diff --git a/pkg/chrootarchive/archive.go b/pkg/chrootarchive/archive.go index ae15a2a54d..17d3739d1a 100644 --- a/pkg/chrootarchive/archive.go +++ b/pkg/chrootarchive/archive.go @@ -1,7 +1,6 @@ package chrootarchive import ( - "bytes" "encoding/json" "flag" "fmt" @@ -9,7 +8,6 @@ import ( "os" "path/filepath" "runtime" - "strings" "syscall" "github.com/docker/docker/pkg/archive" @@ -28,11 +26,14 @@ func chroot(path string) error { func untar() { runtime.LockOSThread() flag.Parse() - if err := chroot(flag.Arg(0)); err != nil { + + var options *archive.TarOptions + + if err := json.Unmarshal([]byte(os.Getenv("OPT")), &options); err != nil { fatal(err) } - var options *archive.TarOptions - if err := json.NewDecoder(strings.NewReader(flag.Arg(1))).Decode(&options); err != nil { + + if err := chroot(flag.Arg(0)); err != nil { fatal(err) } if err := archive.Unpack(os.Stdin, "/", options); err != nil { @@ -54,27 +55,32 @@ func Untar(tarArchive io.Reader, dest string, options *archive.TarOptions) error options.ExcludePatterns = []string{} } - var ( - buf bytes.Buffer - enc = json.NewEncoder(&buf) - ) - if err := enc.Encode(options); err != nil { - return fmt.Errorf("Untar json encode: %v", err) - } + dest = filepath.Clean(dest) if _, err := os.Stat(dest); os.IsNotExist(err) { if err := os.MkdirAll(dest, 0777); err != nil { return err } } - dest = filepath.Clean(dest) + + // We can't pass the exclude list directly via cmd line + // because we easily overrun the shell max argument list length + // when the full image list is passed (e.g. when this is used + // by `docker load`). Instead we will add the JSON marshalled + // and placed in the env, which has significantly larger + // max size + data, err := json.Marshal(options) + if err != nil { + return fmt.Errorf("Untar json encode: %v", err) + } decompressedArchive, err := archive.DecompressStream(tarArchive) if err != nil { return err } defer decompressedArchive.Close() - cmd := reexec.Command("docker-untar", dest, buf.String()) + cmd := reexec.Command("docker-untar", dest) cmd.Stdin = decompressedArchive + cmd.Env = append(cmd.Env, fmt.Sprintf("OPT=%s", data)) out, err := cmd.CombinedOutput() if err != nil { return fmt.Errorf("Untar %s %s", err, out)