Change GetBootTime to work specificaly with FreeBSD

Signed-off-by: Ricardo Pchevuzinske Katz <ricardo.katz@gmail.com>

pkg/kubelet/util/BUILD

@@ -9,7 +9,8 @@ load(
 go_test(
     name = "go_default_test",
     srcs = [
-        "bootime_util_linux_test.go",
+        "boottime_util_freebsd_test.go",
+        "boottime_util_linux_test.go",
         "util_test.go",
         "util_unix_test.go",
         "util_windows_test.go",
@@ -45,6 +46,7 @@ go_library(
     name = "go_default_library",
     srcs = [
         "boottime_util_darwin.go",
+        "boottime_util_freebsd.go",
         "boottime_util_linux.go",
         "doc.go",
         "nodelease.go",

pkg/kubelet/util/boottime_util_freebsd.go

@@ -0,0 +1,39 @@
+// +build freebsd
+
+/*
+Copyright 2020 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package util
+
+import (
+	"fmt"
+	"time"
+
+	"golang.org/x/sys/unix"
+	"unsafe"
+)
+
+// GetBootTime returns the time at which the machine was started, truncated to the nearest second
+func GetBootTime() (time.Time, error) {
+	currentTime := time.Now()
+	ts := &unix.Timeval{}
+	_, _, e1 := unix.Syscall(uintptr(unix.SYS_CLOCK_GETTIME), uintptr(unix.CLOCK_UPTIME), uintptr(unsafe.Pointer(ts)), 0)
+	if e1 != 0 {
+		return time.Time{}, fmt.Errorf("error getting system uptime")
+	}
+
+	return currentTime.Add(-time.Duration(ts.Sec) * time.Second).Truncate(time.Second), nil
+}

pkg/kubelet/util/boottime_util_freebsd_test.go

@@ -0,0 +1,36 @@
+// +build freebsd
+
+/*
+Copyright 2020 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package util
+
+import (
+	"testing"
+	"time"
+)
+
+func TestGetBootTime(t *testing.T) {
+	boottime, err := GetBootTime()
+
+	if err != nil {
+		t.Errorf("Unable to get system uptime")
+	}
+
+	if !boottime.After(time.Time{}) {
+		t.Errorf("Invalid system uptime")
+	}
+}

pkg/kubelet/util/boottime_util_linux.go

@@ -1,4 +1,4 @@
-// +build freebsd linux
+// +build linux
 
 /*
 Copyright 2018 The Kubernetes Authors.

pkg/kubelet/util/boottime_util_linux_test.go

@@ -1,4 +1,4 @@
-// +build freebsd linux
+// +build linux
 
 /*
 Copyright 2018 The Kubernetes Authors.