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tar-split/tar/verify/headers.go

100 lines
2.4 KiB
Go

package verify
import (
"os"
"path/filepath"
"strings"
"time"
)
// PosixHeader is the structure from a POSIX tar header, to be marshalled from
// the tar stream, and available for on-disk comparison and verification
type PosixHeader struct {
Name string `json:"name,omitempty"`
Mode os.FileMode `json:"mode,omitempty"`
UID uint32 `json:"uid,omitempty"`
GID uint32 `json:"gid,omitempty"`
Size int64 `json:"size,omitempty"`
Mtime time.Time `json:"mtime,omitempty"`
Checksum []byte `json:"chksum,omitempty"`
LinkName string `json:"linkname,omitempty"`
Magic []byte `json:"magic,omitempty"`
Version string `json:"version,omitempty"`
Uname string `json:"uname,omitempty"`
Gname string `json:"gname,omitempty"`
DevMajor int `json:"devmajor,omitempty"`
DevMinor int `json:"devminor,omitempty"`
Prefix string `json:"prefix,omitempty"`
}
type PaxHeader struct {
Atime time.Time
Ctime time.Time
Xattrs map[string]string
}
type Header struct {
// maybe I do not want these grouped like this. Maybe this should be an interface instead.
Posix PosixHeader
Pax PaxHeader
}
// Size returns file size (implements Sizer)
func (hdr Header) Size() int64 {
return int64(hdr.Posix.Size)
}
// ModTime returns file mtime (implements ModTimer)
func (hdr Header) ModTime() time.Time {
return hdr.Posix.Mtime
}
// Mode returns file mode (implements Moder)
func (hdr Header) Mode() os.FileMode {
return hdr.Posix.Mode
}
func (hdr Header) LinkName() string {
return hdr.Posix.LinkName
}
// HeaderFromFile takes a relative root and the filename of the file to collect
// information on.
func HeaderFromFile(rel, filename string) (*Header, error) {
absRel, err := filepath.Abs(rel)
if err != nil {
return nil, err
}
if strings.HasPrefix(filename, "/") {
var err error
filename, err = filepath.Abs(filename)
if err != nil {
return nil, err
}
}
stat, err := os.Lstat(filename)
if err != nil {
return nil, err
}
name := filename
if strings.HasPrefix(filename, absRel) {
name = strings.TrimPrefix(filename, absRel)
}
hdr := Header{
Posix: PosixHeader{
Name: name,
Size: stat.Size(),
Mode: stat.Mode(),
Mtime: stat.ModTime(),
},
}
if stat.Mode()&os.ModeSymlink != 0 {
l, _ := os.Readlink(filename) // if this errors, the empty string is OK
hdr.Posix.LinkName = l
}
return &hdr, nil
}