Impose order on test scripts.

The simple test script has gotten out of control. Shard this script into
different pieces and attempt to impose order on overall test structure. This
change helps lay some of the foundations for future improvements.

 * The runsc/test directories are moved into just test/.
 * The runsc/test/testutil package is split into logical pieces.
 * The scripts/ directory contains new top-level targets.
 * Each test is now responsible for building targets it requires.
 * The install functionality is moved into `runsc` itself for simplicity.
 * The existing kokoro run_tests.sh file now just calls all (can be split).

After this change is merged,  I will create multiple distinct workflows for
Kokoro, one for each of the scripts currently targeted by `run_tests.sh` today,
which should dramatically reduce the time-to-run for the Kokoro tests, and
provides a better foundation for further improvements to the infrastructure.

PiperOrigin-RevId: 267081397

2 files changed, 457 insertions, 0 deletions

diff --git a/runsc/testutil/BUILD b/runsc/testutil/BUILD
new file mode 100644
index 000000000..d44ebc906
--- /dev/null
+++ b/runsc/testutil/BUILD
@@ -0,0 +1,17 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+package(licenses = ["notice"])
+
+go_library(
+    name = "testutil",
+    testonly = 1,
+    srcs = ["testutil.go"],
+    importpath = "gvisor.dev/gvisor/runsc/testutil",
+    visibility = ["//:sandbox"],
+    deps = [
+        "//runsc/boot",
+        "//runsc/specutils",
+        "@com_github_cenkalti_backoff//:go_default_library",
+        "@com_github_opencontainers_runtime-spec//specs-go:go_default_library",
+    ],
+)
diff --git a/runsc/testutil/testutil.go b/runsc/testutil/testutil.go
new file mode 100644
index 000000000..57ab73d97
--- /dev/null
+++ b/runsc/testutil/testutil.go
@@ -0,0 +1,440 @@
+// Copyright 2018 The gVisor 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 testutil contains utility functions for runsc tests.
+package testutil
+
+import (
+	"bufio"
+	"context"
+	"debug/elf"
+	"encoding/base32"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"math/rand"
+	"net/http"
+	"os"
+	"os/exec"
+	"os/signal"
+	"path/filepath"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"syscall"
+	"time"
+
+	"github.com/cenkalti/backoff"
+	specs "github.com/opencontainers/runtime-spec/specs-go"
+	"gvisor.dev/gvisor/runsc/boot"
+	"gvisor.dev/gvisor/runsc/specutils"
+)
+
+var (
+	checkpoint = flag.Bool("checkpoint", true, "control checkpoint/restore support")
+)
+
+func init() {
+	rand.Seed(time.Now().UnixNano())
+}
+
+// IsCheckpointSupported returns the relevant command line flag.
+func IsCheckpointSupported() bool {
+	return *checkpoint
+}
+
+// TmpDir returns the absolute path to a writable directory that can be used as
+// scratch by the test.
+func TmpDir() string {
+	dir := os.Getenv("TEST_TMPDIR")
+	if dir == "" {
+		dir = "/tmp"
+	}
+	return dir
+}
+
+// ConfigureExePath configures the executable for runsc in the test environment.
+func ConfigureExePath() error {
+	path, err := FindFile("runsc/runsc")
+	if err != nil {
+		return err
+	}
+	specutils.ExePath = path
+	return nil
+}
+
+// FindFile searchs for a file inside the test run environment. It returns the
+// full path to the file. It fails if none or more than one file is found.
+func FindFile(path string) (string, error) {
+	wd, err := os.Getwd()
+	if err != nil {
+		return "", err
+	}
+
+	// The test root is demarcated by a path element called "__main__". Search for
+	// it backwards from the working directory.
+	root := wd
+	for {
+		dir, name := filepath.Split(root)
+		if name == "__main__" {
+			break
+		}
+		if len(dir) == 0 {
+			return "", fmt.Errorf("directory __main__ not found in %q", wd)
+		}
+		// Remove ending slash to loop around.
+		root = dir[:len(dir)-1]
+	}
+
+	// Annoyingly, bazel adds the build type to the directory path for go
+	// binaries, but not for c++ binaries. We use two different patterns to
+	// to find our file.
+	patterns := []string{
+		// Try the obvious path first.
+		filepath.Join(root, path),
+		// If it was a go binary, use a wildcard to match the build
+		// type. The pattern is: /test-path/__main__/directories/*/file.
+		filepath.Join(root, filepath.Dir(path), "*", filepath.Base(path)),
+	}
+
+	for _, p := range patterns {
+		matches, err := filepath.Glob(p)
+		if err != nil {
