diff --git a/include/ntapi/nt_ipc.h b/include/ntapi/nt_ipc.h
index d799587..80fc34c 100644
--- a/include/ntapi/nt_ipc.h
+++ b/include/ntapi/nt_ipc.h
@@ -4,6 +4,29 @@
 #include "nt_abi.h"
 #include "nt_object.h"
 
+/* friendly ipc guids */
+#define NT_IPC_GUID_SEMCTL		{0xe47c05df,0x5f5c,0x4762,{0xa2,0x79,0xd2,0x82,0xf5,0x39,0xea,0xdf}}
+#define NT_IPC_GUID_SEMKEY		{0xc6e442c3,0x2ac5,0x4d1d,{0x92,0xf3,0x6e,0x10,0xc6,0x1f,0x53,0x79}}
+#define NT_IPC_GUID_SEMPID		{0x571ac9bb,0x22eb,0x43f2,{0x8d,0xd6,0x64,0x39,0x49,0xa6,0xe9,0x1f}}
+
+/* friendly ipc object directory prefixes */
+#define NT_IPC_OBJDIR_PREFIX_SEMCTL	{'s','e','m','c','t','l'}
+#define NT_IPC_OBJDIR_PREFIX_SEMKEY	{'s','e','m','k','e','y'}
+#define NT_IPC_OBJDIR_PREFIX_SEMPID	{'s','e','m','p','i','d'}
+
+
+/* ipc commands */
+#define NT_IPC_CMD_RMID			(0)
+#define NT_IPC_CMD_SET 			(1)
+#define NT_IPC_CMD_STAT			(2)
+#define NT_IPC_CMD_INFO			(3)
+
+
+/* ipc special keys */
+#define NT_IPC_KEY_PRIVATE		(0)
+
+
+/* ipc extension interfaces */
 typedef int32_t __stdcall	ntapi_ipc_create_pipe(
 	__out		void **		hpipe_read,
 	__out		void **		hpipe_write,
diff --git a/include/ntapi/nt_port.h b/include/ntapi/nt_port.h
index 9bfa440..45755e0 100644
--- a/include/ntapi/nt_port.h
+++ b/include/ntapi/nt_port.h
@@ -35,6 +35,8 @@ typedef enum _nt_port_type {
 	NT_PORT_TYPE_DAEMON,	/* {'d','a','e','m','o','n'} */
 	NT_PORT_TYPE_SYMLNK,	/* {'s','y','m','l','n','k'} */
 	NT_PORT_TYPE_NTPROC,	/* {'n','t','p','r','o','c'} */
+	NT_PORT_TYPE_SEMCTL,	/* {'s','e','m','c','t','l'} */
+	NT_PORT_TYPE_SEMSVC,	/* {'s','e','m','s','v','c'} */
 	NT_PORT_TYPE_CAP
 } nt_port_type;
 
@@ -53,6 +55,8 @@ typedef enum _nt_port_subtype {
 #define NT_PORT_GUID_DAEMON	{0xcf765d9e,0x6bd8,0x4a8d,{0x8a,0x21,0x17,0x34,0xcd,0x3a,0x8d,0xa7}}
 #define NT_PORT_GUID_SYMLNK	{0xfe1b8480,0x833d,0x44df,{0x90,0x99,0xc1,0xf6,0x9c,0x11,0xd4,0x0b}}
 #define NT_PORT_GUID_NTPROC	{0xd7f3f3a5,0x3e82,0x4f3e,{0x9d,0x6c,0x36,0x18,0xde,0xfa,0xc6,0x69}}
+#define NT_PORT_GUID_SEMCTL	{0x7850be42,0x7eef,0x4c3d,{0xa7,0x05,0xa4,0xd8,0x47,0x3f,0x67,0x56}}
+#define NT_PORT_GUID_SEMSVC	{0xa50f4380,0x854a,0x4260,{0x9d,0x8d,0xc2,0xc2,0xa1,0x16,0xde,0xf3}}
 
