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Merged
deitch merged 1 commit into from
Jan 5, 2026
Merged

properly handle partition index with get and create #336

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83 changes: 43 additions & 40 deletions disk/disk.go
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@ import (
"github.com/diskfs/go-diskfs/filesystem/iso9660"
"github.com/diskfs/go-diskfs/filesystem/squashfs"
"github.com/diskfs/go-diskfs/partition"
"github.com/diskfs/go-diskfs/partition/part"
log "github.com/sirupsen/logrus"
)

Expand Down Expand Up @@ -81,23 +82,16 @@ func (d *Disk) Partition(table partition.Table) error {
//
// returns an error if there was an error writing to the disk, reading from the reader, the table
// is invalid, or the partition is invalid
func (d *Disk) WritePartitionContents(part int, reader io.Reader) (int64, error) {
func (d *Disk) WritePartitionContents(partIndex int, reader io.Reader) (int64, error) {
backingRwFile, err := d.Backend.Writable()
if err != nil {
return -1, err
}
if d.Table == nil {
return -1, fmt.Errorf("cannot write contents of a partition on a disk without a partition table")
}
if part < 0 {
return -1, fmt.Errorf("cannot write contents of a partition without specifying a partition")
}
partitions := d.Table.GetPartitions()
// API indexes from 1, but slice from 0
if part > len(partitions) {
return -1, fmt.Errorf("cannot write contents of partition %d which is greater than max partition %d", part, len(partitions))
foundPart, err := d.GetPartition(partIndex)
if err != nil {
return -1, err
}
written, err := partitions[part-1].WriteContents(backingRwFile, reader)
written, err := foundPart.WriteContents(backingRwFile, reader)
return int64(written), err
}

Expand All @@ -107,19 +101,12 @@ func (d *Disk) WritePartitionContents(part int, reader io.Reader) (int64, error)
//
// returns an error if there was an error reading from the disk, writing to the writer, the table
// is invalid, or the partition is invalid
func (d *Disk) ReadPartitionContents(part int, writer io.Writer) (int64, error) {
if d.Table == nil {
return -1, fmt.Errorf("cannot read contents of a partition on a disk without a partition table")
}
if part < 0 {
return -1, fmt.Errorf("cannot read contents of a partition without specifying a partition")
}
partitions := d.Table.GetPartitions()
// API indexes from 1, but slice from 0
if part > len(partitions) {
return -1, fmt.Errorf("cannot read contents of partition %d which is greater than max partition %d", part, len(partitions))
func (d *Disk) ReadPartitionContents(partIndex int, writer io.Writer) (int64, error) {
foundPart, err := d.GetPartition(partIndex)
if err != nil {
return -1, err
}
return partitions[part-1].ReadContents(d.Backend, writer)
return foundPart.ReadContents(d.Backend, writer)
}

// FilesystemSpec represents the specification of a filesystem to be created
Expand Down Expand Up @@ -160,14 +147,12 @@ func (d *Disk) CreateFilesystem(spec FilesystemSpec) (filesystem.FileSystem, err
case d.Table == nil:
return nil, fmt.Errorf("cannot create filesystem on a partition without a partition table")
default:
partitions := d.Table.GetPartitions()
// API indexes from 1, but slice from 0
part := spec.Partition - 1
if spec.Partition > len(partitions) {
return nil, fmt.Errorf("cannot create filesystem on partition %d greater than maximum partition %d", spec.Partition, len(partitions))
foundPart, err := d.GetPartition(spec.Partition)
if err != nil {
return nil, err
}
size = partitions[part].GetSize()
start = partitions[part].GetStart()
size = foundPart.GetSize()
start = foundPart.GetStart()
}

switch spec.FSType {
Expand All @@ -192,27 +177,26 @@ func (d *Disk) CreateFilesystem(spec FilesystemSpec) (filesystem.FileSystem, err
//
// returns error if there was an error reading the filesystem, or the partition table is invalid and did not
// request the entire disk.
func (d *Disk) GetFilesystem(part int) (filesystem.FileSystem, error) {
func (d *Disk) GetFilesystem(partIndex int) (filesystem.FileSystem, error) {
// find out where the partition starts and ends, or if it is the entire disk
var (
size, start int64
err error
)

