pkg/system: return rich errors from L(g|s)etxattr

Signed-off-by: Cory Snider <csnider@mirantis.com>

pkg/archive/archive.go

@@ -757,26 +757,26 @@ func createTarFile(path, extractDir string, hdr *tar.Header, reader io.Reader, L
 		}
 	}
 
-	var errors []string
+	var xattrErrs []string
 	for key, value := range hdr.Xattrs {
 		if err := system.Lsetxattr(path, key, []byte(value), 0); err != nil {
-			if err == syscall.ENOTSUP || err == syscall.EPERM {
+			if errors.Is(err, syscall.ENOTSUP) || errors.Is(err, syscall.EPERM) {
 				// We ignore errors here because not all graphdrivers support
 				// xattrs *cough* old versions of AUFS *cough*. However only
 				// ENOTSUP should be emitted in that case, otherwise we still
 				// bail.
 				// EPERM occurs if modifying xattrs is not allowed. This can
 				// happen when running in userns with restrictions (ChromeOS).
-				errors = append(errors, err.Error())
+				xattrErrs = append(xattrErrs, err.Error())
 				continue
 			}
 			return err
 		}
 	}
 
-	if len(errors) > 0 {
+	if len(xattrErrs) > 0 {
 		logrus.WithFields(logrus.Fields{
-			"errors": errors,
+			"errors": xattrErrs,
 		}).Warn("ignored xattrs in archive: underlying filesystem doesn't support them")
 	}
 

pkg/system/xattrs_linux.go

@@ -1,11 +1,19 @@
 package system // import "github.com/docker/docker/pkg/system"
 
-import "golang.org/x/sys/unix"
+import (
+	"io/fs"
+
+	"golang.org/x/sys/unix"
+)
 
 // Lgetxattr retrieves the value of the extended attribute identified by attr
 // and associated with the given path in the file system.
 // It will returns a nil slice and nil error if the xattr is not set.
 func Lgetxattr(path string, attr string) ([]byte, error) {
+	pathErr := func(err error) ([]byte, error) {
+		return nil, &fs.PathError{Op: "lgetxattr", Path: path, Err: err}
+	}
+
 	// Start with a 128 length byte array
 	dest := make([]byte, 128)
 	sz, errno := unix.Lgetxattr(path, attr, dest)
@@ -14,7 +22,7 @@ func Lgetxattr(path string, attr string) ([]byte, error) {
 		// Buffer too small, use zero-sized buffer to get the actual size
 		sz, errno = unix.Lgetxattr(path, attr, []byte{})
 		if errno != nil {
-			return nil, errno
+			return pathErr(errno)
 		}
 		dest = make([]byte, sz)
 		sz, errno = unix.Lgetxattr(path, attr, dest)
@@ -24,7 +32,7 @@ func Lgetxattr(path string, attr string) ([]byte, error) {
 	case errno == unix.ENODATA:
 		return nil, nil
 	case errno != nil:
-		return nil, errno
+		return pathErr(errno)
 	}
 
 	return dest[:sz], nil
@@ -33,5 +41,9 @@ func Lgetxattr(path string, attr string) ([]byte, error) {
 // Lsetxattr sets the value of the extended attribute identified by attr
 // and associated with the given path in the file system.
 func Lsetxattr(path string, attr string, data []byte, flags int) error {
-	return unix.Lsetxattr(path, attr, data, flags)
+	err := unix.Lsetxattr(path, attr, data, flags)
+	if err != nil {
+		return &fs.PathError{Op: "lsetxattr", Path: path, Err: err}
+	}
+	return nil
 }