[PATCH 05/16] HID: uhid: implement write() on uhid devices
From: David Herrmann <hidden>
Date: 2012-06-10 13:16:45
Subsystem:
hid core layer, the rest, uhid userspace hid io driver · Maintainers:
Jiri Kosina, Benjamin Tissoires, Linus Torvalds, David Rheinsberg
Similar to read() you can only write() a single event with one call to an uhid device. To write multiple events use writev() which is supported by uhid. We currently always return -EOPNOTSUPP but other events will be added in later patches. Signed-off-by: David Herrmann <redacted> --- drivers/hid/uhid.c | 31 ++++++++++++++++++++++++++++++- 1 file changed, 30 insertions(+), 1 deletion(-)
diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c
index 9386082..31e8379 100644
--- a/drivers/hid/uhid.c
+++ b/drivers/hid/uhid.c@@ -30,6 +30,7 @@ struct uhid_device { struct mutex devlock; struct hid_device *hid; + struct uhid_event input_buf; wait_queue_head_t waitq; spinlock_t qlock;
@@ -156,7 +157,35 @@ try_again: static ssize_t uhid_char_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos) { - return 0; + struct uhid_device *uhid = file->private_data; + int ret; + size_t len; + + /* we need at least the "type" member of uhid_event */ + if (count < sizeof(__u32)) + return -EINVAL; + + ret = mutex_lock_interruptible(&uhid->devlock); + if (ret) + return ret; + + memset(&uhid->input_buf, 0, sizeof(uhid->input_buf)); + len = min(count, sizeof(uhid->input_buf)); + if (copy_from_user(&uhid->input_buf, buffer, len)) { + ret = -EFAULT; + goto unlock; + } + + switch (uhid->input_buf.type) { + default: + ret = -EOPNOTSUPP; + } + +unlock: + mutex_unlock(&uhid->devlock); + + /* return "count" not "len" to not confuse the caller */ + return ret ? ret : count; } static unsigned int uhid_char_poll(struct file *file, poll_table *wait)
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1.7.10.4