Enable pod support

Share a pod with existing container, with `--net container:xxx`.

Signed-off-by: Zhang Wei <zhangwei555@huawei.com>

Author: WeiZhang555

create.go

@@ -6,6 +6,7 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"regexp"
 	"strconv"
 	"strings"
 	"syscall"
@@ -99,16 +100,25 @@ func runContainer(context *cli.Context, createOnly bool) error {
 			sharedContainer = spec.Annotations["ocid/sandbox_name"]
 		}
 	} else {
-		for _, ns := range spec.Linux.Namespaces {
+		for i, ns := range spec.Linux.Namespaces {
 			if ns.Path != "" {
-				if strings.Contains(ns.Path, "/") {
-					return fmt.Errorf("Runv doesn't support path to namespace file, it supports containers name as shared namespaces only")
-				}
 				if ns.Type == "mount" {
 					// TODO support it!
 					return fmt.Errorf("Runv doesn't support shared mount namespace currently")
 				}
-				sharedContainer = ns.Path
+				if sharedContainer, err = findSharedContainer(context.GlobalString("root"), ns.Path); err != nil {
+					return fmt.Errorf("failed to find shared container: %v", err)
+				}
+
+				cstate, err := getContainer(context, sharedContainer)
+				if err != nil {
+					return fmt.Errorf("can't get state file for container %q: %v", sharedContainer, err)
+				}
+				spec.Linux.Namespaces[i] = specs.LinuxNamespace{
+					Type: ns.Type,
+					Path: fmt.Sprintf("/proc/%d/ns/%s", cstate.InitProcessPid, ns.Type),
+				}
+
 				_, err = os.Stat(filepath.Join(root, sharedContainer, stateJson))
 				if err != nil {
 					return fmt.Errorf("The container %q is not existing or not ready", sharedContainer)
@@ -117,6 +127,10 @@ func runContainer(context *cli.Context, createOnly bool) error {
 				if err != nil {
 					return fmt.Errorf("The container %q is not ready", sharedContainer)
 				}
+
+				if err = updateSpec(spec, ocffile); err != nil {
+					return fmt.Errorf("update spec file failed: %v", err)
+				}
 			}
 		}
 	}
@@ -249,7 +263,7 @@ func createContainer(context *cli.Context, container, namespace string, config *
 		return err
 	}
 
-	return ociCreate(context, container, func(stdin, stdout, stderr string) (int, error) {
+	return ociCreate(context, container, "init", func(stdin, stdout, stderr string) (int, error) {
 		r := &types.CreateContainerRequest{
 			Id:         container,
 			Runtime:    "runv-create",
@@ -275,7 +289,7 @@ func createContainer(context *cli.Context, container, namespace string, config *
 
 }
 
-func ociCreate(context *cli.Context, container string, createFunc createFunction) error {
+func ociCreate(context *cli.Context, container, process string, createFunc createFunction) error {
 	path, err := osext.Executable()
 	if err != nil {
 		return fmt.Errorf("cannot find self executable path for %s: %v\n", os.Args[0], err)
@@ -325,7 +339,7 @@ func ociCreate(context *cli.Context, container string, createFunc createFunction
 		if context.GlobalBool("debug") {
 			args = append(args, "--debug")
 		}
-		args = append(args, "shim", "--container", container, "--process", "init")
+		args = append(args, "shim", "--container", container, "--process", process)
 		if context.String("pid-file") != "" {
 			args = append(args, "--proxy-exit-code", "--proxy-signal")
 		}
@@ -352,6 +366,7 @@ func ociCreate(context *cli.Context, container string, createFunc createFunction
 			return err
 		}
 	}
+
 	if context.String("pid-file") != "" {
 		err = createPidFile(context.String("pid-file"), cmd.Process.Pid)
 		if err != nil {
@@ -394,3 +409,37 @@ func retrieveNslPID(labels []string) int {
 	}
 	return -1
 }
+
+func findSharedContainer(root, nsPath string) (container string, err error) {
+	absRoot, err := filepath.Abs(root)
+	if err != nil {
+		return "", err
+	}
+	list, err := ioutil.ReadDir(absRoot)
+	if err != nil {
+		return "", err
+	}
+
+	if strings.Contains(nsPath, "/") {
+		pidexp := regexp.MustCompile(`/proc/(\d+)/ns/*`)
+		matches := pidexp.FindStringSubmatch(nsPath)
+		if len(matches) != 2 {
+			return "", fmt.Errorf("malformed ns path: %s", nsPath)
+		}
+		pid := matches[1]
+
+		for _, item := range list {
+			shimPidFile := filepath.Join(absRoot, item.Name(), "shim-init.pid")
+			spidByte, err := ioutil.ReadFile(shimPidFile)
+			if err != nil {
+				return "", fmt.Errorf("failed to read shim pid file %q: %v", shimPidFile, err)
+			}
+			spid := strings.TrimSpace(string(spidByte))
+			if pid == spid {
+				return item.Name(), nil
+			}
+		}
+		return "", fmt.Errorf("can't find container with shim pid %s", pid)
+	}
+	return nsPath, nil
+}

