misc/ios/go_darwin_arm_exec.go - go - Git at Google

 // Copyright 2015 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 // This program can be used as go_darwin_arm_exec by the Go tool.
 // It executes binaries on an iOS device using the XCode toolchain
 // and the ios-deploy program: https://github.com/phonegap/ios-deploy
 package main

 import (
 	"bytes"
 	"errors"
 	"flag"
 	"fmt"
 	"go/build"
 	"io/ioutil"
 	"log"
 	"os"
 	"os/exec"
 	"path/filepath"
 	"runtime"
 	"strings"
 	"sync"
 	"time"
 )

 const debug = false

 var errRetry = errors.New("failed to start test harness (retry attempted)")

 var tmpdir string

 func main() {
 	log.SetFlags(0)
 	log.SetPrefix("go_darwin_arm_exec: ")
 	if debug {
 		log.Println(strings.Join(os.Args, " "))
 	}
 	if len(os.Args) < 2 {
 		log.Fatal("usage: go_darwin_arm_exec a.out")
 	}

 	var err error
 	tmpdir, err = ioutil.TempDir("", "go_darwin_arm_exec_")
 	if err != nil {
 		log.Fatal(err)
 	}

 	// Approximately 1 in a 100 binaries fail to start. If it happens,
 	// try again. These failures happen for several reasons beyond
 	// our control, but all of them are safe to retry as they happen
 	// before lldb encounters the initial getwd breakpoint. As we
 	// know the tests haven't started, we are not hiding flaky tests
 	// with this retry.
 	for i := 0; i < 5; i++ {
 		if i > 0 {
 			fmt.Fprintln(os.Stderr, "start timeout, trying again")
 		}
 		err = run(os.Args[1], os.Args[2:])
 		if err == nil || err != errRetry {
 			break
 		}
 	}
 	if !debug {
 		os.RemoveAll(tmpdir)
 	}
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "go_darwin_arm_exec: %v\n", err)
 		os.Exit(1)
 	}
 }

 func run(bin string, args []string) (err error) {
 	appdir := filepath.Join(tmpdir, "gotest.app")
 	os.RemoveAll(appdir)
 	if err := os.MkdirAll(appdir, 0755); err != nil {
 		return err
 	}

 	if err := cp(filepath.Join(appdir, "gotest"), bin); err != nil {
 		return err
 	}

 	entitlementsPath := filepath.Join(tmpdir, "Entitlements.plist")
 	if err := ioutil.WriteFile(entitlementsPath, []byte(entitlementsPlist), 0744); err != nil {
 		return err
 	}
 	if err := ioutil.WriteFile(filepath.Join(appdir, "Info.plist"), []byte(infoPlist), 0744); err != nil {
 		return err
 	}
 	if err := ioutil.WriteFile(filepath.Join(appdir, "ResourceRules.plist"), []byte(resourceRules), 0744); err != nil {
 		return err
 	}

 	pkgpath, err := copyLocalData(appdir)
 	if err != nil {
 		return err
 	}

 	cmd := exec.Command(
 		"codesign",
 		"-f",
 		"-s", "E8BMC3FE2Z", // certificate associated with golang.org
 		"--entitlements", entitlementsPath,
 		appdir,
 	)
 	if debug {
 		log.Println(strings.Join(cmd.Args, " "))
 	}
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr
 	if err := cmd.Run(); err != nil {
 		return fmt.Errorf("codesign: %v", err)
 	}

 	oldwd, err := os.Getwd()
 	if err != nil {
 		return err
 	}
 	if err := os.Chdir(filepath.Join(appdir, "..")); err != nil {
 		return err
 	}
 	defer os.Chdir(oldwd)

 	type waitPanic struct {
 		err error
 	}
 	defer func() {
 		if r := recover(); r != nil {
 			if w, ok := r.(waitPanic); ok {
 				err = w.err
 				return
 			}
 			panic(r)
 		}
 	}()

 	defer exec.Command("killall", "ios-deploy").Run() // cleanup

 	exec.Command("killall", "ios-deploy").Run()

 	// ios-deploy invokes lldb to give us a shell session with the app.
 	cmd = exec.Command(
 		// lldb tries to be clever with terminals.
 		// So we wrap it in script(1) and be clever
 		// right back at it.
 		"script",
 		"-q", "-t", "0",
 		"/dev/null",

