[RFC PATCH v2 15/29] ntsync: Introduce NTSYNC_IOC_EVENT_READ.

[Elizabeth Figura]

This corresponds to the NT syscall NtQueryEvent().

This returns the signaled state of the event and whether it is manual-reset.

Signed-off-by: Elizabeth Figura <zfigura@xxxxxxxxxxxxxxx>
---
 drivers/misc/ntsync.c       | 21 +++++++++++++++++++++
 include/uapi/linux/ntsync.h |  1 +
 2 files changed, 22 insertions(+)

diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c
index 7f5f96ec7c69..5439c1c9e90f 100644
--- a/drivers/misc/ntsync.c
+++ b/drivers/misc/ntsync.c
@@ -546,6 +546,25 @@ static int ntsync_mutex_read(struct ntsync_obj *mutex, void __user *argp)
 	return ret;
 }
 
+static int ntsync_event_read(struct ntsync_obj *event, void __user *argp)
+{
+	struct ntsync_event_args __user *user_args = argp;
+	struct ntsync_event_args args;
+
+	if (event->type != NTSYNC_TYPE_EVENT)
+		return -EINVAL;
+
+	args.event = 0;
+	spin_lock(&event->lock);
+	args.manual = event->u.event.manual;
+	args.signaled = event->u.event.signaled;
+	spin_unlock(&event->lock);
+
+	if (copy_to_user(user_args, &args, sizeof(args)))
+		return -EFAULT;
+	return 0;
+}
+
 static int ntsync_obj_release(struct inode *inode, struct file *file)
 {
 	struct ntsync_obj *obj = file->private_data;
@@ -579,6 +598,8 @@ static long ntsync_obj_ioctl(struct file *file, unsigned int cmd,
 		return ntsync_event_reset(obj, argp);
 	case NTSYNC_IOC_EVENT_PULSE:
 		return ntsync_event_set(obj, argp, true);
+	case NTSYNC_IOC_EVENT_READ:
+		return ntsync_event_read(obj, argp);
 	default:
 		return -ENOIOCTLCMD;
 	}
diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h
index a1d0ef581212..582d33b0dcac 100644
--- a/include/uapi/linux/ntsync.h
+++ b/include/uapi/linux/ntsync.h
@@ -53,5 +53,6 @@ struct ntsync_wait_args {
 #define NTSYNC_IOC_EVENT_PULSE		_IOR ('N', 0x8a, __u32)
 #define NTSYNC_IOC_SEM_READ		_IOR ('N', 0x8b, struct ntsync_sem_args)
 #define NTSYNC_IOC_MUTEX_READ		_IOR ('N', 0x8c, struct ntsync_mutex_args)
+#define NTSYNC_IOC_EVENT_READ		_IOR ('N', 0x8d, struct ntsync_event_args)
 
 #endif
-- 
2.43.0