package dockerfile import ( "fmt" "os" "path/filepath" "strings" "github.com/docker/docker/pkg/system" ) // normaliseDest normalises the destination of a COPY/ADD command in a // platform semantically consistent way. func normaliseDest(cmdName, workingDir, requested string) (string, error) { dest := filepath.FromSlash(requested) endsInSlash := strings.HasSuffix(dest, string(os.PathSeparator)) // We are guaranteed that the working directory is already consistent, // However, Windows also has, for now, the limitation that ADD/COPY can // only be done to the system drive, not any drives that might be present // as a result of a bind mount. // // So... if the path requested is Linux-style absolute (/foo or \\foo), // we assume it is the system drive. If it is a Windows-style absolute // (DRIVE:\\foo), error if DRIVE is not C. And finally, ensure we // strip any configured working directories drive letter so that it // can be subsequently legitimately converted to a Windows volume-style // pathname. // Not a typo - filepath.IsAbs, not system.IsAbs on this next check as // we only want to validate where the DriveColon part has been supplied. if filepath.IsAbs(dest) { if strings.ToUpper(string(dest[0])) != "C" { return "", fmt.Errorf("Windows does not support %s with a destinations not on the system drive (C:)", cmdName) } dest = dest[2:] // Strip the drive letter } // Cannot handle relative where WorkingDir is not the system drive. if len(workingDir) > 0 { if ((len(workingDir) > 1) && !system.IsAbs(workingDir[2:])) || (len(workingDir) == 1) { return "", fmt.Errorf("Current WorkingDir %s is not platform consistent", workingDir) } if !system.IsAbs(dest) { if string(workingDir[0]) != "C" { return "", fmt.Errorf("Windows does not support %s with relative paths when WORKDIR is not the system drive", cmdName) } dest = filepath.Join(string(os.PathSeparator), workingDir[2:], dest) // Make sure we preserve any trailing slash if endsInSlash { dest += string(os.PathSeparator) } } } return dest, nil }