diff --git a/datareader.go b/datareader.go new file mode 100644 index 0000000..39af8cd --- /dev/null +++ b/datareader.go @@ -0,0 +1,141 @@ +package squashfs + +import ( + "bytes" + "errors" + "io" +) + +type DataReader struct { + r *Reader + offset int64 //offset relative to the beginning of the squash file + blocks []DataBlock + curBlock int //Which block in sizes is currently cached + curData []byte + curReadOffset int //offset relative to the currently cached data + readOffset int //offset relative to the beginning +} + +type DataBlock struct { + begOffset int64 //The offset relative to the beginning of the squash file. Makes it easier to seek to it. + size uint32 + compressed bool + uncompressedSize uint32 +} + +func NewDataBlockSize(raw uint32) (dbs DataBlock) { + dbs.compressed = raw&1<<24 != 1<<24 + dbs.size = raw &^ 1 << 24 + if !dbs.compressed { + dbs.uncompressedSize = dbs.size + } + return +} + +func (r *Reader) NewDataReader(offset int64, sizes []uint32) (*DataReader, error) { + var dr DataReader + dr.r = r + dr.offset = offset + for _, size := range sizes { + dr.blocks = append(dr.blocks, NewDataBlockSize(size)) + } + err := dr.readCurBlock() + if err != nil { + return nil, err + } + return &dr, nil +} + +func (d *DataReader) readNextBlock() error { + d.curBlock++ + if d.curBlock >= len(d.blocks) { + d.curBlock-- + return errors.New("Ran out of blocks") + } + err := d.readCurBlock() + if err != nil { + d.curBlock-- + d.readCurBlock() + return err + } + return nil +} + +func (d *DataReader) readCurBlock() error { + if d.blocks[d.curBlock].size == 0 { + d.curData = make([]byte, d.r.super.BlockSize) + d.blocks[d.curBlock].uncompressedSize = d.r.super.BlockSize + d.blocks[d.curBlock].begOffset = d.offset + return nil + } + sec := io.NewSectionReader(d.r.r, d.offset, int64(d.blocks[d.curBlock].size)) + if d.blocks[d.curBlock].compressed { + btys, err := d.r.decompressor.Decompress(sec) + if err != nil { + return err + } + d.blocks[d.curBlock].uncompressedSize = uint32(len(btys)) + d.curData = btys + d.blocks[d.curBlock].begOffset = d.offset + d.offset += int64(d.blocks[d.curBlock].size) + return nil + } + var buf bytes.Buffer + _, err := io.Copy(&buf, sec) + if err != nil { + return err + } + d.blocks[d.curBlock].begOffset = d.offset + d.offset += int64(d.blocks[d.curBlock].size) + return err +} + +func (d *DataReader) Read(p []byte) (int, error) { + if d.curReadOffset+len(p) < len(d.curData) { + for i := 0; i < len(p); i++ { + p[i] = d.curData[d.curReadOffset+i] + } + d.readOffset += len(p) + d.curReadOffset += len(p) + return len(p), nil + } + read := 0 + curRead := 0 + for read < len(p) { + if d.curReadOffset == len(d.curData) { + err := d.readNextBlock() + if err != nil { + d.readOffset += read + return read, err + } + curRead = 0 + } + for ; read < len(p); read++ { + curRead++ + if d.curReadOffset+curRead < len(d.curData) { + p[read] = d.curData[d.readOffset+curRead] + } else { + break + } + } + } + d.readOffset += read + if read != len(p) { + return read, errors.New("Didn't read enough data") + } + return read, nil +} + +func (d *DataReader) Seek(offset int64, whence int) (int, error) { + if whence == io.SeekStart { + d.readOffset = int(offset) + d.curReadOffset = int(offset) + + } + switch whence { + case io.SeekCurrent: + d.readOffset += int(offset) + d.curReadOffset += int(offset) + case io.SeekStart: + } +} diff --git a/fragment.go b/fragment.go index 868c294..a1f2d48 100644 --- a/fragment.go +++ b/fragment.go @@ -9,8 +9,9 @@ import ( ) type FragmentEntryRaw struct { - Start uint64 - Size uint32 + Start uint64 + Size uint32 + _unused uint32 } type FragmentEntry struct { @@ -20,10 +21,10 @@ type FragmentEntry struct { } //NewFragmentEntry reads a fragment entry from the given io.Reader. -func (r *Reader) NewFragmentEntry(rdr *io.Reader) (*FragmentEntry, error) { +func (r *Reader) NewFragmentEntry(rdr io.Reader) (*FragmentEntry, error) { var entry FragmentEntry var raw FragmentEntryRaw - err := binary.Read(*rdr, binary.LittleEndian, &raw) + err := binary.Read(rdr, binary.LittleEndian, &raw) if err != nil { return nil, err } @@ -33,16 +34,52 @@ func (r *Reader) NewFragmentEntry(rdr *io.Reader) (*FragmentEntry, error) { return &entry, nil } -//GetFragmentFromInode returns the fragment data for a given inode -func (r *Reader) GetFragmentFromInode(in *inode.Inode) ([]byte, error) { - if in.Type != inode.BasicFileType { - return nil, errors.New("Only basic file is supported right now") - } - bf := in.Info.