misc/cgo/testcshared/cshared_test.go - go - Git at Google

 // Copyright 2017 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.

 package cshared_test

 import (
 	"debug/elf"
 	"fmt"
 	"io/ioutil"
 	"log"
 	"os"
 	"os/exec"
 	"path"
 	"path/filepath"
 	"strings"
 	"sync"
 	"testing"
 	"unicode"
 )

 // C compiler with args (from $(go env CC) $(go env GOGCCFLAGS)).
 var cc []string

 // An environment with GOPATH=$(pwd).
 var gopathEnv []string

 // ".exe" on Windows.
 var exeSuffix string

 var GOOS, GOARCH, GOROOT string
 var installdir, androiddir string
 var libSuffix, libgoname string

 func TestMain(m *testing.M) {
 	GOOS = goEnv("GOOS")
 	GOARCH = goEnv("GOARCH")
 	GOROOT = goEnv("GOROOT")

 	if _, err := os.Stat(GOROOT); os.IsNotExist(err) {
 		log.Fatalf("Unable able to find GOROOT at '%s'", GOROOT)
 	}

 	// Directory where cgo headers and outputs will be installed.
 	// The installation directory format varies depending on the platform.
 	installdir = path.Join("pkg", fmt.Sprintf("%s_%s_testcshared", GOOS, GOARCH))
 	switch GOOS {
 	case "darwin":
 		libSuffix = "dylib"
 	case "windows":
 		libSuffix = "dll"
 	default:
 		libSuffix = "so"
 		installdir = path.Join("pkg", fmt.Sprintf("%s_%s_testcshared_shared", GOOS, GOARCH))
 	}

 	androiddir = fmt.Sprintf("/data/local/tmp/testcshared-%d", os.Getpid())
 	if GOOS == "android" {
 		args := append(adbCmd(), "shell", "mkdir", "-p", androiddir)
 		cmd := exec.Command(args[0], args[1:]...)
 		out, err := cmd.CombinedOutput()
 		if err != nil {
 			log.Fatalf("setupAndroid failed: %v\n%s\n", err, out)
 		}
 	}

 	libgoname = "libgo." + libSuffix

 	cc = []string{goEnv("CC")}

 	out := goEnv("GOGCCFLAGS")
 	quote := '\000'
 	start := 0
 	lastSpace := true
 	backslash := false
 	s := string(out)
 	for i, c := range s {
 		if quote == '\000' && unicode.IsSpace(c) {
 			if !lastSpace {
 				cc = append(cc, s[start:i])
 				lastSpace = true
 			}
 		} else {
 			if lastSpace {
 				start = i
 				lastSpace = false
 			}
 			if quote == '\000' && !backslash && (c == '"' || c == '\'') {
 				quote = c
 				backslash = false
 			} else if !backslash && quote == c {
 				quote = '\000'
 			} else if (quote == '\000' || quote == '"') && !backslash && c == '\\' {
 				backslash = true
 			} else {
 				backslash = false
 			}
 		}
 	}
 	if !lastSpace {
 		cc = append(cc, s[start:])
 	}

 	switch GOOS {
 	case "darwin":
 		// For Darwin/ARM.
 		// TODO(crawshaw): can we do better?
 		cc = append(cc, []string{"-framework", "CoreFoundation", "-framework", "Foundation"}...)
 	case "android":
 		cc = append(cc, "-pie", "-fuse-ld=gold")
 	}
 	libgodir := GOOS + "_" + GOARCH
 	switch GOOS {
 	case "darwin":
 		if GOARCH == "arm" || GOARCH == "arm64" {
 			libgodir += "_shared"
 		}
 	case "dragonfly", "freebsd", "linux", "netbsd", "openbsd", "solaris":
 		libgodir += "_shared"
 	}
 	cc = append(cc, "-I", filepath.Join("pkg", libgodir))

 	// Build an environment with GOPATH=$(pwd)
 	dir, err := os.Getwd()
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(2)
 	}
 	gopathEnv = append(os.Environ(), "GOPATH="+dir)

 	if GOOS == "windows" {
 		exeSuffix = ".exe"
 	}

 	st := m.Run()

 	os.Remove(libgoname)
 	os.RemoveAll("pkg")
 	cleanupHeaders()
 	cleanupAndroid()

 	os.Exit(st)
 }

 func goEnv(key string) string {
 	out, err := exec.Command("go", "env", key).Output()
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "go env %s failed:\n%s", key, err)
 		fmt.Fprintf(os.Stderr, "%s", err.(*exec.ExitError).Stderr)
 		os.Exit(2)
 	}
 	return strings.TrimSpace(string(out))
 }

 func cmdToRun(name string) string {
 	return "./" + name + exeSuffix
 }

 func adbCmd() []string {
 	cmd := []string{"adb"}
 	if flags := os.Getenv("GOANDROID_ADB_FLAGS"); flags != "" {
 		cmd = append(cmd, strings.Split(flags, " ")...)
 	}
 	return cmd
 }

