remove legacy registry entry

if users have legacy VMs (podman machines having hvsock registry entries
with the machineName field) when using podman with this patch, their
Registry entries will never be deleted by the functions added in
previous commits.

This commit adds a helper func to clean the Registry when these legacy
machines get removed

Signed-off-by: lstocchi <lstocchi@redhat.com>

pkg/machine/hyperv/stubber.go

@@ -177,7 +177,7 @@ func (h HyperVStubber) Remove(mc *vmconfigs.MachineConfig) ([]string, func() err
 	//
 	// This is to prevent a non-admin user from deleting the last machine
 	// which would require removal of vsock entries from the Windows Registry.
-	if err := h.canRemove(); err != nil {
+	if err := h.canRemove(mc); err != nil {
 		return nil, nil, err
 	}
 
@@ -200,9 +200,13 @@ func (h HyperVStubber) Remove(mc *vmconfigs.MachineConfig) ([]string, func() err
 		}
 
 		// remove vsock registry entries
+		if isLegacyMachine(mc) {
+			removeLegacyHvSockEntries(mc)
+		} else {
 			if err := h.removeHvSockFromRegistry(); err != nil {
 				logrus.Errorf("unable to remove hvsock registry entries: %q", err)
 			}
+		}
 
 		return nil
 	}
@@ -232,11 +236,21 @@ func (h HyperVStubber) canCreate() error {
 	return ErrHypervUserNotInAdminGroup
 }
 
-func (h HyperVStubber) canRemove() error {
+func isLegacyMachine(mc *vmconfigs.MachineConfig) bool {
+	return mc.HyperVHypervisor != nil && mc.HyperVHypervisor.ReadyVsock.MachineName != ""
+}
+
+func (h HyperVStubber) canRemove(mc *vmconfigs.MachineConfig) error {
 	// if admin, can always remove
 	if windows.HasAdminRights() {
 		return nil
 	}
+
+	// if machine is legacy (machineName field), require admin rights to remove
+	if isLegacyMachine(mc) {
+		return ErrHypervRegistryRemoveRequiresElevation
+	}
+
 	// not admin, check if there are multiple machines
 	// if so, user could remove the machine just by being member of the hyperv admin group
 	// (only the last machine removal requires Registry changes)
@@ -270,6 +284,45 @@ func (h HyperVStubber) countMachinesWithToolname() (int, error) {
 	return count, nil
 }
 
+// removeLegacyHvSockEntries removes any legacy HVSOCK registry entries associated with the machine.
+// This is used to clean up entries from older versions of Podman that did not manage the Toolname field.
+func removeLegacyHvSockEntries(mc *vmconfigs.MachineConfig) {
+	if mc.HyperVHypervisor.NetworkVSock.MachineName != "" {
+		// Remove the HVSOCK for networking
+		if err := mc.HyperVHypervisor.NetworkVSock.Remove(); err != nil {
+			logrus.Errorf("unable to remove registry entry for %s: %q", mc.HyperVHypervisor.NetworkVSock.KeyName, err)
+		}
+	}
+
+	if mc.HyperVHypervisor.ReadyVsock.MachineName != "" {
+		// Remove the HVSOCK for events
+		if err := mc.HyperVHypervisor.ReadyVsock.Remove(); err != nil {
+			logrus.Errorf("unable to remove registry entry for %s: %q", mc.HyperVHypervisor.ReadyVsock.KeyName, err)
+		}
+	}
+
+	for _, mount := range mc.Mounts {
+		if mount.VSockNumber == nil {
+			// nothing to do if the vsock number was never defined
+			continue
+		}
+
+		vsockReg, err := vsock.LoadHVSockRegistryEntry(*mount.VSockNumber)
+		if err != nil {
+			logrus.Debugf("Vsock %d for mountpoint %s does not have a valid registry entry, skipping removal", *mount.VSockNumber, mount.Target)
+			continue
+		}
+
+		if vsockReg.MachineName == "" {
+			continue
+		}
+
+		if err := vsockReg.Remove(); err != nil {
+			logrus.Debugf("unable to remove vsock %d for mountpoint %s: %v", *mount.VSockNumber, mount.Target, err)
+		}
+	}
+}
+
 func (h HyperVStubber) removeHvSockFromRegistry() error {
 	// Remove hvsock registry entries only if this is the last machine
 	machines, err := h.countMachinesWithToolname()

pkg/machine/hyperv/vsock/vsock.go

@@ -244,11 +244,17 @@ func LoadHVSockRegistryEntry(port uint64) (*HVSockRegistryEntry, error) {
 		return nil, err
 	}
 
+	m, _, err := k.GetStringValue(HvsockMachineName)
+	if err != nil {
+		return nil, err
+	}
+
 	return &HVSockRegistryEntry{
 		KeyName:     keyName,
 		Purpose:     purpose,
 		Port:        port,
 		Key:         k,
+		MachineName: m,
 	}, nil
 }