ctdb-common: CID 1507498: Control flow issues (DEADCODE)

Fix typo in error checking.  While here adjust the bottom of the
range, making errno 0 invalid.

Add corresponding test cases using an alternative syntax for errno packets
(#nnn[;] - trailing ';' is optional).

Signed-off-by: Martin Schwenke <martin@meltin.net>
Reviewed-by: Amitay Isaacs <amitay@gmail.com>

Autobuild-User(master): Amitay Isaacs <amitay@samba.org>
Autobuild-Date(master): Mon Aug  1 09:19:55 UTC 2022 on sn-devel-184

3 files changed, 41 insertions, 1 deletions

diff --git a/ctdb/common/tmon.c b/ctdb/common/tmon.c
index 87a55e3b1e9..04bad1f3bf4 100644
--- a/ctdb/common/tmon.c
+++ b/ctdb/common/tmon.c
@@ -97,7 +97,7 @@ bool tmon_set_exit(struct tmon_pkt *pkt)
 
 bool tmon_set_errno(struct tmon_pkt *pkt, int err)
 {
-	if (err < 0 && err > UINT16_MAX) {
+	if (err <= 0 || err > UINT16_MAX) {
 		return false;
 	}
 
diff --git a/ctdb/tests/UNIT/cunit/tmon_test_002.sh b/ctdb/tests/UNIT/cunit/tmon_test_002.sh
index 97a17a188e5..e4118a3d09a 100755
--- a/ctdb/tests/UNIT/cunit/tmon_test_002.sh
+++ b/ctdb/tests/UNIT/cunit/tmon_test_002.sh
@@ -4,6 +4,7 @@
 
 epipe=$(errcode EPIPE)
 etimedout=$(errcode ETIMEDOUT)
+edom=$(errcode EDOM)
 
 test_cases()
 {
@@ -35,6 +36,34 @@ WRITER OK
 EOF
 	unit_test tmon_test "7" false 0 false
 
+	test_case "errno 110 packet @ 1s, no timeout"
+	ok <<EOF
+READER ERR=110
+WRITER OK
+EOF
+	unit_test tmon_test "#110" false 0 false
+
+	test_case "errno 0 error causes EDOM @ 1s, no timeout"
+	ok <<EOF
+WRITER ERR=$edom
+READER ERR=$epipe
+EOF
+	unit_test tmon_test "#0;" false 0 false
+
+	test_case "errno -1 error causes EDOM @ 1s, no timeout"
+	ok <<EOF
+WRITER ERR=$edom
+READER ERR=$epipe
+EOF
+	unit_test tmon_test "#-1;" false 0 false
+
+	test_case "errno 70000 error causes EDOM @ 1s, no timeout"
+	ok <<EOF
+WRITER ERR=$edom
+READER ERR=$epipe
+EOF
+	unit_test tmon_test "#70000;!0" false 0 false
+
 	test_case "Exit packet @ 3s, no timeout"
 	ok <<EOF
 READER OK
diff --git a/ctdb/tests/src/tmon_test.c b/ctdb/tests/src/tmon_test.c
index 651c24b7414..fb1f5eb9d30 100644
--- a/ctdb/tests/src/tmon_test.c
+++ b/ctdb/tests/src/tmon_test.c
@@ -45,6 +45,7 @@ static int test_write_callback(void *private_data, struct tmon_pkt *pkt)
 		private_data, struct test_write_state);
 	bool status;
 	size_t len;
+	char *end;
 	int err;
 	char c;
 	const char *t;
@@ -75,6 +76,16 @@ static int test_write_callback(void *private_data, struct tmon_pkt *pkt)
 		case '!':
 			status = tmon_set_ping(pkt);
 			break;
+		case '#':
+			/* Additional errno syntax: #nnn[;] */
+			t = &state->write_data[state->offset];
+			err = (int)strtol(t, &end, 10);
+			state->offset += (end - t);
+			if (state->write_data[state->offset] == ';') {
+				state->offset++;
+			}
+			status = tmon_set_errno(pkt, err);
+			break;
 		default:
 			status = false;
 		}