// Run will launch the stage2 binary with the desired settings and execute the
// specified command. It will return once the stage2 has been started.
func (l *Launcher) Run(cmdargs ...string) (*os.Process, error) {
args, extraFiles := l.generateArgs(cmdargs)
// get the executable path to ourself
self, err := os.Readlink("/proc/self/exe")
if err != nil {
return nil, err
}
// Create and initialize the spawnwer.
cmd := exec.Command(self, args...)
cmd.ExtraFiles = extraFiles
if l.Stdin != nil {
cmd.Stdin = l.Stdin
}
if l.Stdout != nil {
cmd.Stdout = l.Stdout
}
if l.Stderr != nil {
cmd.Stderr = l.Stderr
}
// The spawner keys off this environment variable to know when it is supposed
// to run and take over execution.
cmd.Env = []string{
"SPAWNER_INTERCEPT=1",
}
// tty handling
if str.IsTerminal(l.Stdin) {
// Include setting the controlling tty, and close stdin (the slave pty)
// after the command is started.
cmd.SysProcAttr = &syscall.SysProcAttr{Setctty: true, Setsid: true}
l.postStart = append(l.postStart, func() { l.Stdin.Close() })
} else {
cmd.SysProcAttr = &syscall.SysProcAttr{Setsid: true}
}
// Start the container.
if err := cmd.Start(); err != nil {
return nil, err
}
// Run any postStart funcs, just to cleanup
for _, f := range l.postStart {
f()
}
// Wait for the command to ensure the process is reaped when its done.
if l.Detach {
go cmd.Wait()
}
return cmd.Process, nil
}
func main() {
for _, label := range []string{
"stdin", "stdout", "stderr",
} {
var fh *os.File
switch label {
case "stdin":
fh = os.Stdin
case "stdout":
fh = os.Stdout
case "stderr":
fh = os.Stderr
default:
panic("unknown label")
}
if target.IsTerminal(fh) {
fmt.Printf("%s is a terminal :)\n", label)
} else {
fmt.Printf("%s is not a terminal :(\n", label)
}
}
}