mirror of
https://github.com/vbatts/go-mtree.git
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Vincent Batts
fc5450ed71
This allows for restoring some attributes of files from the state in an mtree Manifest Reported-by: Matthew Garrett <Matthewgarrett@google.com> Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>
108 lines
2.9 KiB
Go
108 lines
2.9 KiB
Go
package mtree
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import (
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"fmt"
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"os"
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"strconv"
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"strings"
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"time"
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)
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// UpdateKeywordFunc is the signature for a function that will restore a file's
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// attributes. Where path is relative path to the file, and value to be
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// restored to.
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type UpdateKeywordFunc func(path string, value string) (os.FileInfo, error)
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// UpdateKeywordFuncs is the registered list of functions to update file attributes.
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// Keyed by the keyword as it would show up in the manifest
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var UpdateKeywordFuncs = map[Keyword]UpdateKeywordFunc{
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"mode": modeUpdateKeywordFunc,
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"time": timeUpdateKeywordFunc,
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"tar_time": tartimeUpdateKeywordFunc,
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"uid": uidUpdateKeywordFunc,
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"gid": gidUpdateKeywordFunc,
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}
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func uidUpdateKeywordFunc(path, value string) (os.FileInfo, error) {
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uid, err := strconv.Atoi(value)
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if err != nil {
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return nil, err
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}
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if err := os.Lchown(path, uid, -1); err != nil {
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return nil, err
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}
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return os.Lstat(path)
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}
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func gidUpdateKeywordFunc(path, value string) (os.FileInfo, error) {
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gid, err := strconv.Atoi(value)
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if err != nil {
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return nil, err
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}
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if err := os.Lchown(path, -1, gid); err != nil {
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return nil, err
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}
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return os.Lstat(path)
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}
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func modeUpdateKeywordFunc(path, value string) (os.FileInfo, error) {
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vmode, err := strconv.ParseInt(value, 8, 32)
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if err != nil {
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return nil, err
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}
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Debugf("path: %q, value: %q, vmode: %o", path, value, vmode)
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if err := os.Chmod(path, os.FileMode(vmode)); err != nil {
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return nil, err
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}
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return os.Lstat(path)
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}
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// since tar_time will only be second level precision, then when restoring the
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// filepath from a tar_time, then compare the seconds first and only Chtimes if
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// the seconds value is different.
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func tartimeUpdateKeywordFunc(path, value string) (os.FileInfo, error) {
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info, err := os.Lstat(path)
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if err != nil {
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return nil, err
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}
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v := strings.SplitN(value, ".", 2)
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if len(v) != 2 {
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return nil, fmt.Errorf("expected a number like 1469104727.000000000")
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}
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sec, err := strconv.ParseInt(v[0], 10, 64)
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if err != nil {
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return nil, fmt.Errorf("expected seconds, but got %q", v[0])
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}
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// if the seconds are the same, don't do anything, because the file might
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// have nanosecond value, and if using tar_time it would zero it out.
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if info.ModTime().Unix() == sec {
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return info, nil
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}
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vtime := time.Unix(sec, 0)
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if err := os.Chtimes(path, vtime, vtime); err != nil {
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return nil, err
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}
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return os.Lstat(path)
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}
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// this is nano second precision
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func timeUpdateKeywordFunc(path, value string) (os.FileInfo, error) {
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v := strings.SplitN(value, ".", 2)
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if len(v) != 2 {
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return nil, fmt.Errorf("expected a number like 1469104727.871937272")
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}
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nsec, err := strconv.ParseInt(v[0]+v[1], 10, 64)
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if err != nil {
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return nil, fmt.Errorf("expected nano seconds, but got %q", v[0]+v[1])
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}
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Debugf("arg: %q; nsec: %q", v[0]+v[1], nsec)
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vtime := time.Unix(0, nsec)
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if err := os.Chtimes(path, vtime, vtime); err != nil {
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return nil, err
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}
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return os.Lstat(path)
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}
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