+			// "The only possible returned error is ErrBadPattern,
+			// when pattern is malformed." -godoc
+			return "", fmt.Errorf("error globbing %q: %v", p, err)
+		}
+		switch len(matches) {
+		case 0:
+			// Try the next pattern.
+		case 1:
+			// We found it.
+			return matches[0], nil
+		default:
+			return "", fmt.Errorf("more than one match found for %q: %s", path, matches)
+		}
+	}
+	return "", fmt.Errorf("file %q not found", path)
+}
+
+// TestConfig returns the default configuration to use in tests. Note that
+// 'RootDir' must be set by caller if required.
+func TestConfig() *boot.Config {
+	return &boot.Config{
+		Debug:           true,
+		LogFormat:       "text",
+		DebugLogFormat:  "text",
+		AlsoLogToStderr: true,
+		LogPackets:      true,
+		Network:         boot.NetworkNone,
+		Strace:          true,
+		Platform:        "ptrace",
+		FileAccess:      boot.FileAccessExclusive,
+		TestOnlyAllowRunAsCurrentUserWithoutChroot: true,
+		NumNetworkChannels:                         1,
+	}
+}
+
+// TestConfigWithRoot returns the default configuration to use in tests.
+func TestConfigWithRoot(rootDir string) *boot.Config {
+	conf := TestConfig()
+	conf.RootDir = rootDir
+	return conf
+}
+
+// NewSpecWithArgs creates a simple spec with the given args suitable for use
+// in tests.
+func NewSpecWithArgs(args ...string) *specs.Spec {
+	return &specs.Spec{
+		// The host filesystem root is the container root.
+		Root: &specs.Root{
+			Path:     "/",
+			Readonly: true,
+		},
+		Process: &specs.Process{
+			Args: args,
+			Env: []string{
+				"PATH=" + os.Getenv("PATH"),
+			},
+			Capabilities: specutils.AllCapabilities(),
+		},
+		Mounts: []specs.Mount{
+			// Root is readonly, but many tests want to write to tmpdir.
+			// This creates a writable mount inside the root. Also, when tmpdir points
+			// to "/tmp", it makes the the actual /tmp to be mounted and not a tmpfs
+			// inside the sentry.
+			{
+				Type:        "bind",
+				Destination: TmpDir(),
+				Source:      TmpDir(),
+			},
+		},
+		Hostname: "runsc-test-hostname",
+	}
+}
+
+// SetupRootDir creates a root directory for containers.
+func SetupRootDir() (string, error) {
+	rootDir, err := ioutil.TempDir(TmpDir(), "containers")
+	if err != nil {
+		return "", fmt.Errorf("error creating root dir: %v", err)
+	}
+	return rootDir, nil
+}
+
+// SetupContainer creates a bundle and root dir for the container, generates a
+// test config, and writes the spec to config.json in the bundle dir.
+func SetupContainer(spec *specs.Spec, conf *boot.Config) (rootDir, bundleDir string, err error) {
+	rootDir, err = SetupRootDir()
+	if err != nil {
+		return "", "", err
+	}
+	conf.RootDir = rootDir
+	bundleDir, err = SetupBundleDir(spec)
+	return rootDir, bundleDir, err
+}
+
+// SetupBundleDir creates a bundle dir and writes the spec to config.json.
+func SetupBundleDir(spec *specs.Spec) (bundleDir string, err error) {
+	bundleDir, err = ioutil.TempDir(TmpDir(), "bundle")
+	if err != nil {
+		return "", fmt.Errorf("error creating bundle dir: %v", err)
+	}
+
+	if err = writeSpec(bundleDir, spec); err != nil {
+		return "", fmt.Errorf("error writing spec: %v", err)
+	}
+	return bundleDir, nil
+}
+
+// writeSpec writes the spec to disk in the given directory.
+func writeSpec(dir string, spec *specs.Spec) error {
+	b, err := json.Marshal(spec)
+	if err != nil {
+		return err
+	}
+	return ioutil.WriteFile(filepath.Join(dir, "config.json"), b, 0755)
+}
+
+// UniqueContainerID generates a unique container id for each test.
+//
+// The container id is used to create an abstract unix domain socket, which must
+// be unique.  While the container forbids creating two containers with the same
+// name, sometimes between test runs the socket does not get cleaned up quickly
+// enough, causing container creation to fail.
+func UniqueContainerID() string {
+	// Read 20 random bytes.
+	b := make([]byte, 20)
+	// "[Read] always returns len(p) and a nil error." --godoc
+	if _, err := rand.Read(b); err != nil {
+		panic("rand.Read failed: " + err.Error())
+	}
+	// base32 encode the random bytes, so that the name is a valid
+	// container id and can be used as a socket name in the filesystem.
+	return fmt.Sprintf("test-container-%s", base32.StdEncoding.EncodeToString(b))
+}
+
+// Copy copies file from src to dst.
+func Copy(src, dst string) error {
