tools: libinput-record: record the hid report descriptor where available

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

tools/libinput-record-verify-yaml.py

@@ -140,6 +140,15 @@ def test_evdev_properties(self):
             properties = evdev['properties']
             self.assertTrue(isinstance(properties, list))
 
+    def test_hid(self):
+        devices = self.yaml['devices']
+        for d in devices:
+            hid = d['hid']
+            self.assertTrue(isinstance(hid, list))
+            for byte in hid:
+                self.assertGreaterEqual(byte, 0)
+                self.assertLessEqual(byte, 255)
+
     def test_udev_sections_exist(self):
         sections = ['properties']
         devices = self.yaml['devices']

tools/libinput-record.c

@@ -1614,6 +1614,52 @@ print_evdev_description(struct record_context *ctx, struct record_device *dev)
 	indent_pop(ctx);
 }
 
+static inline void
+print_hid_report_descriptor(struct record_context *ctx,
+			    struct record_device *dev)
+{
+	const char *prefix = "/dev/input/event";
+	const char *node;
+	char syspath[PATH_MAX];
+	unsigned char buf[1024];
+	int len;
+	int fd;
+	bool first = true;
+
+	/* we take the shortcut rather than the proper udev approach, the
+	   report_descriptor is available in sysfs and two devices up from
+	   our device. 2 digits for the event number should be enough.
+	   This approach won't work for /dev/input/by-id devices. */
+	if (!strneq(dev->devnode, prefix, strlen(prefix)) ||
+	    strlen(dev->devnode) > strlen(prefix) + 2)
+		return;
+
+	node = &dev->devnode[strlen(prefix)];
+	len = snprintf(syspath,
+		       sizeof(syspath),
+		       "/sys/class/input/event%s/device/device/report_descriptor",
+		       node);
+	if (len < 55 || len > 56)
+		return;
+
+	fd = open(syspath, O_RDONLY);
+	if (fd == -1)
+		return;
+
+	iprintf(ctx, "hid: [");
+
+	while ((len = read(fd, buf, sizeof(buf))) > 0) {
+		for (int i = 0; i < len; i++) {
+			/* YAML requires decimal */
+			noiprintf(ctx, "%s%u",first ? "" : ", ", buf[i]);
+			first = false;
+		}
+	}
+	noiprintf(ctx, " ]\n");
+
+	close(fd);
+}
+
 static inline void
 print_udev_properties(struct record_context *ctx, struct record_device *dev)
 {
@@ -1778,6 +1824,7 @@ print_device_description(struct record_context *ctx, struct record_device *dev)
 	iprintf(ctx, "- node: %s\n", dev->devnode);
 
 	print_evdev_description(ctx, dev);
+	print_hid_report_descriptor(ctx, dev);
 	print_udev_properties(ctx, dev);
 	print_device_quirks(ctx, dev);
 	print_libinput_description(ctx, dev);

tools/libinput-record.man

@@ -145,6 +145,7 @@ devices:
         57: [0, 65535, 0, 0, 0]
         58: [0, 255, 0, 0, 0]
       properties: [0, 2, 4]
+    hid: [12, 23, 34, 45, ...]
     udev:
       properties:
       - ID_INPUT_MOUSE=1
@@ -225,6 +226,9 @@ the device node recorded
 .B evdev
 A dictionary with the evdev device information.
 .TP 8
+.B hid
+A list of integers representing the HID report descriptor bytes.
+.TP 8
 .B udev
 A dictionary with the udev device information.
 .TP 8