 		"ios-deploy",
 		"--debug",
 		"-u",
 		"-r",
 		"-n",
 		`--args=`+strings.Join(args, " ")+``,
 		"--bundle", appdir,
 	)
 	if debug {
 		log.Println(strings.Join(cmd.Args, " "))
 	}

 	lldbr, lldb, err := os.Pipe()
 	if err != nil {
 		return err
 	}
 	w := new(bufWriter)
 	cmd.Stdout = w
 	cmd.Stderr = w // everything of interest is on stderr
 	cmd.Stdin = lldbr

 	if err := cmd.Start(); err != nil {
 		return fmt.Errorf("ios-deploy failed to start: %v", err)
 	}

 	// Manage the -test.timeout here, outside of the test. There is a lot
 	// of moving parts in an iOS test harness (notably lldb) that can
 	// swallow useful stdio or cause its own ruckus.
 	var timedout chan struct{}
 	if t := parseTimeout(args); t > 1*time.Second {
 		timedout = make(chan struct{})
 		time.AfterFunc(t-1*time.Second, func() {
 			close(timedout)
 		})
 	}

 	exited := make(chan error)
 	go func() {
 		exited <- cmd.Wait()
 	}()

 	waitFor := func(stage, str string, timeout time.Duration) error {
 		select {
 		case <-timedout:
 			w.printBuf()
 			if p := cmd.Process; p != nil {
 				p.Kill()
 			}
 			return fmt.Errorf("timeout (stage %s)", stage)
 		case err := <-exited:
 			w.printBuf()
 			return fmt.Errorf("failed (stage %s): %v", stage, err)
 		case i := <-w.find(str, timeout):
 			if i < 0 {
 				log.Printf("timed out on stage %q, retrying", stage)
 				return errRetry
 			}
 			w.clearTo(i + len(str))
 			return nil
 		}
 	}
 	do := func(cmd string) {
 		fmt.Fprintln(lldb, cmd)
 		if err := waitFor(fmt.Sprintf("prompt after %q", cmd), "(lldb)", 0); err != nil {
 			panic(waitPanic{err})
 		}
 	}

 	// Wait for installation and connection.
 	if err := waitFor("ios-deploy before run", "(lldb)     connect\r\nProcess 0 connected\r\n", 0); err != nil {
 		// Retry if we see a rare and longstanding ios-deploy bug.
 		// https://github.com/phonegap/ios-deploy/issues/11
 		//	Assertion failed: (AMDeviceStartService(device, CFSTR("com.apple.debugserver"), &gdbfd, NULL) == 0)
 		log.Printf("%v, retrying", err)
 		return errRetry
 	}

 	// Script LLDB. Oh dear.
 	do(`process handle SIGHUP  --stop false --pass true --notify false`)
 	do(`process handle SIGPIPE --stop false --pass true --notify false`)
 	do(`process handle SIGUSR1 --stop false --pass true --notify false`)
 	do(`process handle SIGSEGV --stop false --pass true --notify false`) // does not work
 	do(`process handle SIGBUS  --stop false --pass true --notify false`) // does not work

 	do(`breakpoint set -n getwd`) // in runtime/cgo/gcc_darwin_arm.go

 	fmt.Fprintln(lldb, `run`)
 	if err := waitFor("br getwd", "stop reason = breakpoint", 20*time.Second); err != nil {
 		// At this point we see several flaky errors from the iOS
 		// build infrastructure. The most common is never reaching
 		// the breakpoint, which we catch with a timeout. Very
 		// occasionally lldb can produce errors like:
 		//
 		//	Breakpoint 1: no locations (pending).
 		//	WARNING:  Unable to resolve breakpoint to any actual locations.
 		//
 		// As no actual test code has been executed by this point,
 		// we treat all errors as recoverable.
 		if err != errRetry {
 			log.Printf("%v, retrying", err)
 			err = errRetry
 		}
 		return err
 	}
 	if err := waitFor("br getwd prompt", "(lldb)", 0); err != nil {
 		return err
 	}

 	// Move the current working directory into the faux gopath.
 	do(`breakpoint delete 1`)
 	do(`expr char* $mem = (char*)malloc(512)`)
 	do(`expr $mem = (char*)getwd($mem, 512)`)
 	do(`expr $mem = (char*)strcat($mem, "/` + pkgpath + `")`)
 	do(`call (void)chdir($mem)`)

 	// Watch for SIGSEGV. Ideally lldb would never break on SIGSEGV.
 	// http://golang.org/issue/10043
 	go func() {
 		<-w.find("stop reason = EXC_BAD_ACCESS", 0)
 		// cannot use do here, as the defer/recover is not available
 		// on this goroutine.
 		fmt.Fprintln(lldb, `bt`)
 		waitFor("finish backtrace", "(lldb)", 0)
 		w.printBuf()
 		if p := cmd.Process; p != nil {
 			p.Kill()
 		}
 	}()

