On Sun, Mar 26, 2017 at 01:21:14PM -0300, Marcos Paulo de Souza wrote: > On Fri, Mar 24, 2017 at 02:39:13PM +1000, Peter Hutterer wrote: > > as usual, reading through these things multiple times means one spots a > > couple of different things. sorry about that. > > > > On Fri, Mar 24, 2017 at 12:34:59AM -0300, Marcos Paulo de Souza wrote: > > > Signed-off-by: Marcos Paulo de Souza <marcos.souza.org@xxxxxxxxx> > > > --- > > > Documentation/input/uinput.rst | 196 +++++++++++++++++++++++++++++++++++++++++ > > > 1 file changed, 196 insertions(+) > > > create mode 100644 Documentation/input/uinput.rst > > > > > > diff --git a/Documentation/input/uinput.rst b/Documentation/input/uinput.rst > > > new file mode 100644 > > > index 0000000..eb79b77 > > > --- /dev/null > > > +++ b/Documentation/input/uinput.rst > > > @@ -0,0 +1,196 @@ > > > +============= > > > +uinput module > > > +============= > > > + > > > +Introduction > > > +============ > > > + > > > +uinput is a kernel module that makes possible to create and handle input devices > > > > typo: makes *it* possible. > > > > replace "to create and handle" with "to emulate", the rest is in the next > > sentence anyway > > Fixed. > > > > > > +from userspace. By writing to the module's /dev/uinput (or /dev/input/uinput), a > > > +process can create a virtual device with specific capabilities. > > > +Once created, the process can send events through that virtual device. > > > + > > > +Interface > > > +========= > > > + > > > +:: > > > + > > > + linux/uinput.h > > > + > > > +The uinput header defines ioctls to create, setup and destroy virtual devices. > > > + > > > +libevdev > > > +======== > > > + > > > +libevdev is a wrapper library for evdev devices, making uinput setup easier > > > +by skipping a lot of ioctl calls. When dealing with uinput, libevdev is the best > > > +alternative over accessing uinput directly, and it is less error prone. > > > > "libevdev is a wrapper library for evdev devices that provides interfaces to > > create uinput devices and send events. libevdev is less error-prone than > > accessing uinput directly and should be considered for new software". > > Much better. Fixed. > > > > > > + > > > +For examples and more information about libevdev: > > > +https://cgit.freedesktop.org/libevdev > > > + > > > > Please use https://www.freedesktop.org/software/libevdev/doc/latest/ > > (which needs a link to the git repo, I'll fix that in a minute) > > Fixed. > > > > > > +Examples > > > +======== > > > + > > > +1.0 Keyboard events > > > +------------------- > > > + > > > +This first example shows how to create a new virtual device and how to send a > > > +key event. 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; > > > + > > > + ie.type = type; > > > + ie.code = code; > > > + ie.value = val; > > > + /* below timestamp values are ignored */ > > > + ie.time.tv_sec = 0; > > > + ie.time.tv_usec = 0; > > > + > > > + write(fd, &ie, sizeof(ie)); > > > + } > > > + > > > + int main() { > > > + struct uinput_setup usetup; > > > + > > > + fd = open("/dev/uinput", O_WRONLY | O_NONBLOCK); > > > + > > > + /* the ioctls below enables the to be created device to key > > > + * events, in this case the space key > > > + **/ > > > > the comment terminator doesn't look right > > Fixed. > > > > > > + ioctl(fd, UI_SET_EVBIT, EV_KEY); > > > + ioctl(fd, UI_SET_KEYBIT, KEY_SPACE); > > > + > > > + memset(&usetup, 0, sizeof(usetup)); > > > + usetup.id.bustype = BUS_USB; > > > + usetup.id.vendor = 0x1234; /* sample vendor */ > > > > add a sample product id too please > Added. > > > > > > + strcpy(usetup.name, "Example device"); > > > + > > > + ioctl(fd, UI_DEV_SETUP, &usetup); > > > + ioctl(fd, UI_DEV_CREATE); > > > + > > > + /* UI_DEV_CREATE causes the kernel to create the device nodes for this > > > > "On UI_DEV_CREATE the kernel creates the device nodes..." > Fixed. > > > > > > + * device. Insert a pause so that userspace has time to