Index: uspace/lib/c/include/ipc/logger.h
===================================================================
--- uspace/lib/c/include/ipc/logger.h	(revision c99d4707e5fb7ab999abcb095089419583d090e2)
+++ uspace/lib/c/include/ipc/logger.h	(revision c99d4707e5fb7ab999abcb095089419583d090e2)
@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2012 Vojtech Horky
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * - Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ * - The name of the author may not be used to endorse or promote products
+ *   derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/** @addtogroup libc
+ * @{
+ */
+
+#ifndef LIBC_IPC_LOGGER_H_
+#define LIBC_IPC_LOGGER_H_
+
+#include <ipc/common.h>
+
+typedef enum {
+	/** Set (global) default displayed logging level.
+	 *
+	 * Arguments: new log level.
+	 * Returns: error code
+	 */
+	LOGGER_CONTROL_SET_DEFAULT_LEVEL = IPC_FIRST_USER_METHOD,
+	/** Set displayed level for given log.
+	 *
+	 * Arguments: new log level.
+	 * Returns: error code
+	 * Followed by: string with full log name.
+	 */
+	LOGGER_CONTROL_SET_LOG_LEVEL
+} logger_control_request_t;
+
+typedef enum {
+	/** Create new log.
+	 *
+	 * Arguments: parent log id (0 for top-level log).
+	 * Returns: error code, log id
+	 * Followed by: string with log name.
+	 */
+	LOGGER_WRITER_CREATE_LOG = IPC_FIRST_USER_METHOD,
+	/** Write a message to a given log.
+	 *
+	 * Arguments: log id, message severity level (log_level_t)
+	 * Returns: error code
+	 * Followed by: string with the message.
+	 */
+	LOGGER_WRITER_MESSAGE
+} logger_writer_request_t;
+
+typedef enum {
+	/** Interface for controlling logger behavior. */
+	LOGGER_INTERFACE_CONTROL,
+	/** Interface for servers writing to the log. */
+	LOGGER_INTERFACE_WRITER
+} logger_interface_t;
+
+#endif
+
+/** @}
+ */
Index: uspace/lib/c/include/ipc/services.h
===================================================================
--- uspace/lib/c/include/ipc/services.h	(revision 917797f1cec4a09619bf92bcb7aaec9ac4de9839)
+++ uspace/lib/c/include/ipc/services.h	(revision c99d4707e5fb7ab999abcb095089419583d090e2)
@@ -45,4 +45,5 @@
 	SERVICE_VFS        = FOURCC('v', 'f', 's', ' '),
 	SERVICE_LOC        = FOURCC('l', 'o', 'c', ' '),
+	SERVICE_LOGGER     = FOURCC('l', 'o', 'g', 'g'),
 	SERVICE_DEVMAN     = FOURCC('d', 'e', 'v', 'n'),
 	SERVICE_IRC        = FOURCC('i', 'r', 'c', ' '),