Mysterious bug with tty.ReadStream since v0.11.x (0.12 as well)

[jshkurti]

Hello,

I'm working on a project which requires me to spawn a pseudo-terminal (native addon) and then handle its file descriptor to my NodeJS code for some remote terminal stuff purposes.
It works like a charm with node 0.10.x but it doesn't with 0.11.x nor 0.12.

Here's my C common code :
(For readability purposes I removed all error checking but there's none, all syscalls work fine)

#define _XOPEN_SOURCE 600
#include <stdlib.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <stdio.h>
#include <sys/select.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <string.h>
#include <signal.h>

static void handler_sigchld(int status) {
  wait(&status);
  printf("Child process died with status: %d\n", status);
}

static int get_pty(void) {
  int fdm, fds;

  fdm = posix_openpt(O_RDWR);
  grantpt(fdm);
  unlockpt(fdm);
  fds = open(ptsname(fdm), O_RDWR);
  signal(SIGCHLD, handler_sigchld);
  if (fork() == 0) {
    dup2(fds, 0);
    dup2(fds, 1);
    dup2(fds, 2);
    setsid();
    ioctl(0, TIOCSCTTY, 1);
    {
      char **child_av = (char**)malloc(sizeof(char*) * 2);
      child_av[0] = (char*)"/bin/sh";
      child_av[1] = (char*)NULL;
      execv(child_av[0], child_av);
      return (-1);
    }
  }
  return (fdm);
}

Here's my node 0.10.32 C++ wrap :

#include <node.h>
#include <v8.h>

using namespace v8;

Handle<Value> OpenPty(const Arguments& args) {
  HandleScope scope;

  int fd_master = get_pty();
  Local<Number> num = Number::New(fd_master);

  return scope.Close(num);
}

void init(Handle<Object> exports) {
  exports->Set(String::NewSymbol("posix_openpt"),
               FunctionTemplate::New(OpenPty)->GetFunction());
}

NODE_MODULE(posix_openpt, init)

Node 0.11.14 C++ wrap :

#include <node.h>

using namespace v8;

void OpenPty(const FunctionCallbackInfo<Value>& args) {
  Isolate* isolate = Isolate::GetCurrent();
  HandleScope scope(isolate);

  int fd_master = get_pty();

  Local<Number> ret = Number::New(isolate, fd_master);
  args.GetReturnValue().Set(ret);
}

void init(Handle<Object> exports) {
  NODE_SET_METHOD(exports, "posix_openpt", OpenPty);
}

NODE_MODULE(posix_openpt, init)

Compilation via node-gyp also works fine for both node versions.

And finally here's my JS code :

var tty = require('tty');
var pty = require('./build/Release/posix_openpt.node');

var fd = pty.posix_openpt();
var term = new tty.ReadStream(fd);

console.log('FD: ' + fd);

term.write('ls -l\n');
term.pipe(process.stdout);

Result with node 0.10.32 (as expected we got output from our pseudo-terminal) :

Result with node 0.11.14 (we got nothing):

My stream doesn't respond to anything, I've also tried piping stdin into it.

Any thoughts on how and why node updates would affect this behaviour ?

Thanks.

[Unitech]

Same error here with https://github.com/chjj/pty.js with Node 0.11.x and a zombie process appears

[trevnorris]

On the side, your v0.11 can be simplified to the following:

#include <node.h>

using namespace v8;

void OpenPty(const FunctionCallbackInfo<Value>& args) {
  args.GetReturnValue().Set(static_cast<uint32_t>(get_pty()));
}

void init(Handle<Object> exports) {
  NODE_SET_METHOD(exports, "posix_openpt", OpenPty);
}

NODE_MODULE(posix_openpt, init)

[jasnell]

@jshkurti ... I know it's been a while, but is this still an issue for you? Have you tested with v0.12.5 or io.js?