mirror of https://github.com/vbatts/go-mtree.git
175 lines
7.7 KiB
Go
175 lines
7.7 KiB
Go
package mtree
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import (
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"archive/tar"
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"crypto/md5"
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"crypto/sha1"
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"crypto/sha256"
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"crypto/sha512"
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"fmt"
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"hash"
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"io"
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"os"
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"github.com/vbatts/go-mtree/pkg/govis"
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//nolint:staticcheck // SA1019 yes ripemd160 is deprecated, but this is for mtree compatibility
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"golang.org/x/crypto/ripemd160"
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)
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// KeywordFunc is the type of a function called on each file to be included in
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// a DirectoryHierarchy, that will produce the string output of the keyword to
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// be included for the file entry. Otherwise, empty string.
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// io.Reader `r` is to the file stream for the file payload. While this
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// function takes an io.Reader, the caller needs to reset it to the beginning
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// for each new KeywordFunc
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type KeywordFunc func(path string, info os.FileInfo, r io.Reader) ([]KeyVal, error)
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var (
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// KeywordFuncs is the map of all keywords (and the functions to produce them)
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KeywordFuncs = map[Keyword]KeywordFunc{
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"size": sizeKeywordFunc, // The size, in bytes, of the file
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"type": typeKeywordFunc, // The type of the file
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"time": timeKeywordFunc, // The last modification time of the file
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"link": linkKeywordFunc, // The target of the symbolic link when type=link
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"uid": uidKeywordFunc, // The file owner as a numeric value
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"gid": gidKeywordFunc, // The file group as a numeric value
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"nlink": nlinkKeywordFunc, // The number of hard links the file is expected to have
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"uname": unameKeywordFunc, // The file owner as a symbolic name
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"gname": gnameKeywordFunc, // The file group as a symbolic name
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"mode": modeKeywordFunc, // The current file's permissions as a numeric (octal) or symbolic value
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"cksum": cksumKeywordFunc, // The checksum of the file using the default algorithm specified by the cksum(1) utility
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"md5": hasherKeywordFunc("md5digest", md5.New), // The MD5 message digest of the file
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"md5digest": hasherKeywordFunc("md5digest", md5.New), // A synonym for `md5`
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"rmd160": hasherKeywordFunc("ripemd160digest", ripemd160.New), // The RIPEMD160 message digest of the file
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"rmd160digest": hasherKeywordFunc("ripemd160digest", ripemd160.New), // A synonym for `rmd160`
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"ripemd160digest": hasherKeywordFunc("ripemd160digest", ripemd160.New), // A synonym for `rmd160`
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"sha1": hasherKeywordFunc("sha1digest", sha1.New), // The SHA1 message digest of the file
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"sha1digest": hasherKeywordFunc("sha1digest", sha1.New), // A synonym for `sha1`
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"sha256": hasherKeywordFunc("sha256digest", sha256.New), // The SHA256 message digest of the file
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"sha256digest": hasherKeywordFunc("sha256digest", sha256.New), // A synonym for `sha256`
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"sha384": hasherKeywordFunc("sha384digest", sha512.New384), // The SHA384 message digest of the file
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"sha384digest": hasherKeywordFunc("sha384digest", sha512.New384), // A synonym for `sha384`
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"sha512": hasherKeywordFunc("sha512digest", sha512.New), // The SHA512 message digest of the file
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"sha512digest": hasherKeywordFunc("sha512digest", sha512.New), // A synonym for `sha512`
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"sha512256": hasherKeywordFunc("sha512digest", sha512.New512_256), // The SHA512/256 message digest of the file
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"sha512256digest": hasherKeywordFunc("sha512digest", sha512.New512_256), // A synonym for `sha512256`
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"flags": flagsKeywordFunc, // NOTE: this is a noop, but here to support the presence of the "flags" keyword.
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// This is not an upstreamed keyword, but used to vary from "time", as tar
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// archives do not store nanosecond precision. So comparing on "time" will
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// be only seconds level accurate.
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"tar_time": tartimeKeywordFunc, // The last modification time of the file, from a tar archive mtime
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// This is not an upstreamed keyword, but a needed attribute for file validation.
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// The pattern for this keyword key is prefixed by "xattr." followed by the extended attribute "namespace.key".
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// The keyword value is the SHA1 digest of the extended attribute's value.
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// In this way, the order of the keys does not matter, and the contents of the value is not revealed.
