diff options
Diffstat (limited to 'vendor/github.com/vbatts/tar-split/archive/tar/common.go')
| -rw-r--r-- | vendor/github.com/vbatts/tar-split/archive/tar/common.go | 689 |
1 files changed, 536 insertions, 153 deletions
diff --git a/vendor/github.com/vbatts/tar-split/archive/tar/common.go b/vendor/github.com/vbatts/tar-split/archive/tar/common.go index 36f4e2398..dee9e47e4 100644 --- a/vendor/github.com/vbatts/tar-split/archive/tar/common.go +++ b/vendor/github.com/vbatts/tar-split/archive/tar/common.go @@ -3,70 +3,528 @@ // license that can be found in the LICENSE file. // Package tar implements access to tar archives. -// It aims to cover most of the variations, including those produced -// by GNU and BSD tars. // -// References: -// http://www.freebsd.org/cgi/man.cgi?query=tar&sektion=5 -// http://www.gnu.org/software/tar/manual/html_node/Standard.html -// http://pubs.opengroup.org/onlinepubs/9699919799/utilities/pax.html +// Tape archives (tar) are a file format for storing a sequence of files that +// can be read and written in a streaming manner. +// This package aims to cover most variations of the format, +// including those produced by GNU and BSD tar tools. package tar import ( - "bytes" "errors" "fmt" + "math" "os" "path" + "reflect" + "strconv" + "strings" "time" ) +// BUG: Use of the Uid and Gid fields in Header could overflow on 32-bit +// architectures. If a large value is encountered when decoding, the result +// stored in Header will be the truncated version. + +var ( + ErrHeader = errors.New("archive/tar: invalid tar header") + ErrWriteTooLong = errors.New("archive/tar: write too long") + ErrFieldTooLong = errors.New("archive/tar: header field too long") + ErrWriteAfterClose = errors.New("archive/tar: write after close") + errMissData = errors.New("archive/tar: sparse file references non-existent data") + errUnrefData = errors.New("archive/tar: sparse file contains unreferenced data") + errWriteHole = errors.New("archive/tar: write non-NUL byte in sparse hole") +) + +type headerError []string + +func (he headerError) Error() string { + const prefix = "archive/tar: cannot encode header" + var ss []string + for _, s := range he { + if s != "" { + ss = append(ss, s) + } + } + if len(ss) == 0 { + return prefix + } + return fmt.Sprintf("%s: %v", prefix, strings.Join(ss, "; and ")) +} + +// Type flags for Header.Typeflag. const ( - blockSize = 512 - - // Types - TypeReg = '0' // regular file - TypeRegA = '\x00' // regular file - TypeLink = '1' // hard link - TypeSymlink = '2' // symbolic link - TypeChar = '3' // character device node - TypeBlock = '4' // block device node - TypeDir = '5' // directory - TypeFifo = '6' // fifo node - TypeCont = '7' // reserved - TypeXHeader = 'x' // extended header - 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 + // Type '0' indicates a regular file. + TypeReg = '0' + TypeRegA = '\x00' // Deprecated: Use TypeReg instead. + + // Type '1' to '6' are header-only flags and may not have a data body. + TypeLink = '1' // Hard link + TypeSymlink = '2' // Symbolic link + TypeChar = '3' // Character device node + TypeBlock = '4' // Block device node + TypeDir = '5' // Directory + TypeFifo = '6' // FIFO node + + // Type '7' is reserved. + TypeCont = '7' + + // Type 'x' is used by the PAX format to store key-value records that + // are only relevant to the next file. + // This package transparently handles these types. + TypeXHeader = 'x' + + // Type 'g' is used by the PAX format to store key-value records that + // are relevant to all subsequent files. + // This package only supports parsing and composing such headers, + // but does not currently support persisting the global state across files. + TypeXGlobalHeader = 'g' + + // Type 'S' indicates a sparse file in the GNU format. + TypeGNUSparse = 'S' + + // Types 'L' and 'K' are used by the GNU format for a meta file + // used to store