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 */

headers/private/kernel/posix/xsi_semaphore.h

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2008, Haiku Inc. All rights reserved.
+ * Distributed under the terms of the MIT License.
+ */
+#ifndef KERNEL_XSI_SEMAPHORE_H
+#define KERNEL_XSI_SEMAPHORE_H
+
+#include <sys/sem.h>
+#include <sys/cdefs.h>
+
+#include <OS.h>
+
+#include <kernel.h>
+
+
+// TODO: move into a system/posix/xsi_semaphore_defs.h file to be shared with
+// xsi_sem.cpp in libroot!
+union semun {
+	int					val;
+	struct semid_ds		*buf;
+	unsigned short		*array;
+};
+
+
+__BEGIN_DECLS
+
+extern void xsi_ipc_init();
+extern void xsi_sem_undo(team_id teamID, int32 numberOfUndos);
+
+/* user calls */
+int _user_xsi_semget(key_t key, int numberOfSemaphores, int flags);
+int _user_xsi_semctl(int semaphoreID, int semaphoreNumber, int command,
+	union semun* args);
+status_t _user_xsi_semop(int semaphoreID, struct sembuf *semOps,
+	size_t numSemOps);
+
+__END_DECLS
+
+#endif	/* KERNEL_XSI_SEMAPHORE_H */

headers/private/kernel/thread_types.h

@@ -182,6 +182,7 @@ struct team {
 	int32			flags;
 	void			*io_context;
 	struct realtime_sem_context	*realtime_sem_context;
+	int32			xsi_sem_undo_requests;
 	sem_id			death_sem;		// semaphore to wait on for dying threads
 	struct list		dead_threads;
 	int				dead_threads_count;

headers/private/system/syscalls.h

@@ -30,6 +30,8 @@ struct rlimit;
 struct sigaction;
 struct stat;
 struct _sem_t;
+struct sembuf;
+union semun;
 
 struct disk_device_job_progress_info;
 struct partitionable_space_data;
@@ -55,24 +57,26 @@ extern int			_kern_getrlimit(int resource, struct rlimit * rlp);
 extern int			_kern_setrlimit(int resource, const struct rlimit * rlp);
 
 extern status_t		_kern_shutdown(bool reboot);
-extern status_t		_kern_get_safemode_option(const char *parameter, char *buffer, size_t *_bufferSize);
+extern status_t		_kern_get_safemode_option(const char *parameter,
+						char *buffer, size_t *_bufferSize);
 
 extern ssize_t		_kern_wait_for_objects(object_wait_info* infos, int numInfos,
 						uint32 flags, bigtime_t timeout);
 
-
 /* sem functions */
 extern sem_id		_kern_create_sem(int count, const char *name);
 extern status_t		_kern_delete_sem(sem_id id);
 extern status_t		_kern_switch_sem(sem_id releaseSem, sem_id id);
-extern status_t		_kern_switch_sem_etc(sem_id releaseSem, sem_id id, uint32 count,
-						uint32 flags, bigtime_t timeout);
+extern status_t		_kern_switch_sem_etc(sem_id releaseSem, sem_id id,
+						uint32 count, uint32 flags, bigtime_t timeout);
 extern status_t		_kern_acquire_sem(sem_id id);
-extern status_t		_kern_acquire_sem_etc(sem_id id, uint32 count, uint32 flags, bigtime_t timeout);
+extern status_t		_kern_acquire_sem_etc(sem_id id, uint32 count, uint32 flags,
+						bigtime_t timeout);
 extern status_t		_kern_release_sem(sem_id id);
 extern status_t		_kern_release_sem_etc(sem_id id, uint32 count, uint32 flags);
 extern status_t		_kern_get_sem_count(sem_id id, int32* thread_count);
-extern status_t		_kern_get_sem_info(sem_id semaphore, struct sem_info *info, size_t size);
+extern status_t		_kern_get_sem_info(sem_id semaphore, struct sem_info *info,
+						size_t size);
 extern status_t		_kern_get_next_sem_info(team_id team, int32 *cookie,
 						struct sem_info *info, size_t size);
 extern status_t		_kern_set_sem_owner(sem_id id, team_id proc);
@@ -89,8 +93,14 @@ extern status_t		_kern_realtime_sem_get_value(sem_id semID, int* value);
 extern status_t		_kern_realtime_sem_post(sem_id semID);
 extern status_t		_kern_realtime_sem_wait(sem_id semID, bigtime_t timeout);
 
-/* team & thread syscalls */
+/* POSIX XSI semaphore syscalls */
+extern int			_kern_xsi_semget(key_t key, int numSems, int flags);
+extern int			_kern_xsi_semctl(int semID, int semNumber, int command,
+						union semun* args);
+extern status_t		_kern_xsi_semop(int semID, struct sembuf *semOps,
+						size_t numSemOps);
 
+/* team & thread syscalls */
 extern thread_id	_kern_load_image(const char* const* flatArgs,
 						size_t flatArgsSize, int32 argCount, int32 envCount,
 						int32 priority, uint32 flags, port_id errorPort,

src/system/kernel/main.cpp

@@ -37,6 +37,7 @@
 #include <Notifications.h>
 #include <port.h>
 #include <posix/realtime_sem.h>
+#include <posix/xsi_semaphore.h>
 #include <real_time_clock.h>
 #include <sem.h>
 #include <smp.h>
@@ -174,7 +175,9 @@ _start(kernel_args *bootKernelArgs, int currentCPU)
 		TRACE("init kernel daemons\n");
 		kernel_daemon_init();
 		arch_platform_init_post_thread(&sKernelArgs);
+		TRACE("init posix semaphores\n");
 		realtime_sem_init();
+		xsi_ipc_init();
 
