Merge pull request opencontainers#3158 from kolyshkin/nsenter-tests

libct/nsenter/nsenter_test.go: fix and improve

Author: thaJeztah

libcontainer/nsenter/nsenter_test.go

@@ -6,7 +6,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"strings"
@@ -17,21 +16,9 @@ import (
 	"golang.org/x/sys/unix"
 )
 
-type pid struct {
-	Pid int `json:"Pid"`
-}
-
-type logentry struct {
-	Msg   string `json:"msg"`
-	Level string `json:"level"`
-}
-
 func TestNsenterValidPaths(t *testing.T) {
 	args := []string{"nsenter-exec"}
-	parent, child, err := newPipe()
-	if err != nil {
-		t.Fatalf("failed to create pipe %v", err)
-	}
+	parent, child := newPipe(t)
 
 	namespaces := []string{
 		// join pid ns of the current process
@@ -47,8 +34,9 @@ func TestNsenterValidPaths(t *testing.T) {
 	}
 
 	if err := cmd.Start(); err != nil {
-		t.Fatalf("nsenter failed to start %v", err)
+		t.Fatalf("nsenter failed to start: %v", err)
 	}
+	child.Close()
 
 	// write cloneFlags
 	r := nl.NewNetlinkRequest(int(libcontainer.InitMsg), 0)
@@ -66,36 +54,18 @@ func TestNsenterValidPaths(t *testing.T) {
 
 	initWaiter(t, parent)
 
-	decoder := json.NewDecoder(parent)
-	var pid *pid
-
 	if err := cmd.Wait(); err != nil {
-		t.Fatalf("nsenter exits with a non-zero exit status")
-	}
-	if err := decoder.Decode(&pid); err != nil {
-		dir, _ := ioutil.ReadDir(fmt.Sprintf("/proc/%d/ns", os.Getpid()))
-		for _, d := range dir {
-			t.Log(d.Name())
-		}
-		t.Fatalf("%v", err)
+		t.Fatalf("nsenter error: %v", err)
 	}
 
-	p, err := os.FindProcess(pid.Pid)
-	if err != nil {
-		t.Fatalf("%v", err)
-	}
-	_, _ = p.Wait()
+	reapChildren(t, parent)
 }
 
 func TestNsenterInvalidPaths(t *testing.T) {
 	args := []string{"nsenter-exec"}
-	parent, child, err := newPipe()
-	if err != nil {
-		t.Fatalf("failed to create pipe %v", err)
-	}
+	parent, child := newPipe(t)
 
 	namespaces := []string{
-		// join pid ns of the current process
 		fmt.Sprintf("pid:/proc/%d/ns/pid", -1),
 	}
 	cmd := &exec.Cmd{
@@ -106,8 +76,10 @@ func TestNsenterInvalidPaths(t *testing.T) {
 	}
 
 	if err := cmd.Start(); err != nil {
-		t.Fatal(err)
+		t.Fatalf("nsenter failed to start: %v", err)
 	}
+	child.Close()
+
 	// write cloneFlags
 	r := nl.NewNetlinkRequest(int(libcontainer.InitMsg), 0)
 	r.AddData(&libcontainer.Int32msg{
@@ -130,13 +102,9 @@ func TestNsenterInvalidPaths(t *testing.T) {
 
 func TestNsenterIncorrectPathType(t *testing.T) {
 	args := []string{"nsenter-exec"}
-	parent, child, err := newPipe()
-	if err != nil {
-		t.Fatalf("failed to create pipe %v", err)
-	}
+	parent, child := newPipe(t)
 
 	namespaces := []string{
-		// join pid ns of the current process
 		fmt.Sprintf("net:/proc/%d/ns/pid", os.Getpid()),
 	}
 	cmd := &exec.Cmd{
@@ -147,8 +115,10 @@ func TestNsenterIncorrectPathType(t *testing.T) {
 	}
 
 	if err := cmd.Start(); err != nil {
-		t.Fatal(err)
+		t.Fatalf("nsenter failed to start: %v", err)
 	}
+	child.Close()
+
 	// write cloneFlags
 	r := nl.NewNetlinkRequest(int(libcontainer.InitMsg), 0)
 	r.AddData(&libcontainer.Int32msg{
@@ -165,24 +135,14 @@ func TestNsenterIncorrectPathType(t *testing.T) {
 
 	initWaiter(t, parent)
 	if err := cmd.Wait(); err == nil {
-		t.Fatalf("nsenter exits with a zero exit status")
+		t.Fatalf("nsenter error: %v", err)
 	}
 }
 