the path or link name for the next file. + // This package transparently handles these types. + TypeGNULongName = 'L' + TypeGNULongLink = 'K' ) +// Keywords for PAX extended header records. +const ( + paxNone = "" // Indicates that no PAX key is suitable + paxPath = "path" + paxLinkpath = "linkpath" + paxSize = "size" + paxUid = "uid" + paxGid = "gid" + paxUname = "uname" + paxGname = "gname" + paxMtime = "mtime" + paxAtime = "atime" + paxCtime = "ctime" // Removed from later revision of PAX spec, but was valid + paxCharset = "charset" // Currently unused + paxComment = "comment" // Currently unused + + paxSchilyXattr = "SCHILY.xattr." + + // Keywords for GNU sparse files in a PAX extended header. + paxGNUSparse = "GNU.sparse." + paxGNUSparseNumBlocks = "GNU.sparse.numblocks" + paxGNUSparseOffset = "GNU.sparse.offset" + paxGNUSparseNumBytes = "GNU.sparse.numbytes" + paxGNUSparseMap = "GNU.sparse.map" + paxGNUSparseName = "GNU.sparse.name" + paxGNUSparseMajor = "GNU.sparse.major" + paxGNUSparseMinor = "GNU.sparse.minor" + paxGNUSparseSize = "GNU.sparse.size" + paxGNUSparseRealSize = "GNU.sparse.realsize" +) + +// basicKeys is a set of the PAX keys for which we have built-in support. +// This does not contain "charset" or "comment", which are both PAX-specific, +// so adding them as first-class features of Header is unlikely. +// Users can use the PAXRecords field to set it themselves. +var basicKeys = map[string]bool{ + paxPath: true, paxLinkpath: true, paxSize: true, paxUid: true, paxGid: true, + paxUname: true, paxGname: true, paxMtime: true, paxAtime: true, paxCtime: true, +} + // A Header represents a single header in a tar archive. // Some fields may not be populated. +// +// For forward compatibility, users that retrieve a Header from Reader.Next, +// mutate it in some ways, and then pass it back to Writer.WriteHeader +// should do so by creating a new Header and copying the fields +// that they are interested in preserving. type Header struct { - Name string // name of header file entry - Mode int64 // permission and mode bits - Uid int // user id of owner - Gid int // group id of owner - Size int64 // length in bytes - ModTime time.Time // modified time - Typeflag byte // type of header entry - Linkname string // target name of link - Uname string // user name of owner - Gname string // group name of owner - Devmajor int64 // major number of character or block device - Devminor int64 // minor number of character or block device - AccessTime time.Time // access time - ChangeTime time.Time // status change time - Xattrs map[string]string + // Typeflag is the type of header entry. + // The zero value is automatically promoted to either TypeReg or TypeDir + // depending on the presence of a trailing slash in Name. + Typeflag byte + + Name string // Name of file entry + Linkname string // Target name of link (valid for TypeLink or TypeSymlink) + + Size int64 // Logical file size in bytes + Mode int64 // Permission and mode bits + Uid int // User ID of owner + Gid int // Group ID of owner + Uname string // User name of owner + Gname string // Group name of owner + + // If the Format is unspecified, then Writer.WriteHeader rounds ModTime + // to the nearest second and ignores the AccessTime and ChangeTime fields. + // + // To use AccessTime or ChangeTime, specify the Format as PAX or GNU. + // To use sub-second resolution, specify the Format as PAX. + ModTime time.Time // Modification time + AccessTime time.Time // Access time (requires either PAX or GNU support) + ChangeTime time.Time // Change time (requires either PAX or GNU support) + + Devmajor int64 // Major device number (valid for TypeChar or TypeBlock) + Devminor int64 // Minor device number (valid for TypeChar or TypeBlock) + + // Xattrs stores extended attributes as PAX records under the + // "SCHILY.xattr." namespace. + // + // The following are semantically equivalent: + // h.Xattrs[key] = value + // h.PAXRecords["SCHILY.xattr."