Hi On Mon, Jul 15, 2013 at 3:37 PM, Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx> wrote: > Evemu [1] uses uinput to replay devices traces it has recorded. However, > the way evemu uses uinput is slightly different from how uinput is > supposed to be used. > Evemu creates the device node through uinput, bu inject events through > the input device node directly (and skipping the uinput node). > > Currently, evemu relies 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 the event node without > having to rely on this heuristic. It would actually be enough to return the "input_no" from input_register_device() (which is currently local but we could save it in "dev"). Or only the device-name. I don't know why you want the full syspath. It's just overhead in the kernel that we could easily let user-space do. And the path /sys/class/input/<devname> can be put together by user-space. Anyway, Dmitry has to decide on that. Apart from some style-issues I mentioned below: Reviewed-by: David Herrmann <dh.herrmann@xxxxxxxxx> Cheers David > [1] http://www.freedesktop.org/wiki/Evemu/ > > Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx> > --- > drivers/input/misc/uinput.c | 37 ++++++++++++++++++++++++++++++++++++- > include/linux/uinput.h | 1 + > include/uapi/linux/uinput.h | 3 +++ > 3 files changed, 40 insertions(+), 1 deletion(-) > > diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c > index 7d518b4..49a9f7d 100644 > --- a/drivers/input/misc/uinput.c > +++ b/drivers/input/misc/uinput.c > @@ -22,6 +22,7 @@ > * Changes/Revisions: > * 0.4 12/07/2013 (Peter Hutterer <peter.hutterer@xxxxxxxxxx>) > * - update uinput_user_dev struct to allow abs resolution > + * - add UI_GET_SYSPATH ioctl What tree is that patch against? I cannot see an "0.4" entry in: http://git.kernel.org/cgit/linux/kernel/git/dtor/input.git/tree/drivers/input/misc/uinput.c?h=next > * 0.3 09/04/2006 (Anssi Hannula <anssi.hannula@xxxxxxxxx>) > * - updated ff support for the changes in kernel interface > * - added MODULE_VERSION > @@ -667,6 +668,21 @@ static int uinput_ff_upload_from_user(const char __user *buffer, > __ret; \ > }) > > +static int uinput_str_to_user(const char *str, unsigned int maxlen, > + void __user *p) As Peter mentioned, I'd move "maxlen" to the end. > +{ > + int len; > + > + if (!str) > + return -ENOENT; > + > + len = strlen(str) + 1; > + if (len > maxlen) > + len = maxlen; > + > + return copy_to_user(p, str, len) ? -EFAULT : len; I'd prefer a "strlcpy()" so we guarantee a terminating 0 for user-space, but I guess that'd be rather complex to do here. I couldn't find any strlcpy_to_user()... > +} > + > static long uinput_ioctl_handler(struct file *file, unsigned int cmd, > unsigned long arg, void __user *p) > { > @@ -676,6 +692,8 @@ static long uinput_ioctl_handler(struct file *file, unsigned int cmd, > struct uinput_ff_erase ff_erase; > struct uinput_request *req; > char *phys; > + const char *path; > + unsigned int size; > > retval = mutex_lock_interruptible(&udev->mutex); > if (retval) > @@ -828,7 +846,24 @@ static long uinput_ioctl_handler(struct file *file, unsigned int cmd, > break; > > default: > - retval = -EINVAL; > + retval = -EAGAIN; > + } > + > + if (retval == -EAGAIN) { > + size = _IOC_SIZE(cmd); > + > + /* Now check variable-length commands */ > + switch (cmd & ~IOCSIZE_MASK) { > + case UI_GET_SYSPATH(0): > + path = kobject_get_path(&udev->dev->dev.kobj, > + GFP_KERNEL); I know, device registration is protected by udev->mutex but I'd still prefer: if (udev->state != UIST_CREATED) return -ENOENT; But that's probably a matter of taste. > + retval = uinput_str_to_user(path, size, p); > + kfree(path); > + break; > + > + default: > + retval = -EINVAL; > + } > } > > out: > diff --git a/include/linux/uinput.h b/include/linux/uinput.h > index 6291a22..64fab81 100644 > --- a/include/linux/uinput.h > +++ b/include/linux/uinput.h > @@ -22,6 +22,7 @@ > * Changes/Revisions: > * 0.4 12/07/2013 (Peter Hutterer <peter.hutterer@xxxxxxxxxx>) > * - update uinput_user_dev struct to allow abs resolution > + * - add UI_GET_SYSPATH ioctl > * 0.3 24/05/2006 (Anssi Hannula <anssi.hannulagmail.com>) > * - update ff support for the changes in kernel interface > * - add UINPUT_VERSION > diff --git a/include/uapi/linux/uinput.h b/include/uapi/linux/uinput.h > index f6a393b..d826409 100644 > --- a/include/uapi/linux/uinput.h > +++ b/include/uapi/linux/uinput.h > @@ -22,6 +22,7 @@ > * Changes/Revisions: > * 0.4 12/07/2013 (Peter Hutterer <peter.hutterer@xxxxxxxxxx>) > * - update uinput_user_dev struct to allow abs resolution > + * - add UI_GET_SYSPATH ioctl > * 0.3 24/05/2006 (Anssi Hannula <anssi.hannulagmail.com>) > * - update ff support for the changes in kernel interface > * - add UINPUT_VERSION > @@ -75,6 +76,8 @@ 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) > > +#define UI_GET_SYSPATH(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. > -- > 1.8.3.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
