func run() int {
flag.Parse()
runtime := flag.Args()[1] // e.g. runc
dir := flag.Args()[2] // bundlePath for run, processPath for exec
containerId := flag.Args()[3]
signals := make(chan os.Signal, 100)
signal.Notify(signals, syscall.SIGCHLD)
fd3 := os.NewFile(3, "/proc/self/fd/3")
logFile := fmt.Sprintf("/proc/%d/fd/4", os.Getpid())
logFD := os.NewFile(4, "/proc/self/fd/4")
syncPipe := os.NewFile(5, "/proc/self/fd/5")
pidFilePath := filepath.Join(dir, "pidfile")
stdin, stdout, stderr, winsz := openPipes(dir)
syncPipe.Write([]byte{0})
var runcStartCmd *exec.Cmd
if *tty {
ttySlave := setupTty(stdin, stdout, pidFilePath, winsz, garden.WindowSize{Rows: *rows, Columns: *cols})
runcStartCmd = exec.Command(runtime, "-debug", "-log", logFile, "exec", "-d", "-tty", "-console", ttySlave.Name(), "-p", fmt.Sprintf("/proc/%d/fd/0", os.Getpid()), "-pid-file", pidFilePath, containerId)
} else {
runcStartCmd = exec.Command(runtime, "-debug", "-log", logFile, "exec", "-p", fmt.Sprintf("/proc/%d/fd/0", os.Getpid()), "-d", "-pid-file", pidFilePath, containerId)
runcStartCmd.Stdin = stdin
runcStartCmd.Stdout = stdout
runcStartCmd.Stderr = stderr
}
// we need to be the subreaper so we can wait on the detached container process
system.SetSubreaper(os.Getpid())
if err := runcStartCmd.Start(); err != nil {
fd3.Write([]byte{2})
return 2
}
var status syscall.WaitStatus
var rusage syscall.Rusage
_, err := syscall.Wait4(runcStartCmd.Process.Pid, &status, 0, &rusage)
check(err) // Start succeeded but Wait4 failed, this can only be a programmer error
logFD.Close() // No more logs from runc so close fd
fd3.Write([]byte{byte(status.ExitStatus())})
if status.ExitStatus() != 0 {
return 3 // nothing to wait for, container didn't launch
}
containerPid, err := parsePid(pidFilePath)
check(err)
return waitForContainerToExit(dir, containerPid, signals)
}
// newSignalHandler returns a signal handler for processing SIGCHLD and SIGWINCH signals
// while still forwarding all other signals to the process.
func newSignalHandler(tty *tty, enableSubreaper bool) *signalHandler {
if enableSubreaper {
// set us as the subreaper before registering the signal handler for the container
if err := system.SetSubreaper(1); err != nil {
logrus.Warn(err)
}
}
// ensure that we have a large buffer size so that we do not miss any signals
// incase we are not processing them fast enough.
s := make(chan os.Signal, signalBufferSize)
// handle all signals for the process.
signal.Notify(s)
return &signalHandler{
tty: tty,
signals: s,
}
}