move to pkg/btrfs, get CRC working

2 files changed, 4 insertions, 223 deletions

diff --git a/cmd/btrfs-dbg/main.go b/cmd/btrfs-dbg/main.go
index 0990378..3d2103a 100644
--- a/cmd/btrfs-dbg/main.go
+++ b/cmd/btrfs-dbg/main.go
@@ -6,7 +6,7 @@ import (
 
 	"github.com/davecgh/go-spew/spew"
 
-	"lukeshu.com/btrfs-tools/pkg/binstruct"
+	"lukeshu.com/btrfs-tools/pkg/btrfs"
 )
 
 func main() {
@@ -27,7 +27,7 @@ func Main(imgfilename string) (err error) {
 	if err != nil {
 		return err
 	}
-	img := &Img{
+	img := &btrfs.Img{
 		File: fh,
 	}
 	defer func() {
@@ -42,8 +42,8 @@ func Main(imgfilename string) (err error) {
 	spew := spew.NewDefaultConfig()
 	spew.DisablePointerAddresses = true
 
-	spew.Dump(superblocks[0].data)
-	sum, err := superblocks[0].data.CalculateChecksum()
+	spew.Dump(superblocks[0].Data)
+	sum, err := superblocks[0].Data.CalculateChecksum()
 	if err != nil {
 		return err
 	}
@@ -51,66 +51,3 @@ func Main(imgfilename string) (err error) {
 
