udev: Add builtin/rule to export evdev information as udev properties

[elogind.git] / src / udev / udev-builtin-evdev_id.c

diff --git a/src/udev/udev-builtin-evdev_id.c b/src/udev/udev-builtin-evdev_id.c
new file mode 100644 (file)
index 0000000..1b58bdd
--- /dev/null
+++ b/src/udev/udev-builtin-evdev_id.c
@@ -0,0 +1,78 @@
+/*
+ * evdev_id - extracts miscellaneous information from evdev devices
+ *
+ * Copyright (C) 2014 Red Hat
+ * Author:
+ *   Carlos Garnacho  <carlosg@gnome.org>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with keymap; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#include <linux/input.h>
+#include "udev.h"
+#include "util.h"
+
+static inline int abs_size_mm(const struct input_absinfo *absinfo) {
+        /* Resolution is defined to be in units/mm for ABS_X/Y */
+        return (absinfo->maximum - absinfo->minimum) / absinfo->resolution;
+}
+
+static void extract_info(struct udev_device *dev, const char *devpath, bool test) {
+        char width[DECIMAL_STR_MAX(int)], height[DECIMAL_STR_MAX(int)];
+        struct input_absinfo xabsinfo = {}, yabsinfo = {};
+        _cleanup_close_ int fd = -1;
+
+        fd = open(devpath, O_RDONLY|O_CLOEXEC);
+        if (fd < 0)
+                return;
+
+        if (ioctl(fd, EVIOCGABS(ABS_X), &xabsinfo) < 0 ||
+            ioctl(fd, EVIOCGABS(ABS_Y), &yabsinfo) < 0)
+                return;
+
+        if (xabsinfo.resolution <= 0 || yabsinfo.resolution <= 0)
+                return;
+
+        snprintf(width, sizeof(width), "%d", abs_size_mm(&xabsinfo));
+        snprintf(height, sizeof(height), "%d", abs_size_mm(&yabsinfo));
+
+        udev_builtin_add_property(dev, test, "ID_INPUT_WIDTH_MM", width);
+        udev_builtin_add_property(dev, test, "ID_INPUT_HEIGHT_MM", height);
+}
+
+static int builtin_evdev_id(struct udev_device *dev, int argc, char *argv[], bool test) {
+        const char *subsystem;
+        const char *devnode;
+
+        subsystem = udev_device_get_subsystem(dev);
+
+        if (!subsystem || !streq(subsystem, "input"))
+                return EXIT_SUCCESS;
+
+        devnode = udev_device_get_devnode(dev);
+        /* not an evdev node */
+        if (!devnode)
+                return EXIT_SUCCESS;
+
+        extract_info(dev, devnode, test);
+
+        return EXIT_SUCCESS;
+}
+
+const struct udev_builtin udev_builtin_evdev_id = {
+        .name = "evdev_id",
+        .cmd = builtin_evdev_id,
+        .help = "evdev devices information",
+};