Merge pull request #6844 from bfredl/channel

channels: support buffered output and bytes sockets/stdio

32 files changed, 1503 insertions, 1095 deletions

diff --git a/src/nvim/api/ui.c b/src/nvim/api/ui.c
index afbee09c1c..a9eaccfac5 100644
--- a/src/nvim/api/ui.c
+++ b/src/nvim/api/ui.c
@@ -252,7 +252,7 @@ static void remote_ui_flush(UI *ui)
 {
   UIData *data = ui->data;
   if (data->buffer.size > 0) {
-    channel_send_event(data->channel_id, "redraw", data->buffer);
+    rpc_send_event(data->channel_id, "redraw", data->buffer);
     data->buffer = (Array)ARRAY_DICT_INIT;
   }
 }
diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index d2b0e329c9..f4ccf07bec 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -721,7 +721,7 @@ void nvim_subscribe(uint64_t channel_id, String event)
   char e[METHOD_MAXLEN + 1];
   memcpy(e, event.data, length);
   e[length] = NUL;
-  channel_subscribe(channel_id, e);
+  rpc_subscribe(channel_id, e);
 }
 
 /// Unsubscribes to event broadcasts
@@ -737,7 +737,7 @@ void nvim_unsubscribe(uint64_t channel_id, String event)
   char e[METHOD_MAXLEN + 1];
   memcpy(e, event.data, length);
   e[length] = NUL;
-  channel_unsubscribe(channel_id, e);
+  rpc_unsubscribe(channel_id, e);
 }
 
