux {
 
@@ -98,7 +99,9 @@ connect_stdio(Genode::Env                                 &env,
               Vfs::File_system                            &root,
               Noux::Vfs_io_waiter_registry                &vfs_io_waiter_registry,
               Noux::Terminal_io_channel::Type              type,
-              Genode::Allocator                           &alloc)
+              Genode::Allocator                           &alloc,
+              Noux::Time_info                             &time_info,
+              Timer::Connection                           &timer)
 {
 	using namespace Vfs;
 	using namespace Noux;
@@ -142,7 +145,8 @@ connect_stdio(Genode::Env                                 &env,
 
 	return *new (alloc)
 		Vfs_io_channel(path.string(), root.leaf_path(path.string()),
-		               vfs_handle, vfs_io_waiter_registry, env.ep());
+		               vfs_handle, vfs_io_waiter_registry, env.ep(),
+		               time_info, timer);
 }
 
 
@@ -241,6 +245,8 @@ struct Noux::Main
 
 	User_info _user_info { _config.xml() };
 
+	Time_info _time_info { _env, _config.xml() };
+
 	Signal_handler<Main> _destruct_handler {
 		_env.ep(), *this, &Main::_handle_destruct };
 
@@ -273,6 +279,7 @@ struct Noux::Main
 	Noux::Child _init_child { _name_of_init_process(),
 	                          _verbose,
 	                          _user_info,
+	                          _time_info,
 	                          0,
 	                          _kill_broadcaster,
 	                          _timer_connection,
@@ -302,13 +309,13 @@ struct Noux::Main
 	Shared_pointer<Io_channel>
 		_channel_0 { &connect_stdio(_env, _terminal, _config.xml(), _root_dir,
 		             _io_response_handler.io_waiter_registry,
-		             Tio::STDIN,  _heap), _heap },
+		             Tio::STDIN,  _heap, _time_info, _timer_connection), _heap },
 		_channel_1 { &connect_stdio(_env, _terminal, _config.xml(), _root_dir,
 		            _io_response_handler.io_waiter_registry,
-		             Tio::STDOUT, _heap), _heap },
+		             Tio::STDOUT, _heap, _time_info, _timer_connection), _heap },
 		_channel_2 { &connect_stdio(_env, _terminal, _config.xml(), _root_dir,
 		             _io_response_handler.io_waiter_registry,
-		             Tio::STDERR, _heap), _heap };
+		             Tio::STDERR, _heap, _time_info, _timer_connection), _heap };
 
 	Main(Env &env) : _env(env)
 	{

repos/ports/src/noux/syscall.cc

@@ -238,7 +238,9 @@ bool Noux::Child::syscall(Noux::Session::Syscall sc)
 					                                   leaf_path,
 					                                   vfs_handle,
 					                                   _vfs_io_waiter_registry,
-					                                   _env.ep()),
+					                                   _env.ep(),
+					                                   _time_info,
+					                                   _timer_connection),
 					                                   _heap);
 
 				_sysio.open_out.fd = add_io_channel(channel);
@@ -511,6 +513,7 @@ bool Noux::Child::syscall(Noux::Session::Syscall sc)
 					child = new (_heap) Child(_child_policy.name(),
 					                          _verbose,
 					                          _user_info,
+					                          _time_info,
 					                          this,
 					                          _kill_broadcaster,
 					                          _timer_connection,
@@ -844,7 +847,8 @@ bool Noux::Child::syscall(Noux::Session::Syscall sc)
 				Milliseconds const ms =
 					_timer_connection.curr_time().trunc_to_plain_ms();
 