 /* lpc messages */
 #define NT_LPC_REFUSE_CONNECTION	0x0000
diff --git a/include/ntapi/nt_sem.h b/include/ntapi/nt_sem.h
new file mode 100644
index 0000000..768007d
--- /dev/null
+++ b/include/ntapi/nt_sem.h
@@ -0,0 +1,66 @@
+#ifndef _NT_SEM_H_
+#define _NT_SEM_H_
+
+#include "nt_abi.h"
+#include "nt_object.h"
+
+/* semaphore commands */
+#define NT_SEM_CMD_GETPID		(11)
+#define NT_SEM_CMD_GETVAL		(12)
+#define NT_SEM_CMD_GETALL		(13)
+#define NT_SEM_CMD_GETNCNT		(14)
+#define NT_SEM_CMD_GETZCNT		(15)
+#define NT_SEM_CMD_SETVAL		(16)
+#define NT_SEM_CMD_SETALL		(17)
+
+
+/* semaphore command flags */
+#define NT_SEM_FLAG_NOWAIT		(0x0800)
+#define NT_SEM_FLAG_UNDO		(0x1000)
+
+
+/* semaphore info */
+typedef struct __attr_ptr_size_aligned__ _nt_sem_info {
+	void *		hport;
+	void *		hprocess;
+	void *		hthread;
+	void *		section;
+	void *		section_addr;
+	size_t		section_size;
+	void *		apc_routine;
+	void *		apc_context;
+	int32_t		semkey;
+	int32_t		semslots;
+	int32_t		semid;
+	int32_t		semnum;
+	int32_t		semcmd;
+	int32_t		sempid;
+	int32_t		semncnt;
+	int32_t		semzcnt;
+	int32_t		semval;
+	int32_t		semadj;
+	nt_filetime	semotime;
+	nt_filetime	semctime;
+	uint32_t	ipcuid;
+	uint32_t	ipcgid;
+	uint32_t	ipccuid;
+	uint32_t	ipccgid;
+	uint32_t	ipcmode;
+	int32_t		ipcseq;
+	uint32_t	ntaccess;
+	uint32_t	ntattr;
+	uint32_t	ntshare;
+	uint32_t	ntoptions;
+	nt_iosb *	riosb;
+	void *		hevent[2];
+} nt_sem_info;
+
+
+/* semaphore operation */
+typedef struct _nt_sem_op {
+        uint16_t	semnum;
+        int16_t		semop;
+        int16_t		semflag;
+} nt_sem_op;
+
+#endif
diff --git a/include/ntapi/nt_tty.h b/include/ntapi/nt_tty.h
index dc8c4f3..f0d7c5d 100644
--- a/include/ntapi/nt_tty.h
+++ b/include/ntapi/nt_tty.h
@@ -15,6 +15,7 @@
 #include "nt_process.h"
 #include "nt_port.h"
 #include "nt_termios.h"
+#include "nt_sem.h"
 
 /* tty affiliation */
 typedef struct _nt_tty_affiliation {
@@ -59,6 +60,7 @@ typedef enum _nt_tty_opcode {
 	NT_TTY_QUERY_INFORMATION_THREAD,
 	NT_TTY_QUERY_INFORMATION_SECTION,
 	NT_TTY_QUERY_INFORMATION_PTY,
+	NT_TTY_QUERY_INFORMATION_SEMAPHORE,
 	/* peer daemon calls */
 	NT_TTY_REQUEST_PEER,
 	NT_TTY_SIGNAL_PEER,
@@ -73,6 +75,17 @@ typedef enum _nt_tty_opcode {
 	NT_TTY_PTY_IOCTL,
 	NT_TTY_PTY_CANCEL,
 	NT_TTY_PTY_PEEK,
+	/* semaphore */
+	NT_TTY_SEM_ALLOC,
+	NT_TTY_SEM_FREE,
+	NT_TTY_SEM_OPEN,
+	NT_TTY_SEM_CLOSE,
+	NT_TTY_SEM_QUERY,
+	NT_TTY_SEM_SET,
+	NT_TTY_SEM_FCNTL,
+	NT_TTY_SEM_IOCTL,
+	NT_TTY_SEM_CANCEL,
+	NT_TTY_SEM_TRACE,
 	/* virtual mount system */
 	NT_TTY_VMS_QUERY,
 	NT_TTY_VMS_REQUEST,
@@ -100,6 +113,7 @@ typedef enum _nt_tty_server_info_class {
 	NT_TTY_SERVER_PTS_SLOT_INFORMATION,
 	NT_TTY_SERVER_DBM_SLOT_INFORMATION,
 	NT_TTY_SERVER_DBG_SLOT_INFORMATION,
+	NT_TTY_SERVER_SEM_SLOT_INFORMATION,
 	NT_TTY_SERVER_INFORMATION_CAP
 } nt_tty_server_info_class;
 