 Integer nvim_get_color_by_name(String name)
diff --git a/src/nvim/buffer_defs.h b/src/nvim/buffer_defs.h
index 559dffb945..f1cbcb2627 100644
--- a/src/nvim/buffer_defs.h
+++ b/src/nvim/buffer_defs.h
@@ -603,6 +603,7 @@ struct file_buffer {
   char_u *b_p_bt;               ///< 'buftype'
   int b_has_qf_entry;           ///< quickfix exists for buffer
   int b_p_bl;                   ///< 'buflisted'
+  long b_p_channel;             ///< 'channel'
   int b_p_cin;                  ///< 'cindent'
   char_u *b_p_cino;             ///< 'cinoptions'
   char_u *b_p_cink;             ///< 'cinkeys'
diff --git a/src/nvim/channel.c b/src/nvim/channel.c
new file mode 100644
index 0000000000..40af470bde
--- /dev/null
+++ b/src/nvim/channel.c
@@ -0,0 +1,752 @@
+// This is an open source non-commercial project. Dear PVS-Studio, please check
+// it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+
+#include "nvim/api/ui.h"
+#include "nvim/channel.h"
+#include "nvim/eval.h"
+#include "nvim/event/socket.h"
+#include "nvim/msgpack_rpc/channel.h"
+#include "nvim/msgpack_rpc/server.h"
+#include "nvim/os/shell.h"
+#include "nvim/path.h"
+#include "nvim/ascii.h"
+
+static bool did_stdio = false;
+PMap(uint64_t) *channels = NULL;
+
+/// next free id for a job or rpc channel
+/// 1 is reserved for stdio channel
+/// 2 is reserved for stderr channel
+static uint64_t next_chan_id = CHAN_STDERR+1;
+
+
+typedef struct {
+  Channel *chan;
+  Callback *callback;
+  const char *type;
+  list_T *received;
+  int status;
+} ChannelEvent;
+
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# include "channel.c.generated.h"
+#endif
+/// Teardown the module
+void channel_teardown(void)
+{
+  if (!channels) {
+    return;
+  }
+
+  Channel *channel;
+
+  map_foreach_value(channels, channel, {
+    channel_close(channel->id, kChannelPartAll, NULL);
+  });
+}
+
+/// Closes a channel
+///
+/// @param id The channel id
+/// @return true if successful, false otherwise
+bool channel_close(uint64_t id, ChannelPart part, const char **error)
+{
+  Channel *chan;
+  Process *proc;
+
+  const char *dummy;
+  if (!error) {
+    error = &dummy;
+  }
+
+  if (!(chan = find_channel(id))) {
+    if (id < next_chan_id) {
+      // allow double close, even though we can't say what parts was valid.
+      return true;
+    }
+    *error = (const char *)e_invchan;
+    return false;
+  }
+
+  bool close_main = false;
+  if (part == kChannelPartRpc || part == kChannelPartAll) {
+    close_main = true;
+    if (chan->is_rpc) {
+       rpc_close(chan);
+    } else if (part == kChannelPartRpc) {
+      *error = (const char *)e_invstream;
+      return false;
+    }
+  } else if ((part == kChannelPartStdin || part == kChannelPartStdout)
+             && chan->is_rpc) {
+    *error = (const char *)e_invstreamrpc;
+    return false;
+  }
+
+  switch (chan->streamtype) {
+    case kChannelStreamSocket:
+      if (!close_main) {
+        *error = (const char *)e_invstream;
+        return false;
+      }
+      stream_may_close(&chan->stream.socket);
+      break;
+
+    case kChannelStreamProc:
+      proc = (Process *)&chan->stream.proc;
+      if (part == kChannelPartStdin || close_main) {
+        stream_may_close(&proc->in);
+      }
+      if (part == kChannelPartStdout || close_main) {
+        stream_may_close(&proc->out);
+      }
+      if (part == kChannelPartStderr || part == kChannelPartAll) {
+        stream_may_close(&proc->err);
+      }
+      if (proc->type == kProcessTypePty && part == kChannelPartAll) {
+        pty_process_close_master(&chan->stream.pty);
+      }
+
+      break;
+
+    case kChannelStreamStdio:
+      if (part == kChannelPartStdin || close_main) {
+        stream_may_close(&chan->stream.stdio.in);
+      }
+      if (part == kChannelPartStdout || close_main) {
+        stream_may_close(&chan->stream.stdio.out);
+      }
+      if (part == kChannelPartStderr) {
+        *error = (const char *)e_invstream;
+        return false;
+      }
+      break;
+
+    case kChannelStreamStderr:
+      if (part != kChannelPartAll && part != kChannelPartStderr) {
+        *error = (const char *)e_invstream;
+        return false;
+      }
+      if (!chan->stream.err.closed) {
+        chan->stream.err.closed = true;
+        // Don't close on exit, in case late error messages
+        if (!exiting) {
+          fclose(stderr);
+        }
+        channel_decref(chan);
+      }
+      break;
+
+    case kChannelStreamInternal:
+      if (!close_main) {
+        *error = (const char *)e_invstream;
+        return false;
+      }
+      break;
+  }
+
+  return true;
+}
+
+/// Initializes the module
+void channel_init(void)
+{
+  channels = pmap_new(uint64_t)();
+  channel_alloc(kChannelStreamStderr);
+  rpc_init();
+  remote_ui_init();
+}
+
+/// Allocates a channel.
+///
+/// Channel is allocated with refcount 1, which should be decreased
+/// when the underlying stream closes.
+static Channel *channel_alloc(ChannelStreamType type)
+{
+  Channel *chan = xcalloc(1, sizeof(*chan));
+  if (type == kChannelStreamStdio) {
+    chan->id = CHAN_STDIO;
+  } else if (type == kChannelStreamStderr) {
+    chan->id = CHAN_STDERR;
+  } else {
+    chan->id = next_chan_id++;
+  }
+  chan->events = multiqueue_new_child(main_loop.events);
+  chan->refcount = 1;
+  chan->streamtype = type;
+  pmap_put(uint64_t)(channels, chan->id, chan);
+  return chan;
+}
+
+/// Not implemented, only logging for now
+void channel_create_event(Channel *chan, char *ext_source)
+{
+#if MIN_LOG_LEVEL <= INFO_LOG_LEVEL
+  char *stream_desc, *mode_desc, *source;
+
+  switch (chan->streamtype) {
+    case kChannelStreamProc:
+      if (chan->stream.proc.type == kProcessTypePty) {
+          stream_desc = "pty job";
+      } else {
+          stream_desc = "job";
+      }
+      break;
+
+    case kChannelStreamStdio:
+       stream_desc = "stdio";
+       break;
+
+    case kChannelStreamSocket:
+      stream_desc = "socket";
+      break;
+
+    case kChannelStreamInternal:
+      stream_desc = "socket (internal)";
+      break;
+
+    default:
+      stream_desc = "?";
+  }
+
+  if (chan->is_rpc) {
+    mode_desc = ", rpc";
+  } else if (chan->term) {
+    mode_desc = ", terminal";
+  } else {
+    mode_desc = "";
+  }
+
+  if (ext_source) {
+    // TODO(bfredl): in a future improved traceback solution,
+    // external events should be included.
+    source = ext_source;
+  } else {
+    eval_format_source_name_line((char *)IObuff, sizeof(IObuff));
+    source = (char *)IObuff;
+  }
+
+  ILOG("new channel %" PRIu64 " (%s%s): %s", chan->id, stream_desc,
+       mode_desc, source);
+#else
+  (void)chan;
+  (void)ext_source;
+#endif
+}
+
+void channel_incref(Channel *channel)
+{
+  channel->refcount++;
+}
+
+void channel_decref(Channel *channel)
+{
+  if (!(--channel->refcount)) {
+    multiqueue_put(main_loop.fast_events, free_channel_event, 1, channel);
+  }
+}
+
+void callback_reader_free(CallbackReader *reader)
+{
+  callback_free(&reader->cb);
+  if (reader->buffered) {
+    ga_clear(&reader->buffer);
+  }
+}
+
+void callback_reader_start(CallbackReader *reader)
+{
+  if (reader->buffered) {
+    ga_init(&reader->buffer, sizeof(char *), 32);
+    ga_grow(&reader->buffer, 32);
+  }
+}
+
+static void free_channel_event(void **argv)
+{
+  Channel *channel = argv[0];
+  if (channel->is_rpc) {
+    rpc_free(channel);
+  }
+
+  callback_reader_free(&channel->on_stdout);
+  callback_reader_free(&channel->on_stderr);
+  callback_free(&channel->on_exit);
+
+  pmap_del(uint64_t)(channels, channel->id);
+  multiqueue_free(channel->events);
+  xfree(channel);
+}
+
+static void channel_destroy_early(Channel *chan)
+{
+  if ((chan->id != --next_chan_id)) {
+    abort();
+  }
+
+  if ((--chan->refcount != 0)) {
+    abort();
+  }
+
+  free_channel_event((void **)&chan);
+}
+
+
+static void close_cb(Stream *stream, void *data)
+{
+  channel_decref(data);
+}
+
+Channel *channel_job_start(char **argv, CallbackReader on_stdout,
+                           CallbackReader on_stderr, Callback on_exit,
+                           bool pty, bool rpc, bool detach, const char *cwd,
+                           uint16_t pty_width, uint16_t pty_height,
+                           char *term_name, varnumber_T *status_out)
+{
+  Channel *chan = channel_alloc(kChannelStreamProc);
+  chan->on_stdout = on_stdout;
+  chan->on_stderr = on_stderr;
+  chan->on_exit = on_exit;
+  chan->is_rpc = rpc;
+
+  if (pty) {
+    if (detach) {
+      EMSG2(_(e_invarg2), "terminal/pty job cannot be detached");
+      shell_free_argv(argv);
+      xfree(term_name);
+      channel_destroy_early(chan);
+      *status_out = 0;
+      return NULL;
+    }
+    chan->stream.pty = pty_process_init(&main_loop, chan);
+    if (pty_width > 0) {
+      chan->stream.pty.width = pty_width;
+    }
+    if (pty_height > 0) {
+      chan->stream.pty.height = pty_height;
+    }
+    if (term_name) {
+      chan->stream.pty.term_name = term_name;
+    }
+  } else {
+    chan->stream.uv = libuv_process_init(&main_loop, chan);
+  }
+
+  Process *proc = (Process *)&chan->stream.proc;
+  proc->argv = argv;
+  proc->cb = channel_process_exit_cb;
+  proc->events = chan->events;
+  proc->detach = detach;
+  proc->cwd = cwd;
+
+  char *cmd = xstrdup(proc->argv[0]);
+  bool has_out, has_err;
+  if (proc->type == kProcessTypePty) {
+    has_out = true;
+    has_err = false;
+  } else {
+    has_out = chan->is_rpc || callback_reader_set(chan->on_stdout);
+    has_err = callback_reader_set(chan->on_stderr);
+  }
+  int status = process_spawn(proc, true, has_out, has_err);
+  if (status) {
+    EMSG3(_(e_jobspawn), os_strerror(status), cmd);
+    xfree(cmd);
+    if (proc->type == kProcessTypePty) {
+      xfree(chan->stream.pty.term_name);
+    }
+    channel_destroy_early(chan);
+    *status_out = proc->status;
+    return NULL;
+  }
+  xfree(cmd);
+
+  wstream_init(&proc->in, 0);
+  if (has_out) {
+    rstream_init(&proc->out, 0);
+  }
+
+  if (chan->is_rpc) {
+    // the rpc takes over the in and out streams
+    rpc_start(chan);
+  } else {
+    if (has_out) {
+      callback_reader_start(&chan->on_stdout);
+      rstream_start(&proc->out, on_job_stdout, chan);
+    }
+  }
+
+  if (has_err) {
+    callback_reader_start(&chan->on_stderr);
+    rstream_init(&proc->err, 0);
+    rstream_start(&proc->err, on_job_stderr, chan);
+  }
+
+  *status_out = (varnumber_T)chan->id;
+  return chan;
+}
+
+
+uint64_t channel_connect(bool tcp, const char *address,
+                         bool rpc, CallbackReader on_output,
+                         int timeout, const char **error)
+{
+  if (!tcp && rpc) {
+    char *path = fix_fname(address);
+    if (server_owns_pipe_address(path)) {
+      // avoid deadlock
+      xfree(path);
+      return channel_create_internal_rpc();
+    }
+    xfree(path);
+  }
+
+  Channel *channel = channel_alloc(kChannelStreamSocket);
+  if (!socket_connect(&main_loop, &channel->stream.socket,
+                      tcp, address, timeout, error)) {
+    channel_destroy_early(channel);
+    return 0;
+  }
+
+  channel->stream.socket.internal_close_cb = close_cb;
+  channel->stream.socket.internal_data = channel;
+  wstream_init(&channel->stream.socket, 0);
+  rstream_init(&channel->stream.socket, 0);
+
+  if (rpc) {
+    rpc_start(channel);
+  } else {
+    channel->on_stdout = on_output;
+    callback_reader_start(&channel->on_stdout);
+    rstream_start(&channel->stream.socket, on_socket_output, channel);
+  }
+
+  channel_create_event(channel, NULL);
+  return channel->id;
+}
+
+/// Creates an RPC channel from a tcp/pipe socket connection
+///
+/// @param watcher The SocketWatcher ready to accept the connection
+void channel_from_connection(SocketWatcher *watcher)
+{
+  Channel *channel = channel_alloc(kChannelStreamSocket);
+  socket_watcher_accept(watcher, &channel->stream.socket);
+  channel->stream.socket.internal_close_cb = close_cb;
+  channel->stream.socket.internal_data = channel;
+  wstream_init(&channel->stream.socket, 0);
+  rstream_init(&channel->stream.socket, 0);
+  rpc_start(channel);
+  channel_create_event(channel, watcher->addr);
+}
+
+/// Creates a loopback channel. This is used to avoid deadlock
+/// when an instance connects to its own named pipe.
+static uint64_t channel_create_internal_rpc(void)
+{
+  Channel *channel = channel_alloc(kChannelStreamInternal);
+  rpc_start(channel);
+  return channel->id;
+}
+
+/// Creates an API channel from stdin/stdout. This is used when embedding
