test, usdt: test multiple simultaneous tracers of multiple processes

We start them one after the other, to determine whether starting (or
starting tracing) one process affects the same active tracepoints in
other processes currently being traced.

Signed-off-by: Nick Alcock <nick.alcock@oracle.com>
Reviewed-by: Kris Van Hees <kris.van.hees@oracle.com>

test/unittest/usdt/tst.multitrace.sh

@@ -0,0 +1,142 @@
+#!/bin/bash
+#
+# Oracle Linux DTrace.
+# Copyright (c) 2006, 2023, Oracle and/or its affiliates. All rights reserved.
+# Licensed under the Universal Permissive License v 1.0 as shown at
+# http://oss.oracle.com/licenses/upl.
+#
+# Test multiple simultaneous tracers, invoked successively (so there
+# are multiple dtracers and multiple processes tracing the same probes).
+#
+# @@xfail: something up with multiple simultaneous exiting tracers
+if [ $# != 1 ]; then
+	echo expected one argument: '<'dtrace-path'>'
+	exit 2
+fi
+
+dtrace=$1
+CC=/usr/bin/gcc
+CFLAGS=
+
+DIRNAME="$tmpdir/usdt-multitrace.$$.$RANDOM"
+mkdir -p $DIRNAME
+cd $DIRNAME
+
+cat > multitrace.d <<EOF
+provider test_multitrace {
+	probe go();
+	probe exiting();
+};
+EOF
+
+$dtrace -h -s multitrace.d
+if [ $? -ne 0 ]; then
+	echo "failed to generate header file" >& 2
+	exit 1
+fi
+
+cat > test.c <<EOF
+#include <sys/types.h>
+#include "multitrace.h"
+
+int
+main(int argc, char **argv)
+{
+	size_t i;
+
+	sleep(5);
+	for (i = 0; i < 5; i++) {
+		if (TEST_MULTITRACE_GO_ENABLED())
+			TEST_MULTITRACE_GO();
+		sleep(1);
+	}
+	TEST_MULTITRACE_EXITING();
+
+	return 0;
+}
+EOF
+
+${CC} ${CFLAGS} -c test.c
+if [ $? -ne 0 ]; then
+	echo "failed to compile test.c" >& 2
+	exit 1
+fi
+$dtrace -G -s multitrace.d test.o
+if [ $? -ne 0 ]; then
+	echo "failed to create DOF" >& 2
+	exit 1
+fi
+${CC} ${CFLAGS} -o test test.o multitrace.o
+if [ $? -ne 0 ]; then
+	echo "failed to link final executable" >& 2
+	exit 1
+fi
+
+script() {
+	$dtrace -qws /dev/stdin $1 $2 $3 <<'EOF'
+	int fired[pid_t];
+	int exited[pid_t];
+
+	test_multitrace$1:::go, test_multitrace$2:::go
+	{
+		printf("tracer %i, process %i fired: %s:%s:%s\n", $3,
+		       curpsinfo->pr_pid, probemod, probefunc, probename);
+	}
+
+	test_multitrace$1:::go, test_multitrace$2:::go
+	/ curpsinfo->pr_pid == $1 || curpsinfo->pr_pid == $2 /
+	{
+		fired[curpsinfo->pr_pid]++;
+	}
+	test_multitrace$1:::exiting, test_multitrace$2:::exiting
+	/ exited[curpsinfo->pr_pid] != 0 /
+	{
+		printf("tracer %i: repeated fires of exit probe of %i observed.\n",
+		       $3, curpsinfo->pr_pid);
+		exit(1);
+	}
+	test_multitrace$1:::exiting, test_multitrace$2:::exiting
+	{
+		printf("tracer %i, process %i, %i fires seen.\n", $3,
+		       curpsinfo->pr_pid, fired[curpsinfo->pr_pid]);
+		exited[curpsinfo->pr_pid] = 1;
+	}
+	test_multitrace$1:::exiting, test_multitrace$2:::exiting
+	/ exited[$1] == 1 && exited[$2] == 1 && fired[$1] == 5 && fired[$2] == 5 /
+	{
+		printf("tracer %i: exiting\n", $3);
+		exit(0);
+	}
+	test_multitrace$1:::exiting, test_multitrace$2:::exiting
+	/ exited[$1] == 1 && exited[$2] == 1 /
+	{
+		printf("tracer %i, %i fires seen from process %i, %i from process %i\n",
+		       $3, fired[$1], $1, fired[$2], $2);
+		exit(1);
+	}
+EOF
+	echo tracer $3: exited
+}
+
+./test 1 &
+ONE=$!
+./test 2 0 &
+TWO=$!
+
+script $ONE $TWO 1 &
+DONE=$!
+
+script $ONE $TWO 2 &
+DTWO=$!
+
+if ! wait $DONE; then
+    exit 1
+fi
+
+if ! wait $DTWO; then
+    exit 1
+fi
+
+wait $ONE $TWO
+
+exit 0