[PATCH 5/6] test,funcs: add uresolve() tests

Add test for uresolve() symbol lookup failure with/without fallback.
Also add positive test which does per-target and systemwide context
uresolve() lookups, ensuring expected value is found.

Signed-off-by: Alan Maguire <[email protected]>
Assisted-by: OpenAI Codex (GPT-5) <[email protected]>
---
 test/unittest/funcs/uresolve/err.nofallback.d |  21 +++
 test/unittest/funcs/uresolve/err.nofallback.r |   2 +
 test/unittest/funcs/uresolve/tst.fallback.d   |  25 +++
 test/unittest/funcs/uresolve/tst.fallback.r   |   2 +
 test/unittest/funcs/uresolve/tst.positive.sh  | 144 ++++++++++++++++++
 5 files changed, 194 insertions(+)
 create mode 100644 test/unittest/funcs/uresolve/err.nofallback.d
 create mode 100644 test/unittest/funcs/uresolve/err.nofallback.r
 create mode 100644 test/unittest/funcs/uresolve/tst.fallback.d
 create mode 100644 test/unittest/funcs/uresolve/tst.fallback.r
 create mode 100755 test/unittest/funcs/uresolve/tst.positive.sh

diff --git a/test/unittest/funcs/uresolve/err.nofallback.d b/test/unittest/funcs/uresolve/err.nofallback.d
new file mode 100644
index 00000000..5d6a1e87
--- /dev/null
+++ b/test/unittest/funcs/uresolve/err.nofallback.d
@@ -0,0 +1,21 @@
+/*
+ * Oracle Linux DTrace.
+ * Copyright (c) 2026, 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.
+ */
+
+/* @@trigger: longsleep */
+
+/*
+ * ASSERTION: uresolve() withot fallback for unknown symbol fails.
+ *
+ * SECTION: Functions and Variables/uresolve()
+ */
+
+#pragma D option quiet
+
+BEGIN
+{
+	x = uresolve("a.out`__dtrace_no_such_symbol__");
+}
diff --git a/test/unittest/funcs/uresolve/err.nofallback.r b/test/unittest/funcs/uresolve/err.nofallback.r
new file mode 100644
index 00000000..b93f9f78
--- /dev/null
+++ b/test/unittest/funcs/uresolve/err.nofallback.r
@@ -0,0 +1,2 @@
+-- @@stderr --
+dtrace: failed to compile script test/unittest/funcs/uresolve/err.nofallback.d: line 20: failed to resolve target user symbol a.out`__dtrace_no_such_symbol__
diff --git a/test/unittest/funcs/uresolve/tst.fallback.d b/test/unittest/funcs/uresolve/tst.fallback.d
new file mode 100644
index 00000000..a2d5e203
--- /dev/null
+++ b/test/unittest/funcs/uresolve/tst.fallback.d
@@ -0,0 +1,25 @@
+/*
+ * Oracle Linux DTrace.
+ * Copyright (c) 2026, 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.
+ */
+
+/* @@trigger: longsleep */
+
+/*
+ * ASSERTION: uresolve() returns its optional fallback value when a target
+ * user symbol cannot be resolved.
+ *
+ * SECTION: Functions and Variables/uresolve()
+ */
+
+#pragma D option quiet
+
+BEGIN
+{
+	x = uresolve("a.out`__dtrace_no_such_symbol__", 0);
+	y = uresolve("a.out`__dtrace_no_such_symbol2__", 0xdeadbeef);
+	printf("%lu %lx\n", (unsigned long)x, (unsigned long)y);
+	exit(0);
+}
diff --git a/test/unittest/funcs/uresolve/tst.fallback.r b/test/unittest/funcs/uresolve/tst.fallback.r
new file mode 100644
index 00000000..a224d874
--- /dev/null
+++ b/test/unittest/funcs/uresolve/tst.fallback.r
@@ -0,0 +1,2 @@
+0 deadbeef
+
