Move Linux client & common packages into a public repo.

wgengine/rusage_nowindows.go

@@ -0,0 +1,29 @@
+// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !windows
+
+package wgengine
+
+import (
+	"runtime"
+	"syscall"
+)
+
+func rusageMaxRSS() float64 {
+	var ru syscall.Rusage
+	err := syscall.Getrusage(syscall.RUSAGE_SELF, &ru)
+	if err != nil {
+		return 0
+	}
+
+	rss := float64(ru.Maxrss)
+	if runtime.GOOS == "darwin" {
+		rss /= 1 << 20 // ru_maxrss is bytes on darwin
+	} else {
+		// ru_maxrss is kilobytes elsewhere (linux, openbsd, etc)
+		rss /= 1024
+	}
+	return rss
+}