-				_sysio.gettimeofday_out.sec  = (ms.value / 1000);
+				_sysio.gettimeofday_out.sec  = _time_info.initial_time();
+				_sysio.gettimeofday_out.sec += (ms.value / 1000);
 				_sysio.gettimeofday_out.usec = (ms.value % 1000) * 1000;
 
 				result = true;
@@ -864,7 +868,8 @@ bool Noux::Child::syscall(Noux::Session::Syscall sc)
 				/* CLOCK_SECOND is used by time(3) in the libc. */
 				case Sysio::CLOCK_ID_SECOND:
 					{
-						_sysio.clock_gettime_out.sec    = (ms.value / 1000);
+						_sysio.clock_gettime_out.sec    = _time_info.initial_time();
+						_sysio.clock_gettime_out.sec   += (ms.value / 1000);
 						_sysio.clock_gettime_out.nsec   = 0;
 
 						result = true;
@@ -889,13 +894,42 @@ bool Noux::Child::syscall(Noux::Session::Syscall sc)
 		case SYSCALL_UTIMES:
 			{
 				/**
-				 * This systemcall is currently not implemented because we lack
+				 * Always return true, even if 'update_modification_timestamp'
-				 * the needed mechanisms in most file-systems.
+				 * failed to keep programs, e.g. make, happy.
-				 *
-				 * But we return true anyway to keep certain programs, e.g. make
-				 * happy.
 				 */
 				result = true;
+
+				char const *path   = (char const *)_sysio.utimes_in.path;
+				unsigned long sec  = _sysio.utimes_in.sec;
+				unsigned long usec = _sysio.utimes_in.usec;
+				(void)usec;
+
+				Vfs::Vfs_handle *vfs_handle = 0;
+				_root_dir.open(path, 0, &vfs_handle, _heap);
+				if (!vfs_handle) { break; }
+
+				if (!sec) {
+					Milliseconds const ms =
+						_timer_connection.curr_time().trunc_to_plain_ms();
+					sec   = _time_info.initial_time();
+					sec  += (ms.value / 1000);
+					usec  = (ms.value % 1000) * 1000;
+				}
+
+				Registered_no_delete<Vfs_io_waiter>
+					vfs_io_waiter(_vfs_io_waiter_registry);
+
+				Vfs::Timestamp ts { .value = (long long)sec };
+
+				for (;;) {
+					if (vfs_handle->fs().update_modification_timestamp(vfs_handle, ts)) {
+						break;
+					} else {
+						vfs_io_waiter.wait_for_io();
+					}
+				}
+
+				_root_dir.close(vfs_handle);
 				break;
 			}
 

repos/ports/src/noux/time_info.h

@@ -0,0 +1,104 @@
+/*
+ * \brief  Time information
+ * \author Josef Soentgen
+ * \date   2019-04-09
+ */
+
+/*
+ * Copyright (C) 2019 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU Affero General Public License version 3.
+ */
+
+#ifndef _NOUX__TIME_INFO_H_
+#define _NOUX__TIME_INFO_H_
+
+/* Genode includes */
+#include <util/string.h>
+#include <util/xml_node.h>
+#include <rtc_session/connection.h>
+
+/* Noux includes */
+#include <noux_session/sysio.h>
+
+namespace Noux {
+	class Time_info;
+	using namespace Genode;
+}
+
+
+class Noux::Time_info : Noncopyable
+{
+	private:
+
+		Constructible<Rtc::Connection> _rtc { };
+
+		Genode::int64_t _initial_time { 0 };
+
+		static bool _leap(unsigned year)
+		{
+			return ((year % 4) == 0
+				&& ((year % 100) != 0 || (year % 400) == 0));
+		}
+
+		/**
+		 * Convert RTC timestamp to UNIX epoch (UTC)
+		 */
+		static Genode::int64_t _convert(Rtc::Timestamp const &ts)
+		{
+			if (ts.year < 1970) { return 0; }
+
+			/*
+			 * Seconds per year lookup table
+			 */
+			static constexpr unsigned _secs_per_year[2] = {
+				365 * 86400, 366 * 86400,
+			};
+
+			/*
+			 * Seconds per month lookup table
+			 */
+			static constexpr unsigned _sec_per_month[13] = {
+				  0 * 86400,
+				 31 * 86400, 28 * 86400, 31 * 86400, 30 * 86400,
+				 31 * 86400, 30 * 86400, 31 * 86400, 31 * 86400,
+				 30 * 86400, 31 * 86400, 30 * 86400, 31 * 86400
+			};
+
+			Genode::int64_t time = 0;
+
+			for (unsigned i = 1970; i < ts.year; i++) {
+				/* abuse bool conversion for seconds look up */
+				time += _secs_per_year[(int)_leap(i)];
+			}
+
+			for (unsigned i = 1; i < ts.month; i++) {
+				time += _sec_per_month[i];
+			}
+			time += _leap(ts.year) * 86400LL;
+
+			time += 86400LL * (ts.day-1);
+			time +=  3600LL * ts.hour;
+			time +=    60LL * ts.minute;
+			time +=           ts.second;
+
+			return time;
+		}
+
+	public:
+
+		Time_info(Env &env, Xml_node config)
+		{
+			/* only try to establish the connection on demand */
+			bool const rtc = config.attribute_value("rtc", false);
+			if (!rtc) { return; }
+
+			_rtc.construct(env);
+			_initial_time = _convert(_rtc->current_time());
+		}
+
+		Genode::int64_t initial_time() const { return _initial_time; }
+};
+
+#endif /* _NOUX__TIME_INFO_H_ */