 	// Run the tests.
 	w.trimSuffix("(lldb) ")
 	fmt.Fprintln(lldb, `process continue`)

 	// Wait for the test to complete.
 	select {
 	case <-timedout:
 		w.printBuf()
 		if p := cmd.Process; p != nil {
 			p.Kill()
 		}
 		return errors.New("timeout running tests")
 	case err := <-exited:
 		// The returned lldb error code is usually non-zero.
 		// We check for test success by scanning for the final
 		// PASS returned by the test harness, assuming the worst
 		// in its absence.
 		if w.isPass() {
 			err = nil
 		} else if err == nil {
 			err = errors.New("test failure")
 		}
 		w.printBuf()
 		return err
 	}
 }

 type bufWriter struct {
 	mu     sync.Mutex
 	buf    []byte
 	suffix []byte // remove from each Write

 	findTxt   []byte   // search buffer on each Write
 	findCh    chan int // report find position
 	findAfter *time.Timer
 }

 func (w *bufWriter) Write(in []byte) (n int, err error) {
 	w.mu.Lock()
 	defer w.mu.Unlock()

 	n = len(in)
 	in = bytes.TrimSuffix(in, w.suffix)

 	w.buf = append(w.buf, in...)

 	if len(w.findTxt) > 0 {
 		if i := bytes.Index(w.buf, w.findTxt); i >= 0 {
 			w.findCh <- i
 			close(w.findCh)
 			w.findTxt = nil
 			w.findCh = nil
 			if w.findAfter != nil {
 				w.findAfter.Stop()
 				w.findAfter = nil
 			}
 		}
 	}
 	return n, nil
 }

 func (w *bufWriter) trimSuffix(p string) {
 	w.mu.Lock()
 	defer w.mu.Unlock()
 	w.suffix = []byte(p)
 }

 func (w *bufWriter) printBuf() {
 	w.mu.Lock()
 	defer w.mu.Unlock()
 	fmt.Fprintf(os.Stderr, "%s", w.buf)
 	w.buf = nil
 }

 func (w *bufWriter) clearTo(i int) {
 	w.mu.Lock()
 	defer w.mu.Unlock()
 	if debug {
 		fmt.Fprintf(os.Stderr, "--- go_darwin_arm_exec clear ---\n%s\n--- go_darwin_arm_exec clear ---\n", w.buf[:i])
 	}
 	w.buf = w.buf[i:]
 }

 // find returns a channel that will have exactly one byte index sent
 // to it when the text str appears in the buffer. If the text does not
 // appear before timeout, -1 is sent.
 //
 // A timeout of zero means no timeout.
 func (w *bufWriter) find(str string, timeout time.Duration) <-chan int {
 	w.mu.Lock()
 	defer w.mu.Unlock()
 	if len(w.findTxt) > 0 {
 		panic(fmt.Sprintf("find(%s): already trying to find %s", str, w.findTxt))
 	}
 	txt := []byte(str)
 	ch := make(chan int, 1)
 	if i := bytes.Index(w.buf, txt); i >= 0 {
 		ch <- i
 		close(ch)
 	} else {
 		w.findTxt = txt
 		w.findCh = ch
 		if timeout > 0 {
 			w.findAfter = time.AfterFunc(timeout, func() {
 				w.mu.Lock()
 				defer w.mu.Unlock()
 				if w.findCh == ch {
 					w.findTxt = nil
 					w.findCh = nil
 					w.findAfter = nil
 					ch <- -1
 					close(ch)
 				}
 			})
 		}
 	}
 	return ch
 }

 func (w *bufWriter) isPass() bool {
 	w.mu.Lock()
 	defer w.mu.Unlock()

 	// The final stdio of lldb is non-deterministic, so we
 	// scan the whole buffer.
 	//
 	// Just to make things fun, lldb sometimes translates \n
 	// into \r\n.
 	return bytes.Contains(w.buf, []byte("\nPASS\n")) || bytes.Contains(w.buf, []byte("\nPASS\r"))
 }

 func parseTimeout(testArgs []string) (timeout time.Duration) {
 	var args []string
 	for _, arg := range testArgs {
 		if strings.Contains(arg, "test.timeout") {
 			args = append(args, arg)
 		}
 	}
 	f := flag.NewFlagSet("", flag.ContinueOnError)
 	f.DurationVar(&timeout, "test.timeout", 0, "")
 	f.Parse(args)
 	if debug {
 		log.Printf("parseTimeout of %s, got %s", args, timeout)
 	}
 	return timeout
 }

