linuxrun: add -vsock-ports option to HyperKit

When `-vsock-ports` is specified, the listed guest vsock
ports will be made available through unix domain sockets
in the state directory.

Signed-off-by: Magnus Skjegstad <magnus@skjegstad.com>

src/cmd/linuxkit/run_hyperkit.go

@@ -32,6 +32,7 @@ func runHyperKit(args []string) {
 	data := flags.String("data", "", "Metadata to pass to VM (either a path to a file or a string)")
 	ipStr := flags.String("ip", "", "IP address for the VM")
 	state := flags.String("state", "", "Path to directory to keep VM state in")
+	vsockports := flags.String("vsock-ports", "", "List of vsock ports to forward from the guest on startup (comma separated). A unix domain socket for each port will be created in the state directory")
 
 	if err := flags.Parse(args); err != nil {
 		log.Fatal("Unable to parse args")
@@ -100,6 +101,10 @@ func runHyperKit(args []string) {
 		log.Fatalln("Error creating hyperkit: ", err)
 	}
 
+	if h.VSockPorts, err = stringToIntArray(*vsockports, ","); err != nil {
+		log.Fatalln("Unable to parse vsock-ports: ", err)
+	}
+
 	h.Kernel = prefix + "-kernel"
 	h.Initrd = prefix + "-initrd.img"
 	h.VPNKitKey = vpnKitKey

src/cmd/linuxkit/util.go

@@ -3,6 +3,7 @@ package main
 import (
 	"os"
 	"strconv"
+	"strings"
 )
 
 func getStringValue(envKey string, flagVal string, defaultVal string) string {
@@ -81,3 +82,18 @@ func getBoolValue(envKey string, flagVal bool) bool {
 
 	return res
 }
+
+func stringToIntArray(l string, sep string) ([]int, error) {
+	var err error
+	if l == "" {
+		return []int{}, err
+	}
+	s := strings.Split(l, sep)
+	i := make([]int, len(s))
+	for idx := range s {
+		if i[idx], err = strconv.Atoi(s[idx]); err != nil {
+			return nil, err
+		}
+	}
+	return i, nil
+}