+key] = value + // + // When Writer.WriteHeader is called, the contents of Xattrs will take + // precedence over those in PAXRecords. + // + // Deprecated: Use PAXRecords instead. + Xattrs map[string]string + + // PAXRecords is a map of PAX extended header records. + // + // User-defined records should have keys of the following form: + // VENDOR.keyword + // Where VENDOR is some namespace in all uppercase, and keyword may + // not contain the '=' character (e.g., "GOLANG.pkg.version"). + // The key and value should be non-empty UTF-8 strings. + // + // When Writer.WriteHeader is called, PAX records derived from the + // other fields in Header take precedence over PAXRecords. + PAXRecords map[string]string + + // Format specifies the format of the tar header. + // + // This is set by Reader.Next as a best-effort guess at the format. + // Since the Reader liberally reads some non-compliant files, + // it is possible for this to be FormatUnknown. + // + // If the format is unspecified when Writer.WriteHeader is called, + // then it uses the first format (in the order of USTAR, PAX, GNU) + // capable of encoding this Header (see Format). + Format Format } -// File name constants from the tar spec. -const ( - fileNameSize = 100 // Maximum number of bytes in a standard tar name. - fileNamePrefixSize = 155 // Maximum number of ustar extension bytes. +// sparseEntry represents a Length-sized fragment at Offset in the file. +type sparseEntry struct{ Offset, Length int64 } + +func (s sparseEntry) endOffset() int64 { return s.Offset + s.Length } + +// A sparse file can be represented as either a sparseDatas or a sparseHoles. +// As long as the total size is known, they are equivalent and one can be +// converted to the other form and back. The various tar formats with sparse +// file support represent sparse files in the sparseDatas form. That is, they +// specify the fragments in the file that has data, and treat everything else as +// having zero bytes. As such, the encoding and decoding logic in this package +// deals with sparseDatas. +// +// However, the external API uses sparseHoles instead of sparseDatas because the +// zero value of sparseHoles logically represents a normal file (i.e., there are +// no holes in it). On the other hand, the zero value of sparseDatas implies +// that the file has no data in it, which is rather odd. +// +// As an example, if the underlying raw file contains the 10-byte data: +// var compactFile = "abcdefgh" +// +// And the sparse map has the following entries: +// var spd sparseDatas = []sparseEntry{ +// {Offset: 2, Length: 5}, // Data fragment for 2..6 +// {Offset: 18, Length: 3}, // Data fragment for 18..20 +// } +// var sph sparseHoles = []sparseEntry{ +// {Offset: 0, Length: 2}, // Hole fragment for 0..1 +// {Offset: 7, Length: 11}, // Hole fragment for 7..17 +// {Offset: 21, Length: 4}, // Hole fragment for 21..24 +// } +// +// Then the content of the resulting sparse file with a Header.Size of 25 is: +// var sparseFile = "\x00"*2 + "abcde" + "\x00"*11 + "fgh" + "\x00"*4 +type ( + sparseDatas []sparseEntry + sparseHoles []sparseEntry ) +// validateSparseEntries reports whether sp is a valid sparse map. +// It does not matter whether sp represents data fragments or hole fragments. +func validateSparseEntries(sp []sparseEntry, size int64) bool { + // Validate all sparse entries. These are the same checks as performed by + // the BSD tar utility. + if size < 0 { + return false + } + var pre sparseEntry + for _, cur := range sp { + switch { + case cur.Offset < 0 || cur.Length < 0: + return false // Negative values are never okay + case cur.Offset > math.MaxInt64-cur.Length: + return false // Integer overflow with large length + case cur.endOffset() > size: + return false // Region extends beyond the actual size + case pre.endOffset() > cur.Offset: + return false // Regions cannot overlap and must be in order + } + pre = cur + } + return true +} + +// alignSparseEntries mutates src and returns dst where each fragment's +// starting offset is aligned up to the nearest block edge, and each +// ending offset is aligned down to the nearest block edge. +// +// Even though the Go tar Reader and the BSD tar utility can handle entries +// with arbitrary offsets and lengths, the GNU tar utility can only handle +// offsets and lengths that are multiples of blockSize. +func alignSparseEntries(src []sparseEntry, size int64) []sparseEntry { + dst := src[:0] + for _, s := range src { + pos, end := s.Offset, s.endOffset() + pos += blockPadding(+pos) // Round-up to nearest blockSize + if end != size { + end -= blockPadding(-end) // Round-down to nearest blockSize + } + if pos < end { + dst = append(dst, sparseEntry{Offset: pos, Length: end - pos}) + } + } + return dst +} + +// invertSparseEntries converts a sparse map from one form to the other. +// If the input is sparseHoles, then it will output sparseDatas and vice-versa. +// The input must have been already validated. +// +// This function mutates src and returns a normalized map where: +// * adjacent fragments are coalesced together +// * only the last fragment may be empty +// * the endOffset of the last fragment is the total size +func invertSparseEntries(src []sparseEntry, size int64) []sparseEntry { + dst := src[:0] + var pre sparseEntry + for _, cur := range src { + if cur.Length == 0 { + continue // Skip empty fragments + } + pre.Length = cur.Offset - pre.Offset + if pre.Length > 0 { + dst = append(dst, pre) // Only add non-empty fragments + } + pre.Offset = cur.endOffset() + } + pre.Length = size - pre.Offset // Possibly the only empty fragment + return append(dst, pre) +} + +// fileState tracks the number of logical (includes sparse holes) and physical +// (actual in tar archive) bytes remaining for the current file. +// +// Invariant: LogicalRemaining >= PhysicalRemaining +type fileState interface { + LogicalRemaining() int64 + PhysicalRemaining() int64 +} + +// allowedFormats determines which formats can be used. +// The value returned is the logical OR of multiple possible formats. +// If the value is FormatUnknown, then the input Header cannot be encoded +// and an error is returned explaining why. +// +// As a by-product of checking the fields, this function returns paxHdrs, which +// contain all fields that could not be directly encoded. +// A value receiver ensures that this method does not mutate the source Header. +func (h Header) allowedFormats() (format Format, paxHdrs map[string]string, err error) { + format = FormatUSTAR | FormatPAX | FormatGNU + paxHdrs = make(map[string]string) + + var whyNoUSTAR, whyNoPAX, whyNoGNU string + var preferPAX bool // Prefer PAX over USTAR + verifyString := func(s string, size int, name, paxKey string) { + // NUL-terminator is optional for path and linkpath. + // Technically, it is required for uname and gname, + // but neither GNU nor BSD tar checks for it. + tooLong := len(s) > size + allowLongGNU := paxKey == paxPath || paxKey == paxLinkpath + if hasNUL(s) || (tooLong && !allowLongGNU) { + whyNoGNU = fmt.Sprintf("GNU cannot encode %s=%q", name, s) + format.mustNotBe(FormatGNU) + } + if !isASCII(s) || tooLong { + canSplitUSTAR := paxKey == paxPath + if _, _, ok := splitUSTARPath(s); !canSplitUSTAR || !ok { + whyNoUSTAR = fmt.Sprintf("USTAR cannot encode %s=%q", name, s) + format.mustNotBe(FormatUSTAR) + } + if paxKey == paxNone { + whyNoPAX = fmt.Sprintf("PAX cannot encode %s=%q", name, s) + format.mustNotBe(FormatPAX) + } else { + paxHdrs[paxKey] = s + } + } + if v, ok := h.PAXRecords[paxKey]; ok && v == s { + paxHdrs[paxKey] = v + } + } + verifyNumeric := func(n int64, size int, name, paxKey string) { + if !fitsInBase256(size, n) { + whyNoGNU = fmt.Sprintf("GNU cannot encode %s=%d", name, n) + format.mustNotBe(FormatGNU) + } + if !fitsInOctal(size, n) { + whyNoUSTAR = fmt.Sprintf("USTAR cannot encode %s=%d", name, n) + format.mustNotBe(FormatUSTAR) + if paxKey == paxNone { + whyNoPAX = fmt.Sprintf("PAX cannot encode %s=%d", name, n) + format.mustNotBe(FormatPAX) + } else { + paxHdrs[paxKey] = strconv.FormatInt(n, 10) + } + } + if v, ok := h.PAXRecords[paxKey]; ok && v == strconv.FormatInt(n, 10) { + paxHdrs[paxKey] = v + } + } + verifyTime := func(ts time.Time, size int, name, paxKey string) { + if ts.IsZero() { + return // Always okay + } + if !fitsInBase256(size, ts.Unix()) { + whyNoGNU = fmt.Sprintf("GNU cannot encode %s=%v", name, ts) + format.mustNotBe(FormatGNU) + } + isMtime := paxKey == paxMtime + fitsOctal := fitsInOctal(size, ts.Unix()) + if (isMtime && !fitsOctal) || !isMtime { + whyNoUSTAR = fmt.Sprintf("USTAR cannot encode %s=%v", name, ts) + format.mustNotBe(FormatUSTAR) + } + needsNano := ts.Nanosecond() != 0 + if !isMtime || !fitsOctal || needsNano { + preferPAX = true // USTAR may truncate sub-second measurements + if paxKey == paxNone { + whyNoPAX = fmt.Sprintf("PAX cannot encode %s=%v", name, ts) + format.mustNotBe(FormatPAX) + } else { + paxHdrs[paxKey] = formatPAXTime(ts) + } + } + if v, ok := h.PAXRecords[paxKey]; ok && v == formatPAXTime(ts) { + paxHdrs[paxKey] = v + } + } + + // Check basic fields. + var blk block + v7 := blk.V7() + ustar := blk.USTAR() + gnu := blk.GNU() + verifyString(h.Name, len(v7.Name()), "Name", paxPath) + verifyString(h.Linkname, len(v7.LinkName()), "Linkname", paxLinkpath) + verifyString(h.Uname, len(ustar.UserName()), "Uname", paxUname) + verifyString(h.Gname, len(ustar.GroupName()), "Gname", paxGname) + verifyNumeric(h.Mode, len(v7.Mode()), "Mode", paxNone) + verifyNumeric(int64(h.Uid), len(v7.UID()), "Uid", paxUid) + verifyNumeric(int64(h.Gid), len(v7.GID()), "Gid", paxGid) + verifyNumeric(h.Size, len(v7.Size()), "Size", paxSize) + verifyNumeric(h.Devmajor, len(ustar.DevMajor()), "Devmajor", paxNone) + verifyNumeric(h.Devminor, len(ustar.DevMinor()), "Devminor", paxNone) + verifyTime(h.ModTime, len(v7.ModTime()), "ModTime", paxMtime) + verifyTime(h.AccessTime, len(gnu.AccessTime()), "AccessTime", paxAtime) + verifyTime(h.ChangeTime, len(gnu.ChangeTime()), "ChangeTime", paxCtime) + + // Check for header-only types. + var whyOnlyPAX, whyOnlyGNU string + switch h.Typeflag { + case TypeReg, TypeChar, TypeBlock, TypeFifo, TypeGNUSparse: + // Exclude TypeLink and TypeSymlink, since they may reference directories. + if strings.HasSuffix(h.Name, "/") { + return FormatUnknown, nil, headerError{"filename may not have trailing slash"} + } + case TypeXHeader, TypeGNULongName, TypeGNULongLink: + return FormatUnknown, nil, headerError{"cannot manually encode TypeXHeader, TypeGNULongName, or TypeGNULongLink headers"} + case TypeXGlobalHeader: + h2 := Header{Name: h.Name, Typeflag: h.Typeflag, Xattrs: h.Xattrs, PAXRecords: h.PAXRecords, Format: h.Format} + if !reflect.DeepEqual(h, h2) { + return FormatUnknown, nil, headerError{"only PAXRecords should be set for TypeXGlobalHeader"} + } + whyOnlyPAX = "only PAX supports TypeXGlobalHeader" + format.mayOnlyBe(FormatPAX) + } + if !isHeaderOnlyType(h.Typeflag) && h.Size < 0 { + return FormatUnknown, nil, headerError{"negative size on header-only type"} + } + + // Check PAX records. + if len(h.Xattrs) > 0 { + for k, v := range h.Xattrs { + paxHdrs[paxSchilyXattr+k] = v + } + whyOnlyPAX = "only PAX supports Xattrs" + format.mayOnlyBe(FormatPAX) + } + if len(h.PAXRecords) > 0 { + for k, v := range h.PAXRecords { + switch _, exists := paxHdrs[k]; { + case exists: + continue // Do not overwrite existing records + case h.Typeflag == TypeXGlobalHeader: + paxHdrs[k] = v // Copy all records + case !basicKeys[k] && !strings.HasPrefix(k, paxGNUSparse): + paxHdrs[k] = v // Ignore local records that may conflict + } + } + whyOnlyPAX = "only PAX supports PAXRecords" + format.mayOnlyBe(FormatPAX) + } + for k, v := range paxHdrs { + if !validPAXRecord(k, v) { + return FormatUnknown, nil, headerError{fmt.Sprintf("invalid PAX record: %q", k+" = "+v)} + } + } + + // TODO(dsnet): Re-enable this when adding sparse support. + // See https://golang.org/issue/22735 + /* + // Check sparse files. + if len(h.SparseHoles) > 0 || h.Typeflag == TypeGNUSparse { + if isHeaderOnlyType(h.Typeflag) { + return FormatUnknown, nil, headerError{"header-only type cannot be sparse"} + } + if !validateSparseEntries(h.SparseHoles, h.Size) { + return FormatUnknown, nil, headerError{"invalid sparse holes"} + } + if h.Typeflag == TypeGNUSparse { + whyOnlyGNU = "only GNU supports TypeGNUSparse" + format.mayOnlyBe(FormatGNU) + } else { + whyNoGNU = "GNU supports sparse files only with TypeGNUSparse" + format.mustNotBe(FormatGNU) + } + whyNoUSTAR = "USTAR does not support sparse files" + format.mustNotBe(FormatUSTAR) + } + */ + + // Check desired format. + if wantFormat := h.Format; wantFormat != FormatUnknown { + if wantFormat.has(FormatPAX) && !preferPAX { + wantFormat.mayBe(FormatUSTAR) // PAX implies USTAR allowed too + } + format.mayOnlyBe(wantFormat) // Set union of formats allowed and format wanted + } + if format == FormatUnknown { + switch h.Format { + case FormatUSTAR: + err = headerError{"Format specifies USTAR", whyNoUSTAR, whyOnlyPAX, whyOnlyGNU} + case FormatPAX: + err = headerError{"Format specifies PAX", whyNoPAX, whyOnlyGNU} + case FormatGNU: + err = headerError{"Format specifies GNU", whyNoGNU, whyOnlyPAX} + default: + err = headerError{whyNoUSTAR, whyNoPAX, whyNoGNU, whyOnlyPAX, whyOnlyGNU} + } + } + return format, paxHdrs, err +} + // FileInfo returns an os.FileInfo for the Header. func (h *Header) FileInfo() os.FileInfo { return headerFileInfo{h} @@ -97,63 +555,43 @@ func (fi headerFileInfo) Mode() (mode os.FileMode) { // Set setuid, setgid and sticky bits. if fi.h.Mode&c_ISUID != 0 { - // setuid mode |= os.ModeSetuid } if fi.h.Mode&c_ISGID != 0 { - // setgid mode |= os.ModeSetgid } if fi.h.Mode&c_ISVTX != 0 { - // sticky mode |= os.ModeSticky } - // Set file mode bits. - // clear perm, setuid, setgid and sticky bits. - m := os.FileMode(fi.h.Mode) &^ 07777 - if m == c_ISDIR { - // directory + // Set file mode bits; clear perm, setuid, setgid, and sticky bits. + switch m := os.FileMode(fi.h.Mode) &^ 07777; m { + case c_ISDIR: mode |= os.ModeDir - } - if m == c_ISFIFO { - // named pipe (FIFO) + case c_ISFIFO: mode |= os.ModeNamedPipe - } - if m == c_ISLNK { - // symbolic link + case c_ISLNK: mode |= os.ModeSymlink - } - if m == c_ISBLK { - // device file + case c_ISBLK: mode |= os.ModeDevice - } - if m == c_ISCHR { - // Unix character device + case c_ISCHR: mode |= os.ModeDevice mode |= os.ModeCharDevice - } - if m == c_ISSOCK { - // Unix domain socket + case c_ISSOCK: mode |= os.ModeSocket } switch fi.h.Typeflag { case TypeSymlink: - // symbolic link mode |= os.ModeSymlink case TypeChar: - // character device node mode |= os.ModeDevice mode |= os.ModeCharDevice case TypeBlock: - // block device node mode |= os.ModeDevice case TypeDir: - // directory mode |= os.ModeDir case TypeFifo: - // fifo node mode |= os.ModeNamedPipe } @@ -163,11 +601,15 @@ func (fi headerFileInfo) Mode() (mode os.FileMode) { // sysStat, if non-nil, populates h from system-dependent fields of fi. var sysStat func(fi os.FileInfo, h *Header) error -// Mode constants from the tar spec. const ( - c_ISUID = 04000 // Set uid - c_ISGID = 02000 // Set gid - c_ISVTX = 01000 // Save text (sticky bit) + // Mode constants from the USTAR spec: + // See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/pax.html#tag_20_92_13_06 + c_ISUID = 04000 // Set uid + c_ISGID = 02000 // Set gid + c_ISVTX = 01000 // Save text (sticky bit) + + // Common Unix mode constants; these are not defined in any common tar