Signed-off-by: Marcos Paulo de Souza <marcos.souza....@gmail.com>
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+=============
+uinput module
+=============
+
+Introduction
+============
+
+uinput is a kernel module that makes possible create and handle input devices
from userspace. By using /dev/uinput (or /dev/input/uinput), a process can
create virtual devices and emit events like key pressing, mouse movements and
joystick buttons.
+
+Interface
+=========
+
+::
+
+ linux/uinput.h
+
+The uinput header defines ioctl request keys to create, setup and destroy
virtual devices, along with ioctls specific to uinput devices, like enabling
events and keys to be send to the kernel.
+
+Examples
+========
+
+1.0 Keyboard events
+-------------------
+
+This first example shows how to create a new virtual device and how to send a
key event as well as a physical keyboard. All default imports and error
handlers were removed for the sake of simplicity.
+
+.. code-block:: c
+
+ #include <linux/uinput.h>
+
+ int fd;
+
+ void emit(int type, int code, int val)
+ {
+ struct input_event ie;
+ memset(&ie, 0, sizeof(ie));
+ ie.type = type;
+ ie.code = code;
+ ie.value = val;
+
+ if (write(fd, &ie, sizeof(ie)) < 0) {
+ perror("write2");
+ exit(1);
+ }
+ }
+
+ int main() {
+ struct input_id uid;
+ struct uinput_setup usetup;
+
+ fd = open("/dev/uinput", O_WRONLY | O_NONBLOCK);
+ ioctl(fd, UI_SET_EVBIT, EV_KEY);
+ ioctl(fd, UI_SET_KEYBIT, KEY_SPACE);
+
+ memset(&uid, 0, sizeof(iod));
+ memset(&usetup, 0, sizeof(usetup));
+ usetup.id = uid;
+ strcpy(usetup.name, "ex_device");
+
+ ioctl(fd, UI_DEV_SETUP, &usetup);
+ ioctl(fd, UI_DEV_CREATE);
+
+ /* wait some time until the Window Manager can get the reference for
the
+ * new virtual device to receive data from
+ * */
+ sleep(1);
+
+ /* send key press, report the event, send key release, and report
again */
+ emit(EV_KEY, KEY_SPACE, 1);
+ emit(EV_SYN, SYN_REPORT, 0);
+ emit(EV_KEY, KEY_SPACE, 0);
+ emit(EV_SYN, SYN_REPORT, 0);
+
+ close(fd);
+
+ return 0;
+ }
+
+2.0 Mouse movements
+-------------------
+
+This example shows how to create a virtual device who behaves like a physical
mouse.
+
+.. code-block:: c
+
+ int i = 50;
+
+ /* emit function is the same of the example above */
+
+ void emit_rel(int code, int val, int syn)
+ {
+ emit(EV_REL, code, val);
+ if (syn)
+ emit(EV_SYN, SYN_REPORT, 0);
+ }
+
+ /* ...open uinput file as shown in the previous example... */
+
+ /* enable mouse button left and relative events. This makes the Window
Manager to interpret this
+ * device as a physical mouse
+ */
+ if (ioctl(fd, UI_SET_EVBIT, EV_KEY) == -1) {
+ perror("ioctl0");
+ exit(1);
+ }
+
+ if (ioctl(fd, UI_SET_KEYBIT, BTN_LEFT) == -1) {
+ perror("ioctl0.1");
+ exit(1);
+ }
+
+ if (ioctl(fd, UI_SET_EVBIT, EV_REL) == -1) {
+ perror("ioctl1");
+ exit(1);
+ }
+
+ if (ioctl(fd, UI_SET_RELBIT, REL_X) == -1) {
+ perror("ioctl2");
+ exit(1);
+ }
+
+ if (ioctl(fd, UI_SET_RELBIT, REL_Y) == -1) {
+ perror("ioctl3");
+ exit(1);
+ }
+
+ /* ...device setup, device create... */
+
+ /* Give some time for the Window Manager to get events of the new virtual
device */
+ sleep(1);
+
+ /* moves the mouse diagonally, 5 units per axis */
+ while (i--) {
+ emit_rel(REL_X, 5, 0);
+ emit_rel(REL_Y, 5, 1);
+ usleep(15000);
+ }
+
+ /* device destroy, device close */
+ return 0;
+
+3.0 uinput old interface
+------------------------
+
+Before kernel 4.5, uinput didn't have an ioctl to setup a virtual device. When
running a version prior to 4.5, the user needs to fill a different struct and
call write on the uinput file descriptor.
+
+.. code-block:: c
+
+ /* add include of uinput header */
+ struct uinput_user_dev uud;
+
+ /* open uinput device, and set the proper events */
+
+ memset(&uud, 0 sizeof(uud));
+ snprintf(uud.name, UINPUT_MAX_NAME_SIZE, "uinput_old_style");
+ write(fd, &uud, sizeof(uud));
+
+ /* call DEV_CREATE ioctl, and emit the events */
--
2.9.3
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