Merge pull request #108113 from cockroachdb/blathers/backport-release…

…-23.1-108094

pkg/BUILD.bazel

@@ -671,6 +671,7 @@ ALL_TESTS = [
     "//pkg/util/timeofday:timeofday_test",
     "//pkg/util/timetz:timetz_test",
     "//pkg/util/timeutil/pgdate:pgdate_test",
+    "//pkg/util/timeutil/ptp:ptp_test",
     "//pkg/util/timeutil:timeutil_test",
     "//pkg/util/tochar:tochar_test",
     "//pkg/util/tracing/collector:collector_test",
@@ -2320,6 +2321,7 @@ GO_TARGETS = [
     "//pkg/util/timeutil/pgdate:pgdate",
     "//pkg/util/timeutil/pgdate:pgdate_test",
     "//pkg/util/timeutil/ptp:ptp",
+    "//pkg/util/timeutil/ptp:ptp_test",
     "//pkg/util/timeutil:timeutil",
     "//pkg/util/timeutil:timeutil_test",
     "//pkg/util/tochar:tochar",

pkg/util/timeutil/ptp/BUILD.bazel

@@ -1,4 +1,4 @@
-load("@io_bazel_rules_go//go:def.bzl", "go_library")
+load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
 
 go_library(
     name = "ptp",
@@ -59,3 +59,19 @@ go_library(
         "//conditions:default": [],
     }),
 )
+
+go_test(
+    name = "ptp_test",
+    srcs = ["ptp_clock_linux_test.go"],
+    args = ["-test.timeout=295s"],
+    embed = [":ptp"],
+    deps = select({
+        "@io_bazel_rules_go//go/platform:android": [
+            "//pkg/util/timeutil",
+        ],
+        "@io_bazel_rules_go//go/platform:linux": [
+            "//pkg/util/timeutil",
+        ],
+        "//conditions:default": [],
+    }),
+)

pkg/util/timeutil/ptp/ptp_clock_linux.go

@@ -79,5 +79,10 @@ func (p Clock) Now() time.Time {
 		panic(err)
 	}
 
-	return timeutil.Unix(int64(ts.tv_sec)*1e9, int64(ts.tv_nsec))
+	return timeutil.Unix(int64(ts.tv_sec), int64(ts.tv_nsec))
+}
+
+// realtime returns a clock using the system CLOCK_REALTIME device. For testing.
+func realtime() Clock {
+	return Clock{clockDeviceID: uintptr(C.CLOCK_REALTIME)}
 }

pkg/util/timeutil/ptp/ptp_clock_linux_test.go

@@ -0,0 +1,30 @@
+// Copyright 2023 The Cockroach Authors.
+//
+// Use of this software is governed by the Business Source License
+// included in the file licenses/BSL.txt.
+//
+// As of the Change Date specified in that file, in accordance with
+// the Business Source License, use of this software will be governed
+// by the Apache License, Version 2.0, included in the file
+// licenses/APL.txt.
+
+//go:build linux
+// +build linux
+
+package ptp
+
+import (
+	"testing"
+	"time"
+
+	"github.com/cockroachdb/cockroach/pkg/util/timeutil"
+)
+
+// TestClockNow sanity checks that Clock.Now() sourced from the CLOCK_REALTIME
+// device returns time close to timeutil.Now(). This ensures that the conversion
+// from the time returned by a clock device to Go's time.Time is correct.
+func TestClockNow(t *testing.T) {
+	if got, want := realtime().Now(), timeutil.Now(); want.Sub(got).Abs() > 10*time.Second {
+		t.Errorf("clock mismatch: got %v; timeutil says %v", got, want)
+	}
+}