 func adbPush(t *testing.T, filename string) {
 	if GOOS != "android" {
 		return
 	}
 	args := append(adbCmd(), "push", filename, fmt.Sprintf("%s/%s", androiddir, filename))
 	cmd := exec.Command(args[0], args[1:]...)
 	if out, err := cmd.CombinedOutput(); err != nil {
 		t.Fatalf("adb command failed: %v\n%s\n", err, out)
 	}
 }

 func adbRun(t *testing.T, env []string, adbargs ...string) string {
 	if GOOS != "android" {
 		t.Fatalf("trying to run adb command when operating system is not android.")
 	}
 	args := append(adbCmd(), "shell")
 	// Propagate LD_LIBRARY_PATH to the adb shell invocation.
 	for _, e := range env {
 		if strings.Index(e, "LD_LIBRARY_PATH=") != -1 {
 			adbargs = append([]string{e}, adbargs...)
 			break
 		}
 	}
 	shellcmd := fmt.Sprintf("cd %s; %s", androiddir, strings.Join(adbargs, " "))
 	args = append(args, shellcmd)
 	cmd := exec.Command(args[0], args[1:]...)
 	out, err := cmd.CombinedOutput()
 	if err != nil {
 		t.Fatalf("adb command failed: %v\n%s\n", err, out)
 	}
 	return strings.Replace(string(out), "\r", "", -1)
 }

 func run(t *testing.T, env []string, args ...string) string {
 	t.Helper()
 	cmd := exec.Command(args[0], args[1:]...)
 	cmd.Env = env

 	if GOOS != "windows" {
 		// TestUnexportedSymbols relies on file descriptor 30
 		// being closed when the program starts, so enforce
 		// that in all cases. (The first three descriptors are
 		// stdin/stdout/stderr, so we just need to make sure
 		// that cmd.ExtraFiles[27] exists and is nil.)
 		cmd.ExtraFiles = make([]*os.File, 28)
 	}

 	out, err := cmd.CombinedOutput()
 	if err != nil {
 		t.Fatalf("command failed: %v\n%v\n%s\n", args, err, out)
 	} else {
 		t.Logf("run: %v", args)
 	}
 	return string(out)
 }

 func runExe(t *testing.T, env []string, args ...string) string {
 	t.Helper()
 	if GOOS == "android" {
 		return adbRun(t, env, args...)
 	}
 	return run(t, env, args...)
 }

 func runCC(t *testing.T, args ...string) string {
 	t.Helper()
 	// This function is run in parallel, so append to a copy of cc
 	// rather than cc itself.
 	return run(t, nil, append(append([]string(nil), cc...), args...)...)
 }

 func createHeaders() error {
 	args := []string{"go", "install", "-i", "-buildmode=c-shared",
 		"-installsuffix", "testcshared", "libgo"}
 	cmd := exec.Command(args[0], args[1:]...)
 	cmd.Env = gopathEnv
 	out, err := cmd.CombinedOutput()
 	if err != nil {
 		return fmt.Errorf("command failed: %v\n%v\n%s\n", args, err, out)
 	}

 	args = []string{"go", "build", "-buildmode=c-shared",
 		"-installsuffix", "testcshared",
 		"-o", libgoname,
 		filepath.Join("src", "libgo", "libgo.go")}
 	cmd = exec.Command(args[0], args[1:]...)
 	cmd.Env = gopathEnv
 	out, err = cmd.CombinedOutput()
 	if err != nil {
 		return fmt.Errorf("command failed: %v\n%v\n%s\n", args, err, out)
 	}

 	if GOOS == "android" {
 		args = append(adbCmd(), "push", libgoname, fmt.Sprintf("%s/%s", androiddir, libgoname))
 		cmd = exec.Command(args[0], args[1:]...)
 		out, err = cmd.CombinedOutput()
 		if err != nil {
 			return fmt.Errorf("adb command failed: %v\n%s\n", err, out)
 		}
 	}

 	return nil
 }

 var (
 	headersOnce sync.Once
 	headersErr  error
 )

 func createHeadersOnce(t *testing.T) {
 	headersOnce.Do(func() {
 		headersErr = createHeaders()
 	})
 	if headersErr != nil {
 		t.Fatal(headersErr)
 	}
 }

 func cleanupHeaders() {
 	os.Remove("libgo.h")
 }

 func cleanupAndroid() {
 	if GOOS != "android" {
 		return
 	}
 	args := append(adbCmd(), "shell", "rm", "-rf", androiddir)
 	cmd := exec.Command(args[0], args[1:]...)
 	out, err := cmd.CombinedOutput()
 	if err != nil {
 		log.Fatalf("cleanupAndroid failed: %v\n%s\n", err, out)
 	}
 }

 // test0: exported symbols in shared lib are accessible.
 func TestExportedSymbols(t *testing.T) {
 	t.Parallel()

 	cmd := "testp0"
 	bin := cmdToRun(cmd)

 	createHeadersOnce(t)

 	runCC(t, "-I", installdir, "-o", cmd, "main0.c", libgoname)
 	adbPush(t, cmd)

 	defer os.Remove(bin)

 	out := runExe(t, append(gopathEnv, "LD_LIBRARY_PATH=."), bin)
 	if strings.TrimSpace(out) != "PASS" {
 		t.Error(out)
 	}
 }

