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tar-split/keywords.go
Stephen Chung e29b993aa2 keywords: obtain all permission bits
Fixes #7. Upper 3 bits are 'special' mode bits, and are not
included when calling info.Mode().Perm(). Need to mask
the info.Mode() with the corresponding mode bit defined
by the go library to see if these bits are set or not.

Signed-off-by: Stephen Chung <schung@redhat.com>
2016-07-15 15:37:52 -04:00

260 lines
8.5 KiB
Go

package mtree
import (
"crypto/md5"
"crypto/sha1"
"crypto/sha256"
"crypto/sha512"
"fmt"
"hash"
"io"
"os"
"strings"
"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.
type KeywordFunc func(path string, info os.FileInfo) (string, error)
// KeyVal is a "keyword=value"
type KeyVal string
// Keyword is the mapping to the available keywords
func (kv KeyVal) Keyword() string {
if !strings.Contains(string(kv), "=") {
return ""
}
chunks := strings.SplitN(strings.TrimSpace(string(kv)), "=", 2)[0]
if !strings.Contains(chunks, ".") {
return chunks
}
return strings.SplitN(chunks, ".", 2)[0]
}
// KeywordSuffix is really only used for xattr, as the keyword is a prefix to
// the xattr "namespace.key"
func (kv KeyVal) KeywordSuffix() string {
if !strings.Contains(string(kv), "=") {
return ""
}
chunks := strings.SplitN(strings.TrimSpace(string(kv)), "=", 2)[0]
if !strings.Contains(chunks, ".") {
return ""
}
return strings.SplitN(chunks, ".", 2)[1]
}
// Value is the data/value portion of "keyword=value"
func (kv KeyVal) Value() string {
if !strings.Contains(string(kv), "=") {
return ""
}
return strings.SplitN(strings.TrimSpace(string(kv)), "=", 2)[1]
}
// keywordSelector takes an array of "keyword=value" and filters out that only the set of words
func keywordSelector(keyval, words []string) []string {
retList := []string{}
for _, kv := range keyval {
if inSlice(KeyVal(kv).Keyword(), words) {
retList = append(retList, kv)
}
}
return retList
}
// NewKeyVals constructs a list of KeyVal from the list of strings, like "keyword=value"
func NewKeyVals(keyvals []string) KeyVals {
kvs := make(KeyVals, len(keyvals))
for i := range keyvals {
kvs[i] = KeyVal(keyvals[i])
}
return kvs
}
// KeyVals is a list of KeyVal
type KeyVals []KeyVal
// Has the "keyword" present in the list of KeyVal, and returns the
// corresponding KeyVal, else an empty string.
func (kvs KeyVals) Has(keyword string) KeyVal {
for i := range kvs {
if kvs[i].Keyword() == keyword {
return kvs[i]
}
}
return emptyKV
}
var emptyKV = KeyVal("")
// MergeSet takes the current setKeyVals, and then applies the entryKeyVals
// such that the entry's values win. The union is returned.
func MergeSet(setKeyVals, entryKeyVals []string) KeyVals {
retList := NewKeyVals(append([]string{}, setKeyVals...))
eKVs := NewKeyVals(entryKeyVals)
seenKeywords := []string{}
for i := range retList {
word := retList[i].Keyword()
if ekv := eKVs.Has(word); ekv != emptyKV {
retList[i] = ekv
}
seenKeywords = append(seenKeywords, word)
}
for i := range eKVs {
if !inSlice(eKVs[i].Keyword(), seenKeywords) {
retList = append(retList, eKVs[i])
}
}
return retList
}
var (
// DefaultKeywords has the several default keyword producers (uid, gid,
// mode, nlink, type, size, mtime)
DefaultKeywords = []string{
"size",
"type",
"uid",
"gid",
"mode",
"link",
"nlink",
"time",
}
// SetKeywords is the default set of keywords calculated for a `/set` SpecialType
SetKeywords = []string{
