1 files changed, 483 insertions, 0 deletions
diff --git a/runsc/testutil/testutil.go b/runsc/testutil/testutil.go
new file mode 100644
index 000000000..edf8b126c
--- /dev/null
+++ b/runsc/testutil/testutil.go
@@ -0,0 +1,483 @@
+// 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"
+	"math/rand"
+	"net/http"
+	"os"
+	"os/exec"
+	"os/signal"
+	"path/filepath"
+	"strconv"
+	"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
+}
+
+// TestBoundsForShard calculates the beginning and end indices for the test
+// based on the TEST_SHARD_INDEX and TEST_TOTAL_SHARDS environment vars. The
+// returned ints are the beginning (inclusive) and end (exclusive) of the
+// subslice corresponding to the shard. If either of the env vars are not
+// present, then the function will return bounds that include all tests. If
+// there are more shards than there are tests, then the returned list may be
+// empty.
+func TestBoundsForShard(numTests int) (int, int, error) {
+	var (
+		begin = 0
+		end   = numTests
+	)
+	indexStr, totalStr := os.Getenv("TEST_SHARD_INDEX"), os.Getenv("TEST_TOTAL_SHARDS")
+	if indexStr == "" || totalStr == "" {
+		return begin, end, nil
+	}
+
+	// Parse index and total to ints.
+	shardIndex, err := strconv.Atoi(indexStr)
+	if err != nil {
+		return 0, 0, fmt.Errorf("invalid TEST_SHARD_INDEX %q: %v", indexStr, err)
+	}
+	shardTotal, err := strconv.Atoi(totalStr)
+	if err != nil {
+		return 0, 0, fmt.Errorf("invalid TEST_TOTAL_SHARDS %q: %v", totalStr, err)
+	}
+
+	// Calculate!
+	shardSize := int(math.Ceil(float64(numTests) / float64(shardTotal)))
+	begin = shardIndex * shardSize
+	end = ((shardIndex + 1) * shardSize)
+	if begin > numTests {
+		// Nothing to run.
+		return 0, 0, nil
+	}
+	if end > numTests {
+		end = numTests
+	}
+	return begin, end, nil
+}