 // test1: shared library can be dynamically loaded and exported symbols are accessible.
 func TestExportedSymbolsWithDynamicLoad(t *testing.T) {
 	t.Parallel()

 	if GOOS == "windows" {
 		t.Logf("Skipping on %s", GOOS)
 		return
 	}

 	cmd := "testp1"
 	bin := cmdToRun(cmd)

 	createHeadersOnce(t)

 	if GOOS != "freebsd" {
 		runCC(t, "-o", cmd, "main1.c", "-ldl")
 	} else {
 		runCC(t, "-o", cmd, "main1.c")
 	}
 	adbPush(t, cmd)

 	defer os.Remove(bin)

 	out := runExe(t, nil, bin, "./"+libgoname)
 	if strings.TrimSpace(out) != "PASS" {
 		t.Error(out)
 	}
 }

 // test2: tests libgo2 which does not export any functions.
 func TestUnexportedSymbols(t *testing.T) {
 	t.Parallel()

 	if GOOS == "windows" {
 		t.Logf("Skipping on %s", GOOS)
 		return
 	}

 	cmd := "testp2"
 	bin := cmdToRun(cmd)
 	libname := "libgo2." + libSuffix

 	run(t,
 		gopathEnv,
 		"go", "build",
 		"-buildmode=c-shared",
 		"-installsuffix", "testcshared",
 		"-o", libname, "libgo2",
 	)
 	adbPush(t, libname)

 	linkFlags := "-Wl,--no-as-needed"
 	if GOOS == "darwin" {
 		linkFlags = ""
 	}

 	runCC(t, "-o", cmd, "main2.c", linkFlags, libname)
 	adbPush(t, cmd)

 	defer os.Remove(libname)
 	defer os.Remove(bin)

 	out := runExe(t, append(gopathEnv, "LD_LIBRARY_PATH=."), bin)

 	if strings.TrimSpace(out) != "PASS" {
 		t.Error(out)
 	}
 }

 // test3: tests main.main is exported on android.
 func TestMainExportedOnAndroid(t *testing.T) {
 	t.Parallel()

 	switch GOOS {
 	case "android":
 		break
 	default:
 		t.Logf("Skipping on %s", GOOS)
 		return
 	}

 	cmd := "testp3"
 	bin := cmdToRun(cmd)

 	createHeadersOnce(t)

 	runCC(t, "-o", cmd, "main3.c", "-ldl")
 	adbPush(t, cmd)

 	defer os.Remove(bin)

 	out := runExe(t, nil, bin, "./"+libgoname)
 	if strings.TrimSpace(out) != "PASS" {
 		t.Error(out)
 	}
 }

 func testSignalHandlers(t *testing.T, pkgname, cfile, cmd string) {
 	libname := pkgname + "." + libSuffix
 	run(t,
 		gopathEnv,
 		"go", "build",
 		"-buildmode=c-shared",
 		"-installsuffix", "testcshared",
 		"-o", libname, pkgname,
 	)
 	adbPush(t, libname)
 	if GOOS != "freebsd" {
 		runCC(t, "-pthread", "-o", cmd, cfile, "-ldl")
 	} else {
 		runCC(t, "-pthread", "-o", cmd, cfile)
 	}
 	adbPush(t, cmd)

 	bin := cmdToRun(cmd)

 	defer os.Remove(libname)
 	defer os.Remove(bin)
 	defer os.Remove(pkgname + ".h")

 	out := runExe(t, nil, bin, "./"+libname)
 	if strings.TrimSpace(out) != "PASS" {
 		t.Error(run(t, nil, bin, libname, "verbose"))
 	}
 }

 // test4: test signal handlers
 func TestSignalHandlers(t *testing.T) {
 	t.Parallel()
 	if GOOS == "windows" {
 		t.Logf("Skipping on %s", GOOS)
 		return
 	}
 	testSignalHandlers(t, "libgo4", "main4.c", "testp4")
 }

 // test5: test signal handlers with os/signal.Notify
 func TestSignalHandlersWithNotify(t *testing.T) {
 	t.Parallel()
 	if GOOS == "windows" {
 		t.Logf("Skipping on %s", GOOS)
 		return
 	}
 	testSignalHandlers(t, "libgo5", "main5.c", "testp5")
 }

 func TestPIE(t *testing.T) {
 	t.Parallel()

 	switch GOOS {
 	case "linux", "android":
 		break
 	default:
 		t.Logf("Skipping on %s", GOOS)
 		return
 	}

 	createHeadersOnce(t)

 	f, err := elf.Open(libgoname)
 	if err != nil {
 		t.Fatalf("elf.Open failed: %v", err)
 	}
 	defer f.Close()

 	ds := f.SectionByType(elf.SHT_DYNAMIC)
 	if ds == nil {
 		t.Fatalf("no SHT_DYNAMIC section")
 	}
 	d, err := ds.Data()
 	if err != nil {
 		t.Fatalf("can't read SHT_DYNAMIC contents: %v", err)
 	}
 	for len(d) > 0 {
 		var tag elf.DynTag
 		switch f.Class {
 		case elf.ELFCLASS32:
 			tag = elf.DynTag(f.ByteOrder.Uint32(d[:4]))
 			d = d[8:]
 		case elf.ELFCLASS64:
 			tag = elf.DynTag(f.ByteOrder.Uint64(d[:8]))
 			d = d[16:]
 		}
 		if tag == elf.DT_TEXTREL {
 			t.Fatalf("%s has DT_TEXTREL flag", libgoname)
 		}
 	}
 }

