[PATCH libevdev 1/2] uinput: use the UI_GET_SYSNAME ioctl if available

[Peter Hutterer]

On Thu, Jun 19, 2014 at 08:02:17PM -0400, Benjamin Tissoires wrote:
> On Thu, Jun 19, 2014 at 7:26 PM, Peter Hutterer
> <peter.hutterer at who-t.net> wrote:
> > Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
> > ---
> >  libevdev/libevdev-uinput.c | 12 ++++++++++--
> >  libevdev/libevdev-uinput.h | 17 +++++++----------
> >  2 files changed, 17 insertions(+), 12 deletions(-)
> >
> > diff --git a/libevdev/libevdev-uinput.c b/libevdev/libevdev-uinput.c
> > index e0ae31e..f8607d1 100644
> > --- a/libevdev/libevdev-uinput.c
> > +++ b/libevdev/libevdev-uinput.c
> > @@ -198,8 +198,17 @@ fetch_syspath_and_devnode(struct libevdev_uinput *uinput_dev)
> >  {
> >         struct dirent **namelist;
> >         int ndev, i;
> > +       int rc;
> > +       char buf[sizeof(SYS_INPUT_DIR) + 64] = SYS_INPUT_DIR;
> >
> > -       /* FIXME: use new ioctl() here once kernel supports it */
> > +       rc = ioctl(uinput_dev->fd,
> > +                  UI_GET_SYSNAME(sizeof(buf) - strlen(SYS_INPUT_DIR)),
> > +                  &buf[strlen(SYS_INPUT_DIR)]);
> > +       if (rc != -1) {
> > +               uinput_dev->syspath = strdup(buf);
> > +               uinput_dev->devnode = fetch_device_node(buf);
> > +               return 0;
> > +       }
> >
> >         ndev = scandir(SYS_INPUT_DIR, &namelist, is_input_device, alphasort);
> >         if (ndev <= 0)
> > @@ -207,7 +216,6 @@ fetch_syspath_and_devnode(struct libevdev_uinput *uinput_dev)
> >
> >         for (i = 0; i < ndev; i++) {
> >                 int fd, len;
> > -               char buf[sizeof(SYS_INPUT_DIR) + 64];
> >                 struct stat st;
> >
> >                 strcpy(buf, SYS_INPUT_DIR);
> > diff --git a/libevdev/libevdev-uinput.h b/libevdev/libevdev-uinput.h
> > index fa3eae7..f789711 100644
> > --- a/libevdev/libevdev-uinput.h
> > +++ b/libevdev/libevdev-uinput.h
> > @@ -176,17 +176,14 @@ int libevdev_uinput_get_fd(const struct libevdev_uinput *uinput_dev);
> >  /**
> >   * @ingroup uinput
> >   *
> > - * Return the syspath representing this uinput device.
> > - * At the time of writing, the uinput kernel device does not
> > - * provide a way to get the syspath directly through uinput so libevdev must guess.
> > - * In some cases libevdev is unable to derive the syspath. If the running kernel
> > - * supports the UI_GET_SYSNAME ioctl, the syspath is retrieved through that and will
> > - * be reliable and not be NULL. The UI_GET_SYSNAME ioctl is currently
> > - * scheduled for 3.15.
> > + * Return the syspath representing this uinput device. If the UI_GET_SYSNAME
> > + * ioctl not available, libevdev makes an educated guess.
> > + * The UI_GET_SYSNAME ioctl is available since Linux 3.15.
> >   *
> > - * @note This function may return NULL. libevdev currently uses ctime and
> > - * the device name to guess devices. To avoid false positives, wait at least
> > - * wait at least 1.5s between creating devices that have the same name.
> > + * @note This function may return NULL if UI_GET_SYSNAME is not available.
> > + * libevdev currently uses ctime and the device name to guess devices. To
> 
> Nitpick: "libevdev _therefore_ uses ctime and the device name to guess devices."

changed to "In that case, libevdev uses ctime..."
And dropped another "currently" in the libevdev_uinput_get_devnode() doc.

> Other than that:
> Reviewed-by: Benjamin Tissoires <benjamin.tissoires at gmail.com>

thanks, much appreciated

Cheers,
   Peter
> 
> > + * avoid false positives, wait at least wait at least 1.5s between creating
> > + * devices that have the same name.
> >   * @param uinput_dev A previously created uinput device.
> >   * @return The syspath for this device, including the preceding /sys
> >   *
> > --
> > 1.9.3
> >
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