On Fri, Jun 20, 2014 at 01:26:40PM +0200, David Herrmann wrote:
> This adds a new ioctl UINPUT_DEV_SETUP that replaces the old device setup
> method (by write()'ing "struct uinput_user_dev" to the node). The old
> method is not easily extendable and requires huge payloads. Furthermore,
> overloading write() without properly versioned objects is error-prone.
>
> Therefore, we introduce a new ioctl to replace the old method. The ioctl
> supports all features of the old method, plus a "resolution" field for
> absinfo. Furthermore, it's properly forward-compatible to new ABS codes
> and a growing "struct input_absinfo" structure.
>
> The ioctl also allows user-space to skip unknown axes if not set. The
> payload-size can now be specified by the caller. There is no need to copy
> the whole array temporarily into the kernel, but instead we can iterate
> over it and copy each value manually.
>
> Signed-off-by: David Herrmann <dh.herrmann@xxxxxxxxx>
> ---
> v2:
> - drop "version" field
> - drop "size" field
> - only copy absinfo if UI_SET_ABSBIT was called for the axis
> - minor linguistic changes
>
> drivers/input/misc/uinput.c | 67 +++++++++++++++++++++++++++++++++++++++++++--
> include/uapi/linux/uinput.h | 55 +++++++++++++++++++++++++++++++++++--
> 2 files changed, 116 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c
> index a2a3895..5c125e8 100644
> --- a/drivers/input/misc/uinput.c
> +++ b/drivers/input/misc/uinput.c
> @@ -371,8 +371,65 @@ static int uinput_allocate_device(struct uinput_device *udev)
> return 0;
> }
>
> -static int uinput_setup_device(struct uinput_device *udev,
> - const char __user *buffer, size_t count)
> +static int uinput_dev_setup(struct uinput_device *udev,
> + struct uinput_setup __user *arg)
> +{
> + struct uinput_setup setup;
> + struct input_dev *dev;
> + int i, retval;
don't you want to a check for udev->state != UIST_CREATED here?
> +
> + if (copy_from_user(&setup, arg, sizeof(setup)))
> + return -EFAULT;
> + if (!setup.name[0])
> + return -EINVAL;
> + /* So far we only support the original "struct input_absinfo", but be
> + * forward compatible and allow larger payloads. */
> + if (setup.absinfo_size < sizeof(struct input_absinfo))
> + return -EINVAL;
> +
> + dev = udev->dev;
> + dev->id = setup.id;
> + udev->ff_effects_max = setup.ff_effects_max;
> +
> + kfree(dev->name);
> + dev->name = kstrndup(setup.name, UINPUT_MAX_NAME_SIZE, GFP_KERNEL);
> + if (!dev->name)
> + return -ENOMEM;
> +
> + if (setup.abs_cnt > ABS_CNT)
> + setup.abs_cnt = ABS_CNT;
> +
> + if (setup.abs_cnt > 0) {
> + u8 __user *p = (u8 __user*)arg->abs;
> +
> + input_alloc_absinfo(dev);
> + if (!dev->absinfo)
> + return -ENOMEM;
> +
> + for (i = 0; i < setup.abs_cnt; ++i, p += setup.absinfo_size) {
> + struct input_absinfo absinfo;
> +
> + if (!test_bit(i, dev->absbit))
> + continue;
> +
> + if (copy_from_user(&absinfo, p, sizeof(absinfo)))
> + return -EFAULT;
> +
> + dev->absinfo[i] = absinfo;
> + }
> + }
> +
> + retval = uinput_validate_absbits(dev);
> + if (retval < 0)
> + return retval;
> +
> + udev->state = UIST_SETUP_COMPLETE;
> + return 0;
> +}
> +
> +/* legacy setup via write() */
> +static int uinput_setup_device_legacy(struct uinput_device *udev,
> + const char __user *buffer, size_t count)
> {
> struct uinput_user_dev *user_dev;
> struct input_dev *dev;
> @@ -475,7 +532,7 @@ static ssize_t uinput_write(struct file *file, const char __user *buffer,
>
> retval = udev->state == UIST_CREATED ?
