mirror of
https://github.com/golang/go
synced 2024-09-30 00:14:36 -06:00
archive/tar: forbid NUL character in string fields
USTAR and GNU strings are NUL-terminated. Thus, we should never allow the NUL terminator, otherwise we will lose data round-trip. Relevant specification text: <<< The fields magic, uname, and gname are character strings each terminated by a NUL character. >>> Technically, PAX keys and values should be UTF-8, but the observance of invalid files in the wild causes us to be more liberal. <<< The <length> field, <blank>, <equals-sign>, and <newline> shown shall be limited to the portable character set, as encoded in UTF-8. >>> Thus, we only reject NULs in PAX keys, and NULs for PAX values representing the USTAR string fields (i.e., path, linkpath, uname, gname). These are treated more strictly because they represent strings that are typically represented as C-strings on POSIX systems. Change-Id: I305b794d9d966faad852ff660bd0b3b0964e52bf Reviewed-on: https://go-review.googlesource.com/14724 Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com> Reviewed-by: Ian Lance Taylor <iant@golang.org>
This commit is contained in:
parent
c592c05745
commit
019d8a07e1
@ -335,6 +335,34 @@ func TestReader(t *testing.T) {
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ModTime: time.Unix(0, 0),
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Typeflag: '2',
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}},
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}, {
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// Both BSD and GNU tar truncate long names at first NUL even
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// if there is data following that NUL character.
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// This is reasonable as GNU long names are C-strings.
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file: "testdata/gnu-long-nul.tar",
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headers: []*Header{{
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Name: "0123456789",
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Mode: 0644,
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Uid: 1000,
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Gid: 1000,
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ModTime: time.Unix(1486082191, 0),
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Typeflag: '0',
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Uname: "rawr",
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Gname: "dsnet",
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}},
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}, {
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// BSD tar v3.1.2 and GNU tar v1.27.1 both rejects PAX records
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// with NULs in the key.
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file: "testdata/pax-nul-xattrs.tar",
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err: ErrHeader,
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}, {
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// BSD tar v3.1.2 rejects a PAX path with NUL in the value, while
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// GNU tar v1.27.1 simply truncates at first NUL.
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// We emulate the behavior of BSD since it is strange doing NUL
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// truncations since PAX records are length-prefix strings instead
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// of NUL-terminated C-strings.
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file: "testdata/pax-nul-path.tar",
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err: ErrHeader,
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}, {
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file: "testdata/neg-size.tar",
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err: ErrHeader,
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@ -358,76 +386,71 @@ func TestReader(t *testing.T) {
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}},
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}}
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for i, v := range vectors {
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f, err := os.Open(v.file)
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if err != nil {
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t.Errorf("file %s, test %d: unexpected error: %v", v.file, i, err)
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continue
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}
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defer f.Close()
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// Capture all headers and checksums.
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var (
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tr = NewReader(f)
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hdrs []*Header
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chksums []string
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rdbuf = make([]byte, 8)
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)
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for {
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var hdr *Header
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hdr, err = tr.Next()
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for _, v := range vectors {
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t.Run(path.Base(v.file), func(t *testing.T) {
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f, err := os.Open(v.file)
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if err != nil {
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if err == io.EOF {
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err = nil // Expected error
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t.Fatalf("unexpected error: %v", err)
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}
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defer f.Close()
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// Capture all headers and checksums.