+/// Neovim
+uint64_t channel_from_stdio(bool rpc, CallbackReader on_output,
+                            const char **error)
+  FUNC_ATTR_NONNULL_ALL
+{
+  if (!headless_mode) {
+    *error = _("can only be opened in headless mode");
+    return 0;
+  }
+
+  if (did_stdio) {
+    *error = _("channel was already open");
+    return 0;
+  }
+  did_stdio = true;
+
+  Channel *channel = channel_alloc(kChannelStreamStdio);
+
+  rstream_init_fd(&main_loop, &channel->stream.stdio.in, 0, 0);
+  wstream_init_fd(&main_loop, &channel->stream.stdio.out, 1, 0);
+
+  if (rpc) {
+    rpc_start(channel);
+  } else {
+    channel->on_stdout = on_output;
+    callback_reader_start(&channel->on_stdout);
+    rstream_start(&channel->stream.stdio.in, on_stdio_input, channel);
+  }
+
+  return channel->id;
+}
+
+/// @param data will be consumed
+size_t channel_send(uint64_t id, char *data, size_t len, const char **error)
+{
+  Channel *chan = find_channel(id);
+  if (!chan) {
+    EMSG(_(e_invchan));
+    goto err;
+  }
+
+  if (chan->streamtype == kChannelStreamStderr) {
+    if (chan->stream.err.closed) {
+      *error = _("Can't send data to closed stream");
+      goto err;
+    }
+    // unbuffered write
+    size_t written = fwrite(data, len, 1, stderr);
+    xfree(data);
+    return len * written;
+  }
+
+
+  Stream *in = channel_instream(chan);
+  if (in->closed) {
+    *error = _("Can't send data to closed stream");
+    goto err;
+  }
+
+  if (chan->is_rpc) {
+    *error = _("Can't send raw data to rpc channel");
+    goto err;
+  }
+
+  WBuffer *buf = wstream_new_buffer(data, len, 1, xfree);
+  return wstream_write(in, buf) ? len : 0;
+
+err:
+  xfree(data);
+  return 0;
+}
+
+/// NB: mutates buf in place!
+static list_T *buffer_to_tv_list(char *buf, size_t count)
+{
+  list_T *ret = tv_list_alloc();
+  char *ptr = buf;
+  size_t remaining = count;
+  size_t off = 0;
+
+  while (off < remaining) {
+    // append the line
+    if (ptr[off] == NL) {
+      tv_list_append_string(ret, ptr, (ssize_t)off);
+      size_t skip = off + 1;
+      ptr += skip;
+      remaining -= skip;
+      off = 0;
+      continue;
+    }
+    if (ptr[off] == NUL) {
+      // Translate NUL to NL
+      ptr[off] = NL;
+    }
+    off++;
+  }
+  tv_list_append_string(ret, ptr, (ssize_t)off);
+  return ret;
+}
+
+// vimscript job callbacks must be executed on Nvim main loop
+static inline void process_channel_event(Channel *chan, Callback *callback,
+                                         const char *type, char *buf,
+                                         size_t count, int status)
+{
+  assert(callback);
+  ChannelEvent *event_data = xmalloc(sizeof(*event_data));
+  event_data->received = NULL;
+  if (buf) {
+    event_data->received = buffer_to_tv_list(buf, count);
+  } else {
+    event_data->status = status;
+  }
+  channel_incref(chan);  // Hold on ref to callback
+  event_data->chan = chan;
+  event_data->callback = callback;
+  event_data->type = type;
+
+  multiqueue_put(chan->events, on_channel_event, 1, event_data);
+}
+
+void on_job_stdout(Stream *stream, RBuffer *buf, size_t count,
+                   void *data, bool eof)
+{
+  Channel *chan = data;
+  on_channel_output(stream, chan, buf, count, eof, &chan->on_stdout, "stdout");
+}
+
+void on_job_stderr(Stream *stream, RBuffer *buf, size_t count,
+                   void *data, bool eof)
+{
+  Channel *chan = data;
+  on_channel_output(stream, chan, buf, count, eof, &chan->on_stderr, "stderr");
+}
+
+static void on_socket_output(Stream *stream, RBuffer *buf, size_t count,
+                             void *data, bool eof)
+{
+  Channel *chan = data;
+  on_channel_output(stream, chan, buf, count, eof, &chan->on_stdout, "data");
+}
+
+static void on_stdio_input(Stream *stream, RBuffer *buf, size_t count,
+                           void *data, bool eof)
+{
+  Channel *chan = data;
+  on_channel_output(stream, chan, buf, count, eof, &chan->on_stdout, "stdin");
+}
+
+static void on_channel_output(Stream *stream, Channel *chan, RBuffer *buf,
+                              size_t count, bool eof, CallbackReader *reader,
+                              const char *type)
+{
+  // stub variable, to keep reading consistent with the order of events, only
+  // consider the count parameter.
+  size_t r;
+  char *ptr = rbuffer_read_ptr(buf, &r);
+
+  if (eof) {
+    if (reader->buffered) {
+      if (reader->cb.type != kCallbackNone) {
+        process_channel_event(chan, &reader->cb, type, reader->buffer.ga_data,
+                              (size_t)reader->buffer.ga_len, 0);
+        ga_clear(&reader->buffer);
+      } else if (reader->self) {
+        list_T *data = buffer_to_tv_list(reader->buffer.ga_data,
+                                         (size_t)reader->buffer.ga_len);
+        tv_dict_add_list(reader->self, type, strlen(type), data);
+      } else {
+        abort();
+      }
+    } else if (reader->cb.type != kCallbackNone) {
+      process_channel_event(chan, &reader->cb, type, ptr, 0, 0);
+    }
+    return;
+  }
+
+  // The order here matters, the terminal must receive the data first because
+  // process_channel_event will modify the read buffer(convert NULs into NLs)
+  if (chan->term) {
+    terminal_receive(chan->term, ptr, count);
+  }
+
+  rbuffer_consumed(buf, count);
+  if (reader->buffered) {
+    ga_concat_len(&reader->buffer, ptr, count);
+  } else if (callback_reader_set(*reader)) {
+    process_channel_event(chan, &reader->cb, type, ptr, count, 0);
+  }
+}
+
+static void channel_process_exit_cb(Process *proc, int status, void *data)
+{
+  Channel *chan = data;
+  if (chan->term) {
+    char msg[sizeof("\r\n[Process exited ]") + NUMBUFLEN];
+    snprintf(msg, sizeof msg, "\r\n[Process exited %d]", proc->status);
+    terminal_close(chan->term, msg);
+  }
+
+  // if status is -1 the process did not really exit,
+  // we just closed the handle onto a detached process
+  if (status >= 0) {
+    process_channel_event(chan, &chan->on_exit, "exit", NULL, 0, status);
+  }
+
+  channel_decref(chan);
+}
+
+static void on_channel_event(void **args)
+{
+  ChannelEvent *ev = (ChannelEvent *)args[0];
+
+  typval_T argv[4];
+
+  argv[0].v_type = VAR_NUMBER;
+  argv[0].v_lock = VAR_UNLOCKED;
+  argv[0].vval.v_number = (varnumber_T)ev->chan->id;
+
+  if (ev->received) {
+    argv[1].v_type = VAR_LIST;
+    argv[1].v_lock = VAR_UNLOCKED;
+    argv[1].vval.v_list = ev->received;
+    argv[1].vval.v_list->lv_refcount++;
+  } else {
+    argv[1].v_type = VAR_NUMBER;
+    argv[1].v_lock = VAR_UNLOCKED;
+    argv[1].vval.v_number = ev->status;
+  }
+
+  argv[2].v_type = VAR_STRING;
+  argv[2].v_lock = VAR_UNLOCKED;
+  argv[2].vval.v_string = (uint8_t *)ev->type;
+
+  typval_T rettv = TV_INITIAL_VALUE;
+  callback_call(ev->callback, 3, argv, &rettv);
+  tv_clear(&rettv);
+  channel_decref(ev->chan);
+  xfree(ev);
+}
+
+
+/// Open terminal for channel
+///
+/// Channel `chan` is assumed to be an open pty channel,
+/// and curbuf is assumed to be a new, unmodified buffer.
+void channel_terminal_open(Channel *chan)
+{
+  TerminalOptions topts;
+  topts.data = chan;
+  topts.width = chan->stream.pty.width;
+  topts.height = chan->stream.pty.height;
+  topts.write_cb = term_write;
+  topts.resize_cb = term_resize;
+  topts.close_cb = term_close;
+  curbuf->b_p_channel = (long)chan->id;  // 'channel' option
+  Terminal *term = terminal_open(topts);
+  chan->term = term;
+  channel_incref(chan);
+}
+
+static void term_write(char *buf, size_t size, void *data)
+{
+  Channel *chan = data;
+  if (chan->stream.proc.in.closed) {
+    // If the backing stream was closed abruptly, there may be write events
+    // ahead of the terminal close event. Just ignore the writes.
+    ILOG("write failed: stream is closed");
+    return;
+  }
+  WBuffer *wbuf = wstream_new_buffer(xmemdup(buf, size), size, 1, xfree);
+  wstream_write(&chan->stream.proc.in, wbuf);
+}
+
+static void term_resize(uint16_t width, uint16_t height, void *data)
+{
+  Channel *chan = data;
+  pty_process_resize(&chan->stream.pty, width, height);
+}
+
+static inline void term_delayed_free(void **argv)
+{
+  Channel *chan = argv[0];
+  if (chan->stream.proc.in.pending_reqs || chan->stream.proc.out.pending_reqs) {
+    multiqueue_put(chan->events, term_delayed_free, 1, chan);
+    return;
+  }
+
+  terminal_destroy(chan->term);
+  chan->term = NULL;
+  channel_decref(chan);
+}
+
+static void term_close(void *data)
+{
+  Channel *chan = data;
+  process_stop(&chan->stream.proc);
+  multiqueue_put(chan->events, term_delayed_free, 1, data);
+}
+
diff --git a/src/nvim/channel.h b/src/nvim/channel.h
new file mode 100644
index 0000000000..b856d197f1
--- /dev/null
+++ b/src/nvim/channel.h
@@ -0,0 +1,134 @@
+#ifndef NVIM_CHANNEL_H
+#define NVIM_CHANNEL_H
+
+#include "nvim/main.h"
+#include "nvim/event/socket.h"
+#include "nvim/event/process.h"
+#include "nvim/os/pty_process.h"
+#include "nvim/event/libuv_process.h"
+#include "nvim/eval/typval.h"
+#include "nvim/msgpack_rpc/channel_defs.h"
+
+#define CHAN_STDIO 1
+#define CHAN_STDERR 2
+
+typedef enum {
+  kChannelStreamProc,
+  kChannelStreamSocket,
+  kChannelStreamStdio,
+  kChannelStreamStderr,
+  kChannelStreamInternal
+} ChannelStreamType;
+
+typedef enum {
+  kChannelPartStdin,
+  kChannelPartStdout,
+  kChannelPartStderr,
+  kChannelPartRpc,
+  kChannelPartAll
+} ChannelPart;
+
+
+typedef struct {
+  Stream in;
+  Stream out;
+} StdioPair;
+
+typedef struct {
+  bool closed;
+} StderrState;
+
+typedef struct {
+  Callback cb;
+  dict_T *self;
+  garray_T buffer;
+  bool buffered;
+} CallbackReader;
+
+#define CALLBACK_READER_INIT ((CallbackReader){ .cb = CALLBACK_NONE, \
+                                                .self = NULL, \
+                                                .buffer = GA_EMPTY_INIT_VALUE, \
+                                                .buffered = false })
+static inline bool callback_reader_set(CallbackReader reader)
+{
+  return reader.cb.type != kCallbackNone || reader.self;
+}
+
+struct Channel {
+  uint64_t id;
+  size_t refcount;
+  MultiQueue *events;
+
+  ChannelStreamType streamtype;
+  union {
+    Process proc;
+    LibuvProcess uv;
+    PtyProcess pty;
+    Stream socket;
+    StdioPair stdio;
+    StderrState err;
+  } stream;
+
+  bool is_rpc;
+  RpcState rpc;
+  Terminal *term;
+
+  CallbackReader on_stdout;
+  CallbackReader on_stderr;
+  Callback on_exit;
+};
+
+EXTERN PMap(uint64_t) *channels;
+
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# include "channel.h.generated.h"
+#endif
+
+/// @returns Channel with the id or NULL if not found
+static inline Channel *find_channel(uint64_t id)
+{
+  return pmap_get(uint64_t)(channels, id);
+}
+
+static inline Stream *channel_instream(Channel *chan)
+  FUNC_ATTR_NONNULL_ALL
+{
+  switch (chan->streamtype) {
+    case kChannelStreamProc:
+      return &chan->stream.proc.in;
+
+    case kChannelStreamSocket:
+      return &chan->stream.socket;
+
+    case kChannelStreamStdio:
+      return &chan->stream.stdio.out;
+
+    case kChannelStreamInternal:
+    case kChannelStreamStderr:
+      abort();
+  }
+  abort();
+}
+
+static inline Stream *channel_outstream(Channel *chan)
+  FUNC_ATTR_NONNULL_ALL
+{
+  switch (chan->streamtype) {
+    case kChannelStreamProc:
+      return &chan->stream.proc.out;
+
+    case kChannelStreamSocket:
+      return &chan->stream.socket;
+
+    case kChannelStreamStdio:
+      return &chan->stream.stdio.in;
+
+    case kChannelStreamInternal:
+    case kChannelStreamStderr:
+      abort();
+  }
+  abort();
+}
+
+
+#endif  // NVIM_CHANNEL_H
diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index f414e771d7..577aa67c60 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -24,6 +24,7 @@
 #endif
 #include "nvim/eval.h"
 #include "nvim/buffer.h"
+#include "nvim/channel.h"
 #include "nvim/charset.h"
 #include "nvim/cursor.h"
 #include "nvim/diff.h"
@@ -365,6 +366,7 @@ static struct vimvar {
   VV(VV_DYING,          "dying",            VAR_NUMBER, VV_RO),
   VV(VV_EXCEPTION,      "exception",        VAR_STRING, VV_RO),
   VV(VV_THROWPOINT,     "throwpoint",       VAR_STRING, VV_RO),
+  VV(VV_STDERR,         "stderr",           VAR_NUMBER, VV_RO),
   VV(VV_REG,            "register",         VAR_STRING, VV_RO),
   VV(VV_CMDBANG,        "cmdbang",          VAR_NUMBER, VV_RO),
   VV(VV_INSERTMODE,     "insertmode",       VAR_STRING, VV_RO),
@@ -437,31 +439,6 @@ static ScopeDictDictItem vimvars_var;
 #define vimvarht  vimvardict.dv_hashtab
 
