Commit 730db0af authored by David Thomas's avatar David Thomas Committed by Russ Cox

archive/tar: add support for GNU sparse files.

Supports all the current GNU tar sparse formats, including the
old GNU format and the GNU PAX format versions 0.0, 0.1, and 1.0.
Fixes #3864.

LGTM=rsc
R=golang-codereviews, dave, gobot, dsymonds, rsc
CC=golang-codereviews
https://golang.org/cl/64740043
parent dd9c4034
......@@ -38,6 +38,7 @@ const (
TypeXGlobalHeader = 'g' // global extended header
TypeGNULongName = 'L' // Next file has a long name
TypeGNULongLink = 'K' // Next file symlinks to a file w/ a long name
TypeGNUSparse = 'S' // sparse file
)
// A Header represents a single header in a tar archive.
......
This diff is collapsed.
......@@ -9,6 +9,7 @@ import (
"crypto/md5"
"fmt"
"io"
"io/ioutil"
"os"
"reflect"
"strings"
......@@ -54,8 +55,92 @@ var gnuTarTest = &untarTest{
},
}
var sparseTarTest = &untarTest{
file: "testdata/sparse-formats.tar",
headers: []*Header{
{
Name: "sparse-gnu",
Mode: 420,
Uid: 1000,
Gid: 1000,
Size: 200,
ModTime: time.Unix(1392395740, 0),
Typeflag: 0x53,
Linkname: "",
Uname: "david",
Gname: "david",
Devmajor: 0,
Devminor: 0,
},
{
Name: "sparse-posix-0.0",
Mode: 420,
Uid: 1000,
Gid: 1000,
Size: 200,
ModTime: time.Unix(1392342187, 0),
Typeflag: 0x30,
Linkname: "",
Uname: "david",
Gname: "david",
Devmajor: 0,
Devminor: 0,
},
{
Name: "sparse-posix-0.1",
Mode: 420,
Uid: 1000,
Gid: 1000,
Size: 200,
ModTime: time.Unix(1392340456, 0),
Typeflag: 0x30,
Linkname: "",
Uname: "david",
Gname: "david",
Devmajor: 0,
Devminor: 0,
},
{
Name: "sparse-posix-1.0",
Mode: 420,
Uid: 1000,
Gid: 1000,
Size: 200,
ModTime: time.Unix(1392337404, 0),
Typeflag: 0x30,
Linkname: "",
Uname: "david",
Gname: "david",
Devmajor: 0,
Devminor: 0,
},
{
Name: "end",
Mode: 420,
Uid: 1000,
Gid: 1000,
Size: 4,
ModTime: time.Unix(1392398319, 0),
Typeflag: 0x30,
Linkname: "",
Uname: "david",
Gname: "david",
Devmajor: 0,
Devminor: 0,
},
},
cksums: []string{
"6f53234398c2449fe67c1812d993012f",
"6f53234398c2449fe67c1812d993012f",
"6f53234398c2449fe67c1812d993012f",
"6f53234398c2449fe67c1812d993012f",
"b0061974914468de549a2af8ced10316",
},
}
var untarTests = []*untarTest{
gnuTarTest,
sparseTarTest,
{
file: "testdata/star.tar",
headers: []*Header{
......@@ -423,3 +508,220 @@ func TestMergePAX(t *testing.T) {
t.Errorf("incorrect merge: got %+v, want %+v", hdr, want)
}
}
func TestSparseEndToEnd(t *testing.T) {
test := sparseTarTest
f, err := os.Open(test.file)
if err != nil {
t.Fatalf("Unexpected error: %v", err)
}
defer f.Close()
tr := NewReader(f)
headers := test.headers
cksums := test.cksums
nread := 0
// loop over all files
for ; ; nread++ {
hdr, err := tr.Next()
if hdr == nil || err == io.EOF {
break
}
// check the header
if !reflect.DeepEqual(*hdr, *headers[nread]) {
t.Errorf("Incorrect header:\nhave %+v\nwant %+v",
*hdr, headers[nread])
}
// read and checksum the file data
h := md5.New()
_, err = io.Copy(h, tr)
if err != nil {
t.Fatalf("Unexpected error: %v", err)
}
// verify checksum
have := fmt.Sprintf("%x", h.Sum(nil))
want := cksums[nread]
if want != have {
t.Errorf("Bad checksum on file %s:\nhave %+v\nwant %+v", hdr.Name, have, want)
}
}
if nread != len(headers) {
t.Errorf("Didn't process all files\nexpected: %d\nprocessed %d\n", len(headers), nread)
}
}
type sparseFileReadTest struct {
sparseData []byte
sparseMap []sparseEntry
realSize int64
expected []byte
}
var sparseFileReadTests = []sparseFileReadTest{
{
sparseData: []byte("abcde"),
sparseMap: []sparseEntry{
{offset: 0, numBytes: 2},
{offset: 5, numBytes: 3},
},
realSize: 8,
expected: []byte("ab\x00\x00\x00cde"),
},
{
sparseData: []byte("abcde"),
sparseMap: []sparseEntry{
