Use a new "Virtual Device" boolean property to mark virtual devices

Use udev to check for the device's sysfs path, if it contains LNXSYSTM it's
a kernel-emulated device. This property can then be used to determine if
there are any real devices connected, allowing the desktop environment to
e.g. turn off the touchpad whenever there's a mouse attached.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

1 files changed, 69 insertions, 0 deletions

diff --git a/src/udev.c b/src/udev.c
new file mode 100644
index 0000000..9570d8f
--- /dev/null
+++ b/src/udev.c
@@ -0,0 +1,69 @@
+/*
+ * Copyright © 2011 Red Hat, Inc.
+ *
+ * Permission to use, copy, modify, distribute, and sell this software
+ * and its documentation for any purpose is hereby granted without
+ * fee, provided that the above copyright notice appear in all copies
+ * and that both that copyright notice and this permission notice
+ * appear in supporting documentation, and that the name of Red Hat
+ * not be used in advertising or publicity pertaining to distribution
+ * of the software without specific, written prior permission.  Red
+ * Hat makes no representations about the suitability of this software
+ * for any purpose.  It is provided "as is" without express or implied
+ * warranty.
+ *
+ * THE AUTHORS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN
+ * NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+ * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
+ * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Authors:
+ *	Peter Hutterer (peter.hutterer@redhat.com)
+ */
+
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "evdev.h"
+
+#include <libudev.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+Bool
+udev_device_is_virtual(const char* devicenode)
+{
+    struct udev *udev = NULL;
+    struct udev_device *device = NULL;
+    struct stat st;
+    int rc = FALSE;
+    const char *devpath;
+
+    udev = udev_new();
+    if (!udev)
+        goto out;
+
+    stat(devicenode, &st);
+    device = udev_device_new_from_devnum(udev, 'c', st.st_rdev);
+
+    if (!device)
+        goto out;
+
+
+    devpath = udev_device_get_devpath(device);
+    if (!devpath)
+        goto out;
+
+    if (strstr(devpath, "LNXSYSTM"))
+        rc = TRUE;
+
+out:
+    udev_device_unref(device);
+    udev_unref(udev);
+    return rc;
+}