exec.go

@@ -208,7 +208,7 @@ func runProcess(context *cli.Context, container string, config *specs.Process) (
 		monitorTtySize(c, container, process)
 	}
 
-	err = ociCreate(context, container, func(stdin, stdout, stderr string) (int, error) {
+	err = ociCreate(context, container, process, func(stdin, stdout, stderr string) (int, error) {
 		p := &types.AddProcessRequest{
 			Id:       container,
 			Pid:      process,

list.go

@@ -50,7 +50,7 @@ in json format:
 		},
 	},
 	Action: func(context *cli.Context) {
-		s, err := getContainers(context)
+		s, err := getContainers(context.GlobalString("root"))
 		if err != nil {
 			fatal(err)
 		}
@@ -91,8 +91,7 @@ in json format:
 	},
 }
 
-func getContainers(context *cli.Context) ([]containerState, error) {
-	root := context.GlobalString("root")
+func getContainers(root string) ([]containerState, error) {
 	absRoot, err := filepath.Abs(root)
 	if err != nil {
 		return nil, err

shim.go

@@ -65,6 +65,26 @@ var shimCommand = cli.Command{
 			defer signal.Stop(sigc)
 		}
 
+		stateDir := filepath.Join(root, container)
+		if _, err = os.Stat(stateDir); err == nil {
+			// state dir exist, write shim pid into it
+			shimFile := filepath.Join(stateDir, "shim-"+process+".pid")
+			f, err := os.OpenFile(shimFile, os.O_WRONLY|os.O_CREATE, 0640)
+			if err != nil {
+				glog.Errorf("can't create shim pid file: %v", err)
+				goto eventHandle
+			}
+			defer f.Close()
+			shimPid := fmt.Sprintf("%d", os.Getpid())
+			_, err = f.Write([]byte(shimPid))
+			if err != nil {
+				glog.Errorf("can't write pid %q to shim pid file: %v", shimPid, err)
+				goto eventHandle
+			}
+			defer os.Remove(shimFile)
+		}
+
+	eventHandle:
 		// wait until exit
 		evChan := containerEvents(c, container)
 		for e := range evChan {

spec.go

@@ -103,3 +103,23 @@ func loadSpec(ocffile string) (*specs.Spec, error) {
 	}
 	return &spec, nil
 }
+
+func updateSpec(spec *specs.Spec, ocffile string) error {
+	if _, err := os.Stat(ocffile); err != nil {
+		if os.IsNotExist(err) {
+			return fmt.Errorf("%q doesn't exists", ocffile)
+		}
+		return fmt.Errorf("Stat %q error: %v", ocffile, err)
+	}
+
+	data, err := json.Marshal(spec)
+	if err != nil {
+		return fmt.Errorf("failed to marshal spec file during update: %v", err)
+	}
+
+	if err = ioutil.WriteFile(ocffile, data, 0640); err != nil {
+		return err
+	}
+
+	return nil
+}