standard. + // Header.FileInfo understands these, but FileInfoHeader will never produce these. c_ISDIR = 040000 // Directory c_ISFIFO = 010000 // FIFO c_ISREG = 0100000 // Regular file @@ -177,33 +619,16 @@ const ( c_ISSOCK = 0140000 // Socket ) -// Keywords for the PAX Extended Header -const ( - paxAtime = "atime" - paxCharset = "charset" - paxComment = "comment" - paxCtime = "ctime" // please note that ctime is not a valid pax header. - paxGid = "gid" - paxGname = "gname" - paxLinkpath = "linkpath" - paxMtime = "mtime" - paxPath = "path" - paxSize = "size" - paxUid = "uid" - paxUname = "uname" - paxXattr = "SCHILY.xattr." - paxNone = "" -) - // FileInfoHeader creates a partially-populated Header from fi. // If fi describes a symlink, FileInfoHeader records link as the link target. // If fi describes a directory, a slash is appended to the name. -// Because os.FileInfo's Name method returns only the base name of -// the file it describes, it may be necessary to modify the Name field -// of the returned header to provide the full path name of the file. +// +// Since os.FileInfo's Name method only returns the base name of +// the file it describes, it may be necessary to modify Header.Name +// to provide the full path name of the file. func FileInfoHeader(fi os.FileInfo, link string) (*Header, error) { if fi == nil { - return nil, errors.New("tar: FileInfo is nil") + return nil, errors.New("archive/tar: FileInfo is nil") } fm := fi.Mode() h := &Header{ @@ -213,30 +638,24 @@ func FileInfoHeader(fi os.FileInfo, link string) (*Header, error) { } switch { case fm.IsRegular(): - h.Mode |= c_ISREG h.Typeflag = TypeReg h.Size = fi.Size() case fi.IsDir(): h.Typeflag = TypeDir - h.Mode |= c_ISDIR h.Name += "/" case fm&os.ModeSymlink != 0: h.Typeflag = TypeSymlink - h.Mode |= c_ISLNK h.Linkname = link case fm&os.ModeDevice != 0: if fm&os.ModeCharDevice != 0 { - h.Mode |= c_ISCHR h.Typeflag = TypeChar } else { - h.Mode |= c_ISBLK h.Typeflag = TypeBlock } case fm&os.ModeNamedPipe != 0: h.Typeflag = TypeFifo - h.Mode |= c_ISFIFO case fm&os.ModeSocket != 0: - h.Mode |= c_ISSOCK + return nil, fmt.Errorf("archive/tar: sockets not supported") default: return nil, fmt.Errorf("archive/tar: unknown file mode %v", fm) } @@ -272,6 +691,12 @@ func FileInfoHeader(fi os.FileInfo, link string) (*Header, error) { h.Size = 0 h.Linkname = sys.Linkname } + if sys.PAXRecords != nil { + h.PAXRecords = make(map[string]string) + for k, v := range sys.PAXRecords { + h.PAXRecords[k] = v + } + } } if sysStat != nil { return h, sysStat(fi, h) @@ -279,55 +704,6 @@ func FileInfoHeader(fi os.FileInfo, link string) (*Header, error) { return h, nil } -var zeroBlock = make([]byte, blockSize) - -// POSIX specifies a sum of the unsigned byte values, but the Sun tar uses signed byte values. -// We compute and return both. -func checksum(header []byte) (unsigned int64, signed int64) { - for i := 0; i < len(header); i++ { - if i == 148 { - // The chksum field (header[148:156]) is special: it should be treated as space bytes. - unsigned += ' ' * 8 - signed += ' ' * 8 - i += 7 - continue - } - unsigned += int64(header[i]) - signed += int64(int8(header[i])) - } - return -} - -type slicer []byte - -func (sp *slicer) next(n int) (b []byte) { - s := *sp - b, *sp = s[0:n], s[n:] - return -} - -func isASCII(s string) bool { - for _, c := range s { - if c >= 0x80 { - return false - } - } - return true -} - -func toASCII(s string) string { - if isASCII(s) { - return s - } - var buf bytes.Buffer - for _, c := range s { - if c < 0x80 { - buf.WriteByte(byte(c)) - } - } - return buf.String() -} - // isHeaderOnlyType checks if the given type flag is of the type that has no // data section even if a size is specified. func isHeaderOnlyType(flag byte) bool { @@ -338,3 +714,10 @@ func isHeaderOnlyType(flag byte) bool { return false } } + +func min(a, b int64) int64 { + if a < b { + return a + } + return b +} |