 func copyLocalDir(dst, src string) error {
 	if err := os.Mkdir(dst, 0755); err != nil {
 		return err
 	}

 	d, err := os.Open(src)
 	if err != nil {
 		return err
 	}
 	defer d.Close()
 	fi, err := d.Readdir(-1)
 	if err != nil {
 		return err
 	}

 	for _, f := range fi {
 		if f.IsDir() {
 			if f.Name() == "testdata" {
 				if err := cp(dst, filepath.Join(src, f.Name())); err != nil {
 					return err
 				}
 			}
 			continue
 		}
 		if err := cp(dst, filepath.Join(src, f.Name())); err != nil {
 			return err
 		}
 	}
 	return nil
 }

 func cp(dst, src string) error {
 	out, err := exec.Command("cp", "-a", src, dst).CombinedOutput()
 	if err != nil {
 		os.Stderr.Write(out)
 	}
 	return err
 }

 func copyLocalData(dstbase string) (pkgpath string, err error) {
 	cwd, err := os.Getwd()
 	if err != nil {
 		return "", err
 	}

 	finalPkgpath, underGoRoot, err := subdir()
 	if err != nil {
 		return "", err
 	}
 	cwd = strings.TrimSuffix(cwd, finalPkgpath)

 	// Copy all immediate files and testdata directories between
 	// the package being tested and the source root.
 	pkgpath = ""
 	for _, element := range strings.Split(finalPkgpath, string(filepath.Separator)) {
 		if debug {
 			log.Printf("copying %s", pkgpath)
 		}
 		pkgpath = filepath.Join(pkgpath, element)
 		dst := filepath.Join(dstbase, pkgpath)
 		src := filepath.Join(cwd, pkgpath)
 		if err := copyLocalDir(dst, src); err != nil {
 			return "", err
 		}
 	}

 	// Copy timezone file.
 	//
 	// Typical apps have the zoneinfo.zip in the root of their app bundle,
 	// read by the time package as the working directory at initialization.
 	// As we move the working directory to the GOROOT pkg directory, we
 	// install the zoneinfo.zip file in the pkgpath.
 	if underGoRoot {
 		err := cp(
 			filepath.Join(dstbase, pkgpath),
 			filepath.Join(cwd, "lib", "time", "zoneinfo.zip"),
 		)
 		if err != nil {
 			return "", err
 		}
 	}

 	return finalPkgpath, nil
 }

 // subdir determines the package based on the current working directory,
 // and returns the path to the package source relative to $GOROOT (or $GOPATH).
 func subdir() (pkgpath string, underGoRoot bool, err error) {
 	cwd, err := os.Getwd()
 	if err != nil {
 		return "", false, err
 	}
 	if root := runtime.GOROOT(); strings.HasPrefix(cwd, root) {
 		subdir, err := filepath.Rel(root, cwd)
 		if err != nil {
 			return "", false, err
 		}
 		return subdir, true, nil
 	}

 	for _, p := range filepath.SplitList(build.Default.GOPATH) {
 		if !strings.HasPrefix(cwd, p) {
 			continue
 		}
 		subdir, err := filepath.Rel(p, cwd)
 		if err == nil {
 			return subdir, false, nil
 		}
 	}
 	return "", false, fmt.Errorf(
 		"working directory %q is not in either GOROOT(%q) or GOPATH(%q)",
 		cwd,
 		runtime.GOROOT(),
 		build.Default.GOPATH,
 	)
 }

 const infoPlist = `<?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
 <dict>
 <key>CFBundleName</key><string>golang.gotest</string>
 <key>CFBundleSupportedPlatforms</key><array><string>iPhoneOS</string></array>
 <key>CFBundleExecutable</key><string>gotest</string>
 <key>CFBundleVersion</key><string>1.0</string>
 <key>CFBundleIdentifier</key><string>golang.gotest</string>
 <key>CFBundleResourceSpecification</key><string>ResourceRules.plist</string>
 <key>LSRequiresIPhoneOS</key><true/>
 <key>CFBundleDisplayName</key><string>gotest</string>
 </dict>
 </plist>
 `

 const devID = `YE84DJ86AZ`

 const entitlementsPlist = `<?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
 <dict>
 	<key>keychain-access-groups</key>
 	<array><string>` + devID + `.golang.gotest</string></array>
 	<key>get-task-allow</key>
 	<true/>
 	<key>application-identifier</key>
 	<string>` + devID + `.golang.gotest</string>
 	<key>com.apple.developer.team-identifier</key>
 	<string>` + devID + `</string>
 </dict>
 </plist>`

