diff options
Diffstat (limited to 'runsc/sandbox/sandbox.go')
| -rw-r--r-- | runsc/sandbox/sandbox.go | 46 |
1 files changed, 28 insertions, 18 deletions
diff --git a/runsc/sandbox/sandbox.go b/runsc/sandbox/sandbox.go index 6c1b39be7..be68e864f 100644 --- a/runsc/sandbox/sandbox.go +++ b/runsc/sandbox/sandbox.go @@ -351,6 +351,15 @@ func (s *Sandbox) createSandboxProcess(spec *specs.Spec, conf *boot.Config, bund nextFD++ } + // The current process' stdio must be passed to the application via the + // --stdio-fds flag. The stdio of the sandbox process itself must not + // be connected to the same FDs, otherwise we risk leaking sandbox + // errors to the application, so we set the sandbox stdio to nil, + // causing them to read/write from the null device. + cmd.Stdin = nil + cmd.Stdout = nil + cmd.Stderr = nil + // If the console control socket file is provided, then create a new // pty master/slave pair and set the TTY on the sandbox process. if consoleSocket != "" { @@ -364,21 +373,13 @@ func (s *Sandbox) createSandboxProcess(spec *specs.Spec, conf *boot.Config, bund } defer tty.Close() - // Ideally we would set the sandbox stdin to this process' - // stdin, but for some reason Docker does not like that (it - // never calls `runsc start`). Instead we set stdio to the - // console TTY, but note that this is distinct from the - // container stdio, which is passed via the flags below. - cmd.Stdin = tty - cmd.Stdout = tty - cmd.Stderr = tty - // Set the TTY as a controlling TTY on the sandbox process. // Note that the Ctty field must be the FD of the TTY in the - // *new* process, not this process. Since we set the TTY to + // *new* process, not this process. Since we are about to + // assign the TTY to nextFD, we can use that value here. // stdin, we can use FD 0 here. cmd.SysProcAttr.Setctty = true - cmd.SysProcAttr.Ctty = 0 + cmd.SysProcAttr.Ctty = nextFD // Pass the tty as all stdio fds to sandbox. for i := 0; i < 3; i++ { @@ -386,14 +387,15 @@ func (s *Sandbox) createSandboxProcess(spec *specs.Spec, conf *boot.Config, bund cmd.Args = append(cmd.Args, "--stdio-fds="+strconv.Itoa(nextFD)) nextFD++ } - } else { - // Connect the sandbox process to this process's stdios. Note - // that this is distinct from the container's stdio, which is - // passed by the flags below. - cmd.Stdin = os.Stdin - cmd.Stdout = os.Stdout - cmd.Stderr = os.Stderr + if conf.Debug { + // If debugging, send the boot process stdio to the + // TTY, so that it is easier to find. + cmd.Stdin = tty + cmd.Stdout = tty + cmd.Stderr = tty + } + } else { // If not using a console, pass our current stdio as the // container stdio via flags. for _, f := range []*os.File{os.Stdin, os.Stdout, os.Stderr} { @@ -401,6 +403,14 @@ func (s *Sandbox) createSandboxProcess(spec *specs.Spec, conf *boot.Config, bund cmd.Args = append(cmd.Args, "--stdio-fds="+strconv.Itoa(nextFD)) nextFD++ } + + if conf.Debug { + // If debugging, send the boot process stdio to the + // this process' stdio, so that is is easier to find. + cmd.Stdin = os.Stdin + cmd.Stdout = os.Stdout + cmd.Stderr = os.Stderr + } } // Detach from this session, otherwise cmd will get SIGHUP and SIGCONT |