 // Test that installing a second time recreates the header files.
 func TestCachedInstall(t *testing.T) {
 	tmpdir, err := ioutil.TempDir("", "cshared")
 	if err != nil {
 		t.Fatal(err)
 	}
 	// defer os.RemoveAll(tmpdir)

 	copyFile(t, filepath.Join(tmpdir, "src", "libgo", "libgo.go"), filepath.Join("src", "libgo", "libgo.go"))
 	copyFile(t, filepath.Join(tmpdir, "src", "p", "p.go"), filepath.Join("src", "p", "p.go"))

 	env := append(os.Environ(), "GOPATH="+tmpdir)

 	buildcmd := []string{"go", "install", "-x", "-i", "-buildmode=c-shared", "-installsuffix", "testcshared", "libgo"}

 	cmd := exec.Command(buildcmd[0], buildcmd[1:]...)
 	cmd.Env = env
 	t.Log(buildcmd)
 	out, err := cmd.CombinedOutput()
 	t.Logf("%s", out)
 	if err != nil {
 		t.Fatal(err)
 	}

 	var libgoh, ph string

 	walker := func(path string, info os.FileInfo, err error) error {
 		if err != nil {
 			t.Fatal(err)
 		}
 		var ps *string
 		switch filepath.Base(path) {
 		case "libgo.h":
 			ps = &libgoh
 		case "p.h":
 			ps = &ph
 		}
 		if ps != nil {
 			if *ps != "" {
 				t.Fatalf("%s found again", *ps)
 			}
 			*ps = path
 		}
 		return nil
 	}

 	if err := filepath.Walk(tmpdir, walker); err != nil {
 		t.Fatal(err)
 	}

 	if libgoh == "" {
 		t.Fatal("libgo.h not installed")
 	}
 	if ph == "" {
 		t.Fatal("p.h not installed")
 	}

 	if err := os.Remove(libgoh); err != nil {
 		t.Fatal(err)
 	}
 	if err := os.Remove(ph); err != nil {
 		t.Fatal(err)
 	}

 	cmd = exec.Command(buildcmd[0], buildcmd[1:]...)
 	cmd.Env = env
 	t.Log(buildcmd)
 	out, err = cmd.CombinedOutput()
 	t.Logf("%s", out)
 	if err != nil {
 		t.Fatal(err)
 	}

 	if _, err := os.Stat(libgoh); err != nil {
 		t.Errorf("libgo.h not installed in second run: %v", err)
 	}
 	if _, err := os.Stat(ph); err != nil {
 		t.Errorf("p.h not installed in second run: %v", err)
 	}
 }

 // copyFile copies src to dst.
 func copyFile(t *testing.T, dst, src string) {
 	t.Helper()
 	data, err := ioutil.ReadFile(src)
 	if err != nil {
 		t.Fatal(err)
 	}
 	if err := os.MkdirAll(filepath.Dir(dst), 0777); err != nil {
 		t.Fatal(err)
 	}
 	if err := ioutil.WriteFile(dst, data, 0666); err != nil {
 		t.Fatal(err)
 	}
 }

 func TestGo2C2Go(t *testing.T) {
 	switch GOOS {
 	case "darwin":
 		// Darwin shared libraries don't support the multiple
 		// copies of the runtime package implied by this test.
 		t.Skip("linking c-shared into Go programs not supported on Darwin; issue 29061")
 	case "android":
 		t.Skip("test fails on android; issue 29087")
 	}

 	t.Parallel()

 	tmpdir, err := ioutil.TempDir("", "cshared-TestGo2C2Go")
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer os.RemoveAll(tmpdir)

 	shlib := filepath.Join(tmpdir, "libtestgo2c2go."+libSuffix)
 	run(t, gopathEnv, "go", "build", "-buildmode=c-shared", "-o", shlib, "go2c2go/go")

 	cgoCflags := os.Getenv("CGO_CFLAGS")
 	if cgoCflags != "" {
 		cgoCflags += " "
 	}
 	cgoCflags += "-I" + tmpdir

 	cgoLdflags := os.Getenv("CGO_LDFLAGS")
 	if cgoLdflags != "" {
 		cgoLdflags += " "
 	}
 	cgoLdflags += "-L" + tmpdir + " -ltestgo2c2go"

 	goenv := append(gopathEnv[:len(gopathEnv):len(gopathEnv)], "CGO_CFLAGS="+cgoCflags, "CGO_LDFLAGS="+cgoLdflags)

 	ldLibPath := os.Getenv("LD_LIBRARY_PATH")
 	if ldLibPath != "" {
 		ldLibPath += ":"
 	}
 	ldLibPath += tmpdir

 	runenv := append(gopathEnv[:len(gopathEnv):len(gopathEnv)], "LD_LIBRARY_PATH="+ldLibPath)

 	bin := filepath.Join(tmpdir, "m1") + exeSuffix
 	run(t, goenv, "go", "build", "-o", bin, "go2c2go/m1")
 	runExe(t, runenv, bin)

 	bin = filepath.Join(tmpdir, "m2") + exeSuffix
 	run(t, goenv, "go", "build", "-o", bin, "go2c2go/m2")
 	runExe(t, runenv, bin)
 }
	// Copyright 2017 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.

