d26587c725
These strings were resolved using the user information on the host filesystem and were decreasing reproducibility. For moby/buildkit issue 3688 Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
83 lines
3.0 KiB
Go
83 lines
3.0 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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/*
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Portions from https://github.com/moby/moby/blob/v23.0.1/pkg/archive/archive.go#L419-L464
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Copyright (C) Docker/Moby authors.
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Licensed under the Apache License, Version 2.0
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NOTICE: https://github.com/moby/moby/blob/v23.0.1/NOTICE
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*/
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package tarheader
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import (
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"archive/tar"
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"os"
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)
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// nosysFileInfo hides the system-dependent info of the wrapped FileInfo to
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// prevent tar.FileInfoHeader from introspecting it and potentially calling into
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// glibc.
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//
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// From https://github.com/moby/moby/blob/v23.0.1/pkg/archive/archive.go#L419-L434 .
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type nosysFileInfo struct {
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os.FileInfo
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}
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func (fi nosysFileInfo) Sys() interface{} {
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// A Sys value of type *tar.Header is safe as it is system-independent.
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// The tar.FileInfoHeader function copies the fields into the returned
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// header without performing any OS lookups.
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if sys, ok := fi.FileInfo.Sys().(*tar.Header); ok {
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return sys
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}
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return nil
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}
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// sysStat, if non-nil, populates hdr from system-dependent fields of fi.
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//
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// From https://github.com/moby/moby/blob/v23.0.1/pkg/archive/archive.go#L436-L437 .
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var sysStat func(fi os.FileInfo, hdr *tar.Header) error
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// FileInfoHeaderNoLookups creates a partially-populated tar.Header from fi.
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//
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// Compared to the archive/tar.FileInfoHeader function, this function is safe to
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// call from a chrooted process as it does not populate fields which would
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// require operating system lookups. It behaves identically to
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// tar.FileInfoHeader when fi is a FileInfo value returned from
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// tar.Header.FileInfo().
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//
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// When fi is a FileInfo for a native file, such as returned from os.Stat() and
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// os.Lstat(), the returned Header value differs from one returned from
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// tar.FileInfoHeader in the following ways. The Uname and Gname fields are not
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// set as OS lookups would be required to populate them. The AccessTime and
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// ChangeTime fields are not currently set (not yet implemented) although that
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// is subject to change. Callers which require the AccessTime or ChangeTime
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// fields to be zeroed should explicitly zero them out in the returned Header
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// value to avoid any compatibility issues in the future.
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//
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// From https://github.com/moby/moby/blob/v23.0.1/pkg/archive/archive.go#L439-L464 .
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func FileInfoHeaderNoLookups(fi os.FileInfo, link string) (*tar.Header, error) {
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hdr, err := tar.FileInfoHeader(nosysFileInfo{fi}, link)
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if err != nil {
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return nil, err
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}
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if sysStat != nil {
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return hdr, sysStat(fi, hdr)
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}
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return hdr, nil
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}
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