Avoid changing roots in grub if running abroot on previous partition

core/disk-manager.go

@@ -39,9 +39,9 @@ type Partition struct {
 	Device string
 
 	// If the partition is LUKS-encrypted or an LVM volume, the logical volume
-	// opened in /dev/mapper will be a child of the physical partiiton in /dev.
+	// opened in /dev/mapper will be a child of the physical partition in /dev.
 	// Otherwise, the partition will be a direct child of the block device, and
-	// its Parent will be nil.
+	// Parent will be nil.
 	//
 	// The same logic applies for encrypted LVM volumes. When this is the case,
 	// the filesystem hirearchy is as follows:

core/grub.go

@@ -24,8 +24,8 @@ import (
 )
 
 type Grub struct {
-	presentRoot string
-	futureRoot  string
+	PresentRoot string
+	FutureRoot  string
 }
 
 // generateABGrubConf generates a new grub config with the given details
@@ -160,7 +160,21 @@ func NewGrub(bootPart Partition) (*Grub, error) {
 	}
 
 	return &Grub{
-		presentRoot: presentRoot,
-		futureRoot:  futureRoot,
+		PresentRoot: presentRoot,
+		FutureRoot:  futureRoot,
 	}, nil
 }
+
+func (g *Grub) IsBootedIntoPresentRoot() (bool, error) {
+	a := NewABRootManager()
+	future, err := a.GetFuture()
+	if err != nil {
+		return false, err
+	}
+
+	if g.FutureRoot == "a" {
+		return future.Label == settings.Cnf.PartLabelA, nil
+	} else {
+		return future.Label == settings.Cnf.PartLabelB, nil
+	}
+}

core/root.go

@@ -27,8 +27,8 @@ type ABRootManager struct {
 
 // ABRootPartition represents an ABRoot partition
 type ABRootPartition struct {
-	Label        string // a,b
-	IdentifiedAs string // present,future
+	Label        string // Matches `partLabelA` and `partLabelB` settings entries
+	IdentifiedAs string // Either `present` or `future`
 	Partition    Partition
 	MountPoint   string
 	MountOptions string

core/system.go

@@ -908,7 +908,13 @@ func (s *ABSystem) RunOperation(operation ABSystemOperation) error {
 		return err
 	}
 
-	if grub.futureRoot != partFuture.Label {
+	// Only swap grub entries if we're booted into the present partition
+	isPresent, err := grub.IsBootedIntoPresentRoot()
+	if err != nil {
+		PrintVerbose("ABSystem.RunOperation:err(11.1): %s", err)
+		return err
+	}
+	if isPresent {
 		grubCfgCurrent := filepath.Join(tmpBootMount, "grub/grub.cfg")
 		grubCfgFuture := filepath.Join(tmpBootMount, "grub/grub.cfg.future")
 
@@ -918,11 +924,11 @@ func (s *ABSystem) RunOperation(operation ABSystemOperation) error {
 
 			grubCfgContents, err := os.ReadFile(grubCfgCurrent)
 			if err != nil {
-				PrintVerbose("ABSystem.RunOperation:err(11.1): %s", err)
+				PrintVerbose("ABSystem.RunOperation:err(11.2): %s", err)
 			}
 
 			var replacerPairs []string
-			if grub.futureRoot == "a" {
+			if grub.FutureRoot == "a" {
 				replacerPairs = []string{
 					"default=1", "default=0",
 					"A (previous)", "A (current)",
@@ -942,7 +948,7 @@ func (s *ABSystem) RunOperation(operation ABSystemOperation) error {
 
 		err = AtomicSwap(grubCfgCurrent, grubCfgFuture)
 		if err != nil {
-			PrintVerbose("ABSystem.RunOperation:err(11.2): %s", err)
+			PrintVerbose("ABSystem.RunOperation:err(11.3): %s", err)
 			return err
 		}
 	}