detect, > > > + * initialize the new device, and can start to listen to events from > > > + * this device > > > + **/ > > > > the comment terminator doesn't look right > > > > note: the actual pause is missing now :) > > I thought you wanted just the warning, but ok, I added back the sleep > call :) better to have something that can be copy-pasted and works than expecting people to add misc bits. > > > + > > > + /* 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); > > > > come to think of it, you probably need a pause here too, iirc a caller may > > get ENODEV before reading the key events otherwise. > > We need a sleep call after each emitted event? no, I think we need a sleep between the final emit and the UI_DEV_DESTROY, otherwise those events may not get delivered (not 100% sure). Cheers, Peter > > > > > > + > > > + ioctl(fd, UI_DEV_DESTROY); > > > + close(fd); > > > + > > > + return 0; > > > + } > > > + > > > +2.0 Mouse movements > > > +------------------- > > > + > > > +This example shows how to create a virtual device that behaves like a physical > > > +mouse. > > > + > > > +.. code-block:: c > > > + > > > + #include <linux/uinput.h> > > > + > > > + /* emit function is identical to of the first example */ > > > + > > > + struct uinput_setup usetup; > > > + int i = 50; > > > + > > > + fd = open("/dev/uinput", O_WRONLY | O_NONBLOCK); > > > + > > > + /* enable mouse button left and relative events */ > > > + ioctl(fd, UI_SET_EVBIT, EV_KEY); > > > + ioctl(fd, UI_SET_KEYBIT, BTN_LEFT); > > > + > > > + ioctl(fd, UI_SET_EVBIT, EV_REL); > > > + ioctl(fd, UI_SET_RELBIT, REL_X); > > > + ioctl(fd, UI_SET_RELBIT, REL_Y); > > > + > > > + memset(&usetup, 0, sizeof(usetup)); > > > + usetup.id.bustype = BUS_USB; > > > + usetup.id.vendor = 0x1234; /* sample vendor */ > > > + strcpy(usetup.name, "Example device"); > > > + > > > + ioctl(fd, UI_DEV_SETUP, &usetup); > > > + ioctl(fd, UI_DEV_CREATE); > > > + > > > + /* UI_DEV_CREATE causes the kernel to create the device nodes for this > > > + * device. Insert a pause so that userspace has time to detect, > > > + * initialize the new device, and can start to listen to events from > > > + * this device > > > + **/ > > > + > > > + /* moves the mouse diagonally, 5 units per axis */ > > > + while (i--) { > > > + emit(EV_REL, REL_X, 5); > > > + emit(EV_REL, REL_Y, 5); > > > + emit(EV_SYN, SYN_REPORT, 0); > > > + usleep(15000); > > > + } > > > + > > > + ioctl(fd, UI_DEV_DESTROY); > > > + close(fd); > > > + > > > + 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. > > > > I think this should really include the version check. > > Uhg, I forgot this one again. Fixed here. > > Sending a new version soon. > > > > > Cheers, > > Peter > > > > > + > > > +.. code-block:: c > > > + > > > + #include <linux/uinput.h> > > > + > > > + /* emit function is identical to of the first example */ > > > + > > > + struct uinput_user_dev uud; > > > + > > > + fd = open("/dev/uinput", O_WRONLY | O_NONBLOCK); > > > + > > > + /* the ioctls below enables the to be created device to key > > > + * events, in this case the space key > > > + **/ > > > + ioctl(fd, UI_SET_EVBIT, EV_KEY); > > > + ioctl(fd, UI_SET_KEYBIT, KEY_SPACE); > > > + > > > + memset(&uud, 0, sizeof(uud)); > > > + snprintf(uud.name, UINPUT_MAX_NAME_SIZE, "uinput old interface"); > > > + write(fd, &uud, sizeof(uud)); > > > + > > > + ioctl(fd, UI_DEV_CREATE); > > > + > > > + /* UI_DEV_CREATE causes the kernel to create the device nodes for this > > > + * device. Insert a pause so that userspace has time to detect, > > > + * initialize the new device, and can start to listen to events from > > > + * this device > > > + **/ > > > + > > > + /* 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); > > > + > > > + ioctl(fd, UI_DEV_DESTROY); > > > + close(fd); > > > + > > > + return 0; > > > + > > > -- > > > 2.9.3 > > > > > -- > Thanks, > Marcos -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
