Input: uinput - add UI_GET_SYSNAME ioctl to retrieve the sysfs path

uinput is used in the xorg-integration-tests suite and in the wayland
test suite. These automated tests suites create many virtual input
devices and then hook something to read these newly created devices.

Currently, uinput does not provide the created input device, which means
that we rely on an heuristic to guess which input node was created.
The problem is that is heuristic is subjected to races between different
uinput devices or even with physical devices. Having a way to retrieve
the sysfs path allows us to find without any doubts the event node.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

1 files changed, 12 insertions, 1 deletions

diff --git a/include/uapi/linux/uinput.h b/include/uapi/linux/uinput.h
index fe46431593f9..0389b489bbba 100644
--- a/include/uapi/linux/uinput.h
+++ b/include/uapi/linux/uinput.h
@@ -20,6 +20,8 @@
  * Author: Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org>
  *
  * Changes/Revisions:
+ *      0.4     01/09/2014 (Benjamin Tissoires <benjamin.tissoires@redhat.com>)
+ *              - add UI_GET_SYSNAME ioctl
  *      0.3     24/05/2006 (Anssi Hannula <anssi.hannulagmail.com>)
  *              - update ff support for the changes in kernel interface
  *              - add UINPUT_VERSION
@@ -35,7 +37,7 @@
 #include <linux/types.h>
 #include <linux/input.h>
 
-#define UINPUT_VERSION          3
+#define UINPUT_VERSION          4
 
 
 struct uinput_ff_upload {
@@ -73,6 +75,15 @@ struct uinput_ff_erase {
 #define UI_BEGIN_FF_ERASE       _IOWR(UINPUT_IOCTL_BASE, 202, struct uinput_ff_erase)
 #define UI_END_FF_ERASE         _IOW(UINPUT_IOCTL_BASE, 203, struct uinput_ff_erase)
 
+/**
+ * UI_GET_SYSNAME - get the sysfs name of the created uinput device
+ *
+ * @return the sysfs name of the created virtual input device.
+ * The complete sysfs path is then /sys/devices/virtual/input/--NAME--
+ * Usually, it is in the form "inputN"
+ */
+#define UI_GET_SYSNAME(len)     _IOC(_IOC_READ, UINPUT_IOCTL_BASE, 300, len)
+
 /*
  * To write a force-feedback-capable driver, the upload_effect
  * and erase_effect callbacks in input_dev must be implemented.