	package cshared_test

	import (
	"debug/elf"
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"os/exec"
	"path"
	"path/filepath"
	"strings"
	"sync"
	"testing"
	"unicode"
	)

	// C compiler with args (from $(go env CC) $(go env GOGCCFLAGS)).
	var cc []string

	// An environment with GOPATH=$(pwd).
	var gopathEnv []string

	// ".exe" on Windows.
	var exeSuffix string

	var GOOS, GOARCH, GOROOT string
	var installdir, androiddir string
	var libSuffix, libgoname string

	func TestMain(m *testing.M) {
	GOOS = goEnv("GOOS")
	GOARCH = goEnv("GOARCH")
	GOROOT = goEnv("GOROOT")

	if _, err := os.Stat(GOROOT); os.IsNotExist(err) {
	log.Fatalf("Unable able to find GOROOT at '%s'", GOROOT)
	}

	// Directory where cgo headers and outputs will be installed.
	// The installation directory format varies depending on the platform.
	installdir = path.Join("pkg", fmt.Sprintf("%s_%s_testcshared", GOOS, GOARCH))
	switch GOOS {
	case "darwin":
	libSuffix = "dylib"
	case "windows":
	libSuffix = "dll"
	default:
	libSuffix = "so"
	installdir = path.Join("pkg", fmt.Sprintf("%s_%s_testcshared_shared", GOOS, GOARCH))
	}

	androiddir = fmt.Sprintf("/data/local/tmp/testcshared-%d", os.Getpid())
	if GOOS == "android" {
	args := append(adbCmd(), "shell", "mkdir", "-p", androiddir)
	cmd := exec.Command(args[0], args[1:]...)
	out, err := cmd.CombinedOutput()
	if err != nil {
	log.Fatalf("setupAndroid failed: %v\n%s\n", err, out)
	}
	}

	libgoname = "libgo." + libSuffix

	cc = []string{goEnv("CC")}

	out := goEnv("GOGCCFLAGS")
	quote := '\000'
	start := 0
	lastSpace := true
	backslash := false
	s := string(out)
	for i, c := range s {
	if quote == '\000' && unicode.IsSpace(c) {
	if !lastSpace {
	cc = append(cc, s[start:i])
	lastSpace = true
	}
	} else {
	if lastSpace {
	start = i
	lastSpace = false
	}
	if quote == '\000' && !backslash && (c == '"' \|\| c == '\'') {
	quote = c
	backslash = false
	} else if !backslash && quote == c {
	quote = '\000'
	} else if (quote == '\000' \|\| quote == '"') && !backslash && c == '\\' {
	backslash = true
	} else {
	backslash = false
	}
	}
	}
	if !lastSpace {
	cc = append(cc, s[start:])
	}

	switch GOOS {
	case "darwin":
	// For Darwin/ARM.
	// TODO(crawshaw): can we do better?
	cc = append(cc, []string{"-framework", "CoreFoundation", "-framework", "Foundation"}...)
	case "android":
	cc = append(cc, "-pie", "-fuse-ld=gold")
	}
	libgodir := GOOS + "_" + GOARCH
	switch GOOS {
	case "darwin":
	if GOARCH == "arm" \|\| GOARCH == "arm64" {
	libgodir += "_shared"
	}
	case "dragonfly", "freebsd", "linux", "netbsd", "openbsd", "solaris":
	libgodir += "_shared"
	}
	cc = append(cc, "-I", filepath.Join("pkg", libgodir))

	// Build an environment with GOPATH=$(pwd)
	dir, err := os.Getwd()
	if err != nil {
	fmt.Fprintln(os.Stderr, err)
	os.Exit(2)
	}
	gopathEnv = append(os.Environ(), "GOPATH="+dir)

	if GOOS == "windows" {
	exeSuffix = ".exe"
	}

	st := m.Run()

	os.Remove(libgoname)
	os.RemoveAll("pkg")
	cleanupHeaders()
	cleanupAndroid()

	os.Exit(st)
	}

	func goEnv(key string) string {
	out, err := exec.Command("go", "env", key).Output()
	if err != nil {
	fmt.Fprintf(os.Stderr, "go env %s failed:\n%s", key, err)
	fmt.Fprintf(os.Stderr, "%s", err.(*exec.ExitError).Stderr)
	os.Exit(2)
	}
	return strings.TrimSpace(string(out))
	}

	func cmdToRun(name string) string {
	return "./" + name + exeSuffix
	}

	func adbCmd() []string {
	cmd := []string{"adb"}
	if flags := os.Getenv("GOANDROID_ADB_FLAGS"); flags != "" {
	cmd = append(cmd, strings.Split(flags, " ")...)
	}
	return cmd
	}