 typedef struct {
-  union {
-    LibuvProcess uv;
-    PtyProcess pty;
-  } proc;
-  Stream in, out, err;  // Initialized in common_job_start().
-  Terminal *term;
-  bool stopped;
-  bool exited;
-  bool rpc;
-  int refcount;
-  Callback on_stdout, on_stderr, on_exit;
-  varnumber_T *status_ptr;
-  uint64_t id;
-  MultiQueue *events;
-} TerminalJobData;
-
-typedef struct {
-  TerminalJobData *data;
-  Callback *callback;
-  const char *type;
-  list_T *received;
-  int status;
-} JobEvent;
-
-typedef struct {
   TimeWatcher tw;
   int timer_id;
   int repeat_count;
@@ -513,7 +490,6 @@ typedef enum {
 #define FNE_INCL_BR     1       /* find_name_end(): include [] in name */
 #define FNE_CHECK_START 2       /* find_name_end(): check name starts with
                                    valid character */
-static PMap(uint64_t) *jobs = NULL;
 
 static uint64_t last_timer_id = 0;
 static PMap(uint64_t) *timers = NULL;
@@ -556,7 +532,6 @@ void eval_init(void)
 {
   vimvars[VV_VERSION].vv_nr = VIM_VERSION_100;
 
-  jobs = pmap_new(uint64_t)();
   timers = pmap_new(uint64_t)();
   struct vimvar   *p;
 
@@ -612,6 +587,7 @@ void eval_init(void)
   v_event->dv_lock = VAR_FIXED;
   set_vim_var_dict(VV_EVENT, v_event);
   set_vim_var_list(VV_ERRORS, tv_list_alloc());
+  set_vim_var_nr(VV_STDERR,   CHAN_STDERR);
   set_vim_var_nr(VV_SEARCHFORWARD, 1L);
   set_vim_var_nr(VV_HLSEARCH, 1L);
   set_vim_var_nr(VV_COUNT1, 1);
@@ -5139,12 +5115,12 @@ bool garbage_collect(bool testing)
   // named functions (matters for closures)
   ABORTING(set_ref_in_functions(copyID));
 