"uid",
"gid",
}
// KeywordFuncs is the map of all keywords (and the functions to produce them)
KeywordFuncs = map[string]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
"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("md5", md5.New), // The MD5 message digest of the file
"md5digest": hasherKeywordFunc("md5digest", md5.New), // A synonym for `md5`
"rmd160": hasherKeywordFunc("rmd160", ripemd160.New), // The RIPEMD160 message digest of the file
"rmd160digest": hasherKeywordFunc("rmd160digest", ripemd160.New), // A synonym for `rmd160`
"ripemd160digest": hasherKeywordFunc("ripemd160digest", ripemd160.New), // A synonym for `rmd160`
"sha1": hasherKeywordFunc("sha1", sha1.New), // The SHA1 message digest of the file
"sha1digest": hasherKeywordFunc("sha1digest", sha1.New), // A synonym for `sha1`
"sha256": hasherKeywordFunc("sha256", sha256.New), // The SHA256 message digest of the file
"sha256digest": hasherKeywordFunc("sha256digest", sha256.New), // A synonym for `sha256`
"sha384": hasherKeywordFunc("sha384", sha512.New384), // The SHA384 message digest of the file
"sha384digest": hasherKeywordFunc("sha384digest", sha512.New384), // A synonym for `sha384`
"sha512": hasherKeywordFunc("sha512", sha512.New), // The SHA512 message digest of the file
"sha512digest": hasherKeywordFunc("sha512digest", sha512.New), // A synonym for `sha512`
// 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,
}
)
var (
modeKeywordFunc = func(path string, info os.FileInfo) (string, 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 fmt.Sprintf("mode=%#o", permissions), nil
}
sizeKeywordFunc = func(path string, info os.FileInfo) (string, error) {
return fmt.Sprintf("size=%d", info.Size()), nil
}
cksumKeywordFunc = func(path string, info os.FileInfo) (string, error) {
if !info.Mode().IsRegular() {
return "", nil
}
fh, err := os.Open(path)
if err != nil {
return "", err
}
defer fh.Close()
sum, _, err := cksum(fh)
if err != nil {
return "", err
}
return fmt.Sprintf("cksum=%d", sum), nil
}
hasherKeywordFunc = func(name string, newHash func() hash.Hash) KeywordFunc {
return func(path string, info os.FileInfo) (string, error) {
if !info.Mode().IsRegular() {
return "", nil
}
fh, err := os.Open(path)
if err != nil {
return "", err
}
defer fh.Close()
h := newHash()
if _, err := io.Copy(h, fh); err != nil {
return "", err
}
return fmt.Sprintf("%s=%x", name, h.Sum(nil)), nil
}
}
timeKeywordFunc = func(path string, info os.FileInfo) (string, error) {
t := info.ModTime().UnixNano()
if t == 0 {
return "time=0.000000000", nil
}
return fmt.Sprintf("time=%d.%9.9d", (t / 1e9), (t % (t / 1e9))), nil
}
linkKeywordFunc = func(path string, info os.FileInfo) (string, error) {
if info.Mode()&os.ModeSymlink != 0 {
str, err := os.Readlink(path)
if err != nil {
return "", err
}
return fmt.Sprintf("link=%s", str), nil
}
return "", nil
}
typeKeywordFunc = func(path string, info os.FileInfo) (string, error) {
if info.Mode().IsDir() {
return "type=dir", nil
}
if info.Mode().IsRegular() {
return "type=file", nil
}
if info.Mode()&os.ModeSocket != 0 {
return "type=socket", nil
}
if info.Mode()&os.ModeSymlink != 0 {
return "type=link", nil
}
if info.Mode()&os.ModeNamedPipe != 0 {
return "type=fifo", nil
}
if info.Mode()&os.ModeDevice != 0 {
if info.Mode()&os.ModeCharDevice != 0 {
return "type=char", nil
}
return "type=device", nil
}
return "", nil
}
)