 const resourceRules = `<?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
 <dict>
         <key>rules</key>
         <dict>
                 <key>.*</key><true/>
 		<key>Info.plist</key>
 		<dict>
 			<key>omit</key> <true/>
 			<key>weight</key> <real>10</real>
 		</dict>
 		<key>ResourceRules.plist</key>
 		<dict>
 			<key>omit</key> <true/>
 			<key>weight</key> <real>100</real>
 		</dict>
 	</dict>
 </dict>
 </plist>
 `
	// Copyright 2015 The Go Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	// This program can be used as go_darwin_arm_exec by the Go tool.
	// It executes binaries on an iOS device using the XCode toolchain
	// and the ios-deploy program: https://github.com/phonegap/ios-deploy
	package main

	import (
	"bytes"
	"errors"
	"flag"
	"fmt"
	"go/build"
	"io/ioutil"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"strings"
	"sync"
	"time"
	)

	const debug = false

	var errRetry = errors.New("failed to start test harness (retry attempted)")

	var tmpdir string

	func main() {
	log.SetFlags(0)
	log.SetPrefix("go_darwin_arm_exec: ")
	if debug {
	log.Println(strings.Join(os.Args, " "))
	}
	if len(os.Args) < 2 {
	log.Fatal("usage: go_darwin_arm_exec a.out")
	}

	var err error
	tmpdir, err = ioutil.TempDir("", "go_darwin_arm_exec_")
	if err != nil {
	log.Fatal(err)
	}

	// Approximately 1 in a 100 binaries fail to start. If it happens,
	// try again. These failures happen for several reasons beyond
	// our control, but all of them are safe to retry as they happen
	// before lldb encounters the initial getwd breakpoint. As we
	// know the tests haven't started, we are not hiding flaky tests
	// with this retry.
	for i := 0; i < 5; i++ {
	if i > 0 {
	fmt.Fprintln(os.Stderr, "start timeout, trying again")
	}
	err = run(os.Args[1], os.Args[2:])
	if err == nil \|\| err != errRetry {
	break
	}
	}
	if !debug {
	os.RemoveAll(tmpdir)
	}
	if err != nil {
	fmt.Fprintf(os.Stderr, "go_darwin_arm_exec: %v\n", err)
	os.Exit(1)
	}
	}

	func run(bin string, args []string) (err error) {
	appdir := filepath.Join(tmpdir, "gotest.app")
	os.RemoveAll(appdir)
	if err := os.MkdirAll(appdir, 0755); err != nil {
	return err
	}

	if err := cp(filepath.Join(appdir, "gotest"), bin); err != nil {
	return err
	}

	entitlementsPath := filepath.Join(tmpdir, "Entitlements.plist")
	if err := ioutil.WriteFile(entitlementsPath, []byte(entitlementsPlist), 0744); err != nil {
	return err
	}
	if err := ioutil.WriteFile(filepath.Join(appdir, "Info.plist"), []byte(infoPlist), 0744); err != nil {
	return err
	}
	if err := ioutil.WriteFile(filepath.Join(appdir, "ResourceRules.plist"), []byte(resourceRules), 0744); err != nil {
	return err
	}

	pkgpath, err := copyLocalData(appdir)
	if err != nil {
	return err
	}

	cmd := exec.Command(
	"codesign",
	"-f",
	"-s", "E8BMC3FE2Z", // certificate associated with golang.org
	"--entitlements", entitlementsPath,
	appdir,
	)
	if debug {
	log.Println(strings.Join(cmd.Args, " "))
	}
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	if err := cmd.Run(); err != nil {
	return fmt.Errorf("codesign: %v", err)
	}

	oldwd, err := os.Getwd()
	if err != nil {
	return err
	}
	if err := os.Chdir(filepath.Join(appdir, "..")); err != nil {
	return err
	}
	defer os.Chdir(oldwd)

	type waitPanic struct {
	err error
	}
	defer func() {
	if r := recover(); r != nil {
	if w, ok := r.(waitPanic); ok {
	err = w.err
	return
	}
	panic(r)
	}
	}()

	defer exec.Command("killall", "ios-deploy").Run() // cleanup

	exec.Command("killall", "ios-deploy").Run()

	// ios-deploy invokes lldb to give us a shell session with the app.
	cmd = exec.Command(
	// lldb tries to be clever with terminals.
	// So we wrap it in script(1) and be clever
	// right back at it.
	"script",
	"-q", "-t", "0",
	"/dev/null",