	func adbPush(t *testing.T, filename string) {
	if GOOS != "android" {
	return
	}
	args := append(adbCmd(), "push", filename, fmt.Sprintf("%s/%s", androiddir, filename))
	cmd := exec.Command(args[0], args[1:]...)
	if out, err := cmd.CombinedOutput(); err != nil {
	t.Fatalf("adb command failed: %v\n%s\n", err, out)
	}
	}

	func adbRun(t *testing.T, env []string, adbargs ...string) string {
	if GOOS != "android" {
	t.Fatalf("trying to run adb command when operating system is not android.")
	}
	args := append(adbCmd(), "shell")
	// Propagate LD_LIBRARY_PATH to the adb shell invocation.
	for _, e := range env {
	if strings.Index(e, "LD_LIBRARY_PATH=") != -1 {
	adbargs = append([]string{e}, adbargs...)
	break
	}
	}
	shellcmd := fmt.Sprintf("cd %s; %s", androiddir, strings.Join(adbargs, " "))
	args = append(args, shellcmd)
	cmd := exec.Command(args[0], args[1:]...)
	out, err := cmd.CombinedOutput()
	if err != nil {
	t.Fatalf("adb command failed: %v\n%s\n", err, out)
	}
	return strings.Replace(string(out), "\r", "", -1)
	}

	func run(t *testing.T, env []string, args ...string) string {
	t.Helper()
	cmd := exec.Command(args[0], args[1:]...)
	cmd.Env = env

	if GOOS != "windows" {
	// TestUnexportedSymbols relies on file descriptor 30
	// being closed when the program starts, so enforce
	// that in all cases. (The first three descriptors are
	// stdin/stdout/stderr, so we just need to make sure
	// that cmd.ExtraFiles[27] exists and is nil.)
	cmd.ExtraFiles = make([]*os.File, 28)
	}

	out, err := cmd.CombinedOutput()
	if err != nil {
	t.Fatalf("command failed: %v\n%v\n%s\n", args, err, out)
	} else {
	t.Logf("run: %v", args)
	}
	return string(out)
	}

	func runExe(t *testing.T, env []string, args ...string) string {
	t.Helper()
	if GOOS == "android" {
	return adbRun(t, env, args...)
	}
	return run(t, env, args...)
	}

	func runCC(t *testing.T, args ...string) string {
	t.Helper()
	// This function is run in parallel, so append to a copy of cc
	// rather than cc itself.
	return run(t, nil, append(append([]string(nil), cc...), args...)...)
	}

	func createHeaders() error {
	args := []string{"go", "install", "-i", "-buildmode=c-shared",
	"-installsuffix", "testcshared", "libgo"}
	cmd := exec.Command(args[0], args[1:]...)
	cmd.Env = gopathEnv
	out, err := cmd.CombinedOutput()
	if err != nil {
	return fmt.Errorf("command failed: %v\n%v\n%s\n", args, err, out)
	}

	args = []string{"go", "build", "-buildmode=c-shared",
	"-installsuffix", "testcshared",
	"-o", libgoname,
	filepath.Join("src", "libgo", "libgo.go")}
	cmd = exec.Command(args[0], args[1:]...)
	cmd.Env = gopathEnv
	out, err = cmd.CombinedOutput()
	if err != nil {
	return fmt.Errorf("command failed: %v\n%v\n%s\n", args, err, out)
	}

	if GOOS == "android" {
	args = append(adbCmd(), "push", libgoname, fmt.Sprintf("%s/%s", androiddir, libgoname))
	cmd = exec.Command(args[0], args[1:]...)
	out, err = cmd.CombinedOutput()
	if err != nil {
	return fmt.Errorf("adb command failed: %v\n%s\n", err, out)
	}
	}

	return nil
	}

	var (
	headersOnce sync.Once
	headersErr error
	)

	func createHeadersOnce(t *testing.T) {
	headersOnce.Do(func() {
	headersErr = createHeaders()
	})
	if headersErr != nil {
	t.Fatal(headersErr)
	}
	}

	func cleanupHeaders() {
	os.Remove("libgo.h")
	}

	func cleanupAndroid() {
	if GOOS != "android" {
	return
	}
	args := append(adbCmd(), "shell", "rm", "-rf", androiddir)
	cmd := exec.Command(args[0], args[1:]...)
	out, err := cmd.CombinedOutput()
	if err != nil {
	log.Fatalf("cleanupAndroid failed: %v\n%s\n", err, out)
	}
	}

	// test0: exported symbols in shared lib are accessible.
	func TestExportedSymbols(t *testing.T) {
	t.Parallel()

	cmd := "testp0"
	bin := cmdToRun(cmd)

	createHeadersOnce(t)

	runCC(t, "-I", installdir, "-o", cmd, "main0.c", libgoname)
	adbPush(t, cmd)

	defer os.Remove(bin)

	out := runExe(t, append(gopathEnv, "LD_LIBRARY_PATH=."), bin)
	if strings.TrimSpace(out) != "PASS" {
	t.Error(out)
	}
	}