diff --git a/test/unittest/funcs/uresolve/tst.positive.sh b/test/unittest/funcs/uresolve/tst.positive.sh
new file mode 100755
index 00000000..a552695b
--- /dev/null
+++ b/test/unittest/funcs/uresolve/tst.positive.sh
@@ -0,0 +1,144 @@
+#!/bin/bash
+#
+# Oracle Linux DTrace.
+# Copyright (c) 2026, 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.
+
+# @@timeout: 80
+
+if [ $# != 1 ]; then
+	echo expected one argument: '<'dtrace-path'>'
+	exit 2
+fi
+
+dtrace=$1
+DIRNAME="$tmpdir/uresolve.$$.$RANDOM"
+holdpid=
+firepid=
+
+cleanup()
+{
+	if [ -n "$holdpid" ]; then
+		kill "$holdpid" >/dev/null 2>&1
+		wait "$holdpid" >/dev/null 2>&1
+		holdpid=
+	fi
+	if [ -n "$firepid" ]; then
+		kill "$firepid" >/dev/null 2>&1
+		wait "$firepid" >/dev/null 2>&1
+		firepid=
+	fi
+}
+
+trap cleanup EXIT
+
+fail()
+{
+	echo "ERROR: $1"
+	if [ -f D.out ]; then
+		echo "==== DTrace output"
+		cat D.out
+	fi
+	cleanup
+	exit 1
+}
+
+mkdir -p "$DIRNAME" || exit 1
+cd "$DIRNAME" || exit 1
+
+cat > prov.d <<EOF
+provider uresolve_tst {
+	probe go();
+};
+EOF
+
+cat > main.c <<EOF
+#include <signal.h>
+#include <string.h>
+#include <unistd.h>
+#include "prov.h"
+
+volatile int uresolve_tst_value = 0x12345678;
+
+__attribute__((noinline)) void
+uresolve_tst_fire(void)
+{
+	URESOLVE_TST_GO();
+}
+
+int
+main(int argc, char **argv)
+{
+	int i;
+
+	if (argc > 1 && strcmp(argv[1], "hold") == 0) {
+		for (;;)
+			pause();
+	}
+
+	if (argc > 1 && strcmp(argv[1], "wait") == 0) {
+		for (i = 0; i < 400 && !URESOLVE_TST_GO_ENABLED(); i++)
+			usleep(50000);
+		if (!URESOLVE_TST_GO_ENABLED())
+			return 2;
+		sleep(2);
+	}
+
+	uresolve_tst_fire();
+	return 0;
+}
+EOF
+
+$dtrace $dt_flags -h -s prov.d || fail "failed to generate USDT header"
+$CC $test_cppflags -O0 -fPIE -fno-inline -c main.c ||
+	fail "failed to compile test object"
+$dtrace $dt_flags -G -s prov.d main.o || fail "failed to generate USDT DOF"
+$CC $test_ldflags -fPIE -pie -Wl,--export-dynamic -o main main.o prov.o ||
+	fail "failed to link test program"
+
+$dtrace $dt_flags -q -c ./main -n '
+pid$target:a.out:uresolve_tst_fire:entry
+{
+	this->val = (int *)copyin(uresolve("a.out`uresolve_tst_value"),
+	    sizeof(int));
+	exit(*this->val == 0x12345678 ? 0 : 1);
+}' > D.out 2>&1 || fail "pid target uresolve failed"
+
+$dtrace $dt_flags -q -c "./main wait" -n '
+uresolve_tst$target:::go
+{
+	this->val = (int *)copyin(uresolve("uresolve_tst_value"),
+	    sizeof(int));
+	exit(*this->val == 0x12345678 ? 0 : 1);
+}' > D.out 2>&1 || fail "target USDT uresolve failed"
+
+./main hold &
+holdpid=$!
+sleep 1
+
+$dtrace $dt_flags -Zq -p "$holdpid" -n '
+uresolve_tst*:::go
+/pid != $target/
+{
+	this->val = (int *)copyin(uresolve("a.out`uresolve_tst_value"),
+	    sizeof(int));
+	exit(*this->val == 0x12345678 ? 0 : 1);
+}
+
+tick-1s
+/i++ > 30/
+{
+	exit(1);
+}' > D.out 2>&1 &
+dtpid=$!
+
+sleep 1
+./main wait &
+firepid=$!
+wait "$dtpid" || fail "system-wide USDT uresolve with target failed"
+wait "$firepid" >/dev/null 2>&1
+firepid=
+
+cleanup
+exit 0
-- 
2.43.5