kubenetworks/kubevpn

package cp

import (
    "archive/tar"
    "io"
    "os"
)

// copy from another real file
func copyFromLink(fileHeaderList []tar.Header, currFile tar.Header, genDstFilename func(headerName string) localPath) error {
    for _, t := range fileHeaderList {
        if t.Name == currFile.Linkname {
            // handle it recursive if linkA --> linkB --> originFile
            return copyFromLink(fileHeaderList, t, genDstFilename)
        }
    }

    var err error
    var r, w *os.File
    // read from origin file
    r, err = os.OpenFile(genDstFilename(currFile.Linkname).String(), os.O_RDONLY, 0644)
    if err != nil {
        return err
    }

    // write to current file
    w, err = os.OpenFile(genDstFilename(currFile.Name).String(), os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
    if err != nil {
        return err
    }
    _, err = io.Copy(w, r)
    if closeErr := w.Close(); closeErr != nil && err == nil {
        err = closeErr
    }
    return err
}