Commit 4c7404b9 authored by Elizabeth Figura's avatar Elizabeth Figura Committed by Greg Kroah-Hartman
Browse files

ntsync: Introduce NTSYNC_IOC_CREATE_EVENT. 



This correspond to the NT syscall NtCreateEvent().

An NT event holds a single bit of state denoting whether it is signaled or
unsignaled.

There are two types of events: manual-reset and automatic-reset. When an
automatic-reset event is acquired via a wait function, its state is reset to
unsignaled. Manual-reset events are not affected by wait functions.

Whether the event is manual-reset, and its initial state, are specified at
creation time.

Signed-off-by: default avatarElizabeth Figura <zfigura@codeweavers.com>
Link: https://lore.kernel.org/r/20241213193511.457338-9-zfigura@codeweavers.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ecc2ee36

drivers/misc/ntsync.c

+59 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ 
enum ntsync_type {

	NTSYNC_TYPE_SEM,

	NTSYNC_TYPE_MUTEX,

	NTSYNC_TYPE_EVENT,

};



/*
@@ -61,6 +62,10 @@ struct ntsync_obj { 
			pid_t owner;

			bool ownerdead;

		} mutex;

		struct {

			bool manual;

			bool signaled;

		} event;

	} u;



	/*
@@ -233,6 +238,8 @@ static bool is_signaled(struct ntsync_obj *obj, __u32 owner) 
		if (obj->u.mutex.owner && obj->u.mutex.owner != owner)

			return false;

		return obj->u.mutex.count < UINT_MAX;

	case NTSYNC_TYPE_EVENT:

		return obj->u.event.signaled;

	}



	WARN(1, "bad object type %#x\n", obj->type);
@@ -283,6 +290,10 @@ static void try_wake_all(struct ntsync_device *dev, struct ntsync_q *q, 
				obj->u.mutex.count++;

				obj->u.mutex.owner = q->owner;

				break;

			case NTSYNC_TYPE_EVENT:

				if (!obj->u.event.manual)

					obj->u.event.signaled = false;

				break;

			}

		}

		wake_up_process(q->task);
@@ -353,6 +364,28 @@ static void try_wake_any_mutex(struct ntsync_obj *mutex) 
	}

}



static void try_wake_any_event(struct ntsync_obj *event)

{

	struct ntsync_q_entry *entry;



	ntsync_assert_held(event);

	lockdep_assert(event->type == NTSYNC_TYPE_EVENT);



	list_for_each_entry(entry, &event->any_waiters, node) {

		struct ntsync_q *q = entry->q;

		int signaled = -1;



		if (!event->u.event.signaled)

			break;



		if (atomic_try_cmpxchg(&q->signaled, &signaled, entry->index)) {

			if (!event->u.event.manual)

				event->u.event.signaled = false;

			wake_up_process(q->task);

		}

	}

}



/*

 * Actually change the semaphore state, returning -EOVERFLOW if it is made

 * invalid.
@@ -622,6 +655,27 @@ static int ntsync_create_mutex(struct ntsync_device *dev, void __user *argp) 
	return fd;

}



static int ntsync_create_event(struct ntsync_device *dev, void __user *argp)

{

	struct ntsync_event_args args;

	struct ntsync_obj *event;

	int fd;



	if (copy_from_user(&args, argp, sizeof(args)))

		return -EFAULT;



	event = ntsync_alloc_obj(dev, NTSYNC_TYPE_EVENT);

	if (!event)

		return -ENOMEM;

	event->u.event.manual = args.manual;

	event->u.event.signaled = args.signaled;

	fd = ntsync_obj_get_fd(event);

	if (fd < 0)

		kfree(event);



	return fd;

}



static struct ntsync_obj *get_obj(struct ntsync_device *dev, int fd)

{

	struct file *file = fget(fd);
@@ -752,6 +806,9 @@ static void try_wake_any_obj(struct ntsync_obj *obj) 
	case NTSYNC_TYPE_MUTEX:

		try_wake_any_mutex(obj);

		break;

	case NTSYNC_TYPE_EVENT:

		try_wake_any_event(obj);

		break;

	}

}
@@ -941,6 +998,8 @@ static long ntsync_char_ioctl(struct file *file, unsigned int cmd, 
	void __user *argp = (void __user *)parm;



	switch (cmd) {

	case NTSYNC_IOC_CREATE_EVENT:

		return ntsync_create_event(dev, argp);

	case NTSYNC_IOC_CREATE_MUTEX:

		return ntsync_create_mutex(dev, argp);

	case NTSYNC_IOC_CREATE_SEM:

include/uapi/linux/ntsync.h

+6 −0
Original line number Diff line number Diff line
@@ -20,6 +20,11 @@ struct ntsync_mutex_args { 
	__u32 count;

};



struct ntsync_event_args {

	__u32 manual;

	__u32 signaled;

};



#define NTSYNC_WAIT_REALTIME	0x1



struct ntsync_wait_args {
@@ -38,6 +43,7 @@ struct ntsync_wait_args { 
#define NTSYNC_IOC_WAIT_ANY		_IOWR('N', 0x82, struct ntsync_wait_args)

#define NTSYNC_IOC_WAIT_ALL		_IOWR('N', 0x83, struct ntsync_wait_args)

#define NTSYNC_IOC_CREATE_MUTEX		_IOW ('N', 0x84, struct ntsync_mutex_args)

#define NTSYNC_IOC_CREATE_EVENT		_IOW ('N', 0x87, struct ntsync_event_args)



#define NTSYNC_IOC_SEM_RELEASE		_IOWR('N', 0x81, __u32)

#define NTSYNC_IOC_MUTEX_UNLOCK		_IOWR('N', 0x85, struct ntsync_mutex_args)