	"ios-deploy",
	"--debug",
	"-u",
	"-r",
	"-n",
	`--args=`+strings.Join(args, " ")+``,
	"--bundle", appdir,
	)
	if debug {
	log.Println(strings.Join(cmd.Args, " "))
	}

	lldbr, lldb, err := os.Pipe()
	if err != nil {
	return err
	}
	w := new(bufWriter)
	cmd.Stdout = w
	cmd.Stderr = w // everything of interest is on stderr
	cmd.Stdin = lldbr

	if err := cmd.Start(); err != nil {
	return fmt.Errorf("ios-deploy failed to start: %v", err)
	}

	// Manage the -test.timeout here, outside of the test. There is a lot
	// of moving parts in an iOS test harness (notably lldb) that can
	// swallow useful stdio or cause its own ruckus.
	var timedout chan struct{}
	if t := parseTimeout(args); t > 1*time.Second {
	timedout = make(chan struct{})
	time.AfterFunc(t-1*time.Second, func() {
	close(timedout)
	})
	}

	exited := make(chan error)
	go func() {
	exited <- cmd.Wait()
	}()

	waitFor := func(stage, str string, timeout time.Duration) error {
	select {
	case <-timedout:
	w.printBuf()
	if p := cmd.Process; p != nil {
	p.Kill()
	}
	return fmt.Errorf("timeout (stage %s)", stage)
	case err := <-exited:
	w.printBuf()
	return fmt.Errorf("failed (stage %s): %v", stage, err)
	case i := <-w.find(str, timeout):
	if i < 0 {
	log.Printf("timed out on stage %q, retrying", stage)
	return errRetry
	}
	w.clearTo(i + len(str))
	return nil
	}
	}
	do := func(cmd string) {
	fmt.Fprintln(lldb, cmd)
	if err := waitFor(fmt.Sprintf("prompt after %q", cmd), "(lldb)", 0); err != nil {
	panic(waitPanic{err})
	}
	}

	// Wait for installation and connection.
	if err := waitFor("ios-deploy before run", "(lldb) connect\r\nProcess 0 connected\r\n", 0); err != nil {
	// Retry if we see a rare and longstanding ios-deploy bug.
	// https://github.com/phonegap/ios-deploy/issues/11
	// Assertion failed: (AMDeviceStartService(device, CFSTR("com.apple.debugserver"), &gdbfd, NULL) == 0)
	log.Printf("%v, retrying", err)
	return errRetry
	}

	// Script LLDB. Oh dear.
	do(`process handle SIGHUP --stop false --pass true --notify false`)
	do(`process handle SIGPIPE --stop false --pass true --notify false`)
	do(`process handle SIGUSR1 --stop false --pass true --notify false`)
	do(`process handle SIGSEGV --stop false --pass true --notify false`) // does not work
	do(`process handle SIGBUS --stop false --pass true --notify false`) // does not work

	do(`breakpoint set -n getwd`) // in runtime/cgo/gcc_darwin_arm.go

	fmt.Fprintln(lldb, `run`)
	if err := waitFor("br getwd", "stop reason = breakpoint", 20*time.Second); err != nil {
	// At this point we see several flaky errors from the iOS
	// build infrastructure. The most common is never reaching
	// the breakpoint, which we catch with a timeout. Very
	// occasionally lldb can produce errors like:
	//
	// Breakpoint 1: no locations (pending).
	// WARNING: Unable to resolve breakpoint to any actual locations.
	//
	// As no actual test code has been executed by this point,
	// we treat all errors as recoverable.
	if err != errRetry {
	log.Printf("%v, retrying", err)
	err = errRetry
	}
	return err
	}
	if err := waitFor("br getwd prompt", "(lldb)", 0); err != nil {
	return err
	}

	// Move the current working directory into the faux gopath.
	do(`breakpoint delete 1`)
	do(`expr char* $mem = (char*)malloc(512)`)
	do(`expr $mem = (char*)getwd($mem, 512)`)
	do(`expr $mem = (char*)strcat($mem, "/` + pkgpath + `")`)
	do(`call (void)chdir($mem)`)

	// Watch for SIGSEGV. Ideally lldb would never break on SIGSEGV.
	// http://golang.org/issue/10043
	go func() {
	<-w.find("stop reason = EXC_BAD_ACCESS", 0)
	// cannot use do here, as the defer/recover is not available
	// on this goroutine.
	fmt.Fprintln(lldb, `bt`)
	waitFor("finish backtrace", "(lldb)", 0)
	w.printBuf()
	if p := cmd.Process; p != nil {
	p.Kill()
	}
	}()

	// Run the tests.
	w.trimSuffix("(lldb) ")
	fmt.Fprintln(lldb, `process continue`)

