From 0e39201fbb77cde4427688e51e1d44db56a6b412 Mon Sep 17 00:00:00 2001
From: Ihor Solodrai <ihor.solodrai@pm.me>
Date: Thu, 23 Jan 2025 14:20:57 -0800
Subject: [PATCH] tests: avoid sending signals in run_test.sh

Change run_test.sh and .bt script such that bpftrace terminates at the
end of target test program. Compare the test output after bpftrace has
terminated.

Using kill -INT to stop bpftrace may interfere with CI environment,
because this signal may be interpreted as a job failure.

I tried bpftrace -c [1] to work around this, however it turned out to
not work for these tests when there are tracepoints refering to
dynamic libraries. This is because the .so is not loaded yet when
bpftrace attempts to attach to the child process.

[1] https://docs.bpftrace.org/latest#-c-command

Signed-off-by: Ihor Solodrai <ihor.solodrai@pm.me>
---
 tests/prepare-bt-script.awk |  4 ++-
 tests/run_test.sh           | 58 +++++++++++++++++++++----------------
 2 files changed, 36 insertions(+), 26 deletions(-)

diff --git a/tests/prepare-bt-script.awk b/tests/prepare-bt-script.awk
index 55eaeb3..254187f 100644
--- a/tests/prepare-bt-script.awk
+++ b/tests/prepare-bt-script.awk
@@ -46,6 +46,8 @@
 }
 
 END {
-	if (has_contents)
+	if (has_contents) {
+		printf("uretprobe:%s:main { exit(); }\n", OUTPUT "/" TEST);
 		printf("END { printf(\"DONE!\\n\"); }\n");
+	}
 }
diff --git a/tests/run_test.sh b/tests/run_test.sh
index ea4389a..90c90e5 100755
--- a/tests/run_test.sh
+++ b/tests/run_test.sh
@@ -69,36 +69,44 @@ if [ -s "$TEST_BTSCRIPT" ]; then
 	bt_pid=$!
 	bt_pgid="$(ps -opgid= "$bt_pid" | tr -d ' ')"
 
+	dump_bt_output() {
+		echo "BPFTRACE SCRIPT:"
+		cat "$TEST_BTSCRIPT"
+		echo "BPFTRACE OUTPUT:"
+		cat "$TEST_BTOUT_RAW"
+	}
+
+	wait_for_bpftrace() {
+		local bt_start=$(date +%s)
+		local stop_word="$1"
+		local msg="$2"
+		while true; do
+			local bt_elapsed=$(( $(date +%s) - bt_start ))
+			if grep -q "$stop_word" "$TEST_BTOUT_RAW"; then
+				break
+			elif [ "$bt_elapsed" -ge "$TIMEOUT" ]; then
+				sudo kill -KILL -$bt_pgid 2>/dev/null
+				echo "BPFTRACE ${msg} TIMEOUT!"
+				dump_bt_output
+				exit 1
+			elif ! kill -s 0 "$bt_pid"; then
+				echo "BPFTRACE ${msg} FAILURE!"
+				dump_bt_output
+				exit 1
+			else
+				sleep 0.2
+			fi
+		done
+	}
+
 	# wait for bpftrace to finish attachment
-	bt_start=$(date +%s)
-	while true; do
-		bt_elapsed=$(( $(date +%s) - bt_start ))
-		if grep -q "STARTED!" "$TEST_BTOUT_RAW"; then
-			break
-		elif [ "$bt_elapsed" -ge "$TIMEOUT" ]; then
-			sudo kill -KILL -$bt_pgid 2>/dev/null
-			echo "BPFTRACE STARTUP TIMEOUT!"
-			echo "BPFTRACE SCRIPT:"
-			cat "$TEST_BTSCRIPT"
-			echo "BPFTRACE OUTPUT:"
-			cat "$TEST_BTOUT_RAW"
-			exit 1
-		elif ! kill -s 0 "$bt_pid"; then
-			echo "BPFTRACE STARTUP FAILURE!"
-			echo "BPFTRACE SCRIPT:"
-			cat "$TEST_BTSCRIPT"
-			echo "BPFTRACE OUTPUT:"
-			cat "$TEST_BTOUT_RAW"
-			exit 1
-		else
-			sleep 0.2
-		fi
-	done
+	wait_for_bpftrace "STARTED!" "STARTUP"
 
 	# get test output while bpftrace is attached
 	$TEST_BIN &>"$TEST_OUT"
 
-	sudo kill -INT -$bt_pgid 2>/dev/null
+	# wait for bpftrace to terminate
+	wait_for_bpftrace "DONE!" "RUNNING"
 
 	$awk '/STARTED!/ {flag=1; next} /DONE!/ {flag=0} flag' $TEST_BTOUT_RAW > $TEST_BTOUT
 	if ! $awk -f check-match.awk $TEST_BTOUT_SPEC $TEST_BTOUT; then