@@ -312,6 +326,15 @@ typedef struct __attr_ptr_size_aligned__ _nt_pty_sigctl_msg {
 } nt_pty_sigctl_msg;
 
 
+typedef struct __attr_ptr_size_aligned__ _nt_sem_info_msg {
+	nt_port_message			header;
+	struct {
+		nt_tty_msg_info		ttyinfo;
+		nt_sem_info		seminfo;
+	} data;
+} nt_sem_info_msg;
+
+
 typedef struct __attr_ptr_size_aligned__ _nt_tty_session_msg {
 	nt_port_message			header;
 	struct {
@@ -333,6 +356,7 @@ typedef struct __attr_ptr_size_aligned__ _nt_tty_port_msg {
 		nt_pty_io_info		ioinfo;
 		nt_pty_client_info	clientinfo;
 		nt_tty_session_info	sessioninfo;
+		nt_sem_info		seminfo;
 	};
 } nt_tty_port_msg;
 
diff --git a/project/headers.mk b/project/headers.mk
index bb502bf..c8d5a25 100644
--- a/project/headers.mk
+++ b/project/headers.mk
@@ -37,6 +37,7 @@ API_HEADERS = \
 	$(SOURCE_DIR)/include/$(PACKAGE)/./nt_registry.h \
 	$(SOURCE_DIR)/include/$(PACKAGE)/./nt_section.h \
 	$(SOURCE_DIR)/include/$(PACKAGE)/./nt_security.h \
+	$(SOURCE_DIR)/include/$(PACKAGE)/./nt_sem.h \
 	$(SOURCE_DIR)/include/$(PACKAGE)/./nt_slist.h \
 	$(SOURCE_DIR)/include/$(PACKAGE)/./nt_socket.h \
 	$(SOURCE_DIR)/include/$(PACKAGE)/./nt_stat.h \
diff --git a/src/port/ntapi_port_name_helper.c b/src/port/ntapi_port_name_helper.c
index 7e013a3..8c811fa 100644
--- a/src/port/ntapi_port_name_helper.c
+++ b/src/port/ntapi_port_name_helper.c
@@ -19,7 +19,9 @@ static const __port_service_prefix	__port_service_prefixes[NT_PORT_TYPE_CAP][NT_
 					{{'v','m','o','u','n','t'}},
 					{{'d','a','e','m','o','n'}},
 					{{'s','y','m','l','n','k'}},
-					{{'n','t','p','r','o','c'}}};
+					{{'n','t','p','r','o','c'}},
+					{{'s','e','m','c','t','l'}},
+					{{'s','e','m','s','v','c'}}};
 
 static const nt_guid		__port_guids[NT_PORT_TYPE_CAP][NT_PORT_SUBTYPE_CAP] = {
 					{NT_PORT_GUID_DEFAULT},
@@ -27,7 +29,9 @@ static const nt_guid		__port_guids[NT_PORT_TYPE_CAP][NT_PORT_SUBTYPE_CAP] = {
 					{NT_PORT_GUID_VMOUNT},
 					{NT_PORT_GUID_DAEMON},
 					{NT_PORT_GUID_SYMLNK},
-					{NT_PORT_GUID_NTPROC}};
+					{NT_PORT_GUID_NTPROC},
+					{NT_PORT_GUID_SEMCTL},
+					{NT_PORT_GUID_SEMSVC}};
 
 int32_t __stdcall __ntapi_tt_port_guid_from_type(
 	__out	nt_guid *		guid,