[time] Add the sleep command

Reviewed-by: Stefan Hajnoczi <stefanha@gmail.com>
Reviewed-by: Thomas Miletich <thomas.miletich@gmail.com>
Modified-by: Michael Brown <mcb30@etherboot.org>
Signed-off-by: Michael Brown <mcb30@etherboot.org>

src/config/general.h

 #define DHCP_CMD		/* DHCP management commands */
 #define SANBOOT_CMD		/* SAN boot commands */
 #define LOGIN_CMD		/* Login command */
-#undef	TIME_CMD		/* Time command */
+#undef	TIME_CMD		/* Time commands */
 
 /*
  * Obscure configuration options

src/hci/commands/time_cmd.c

  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * March-19-2009 @ 02:44: Added sleep command.
+ * Shao Miller <shao.miller@yrdsb.edu.on.ca>.
  */
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include <gpxe/command.h>
+#include <gpxe/nap.h>
 #include <gpxe/timer.h>
 
 static int time_exec ( int argc, char **argv ) {
 	.exec = time_exec,
 };
 
+static int sleep_exec ( int argc, char **argv ) {
+	unsigned long start, delay;
+
+	if ( argc == 1 ||
+	     !strcmp ( argv[1], "--help" ) ||
+	     !strcmp ( argv[1], "-h" ))
+	{
+		printf ( "Usage:\n"
+			 "  %s <seconds>\n"
+			 "\n"
+			 "Sleep for <seconds> seconds\n",
+			 argv[0] );
+		return 1;
+	}
+	start = currticks();
+	delay = strtoul ( argv[1], NULL, 0 ) * ticks_per_sec();
+	while ( ( currticks() - start ) <= delay )
+		cpu_nap();
+	return 0;
+}
+
+struct command sleep_command __command = {
+	.name = "sleep",
+	.exec = sleep_exec,
+};