> uinput_inject_events(udev, buffer, count) :
> - uinput_setup_device(udev, buffer, count);
> + uinput_setup_device_legacy(udev, buffer, count);
>
> mutex_unlock(&udev->mutex);
>
> @@ -736,6 +793,10 @@ static long uinput_ioctl_handler(struct file *file, unsigned int cmd,
> uinput_destroy_device(udev);
> goto out;
>
> + case UI_DEV_SETUP:
> + retval = uinput_dev_setup(udev, p);
> + goto out;
> +
> case UI_SET_EVBIT:
> retval = uinput_set_bit(arg, evbit, EV_MAX);
> goto out;
> diff --git a/include/uapi/linux/uinput.h b/include/uapi/linux/uinput.h
> index 19339cf..982144d 100644
> --- a/include/uapi/linux/uinput.h
> +++ b/include/uapi/linux/uinput.h
> @@ -20,6 +20,8 @@
> * Author: Aristeu Sergio Rozanski Filho <aris@xxxxxxxxxxxxxxxxx>
> *
> * Changes/Revisions:
> + * 5 06/20/2014 (David Herrmann <dh.herrmann@xxxxxxxxx>
> + * - add UI_DEV_SETUP ioctl
> * 0.4 01/09/2014 (Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>)
> * - add UI_GET_SYSNAME ioctl
> * 0.3 24/05/2006 (Anssi Hannula <anssi.hannulagmail.com>)
hm, I think you misunderstood my comment. I was hoping to fix all up in one
go, I had noticed that the others were 0.x as well :)
With the extra check, both patches Reviewed-by: Peter Hutterer <peter.hutterer@xxxxxxxxx>
Cheers,
Peter
> @@ -37,8 +39,8 @@
> #include <linux/types.h>
> #include <linux/input.h>
>
> -#define UINPUT_VERSION 4
> -
> +#define UINPUT_VERSION 5
> +#define UINPUT_MAX_NAME_SIZE 80
>
> struct uinput_ff_upload {
> __u32 request_id;
> @@ -93,6 +95,54 @@ struct uinput_ff_erase {
> */
> #define UI_GET_VERSION _IOR(UINPUT_IOCTL_BASE, 301, unsigned int)
>
> +struct uinput_setup {
> + __u64 absinfo_size;
> + struct input_id id;
> + char name[UINPUT_MAX_NAME_SIZE];
> + __u32 ff_effects_max;
> + __u32 abs_cnt;
> + struct input_absinfo abs[];
> +};
> +
> +/**
> + * UI_DEV_SETUP - Set device parameters for setup
> + *
> + * This ioctl sets parameters for the input-device to be created. It must be
> + * issued *before* calling UI_DEV_CREATE or it will fail. This ioctl supersedes
> + * the old "struct uinput_user_dev" method, which wrote this data via write().
> + *
> + * This ioctl takes a "struct uinput_setup" object as argument. The fields of
> + * this object are as follows:
> + * absinfo_size: This field *must* be initialized to
> + * "sizeof(struct input_absinfo)". It allows to extend the API
> + * to support more absinfo fields. Older kernels ignore unknown
> + * extensions to "struct input_absinfo".
> + * id: See the description of "struct input_id". This field is
> + * copied unchanged into the new device.
> + * name: This is used unchanged as name for the new device.
> + * ff_effects_max: This limits the maximum numbers of force-feedback effects.
> + * See below for a description of FF with uinput.
> + * abs_cnt: This field defines the amount of elements in the following
> + * "abs" array. Axes beyond the kernel's ABS_CNT are ignored.
> + * abs: This is an appended array that contains parameters for ABS
> + * axes. See "struct input_absinfo" for a description of these
> + * fields. This array is copied unchanged into the kernel for
> + * all specified axes. Axes not enabled via UI_SET_ABSBIT are
> + * ignored.
> + *
> + * This ioctl can be called multiple times and will overwrite previous values.
> + * If this ioctl fails with -EINVAL, you're recommended to use the old
> + * "uinput_user_dev" method via write() as fallback, in case you run on an old
> + * kernel that does not support this ioctl.
> + *
> + * This ioctl may fail with -EINVAL if it is not supported or if you passed
> + * incorrect values, -ENOMEM if the kernel runs out of memory or -EFAULT if the
> + * passed uinput_setup object cannot be read/written.
> + * If this call fails, partial data may have already been applied to the
> + * internal device.
> + */
> +#define UI_DEV_SETUP _IOWR(UINPUT_IOCTL_BASE, 302, struct uinput_setup)
> +
> /*
> * To write a force-feedback-capable driver, the upload_effect
> * and erase_effect callbacks in input_dev must be implemented.
> @@ -144,7 +194,6 @@ struct uinput_ff_erase {
> #define UI_FF_UPLOAD 1
> #define UI_FF_ERASE 2
>
> -#define UINPUT_MAX_NAME_SIZE 80
> struct uinput_user_dev {
> char name[UINPUT_MAX_NAME_SIZE];
> struct input_id id;
> --
> 2.0.0
>
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