libc: add support for Rtc_file_system

Fixes #1241.

repos/libports/lib/mk/libc.mk

@@ -14,7 +14,7 @@ SRC_CC = atexit.cc dummies.cc rlimit.cc sysctl.cc \
          gettimeofday.cc malloc.cc progname.cc fd_alloc.cc file_operations.cc \
          plugin.cc plugin_registry.cc select.cc exit.cc environ.cc nanosleep.cc \
          libc_mem_alloc.cc pread_pwrite.cc readv_writev.cc poll.cc \
-         libc_pdbg.cc vfs_plugin.cc
+         libc_pdbg.cc vfs_plugin.cc rtc.cc
 
 INC_DIR += $(REP_DIR)/src/lib/libc
 

repos/libports/src/lib/libc/rtc.cc

@@ -0,0 +1,55 @@
+/*
+ * \brief  C-library back end
+ * \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.
+ */
+
+#include <base/printf.h>
+#include <util/string.h>
+
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+
+namespace Libc {
+	extern char const *config_rtc();
+	time_t read_rtc();
+}
+
+time_t Libc::read_rtc()
+{
+	time_t rtc = 0;
+
+	int fd = open(Libc::config_rtc(), O_RDONLY);
+	if (fd == -1)
+		return rtc;
+
+	char buf[32];
+	ssize_t n = read(fd, buf, sizeof(buf));
+	if (n > 0) {
+		buf[n - 1] = '\0';
+		struct tm tm;
+		Genode::memset(&tm, 0, sizeof(tm));
+
+		if (strptime(buf, "%Y-%m-%d %R", &tm)) {
+			rtc = mktime(&tm);
+			if (rtc == (time_t)-1)
+				rtc = 0;
+		}
+	}
+
+	close(fd);
+
+	return rtc;
+}

repos/libports/src/lib/libc/vfs_plugin.cc

@@ -27,6 +27,7 @@
 #include <vfs/log_file_system.h>
 #include <vfs/rom_file_system.h>
 #include <vfs/inline_file_system.h>
+#include <vfs/rtc_file_system.h>
 
 /* libc includes */
 #include <errno.h>
@@ -158,6 +159,7 @@ class Libc_file_system_factory : public Vfs::File_system_factory
 			_add_builtin_fs<Vfs::Log_file_system>();
 			_add_builtin_fs<Vfs::Rom_file_system>();
 			_add_builtin_fs<Vfs::Inline_file_system>();
+			_add_builtin_fs<Vfs::Rtc_file_system>();
 		}
 };
 
@@ -228,6 +230,13 @@ namespace Libc {
 		static Config_attr stderr("stderr", "");
 		return stderr.string();
 	}
+
+	char const *config_rtc() __attribute__((weak));
+	char const *config_rtc()
+	{
+		static Config_attr rtc("rtc", "");
+		return rtc.string();
+	}
 }