	// test1: shared library can be dynamically loaded and exported symbols are accessible.
	func TestExportedSymbolsWithDynamicLoad(t *testing.T) {
	t.Parallel()

	if GOOS == "windows" {
	t.Logf("Skipping on %s", GOOS)
	return
	}

	cmd := "testp1"
	bin := cmdToRun(cmd)

	createHeadersOnce(t)

	if GOOS != "freebsd" {
	runCC(t, "-o", cmd, "main1.c", "-ldl")
	} else {
	runCC(t, "-o", cmd, "main1.c")
	}
	adbPush(t, cmd)

	defer os.Remove(bin)

	out := runExe(t, nil, bin, "./"+libgoname)
	if strings.TrimSpace(out) != "PASS" {
	t.Error(out)
	}
	}

	// test2: tests libgo2 which does not export any functions.
	func TestUnexportedSymbols(t *testing.T) {
	t.Parallel()

	if GOOS == "windows" {
	t.Logf("Skipping on %s", GOOS)
	return
	}

	cmd := "testp2"
	bin := cmdToRun(cmd)
	libname := "libgo2." + libSuffix

	run(t,
	gopathEnv,
	"go", "build",
	"-buildmode=c-shared",
	"-installsuffix", "testcshared",
	"-o", libname, "libgo2",
	)
	adbPush(t, libname)

	linkFlags := "-Wl,--no-as-needed"
	if GOOS == "darwin" {
	linkFlags = ""
	}

	runCC(t, "-o", cmd, "main2.c", linkFlags, libname)
	adbPush(t, cmd)

	defer os.Remove(libname)
	defer os.Remove(bin)

	out := runExe(t, append(gopathEnv, "LD_LIBRARY_PATH=."), bin)

	if strings.TrimSpace(out) != "PASS" {
	t.Error(out)
	}
	}

	// test3: tests main.main is exported on android.
	func TestMainExportedOnAndroid(t *testing.T) {
	t.Parallel()

	switch GOOS {
	case "android":
	break
	default:
	t.Logf("Skipping on %s", GOOS)
	return
	}

	cmd := "testp3"
	bin := cmdToRun(cmd)

	createHeadersOnce(t)

	runCC(t, "-o", cmd, "main3.c", "-ldl")
	adbPush(t, cmd)

	defer os.Remove(bin)

	out := runExe(t, nil, bin, "./"+libgoname)
	if strings.TrimSpace(out) != "PASS" {
	t.Error(out)
	}
	}

	func testSignalHandlers(t *testing.T, pkgname, cfile, cmd string) {
	libname := pkgname + "." + libSuffix
	run(t,
	gopathEnv,
	"go", "build",
	"-buildmode=c-shared",
	"-installsuffix", "testcshared",
	"-o", libname, pkgname,
	)
	adbPush(t, libname)
	if GOOS != "freebsd" {
	runCC(t, "-pthread", "-o", cmd, cfile, "-ldl")
	} else {
	runCC(t, "-pthread", "-o", cmd, cfile)
	}
	adbPush(t, cmd)

	bin := cmdToRun(cmd)

	defer os.Remove(libname)
	defer os.Remove(bin)
	defer os.Remove(pkgname + ".h")

	out := runExe(t, nil, bin, "./"+libname)
	if strings.TrimSpace(out) != "PASS" {
	t.Error(run(t, nil, bin, libname, "verbose"))
	}
	}

	// test4: test signal handlers
	func TestSignalHandlers(t *testing.T) {
	t.Parallel()
	if GOOS == "windows" {
	t.Logf("Skipping on %s", GOOS)
	return
	}
	testSignalHandlers(t, "libgo4", "main4.c", "testp4")
	}

	// test5: test signal handlers with os/signal.Notify
	func TestSignalHandlersWithNotify(t *testing.T) {
	t.Parallel()
	if GOOS == "windows" {
	t.Logf("Skipping on %s", GOOS)
	return
	}
	testSignalHandlers(t, "libgo5", "main5.c", "testp5")
	}

	func TestPIE(t *testing.T) {
	t.Parallel()

	switch GOOS {
	case "linux", "android":
	break
	default:
	t.Logf("Skipping on %s", GOOS)
	return
	}

	createHeadersOnce(t)

	f, err := elf.Open(libgoname)
	if err != nil {
	t.Fatalf("elf.Open failed: %v", err)
	}
	defer f.Close()

	ds := f.SectionByType(elf.SHT_DYNAMIC)
	if ds == nil {
	t.Fatalf("no SHT_DYNAMIC section")
	}
	d, err := ds.Data()
	if err != nil {
	t.Fatalf("can't read SHT_DYNAMIC contents: %v", err)
	}
	for len(d) > 0 {
	var tag elf.DynTag
	switch f.Class {
	case elf.ELFCLASS32:
	tag = elf.DynTag(f.ByteOrder.Uint32(d[:4]))
	d = d[8:]
	case elf.ELFCLASS64:
	tag = elf.DynTag(f.ByteOrder.Uint64(d[:8]))
	d = d[16:]
	}
	if tag == elf.DT_TEXTREL {
	t.Fatalf("%s has DT_TEXTREL flag", libgoname)
	}
	}
	}