switch {
case part == 0:
case partIndex == 0:
size = d.Size
start = 0
case d.Table == nil:
return nil, &NoPartitionTableError{}
default:
partitions := d.Table.GetPartitions()
// API indexes from 1, but slice from 0
if part > len(partitions) {
return nil, NewMaxPartitionsExceededError(part, len(partitions))
foundPart, err := d.GetPartition(partIndex)
if err != nil {
return nil, err
}
size = partitions[part-1].GetSize()
start = partitions[part-1].GetStart()
size = foundPart.GetSize()
start = foundPart.GetStart()
}

// just try each type
Expand Down Expand Up @@ -242,7 +226,7 @@ func (d *Disk) GetFilesystem(part int) (filesystem.FileSystem, error) {
return ext4FS, nil
}
log.Debugf("ext4 failed: %v", err)
return nil, NewUnknownFilesystemError(part)
return nil, NewUnknownFilesystemError(partIndex)
}

// Close the disk. Once successfully closed, it can no longer be used.
Expand All @@ -253,3 +237,22 @@ func (d *Disk) Close() error {
*d = Disk{}
return nil
}

func (d *Disk) GetPartition(partIndex int) (part.Partition, error) {
if d.Table == nil {
return nil, &NoPartitionTableError{}
}
partitions := d.Table.GetPartitions()
// find the specific partition
var foundPart part.Partition
for _, p := range partitions {
if p.GetIndex() == partIndex {
foundPart = p
break
}
}
if foundPart == nil {
return nil, NewInvalidPartitionError(partIndex)
}
return foundPart, nil
}
36 changes: 18 additions & 18 deletions disk/disk_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -187,7 +187,7 @@ func TestWritePartitionContents(t *testing.T) {
partitionEnd := partitionStart + partitionSize/512 - 1
table := &gpt.Table{
Partitions: []*gpt.Partition{
{Start: 2048, End: partitionEnd, Type: gpt.EFISystemPartition, Name: "EFI System"},
{Index: 1, Start: 2048, End: partitionEnd, Type: gpt.EFISystemPartition, Name: "EFI System"},
},
LogicalSectorSize: 512,
}
Expand All @@ -198,9 +198,9 @@ func TestWritePartitionContents(t *testing.T) {
err error
}{
// various invalid table scenarios
{"no table, write to partition 1", nil, 1, fmt.Errorf("cannot write contents of a partition on a disk without a partition table")},
{"no table, write to partition 0", nil, 0, fmt.Errorf("cannot write contents of a partition on a disk without a partition table")},
{"no table, write to partition -1", nil, -1, fmt.Errorf("cannot write contents of a partition on a disk without a partition table")},
{"no table, write to partition 1", nil, 1, fmt.Errorf("no partition table found on disk")},
{"no table, write to partition 0", nil, 0, fmt.Errorf("no partition table found on disk")},
{"no table, write to partition -1", nil, -1, fmt.Errorf("no partition table found on disk")},
{"good table, write to partition 1", table, 1, nil},
}
for _, t2 := range tests {
Expand Down Expand Up @@ -258,7 +258,7 @@ func TestReadPartitionContents(t *testing.T) {
partitionSize := uint64(1000)
table := &gpt.Table{
Partitions: []*gpt.Partition{
{Start: partitionStart, Size: partitionSize * 512, Type: gpt.LinuxFilesystem},
{Index: 1, Start: partitionStart, Size: partitionSize * 512, Type: gpt.LinuxFilesystem},
},
LogicalSectorSize: 512,
}
Expand All @@ -269,12 +269,12 @@ func TestReadPartitionContents(t *testing.T) {
err error
}{
// various invalid table scenarios
{"no table, partition 1", nil, 1, fmt.Errorf("cannot read contents of a partition on a disk without a partition table")},
{"no table, partition 0", nil, 0, fmt.Errorf("cannot read contents of a partition on a disk without a partition table")},
{"no table, partition -1", nil, -1, fmt.Errorf("cannot read contents of a partition on a disk without a partition table")},