{offset: 0, numBytes: 2},
{offset: 5, numBytes: 3},
},
realSize: 10,
expected: []byte("ab\x00\x00\x00cde\x00\x00"),
},
{
sparseData: []byte("abcde"),
sparseMap: []sparseEntry{
{offset: 1, numBytes: 3},
{offset: 6, numBytes: 2},
},
realSize: 8,
expected: []byte("\x00abc\x00\x00de"),
},
{
sparseData: []byte("abcde"),
sparseMap: []sparseEntry{
{offset: 1, numBytes: 3},
{offset: 6, numBytes: 2},
},
realSize: 10,
expected: []byte("\x00abc\x00\x00de\x00\x00"),
},
{
sparseData: []byte(""),
sparseMap: nil,
realSize: 2,
expected: []byte("\x00\x00"),
},
}
func TestSparseFileReader(t *testing.T) {
for i, test := range sparseFileReadTests {
r := bytes.NewReader(test.sparseData)
nb := int64(r.Len())
sfr := &sparseFileReader{
rfr: &regFileReader{r: r, nb: nb},
sp: test.sparseMap,
pos: 0,
tot: test.realSize,
}
if sfr.numBytes() != nb {
t.Errorf("test %d: Before reading, sfr.numBytes() = %d, want %d", i, sfr.numBytes, nb)
}
buf, err := ioutil.ReadAll(sfr)
if err != nil {
t.Errorf("test %d: Unexpected error: %v", i, err)
}
if e := test.expected; !bytes.Equal(buf, e) {
t.Errorf("test %d: Contents = %v, want %v", i, buf, e)
}
if sfr.numBytes() != 0 {
t.Errorf("test %d: After draining the reader, numBytes() was nonzero", i)
}
}
}
func TestSparseIncrementalRead(t *testing.T) {
sparseMap := []sparseEntry{{10, 2}}
sparseData := []byte("Go")
expected := "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00Go\x00\x00\x00\x00\x00\x00\x00\x00"
r := bytes.NewReader(sparseData)
nb := int64(r.Len())
sfr := &sparseFileReader{
rfr: &regFileReader{r: r, nb: nb},
sp: sparseMap,
pos: 0,
tot: int64(len(expected)),
}
// We'll read the data 6 bytes at a time, with a hole of size 10 at
// the beginning and one of size 8 at the end.
var outputBuf bytes.Buffer
buf := make([]byte, 6)
for {
n, err := sfr.Read(buf)
if err == io.EOF {
break
}
if err != nil {
t.Errorf("Read: unexpected error %v\n", err)
}
if n > 0 {
_, err := outputBuf.Write(buf[:n])
if err != nil {
t.Errorf("Write: unexpected error %v\n", err)
}
}
}
got := outputBuf.String()
if got != expected {
t.Errorf("Contents = %v, want %v", got, expected)
}
}
func TestReadGNUSparseMap0x1(t *testing.T) {
headers := map[string]string{
paxGNUSparseNumBlocks: "4",
paxGNUSparseMap: "0,5,10,5,20,5,30,5",
}
expected := []sparseEntry{
{offset: 0, numBytes: 5},
{offset: 10, numBytes: 5},
{offset: 20, numBytes: 5},
{offset: 30, numBytes: 5},
}
sp, err := readGNUSparseMap0x1(headers)
if err != nil {
t.Errorf("Unexpected error: %v", err)
}
if !reflect.DeepEqual(sp, expected) {
t.Errorf("Incorrect sparse map: got %v, wanted %v", sp, expected)
}
}
func TestReadGNUSparseMap1x0(t *testing.T) {
// This test uses lots of holes so the sparse header takes up more than two blocks
numEntries := 100
expected := make([]sparseEntry, 0, numEntries)
sparseMap := new(bytes.Buffer)
fmt.Fprintf(sparseMap, "%d\n", numEntries)
for i := 0; i < numEntries; i++ {
offset := int64(2048 * i)
numBytes := int64(1024)
expected = append(expected, sparseEntry{offset: offset, numBytes: numBytes})
fmt.Fprintf(sparseMap, "%d\n%d\n", offset, numBytes)
}
// Make the header the smallest multiple of blockSize that fits the sparseMap
headerBlocks := (sparseMap.Len() + blockSize - 1) / blockSize
bufLen := blockSize * headerBlocks
buf := make([]byte, bufLen)
copy(buf, sparseMap.Bytes())
// Get an reader to read the sparse map
r := bytes.NewReader(buf)
// Read the sparse map
sp, err := readGNUSparseMap1x0(r)
if err != nil {
t.Errorf("Unexpected error: %v", err)
}
if !reflect.DeepEqual(sp, expected) {
t.Errorf("Incorrect sparse map: got %v, wanted %v", sp, expected)
}
}
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