repos/ports/src/noux/vfs_io_channel.h

@@ -14,9 +14,13 @@
 #ifndef _NOUX__VFS_IO_CHANNEL_H_
 #define _NOUX__VFS_IO_CHANNEL_H_
 
+/* Genode includes */
+#include <timer_session/connection.h>
+
 /* Noux includes */
 #include <io_channel.h>
 #include <vfs/dir_file_system.h>
+#include <time_info.h>
 
 namespace Noux {
 	class Vfs_io_waiter;
@@ -69,11 +73,30 @@ struct Noux::Vfs_io_channel : Io_channel
 
 	bool const _dir = _fh.ds().directory(_leaf_path.base());
 
+	Time_info   const &_time_info;
+	Timer::Connection &_timer;
+
 	void _sync()
 	{
+		Milliseconds const ms =
+			_timer.curr_time().trunc_to_plain_ms();
+		uint64_t sec   = _time_info.initial_time();
+		         sec  += (ms.value / 1000);
+
+		Vfs::Timestamp ts { .value = (long long)sec };
+
 		Registered_no_delete<Vfs_io_waiter>
 			vfs_io_waiter(_vfs_io_waiter_registry);
 
+		for (;;) {
+			if (_fh.fs().update_modification_timestamp(&_fh, ts)) {
+				break;
+			} else {
+				Genode::error("_sync: update_modification_timestamp failed");
+				vfs_io_waiter.wait_for_io();
+			}
+		}
+
 		while (!_fh.fs().queue_sync(&_fh))
 			vfs_io_waiter.wait_for_io();
 
@@ -89,11 +112,13 @@ struct Noux::Vfs_io_channel : Io_channel
 	Vfs_io_channel(char const *path, char const *leaf_path,
 	               Vfs::Vfs_handle *vfs_handle,
 	               Vfs_io_waiter_registry &vfs_io_waiter_registry,
-	               Entrypoint &ep)
+	               Entrypoint &ep,
+	               Time_info const &time_info,
+	               Timer::Connection &timer)
 	:
 		_read_avail_handler(ep, *this, &Vfs_io_channel::_handle_read_avail),
 		_fh(*vfs_handle), _vfs_io_waiter_registry(vfs_io_waiter_registry),
-		_path(path), _leaf_path(leaf_path)
+		_path(path), _leaf_path(leaf_path), _time_info(time_info), _timer(timer)
 	{
 		_fh.fs().register_read_ready_sigh(&_fh, _read_avail_handler);
 	}