gadget: remove offset-write from gadget structure content

Using offset-write from an image in a gadget volume structure content was never implemented by ubuntu-image and does not seem too useful. Removing it and the related checks therefore. 

4 files changed, 10 insertions, 123 deletions

diff --git a/gadget/gadget.go b/gadget/gadget.go
index 538f9c6122..20510a52a2 100644
--- a/gadget/gadget.go
+++ b/gadget/gadget.go
@@ -353,10 +353,6 @@ type VolumeContent struct {
	Image string `yaml:"image" json:"image"`
	// Offset the image is written at
	Offset *quantity.Offset `yaml:"offset" json:"offset"`
-	// OffsetWrite describes a 32-bit address, within the volume, at which
-	// the offset of current image will be written. The position may be
-	// specified as a byte offset relative to the start of a named structure
-	OffsetWrite *RelativeOffset `yaml:"offset-write" json:"offset-write"`
	// Size of the image, when empty size is calculated by looking at the
	// image
	Size quantity.Size `yaml:"size" json:"size"`
@@ -1180,16 +1176,6 @@ func validateCrossVolumeStructure(structures []VolumeStructure, knownStructures
	// content relative offset only possible if it's a bare structure
	continue
	}
-	for cidx, c := range ps.Content {
-	if c.OffsetWrite == nil || c.OffsetWrite.RelativeTo == "" {
-	continue
-	}
-	relativeToStructure := knownStructures[c.OffsetWrite.RelativeTo]
-	if relativeToStructure == nil {
-	return fmt.Errorf("structure %q, content %v refers to an unknown structure %q",
-	ps.Name, fmtIndexAndName(cidx, c.Image), c.OffsetWrite.RelativeTo)
-	}
-	}
	}
	return nil
 }
@@ -1359,7 +1345,7 @@ func validateBareContent(vc *VolumeContent) error {
 }
 
 func validateFilesystemContent(vc *VolumeContent) error {
-	if vc.Image != "" || vc.Offset != nil || vc.OffsetWrite != nil || vc.Size != 0 {
+	if vc.Image != "" || vc.Offset != nil || vc.Size != 0 {
	return fmt.Errorf("cannot use image content for non-bare file system")
	}
	if vc.UnresolvedSource == "" {
diff --git a/gadget/gadget_test.go b/gadget/gadget_test.go
index 85461e8af8..17f5e57d90 100644
--- a/gadget/gadget_test.go
+++ b/gadget/gadget_test.go
@@ -1669,29 +1669,12 @@ volumes:
 content:
 - image: pc-core.img
 `
-	gadgetYamlBadContentName := gadgetYamlHeader + `
- - name: other-name
- type: DA,21686148-6449-6E6F-744E-656564454649
- size: 1M
- offset: 1M
- offset-write: my-name-is+92
- content:
- - image: pc-core.img
- offset-write: bad-name+123
-`
 
	err := ioutil.WriteFile(s.gadgetYamlPath, []byte(gadgetYamlBadStructureName), 0644)
	c.Assert(err, IsNil)
 
	_, err = gadget.ReadInfo(s.dir, nil)
	c.Check(err, ErrorMatches, `invalid volume "pc": structure "other-name" refers to an unknown structure "bad-name"`)
-
-	err = ioutil.WriteFile(s.gadgetYamlPath, []byte(gadgetYamlBadContentName), 0644)
-	c.Assert(err, IsNil)
-
-	_, err = gadget.ReadInfo(s.dir, nil)
-	c.Check(err, ErrorMatches, `invalid volume "pc": structure "other-name", content #0 \("pc-core.img"\) refers to an unknown structure "bad-name"`)
-
 }
 
 func (s *gadgetYamlTestSuite) TestValidateStructureUpdatePreserveOnlyForFs(c *C) {
@@ -4018,7 +4001,6 @@ func (s *gadgetYamlTestSuite) TestGadgetInfoVolumeStructureInternalFieldsNoJSON(
	Target: "some-target",
	Image: "image",
	Offset: asOffsetPtr(12),
-	OffsetWrite: mustParseGadgetRelativeOffset(c, "mbr+192"),
	Size: 321,
	Unpack: true,
	},
@@ -4031,7 +4013,7 @@ func (s *gadgetYamlTestSuite) TestGadgetInfoVolumeStructureInternalFieldsNoJSON(
	b, err := json.Marshal(volS)
	c.Assert(err, IsNil)
	// ensure the json looks json-ish
-	c.Check(string(b), Equals, `{"name":"pc","filesystem-label":"ubuntu-seed","offset":123,"offset-write":{"relative-to":"mbr","offset":92},"min-size":0,"size":888,"type":"0C","role":"system-seed","id":"gpt-id","filesystem":"vfat","content":[{"source":"source","target":"some-target","image":"image","offset":12,"offset-write":{"relative-to":"mbr","offset":192},"size":321,"unpack":true}],"update":{"edition":2,"preserve":["foo"]}}`)
+	c.Check(string(b), Equals, `{"name":"pc","filesystem-label":"ubuntu-seed","offset":123,"offset-write":{"relative-to":"mbr","offset":92},"min-size":0,"size":888,"type":"0C","role":"system-seed","id":"gpt-id","filesystem":"vfat","content":[{"source":"source","target":"some-target","image":"image","offset":12,"size":321,"unpack":true}],"update":{"edition":2,"preserve":["foo"]}}`)
 
