[PATCH v3 13/30] ntsync: Introduce NTSYNC_IOC_SEM_READ.

Elizabeth Figura
2024-03-29T00:24:25Z

This corresponds to the NT syscall NtQuerySemaphore().

This returns the current count and maximum count of the semaphore.

Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com>
---
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 adba4657bf26..961e8d241602 100644
--- a/drivers/misc/ntsync.c
+++ b/drivers/misc/ntsync.c
@@ -532,6 +532,25 @@ static int ntsync_event_reset(struct ntsync_obj *event, void __user *argp)
return 0;
}

+static int ntsync_sem_read(struct ntsync_obj *sem, void __user *argp)
+{
+ struct ntsync_sem_args __user *user_args = argp;
+ struct ntsync_sem_args args;
+
+ if (sem->type != NTSYNC_TYPE_SEM)
+ return -EINVAL;
+
+ args.sem = 0;
+ spin_lock(&sem->lock);
+ args.count = sem->u.sem.count;
+ args.max = sem->u.sem.max;
+ spin_unlock(&sem->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;
@@ -551,6 +570,8 @@ static long ntsync_obj_ioctl(struct file *file, unsigned int cmd,
switch (cmd) {
case NTSYNC_IOC_SEM_POST:
return ntsync_sem_post(obj, argp);
+ case NTSYNC_IOC_SEM_READ:
+ return ntsync_sem_read(obj, argp);
case NTSYNC_IOC_MUTEX_UNLOCK:
return ntsync_mutex_unlock(obj, argp);
case NTSYNC_IOC_MUTEX_KILL:
diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h
index 57721f5d31ba..e298400bf25a 100644
--- a/include/uapi/linux/ntsync.h
+++ b/include/uapi/linux/ntsync.h
@@ -55,5 +55,6 @@ struct ntsync_wait_args {
#define NTSYNC_IOC_EVENT_SET _IOR ('N', 0x88, __u32)
#define NTSYNC_IOC_EVENT_RESET _IOR ('N', 0x89, __u32)
#define NTSYNC_IOC_EVENT_PULSE _IOR ('N', 0x8a, __u32)
+#define NTSYNC_IOC_SEM_READ _IOR ('N', 0x8b, struct ntsync_sem_args)

#endif
--
2.43.0