 		TRACE("init VM threads\n");
 		vm_init_post_thread(&sKernelArgs);

src/system/kernel/posix/Jamfile

@@ -4,6 +4,7 @@ UsePrivateHeaders shared ;
 
 KernelMergeObject kernel_posix.o : 
 	realtime_sem.cpp
+	xsi_semaphore.cpp
 
 	: $(TARGET_KERNEL_PIC_CCFLAGS)
 ;

src/system/kernel/syscalls.cpp

@@ -17,6 +17,7 @@
 #include <vm.h>
 #include <thread.h>
 #include <posix/realtime_sem.h>
+#include <posix/xsi_semaphore.h>
 #include <sem.h>
 #include <port.h>
 #include <cpu.h>

src/system/kernel/team.cpp

@@ -31,6 +31,7 @@
 #include <ksignal.h>
 #include <port.h>
 #include <posix/realtime_sem.h>
+#include <posix/xsi_semaphore.h>
 #include <sem.h>
 #include <syscall_process_info.h>
 #include <syscall_restart.h>
@@ -699,6 +700,7 @@ create_team_struct(const char *name, bool kernel)
 	team->io_context = NULL;
 	team->address_space = NULL;
 	team->realtime_sem_context = NULL;
+	team->xsi_sem_undo_requests = 0;
 	team->thread_list = NULL;
 	team->main_thread = NULL;
 	team->loading_info = NULL;
@@ -1322,6 +1324,7 @@ exec_team(const char *path, char**& _flatArgs, size_t flatArgsSize,
 
 	delete_team_user_data(team);
 	vm_delete_areas(team->address_space);
+	xsi_sem_undo(team->id, team->xsi_sem_undo_requests);
 	delete_owned_ports(team->id);
 	sem_delete_owned_sems(team->id);
 	remove_images(team);
@@ -2338,6 +2341,7 @@ team_delete_team(struct team *team)
 
 	vfs_free_io_context(team->io_context);
 	delete_realtime_sem_context(team->realtime_sem_context);
+	xsi_sem_undo(team->id, team->xsi_sem_undo_requests);
 	delete_owned_ports(teamID);
 	sem_delete_owned_sems(teamID);
 	remove_images(team);

src/system/libroot/posix/sys/Jamfile

@@ -7,6 +7,7 @@ MergeObject posix_sys.o :
 	chmod.c
 	flock.c
 	ftime.c
+	ftok.c
 	getrusage.c
  	gettimeofday.c
 	itimer.c
@@ -23,4 +24,5 @@ MergeObject posix_sys.o :
  	uname.c
  	utimes.c
 	wait.c
+	xsi_sem.cpp
 ;

src/system/libroot/posix/sys/ftok.c

@@ -0,0 +1,22 @@
+/*
+ * Copyright 2008, Haiku Inc. All rights reserved.
+ * Distributed under the terms of the MIT License.
+ *
+ * Authors:
+ *		Salvatore Benedetto <salvatore.benedetto@gmail.com>
+ */
+
+#include <sys/ipc.h>
+#include <sys/stat.h>
+
+
+key_t
+ftok(const char *path, int id)
+{
+	struct stat st;
+
+	if (stat(path, &st) < 0)
+		return (key_t)-1;
+
+	return (key_t)(id << 24 | (st.st_dev & 0xff) << 16 | (st.st_ino & 0xffff));
+}

src/system/libroot/posix/sys/xsi_sem.cpp

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2008, Haiku Inc. All rights reserved.
+ * Distributed under the terms of the MIT License.
+ *
+ * Authors:
+ *		Salvatore Benedetto <salvatore.benedetto@gmail.com>
+ */
+
+#include <sys/sem.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdarg.h>
+#include <stdlib.h>
+
+#include <OS.h>
+
+//#include <posix/xsi_semaphore_defs.h>
+#include <syscall_utils.h>
+#include <syscalls.h>
+
+// TODO: this should be removed when the above commented header exists
+#if 1
+/*
+ * For the semctl option argument, the user
+ * should declare explicitly the following union
+ */
+union semun {
+	int				val;
+	struct semid_ds	*buf;
+	unsigned short	*array;
+};
+#endif
+
+int
+semget(key_t key, int numSems, int semFlags)
+{
+	RETURN_AND_SET_ERRNO(_kern_xsi_semget(key, numSems, semFlags));
+}
+
+
+int
+semctl(int semID, int semNum, int command, ...)
+{
+	union semun arg;
+	va_list args;
+
+	switch (command) {
+		case GETVAL:
+		case GETPID:
+		case GETNCNT:
+		case GETZCNT:
+		case IPC_RMID:
+			RETURN_AND_SET_ERRNO(_kern_xsi_semctl(semID, semNum, command, 0));
+
+		case SETVAL:
+		case GETALL:
+		case SETALL:
+		case IPC_STAT:
+		case IPC_SET:
+			va_start(args, command);
+			arg = va_arg(args, union semun);
+			va_end(args);
+			RETURN_AND_SET_ERRNO(_kern_xsi_semctl(semID, semNum, command,
+				&arg));
+
+		default:
+			return EINVAL;
+	}
+}
+
+
+int
+semop(int semID, struct sembuf *semOps, size_t numSemOps)
+{
+	RETURN_AND_SET_ERRNO(_kern_xsi_semop(semID, semOps, numSemOps));
+}