Update tar to use PAXRecords instead of Xattrs

dmcgowan · dmcgowan · commit bc9cb25012ce · 2017-11-28T17:03:14.000-08:00
Signed-off-by: Derek McGowan &lt;derek@mcgstyle.net&gt;
diff --git a/archive/tar.go b/archive/tar.go
@@ -82,6 +82,8 @@ const (
 	// whiteoutOpaqueDir file means directory has been made opaque - meaning
 	// readdir calls to this directory do not follow to lower layers.
 	whiteoutOpaqueDir = whiteoutMetaPrefix + ".opq"
+
+	paxSchilyXattr = "SCHILY.xattrs."
 )
 
 // Apply applies a tar stream of an OCI style diff tar.
@@ -388,9 +390,10 @@ func (cw *changeWriter) HandleChange(k fs.ChangeKind, p string, f os.FileInfo, e
 		if capability, err := getxattr(source, "security.capability"); err != nil {
 			return errors.Wrap(err, "failed to get capabilities xattr")
 		} else if capability != nil {
-			hdr.Xattrs = map[string]string{
-				"security.capability": string(capability),
+			if hdr.PAXRecords == nil {
+				hdr.PAXRecords = map[string]string{}
 			}
+			hdr.PAXRecords[paxSchilyXattr+"security.capability"] = string(capability)
 		}
 
 		if err := cw.tw.WriteHeader(hdr); err != nil {
@@ -509,13 +512,16 @@ func createTarFile(ctx context.Context, path, extractDir string, hdr *tar.Header
 		}
 	}
 
-	for key, value := range hdr.Xattrs {
-		if err := setxattr(path, key, value); err != nil {
-			if errors.Cause(err) == syscall.ENOTSUP {
-				log.G(ctx).WithError(err).Warnf("ignored xattr %s in archive", key)
-				continue
+	for key, value := range hdr.PAXRecords {
+		if strings.HasPrefix(key, paxSchilyXattr) {
+			key = key[len(paxSchilyXattr):]
+			if err := setxattr(path, key, value); err != nil {
+				if errors.Cause(err) == syscall.ENOTSUP {
+					log.G(ctx).WithError(err).Warnf("ignored xattr %s in archive", key)
+					continue
+				}
+				return err
 			}
-			return err
 		}
 	}
 

Original file line number	Diff line number	Diff line change
`@@ -82,6 +82,8 @@ const (`
`82`	`82`	`// whiteoutOpaqueDir file means directory has been made opaque - meaning`
`83`	`83`	`// readdir calls to this directory do not follow to lower layers.`
`84`	`84`	`whiteoutOpaqueDir = whiteoutMetaPrefix + ".opq"`
	`85`	`+`
	`86`	`+ paxSchilyXattr = "SCHILY.xattrs."`
`85`	`87`	`)`
`86`	`88`
`87`	`89`	`// Apply applies a tar stream of an OCI style diff tar.`
`@@ -388,9 +390,10 @@ func (cw *changeWriter) HandleChange(k fs.ChangeKind, p string, f os.FileInfo, e`
`388`	`390`	`if capability, err := getxattr(source, "security.capability"); err != nil {`
`389`	`391`	`return errors.Wrap(err, "failed to get capabilities xattr")`
`390`	`392`	`} else if capability != nil {`
`391`		`- hdr.Xattrs = map[string]string{`
`392`		`- "security.capability": string(capability),`
	`393`	`+ if hdr.PAXRecords == nil {`
	`394`	`+ hdr.PAXRecords = map[string]string{}`
`393`	`395`	`}`
	`396`	`+ hdr.PAXRecords[paxSchilyXattr+"security.capability"] = string(capability)`
`394`	`397`	`}`
`395`	`398`
`396`	`399`	`if err := cw.tw.WriteHeader(hdr); err != nil {`
`@@ -509,13 +512,16 @@ func createTarFile(ctx context.Context, path, extractDir string, hdr *tar.Header`
`509`	`512`	`}`
`510`	`513`	`}`
`511`	`514`
`512`		`- for key, value := range hdr.Xattrs {`
`513`		`- if err := setxattr(path, key, value); err != nil {`
`514`		`- if errors.Cause(err) == syscall.ENOTSUP {`
`515`		`- log.G(ctx).WithError(err).Warnf("ignored xattr %s in archive", key)`
`516`		`- continue`
	`515`	`+ for key, value := range hdr.PAXRecords {`
	`516`	`+ if strings.HasPrefix(key, paxSchilyXattr) {`
	`517`	`+ key = key[len(paxSchilyXattr):]`
	`518`	`+ if err := setxattr(path, key, value); err != nil {`
	`519`	`+ if errors.Cause(err) == syscall.ENOTSUP {`
	`520`	`+ log.G(ctx).WithError(err).Warnf("ignored xattr %s in archive", key)`
	`521`	`+ continue`
	`522`	`+ }`
	`523`	`+ return err`
`517`	`524`	`}`
`518`		`- return err`
`519`	`525`	`}`
`520`	`526`	`}`
`521`	`527`