distro: define PartitionType method on ImageType

This is needed so that we can do different things depending on the 
given layout; this will be used in tests for now only. Only GPT
allows for arbitrary number of partitions and once we assert this
in code we will need to adjust the tests accordingly.

NB: This method might be removed again in the future, once generic
LVM support is added everywhere and the ability to differentiate 
between MBR and GPT layouts is not needed anymore.

internal/distro/distro.go

@@ -97,6 +97,10 @@ type ImageType interface {
 	// is 0 the default value for the format will be returned.
 	Size(size uint64) uint64
 
+	// Returns the corresponding partion type ("gpt", "dos") or "" the image type
+	// has no partition table. Only support for RHEL 8.5+
+	PartitionType() string
+
 	// Returns the sets of packages to include and exclude when building the image.
 	// Indexed by a string label. How each set is labeled and used depends on the
 	// image type.

internal/distro/fedora33/distro.go

@@ -192,6 +192,10 @@ func (t *imageType) Size(size uint64) uint64 {
 	return size
 }
 
+func (t *imageType) PartitionType() string {
+	return ""
+}
+
 func (t *imageType) Packages(bp blueprint.Blueprint) ([]string, []string) {
 	packages := append(t.packages, bp.GetPackages()...)
 	timezone, _ := bp.Customizations.GetTimezoneSettings()

internal/distro/rhel8/distro.go

@@ -184,6 +184,10 @@ func (t *imageType) Size(size uint64) uint64 {
 	return size
 }
 
+func (t *imageType) PartitionType() string {
+	return ""
+}
+
 func (t *imageType) Packages(bp blueprint.Blueprint) ([]string, []string) {
 	packages := append(t.packages, bp.GetPackages()...)
 	timezone, _ := bp.Customizations.GetTimezoneSettings()

internal/distro/rhel84/distro.go

@@ -215,6 +215,10 @@ func (t *imageType) Size(size uint64) uint64 {
 	return size
 }
 
+func (t *imageType) PartitionType() string {
+	return ""
+}
+
 func (t *imageType) Packages(bp blueprint.Blueprint) ([]string, []string) {
 	packages := append(t.packages, bp.GetPackages()...)
 	timezone, _ := bp.Customizations.GetTimezoneSettings()

internal/distro/rhel84/distro_v2.go

@@ -68,6 +68,10 @@ func (t *imageTypeS2) Size(size uint64) uint64 {
 	return size
 }
 
+func (t *imageTypeS2) PartitionType() string {
+	return ""
+}
+
 func (t *imageTypeS2) Packages(bp blueprint.Blueprint) ([]string, []string) {
 	packages := append(t.packageSets["packages"].Include, bp.GetPackages()...)
 	timezone, _ := bp.Customizations.GetTimezoneSettings()

internal/distro/rhel85/distro.go

@@ -327,6 +327,16 @@ func (t *imageType) getPartitionTable(
 	return disk.CreatePartitionTable(mountpoints, imageSize, &basePartitionTable, rng)
 }
 
+func (t *imageType) PartitionType() string {
+	archName := t.arch.Name()
+	basePartitionTable, exists := t.basePartitionTables[archName]
+	if !exists {
+		return ""
+	}
+
+	return basePartitionTable.Type
+}
+
 // local type for ostree commit metadata used to define commit sources
 type ostreeCommit struct {
 	Checksum string

internal/distro/rhel86/distro.go

@@ -404,6 +404,17 @@ func (t *imageType) getDefaultImageConfig() *distro.ImageConfig {
 		imageConfig = &distro.ImageConfig{}
 	}
 	return imageConfig.InheritFrom(t.arch.distro.getDefaultImageConfig())
+
+}
+
+func (t *imageType) PartitionType() string {
+	archName := t.arch.Name()
+	basePartitionTable, exists := t.basePartitionTables[archName]
+	if !exists {
+		return ""
+	}
+
+	return basePartitionTable.Type
 }
 
 // local type for ostree commit metadata used to define commit sources

internal/distro/rhel90/distro.go

@@ -392,6 +392,17 @@ func (t *imageType) getDefaultImageConfig() *distro.ImageConfig {
 		imageConfig = &distro.ImageConfig{}
 	}
 	return imageConfig.InheritFrom(t.arch.distro.getDefaultImageConfig())
+
+}
+
+func (t *imageType) PartitionType() string {
+	archName := t.arch.Name()
+	basePartitionTable, exists := t.basePartitionTables[archName]
+	if !exists {
+		return ""
+	}
+
+	return basePartitionTable.Type
 }
 
 // local type for ostree commit metadata used to define commit sources

internal/distro/rhel90beta/distro.go

@@ -362,6 +362,16 @@ func (t *imageType) getPartitionTable(
 	return disk.CreatePartitionTable(mountpoints, imageSize, &basePartitionTable, rng)
 }
 
+func (t *imageType) PartitionType() string {
+	archName := t.arch.Name()
+	basePartitionTable, exists := t.basePartitionTables[archName]
+	if !exists {
+		return ""
+	}
+
+	return basePartitionTable.Type
+}
+
 // local type for ostree commit metadata used to define commit sources
 type ostreeCommit struct {
 	Checksum string

internal/distro/test_distro/distro.go

@@ -167,6 +167,10 @@ func (t *TestImageType) Size(size uint64) uint64 {
 	return 0
 }
 
+func (t *TestImageType) PartitionType() string {
+	return ""
+}
+
 func (t *TestImageType) Packages(bp blueprint.Blueprint) ([]string, []string) {
 	return nil, nil
 }