	// Wait for the test to complete.
	select {
	case <-timedout:
	w.printBuf()
	if p := cmd.Process; p != nil {
	p.Kill()
	}
	return errors.New("timeout running tests")
	case err := <-exited:
	// The returned lldb error code is usually non-zero.
	// We check for test success by scanning for the final
	// PASS returned by the test harness, assuming the worst
	// in its absence.
	if w.isPass() {
	err = nil
	} else if err == nil {
	err = errors.New("test failure")
	}
	w.printBuf()
	return err
	}
	}

	type bufWriter struct {
	mu sync.Mutex
	buf []byte
	suffix []byte // remove from each Write

	findTxt []byte // search buffer on each Write
	findCh chan int // report find position
	findAfter *time.Timer
	}

	func (w *bufWriter) Write(in []byte) (n int, err error) {
	w.mu.Lock()
	defer w.mu.Unlock()

	n = len(in)
	in = bytes.TrimSuffix(in, w.suffix)

	w.buf = append(w.buf, in...)

	if len(w.findTxt) > 0 {
	if i := bytes.Index(w.buf, w.findTxt); i >= 0 {
	w.findCh <- i
	close(w.findCh)
	w.findTxt = nil
	w.findCh = nil
	if w.findAfter != nil {
	w.findAfter.Stop()
	w.findAfter = nil
	}
	}
	}
	return n, nil
	}

	func (w *bufWriter) trimSuffix(p string) {
	w.mu.Lock()
	defer w.mu.Unlock()
	w.suffix = []byte(p)
	}

	func (w *bufWriter) printBuf() {
	w.mu.Lock()
	defer w.mu.Unlock()
	fmt.Fprintf(os.Stderr, "%s", w.buf)
	w.buf = nil
	}

	func (w *bufWriter) clearTo(i int) {
	w.mu.Lock()
	defer w.mu.Unlock()
	if debug {
	fmt.Fprintf(os.Stderr, "--- go_darwin_arm_exec clear ---\n%s\n--- go_darwin_arm_exec clear ---\n", w.buf[:i])
	}
	w.buf = w.buf[i:]
	}

	// find returns a channel that will have exactly one byte index sent
	// to it when the text str appears in the buffer. If the text does not
	// appear before timeout, -1 is sent.
	//
	// A timeout of zero means no timeout.
	func (w *bufWriter) find(str string, timeout time.Duration) <-chan int {
	w.mu.Lock()
	defer w.mu.Unlock()
	if len(w.findTxt) > 0 {
	panic(fmt.Sprintf("find(%s): already trying to find %s", str, w.findTxt))
	}
	txt := []byte(str)
	ch := make(chan int, 1)
	if i := bytes.Index(w.buf, txt); i >= 0 {
	ch <- i
	close(ch)
	} else {
	w.findTxt = txt
	w.findCh = ch
	if timeout > 0 {
	w.findAfter = time.AfterFunc(timeout, func() {
	w.mu.Lock()
	defer w.mu.Unlock()
	if w.findCh == ch {
	w.findTxt = nil
	w.findCh = nil
	w.findAfter = nil
	ch <- -1
	close(ch)
	}
	})
	}
	}
	return ch
	}

	func (w *bufWriter) isPass() bool {
	w.mu.Lock()
	defer w.mu.Unlock()

	// The final stdio of lldb is non-deterministic, so we
	// scan the whole buffer.
	//
	// Just to make things fun, lldb sometimes translates \n
	// into \r\n.
	return bytes.Contains(w.buf, []byte("\nPASS\n")) \|\| bytes.Contains(w.buf, []byte("\nPASS\r"))
	}

	func parseTimeout(testArgs []string) (timeout time.Duration) {
	var args []string
	for _, arg := range testArgs {
	if strings.Contains(arg, "test.timeout") {
	args = append(args, arg)
	}
	}
	f := flag.NewFlagSet("", flag.ContinueOnError)
	f.DurationVar(&timeout, "test.timeout", 0, "")
	f.Parse(args)
	if debug {
	log.Printf("parseTimeout of %s, got %s", args, timeout)
	}
	return timeout
	}

	func copyLocalDir(dst, src string) error {
	if err := os.Mkdir(dst, 0755); err != nil {
	return err
	}

	d, err := os.Open(src)
	if err != nil {
	return err
	}
	defer d.Close()
	fi, err := d.Readdir(-1)
	if err != nil {
	return err
	}