 	return nil
 }
-
-type Img struct {
-	*os.File
-}
-
-func (img *Img) Size() (int64, error) {
-	fi, err := img.Stat()
-	if err != nil {
-		return 0, err
-	}
-	return fi.Size(), nil
-}
-
-type Ref[T any] struct {
-	img  *Img
-	addr int64
-	data T
-}
-
-func (r *Ref[T]) Read() error {
-	size, err := binstruct.Size(r.data)
-	if err != nil {
-		return err
-	}
-	buf := make([]byte, size)
-	if _, err := r.img.ReadAt(buf, r.addr); err != nil {
-		return err
-	}
-	return binstruct.Unmarshal(buf, &r.data)
-}
-
-func (img *Img) Superblocks() ([]Ref[Superblock], error) {
-	const superblockSize = 0x1000
-
-	var superblockAddrs = []int64{
-		0x00_0001_0000, // 64KiB
-		0x00_0400_0000, // 64MiB
-		0x40_0000_0000, // 256GiB
-	}
-
-	sz, err := img.Size()
-	if err != nil {
-		return nil, err
-	}
-
-	var ret []Ref[Superblock]
-	for i, addr := range superblockAddrs {
-		if addr+superblockSize <= sz {
-			superblock := Ref[Superblock]{
-				img:  img,
-				addr: addr,
-			}
-			if err := superblock.Read(); err != nil {
-				return nil, fmt.Errorf("superblock %d: %w", i, err)
-			}
-			ret = append(ret, superblock)
-		}
-	}
-	if len(ret) == 0 {
-		return nil, fmt.Errorf("no superblocks")
-	}
-	return ret, nil
-}
diff --git a/cmd/btrfs-dbg/types.go b/cmd/btrfs-dbg/types.go
deleted file mode 100644
index 3cd348d..0000000
--- a/cmd/btrfs-dbg/types.go
+++ /dev/null
@@ -1,156 +0,0 @@
-package main
-
-import (
-	"encoding/binary"
-	"encoding/hex"
-	"hash/crc32"
-	"strings"
-	"time"
-
-	"lukeshu.com/btrfs-tools/pkg/binstruct"
-)
-
-type (
-	PhysicalAddr int64
-	LogicalAddr  int64
-	ObjID        int64
-	CSum         [0x20]byte
-	UUID         [16]byte
-)
-
-func (uuid UUID) String() string {
-	str := hex.EncodeToString(uuid[:])
-	return strings.Join([]string{
-		str[:8],
-		str[8:12],
-		str[12:16],
-		str[16:20],
-		str[20:32],
-	}, "-")
-}
-
-func crc32c(data []byte) CSum {
-	sum := crc32.Update(0xFFFFFFFF, crc32.MakeTable(0x1EDC6F41), data)
-	var buf CSum
-	binary.LittleEndian.PutUint32(buf[:], sum)
-	return buf
-}
-
-type Key struct {
-	ObjectID      ObjID  `bin:"off=0, siz=8, desc=Object ID. Each tree has its own set of Object IDs."`
-	ItemType      uint8  `bin:"off=8, siz=1, desc=Item type."`
-	Offset        uint64 `bin:"off=9, siz=8, desc=Offset. The meaning depends on the item type."`
-	binstruct.End `bin:"off=11"`
-}
-
-type Time struct {
-	Sec           int64  `bin:"off=0, siz=8, desc=Number of seconds since 1970-01-01T00:00:00Z."`
-	NSec          uint64 `bin:"off=8, siz=4, desc=Number of nanoseconds since the beginning of the second."`
-	binstruct.End `bin:"off=c"`
-}
-
-func (t Time) ToStd() time.Time {
-	return time.Unix(t.Sec, int64(t.NSec))
-}
-
-type Superblock struct {
-	Checksum   CSum         `bin:"off=0,  siz=20, desc=Checksum of everything past this field (from 20 to 1000)"`
-	FSUUID     UUID         `bin:"off=20, siz=10, desc=FS UUID"`
-	Self       PhysicalAddr `bin:"off=30, siz=8,  desc=physical address of this block (different for mirrors)"`
-	Flags      uint64       `bin:"off=38, siz=8,  desc=flags"`
-	Magic      [8]byte      `bin:"off=40, siz=8,  desc=magic ('_BHRfS_M')"`
-	Generation uint64       `bin:"off=48, siz=8,  desc=generation"`
-
-	RootTree  LogicalAddr `bin:"off=50, siz=8,  desc=logical address of the root tree root"`
-	ChunkTree LogicalAddr `bin:"off=58, siz=8,  desc=logical address of the chunk tree root"`
-	LogTree   LogicalAddr `bin:"off=60, siz=8,  desc=logical address of the log tree root"`
-
-	LogRootTransID  uint64 `bin:"off=68, siz=8, desc=log_root_transid"`
-	TotalBytes      uint64 `bin:"off=70, siz=8, desc=total_bytes"`
-	BytesUsed       uint64 `bin:"off=78, siz=8, desc=bytes_used"`
-	RootDirObjectID uint64 `bin:"off=80, siz=8, desc=root_dir_objectid (usually 6)"`
-	NumDevices      uint64 `bin:"off=88, siz=8, desc=num_devices"`
-
-	SectorSize        uint32 `bin:"off=90, siz=4, desc=sectorsize"`
-	NodeSize          uint32 `bin:"off=94, siz=4, desc=nodesize"`
-	LeafSize          uint32 `bin:"off=98, siz=4, desc=leafsize"`