-  // Jobs
+  // Channels
   {
-    TerminalJobData *data;
-    map_foreach_value(jobs, data, {
-      set_ref_in_callback(&data->on_stdout, copyID, NULL, NULL);
-      set_ref_in_callback(&data->on_stderr, copyID, NULL, NULL);
+    Channel *data;
+    map_foreach_value(channels, data, {
+      set_ref_in_callback_reader(&data->on_stdout, copyID, NULL, NULL);
+      set_ref_in_callback_reader(&data->on_stderr, copyID, NULL, NULL);
       set_ref_in_callback(&data->on_exit, copyID, NULL, NULL);
     })
   }
@@ -7348,6 +7324,76 @@ static void f_changenr(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   rettv->vval.v_number = curbuf->b_u_seq_cur;
 }
 
+// "chanclose(id[, stream])" function
+static void f_chanclose(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+{
+  rettv->v_type = VAR_NUMBER;
+  rettv->vval.v_number = 0;
+
+  if (check_restricted() || check_secure()) {
+    return;
+  }
+
+  if (argvars[0].v_type != VAR_NUMBER || (argvars[1].v_type != VAR_STRING
+        && argvars[1].v_type != VAR_UNKNOWN)) {
+    EMSG(_(e_invarg));
+    return;
+  }
+
+  ChannelPart part = kChannelPartAll;
+  if (argvars[1].v_type == VAR_STRING) {
+    char *stream = (char *)argvars[1].vval.v_string;
+    if (!strcmp(stream, "stdin")) {
+      part = kChannelPartStdin;
+    } else if (!strcmp(stream, "stdout")) {
+      part = kChannelPartStdout;
+    } else if (!strcmp(stream, "stderr")) {
+      part = kChannelPartStderr;
+    } else if (!strcmp(stream, "rpc")) {
+      part = kChannelPartRpc;
+    } else {
+      EMSG2(_("Invalid channel stream \"%s\""), stream);
+      return;
+    }
+  }
+  const char *error;
+  rettv->vval.v_number = channel_close(argvars[0].vval.v_number, part, &error);
+  if (!rettv->vval.v_number) {
+    EMSG(error);
+  }
+}
+
+// "chansend(id, data)" function
+static void f_chansend(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+{
+  rettv->v_type = VAR_NUMBER;
+  rettv->vval.v_number = 0;
+
+  if (check_restricted() || check_secure()) {
+    return;
+  }
+
+  if (argvars[0].v_type != VAR_NUMBER || argvars[1].v_type == VAR_UNKNOWN) {
+    // First argument is the channel id and second is the data to write
+    EMSG(_(e_invarg));
+    return;
+  }
+
+  ptrdiff_t input_len = 0;
+  char *input = save_tv_as_string(&argvars[1], &input_len, false);
+  if (!input) {
+    // Either the error has been handled by save_tv_as_string(),
+    // or there is no input to send.
+    return;
+  }
+  uint64_t id = argvars[0].vval.v_number;
+  const char *error = NULL;
+  rettv->vval.v_number = channel_send(id, input, input_len, &error);
+  if (error) {
+    EMSG(error);
+  }
+}
+
 /*
  * "char2nr(string)" function
  */
@@ -11417,68 +11463,6 @@ static void f_items(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   dict_list(argvars, rettv, 2);
 }
 
-// "jobclose(id[, stream])" function
-static void f_jobclose(typval_T *argvars, typval_T *rettv, FunPtr fptr)
-{
-  rettv->v_type = VAR_NUMBER;
-  rettv->vval.v_number = 0;
-
-  if (check_restricted() || check_secure()) {
-    return;
-  }
-
-  if (argvars[0].v_type != VAR_NUMBER || (argvars[1].v_type != VAR_STRING
-        && argvars[1].v_type != VAR_UNKNOWN)) {
-    EMSG(_(e_invarg));
-    return;
-  }
-
-  TerminalJobData *data = find_job(argvars[0].vval.v_number);
-  if (!data) {
-    EMSG(_(e_invjob));
-    return;
-  }
-
-  Process *proc = (Process *)&data->proc;
-
-  if (argvars[1].v_type == VAR_STRING) {
-    char *stream = (char *)argvars[1].vval.v_string;
-    if (!strcmp(stream, "stdin")) {
-      if (data->rpc) {
-        EMSG(_("Invalid stream on rpc job, use jobclose(id, 'rpc')"));
-      } else {
-        process_close_in(proc);
-      }
-    } else if (!strcmp(stream, "stdout")) {
-      if (data->rpc) {
-        EMSG(_("Invalid stream on rpc job, use jobclose(id, 'rpc')"));
-      } else {
-        process_close_out(proc);
-      }
-    } else if (!strcmp(stream, "stderr")) {
-      process_close_err(proc);
-    } else if (!strcmp(stream, "rpc")) {
-      if (data->rpc) {
-        channel_close(data->id);
-      } else {
-        EMSG(_("Invalid job stream: Not an rpc job"));
-      }
-    } else {
-      EMSG2(_("Invalid job stream \"%s\""), stream);
-    }
-  } else {
-    if (data->rpc) {
-      channel_close(data->id);
-      process_close_err(proc);
-    } else {
-      process_close_streams(proc);
-      if (proc->type == kProcessTypePty) {
-        pty_process_close_master(&data->proc.pty);
-      }
-    }
-  }
-}
-
 // "jobpid(id)" function
 static void f_jobpid(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 {
@@ -11494,61 +11478,15 @@ static void f_jobpid(typval_T *argvars, typval_T *rettv, FunPtr fptr)
     return;
   }
 
-  TerminalJobData *data = find_job(argvars[0].vval.v_number);
+  Channel *data = find_job(argvars[0].vval.v_number, true);
   if (!data) {
-    EMSG(_(e_invjob));
     return;
   }
 
-  Process *proc = (Process *)&data->proc;
+  Process *proc = (Process *)&data->stream.proc;
   rettv->vval.v_number = proc->pid;
 }
 
-// "jobsend()" function
-static void f_jobsend(typval_T *argvars, typval_T *rettv, FunPtr fptr)
-{
-  rettv->v_type = VAR_NUMBER;
-  rettv->vval.v_number = 0;
-
-  if (check_restricted() || check_secure()) {
-    return;
-  }
-
-  if (argvars[0].v_type != VAR_NUMBER || argvars[1].v_type == VAR_UNKNOWN) {
-    // First argument is the job id and second is the string or list to write
-    // to the job's stdin
-    EMSG(_(e_invarg));
-    return;
-  }
-
-  TerminalJobData *data = find_job(argvars[0].vval.v_number);
-  if (!data) {
-    EMSG(_(e_invjob));
-    return;
-  }
-
-  if (((Process *)&data->proc)->in->closed) {
-    EMSG(_("Can't send data to the job: stdin is closed"));
-    return;
-  }
-
-  if (data->rpc) {
-    EMSG(_("Can't send raw data to rpc channel"));
-    return;
-  }
-
-  ptrdiff_t input_len = 0;
-  char *input = save_tv_as_string(&argvars[1], &input_len, false);
-  if (!input) {
-    // Either the error has been handled by save_tv_as_string(), or there is no
-    // input to send.
-    return;
-  }
-
-  WBuffer *buf = wstream_new_buffer(input, input_len, 1, xfree);
-  rettv->vval.v_number = wstream_write(data->proc.uv.process.in, buf);
-}
-
 // "jobresize(job, width, height)" function
 static void f_jobresize(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 {
@@ -11567,19 +11505,18 @@ static void f_jobresize(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   }
 
 
-  TerminalJobData *data = find_job(argvars[0].vval.v_number);
+  Channel *data = find_job(argvars[0].vval.v_number, true);
   if (!data) {
-    EMSG(_(e_invjob));
     return;
   }
 
-  if (data->proc.uv.process.type != kProcessTypePty) {
-    EMSG(_(e_jobnotpty));
+  if (data->stream.proc.type != kProcessTypePty) {
+    EMSG(_(e_channotpty));
     return;
   }
 
-  pty_process_resize(&data->proc.pty, argvars[1].vval.v_number,
-      argvars[2].vval.v_number);
+  pty_process_resize(&data->stream.pty, argvars[1].vval.v_number,
+                     argvars[2].vval.v_number);
   rettv->vval.v_number = 1;
 }
 
