[RFC]xf86-input-evdev: use libsysdev as build-time fallback if libudev is missing

[Peter Hutterer]

On Mon, Feb 02, 2015 at 05:35:50PM -0800, Isaac Dunham wrote:
> On Mon, Feb 02, 2015 at 05:30:14PM -0800, Isaac Dunham wrote:
> > Hello,
> > Having grown tired of hearing complaints about udev dependencies, I
> > wrote a library that does a very small subset of what libudev does with
> > a slightly more concise API. It does not care how /dev is managed.
> > The code may be found at:
> > github.com/idunham/libsysdev.git
> > 
> > I have ported xf86-input-evdev to use said library; the attached
> > patch will allow building with it as a compile-time fallback.
> > Does anyone have comments on this patch?
> > 
> > I'm aware that it would be possible to share much of the code by using
> > more #ifdef USE_UDEV; if that is better, I can adjust this.
> > 
> > Please note: I am *not* interested in arguing about udev, whether pro
> > or con. I'm just asking for a review of this patch.
> 
> Unfortuntely, I forgot the patch. My apologies.

short answer, and don't take it the wrong way please: not until we have a
couple of major distributions not providing libudev, which IMO is rather
unlikely. afaict the only selling point for non-libudev is for the BSDs but
then again that's not the only piece of the puzzle missing.

And even then I'd be easier to just ifdef out the code that relies on udev
rather than adding another library. sorry.

Cheers,
   Peter


> diff --git a/configure.ac b/configure.ac
> index 46f3dc7..6a56149 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -45,7 +45,19 @@ XORG_DEFAULT_OPTIONS
>  
>  # Obtain compiler/linker options from server and required extensions
>  PKG_CHECK_MODULES(XORG, [xorg-server >= 1.10] xproto inputproto)
> -PKG_CHECK_MODULES(UDEV, libudev)
> +PKG_CHECK_MODULES(UDEV, libudev, HAVE_UDEV="yes", HAVE_UDEV="no")
> +if test "x$HAVE_UDEV" = xyes; then
> +	AC_DEFINE(USE_UDEV, 1, [libudev available])
> +else 
> +	#fallback to libsysdev
> +	PKG_CHECK_MODULES(LIBSYSDEV, libsysdev, HAVE_SYSDEV="yes", HAVE_SYSDEV="no")
> +	if test "x$HAVE_SYSDEV" = xyes; then
> +		AC_DEFINE(USE_SYSDEV, 1, [libsysdev available])
> +	else
> +		echo "You must have either libudev or libsysdev installed!"
> +		exit 1
> +	fi
> +fi
>  
>  PKG_CHECK_MODULES(XI22, [inputproto >= 2.1.99.3] [xorg-server >= 1.11.99.901], HAVE_XI22="yes", HAVE_XI22="no")
>  PKG_CHECK_MODULES(LIBEVDEV, [libevdev >= 0.4])
> diff --git a/src/Makefile.am b/src/Makefile.am
> index 5e0c3b3..b8083a9 100644
> --- a/src/Makefile.am
> +++ b/src/Makefile.am
> @@ -30,7 +30,7 @@ AM_CPPFLAGS =-I$(top_srcdir)/include $(LIBEVDEV_CFLAGS)
>  
>  @DRIVER_NAME at _drv_la_LTLIBRARIES = @DRIVER_NAME at _drv.la
>  @DRIVER_NAME at _drv_la_LDFLAGS = -module -avoid-version
> - at DRIVER_NAME@_drv_la_LIBADD = $(MTDEV_LIBS) $(UDEV_LIBS) $(LIBEVDEV_LIBS)
> + at DRIVER_NAME@_drv_la_LIBADD = $(MTDEV_LIBS) $(UDEV_LIBS) $(LIBEVDEV_LIBS) $(LIBSYSDEV_LIBS)
>  @DRIVER_NAME at _drv_ladir = @inputdir@
>  
>  @DRIVER_NAME at _drv_la_SOURCES = @DRIVER_NAME at .c \
> diff --git a/src/evdev.c b/src/evdev.c
> index 2d99f07..965c885 100644
> --- a/src/evdev.c
> +++ b/src/evdev.c
> @@ -39,11 +39,17 @@
>  
>  #include <linux/version.h>
>  #include <sys/stat.h>
> -#include <libudev.h>
> +#include <sys/types.h>
>  #include <unistd.h>
>  #include <errno.h>
>  #include <fcntl.h>
>  
> +#ifdef USE_UDEV
> +#include <libudev.h>
> +#elif defined(USE_SYSDEV)
> +#include <libsysdev/sysdev.h>
> +#endif
> +
>  #include <xf86.h>
>  #include <xf86Xinput.h>
>  #include <exevents.h>
> @@ -231,6 +237,7 @@ EvdevIsDuplicate(InputInfoPtr pInfo)
>      return FALSE;
>  }
>  
> +#ifdef USE_UDEV
>  static BOOL
>  EvdevDeviceIsVirtual(const char* devicenode)
>  {
> @@ -265,6 +272,31 @@ out:
>      udev_unref(udev);
>      return rc;
>  }
> +#elif defined(USE_SYSDEV)
> +static BOOL
> +EvdevDeviceIsVirtual(const char* devicenode)
> +{
> +    struct stat st;
> +    int rc = FALSE;
> +    char *syspath;
> +    
> +    if (stat(devicenode, &st) == -1)
> +        goto out;
> +
> +    syspath = sysdev_getsyspath(major(st.st_rdev), minor(st.st_rdev),
> +    				S_ISCHR(st.st_mode));
> +
> +    if (syspath) {
> +        if (strstr(syspath, "LNXSYSTM"))
> +            rc = TRUE;
> +
> +	free(syspath);
> +    }
> +out:
> +    return rc;
> +}
> +#endif
> +
>  
>  #ifndef HAVE_SMOOTH_SCROLLING
>  static int wheel_up_button = 4;

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