tests: Improve port-checking infrastructure.tmp-work-without-netstat

The test suite unnecessarily failed on systems without netstat because
it was assumed to be present.  Instead of simply checking for its
presence and indicating an unsupported test, however, the ss utility
can be used as a drop-in replacement.  When netstat/net-tools is not
present, the ss utility from iproute2 still stands a fair chance of
existing, and they also have similar enough semantics that they can be
used interchangeably in the test suite.

The functions in tests/scripts/common.sh that used netstat
(wait_for_port, wait_for_free_port) now use new functions,
check_if_port_in_use and check_if_port_listening, to abstract the call
to netstat/ss.  The eval'd variable GETPORT also used netstat, and has
been updated accordingly.

The new port-checking functions use another new function,
have_port_finder, which takes care of the details of selecting ss
(preferred) or netstat, or fails otherwise.

Signed-off-by: Rical Jasan <ricaljasan@pacific.net>
Signed-off-by: Nikos Mavrogiannopoulos <nmav@redhat.com>

1 files changed, 47 insertions, 6 deletions

diff --git a/tests/scripts/common.sh b/tests/scripts/common.sh
index 3cf841c25b..518d8416bc 100644
--- a/tests/scripts/common.sh
+++ b/tests/scripts/common.sh
@@ -21,9 +21,50 @@
 
 export TZ="UTC"
 
-GETPORT='rc=0;myrandom=$(date +%N | sed 's/^0*//');while test $rc = 0;do PORT="$(((($$<<15)|$myrandom) % 63001 + 2000))";
-	netstat -anl|grep "[\:\.]$PORT" >/dev/null 2>&1;
-	rc=$?;done;'
+# Check for a utility to list ports.  Both ss and netstat will list
+# ports for normal users, and have similar semantics, so put the
+# command in the caller's PFCMD, or exit, indicating an unsupported
+# test.  Prefer ss from iproute2 over the older netstat.
+have_port_finder() {
+	for file in $(which ss) /*bin/ss /usr/*bin/ss /usr/local/*bin/ss;do
+		if test -x "$file";then
+			PFCMD="$file";return 0
+		fi
+	done
+
+	if test -z "$PFCMD";then
+	for file in $(which netstat) /bin/netstat /usr/bin/netstat /usr/local/bin/netstat;do
+		if test -x "$file";then
+			PFCMD="$file";return 0
+		fi
+	done
+	fi
+
+	if test -z "$PFCMD";then
+		echo "neither ss nor netstat found"
+		exit 1
+	fi
+}
+
+check_if_port_in_use() {
+	local PORT="$1"
+	local PFCMD; have_port_finder
+	$PFCMD -an|grep "[\:\.]$PORT" >/dev/null 2>&1
+}
+
+check_if_port_listening() {
+	local PORT="$1"
+	local PFCMD; have_port_finder
+	$PFCMD -anl|grep "[\:\.]$PORT"|grep LISTEN >/dev/null 2>&1
+}
+
+# Find a port number not currently in use.
+GETPORT='rc=0; myrandom=$(date +%N | sed s/^0*//)
+    while test $rc = 0;do
+	PORT="$(((($$<<15)|$myrandom) % 63001 + 2000))"
+	check_if_port_in_use $PORT;rc=$?
+    done
+'
 
 check_for_datefudge() {
 	TSTAMP=`datefudge -s "2006-09-23" date -u +%s || true`
@@ -49,10 +90,10 @@ wait_for_port()
 	sleep 4
 
 	for i in 1 2 3 4 5 6;do
-		netstat -anl|grep "[\:\.]$PORT"|grep LISTEN >/dev/null 2>&1
+		check_if_port_listening ${PORT}
 		ret=$?
 		if test $ret != 0;then
-		netstat -anl|grep "[\:\.]$PORT"
+		check_if_port_in_use ${PORT}
 			echo try $i
 			sleep 2
 		else
@@ -68,7 +109,7 @@ wait_for_free_port()
 	local PORT="$1"
 
 	for i in 1 2 3 4 5 6;do
-		netstat -anl|grep "[\:\.]$PORT" >/dev/null 2>&1
+		check_if_port_in_use ${PORT}
 		ret=$?
 		if test $ret != 0;then
 			break