First patch by Salvatore to implement XSI semaphores with a few changes

by myself:
* renamed xsi_do_undo() to xsi_sem_undo() (there is more to XSI than sems).
* Fixed coding style issues in sys/sem.h and xsi_sem.cpp.
* Added _kern_*() syscall prototypes to syscalls.h.
* Added a TODO in xsi_sem.cpp and xsi_semaphore.h about moving union semun to
  a shared header.
* Made the team::xsi_sem_undo_requests int32 - due to padding, it would have
  needed 4 bytes anyway; please always use specific types over int/short/long.
* xsi_sem_undo() now checks if it needs to do anything - the calls in team.cpp
  no longer needs to do this.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@26676 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/posix/sys/ipc.h

@@ -6,8 +6,8 @@
 #define _SYS_IPC_H
 
 
+#include <sys/cdefs.h>
 #include <sys/types.h>
-#error functionality has not yet been implemented
 
 
 /* Mode bits for msgget(), semget(), and shmget() */
@@ -17,15 +17,15 @@
 
 /* Control commands for msgctl(), semctl(), and shmctl() */
 #define IPC_RMID	0		/* remove identifier */
-#define IPC_SET		1
-#define IPC_STAT	2
+#define IPC_SET		1		/* set options */
+#define IPC_STAT	2		/* get options */
 
 /* Private key */
-#define IPC_PRIVATE	0
+#define IPC_PRIVATE		(key_t)0
 
 
 struct ipc_perm {
-	key_t	key;
+	key_t	key;			/* IPC identifier */
 	uid_t	uid;			/* owner's user ID */
 	gid_t	gid;			/* owner's group ID */
 	uid_t	cuid;			/* creator's user ID */
@@ -34,14 +34,10 @@ struct ipc_perm {
 };
 
 
-#ifdef __cplusplus
-extern "C" {
-#endif
+__BEGIN_DECLS
 
 key_t ftok(const char *path, int id);
 
-#ifdef __cplusplus
-}
-#endif
+__END_DECLS
 
 #endif	/* _SYS_IPC_H */

headers/posix/sys/sem.h

@@ -0,0 +1,64 @@
+/*
+ * Copyright 2008, Haiku Inc. All Rights Reserved.
+ * Distributed under the terms of the MIT License.
+ */
+#ifndef _SYS_SEM_H
+#define _SYS_SEM_H
+
+#include <sys/cdefs.h>
+#include <sys/ipc.h>
+#include <sys/types.h>
+
+
+/* Semaphore operation flags */
+#define SEM_UNDO	10
+
+/* Command definition for semctl */
+#define GETPID		3	/* Get process ID of last element manipulating */
+#define GETVAL		4	/* Get semval */
+#define GETALL		5	/* Get all semval */
+#define GETNCNT		6	/* Get semncnt */
+#define GETZCNT		7	/* Get semzcnt */
+#define SETVAL		8	/* Set semval */
+#define SETALL		9	/* Set all semval */
+
+struct semid_ds {
+	struct ipc_perm		sem_perm;	/* Operation permission structure */
+	unsigned short		sem_nsems;	/* Number of semaphores in set */
+	time_t				sem_otime;	/* Last semop */
+	time_t				sem_ctime;	/* Last time changed by semctl */
+};
+
+/* Structure passed as parameter to the semop function */
+struct sembuf {
+	unsigned short	sem_num;	/* Semaphore number */
+	short			sem_op;		/* Semaphore operation */
+	short			sem_flg;	/* Operation flags */
+};
+
+/*
+ * Semaphore info structure. Useful for the ipcs
+ * standard utily
+ */
+struct seminfo {
+	int	semmni;	/* Number of semaphore identifies */
+	int semmns;	/* Number of semaphore in system */
+	int semmnu;	/* Number of undo structures in system */
+	int semmsl;	/* Max number of semaphores per id */
+	int semopm;	/* Max number of operations per semop call */
+	int semume;	/* Max number of undo entries per process */
+	int semusz;	/* Size in bytes of undo structure */
+	int semvmx;	/* Semaphore maximum valure */
+	int semaem;	/* adjust on exit max value */
+};
+
+
+__BEGIN_DECLS
+
+int		semctl(int semID, int semNum, int command, ...);
+int		semget(key_t key, int numSems, int semFlags);
+int		semop(int semID, struct sembuf *semOps, size_t numSemOps);
+
+__END_DECLS
+
+#endif	/* _SYS_SEM_H */