fix(usbgadget): do not panic if a change isn't found (#481)

* fix(usbgadget): do not panic if a change isn't found

* chore(usbgadget): rebind usb after updating config

internal/usbgadget/changeset_resolver.go

@@ -48,6 +48,11 @@ func (c *ChangeSetResolver) doResolveChanges(initial bool) error {
 
 	for _, key := range c.orderedChanges {
 		change := c.changesMap[key.(string)]
+		if change == nil {
+			c.l.Error().Str("key", key.(string)).Msg("fileChange not found")
+			continue
+		}
+
 		if !initial {
 			change.ResetActionResolution()
 		}
@@ -123,7 +128,11 @@ func (c *ChangeSetResolver) applyChanges() error {
 
 		err := c.changeset.applyChange(change)
 		if err != nil {
-			return err
+			if change.IgnoreErrors {
+				c.l.Warn().Str("change", change.String()).Err(err).Msg("ignoring error")
+			} else {
+				return err
+			}
 		}
 	}
 

internal/usbgadget/config.go

@@ -177,12 +177,7 @@ func (u *UsbGadget) Init() error {
 
 	u.udc = udcs[0]
 
-	err := u.WithTransaction(func() error {
+	err := u.configureUsbGadget(false)
-		u.tx.MountConfigFS()
-		u.tx.CreateConfigPath()
-		u.tx.WriteGadgetConfig()
-		return nil
-	})
 	if err != nil {
 		return u.logError("unable to initialize USB stack", err)
 	}
@@ -196,13 +191,22 @@ func (u *UsbGadget) UpdateGadgetConfig() error {
 
 	u.loadGadgetConfig()
 
-	err := u.WithTransaction(func() error {
+	err := u.configureUsbGadget(true)
-		u.tx.WriteGadgetConfig()
-		return nil
-	})
 	if err != nil {
 		return u.logError("unable to update gadget config", err)
 	}
 
 	return nil
 }
+
+func (u *UsbGadget) configureUsbGadget(resetUsb bool) error {
+	return u.WithTransaction(func() error {
+		u.tx.MountConfigFS()
+		u.tx.CreateConfigPath()
+		u.tx.WriteGadgetConfig()
+		if resetUsb {
+			u.tx.RebindUsb(true)
+		}
+		return nil
+	})
+}

internal/usbgadget/config_tx.go

@@ -319,6 +319,7 @@ func (tx *UsbGadgetTransaction) WriteUDC() {
 	// bound the gadget to a UDC (USB Device Controller)
 	path := path.Join(tx.kvmGadgetPath, "UDC")
 	tx.addFileChange("udc", RequestedFileChange{
+		Key:             "udc",
 		Path:            path,
 		ExpectedState:   FileStateFileContentMatch,
 		ExpectedContent: []byte(tx.udc),
@@ -334,6 +335,8 @@ func (tx *UsbGadgetTransaction) RebindUsb(ignoreUnbindError bool) {
 		ExpectedState:   FileStateFileWrite,
 		ExpectedContent: []byte(tx.udc),
 		Description:     "unbind UDC",
+		DependsOn:       []string{"udc"},
+		IgnoreErrors:    ignoreUnbindError,
 	})
 	// bind the gadget to the UDC
 	tx.addFileChange("udc", RequestedFileChange{
@@ -342,6 +345,5 @@ func (tx *UsbGadgetTransaction) RebindUsb(ignoreUnbindError bool) {
 		ExpectedContent: []byte(tx.udc),
 		Description:     "bind UDC",
 		DependsOn:       []string{path.Join(tx.dwc3Path, "unbind")},
-		IgnoreErrors:    ignoreUnbindError,
 	})
 }