Match-id-b6110f0a9545d2b9b48c9db37084dafe2f9bba35

runtime/main.go

@@ -0,0 +1,159 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"os"
+	"os/exec"
+	"strings"
+	"syscall"
+
+	"github.com/opencontainers/runtime-spec/specs-go"
+)
+
+const (
+	loggingPrefix       = "ascend-docker-runtime"
+	hookCli             = "ascend-docker-hook"
+	hookDefaultFilePath = "/usr/local/bin/ascend-docker-hook"
+)
+
+type args struct {
+	bundleDirPath string
+	cmd           string
+}
+
+func getArgs() (*args, error) {
+	args := &args{}
+
+	for i, param := range os.Args {
+		if param == "--bundle" || param == "-b" {
+			if len(os.Args)-i <= 1 {
+				return nil, fmt.Errorf("bundle option needs an argument\n")
+			}
+			args.bundleDirPath = os.Args[i+1]
+		} else if param == "create" {
+			args.cmd = param
+		}
+	}
+
+	return args, nil
+}
+
+func execRunc() error {
+	runcPath, err := exec.LookPath("docker-runc")
+	if err != nil {
+		runcPath, err = exec.LookPath("runc")
+		if err != nil {
+			return fmt.Errorf("failed to find the path of runc: %w\n", err)
+		}
+	}
+
+	if err = syscall.Exec(runcPath, append([]string{runcPath}, os.Args[1:]...), os.Environ()); err != nil {
+		return fmt.Errorf("failed to exec runc: %w\n", err)
+	}
+
+	return nil
+}
+
+func addHook(spec *specs.Spec) error {
+	path, err := exec.LookPath(hookCli)
+	if err != nil {
+		path = hookDefaultFilePath
+		if _, err = os.Stat(path); err != nil {
+			return fmt.Errorf("cannot find the hook\n")
+		}
+	}
+
+	if spec.Hooks == nil {
+		spec.Hooks = &specs.Hooks{}
+	} else if len(spec.Hooks.Prestart) != 0 {
+		for _, hook := range spec.Hooks.Prestart {
+			if !strings.Contains(hook.Path, hookCli) {
+				continue
+			}
+			return nil
+		}
+	}
+
+	spec.Hooks.Prestart = append(spec.Hooks.Prestart, specs.Hook{
+		Path: path,
+		Args: []string{path},
+	})
+
+	return nil
+}
+
+func modifySpecFile(path string) error {
+	stat, err := os.Stat(path)
+	if err != nil {
+		return fmt.Errorf("spec file doesnt exist %s: %w", path, err)
+	}
+
+	jsonFile, err := os.OpenFile(path, os.O_RDWR, stat.Mode())
+	if err != nil {
+		return fmt.Errorf("cannot open oci spec file %s: %w\n", path, err)
+	}
+
+	defer jsonFile.Close()
+
+	jsonContent, err := ioutil.ReadAll(jsonFile)
+	if err != nil {
+		return fmt.Errorf("failed to read oci spec file %s: %w\n", path, err)
+	}
+
+	var spec specs.Spec
+	if err := json.Unmarshal(jsonContent, &spec); err != nil {
+		return fmt.Errorf("failed to unmarshal oci spec file %s: %w\n", path, err)
+	}
+
+	if err := addHook(&spec); err != nil {
+		return fmt.Errorf("failed to inject hook: %w\n", err)
+	}
+
+	jsonOutput, err := json.Marshal(spec)
+	if err != nil {
+		return fmt.Errorf("failed to marshal OCI spec file: %w\n", err)
+	}
+
+	if _, err := jsonFile.WriteAt(jsonOutput, 0); err != nil {
+		return fmt.Errorf("failed to write OCI spec file: %w\n", err)
+	}
+
+	return nil
+}
+
+func doProcess() error {
+	args, err := getArgs()
+	if err != nil {
+		return fmt.Errorf("failed to get args: %w\n", err)
+	}
+
+	if args.cmd != "create" {
+		return execRunc()
+	}
+
+	if args.bundleDirPath == "" {
+		args.bundleDirPath, err = os.Getwd()
+		if err != nil {
+			return fmt.Errorf("failed to get current working dir: %w\n", err)
+		}
+	}
+
+	specFilePath := args.bundleDirPath + "/config.json"
+
+	if err := modifySpecFile(specFilePath); err != nil {
+		return fmt.Errorf("failed to modify spec file %s: %w\n", specFilePath, err)
+	}
+
+	return execRunc()
+}
+
+func main() {
+	log.SetPrefix(loggingPrefix)
+
+	if err := doProcess(); err != nil {
+		log.Fatal(err)
+	}
+}