	// Test that installing a second time recreates the header files.
	func TestCachedInstall(t *testing.T) {
	tmpdir, err := ioutil.TempDir("", "cshared")
	if err != nil {
	t.Fatal(err)
	}
	// defer os.RemoveAll(tmpdir)

	copyFile(t, filepath.Join(tmpdir, "src", "libgo", "libgo.go"), filepath.Join("src", "libgo", "libgo.go"))
	copyFile(t, filepath.Join(tmpdir, "src", "p", "p.go"), filepath.Join("src", "p", "p.go"))

	env := append(os.Environ(), "GOPATH="+tmpdir)

	buildcmd := []string{"go", "install", "-x", "-i", "-buildmode=c-shared", "-installsuffix", "testcshared", "libgo"}

	cmd := exec.Command(buildcmd[0], buildcmd[1:]...)
	cmd.Env = env
	t.Log(buildcmd)
	out, err := cmd.CombinedOutput()
	t.Logf("%s", out)
	if err != nil {
	t.Fatal(err)
	}

	var libgoh, ph string

	walker := func(path string, info os.FileInfo, err error) error {
	if err != nil {
	t.Fatal(err)
	}
	var ps *string
	switch filepath.Base(path) {
	case "libgo.h":
	ps = &libgoh
	case "p.h":
	ps = &ph
	}
	if ps != nil {
	if *ps != "" {
	t.Fatalf("%s found again", *ps)
	}
	*ps = path
	}
	return nil
	}

	if err := filepath.Walk(tmpdir, walker); err != nil {
	t.Fatal(err)
	}

	if libgoh == "" {
	t.Fatal("libgo.h not installed")
	}
	if ph == "" {
	t.Fatal("p.h not installed")
	}

	if err := os.Remove(libgoh); err != nil {
	t.Fatal(err)
	}
	if err := os.Remove(ph); err != nil {
	t.Fatal(err)
	}

	cmd = exec.Command(buildcmd[0], buildcmd[1:]...)
	cmd.Env = env
	t.Log(buildcmd)
	out, err = cmd.CombinedOutput()
	t.Logf("%s", out)
	if err != nil {
	t.Fatal(err)
	}

	if _, err := os.Stat(libgoh); err != nil {
	t.Errorf("libgo.h not installed in second run: %v", err)
	}
	if _, err := os.Stat(ph); err != nil {
	t.Errorf("p.h not installed in second run: %v", err)
	}
	}

	// copyFile copies src to dst.
	func copyFile(t *testing.T, dst, src string) {
	t.Helper()
	data, err := ioutil.ReadFile(src)
	if err != nil {
	t.Fatal(err)
	}
	if err := os.MkdirAll(filepath.Dir(dst), 0777); err != nil {
	t.Fatal(err)
	}
	if err := ioutil.WriteFile(dst, data, 0666); err != nil {
	t.Fatal(err)
	}
	}

	func TestGo2C2Go(t *testing.T) {
	switch GOOS {
	case "darwin":
	// Darwin shared libraries don't support the multiple
	// copies of the runtime package implied by this test.
	t.Skip("linking c-shared into Go programs not supported on Darwin; issue 29061")
	case "android":
	t.Skip("test fails on android; issue 29087")
	}

	t.Parallel()

	tmpdir, err := ioutil.TempDir("", "cshared-TestGo2C2Go")
	if err != nil {
	t.Fatal(err)
	}
	defer os.RemoveAll(tmpdir)

	shlib := filepath.Join(tmpdir, "libtestgo2c2go."+libSuffix)
	run(t, gopathEnv, "go", "build", "-buildmode=c-shared", "-o", shlib, "go2c2go/go")

	cgoCflags := os.Getenv("CGO_CFLAGS")
	if cgoCflags != "" {
	cgoCflags += " "
	}
	cgoCflags += "-I" + tmpdir

	cgoLdflags := os.Getenv("CGO_LDFLAGS")
	if cgoLdflags != "" {
	cgoLdflags += " "
	}
	cgoLdflags += "-L" + tmpdir + " -ltestgo2c2go"

	goenv := append(gopathEnv[:len(gopathEnv):len(gopathEnv)], "CGO_CFLAGS="+cgoCflags, "CGO_LDFLAGS="+cgoLdflags)

	ldLibPath := os.Getenv("LD_LIBRARY_PATH")
	if ldLibPath != "" {
	ldLibPath += ":"
	}
	ldLibPath += tmpdir

	runenv := append(gopathEnv[:len(gopathEnv):len(gopathEnv)], "LD_LIBRARY_PATH="+ldLibPath)

	bin := filepath.Join(tmpdir, "m1") + exeSuffix
	run(t, goenv, "go", "build", "-o", bin, "go2c2go/m1")
	runExe(t, runenv, bin)

	bin = filepath.Join(tmpdir, "m2") + exeSuffix
	run(t, goenv, "go", "build", "-o", bin, "go2c2go/m2")
	runExe(t, runenv, bin)
	}