	// check that the new structure has no volumeName
	var newVolS *gadget.VolumeStructure
diff --git a/gadget/layout.go b/gadget/layout.go
index 0a0f21086b..d3214bb71d 100644
--- a/gadget/layout.go
+++ b/gadget/layout.go
@@ -150,9 +150,6 @@ type LaidOutContent struct {
 
	// StartOffset defines the start offset of this content image
	StartOffset quantity.Offset
-	// AbsoluteOffsetWrite is the resolved absolute position of offset-write
-	// for this content element within the enclosing volume
-	AbsoluteOffsetWrite *quantity.Offset
	// Size is the maximum size occupied by this image
	Size quantity.Size
	// Index of the content in structure declaration inside gadget YAML
@@ -178,9 +175,8 @@ type ResolvedContent struct {
	KernelUpdate bool
 }
 
-func layoutVolumeStructures(volume *Volume) (structures []LaidOutStructure, byName map[string]*LaidOutStructure, err error) {
+func layoutVolumeStructures(volume *Volume) (structures []LaidOutStructure, err error) {
	structures = make([]LaidOutStructure, len(volume.Structure))
-	byName = make(map[string]*LaidOutStructure, len(volume.Structure))
 
	// Even although we do not have the final offset as that depends on the
	// state of the installation disk and we do not know at this point, we
@@ -192,9 +188,6 @@ func layoutVolumeStructures(volume *Volume) (structures []LaidOutStructure, byNa
	VolumeStructure: &volume.Structure[idx],
	}
 
-	if ps.Name() != "" {
-	byName[ps.Name()] = &ps
-	}
	if volume.Structure[idx].Offset != nil {
	offset = *volume.Structure[idx].Offset
	}
@@ -217,23 +210,23 @@ func layoutVolumeStructures(volume *Volume) (structures []LaidOutStructure, byNa
	previousEnd := quantity.Offset(0)
	for idx, ps := range structures {
	if ps.StartOffset < previousEnd {
-	return nil, nil, fmt.Errorf("cannot lay out volume, structure %v overlaps with preceding structure %v", ps, structures[idx-1])
+	return nil, fmt.Errorf("cannot lay out volume, structure %v overlaps with preceding structure %v", ps, structures[idx-1])
	}
	previousEnd = ps.StartOffset + quantity.Offset(ps.VolumeStructure.Size)
 
	offsetWrite, err := resolveOffsetWrite(ps.VolumeStructure.OffsetWrite, byName)
	if err != nil {
-	return nil, nil, fmt.Errorf("cannot resolve offset-write of structure %v: %v", ps, err)
+	return nil, fmt.Errorf("cannot resolve offset-write of structure %v: %v", ps, err)
	}
	structures[idx].AbsoluteOffsetWrite = offsetWrite
	}
 
-	return structures, byName, nil
+	return structures, nil
 }
 
 // LayoutVolumePartially attempts to lay out only the structures in the volume.
 func LayoutVolumePartially(volume *Volume) (*PartiallyLaidOutVolume, error) {
-	structures, _, err := layoutVolumeStructures(volume)
+	structures, err := layoutVolumeStructures(volume)
	if err != nil {
	return nil, err
	}
@@ -283,7 +276,7 @@ func LayoutVolume(volume *Volume, opts *LayoutOptions) (*LaidOutVolume, error) {
	}
	}
 
-	structures, byName, err := layoutVolumeStructures(volume)
+	structures, err := layoutVolumeStructures(volume)
	if err != nil {
	return nil, err
	}
@@ -308,15 +301,10 @@ func LayoutVolume(volume *Volume, opts *LayoutOptions) (*LaidOutVolume, error) {
	// has a size so even without the structure content the layout
	// can be calculated.
	if !opts.IgnoreContent {
-	content, err := layOutStructureContent(opts.GadgetRootDir, &structures[idx], byName)
+	content, err := layOutStructureContent(opts.GadgetRootDir, &structures[idx])
	if err != nil {
	return nil, err
	}
-	for _, c := range content {
-	if c.AbsoluteOffsetWrite != nil && *c.AbsoluteOffsetWrite > fartherstOffsetWrite {
-	fartherstOffsetWrite = *c.AbsoluteOffsetWrite
-	}
-	}
	structures[idx].LaidOutContent = content
	}
 
@@ -448,7 +436,7 @@ func getImageSize(path string) (quantity.Size, error) {
	return quantity.Size(stat.Size()), nil
 }
 
-func layOutStructureContent(gadgetRootDir string, ps *LaidOutStructure, known map[string]*LaidOutStructure) ([]LaidOutContent, error) {
+func layOutStructureContent(gadgetRootDir string, ps *LaidOutStructure) ([]LaidOutContent, error) {
	if ps.HasFilesystem() {
	// structures with a filesystem do not need any extra layout
	return nil, nil
@@ -482,18 +470,11 @@ func layOutStructureContent(gadgetRootDir string, ps *LaidOutStructure, known ma
	actualSize = c.Size
	}
 