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var (
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tr = NewReader(f)
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hdrs []*Header
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chksums []string
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rdbuf = make([]byte, 8)
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)
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for {
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var hdr *Header
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hdr, err = tr.Next()
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if err != nil {
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if err == io.EOF {
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err = nil // Expected error
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}
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break
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}
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break
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}
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hdrs = append(hdrs, hdr)
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hdrs = append(hdrs, hdr)
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if v.chksums == nil {
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continue
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if v.chksums == nil {
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continue
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}
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h := md5.New()
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_, err = io.CopyBuffer(h, tr, rdbuf) // Effectively an incremental read
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if err != nil {
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break
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}
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chksums = append(chksums, fmt.Sprintf("%x", h.Sum(nil)))
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}
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h := md5.New()
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_, err = io.CopyBuffer(h, tr, rdbuf) // Effectively an incremental read
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if err != nil {
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break
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}
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chksums = append(chksums, fmt.Sprintf("%x", h.Sum(nil)))
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}
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for j, hdr := range hdrs {
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if j >= len(v.headers) {
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t.Errorf("file %s, test %d, entry %d: unexpected header:\ngot %+v",
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v.file, i, j, *hdr)
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continue
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for i, hdr := range hdrs {
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if i >= len(v.headers) {
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t.Fatalf("entry %d: unexpected header:\ngot %+v", i, *hdr)
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continue
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}
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if !reflect.DeepEqual(*hdr, *v.headers[i]) {
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t.Fatalf("entry %d: incorrect header:\ngot %+v\nwant %+v", i, *hdr, *v.headers[i])
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}
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}
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if !reflect.DeepEqual(*hdr, *v.headers[j]) {
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t.Errorf("file %s, test %d, entry %d: incorrect header:\ngot %+v\nwant %+v",
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v.file, i, j, *hdr, *v.headers[j])
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if len(hdrs) != len(v.headers) {
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t.Fatalf("got %d headers, want %d headers", len(hdrs), len(v.headers))
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}
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}
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if len(hdrs) != len(v.headers) {
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t.Errorf("file %s, test %d: got %d headers, want %d headers",
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v.file, i, len(hdrs), len(v.headers))
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}
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for j, sum := range chksums {
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if j >= len(v.chksums) {
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t.Errorf("file %s, test %d, entry %d: unexpected sum: got %s",
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v.file, i, j, sum)
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continue
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for i, sum := range chksums {
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if i >= len(v.chksums) {
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t.Fatalf("entry %d: unexpected sum: got %s", i, sum)
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continue
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}
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if sum != v.chksums[i] {
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t.Fatalf("entry %d: incorrect checksum: got %s, want %s", i, sum, v.chksums[i])
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}
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}
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if sum != v.chksums[j] {
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t.Errorf("file %s, test %d, entry %d: incorrect checksum: got %s, want %s",
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v.file, i, j, sum, v.chksums[j])
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}
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}
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if err != v.err {
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t.Errorf("file %s, test %d: unexpected error: got %v, want %v",
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v.file, i, err, v.err)
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}
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f.Close()
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if err != v.err {
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t.Fatalf("unexpected error: got %v, want %v", err, v.err)
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}
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f.Close()
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})
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}
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}
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@ -12,22 +12,25 @@ import (
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"time"
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)
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// isASCII reports whether the input is an ASCII C-style string.
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func isASCII(s string) bool {
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for _, c := range s {
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if c >= 0x80 {
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if c >= 0x80 || c == 0x00 {
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return false
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}
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}
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return true
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}
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// toASCII converts the input to an ASCII C-style string.
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// This a best effort conversion, so invalid characters are dropped.
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func toASCII(s string) string {
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if isASCII(s) {
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return s
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}
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var buf bytes.Buffer
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for _, c := range s {
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if c < 0x80 {
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if c < 0x80 && c != 0x00 {
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buf.WriteByte(byte(c))
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}
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}
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@ -232,12 +235,21 @@ func parsePAXRecord(s string) (k, v, r string, err error) {
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if eq == -1 {
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return "", "", s, ErrHeader
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}
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return rec[:eq], rec[eq+1:], rem, nil
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k, v = rec[:eq], rec[eq+1:]
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if !validPAXRecord(k, v) {
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return "", "", s, ErrHeader
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}
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return k, v, rem, nil
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}
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// formatPAXRecord formats a single PAX record, prefixing it with the
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// appropriate length.
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func formatPAXRecord(k, v string) string {
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func formatPAXRecord(k, v string) (string, error) {
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if !validPAXRecord(k, v) {
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return "", ErrHeader
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}
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const padding = 3 // Extra padding for ' ', '=', and '\n'
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size := len(k) + len(v) + padding
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size += len(strconv.Itoa(size))
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@ -248,5 +260,19 @@ func formatPAXRecord(k, v string) string {
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size = len(record)
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record = fmt.Sprintf("%d %s=%s\n", size, k, v)
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}
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return record
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return record, nil
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}
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// validPAXRecord reports whether the key-value pair is valid.
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// Keys and values should be UTF-8, but the number of bad writers out there
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// forces us to be a more liberal.
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// Thus, we only reject all keys with NUL, and only reject NULs in values
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// for the PAX version of the USTAR string fields.