{"no table, partition 1", nil, 1, fmt.Errorf("no partition table found on disk")},
{"no table, partition 0", nil, 0, fmt.Errorf("no partition table found on disk")},
{"no table, partition -1", nil, -1, fmt.Errorf("no partition table found on disk")},
// invalid partition number scenarios
{"good table, partition -1", table, -1, fmt.Errorf("cannot read contents of a partition without specifying a partition")},
{"good table, partition greater than max", table, 5, fmt.Errorf("cannot read contents of partition %d which is greater than max partition %d", 5, 1)},
{"good table, partition -1", table, -1, fmt.Errorf("requested partition -1 not found")},
{"good table, partition greater than max", table, 5, fmt.Errorf("requested partition %d not found", 5)},
{"good table, good partition 1", table, 1, nil},
}
for _, t2 := range tests {
Expand Down Expand Up @@ -325,7 +325,7 @@ func TestReadPartitionContents(t *testing.T) {
partitionSize := uint32(1000)
table := &mbr.Table{
Partitions: []*mbr.Partition{
{Start: partitionStart, Size: partitionSize},
{Index: 1, Start: partitionStart, Size: partitionSize},
},
LogicalSectorSize: 512,
}
Expand All @@ -336,12 +336,12 @@ func TestReadPartitionContents(t *testing.T) {
err error
}{
// various invalid table scenarios
{"no table partition 1", nil, 1, fmt.Errorf("cannot read contents of a partition on a disk without a partition table")},
{"no table partition 0", nil, 0, fmt.Errorf("cannot read contents of a partition on a disk without a partition table")},
{"no table partition -1", nil, -1, fmt.Errorf("cannot read contents of a partition on a disk without a partition table")},
{"no table partition 1", nil, 1, fmt.Errorf("no partition table found on disk")},
{"no table partition 0", nil, 0, fmt.Errorf("no partition table found on disk")},
{"no table partition -1", nil, -1, fmt.Errorf("no partition table found on disk")},
// invalid partition number scenarios
{"valid table partition -1", table, -1, fmt.Errorf("cannot read contents of a partition without specifying a partition")},
{"valid table partition 5", table, 5, fmt.Errorf("cannot read contents of partition %d which is greater than max partition %d", 5, 1)},
{"valid table partition -1", table, -1, fmt.Errorf("requested partition -1 not found")},
{"valid table partition 5", table, 5, fmt.Errorf("requested partition %d not found", 5)},
{"valid table partition 1", table, 1, nil},
}
for _, t2 := range tests {
Expand Down Expand Up @@ -472,7 +472,7 @@ func TestCreateFilesystem(t *testing.T) {
partitionSize := uint32(20480)
table := &mbr.Table{
Partitions: []*mbr.Partition{
{Start: partitionStart, Size: partitionSize},
{Index: 1, Start: partitionStart, Size: partitionSize},
},
LogicalSectorSize: 512,
}
Expand Down Expand Up @@ -597,7 +597,7 @@ func TestGetFilesystem(t *testing.T) {
partitionSize := uint32(20480)
table := &mbr.Table{
Partitions: []*mbr.Partition{
{Start: partitionStart, Size: partitionSize},
{Index: 1, Start: partitionStart, Size: partitionSize},
},
LogicalSectorSize: 512,
}
Expand Down
14 changes: 14 additions & 0 deletions disk/error.go
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Original file line number Diff line number Diff line change
Expand Up @@ -37,3 +37,17 @@ func NewMaxPartitionsExceededError(requested, maxPart int) *MaxPartitionsExceede
max: maxPart,
}
}

type InvalidPartitionError struct {
requested int
}

func (e *InvalidPartitionError) Error() string {
return fmt.Sprintf("requested partition %d not found", e.requested)
}

func NewInvalidPartitionError(requested int) *InvalidPartitionError {
return &InvalidPartitionError{
requested: requested,
}
}