add patch for older devices (danielpaulus#61)

image mount and list should work now for older devices

Author: danielpaulus

ios/imagemounter/imagemounter.go

@@ -3,6 +3,7 @@ package imagemounter
 import (
 	"errors"
 	"fmt"
+	"github.com/Masterminds/semver"
 	"github.com/danielpaulus/go-ios/ios"
 	log "github.com/sirupsen/logrus"
 	"io"
@@ -16,17 +17,23 @@ const serviceName string = "com.apple.mobile.mobile_image_mounter"
 type Connection struct {
 	deviceConn ios.DeviceConnectionInterface
 	plistCodec ios.PlistCodec
+	version    *semver.Version
 }
 
 //New returns a new mobile image mounter Connection for the given DeviceID and Udid
 func New(device ios.DeviceEntry) (*Connection, error) {
+	version, err := ios.GetProductVersion(device)
+	if err != nil {
+		return nil, err
+	}
 	deviceConn, err := ios.ConnectToService(device, serviceName)
 	if err != nil {
 		return &Connection{}, err
 	}
 	return &Connection{
 		deviceConn: deviceConn,
 		plistCodec: ios.NewPlistCodec(),
+		version:    version,
 	}, nil
 }
 
@@ -56,9 +63,13 @@ func (conn *Connection) ListImages() ([][]byte, error) {
 	if ok {
 		return nil, fmt.Errorf("device error: %v", deviceError)
 	}
+
 	signatures, ok := resp["ImageSignature"]
 	if !ok {
-		return nil, fmt.Errorf("invalid response: %+v", signatures)
+		if conn.version.LessThan(semver.MustParse("14.0")) {
+			return [][]byte{}, nil
+		}
+		return nil, fmt.Errorf("invalid response: %+v", resp)
 	}
 
 	array, ok := signatures.([]interface{})

ios/lockdown_value.go

@@ -3,6 +3,7 @@ package ios
 import (
 	"bytes"
 	"fmt"
+	"github.com/Masterminds/semver"
 
 	plist "howett.net/plist"
 )
@@ -150,6 +151,21 @@ func (lockDownConn *LockDownConnection) GetValues() (GetAllValuesResponse, error
 	return response, nil
 }
 
+//GetProductVersion gets the iOS version of a device
+func GetProductVersion(device DeviceEntry) (*semver.Version, error) {
+	lockdownConnection, err := ConnectLockdownWithSession(device)
+	if err != nil {
+		return &semver.Version{}, err
+	}
+	defer lockdownConnection.Close()
+	version, err := lockdownConnection.GetProductVersion()
+	if err != nil {
+		return &semver.Version{}, err
+	}
+	v, err := semver.NewVersion(version)
+	return v, err
+}
+
 //GetProductVersion returns the ProductVersion of the device f.ex. "10.3"
 func (lockDownConn *LockDownConnection) GetProductVersion() (string, error) {
 	msg, err := lockDownConn.GetValue("ProductVersion")