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func validPAXRecord(k, v string) bool {
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switch k {
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case paxPath, paxLinkpath, paxUname, paxGname:
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return strings.IndexByte(v, 0) < 0
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default:
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return strings.IndexByte(k, 0) < 0
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}
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}
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@ -256,7 +256,7 @@ func TestParsePAXRecord(t *testing.T) {
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{"18 foo=b=\nar=\n==\x00\n", "", "foo", "b=\nar=\n==\x00", true},
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{"27 foo=hello9 foo=ba\nworld\n", "", "foo", "hello9 foo=ba\nworld", true},
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{"27 ☺☻☹=日a本b語ç\nmeow mix", "meow mix", "☺☻☹", "日a本b語ç", true},
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{"17 \x00hello=\x00world\n", "", "\x00hello", "\x00world", true},
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{"17 \x00hello=\x00world\n", "17 \x00hello=\x00world\n", "", "", false},
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{"1 k=1\n", "1 k=1\n", "", "", false},
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{"6 k~1\n", "6 k~1\n", "", "", false},
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{"6_k=1\n", "6_k=1\n", "", "", false},
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@ -296,21 +296,33 @@ func TestFormatPAXRecord(t *testing.T) {
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inKey string
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inVal string
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want string
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ok bool
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}{
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{"k", "v", "6 k=v\n"},
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{"path", "/etc/hosts", "19 path=/etc/hosts\n"},
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{"path", longName, "210 path=" + longName + "\n"},
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{"path", medName, "110 path=" + medName + "\n"},
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{"foo", "ba", "9 foo=ba\n"},
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{"foo", "bar", "11 foo=bar\n"},
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{"foo", "b=\nar=\n==\x00", "18 foo=b=\nar=\n==\x00\n"},
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{"foo", "hello9 foo=ba\nworld", "27 foo=hello9 foo=ba\nworld\n"},
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{"☺☻☹", "日a本b語ç", "27 ☺☻☹=日a本b語ç\n"},
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{"\x00hello", "\x00world", "17 \x00hello=\x00world\n"},
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{"k", "v", "6 k=v\n", true},
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{"path", "/etc/hosts", "19 path=/etc/hosts\n", true},
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{"path", longName, "210 path=" + longName + "\n", true},
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{"path", medName, "110 path=" + medName + "\n", true},
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{"foo", "ba", "9 foo=ba\n", true},
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{"foo", "bar", "11 foo=bar\n", true},
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{"foo", "b=\nar=\n==\x00", "18 foo=b=\nar=\n==\x00\n", true},
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{"foo", "hello9 foo=ba\nworld", "27 foo=hello9 foo=ba\nworld\n", true},
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{"☺☻☹", "日a本b語ç", "27 ☺☻☹=日a本b語ç\n", true},
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{"xhello", "\x00world", "17 xhello=\x00world\n", true},
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{"path", "null\x00", "", false},
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{"null\x00", "value", "", false},
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{paxXattr + "key", "null\x00", "26 SCHILY.xattr.key=null\x00\n", true},
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}
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for _, v := range vectors {
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got := formatPAXRecord(v.inKey, v.inVal)
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got, err := formatPAXRecord(v.inKey, v.inVal)
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ok := (err == nil)
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if ok != v.ok {
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if v.ok {
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t.Errorf("formatPAXRecord(%q, %q): got format failure, want success", v.inKey, v.inVal)
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} else {
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t.Errorf("formatPAXRecord(%q, %q): got format success, want failure", v.inKey, v.inVal)
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}
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}
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if got != v.want {
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t.Errorf("formatPAXRecord(%q, %q): got %q, want %q",
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v.inKey, v.inVal, got, v.want)
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BIN
src/archive/tar/testdata/gnu-long-nul.tar
vendored
Normal file
BIN
src/archive/tar/testdata/gnu-long-nul.tar
vendored
Normal file
Binary file not shown.
BIN
src/archive/tar/testdata/pax-nul-path.tar
vendored
Normal file
BIN
src/archive/tar/testdata/pax-nul-path.tar
vendored
Normal file
Binary file not shown.
BIN
src/archive/tar/testdata/pax-nul-xattrs.tar
vendored
Normal file
BIN
src/archive/tar/testdata/pax-nul-xattrs.tar
vendored
Normal file
Binary file not shown.
