package fs import ( "io" "os" "syscall" "github.com/containerd/continuity/sysx" "github.com/pkg/errors" "golang.org/x/sys/unix" ) func copyFileInfo(fi os.FileInfo, name string) error { st := fi.Sys().(*syscall.Stat_t) if err := os.Lchown(name, int(st.Uid), int(st.Gid)); err != nil { if os.IsPermission(err) { // Normally if uid/gid are the same this would be a no-op, but some // filesystems may still return EPERM... for instance NFS does this. // In such a case, this is not an error. if dstStat, err2 := os.Lstat(name); err2 == nil { st2 := dstStat.Sys().(*syscall.Stat_t) if st.Uid == st2.Uid && st.Gid == st2.Gid { err = nil } } } if err != nil { return errors.Wrapf(err, "failed to chown %s", name) } } if (fi.Mode() & os.ModeSymlink) != os.ModeSymlink { if err := os.Chmod(name, fi.Mode()); err != nil { return errors.Wrapf(err, "failed to chmod %s", name) } } timespec := []unix.Timespec{unix.Timespec(StatAtime(st)), unix.Timespec(StatMtime(st))} if err := unix.UtimesNanoAt(unix.AT_FDCWD, name, timespec, unix.AT_SYMLINK_NOFOLLOW); err != nil { return errors.Wrapf(err, "failed to utime %s", name) } return nil } func copyFileContent(dst, src *os.File) error { st, err := src.Stat() if err != nil { return errors.Wrap(err, "unable to stat source") } size := st.Size() first := true srcFd := int(src.Fd()) dstFd := int(dst.Fd()) for size > 0 { n, err := unix.CopyFileRange(srcFd, nil, dstFd, nil, int(size), 0) if err != nil { if (err != unix.ENOSYS && err != unix.EXDEV) || !first { return errors.Wrap(err, "copy file range failed") } buf := bufferPool.Get().(*[]byte) _, err = io.CopyBuffer(dst, src, *buf) bufferPool.Put(buf) return errors.Wrap(err, "userspace copy failed") } first = false size -= int64(n) } return nil } func copyXAttrs(dst, src string) error { xattrKeys, err := sysx.LListxattr(src) if err != nil { return errors.Wrapf(err, "failed to list xattrs on %s", src) } for _, xattr := range xattrKeys { data, err := sysx.LGetxattr(src, xattr) if err != nil { return errors.Wrapf(err, "failed to get xattr %q on %s", xattr, src) } if err := sysx.LSetxattr(dst, xattr, data, 0); err != nil { return errors.Wrapf(err, "failed to set xattr %q on %s", xattr, dst) } } return nil } func copyDevice(dst string, fi os.FileInfo) error { st, ok := fi.Sys().(*syscall.Stat_t) if !ok { return errors.New("unsupported stat type") } return unix.Mknod(dst, uint32(fi.Mode()), int(st.Rdev)) }