53 lines
1.5 KiB
Go
53 lines
1.5 KiB
Go
/*
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Copyright The containerd Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package archive
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import (
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"archive/tar"
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"os"
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"path/filepath"
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"strings"
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"golang.org/x/sys/unix"
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)
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// OverlayConvertWhiteout converts whiteout files for overlay.
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func OverlayConvertWhiteout(hdr *tar.Header, path string) (bool, error) {
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base := filepath.Base(path)
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dir := filepath.Dir(path)
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// if a directory is marked as opaque, we need to translate that to overlay
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if base == whiteoutOpaqueDir {
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// don't write the file itself
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return false, unix.Setxattr(dir, "trusted.overlay.opaque", []byte{'y'}, 0)
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}
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// if a file was deleted and we are using overlay, we need to create a character device
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if strings.HasPrefix(base, whiteoutPrefix) {
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originalBase := base[len(whiteoutPrefix):]
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originalPath := filepath.Join(dir, originalBase)
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if err := unix.Mknod(originalPath, unix.S_IFCHR, 0); err != nil {
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return false, err
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}
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// don't write the file itself
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return false, os.Chown(originalPath, hdr.Uid, hdr.Gid)
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}
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return true, nil
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}
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