@@ -11664,8 +11601,8 @@ static void f_jobstart(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   bool detach = false;
   bool rpc = false;
   bool pty = false;
-  Callback on_stdout = CALLBACK_NONE;
-  Callback on_stderr = CALLBACK_NONE;
+  CallbackReader on_stdout = CALLBACK_READER_INIT,
+                 on_stderr = CALLBACK_READER_INIT;
   Callback on_exit = CALLBACK_NONE;
   char *cwd = NULL;
   if (argvars[1].v_type == VAR_DICT) {
@@ -11697,32 +11634,21 @@ static void f_jobstart(typval_T *argvars, typval_T *rettv, FunPtr fptr)
     }
   }
 
-  TerminalJobData *data = common_job_init(argv, on_stdout, on_stderr, on_exit,
-                                          pty, rpc, detach, cwd);
-  Process *proc = (Process *)&data->proc;
+  uint16_t width = 0, height = 0;
+  char *term_name = NULL;
 
   if (pty) {
-    uint16_t width = (uint16_t)tv_dict_get_number(job_opts, "width");
-    if (width > 0) {
-      data->proc.pty.width = width;
-    }
-    uint16_t height = (uint16_t)tv_dict_get_number(job_opts, "height");
-    if (height > 0) {
-      data->proc.pty.height = height;
-    }
-    char *term = tv_dict_get_string(job_opts, "TERM", true);
-    if (term) {
-      data->proc.pty.term_name = term;
-    }
+    width = (uint16_t)tv_dict_get_number(job_opts, "width");
+    height = (uint16_t)tv_dict_get_number(job_opts, "height");
+    term_name = tv_dict_get_string(job_opts, "TERM", true);
   }
 
-  if (!rpc && on_stdout.type == kCallbackNone) {
-    proc->out = NULL;
+  Channel *chan = channel_job_start(argv, on_stdout, on_stderr, on_exit, pty,
+                                    rpc, detach, cwd, width, height, term_name,
+                                    &rettv->vval.v_number);
+  if (chan) {
+    channel_create_event(chan, NULL);
   }
-  if (on_stderr.type == kCallbackNone) {
-    proc->err = NULL;
-  }
-  common_job_start(data, rettv);
 }
 
 // "jobstop()" function
@@ -11742,14 +11668,12 @@ static void f_jobstop(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   }
 
 
-  TerminalJobData *data = find_job(argvars[0].vval.v_number);
+  Channel *data = find_job(argvars[0].vval.v_number, true);
   if (!data) {
-    EMSG(_(e_invjob));
     return;
   }
 
-  process_stop((Process *)&data->proc);
-  data->stopped = true;
+  process_stop((Process *)&data->stream.proc);
   rettv->vval.v_number = 1;
 }
 
@@ -11769,28 +11693,31 @@ static void f_jobwait(typval_T *argvars, typval_T *rettv, FunPtr fptr)
     return;
   }
 
+
   list_T *args = argvars[0].vval.v_list;
-  list_T *rv = tv_list_alloc();
+  Channel **jobs = xcalloc(args->lv_len, sizeof(*jobs));
 
   ui_busy_start();
   MultiQueue *waiting_jobs = multiqueue_new_parent(loop_on_put, &main_loop);
   // For each item in the input list append an integer to the output list. -3
   // is used to represent an invalid job id, -2 is for a interrupted job and
   // -1 for jobs that were skipped or timed out.
-  for (listitem_T *arg = args->lv_first; arg != NULL; arg = arg->li_next) {
-    TerminalJobData *data = NULL;
+
+  int i = 0;
+  for (listitem_T *arg = args->lv_first; arg != NULL; arg = arg->li_next, i++) {
+    Channel *chan = NULL;
     if (arg->li_tv.v_type != VAR_NUMBER
-        || !(data = find_job(arg->li_tv.vval.v_number))) {
-      tv_list_append_number(rv, -3);
+        || !(chan = find_job(arg->li_tv.vval.v_number, false))) {
+      jobs[i] = NULL;
     } else {
-      // append the list item and set the status pointer so we'll collect the
-      // status code when the job exits
-      tv_list_append_number(rv, -1);
-      data->status_ptr = &rv->lv_last->li_tv.vval.v_number;
-      // Process any pending events for the job because we'll temporarily
-      // replace the parent queue
-      multiqueue_process_events(data->events);
-      multiqueue_replace_parent(data->events, waiting_jobs);
+      jobs[i] = chan;
+      channel_incref(chan);
+      if (chan->stream.proc.status < 0) {
+        // Process any pending events for the job because we'll temporarily
+        // replace the parent queue
+        multiqueue_process_events(chan->events);
+        multiqueue_replace_parent(chan->events, waiting_jobs);
+      }
     }
   }
 
@@ -11801,24 +11728,21 @@ static void f_jobwait(typval_T *argvars, typval_T *rettv, FunPtr fptr)
     before = os_hrtime();
   }
 
-  for (listitem_T *arg = args->lv_first; arg != NULL; arg = arg->li_next) {
-    TerminalJobData *data = NULL;
+  for (i = 0; i < args->lv_len; i++) {
     if (remaining == 0) {
       // timed out
       break;
     }
-    if (arg->li_tv.v_type != VAR_NUMBER
-        || !(data = find_job(arg->li_tv.vval.v_number))) {
+
+    // if the job already exited, but wasn't freed yet
+    if (jobs[i] == NULL || jobs[i]->stream.proc.status >= 0) {
       continue;
     }
-    int status = process_wait((Process *)&data->proc, remaining, waiting_jobs);
+
+    int status = process_wait(&jobs[i]->stream.proc, remaining,
+                              waiting_jobs);
     if (status < 0) {
       // interrupted or timed out, skip remaining jobs.
-      if (status == -2) {
-        // set the status so the user can distinguish between interrupted and
-        // skipped/timeout jobs.
-        *data->status_ptr = -2;
-      }
       break;
     }
     if (remaining > 0) {
@@ -11831,30 +11755,24 @@ static void f_jobwait(typval_T *argvars, typval_T *rettv, FunPtr fptr)
     }
   }
 
-  for (listitem_T *arg = args->lv_first; arg != NULL; arg = arg->li_next) {
-    TerminalJobData *data = NULL;
-    if (arg->li_tv.v_type != VAR_NUMBER
-        || !(data = find_job(arg->li_tv.vval.v_number))) {
-      continue;
-    }
-    // remove the status pointer because the list may be freed before the
-    // job exits
-    data->status_ptr = NULL;
-  }
+  list_T *rv = tv_list_alloc();
 
   // restore the parent queue for any jobs still alive
-  for (listitem_T *arg = args->lv_first; arg != NULL; arg = arg->li_next) {
-    TerminalJobData *data = NULL;
-    if (arg->li_tv.v_type != VAR_NUMBER
-        || !(data = pmap_get(uint64_t)(jobs, arg->li_tv.vval.v_number))) {
+  for (i = 0; i < args->lv_len; i++) {
+    if (jobs[i] == NULL) {
+      tv_list_append_number(rv, -3);
       continue;
     }
     // restore the parent queue for the job
-    multiqueue_process_events(data->events);
-    multiqueue_replace_parent(data->events, main_loop.events);
+    multiqueue_process_events(jobs[i]->events);
+    multiqueue_replace_parent(jobs[i]->events, main_loop.events);
+
+    tv_list_append_number(rv, jobs[i]->stream.proc.status);
+    channel_decref(jobs[i]);
   }
 
   multiqueue_free(waiting_jobs);
+  xfree(jobs);
   ui_busy_stop();
   rv->lv_refcount++;
   rettv->v_type = VAR_LIST;
@@ -13803,9 +13721,8 @@ static void f_rpcnotify(typval_T *argvars, typval_T *rettv, FunPtr fptr)
     ADD(args, vim_to_object(tv));
   }
 
-  if (!channel_send_event((uint64_t)argvars[0].vval.v_number,
-                          tv_get_string(&argvars[1]),
-                          args)) {
+  if (!rpc_send_event((uint64_t)argvars[0].vval.v_number,
+                      tv_get_string(&argvars[1]), args)) {
     EMSG2(_(e_invarg2), "Channel doesn't exist");
     return;
   }
@@ -13870,10 +13787,8 @@ static void f_rpcrequest(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 
 
   Error err = ERROR_INIT;
-  Object result = channel_send_call((uint64_t)argvars[0].vval.v_number,
-                                    tv_get_string(&argvars[1]),
-                                    args,
-                                    &err);
+  Object result = rpc_send_call((uint64_t)argvars[0].vval.v_number,
+                                tv_get_string(&argvars[1]), args, &err);
 
   if (l_provider_call_nesting) {
     current_SID = save_current_SID;
@@ -13954,10 +13869,13 @@ static void f_rpcstart(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   // The last item of argv must be NULL
   argv[i] = NULL;
 
