145 lines
3.7 KiB
Go
145 lines
3.7 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 fs
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import (
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"io"
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"os"
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"syscall"
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"github.com/containerd/continuity/sysx"
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"github.com/pkg/errors"
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"golang.org/x/sys/unix"
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)
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func copyFileInfo(fi os.FileInfo, name string) error {
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st := fi.Sys().(*syscall.Stat_t)
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if err := os.Lchown(name, int(st.Uid), int(st.Gid)); err != nil {
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if os.IsPermission(err) {
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// Normally if uid/gid are the same this would be a no-op, but some
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// filesystems may still return EPERM... for instance NFS does this.
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// In such a case, this is not an error.
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if dstStat, err2 := os.Lstat(name); err2 == nil {
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st2 := dstStat.Sys().(*syscall.Stat_t)
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if st.Uid == st2.Uid && st.Gid == st2.Gid {
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err = nil
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}
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}
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}
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if err != nil {
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return errors.Wrapf(err, "failed to chown %s", name)
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}
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}
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if (fi.Mode() & os.ModeSymlink) != os.ModeSymlink {
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if err := os.Chmod(name, fi.Mode()); err != nil {
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return errors.Wrapf(err, "failed to chmod %s", name)
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}
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}
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timespec := []unix.Timespec{unix.Timespec(StatAtime(st)), unix.Timespec(StatMtime(st))}
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if err := unix.UtimesNanoAt(unix.AT_FDCWD, name, timespec, unix.AT_SYMLINK_NOFOLLOW); err != nil {
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return errors.Wrapf(err, "failed to utime %s", name)
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}
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return nil
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}
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const maxSSizeT = int64(^uint(0) >> 1)
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func copyFileContent(dst, src *os.File) error {
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st, err := src.Stat()
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if err != nil {
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return errors.Wrap(err, "unable to stat source")
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}
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size := st.Size()
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first := true
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srcFd := int(src.Fd())
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dstFd := int(dst.Fd())
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for size > 0 {
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// Ensure that we are never trying to copy more than SSIZE_MAX at a
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// time and at the same time avoids overflows when the file is larger
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// than 4GB on 32-bit systems.
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var copySize int
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if size > maxSSizeT {
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copySize = int(maxSSizeT)
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} else {
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copySize = int(size)
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}
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n, err := unix.CopyFileRange(srcFd, nil, dstFd, nil, copySize, 0)
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if err != nil {
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if (err != unix.ENOSYS && err != unix.EXDEV) || !first {
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return errors.Wrap(err, "copy file range failed")
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}
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buf := bufferPool.Get().(*[]byte)
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_, err = io.CopyBuffer(dst, src, *buf)
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bufferPool.Put(buf)
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return errors.Wrap(err, "userspace copy failed")
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}
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first = false
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size -= int64(n)
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}
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return nil
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}
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func copyXAttrs(dst, src string, xeh XAttrErrorHandler) error {
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xattrKeys, err := sysx.LListxattr(src)
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if err != nil {
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e := errors.Wrapf(err, "failed to list xattrs on %s", src)
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if xeh != nil {
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e = xeh(dst, src, "", e)
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}
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return e
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}
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for _, xattr := range xattrKeys {
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data, err := sysx.LGetxattr(src, xattr)
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if err != nil {
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e := errors.Wrapf(err, "failed to get xattr %q on %s", xattr, src)
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if xeh != nil {
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if e = xeh(dst, src, xattr, e); e == nil {
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continue
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}
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}
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return e
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}
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if err := sysx.LSetxattr(dst, xattr, data, 0); err != nil {
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e := errors.Wrapf(err, "failed to set xattr %q on %s", xattr, dst)
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if xeh != nil {
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if e = xeh(dst, src, xattr, e); e == nil {
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continue
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}
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}
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return e
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}
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}
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return nil
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}
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func copyDevice(dst string, fi os.FileInfo) error {
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st, ok := fi.Sys().(*syscall.Stat_t)
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if !ok {
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return errors.New("unsupported stat type")
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}
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return unix.Mknod(dst, uint32(fi.Mode()), int(st.Rdev))
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}
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