| // Copyright 2009 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // Package tar implements access to tar archives. |
| // |
| // 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 ( |
| "errors" |
| "fmt" |
| "io/fs" |
| "math" |
| "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 ( |
| // 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 { |
| // 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 |
| } |
| |
| // 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 fs.FileInfo for the Header. |
| func (h *Header) FileInfo() fs.FileInfo { |
| return headerFileInfo{h} |
| } |
| |
| // headerFileInfo implements fs.FileInfo. |
| type headerFileInfo struct { |
| h *Header |
| } |
| |
| func (fi headerFileInfo) Size() int64 { return fi.h.Size } |
| func (fi headerFileInfo) IsDir() bool { return fi.Mode().IsDir() } |
| func (fi headerFileInfo) ModTime() time.Time { return fi.h.ModTime } |
| func (fi headerFileInfo) Sys() interface{} { return fi.h } |
| |
| // Name returns the base name of the file. |
| func (fi headerFileInfo) Name() string { |
| if fi.IsDir() { |
| return path.Base(path.Clean(fi.h.Name)) |
| } |
| return path.Base(fi.h.Name) |
| } |
| |
| // Mode returns the permission and mode bits for the headerFileInfo. |
| func (fi headerFileInfo) Mode() (mode fs.FileMode) { |
| // Set file permission bits. |
| mode = fs.FileMode(fi.h.Mode).Perm() |
| |
| // Set setuid, setgid and sticky bits. |
| if fi.h.Mode&c_ISUID != 0 { |
| mode |= fs.ModeSetuid |
| } |
| if fi.h.Mode&c_ISGID != 0 { |
| mode |= fs.ModeSetgid |
| } |
| if fi.h.Mode&c_ISVTX != 0 { |
| mode |= fs.ModeSticky |
| } |
| |
| // Set file mode bits; clear perm, setuid, setgid, and sticky bits. |
| switch m := fs.FileMode(fi.h.Mode) &^ 07777; m { |
| case c_ISDIR: |
| mode |= fs.ModeDir |
| case c_ISFIFO: |
| mode |= fs.ModeNamedPipe |
| case c_ISLNK: |
| mode |= fs.ModeSymlink |
| case c_ISBLK: |
| mode |= fs.ModeDevice |
| case c_ISCHR: |
| mode |= fs.ModeDevice |
| mode |= fs.ModeCharDevice |
| case c_ISSOCK: |
| mode |= fs.ModeSocket |
| } |
| |
| switch fi.h.Typeflag { |
| case TypeSymlink: |
| mode |= fs.ModeSymlink |
| case TypeChar: |
| mode |= fs.ModeDevice |
| mode |= fs.ModeCharDevice |
| case TypeBlock: |
| mode |= fs.ModeDevice |
| case TypeDir: |
| mode |= fs.ModeDir |
| case TypeFifo: |
| mode |= fs.ModeNamedPipe |
| } |
| |
| return mode |
| } |
| |
| // sysStat, if non-nil, populates h from system-dependent fields of fi. |
| var sysStat func(fi fs.FileInfo, h *Header) error |
| |
| const ( |
| // 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 |
| c_ISLNK = 0120000 // Symbolic link |
| c_ISBLK = 060000 // Block special file |
| c_ISCHR = 020000 // Character special file |
| c_ISSOCK = 0140000 // Socket |
| ) |
| |
| // 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. |
| // |
| // Since fs.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 fs.FileInfo, link string) (*Header, error) { |
| if fi == nil { |
| return nil, errors.New("archive/tar: FileInfo is nil") |
| } |
| fm := fi.Mode() |
| h := &Header{ |
| Name: fi.Name(), |
| ModTime: fi.ModTime(), |
| Mode: int64(fm.Perm()), // or'd with c_IS* constants later |
| } |
| switch { |
| case fm.IsRegular(): |
| h.Typeflag = TypeReg |
| h.Size = fi.Size() |
| case fi.IsDir(): |
| h.Typeflag = TypeDir |
| h.Name += "/" |
| case fm&fs.ModeSymlink != 0: |
| h.Typeflag = TypeSymlink |
| h.Linkname = link |
| case fm&fs.ModeDevice != 0: |
| if fm&fs.ModeCharDevice != 0 { |
| h.Typeflag = TypeChar |
| } else { |
| h.Typeflag = TypeBlock |
| } |
| case fm&fs.ModeNamedPipe != 0: |
| h.Typeflag = TypeFifo |
| case fm&fs.ModeSocket != 0: |
| return nil, fmt.Errorf("archive/tar: sockets not supported") |
| default: |
| return nil, fmt.Errorf("archive/tar: unknown file mode %v", fm) |
| } |
| if fm&fs.ModeSetuid != 0 { |
| h.Mode |= c_ISUID |
| } |
| if fm&fs.ModeSetgid != 0 { |
| h.Mode |= c_ISGID |
| } |
| if fm&fs.ModeSticky != 0 { |
| h.Mode |= c_ISVTX |
| } |
| // If possible, populate additional fields from OS-specific |
| // FileInfo fields. |
| if sys, ok := fi.Sys().(*Header); ok { |
| // This FileInfo came from a Header (not the OS). Use the |
| // original Header to populate all remaining fields. |
| h.Uid = sys.Uid |
| h.Gid = sys.Gid |
| h.Uname = sys.Uname |
| h.Gname = sys.Gname |
| h.AccessTime = sys.AccessTime |
| h.ChangeTime = sys.ChangeTime |
| if sys.Xattrs != nil { |
| h.Xattrs = make(map[string]string) |
| for k, v := range sys.Xattrs { |
| h.Xattrs[k] = v |
| } |
| } |
| if sys.Typeflag == TypeLink { |
| // hard link |
| h.Typeflag = TypeLink |
| 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) |
| } |
| return h, nil |
| } |
| |
| // 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 { |
| switch flag { |
| case TypeLink, TypeSymlink, TypeChar, TypeBlock, TypeDir, TypeFifo: |
| return true |
| default: |
| return false |
| } |
| } |
| |
| func min(a, b int64) int64 { |
| if a < b { |
| return a |
| } |
| return b |
| } |