-	StripeSize        uint32 `bin:"off=9c, siz=4, desc=stripesize"`
-	SysChunkArraySize uint32 `bin:"off=a0, siz=4, desc=sys_chunk_array_size"`
-
-	ChunkRootGeneration uint64 `bin:"off=a4, siz=8, desc=chunk_root_generation"`
-	CompatFlags         uint64 `bin:"off=ac, siz=8, desc=compat_flags"`
-	CompatROFlags       uint64 `bin:"off=b4, siz=8, desc=compat_ro_flags - only implementations that support the flags can write to the filesystem"`
-	IncompatFlags       uint64 `bin:"off=bc, siz=8, desc=incompat_flags - only implementations that support the flags can use the filesystem"`
-	ChecksumType        uint16 `bin:"off=c4, siz=2, desc=csum_type - Btrfs currently uses the CRC32c little-endian hash function with seed -1."`
-
-	RootLevel  uint8 `bin:"off=c6, siz=1, desc=root_level"`
-	ChunkLevel uint8 `bin:"off=c7, siz=1, desc=chunk_root_level"`
-	LogLevel   uint8 `bin:"off=c8, siz=1, desc=log_root_level"`
-
-	DevItem            DevItem     `bin:"off=c9,  siz=62,  desc=DEV_ITEM data for this device"`
-	Label              [0x100]byte `bin:"off=12b, siz=100, desc=label (may not contain '/' or '\\')"`
-	CacheGeneration    uint64      `bin:"off=22b, siz=8,   desc=cache_generation"`
-	UUIDTreeGeneration uint64      `bin:"off=233, siz=8,   desc=uuid_tree_generation"`
-
-	Reserved [0xf0]byte `bin:"off=23b, siz=f0,  desc=reserved /* future expansion */"`
-
-	TODOSysChunkArray [0x800]byte `bin:"off=32b, siz=800, desc=sys_chunk_array:(n bytes valid) Contains (KEY . CHUNK_ITEM) pairs for all SYSTEM chunks. This is needed to bootstrap the mapping from logical addresses to physical. "`
-	TODOSuperRoots    [0x2a0]byte `bin:"off=b2b, siz=2a0, desc=Contain super_roots (4 btrfs_root_backup)"`
-
-	Unused [0x235]byte `bin:"off=dcb, siz=235, desc=current unused"`
-
-	binstruct.End `bin:"off=1000"`
-}
-
-func (sb Superblock) CalculateChecksum() (CSum, error) {
-	data, err := binstruct.Marshal(sb)
-	if err != nil {
-		return CSum{}, err
-	}
-	return crc32c(data[0x20:]), nil
-}
-
-type DevItem struct {
-	DeviceID uint64 `bin:"off=0,    siz=8,  desc=device id"`
-
-	NumBytes     uint64 `bin:"off=8,    siz=8,  desc=number of bytes"`
-	NumBytesUsed uint64 `bin:"off=10,   siz=8,  desc=number of bytes used"`
-
-	IOOptimalAlign uint32 `bin:"off=18,   siz=4,  desc=optimal I/O align"`
-	IOOptimalWidth uint32 `bin:"off=1c,   siz=4,  desc=optimal I/O width"`
-	IOMinSize      uint32 `bin:"off=20,   siz=4,  desc=minimal I/O size (sector size)"`
-
-	Type        uint64 `bin:"off=24,   siz=8,  desc=type"`
-	Generation  uint64 `bin:"off=2c,   siz=8,  desc=generation"`
-	StartOffset uint64 `bin:"off=34,   siz=8,  desc=start offset"`
-	DevGroup    uint32 `bin:"off=3c,   siz=4,  desc=dev group"`
-	SeekSpeed   uint8  `bin:"off=40,   siz=1,  desc=seek speed"`
-	Bandwidth   uint8  `bin:"off=41,   siz=1,  desc=bandwidth"`
-
-	DevUUID UUID `bin:"off=42,   siz=10,         desc=device UUID"`
-	FSUUID  UUID `bin:"off=52,   siz=10,         desc=FS UUID"`
-
-	binstruct.End `bin:"off=62"`
-}
-
-type ChunkItem struct {
-	// Maps logical address to physical.
-	Size           uint64 `bin:"off=0,  siz=8, desc=size of chunk (bytes)"`
-	Root           ObjID  `bin:"off=8,  siz=8, desc=root referencing this chunk (2)"`
-	StripeLen      uint64 `bin:"off=10, siz=8, desc=stripe length"`
-	Type           uint64 `bin:"off=18, siz=8, desc=type (same as flags for block group?)"`
-	IOOptimalAlign uint32 `bin:"off=20, siz=4, desc=optimal io alignment"`
-	IOOptimalWidth uint32 `bin:"off=24, siz=4, desc=optimal io width"`
-	IoMinSize      uint32 `bin:"off=28, siz=4, desc=minimal io size (sector size)"`
-	NumStripes     uint16 `bin:"off=2c, siz=2, desc=number of stripes"`
-	SubStripes     uint16 `bin:"off=2e, siz=2, desc=sub stripes"`
-	binstruct.End  `bin:"off=30"`
-}
-
-type ChunkItemStripe struct {
-	// Stripes follow (for each number of stripes):
-	DeviceID      ObjID  `bin:"off=0,  siz=8,  desc=device id"`
-	Offset        uint64 `bin:"off=8,  siz=8,  desc=offset"`
-	DeviceUUID    UUID   `bin:"off=10, siz=10, desc=device UUID"`
-	binstruct.End `bin:"off=20"`
-}