(inode.BasicFile) +//GetFragmentDataFromInode returns the fragment data for a given inode. +//If the inode does not have a fragment, harmlessly returns an empty slice without an error. +func (r *Reader) GetFragmentDataFromInode(in *inode.Inode) ([]byte, error) { var size uint32 - if bf.Init.BlockStart == 0 { - size = bf.Init.Size + var fragIndex uint32 + var fragOffset uint32 + if in.Type == inode.BasicFileType { + bf := in.Info.(inode.BasicFile) + if !bf.Fragmented { + return make([]byte, 0), nil + } + if bf.Init.BlockStart == 0 { + size = bf.Init.Size + } else { + size = bf.BlockSizes[len(bf.BlockSizes)-1] + } + fragIndex = bf.Init.FragmentIndex + fragOffset = bf.Init.FragmentOffset + } else if in.Type == inode.ExtFileType { + bf := in.Info.(inode.ExtendedFile) + if !bf.Fragmented { + return make([]byte, 0), nil + } + if bf.Init.BlockStart == 0 { + size = bf.Init.Size + } else { + size = bf.BlockSizes[len(bf.BlockSizes)-1] + } + fragIndex = bf.Init.FragmentIndex + fragOffset = bf.Init.FragmentOffset } else { - size = bf.BlockSizes + return nil, errors.New("Inode type not supported") } + frag := r.fragEntries[fragIndex] + datRdr, err := r.NewDataReader(int64(frag.start), []uint32{frag.size}) + if err != nil { + return nil, err + } + _, err = datRdr.Seek(int64(fragOffset), io.SeekStart) + if err != nil { + return nil, err + } + tmp := make([]byte, size) + _, err = datRdr.Read(tmp) + if err != nil { + return nil, err + } + return tmp, nil } diff --git a/go.mod b/go.mod new file mode 100644 index 0000000..64e11a4 --- /dev/null +++ b/go.mod @@ -0,0 +1,5 @@ +module github.com/CalebQ42/GoSquashfs + +go 1.15 + +require github.com/CalebQ42/GoAppImage v0.4.0 diff --git a/go.sum b/go.sum new file mode 100644 index 0000000..d557baf --- /dev/null +++ b/go.sum @@ -0,0 +1,43 @@ +github.com/CalebQ42/GoAppImage v0.4.0 h1:aF+Y/vyo/RGhoyZEW1CMY6WyRWrZZO4ydsRFAtIGnaY= +github.com/CalebQ42/GoAppImage v0.4.0/go.mod h1:qHudJKAn/dlkNWNnH4h1YKXp29EZ7Bppsn7sNP2HuvU= +github.com/adrg/xdg v0.2.2 h1:A7ZHKRz5KGOLJX/bg7IPzStryhvCzAE1wX+KWawPiAo= +github.com/adrg/xdg v0.2.2/go.mod h1:7I2hH/IT30IsupOpKZ5ue7/qNi3CoKzD6tL3HwpaRMQ= +github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38= +github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c= +github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38= +github.com/google/go-cmp v0.4.0 h1:xsAVV57WRhGj6kEIi8ReJzQlHHqcBYCElAvkovg3B/4= +github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE= +github.com/gopherjs/gopherjs v0.0.0-20181017120253-0766667cb4d1 h1:EGx4pi6eqNxGaHF6qqu48+N2wcFQ5qg5FXgOdqsJ5d8= +github.com/gopherjs/gopherjs v0.0.0-20181017120253-0766667cb4d1/go.mod h1:wJfORRmW1u3UXTncJ5qlYoELFm8eSnnEO6hX4iZ3EWY= +github.com/jtolds/gls v4.20.0+incompatible h1:xdiiI2gbIgH/gLH7ADydsJ1uDOEzR8yvV7C0MuV77Wo= +github.com/jtolds/gls v4.20.0+incompatible/go.mod h1:QJZ7F/aHp+rZTRtaJ1ow/lLfFfVYBRgL+9YlvaHOwJU= +github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ= +github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE= +github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI= +github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e h1:fD57ERR4JtEqsWbfPhv4DMiApHyliiK5xCTNVSPiaAs= +github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e/go.mod h1:zD1mROLANZcx1PVRCS0qkT7pwLkGfwJo4zjcN/Tysno= +github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM= +github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4= +github.com/smartystreets/assertions v0.0.0-20180927180507-b2de0cb4f26d h1:zE9ykElWQ6/NYmHa3jpm/yHnI4xSofP+UP6SpjHcSeM= +github.com/smartystreets/assertions v0.0.0-20180927180507-b2de0cb4f26d/go.mod h1:OnSkiWE9lh6wB0YB77sQom3nweQdgAjqCqsofrRNTgc= +github.com/smartystreets/goconvey v1.6.4 h1:fv0U8FUIMPNf1L9lnHLvLhgicrIVChEkdzIKYqbNC9s= +github.com/smartystreets/goconvey v1.6.4/go.mod