Back off if we detect a vmmouse kernel driver v3

If a vmmouse kernel driver is active, vmmouse input is handled by the Xorg
evdev driver and not by the vmmouse driver, so make sure the vmmouse_detect
utility doesn't detect a vmmouse if a kernel driver is active.

v2: Change the vmmouse kernel device name, fix comment.
v3: Fix up libudev error handling.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>

1 files changed, 104 insertions, 0 deletions

diff --git a/tools/vmmouse_udev.c b/tools/vmmouse_udev.c
new file mode 100644
index 0000000..dc100ae
--- /dev/null
+++ b/tools/vmmouse_udev.c
@@ -0,0 +1,104 @@
+/*
+ * Copyright 2014 by VMware, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Except as contained in this notice, the name of the copyright holder(s)
+ * and author(s) shall not be used in advertising or otherwise to promote
+ * the sale, use or other dealings in this Software without prior written
+ * authorization from the copyright holder(s) and author(s).
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#ifdef HAVE_LIBUDEV
+#include <libudev.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define KERNEL_DEVNAME "VirtualPS/2 VMware VMMouse"
+
+/**
+ * vmmouse_uses_kernel_driver - Check whether there's an active
+ *    vmmouse driver in the kernel.
+ *
+ * Returns 0 if there was no kernel driver found.
+ * Returns non-zero on error or if there was an active driver found.
+ *
+ * Scans the input subsystem for devices matching KERNEL_DEVNAME. These
+ * devices are assumed to be active vmmouse drivers.
+ */
+int vmmouse_uses_kernel_driver(void)
+{
+    struct udev *udev;
+    struct udev_enumerate *enumerate;
+    struct udev_list_entry *devices, *dev_list_entry;
+    struct udev_device *dev;
+
+    udev = udev_new();
+    if (!udev)
+	return 1;
+
+    /*
+     * Udev error return codes that are not caught immediately are
+     * typically caught in the input argument check in the udev
+     * function calls following the failing call!
+     */
+    enumerate = udev_enumerate_new(udev);
+    if (udev_enumerate_add_match_subsystem(enumerate, "input"))
+	goto out_err;
+    if (udev_enumerate_scan_devices(enumerate))
+	goto out_err;
+
+    devices = udev_enumerate_get_list_entry(enumerate);
+    udev_list_entry_foreach(dev_list_entry, devices) {
+	const char *path, *name;
+
+	path = udev_list_entry_get_name(dev_list_entry);
+	dev = udev_device_new_from_syspath(udev, path);
+	if (!dev)
+	    goto out_err;
+	name = udev_device_get_sysattr_value(dev, "name");
+	if (name && !strcasecmp(name, KERNEL_DEVNAME))
+	    goto out_found;
+
+	udev_device_unref(dev);
+    }
+
+    udev_enumerate_unref(enumerate);
+    udev_unref(udev);
+
+    return 0;
+
+  out_found:
+    udev_device_unref(dev);
+  out_err:
+    udev_enumerate_unref(enumerate);
+    udev_unref(udev);
+
+    return 1;
+}
+#else
+int vmmouse_uses_kernel_driver(void)
+{
+   return 0;
+}
+#endif