@ -308,7 +308,11 @@ func (tw *Writer) writePAXHeader(hdr *Header, paxHeaders map[string]string) erro
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sort.Strings(keys)
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for _, k := range keys {
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fmt.Fprint(&buf, formatPAXRecord(k, paxHeaders[k]))
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rec, err := formatPAXRecord(k, paxHeaders[k])
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if err != nil {
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return err
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}
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fmt.Fprint(&buf, rec)
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}
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ext.Size = int64(len(buf.Bytes()))
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@ -10,6 +10,7 @@ import (
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"io"
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"io/ioutil"
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"os"
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"path"
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"reflect"
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"sort"
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"strings"
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@ -51,6 +52,7 @@ func TestWriter(t *testing.T) {
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vectors := []struct {
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file string // filename of expected output
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entries []*entry
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err error // expected error on WriteHeader
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}{{
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// The writer test file was produced with this command:
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// tar (GNU tar) 1.26
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@ -200,44 +202,57 @@ func TestWriter(t *testing.T) {
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},
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// no contents
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}},
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}, {
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entries: []*entry{{
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header: &Header{
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Name: "bad-null.txt",
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Typeflag: '0',
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Xattrs: map[string]string{"null\x00null\x00": "fizzbuzz"},
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},
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}},
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err: ErrHeader,
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}, {
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entries: []*entry{{
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header: &Header{
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Name: "null\x00.txt",
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Typeflag: '0',
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},
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}},
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err: ErrHeader,
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}}
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testLoop:
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for i, v := range vectors {
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expected, err := ioutil.ReadFile(v.file)
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if err != nil {
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t.Errorf("test %d: Unexpected error: %v", i, err)
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continue
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}
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for _, v := range vectors {
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t.Run(path.Base(v.file), func(t *testing.T) {
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buf := new(bytes.Buffer)
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tw := NewWriter(iotest.TruncateWriter(buf, 4<<10)) // only catch the first 4 KB
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canFail := false
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for i, entry := range v.entries {
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canFail = canFail || entry.header.Size > 1<<10 || v.err != nil
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buf := new(bytes.Buffer)
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tw := NewWriter(iotest.TruncateWriter(buf, 4<<10)) // only catch the first 4 KB
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big := false
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for j, entry := range v.entries {
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big = big || entry.header.Size > 1<<10
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if err := tw.WriteHeader(entry.header); err != nil {
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t.Errorf("test %d, entry %d: Failed writing header: %v", i, j, err)
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continue testLoop
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err := tw.WriteHeader(entry.header)
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if err != v.err {
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t.Fatalf("entry %d: WriteHeader() = %v, want %v", i, err, v.err)
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}
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if _, err := io.WriteString(tw, entry.contents); err != nil {
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t.Fatalf("entry %d: WriteString() = %v, want nil", i, err)
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}
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}
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if _, err := io.WriteString(tw, entry.contents); err != nil {
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t.Errorf("test %d, entry %d: Failed writing contents: %v", i, j, err)
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continue testLoop
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// Only interested in Close failures for the small tests.
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if err := tw.Close(); err != nil && !canFail {
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t.Fatalf("Close() = %v, want nil", err)
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}
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}
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// Only interested in Close failures for the small tests.
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if err := tw.Close(); err != nil && !big {
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t.Errorf("test %d: Failed closing archive: %v", i, err)
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continue testLoop
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}
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|
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actual := buf.Bytes()
|
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if !bytes.Equal(expected, actual) {
|
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t.Errorf("test %d: Incorrect result: (-=expected, +=actual)\n%v",
|
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i, bytediff(expected, actual))
|
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}
|
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if testing.Short() { // The second test is expensive.
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break
|
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}
|
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if v.file != "" {
|
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want, err := ioutil.ReadFile(v.file)
|
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if err != nil {
|
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t.Fatalf("ReadFile() = %v, want nil", err)
|
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}
|
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got := buf.Bytes()
|
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if !bytes.Equal(want, got) {
|
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t.Fatalf("incorrect result: (-=want, +=got)\n%v", bytediff(want, got))
|
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}
|
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}
|
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})
|
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}
|
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}
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|
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Reference in New Issue
Block a user