 func TestNsenterChildLogging(t *testing.T) {
 	args := []string{"nsenter-exec"}
-	parent, child, err := newPipe()
-	if err != nil {
-		t.Fatalf("failed to create exec pipe %v", err)
-	}
-	logread, logwrite, err := os.Pipe()
-	if err != nil {
-		t.Fatalf("failed to create log pipe %v", err)
-	}
-	defer func() {
-		_ = logwrite.Close()
-		_ = logread.Close()
-	}()
+	parent, child := newPipe(t)
+	logread, logwrite := newPipe(t)
 
 	namespaces := []string{
 		// join pid ns of the current process
@@ -198,8 +158,11 @@ func TestNsenterChildLogging(t *testing.T) {
 	}
 
 	if err := cmd.Start(); err != nil {
-		t.Fatalf("nsenter failed to start %v", err)
+		t.Fatalf("nsenter failed to start: %v", err)
 	}
+	child.Close()
+	logwrite.Close()
+
 	// write cloneFlags
 	r := nl.NewNetlinkRequest(int(libcontainer.InitMsg), 0)
 	r.AddData(&libcontainer.Int32msg{
@@ -216,20 +179,12 @@ func TestNsenterChildLogging(t *testing.T) {
 
 	initWaiter(t, parent)
 
-	logsDecoder := json.NewDecoder(logread)
-	var logentry *logentry
-
-	err = logsDecoder.Decode(&logentry)
-	if err != nil {
-		t.Fatalf("child log: %v", err)
-	}
-	if logentry.Level == "" || logentry.Msg == "" {
-		t.Fatalf("child log: empty log fields: level=\"%s\" msg=\"%s\"", logentry.Level, logentry.Msg)
-	}
-
+	getLogs(t, logread)
 	if err := cmd.Wait(); err != nil {
-		t.Fatalf("nsenter exits with a non-zero exit status")
+		t.Fatalf("nsenter error: %v", err)
 	}
+
+	reapChildren(t, parent)
 }
 
 func init() {
@@ -238,12 +193,19 @@ func init() {
 	}
 }
 
-func newPipe() (parent *os.File, child *os.File, err error) {
+func newPipe(t *testing.T) (parent *os.File, child *os.File) {
+	t.Helper()
 	fds, err := unix.Socketpair(unix.AF_LOCAL, unix.SOCK_STREAM|unix.SOCK_CLOEXEC, 0)
 	if err != nil {
-		return nil, nil, err
+		t.Fatal("socketpair failed:", err)
 	}
-	return os.NewFile(uintptr(fds[1]), "parent"), os.NewFile(uintptr(fds[0]), "child"), nil
+	parent = os.NewFile(uintptr(fds[1]), "parent")
+	child = os.NewFile(uintptr(fds[0]), "child")
+	t.Cleanup(func() {
+		parent.Close()
+		child.Close()
+	})
+	return
 }
 
 // initWaiter reads back the initial \0 from runc init
@@ -261,3 +223,47 @@ func initWaiter(t *testing.T, r io.Reader) {
 	}
 	t.Fatalf("waiting for init preliminary setup: %v", err)
 }
+
+func reapChildren(t *testing.T, parent *os.File) {
+	t.Helper()
+	decoder := json.NewDecoder(parent)
+	decoder.DisallowUnknownFields()
+	var pid struct {
+		Pid2 int `json:"stage2_pid"`
+		Pid1 int `json:"stage1_pid"`
+	}
+	if err := decoder.Decode(&pid); err != nil {
+		t.Fatal(err)
+	}
+
+	// Reap children.
+	_, _ = unix.Wait4(pid.Pid1, nil, 0, nil)
+	_, _ = unix.Wait4(pid.Pid2, nil, 0, nil)
+
+	// Sanity check.
+	if pid.Pid1 == 0 || pid.Pid2 == 0 {
+		t.Fatal("got pids:", pid)
+	}
+}
+
+func getLogs(t *testing.T, logread *os.File) {
+	logsDecoder := json.NewDecoder(logread)
+	logsDecoder.DisallowUnknownFields()
+	var logentry struct {
+		Level string `json:"level"`
+		Msg   string `json:"msg"`
+	}
+
+	for {
+		if err := logsDecoder.Decode(&logentry); err != nil {
+			if errors.Is(err, io.EOF) {
+				return
+			}
+			t.Fatal("init log decoding error:", err)
+		}
+		t.Logf("logentry: %+v", logentry)
+		if logentry.Level == "" || logentry.Msg == "" {
+			t.Fatalf("init log: empty log entry: %+v", logentry)
+		}
+	}
+}