[DTrace-devel] [PATCH] test: Check tid value

[eugene.loh at oracle.com]

From: Eugene Loh <eugene.loh at oracle.com>

We were checking the built-in variable tid simply by testing
that we could print it and its value was not -1.

Add a test that confirms the value is actually correct;
compare to C output of gettid().

In line with other similar tests, also check for the profile
provider.

While we're at it, check the pid value and the pthread_t value
returned via pthread_create().

Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
---
 test/unittest/builtinvar/tst.tid_pid.r  |   1 +
 test/unittest/builtinvar/tst.tid_pid.sh | 126 ++++++++++++++++++++++++
 2 files changed, 127 insertions(+)
 create mode 100644 test/unittest/builtinvar/tst.tid_pid.r
 create mode 100755 test/unittest/builtinvar/tst.tid_pid.sh

diff --git a/test/unittest/builtinvar/tst.tid_pid.r b/test/unittest/builtinvar/tst.tid_pid.r
new file mode 100644
index 000000000..2e9ba477f
--- /dev/null
+++ b/test/unittest/builtinvar/tst.tid_pid.r
@@ -0,0 +1 @@
+success
diff --git a/test/unittest/builtinvar/tst.tid_pid.sh b/test/unittest/builtinvar/tst.tid_pid.sh
new file mode 100755
index 000000000..7ff0227fe
--- /dev/null
+++ b/test/unittest/builtinvar/tst.tid_pid.sh
@@ -0,0 +1,126 @@
+#!/bin/bash
+#
+# Oracle Linux DTrace.
+# Copyright (c) 2025, 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.
+#
+
+dtrace=$1
+CC=/usr/bin/gcc
+
+DIRNAME="$tmpdir/builtinvar-tid_pid.$$.$RANDOM"
+mkdir -p $DIRNAME
+cd $DIRNAME
+
+# Create trigger program.
+
+cat << EOF > main.c
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/syscall.h>
+#include <pthread.h>
+
+/* Provide an implementation in case glibc is too old. */
+pid_t gettid(void)
+{
+        return syscall(__NR_gettid);
+}
+
+static void * foo(void *arg) {
+	int i = 0;
+
+	/*
+	 * Each thread reports the pid and tid values it expects.
+	 * (Expect the same values for both the pid and profile probes.)
+	 */
+	printf("pid     probe expect pid %d tid %d\n", getpid(), gettid());
+	printf("profile probe expect pid %d tid %d\n", getpid(), gettid());
+	fflush(stdout);
+
+	/* Wait endlessly.  DTrace will kill me when it is done. */
+	while (i < 2)
+		i ^= 1;
+
+	return 0;
+}
+
+int main(int c, char **v) {
+	pthread_t mythr;
+
+	/* Create a thread. */
+	pthread_create(&mythr, NULL, &foo, NULL);
+
+	/* Also report the pthread_t. */
+	printf("created pthread_t %lld\n\n", mythr);
+	fflush(stdout);
+
+	/* Wait endlessly.  DTrace will kill me when it is done. */
+	pthread_join(mythr, NULL);
+
+	return 0;
+}
+EOF
+
+# Compile the trigger program.
+
+$CC $test_cppflags main.c -lpthread
+if [ $? -ne 0 ]; then
+    echo compilation failed
+    exit 1
+fi
+
+# Run DTrace.
+
+rm -f C.out D.out
+$dtrace $dt_flags -o D.out -c ./a.out -qn '
+/* Report pid and tid from a pid-provider probe. */
+pid$target:a.out:foo:entry
+{
+	self->mypid = pid;
+	printf("pid     probe expect pid %d tid %d\n", pid, tid);
+}
+
+/* Report pid and tid from a profile-provider probe.  Look for the thread we created. */
+profile:::profile-1s
+/self->mypid != 0/
+{
+	printf("profile probe expect pid %d tid %d\n", pid, tid);
+	exit(0);
+}
+
+/* While we are at it, check the pthread_t returned via pthread_create(). */
+pid$target::pthread_create:entry
+{
+	self->thrid_p = (uintptr_t) arg0;
+}
+pid$target::pthread_create:return
+{
+	printf("created pthread_t %lld\n", *((long long *)copyin(self->thrid_p, sizeof(long long *))));
+	self->thrid_p = 0
+}' |& sort > C.out
+if [ $? -ne 0 ]; then
+	echo DTrace failed
+	echo ==== C.out
+	cat C.out
+	echo ==== D.out
+	cat D.out
+	exit 1
+fi
+
+# Compare the C and D output.
+
+sort D.out > D.out.sorted
+if ! diff -q C.out D.out.sorted ; then
+	echo ERROR: mismatch
+	echo ==== C.out
+	cat C.out
+	echo ==== D.out
+	cat D.out.sorted
+	echo ==== diff
+	diff C.out D.out.sorted
+	exit 1
+fi
+
+echo success
+exit 0
-- 
2.43.5