udev: parse the EVDEV_ABS properties for a potential fuzz setting

Where a fuzz is defined in the 60-evdev.hwdb, we rely on a udev builtin to
set the kernel device to that fuzz value. Unfortunately that happens after our
program is called with this order of events:
1. 60-evdev.rules calls IMPORT(builtin) for the hwdb which sets the EVDEV_ABS_*
  properties. It also sets RUN{builtin}=keyboard but that's not invoked yet.
2. 90-libinput-fuzz-override.rules calls IMPORT{program} for our fuzz override
  bits. That sets the kernel fuzz value to 0 and sets the LIBINPUT_FUZZ_*
  propertie
3. The keyboard builtin is run once all the rules have been processed.

Our problem is that where the fuzz is set in a hwdb entry, the kernel fuzz is
still unset when we get to look at it, so we always end up with a fuzz of zero
for us and a nonzero kernel fuzz.

Work around this by checking the EVDEV_ABS property, extracting the fuzz from
there and re-printing that property without the fuzz. This way we ensure the
kernel remains at zero fuzz and we use the one from the hwdb instead.

Fixes #346

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

1 files changed, 78 insertions, 0 deletions

diff --git a/test/test-utils.c b/test/test-utils.c
index 46355a59..27091a01 100644
--- a/test/test-utils.c
+++ b/test/test-utils.c
@@ -546,6 +546,83 @@ START_TEST(evcode_prop_parser)
 }
 END_TEST
 
+START_TEST(evdev_abs_parser)
+{
+	struct test {
+		uint32_t which;
+		const char *prop;
+		int min, max, res, fuzz, flat;
+
+	} tests[] = {
+		{ .which = (ABS_MASK_MIN|ABS_MASK_MAX),
+		  .prop = "1:2",
+		  .min = 1, .max = 2 },
+		{ .which = (ABS_MASK_MIN|ABS_MASK_MAX),
+		  .prop = "1:2:",
+		  .min = 1, .max = 2 },
+		{ .which = (ABS_MASK_MIN|ABS_MASK_MAX|ABS_MASK_RES),
+		  .prop = "10:20:30",
+		  .min = 10, .max = 20, .res = 30 },
+		{ .which = (ABS_MASK_RES),
+		  .prop = "::100",
+		  .res = 100 },
+		{ .which = (ABS_MASK_MIN),
+		  .prop = "10:",
+		  .min = 10 },
+		{ .which = (ABS_MASK_MAX|ABS_MASK_RES),
+		  .prop = ":10:1001",
+		  .max = 10, .res = 1001 },
+		{ .which = (ABS_MASK_MIN|ABS_MASK_MAX|ABS_MASK_RES|ABS_MASK_FUZZ),
+		  .prop = "1:2:3:4",
+		  .min = 1, .max = 2, .res = 3, .fuzz = 4},
+		{ .which = (ABS_MASK_MIN|ABS_MASK_MAX|ABS_MASK_RES|ABS_MASK_FUZZ|ABS_MASK_FLAT),
+		  .prop = "1:2:3:4:5",
+		  .min = 1, .max = 2, .res = 3, .fuzz = 4, .flat = 5},
+		{ .which = (ABS_MASK_MIN|ABS_MASK_RES|ABS_MASK_FUZZ|ABS_MASK_FLAT),
+		  .prop = "1::3:4:50",
+		  .min = 1, .res = 3, .fuzz = 4, .flat = 50},
+		{ .which = ABS_MASK_FUZZ|ABS_MASK_FLAT,
+		  .prop = ":::5:60",
+		  .fuzz = 5, .flat = 60},
+		{ .which = ABS_MASK_FUZZ,
+		  .prop = ":::5:",
+		  .fuzz = 5 },
+		{ .which = ABS_MASK_RES, .prop = "::12::",
+		  .res = 12 },
+		/* Malformed property but parsing this one makes us more
+		 * future proof */
+		{ .which = (ABS_MASK_RES|ABS_MASK_FUZZ|ABS_MASK_FLAT),
+		  .prop = "::12:1:2:3:4:5:6",
+		  .res = 12, .fuzz = 1, .flat = 2 },
+		{ .which = 0, .prop = ":::::" },
+		{ .which = 0, .prop = ":" },
+		{ .which = 0, .prop = "" },
+		{ .which = 0, .prop = ":asb::::" },
+		{ .which = 0, .prop = "foo" },
+	};
+	struct test *t;
+
+	ARRAY_FOR_EACH(tests, t) {
+		struct input_absinfo abs;
+		uint32_t mask;
+
+		mask = parse_evdev_abs_prop(t->prop, &abs);
+		ck_assert_int_eq(mask, t->which);
+
+		if (t->which & ABS_MASK_MIN)
+			ck_assert_int_eq(abs.minimum, t->min);
+		if (t->which & ABS_MASK_MAX)
+			ck_assert_int_eq(abs.maximum, t->max);
+		if (t->which & ABS_MASK_RES)
+			ck_assert_int_eq(abs.resolution, t->res);
+		if (t->which & ABS_MASK_FUZZ)
+			ck_assert_int_eq(abs.fuzz, t->fuzz);
+		if (t->which & ABS_MASK_FLAT)
+			ck_assert_int_eq(abs.flat, t->flat);
+	}
+}
+END_TEST
+
 START_TEST(time_conversion)
 {
 	ck_assert_int_eq(us(10), 10);
@@ -1050,6 +1127,7 @@ litest_utils_suite(void)
 	tcase_add_test(tc, calibration_prop_parser);
 	tcase_add_test(tc, range_prop_parser);
 	tcase_add_test(tc, evcode_prop_parser);
+	tcase_add_test(tc, evdev_abs_parser);
 	tcase_add_test(tc, safe_atoi_test);
 	tcase_add_test(tc, safe_atoi_base_16_test);
 	tcase_add_test(tc, safe_atoi_base_8_test);