-	offsetWrite, err := resolveOffsetWrite(c.OffsetWrite, known)
-	if err != nil {
-	return nil, fmt.Errorf("cannot resolve offset-write of structure %v content %q: %v", ps, c.Image, err)
-	}
-
	content[idx] = LaidOutContent{
	VolumeContent: &ps.VolumeStructure.Content[idx],
	Size: actualSize,
	StartOffset: ps.StartOffset + start,
	Index: idx,
-	// break for gofmt < 1.11
-	AbsoluteOffsetWrite: offsetWrite,
	}
	previousEnd = start + quantity.Offset(actualSize)
	if quantity.Size(previousEnd) > ps.VolumeStructure.Size {
diff --git a/gadget/layout_test.go b/gadget/layout_test.go
index d9df478350..4446394038 100644
--- a/gadget/layout_test.go
+++ b/gadget/layout_test.go
@@ -916,8 +916,6 @@ volumes:
	VolumeContent: &vol.Structure[1].Content[0],
	Size: 200 * quantity.SizeKiB,
	StartOffset: 1 * quantity.OffsetMiB,
-	// offset-write: bar+10
-	AbsoluteOffsetWrite: asOffsetPtr(2*quantity.OffsetMiB + 10),
	},
	},
	}, {
@@ -936,8 +934,6 @@ volumes:
	VolumeContent: &vol.Structure[2].Content[0],
	Size: 150 * quantity.SizeKiB,
	StartOffset: 2 * quantity.OffsetMiB,
-	// offset-write: bar+10
-	AbsoluteOffsetWrite: asOffsetPtr(450),
	},
	},
	},
@@ -961,25 +957,6 @@ func (p *layoutTestSuite) TestLayoutVolumeOffsetWriteBadRelativeTo(c *C) {
	},
	},
	}
-	volBadContent := gadget.Volume{
-	Structure: []gadget.VolumeStructure{
-	{
-	Name: "foo",
-	Type: "DA,21686148-6449-6E6F-744E-656564454649",
-	Offset: asOffsetPtr(0),
-	Size: 1 * quantity.SizeMiB,
-	Content: []gadget.VolumeContent{
-	{
-	Image: "foo.img",
-	OffsetWrite: &gadget.RelativeOffset{
-	RelativeTo: "bar",
-	Offset: 10,
-	},
-	},
-	},
-	},
-	},
-	}
 
	makeSizedFile(c, filepath.Join(p.dir, "foo.img"), 200*quantity.SizeKiB, []byte(""))
 
@@ -987,10 +964,6 @@ func (p *layoutTestSuite) TestLayoutVolumeOffsetWriteBadRelativeTo(c *C) {
	v, err := gadget.LayoutVolume(&volBadStructure, opts)
	c.Check(v, IsNil)
	c.Check(err, ErrorMatches, `cannot resolve offset-write of structure #0 \("foo"\): refers to an unknown structure "bar"`)
-
-	v, err = gadget.LayoutVolume(&volBadContent, opts)
-	c.Check(v, IsNil)
-	c.Check(err, ErrorMatches, `cannot resolve offset-write of structure #0 \("foo"\) content "foo.img": refers to an unknown structure "bar"`)
 }
 
 func (p *layoutTestSuite) TestLayoutVolumeOffsetWriteEnlargesVolume(c *C) {
@@ -1017,41 +990,6 @@ volumes:
	c.Assert(err, IsNil)
	// offset-write is at 1GB
	c.Check(v.Size, Equals, 1*quantity.SizeGiB+gadget.SizeLBA48Pointer)
-
-	var gadgetYamlContent = `
-volumes:
- pc:
- bootloader: grub
- structure:
- - name: mbr
- type: mbr
- size: 440
- - name: foo
- type: DA,21686148-6449-6E6F-744E-656564454649
- size: 1M
- offset: 1M
- content:
- - image: foo.img
- # 2GB
- offset-write: mbr+2147483648
- - image: bar.img
- # 1GB
- offset-write: mbr+1073741824
- - image: baz.img
- # 3GB
- offset-write: mbr+3221225472
-
-`
-	makeSizedFile(c, filepath.Join(p.dir, "foo.img"), 200*quantity.SizeKiB, []byte(""))
-	makeSizedFile(c, filepath.Join(p.dir, "bar.img"), 150*quantity.SizeKiB, []byte(""))
-	makeSizedFile(c, filepath.Join(p.dir, "baz.img"), 100*quantity.SizeKiB, []byte(""))
-
-	vol = mustParseVolume(c, gadgetYamlContent, "pc")
-
-	v, err = gadget.LayoutVolume(vol, opts)
-	c.Assert(err, IsNil)
-	// foo.img offset-write is at 3GB
-	c.Check(v.Size, Equals, 3*quantity.SizeGiB+gadget.SizeLBA48Pointer)
 }
 
 func (p *layoutTestSuite) TestLayoutVolumePartialNoSuchFile(c *C) {