-  TerminalJobData *data = common_job_init(argv, CALLBACK_NONE, CALLBACK_NONE,
-                                          CALLBACK_NONE, false, true, false,
-                                          NULL);
-  common_job_start(data, rettv);
+  Channel *chan = channel_job_start(argv, CALLBACK_READER_INIT,
+                                    CALLBACK_READER_INIT, CALLBACK_NONE,
+                                    false, true, false, NULL, 0, 0, NULL,
+                                    &rettv->vval.v_number);
+  if (chan) {
+    channel_create_event(chan, NULL);
+  }
 }
 
 // "rpcstop()" function
@@ -13977,10 +13895,16 @@ static void f_rpcstop(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   }
 
   // if called with a job, stop it, else closes the channel
-  if (pmap_get(uint64_t)(jobs, argvars[0].vval.v_number)) {
+  uint64_t id = argvars[0].vval.v_number;
+  if (find_job(id, false)) {
     f_jobstop(argvars, rettv, NULL);
   } else {
-    rettv->vval.v_number = channel_close(argvars[0].vval.v_number);
+    const char *error;
+    rettv->vval.v_number = channel_close(argvars[0].vval.v_number,
+                                         kChannelPartRpc, &error);
+    if (!rettv->vval.v_number) {
+      EMSG(error);
+    }
   }
 }
 
@@ -15157,19 +15081,22 @@ static void f_sockconnect(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   }
 
   bool rpc = false;
+  CallbackReader on_data = CALLBACK_READER_INIT;
   if (argvars[2].v_type == VAR_DICT) {
     dict_T *opts = argvars[2].vval.v_dict;
     rpc = tv_dict_get_number(opts, "rpc") != 0;
-  }
 
-  if (!rpc) {
-    EMSG2(_(e_invarg2), "rpc option must be true");
-    return;
+    if (!tv_dict_get_callback(opts, S_LEN("on_data"), &on_data.cb)) {
+      return;
+    }
+    on_data.buffered = tv_dict_get_number(opts, "data_buffered");
+    if (on_data.buffered && on_data.cb.type == kCallbackNone) {
+      on_data.self = opts;
+    }
   }
 
   const char *error = NULL;
-  eval_format_source_name_line((char *)IObuff, sizeof(IObuff));
-  uint64_t id = channel_connect(tcp, address, 50, (char *)IObuff, &error);
+  uint64_t id = channel_connect(tcp, address, rpc, on_data, 50, &error);
 
   if (error) {
     EMSG2(_("connection failed: %s"), error);
@@ -15549,6 +15476,39 @@ static void f_sort(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   do_sort_uniq(argvars, rettv, true);
 }
 
+/// "stdioopen()" function
+static void f_stdioopen(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+{
+  if (argvars[0].v_type != VAR_DICT) {
+    EMSG(_(e_invarg));
+    return;
+  }
+
+
+  bool rpc = false;
+  CallbackReader on_stdin = CALLBACK_READER_INIT;
+  dict_T *opts = argvars[0].vval.v_dict;
+  rpc = tv_dict_get_number(opts, "rpc") != 0;
+
+  if (!tv_dict_get_callback(opts, S_LEN("on_stdin"), &on_stdin.cb)) {
+    return;
+  }
+  on_stdin.buffered = tv_dict_get_number(opts, "stdin_buffered");
+  if (on_stdin.buffered && on_stdin.cb.type == kCallbackNone) {
+    on_stdin.self = opts;
+  }
+
+  const char *error;
+  uint64_t id = channel_from_stdio(rpc, on_stdin, &error);
+  if (!id) {
+    EMSG2(e_stdiochan2, error);
+  }
+
+
+  rettv->vval.v_number = (varnumber_T)id;
+  rettv->v_type = VAR_NUMBER;
+}
+
 /// "uniq({list})" function
 static void f_uniq(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 {
@@ -16665,8 +16625,9 @@ static void f_termopen(typval_T *argvars, typval_T *rettv, FunPtr fptr)
     return;
   }
 
-  Callback on_stdout = CALLBACK_NONE, on_stderr = CALLBACK_NONE,
-           on_exit = CALLBACK_NONE;
+  CallbackReader on_stdout = CALLBACK_READER_INIT,
+                 on_stderr = CALLBACK_READER_INIT;
+  Callback on_exit = CALLBACK_NONE;
   dict_T *job_opts = NULL;
   const char *cwd = ".";
   if (argvars[1].v_type == VAR_DICT) {
@@ -16690,23 +16651,16 @@ static void f_termopen(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   }
 
   uint16_t term_width = MAX(0, curwin->w_width - win_col_off(curwin));
-  TerminalJobData *data = common_job_init(argv, on_stdout, on_stderr, on_exit,
-                                          true, false, false, cwd);
-  data->proc.pty.width = term_width;
-  data->proc.pty.height = curwin->w_height;
-  data->proc.pty.term_name = xstrdup("xterm-256color");
-  if (!common_job_start(data, rettv)) {
+  Channel *chan = channel_job_start(argv, on_stdout, on_stderr, on_exit,
+                                    true, false, false, cwd,
+                                    term_width, curwin->w_height,
+                                    xstrdup("xterm-256color"),
+                                    &rettv->vval.v_number);
+  if (rettv->vval.v_number <= 0) {
     return;
   }
-  TerminalOptions topts;
-  topts.data = data;
-  topts.width = term_width;
-  topts.height = curwin->w_height;
-  topts.write_cb = term_write;
-  topts.resize_cb = term_resize;
-  topts.close_cb = term_close;
 
-  int pid = data->proc.pty.process.pid;
+  int pid = chan->stream.pty.process.pid;
 
   char buf[1024];
   // format the title with the pid to conform with the term:// URI
@@ -16717,18 +16671,16 @@ static void f_termopen(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   (void)setfname(curbuf, (char_u *)buf, NULL, true);
   // Save the job id and pid in b:terminal_job_{id,pid}
   Error err = ERROR_INIT;
+  // deprecated: use 'channel' buffer option
   dict_set_var(curbuf->b_vars, cstr_as_string("terminal_job_id"),
-               INTEGER_OBJ(rettv->vval.v_number), false, false, &err);
+               INTEGER_OBJ(chan->id), false, false, &err);
   api_clear_error(&err);
   dict_set_var(curbuf->b_vars, cstr_as_string("terminal_job_pid"),
                INTEGER_OBJ(pid), false, false, &err);
   api_clear_error(&err);
 
-  Terminal *term = terminal_open(topts);
-  data->term = term;
-  data->refcount++;
-
-  return;
+  channel_terminal_open(chan);
+  channel_create_event(chan, NULL);
 }
 
 // "test_garbagecollect_now()" function
@@ -16761,30 +16713,6 @@ bool callback_from_typval(Callback *const callback, typval_T *const arg)
   return true;
 }
 
-/// Unref/free callback
-void callback_free(Callback *const callback)
-  FUNC_ATTR_NONNULL_ALL
-{
-  switch (callback->type) {
-    case kCallbackFuncref: {
-      func_unref(callback->data.funcref);
-      xfree(callback->data.funcref);
-      break;
-    }
-    case kCallbackPartial: {
-      partial_unref(callback->data.partial);
-      break;
-    }
-    case kCallbackNone: {
-      break;
-    }
-    default: {
-      abort();
-    }
-  }
-  callback->type = kCallbackNone;
-}
-
 bool callback_call(Callback *const callback, const int argcount_in,
                    typval_T *const argvars_in, typval_T *const rettv)
   FUNC_ATTR_NONNULL_ALL
@@ -16839,6 +16767,23 @@ static bool set_ref_in_callback(Callback *callback, int copyID,
   return false;
 }
 
