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