	for _, f := range fi {
	if f.IsDir() {
	if f.Name() == "testdata" {
	if err := cp(dst, filepath.Join(src, f.Name())); err != nil {
	return err
	}
	}
	continue
	}
	if err := cp(dst, filepath.Join(src, f.Name())); err != nil {
	return err
	}
	}
	return nil
	}

	func cp(dst, src string) error {
	out, err := exec.Command("cp", "-a", src, dst).CombinedOutput()
	if err != nil {
	os.Stderr.Write(out)
	}
	return err
	}

	func copyLocalData(dstbase string) (pkgpath string, err error) {
	cwd, err := os.Getwd()
	if err != nil {
	return "", err
	}

	finalPkgpath, underGoRoot, err := subdir()
	if err != nil {
	return "", err
	}
	cwd = strings.TrimSuffix(cwd, finalPkgpath)

	// Copy all immediate files and testdata directories between
	// the package being tested and the source root.
	pkgpath = ""
	for _, element := range strings.Split(finalPkgpath, string(filepath.Separator)) {
	if debug {
	log.Printf("copying %s", pkgpath)
	}
	pkgpath = filepath.Join(pkgpath, element)
	dst := filepath.Join(dstbase, pkgpath)
	src := filepath.Join(cwd, pkgpath)
	if err := copyLocalDir(dst, src); err != nil {
	return "", err
	}
	}

	// Copy timezone file.
	//
	// Typical apps have the zoneinfo.zip in the root of their app bundle,
	// read by the time package as the working directory at initialization.
	// As we move the working directory to the GOROOT pkg directory, we
	// install the zoneinfo.zip file in the pkgpath.
	if underGoRoot {
	err := cp(
	filepath.Join(dstbase, pkgpath),
	filepath.Join(cwd, "lib", "time", "zoneinfo.zip"),
	)
	if err != nil {
	return "", err
	}
	}

	return finalPkgpath, nil
	}

	// subdir determines the package based on the current working directory,
	// and returns the path to the package source relative to $GOROOT (or $GOPATH).
	func subdir() (pkgpath string, underGoRoot bool, err error) {
	cwd, err := os.Getwd()
	if err != nil {
	return "", false, err
	}
	if root := runtime.GOROOT(); strings.HasPrefix(cwd, root) {
	subdir, err := filepath.Rel(root, cwd)
	if err != nil {
	return "", false, err
	}
	return subdir, true, nil
	}

	for _, p := range filepath.SplitList(build.Default.GOPATH) {
	if !strings.HasPrefix(cwd, p) {
	continue
	}
	subdir, err := filepath.Rel(p, cwd)
	if err == nil {
	return subdir, false, nil
	}
	}
	return "", false, fmt.Errorf(
	"working directory %q is not in either GOROOT(%q) or GOPATH(%q)",
	cwd,
	runtime.GOROOT(),
	build.Default.GOPATH,
	)
	}

	const infoPlist = `<?xml version="1.0" encoding="UTF-8"?>
	<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
	<plist version="1.0">
	<dict>
	<key>CFBundleName</key><string>golang.gotest</string>
	<key>CFBundleSupportedPlatforms</key><array><string>iPhoneOS</string></array>
	<key>CFBundleExecutable</key><string>gotest</string>
	<key>CFBundleVersion</key><string>1.0</string>
	<key>CFBundleIdentifier</key><string>golang.gotest</string>
	<key>CFBundleResourceSpecification</key><string>ResourceRules.plist</string>
	<key>LSRequiresIPhoneOS</key><true/>
	<key>CFBundleDisplayName</key><string>gotest</string>
	</dict>
	</plist>
	`

	const devID = `YE84DJ86AZ`

	const entitlementsPlist = `<?xml version="1.0" encoding="UTF-8"?>
	<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
	<plist version="1.0">
	<dict>
	<key>keychain-access-groups</key>
	<array><string>` + devID + `.golang.gotest</string></array>
	<key>get-task-allow</key>
	<true/>
	<key>application-identifier</key>
	<string>` + devID + `.golang.gotest</string>
	<key>com.apple.developer.team-identifier</key>
	<string>` + devID + `</string>
	</dict>
	</plist>`

	const resourceRules = `<?xml version="1.0" encoding="UTF-8"?>
	<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
	<plist version="1.0">
	<dict>
	<key>rules</key>
	<dict>
	<key>.*</key><true/>
	<key>Info.plist</key>
	<dict>
	<key>omit</key> <true/>
	<key>weight</key> <real>10</real>
	</dict>
	<key>ResourceRules.plist</key>
	<dict>
	<key>omit</key> <true/>
	<key>weight</key> <real>100</real>
	</dict>
	</dict>
	</dict>
	</plist>
	`