cmd/buildlet: always halt Mac VMs after builds, regardless of macOS v…

…ersion

We used to do this only by necessity on Sierra, due to Sierra issues,
but now that x/build/cmd/makemac is better, we can just do this all
the time. Doing it always is better anyway, to guarantee fresh
environments per build.

Also add the forgotten sudo in the Mac halt. The
env/darwin/macstadium/image-setup-notes.txt even calls out how to
setup password-free sudo to the images, but then I forgot to use it.
It only worked before (if it did?) because the process ended and
failed its heartbeat, at least some of the time. It's also possible it
was never working. The old reason that Sierra machines were
special-cased to reboot was reportedly fixed anyway, in
golang/go#18751 (comment).

Updates golang/go#9495

Change-Id: Iea21d7bc07467429cde79f4212c2b91458f8d8d8
Reviewed-on: https://go-review.googlesource.com/82355
Reviewed-by: Brad Fitzpatrick <[email protected]>

cmd/buildlet/buildlet.go

@@ -71,7 +71,9 @@ var (
 //    8: mac screensaver disabled
 //   11: move from self-signed cert to LetsEncrypt (Issue 16442)
 //   15: ssh support
-const buildletVersion = 15
+//   16: make macstadium builders always haltEntireOS
+//   17: make macstadium halts use sudo
+const buildletVersion = 17
 
 func defaultListenAddr() string {
 	if runtime.GOOS == "darwin" {
@@ -1160,7 +1162,7 @@ func doHalt() {
 	case "darwin":
 		if os.Getenv("GO_BUILDER_ENV") == "macstadium_vm" {
 			// Fast, sloppy, unsafe, because we're never reusing this VM again.
-			err = exec.Command("/sbin/halt", "-n", "-q", "-l").Run()
+			err = exec.Command("/usr/bin/sudo", "/sbin/halt", "-n", "-q", "-l").Run()
 		} else {
 			err = errors.New("not respecting -halt flag on macOS in unknown environment")
 		}
@@ -1565,7 +1567,7 @@ func killProcessTreeUnix(p *os.Process) error {
 // configureMacStadium configures the buildlet flags for use on a Mac
 // VM running on MacStadium under VMWare.
 func configureMacStadium() {
-	*haltEntireOS = false // for now
+	*haltEntireOS = true
 
 	// TODO: setup RAM disk for tmp and set *workDir
 
@@ -1581,12 +1583,6 @@ func configureMacStadium() {
 		log.Fatalf("unsupported sw_vers version %q", version)
 	}
 	major, minor := m[1], m[2] // "10", "12"
-	if minor == "12" {
-		// macOS Sierra wedges its network stack if it runs
-		// all.bash a few times in a row. Reboot between each
-		// build.
-		*haltEntireOS = true
-	}
 	*reverse = "darwin-amd64-" + major + "_" + minor
 	*coordinator = "farmer.golang.org:443"