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"xattr": xattrKeywordFunc,
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"xattrs": xattrKeywordFunc,
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}
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)
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var (
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modeKeywordFunc = func(path string, info os.FileInfo, r io.Reader) ([]KeyVal, error) {
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permissions := info.Mode().Perm()
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if os.ModeSetuid&info.Mode() > 0 {
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permissions |= (1 << 11)
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}
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if os.ModeSetgid&info.Mode() > 0 {
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permissions |= (1 << 10)
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}
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if os.ModeSticky&info.Mode() > 0 {
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permissions |= (1 << 9)
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}
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return []KeyVal{KeyVal(fmt.Sprintf("mode=%#o", permissions))}, nil
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}
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sizeKeywordFunc = func(path string, info os.FileInfo, r io.Reader) ([]KeyVal, error) {
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if sys, ok := info.Sys().(*tar.Header); ok {
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if sys.Typeflag == tar.TypeSymlink {
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return []KeyVal{KeyVal(fmt.Sprintf("size=%d", len(sys.Linkname)))}, nil
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}
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}
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return []KeyVal{KeyVal(fmt.Sprintf("size=%d", info.Size()))}, nil
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}
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cksumKeywordFunc = func(path string, info os.FileInfo, r io.Reader) ([]KeyVal, error) {
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if !info.Mode().IsRegular() {
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return nil, nil
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}
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sum, _, err := cksum(r)
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if err != nil {
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return nil, err
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}
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return []KeyVal{KeyVal(fmt.Sprintf("cksum=%d", sum))}, nil
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}
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hasherKeywordFunc = func(name string, newHash func() hash.Hash) KeywordFunc {
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return func(path string, info os.FileInfo, r io.Reader) ([]KeyVal, error) {
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if !info.Mode().IsRegular() {
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return nil, nil
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}
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h := newHash()
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if _, err := io.Copy(h, r); err != nil {
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return nil, err
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}
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return []KeyVal{KeyVal(fmt.Sprintf("%s=%x", KeywordSynonym(name), h.Sum(nil)))}, nil
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}
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}
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tartimeKeywordFunc = func(path string, info os.FileInfo, r io.Reader) ([]KeyVal, error) {
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return []KeyVal{KeyVal(fmt.Sprintf("tar_time=%d.%9.9d", info.ModTime().Unix(), 0))}, nil
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}
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timeKeywordFunc = func(path string, info os.FileInfo, r io.Reader) ([]KeyVal, error) {
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tSec := info.ModTime().Unix()
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tNano := info.ModTime().Nanosecond()
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return []KeyVal{KeyVal(fmt.Sprintf("time=%d.%9.9d", tSec, tNano))}, nil
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}
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linkKeywordFunc = func(path string, info os.FileInfo, r io.Reader) ([]KeyVal, error) {
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if sys, ok := info.Sys().(*tar.Header); ok {
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if sys.Linkname != "" {
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linkname, err := govis.Vis(sys.Linkname, DefaultVisFlags)
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if err != nil {
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return nil, nil
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}
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return []KeyVal{KeyVal(fmt.Sprintf("link=%s", linkname))}, nil
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}
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return nil, nil
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}
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if info.Mode()&os.ModeSymlink != 0 {
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str, err := os.Readlink(path)
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if err != nil {
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return nil, nil
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}
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linkname, err := govis.Vis(str, DefaultVisFlags)
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if err != nil {
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return nil, nil
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}
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return []KeyVal{KeyVal(fmt.Sprintf("link=%s", linkname))}, nil
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}
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return nil, nil
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}
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typeKeywordFunc = func(path string, info os.FileInfo, r io.Reader) ([]KeyVal, error) {
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if info.Mode().IsDir() {
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return []KeyVal{"type=dir"}, nil
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}
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if info.Mode().IsRegular() {
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return []KeyVal{"type=file"}, nil
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}
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if info.Mode()&os.ModeSocket != 0 {
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return []KeyVal{"type=socket"}, nil
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}
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if info.Mode()&os.ModeSymlink != 0 {
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return []KeyVal{"type=link"}, nil
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}
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if info.Mode()&os.ModeNamedPipe != 0 {
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return []KeyVal{"type=fifo"}, nil
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}
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if info.Mode()&os.ModeDevice != 0 {
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if info.Mode()&os.ModeCharDevice != 0 {
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return []KeyVal{"type=char"}, nil
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}
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return []KeyVal{"type=block"}, nil
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}
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return nil, nil
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}
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)
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