+	in, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer in.Close()
+
+	out, err := os.Create(dst)
+	if err != nil {
+		return err
+	}
+	defer out.Close()
+
+	_, err = io.Copy(out, in)
+	return err
+}
+
+// Poll is a shorthand function to poll for something with given timeout.
+func Poll(cb func() error, timeout time.Duration) error {
+	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	defer cancel()
+	b := backoff.WithContext(backoff.NewConstantBackOff(100*time.Millisecond), ctx)
+	return backoff.Retry(cb, b)
+}
+
+// WaitForHTTP tries GET requests on a port until the call succeeds or timeout.
+func WaitForHTTP(port int, timeout time.Duration) error {
+	cb := func() error {
+		c := &http.Client{
+			// Calculate timeout to be able to do minimum 5 attempts.
+			Timeout: timeout / 5,
+		}
+		url := fmt.Sprintf("http://localhost:%d/", port)
+		resp, err := c.Get(url)
+		if err != nil {
+			log.Printf("Waiting %s: %v", url, err)
+			return err
+		}
+		resp.Body.Close()
+		return nil
+	}
+	return Poll(cb, timeout)
+}
+
+// Reaper reaps child processes.
+type Reaper struct {
+	// mu protects ch, which will be nil if the reaper is not running.
+	mu sync.Mutex
+	ch chan os.Signal
+}
+
+// Start starts reaping child processes.
+func (r *Reaper) Start() {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
+	if r.ch != nil {
+		panic("reaper.Start called on a running reaper")
+	}
+
+	r.ch = make(chan os.Signal, 1)
+	signal.Notify(r.ch, syscall.SIGCHLD)
+
+	go func() {
+		for {
+			r.mu.Lock()
+			ch := r.ch
+			r.mu.Unlock()
+			if ch == nil {
+				return
+			}
+
+			_, ok := <-ch
+			if !ok {
+				// Channel closed.
+				return
+			}
+			for {
+				cpid, _ := syscall.Wait4(-1, nil, syscall.WNOHANG, nil)
+				if cpid < 1 {
+					break
+				}
+			}
+		}
+	}()
+}
+
+// Stop stops reaping child processes.
+func (r *Reaper) Stop() {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
+	if r.ch == nil {
+		panic("reaper.Stop called on a stopped reaper")
+	}
+
+	signal.Stop(r.ch)
+	close(r.ch)
+	r.ch = nil
+}
+
+// StartReaper is a helper that starts a new Reaper and returns a function to
+// stop it.
+func StartReaper() func() {
+	r := &Reaper{}
+	r.Start()
+	return r.Stop
+}
+
+// WaitUntilRead reads from the given reader until the wanted string is found
+// or until timeout.
+func WaitUntilRead(r io.Reader, want string, split bufio.SplitFunc, timeout time.Duration) error {
+	sc := bufio.NewScanner(r)
+	if split != nil {
+		sc.Split(split)
+	}
+	// done must be accessed atomically. A value greater than 0 indicates
+	// that the read loop can exit.
+	var done uint32
+	doneCh := make(chan struct{})
+	go func() {
+		for sc.Scan() {
+			t := sc.Text()
+			if strings.Contains(t, want) {
+				atomic.StoreUint32(&done, 1)
+				close(doneCh)
+				break
+			}
+			if atomic.LoadUint32(&done) > 0 {
+				break
+			}
+		}
+	}()
+	select {
+	case <-time.After(timeout):
+		atomic.StoreUint32(&done, 1)
+		return fmt.Errorf("timeout waiting to read %q", want)
+	case <-doneCh:
+		return nil
+	}
+}
+
+// KillCommand kills the process running cmd unless it hasn't been started. It
+// returns an error if it cannot kill the process unless the reason is that the
+// process has already exited.
+func KillCommand(cmd *exec.Cmd) error {
+	if cmd.Process == nil {
+		return nil
+	}
+	if err := cmd.Process.Kill(); err != nil {
+		if !strings.Contains(err.Error(), "process already finished") {
+			return fmt.Errorf("failed to kill process %v: %v", cmd, err)
+		}
+	}
+	return nil
+}
+
+// WriteTmpFile writes text to a temporary file, closes the file, and returns
+// the name of the file.
+func WriteTmpFile(pattern, text string) (string, error) {
+	file, err := ioutil.TempFile(TmpDir(), pattern)
+	if err != nil {
+		return "", err
+	}
+	defer file.Close()
+	if _, err := file.Write([]byte(text)); err != nil {
+		return "", err
+	}
+	return file.Name(), nil
+}
+
+// RandomName create a name with a 6 digit random number appended to it.
+func RandomName(prefix string) string {
+	return fmt.Sprintf("%s-%06d", prefix, rand.Int31n(1000000))
+}
+
+// IsStatic returns true iff the given file is a static binary.
+func IsStatic(filename string) (bool, error) {
+	f, err := elf.Open(filename)
+	if err != nil {
+		return false, err
+	}
+	for _, prog := range f.Progs {
+		if prog.Type == elf.PT_INTERP {
+			return false, nil // Has interpreter.
+		}
+	}
+	return true, nil
+}