[PATCH] selftests: rtc: Support harness test filtering and arguments

[Wake Liu <wakel@google.com>]

rtctest implements its own main() function with a rigid switch (argc)
check that only accepts an optional single argument for the RTC device
node path. This prevents kselftest_harness standard arguments from
working properly:

1. Passing filter options like -t <name> or -T <name> triggers a usage
   error because argc is greater than 2.
2. Passing -l or -h causes rtctest to treat "-l" or "-h" as the device
   node path and fail with access() errors before ever reaching the
   harness argument checker.

Parse command line arguments with getopt() to pass all kselftest harness
options (such as -t, -T, -v, -V, -f, -F, -r, -d, -h, and -l) through to
test_harness_run(), while preserving the ability to specify an optional
RTC device node path as a non-option argument. Also ensure optind is
reset before invoking test_harness_run() so the harness can inspect the
options, and bypass device accessibility checks when help or test
listing is requested.

Signed-off-by: Wake Liu <wakel@google.com>
---
 tools/testing/selftests/rtc/rtctest.c | 44 +++++++++++++++++++++------
 1 file changed, 35 insertions(+), 9 deletions(-)

diff --git a/tools/testing/selftests/rtc/rtctest.c b/tools/testing/selftests/rtc/rtctest.c
index 8047d9879039..57dda87ba813 100644
--- a/tools/testing/selftests/rtc/rtctest.c
+++ b/tools/testing/selftests/rtc/rtctest.c
@@ -486,18 +486,44 @@ TEST_F_TIMEOUT(rtc, alarm_wkalm_set_minute, 65) {
 int main(int argc, char **argv)
 {
 	int ret = -1;
+	int opt, i;
+	int non_opt = 0;
+
+	while ((opt = getopt(argc, argv, "dhlF:f:V:v:t:T:r:")) != -1) {
+		switch (opt) {
+		case 'h':
+			fprintf(stderr,
+				"Usage: %s [-h|-l|-d] [-t|-T|-v|-V|-f|-F|-r name] [rtcdev]\n\n",
+				argv[0]);
+			optind = 1;
+			return test_harness_run(argc, argv);
+		case 'l':
+			optind = 1;
+			return test_harness_run(argc, argv);
+		case '?':
+			fprintf(stderr,
+				"Usage: %s [-h|-l|-d] [-t|-T|-v|-V|-f|-F|-r name] [rtcdev]\n",
+				argv[0]);
+			return KSFT_FAIL;
+		default:
+			break;
+		}
+	}
 
-	switch (argc) {
-	case 2:
-		rtc_file = argv[1];
-		/* FALLTHROUGH */
-	case 1:
-		break;
-	default:
-		fprintf(stderr, "usage: %s [rtcdev]\n", argv[0]);
-		return 1;
+	for (i = optind; i < argc; i++) {
+		if (non_opt == 0) {
+			rtc_file = argv[i];
+			non_opt++;
+		} else {
+			fprintf(stderr,
+				"Usage: %s [-h|-l|-d] [-t|-T|-v|-V|-f|-F|-r name] [rtcdev]\n",
+				argv[0]);
+			return KSFT_FAIL;
+		}
 	}
 
+	optind = 1;
+
 	/* Run the test if rtc_file is accessible */
 	if (access(rtc_file, R_OK) == 0)
 		ret = test_harness_run(argc, argv);
-- 
2.55.0.979.g7e5102b832-goog