h1:syvi0/a8iFYH4r/RixwvyeAJjdLS9QV7WQ/tjFTllLA= +github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME= +github.com/stretchr/testify v1.6.1 h1:hDPOHmpOpP40lSULcqw7IrRb/u7w6RpDC9399XyoNd0= +github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg= +go.lsp.dev/uri v0.3.0 h1:KcZJmh6nFIBeJzTugn5JTU6OOyG0lDOo3R9KwTxTYbo= +go.lsp.dev/uri v0.3.0/go.mod h1:P5sbO1IQR+qySTWOCnhnK7phBx+W3zbLqSMDJNTw88I= +golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w= +golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg= +golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY= +golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ= +golang.org/x/tools v0.0.0-20190328211700-ab21143f2384/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs= +golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4= +golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0= +gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0= +gopkg.in/check.v1 v1.0.0-20200902074654-038fdea0a05b h1:QRR6H1YWRnHb4Y/HeNFCTJLFVxaq6wH4YuVdsUOr75U= +gopkg.in/check.v1 v1.0.0-20200902074654-038fdea0a05b/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0= +gopkg.in/ini.v1 v1.62.0 h1:duBzk771uxoUuOlyRLkHsygud9+5lrlGjdFBb4mSKDU= +gopkg.in/ini.v1 v1.62.0/go.mod h1:pNLf8WUiyNEtQjuu5G5vTm06TEv9tsIgeAvK8hOrP4k= +gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo= +gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM= diff --git a/internal/inode/inode.go b/internal/inode/inode.go index ad6cced..f586fe1 100644 --- a/internal/inode/inode.go +++ b/internal/inode/inode.go @@ -151,6 +151,7 @@ type ExtendedFileInit struct { type ExtendedFile struct { Init ExtendedFileInit BlockSizes []uint32 + Fragmented bool } //NewExtendedFile creates a new ExtendedFile @@ -160,6 +161,7 @@ func NewExtendedFile(rdr io.Reader, blockSize uint32) (ExtendedFile, error) { if err != nil { return inode, err } + inode.Fragmented = inode.Init.FragmentIndex != 0xFFFFFFFF blocks := inode.Init.Size / blockSize if inode.Init.Size%blockSize > 0 { blocks++ diff --git a/squashfsreader.go b/reader.go similarity index 84% rename from squashfsreader.go rename to reader.go index ef0b9f5..faaa836 100644 --- a/squashfsreader.go +++ b/reader.go @@ -7,7 +7,6 @@ import ( "io" "strings" - "github.com/CalebQ42/GoSquashfs/internal/directory" "github.com/CalebQ42/GoSquashfs/internal/inode" ) @@ -22,6 +21,9 @@ var ( ErrIncompatibleCompression = errors.New("Compression type unsupported") //ErrCompressorOptions is returned if compressor options is present. It's not currently supported. ErrCompressorOptions = errors.New("Compressor options is not currently supported") + //ErrFragmentTableIssues is returned if there's trouble reading the fragment table when creating a reader. + //When this is returned, the reader is still returned. + ErrFragmentTableIssues = errors.New("Trouble while reading the fragment table") ) //Reader processes and reads a squashfs archive. @@ -31,7 +33,7 @@ type Reader struct { super Superblock flags SuperblockFlags decompressor Decompressor - dirs []*directory.Directory + fragEntries []*FragmentEntry } //NewSquashfsReader returns a new squashfs.Reader from an io.ReaderAt @@ -56,6 +58,17 @@ func NewSquashfsReader(r io.ReaderAt) (*Reader, error) { //TODO: parse compressor options return nil, ErrCompressorOptions } + br, err := rdr.NewBlockReader(int64(rdr.super.FragTableStart)) + if err != nil { + return &rdr, err + } + for i := 0; i < int(rdr.super.FragCount); i++ { + entry, err := rdr.NewFragmentEntry(br) + if err != nil { + return &rdr, err + } + rdr.fragEntries = append(rdr.fragEntries, entry) + } return &rdr, nil } diff --git a/squash_test.go b/squash_test.go index 4fafc99..501819f 100644 --- a/squash_test.go +++ b/squash_test.go @@ -39,6 +39,23 @@ func TestMain(t *testing.T) { if err != nil { t.Fatal(err) } + i, err := rdr.GetInodeFromPath("code-oss.desktop") + if err != nil { + t.Fatal(err) + } + os.Remove(wd + "/testing/code-oss.desktop") + desk, err := os.Create(wd + "/testing/code-oss.desktop") + if err != nil { + t.Fatal(err) + } + btys, err := rdr.GetFragmentDataFromInode(i) + if err != nil { + t.Fatal(err) + } + _, err = desk.Write(btys) + if err != nil { + t.Fatal(err) + } t.Fatal("No problems here!") }