+static bool set_ref_in_callback_reader(CallbackReader *reader, int copyID,
+                                       ht_stack_T **ht_stack,
+                                       list_stack_T **list_stack)
+{
+  if (set_ref_in_callback(&reader->cb, copyID, ht_stack, list_stack)) {
+    return true;
+  }
+
+  if (reader->self) {
+    typval_T tv;
+    tv.v_type = VAR_DICT;
+    tv.vval.v_dict = reader->self;
+    return set_ref_in_item(&tv, copyID, ht_stack, list_stack);
+  }
+  return false;
+}
+
 static void add_timer_info(typval_T *rettv, timer_T *timer)
 {
   list_T *list = rettv->vval.v_list;
@@ -22403,318 +22348,54 @@ char_u *do_string_sub(char_u *str, char_u *pat, char_u *sub,
   return ret;
 }
 
-static inline TerminalJobData *common_job_init(char **argv,
-                                               Callback on_stdout,
-                                               Callback on_stderr,
-                                               Callback on_exit,
-                                               bool pty,
-                                               bool rpc,
-                                               bool detach,
-                                               const char *cwd)
-{
-  TerminalJobData *data = xcalloc(1, sizeof(TerminalJobData));
-  data->stopped = false;
-  data->on_stdout = on_stdout;
-  data->on_stderr = on_stderr;
-  data->on_exit = on_exit;
-  data->events = multiqueue_new_child(main_loop.events);
-  data->rpc = rpc;
-  if (pty) {
-    data->proc.pty = pty_process_init(&main_loop, data);
-  } else {
-    data->proc.uv = libuv_process_init(&main_loop, data);
-  }
-  Process *proc = (Process *)&data->proc;
-  proc->argv = argv;
-  proc->in = &data->in;
-  proc->out = &data->out;
-  if (!pty) {
-    proc->err = &data->err;
-  }
-  proc->cb = eval_job_process_exit_cb;
-  proc->events = data->events;
-  proc->detach = detach;
-  proc->cwd = cwd;
-  return data;
-}
-
 /// common code for getting job callbacks for jobstart, termopen and rpcstart
 ///
 /// @return true/false on success/failure.
-static inline bool common_job_callbacks(dict_T *vopts, Callback *on_stdout,
-                                        Callback *on_stderr, Callback *on_exit)
+static inline bool common_job_callbacks(dict_T *vopts,
+                                        CallbackReader *on_stdout,
+                                        CallbackReader *on_stderr,
+                                        Callback *on_exit)
 {
-  if (tv_dict_get_callback(vopts, S_LEN("on_stdout"), on_stdout)
-      &&tv_dict_get_callback(vopts, S_LEN("on_stderr"), on_stderr)
+  if (tv_dict_get_callback(vopts, S_LEN("on_stdout"), &on_stdout->cb)
+      &&tv_dict_get_callback(vopts, S_LEN("on_stderr"), &on_stderr->cb)
       && tv_dict_get_callback(vopts, S_LEN("on_exit"), on_exit)) {
+    on_stdout->buffered = tv_dict_get_number(vopts, "stdout_buffered");
+    on_stderr->buffered = tv_dict_get_number(vopts, "stderr_buffered");
+    if (on_stdout->buffered && on_stdout->cb.type == kCallbackNone) {
+      on_stdout->self = vopts;
+    }
+    if (on_stderr->buffered && on_stderr->cb.type == kCallbackNone) {
+      on_stderr->self = vopts;
+    }
     vopts->dv_refcount++;
     return true;
   }
 
-  callback_free(on_stdout);
-  callback_free(on_stderr);
+  callback_reader_free(on_stdout);
+  callback_reader_free(on_stderr);
   callback_free(on_exit);
   return false;
 }
 
-static inline bool common_job_start(TerminalJobData *data, typval_T *rettv)
-{
-  Process *proc = (Process *)&data->proc;
-  if (proc->type == kProcessTypePty && proc->detach) {
-    EMSG2(_(e_invarg2), "terminal/pty job cannot be detached");
-    xfree(data->proc.pty.term_name);
-    shell_free_argv(proc->argv);
-    free_term_job_data_event((void **)&data);
-    return false;
-  }
-
-  data->id = next_chan_id++;
-  pmap_put(uint64_t)(jobs, data->id, data);
-
-  data->refcount++;
-  char *cmd = xstrdup(proc->argv[0]);
-  int status = process_spawn(proc);
-  if (status) {
-    EMSG3(_(e_jobspawn), os_strerror(status), cmd);
-    xfree(cmd);
-    if (proc->type == kProcessTypePty) {
-      xfree(data->proc.pty.term_name);
-    }
-    rettv->vval.v_number = proc->status;
-    term_job_data_decref(data);
-    return false;
-  }
-  xfree(cmd);
-
 
-  if (data->rpc) {
-    eval_format_source_name_line((char *)IObuff, sizeof(IObuff));
-    // RPC channel takes over the in/out streams.
-    channel_from_process(proc, data->id, (char *)IObuff);
-  } else {
-    wstream_init(proc->in, 0);
-    if (proc->out) {
-      rstream_init(proc->out, 0);
-      rstream_start(proc->out, on_job_stdout, data);
-    }
-  }
-
-  if (proc->err) {
-    rstream_init(proc->err, 0);
-    rstream_start(proc->err, on_job_stderr, data);
-  }
-  rettv->vval.v_number = data->id;
-  return true;
-}
-
-static inline void free_term_job_data_event(void **argv)
+static Channel *find_job(uint64_t id, bool show_error)
 {
-  TerminalJobData *data = argv[0];
-  callback_free(&data->on_stdout);
-  callback_free(&data->on_stderr);
-  callback_free(&data->on_exit);
-
-  multiqueue_free(data->events);
-  pmap_del(uint64_t)(jobs, data->id);
-  xfree(data);
-}
-
-static inline void free_term_job_data(TerminalJobData *data)
-{
-  // data->queue may still be used after this function returns(process_wait), so
-  // only free in the next event loop iteration
-  multiqueue_put(main_loop.fast_events, free_term_job_data_event, 1, data);
-}
-
-// vimscript job callbacks must be executed on Nvim main loop
-static inline void process_job_event(TerminalJobData *data, Callback *callback,
-                                     const char *type, char *buf, size_t count,
-                                     int status)
-{
-  JobEvent event_data;
-  event_data.received = NULL;
-  if (buf) {
-    event_data.received = tv_list_alloc();
-    char *ptr = buf;
-    size_t remaining = count;
-    size_t off = 0;
-
-    while (off < remaining) {
-      // append the line
-      if (ptr[off] == NL) {
-        tv_list_append_string(event_data.received, ptr, off);
-        size_t skip = off + 1;
-        ptr += skip;
-        remaining -= skip;
-        off = 0;
-        continue;
-      }
-      if (ptr[off] == NUL) {
-        // Translate NUL to NL
-        ptr[off] = NL;
+  Channel *data = find_channel(id);
+  if (!data || data->streamtype != kChannelStreamProc
+      || process_is_stopped(&data->stream.proc)) {
+    if (show_error) {
+      if (data && data->streamtype != kChannelStreamProc) {
+        EMSG(_(e_invchanjob));
+      } else {
+        EMSG(_(e_invchan));
       }
-      off++;
     }
-    tv_list_append_string(event_data.received, ptr, off);
-  } else {
-    event_data.status = status;
-  }
-  event_data.data = data;
-  event_data.callback = callback;
-  event_data.type = type;
-  on_job_event(&event_data);
-}
-
-static void on_job_stdout(Stream *stream, RBuffer *buf, size_t count,
-    void *job, bool eof)
-{
-  TerminalJobData *data = job;
-  on_job_output(stream, job, buf, count, eof, &data->on_stdout, "stdout");
-}
-
-static void on_job_stderr(Stream *stream, RBuffer *buf, size_t count,
-    void *job, bool eof)
-{
-  TerminalJobData *data = job;
-  on_job_output(stream, job, buf, count, eof, &data->on_stderr, "stderr");
-}
-
-static void on_job_output(Stream *stream, TerminalJobData *data, RBuffer *buf,
-                          size_t count, bool eof, Callback *callback,
-                          const char *type)
-{
-  if (eof) {
-    return;
-  }
-
-  // stub variable, to keep reading consistent with the order of events, only
-  // consider the count parameter.
-  size_t r;
-  char *ptr = rbuffer_read_ptr(buf, &r);
-
-  // The order here matters, the terminal must receive the data first because
-  // process_job_event will modify the read buffer(convert NULs into NLs)
-  if (data->term) {
-    terminal_receive(data->term, ptr, count);
-  }
-
-  rbuffer_consumed(buf, count);
-  if (callback->type != kCallbackNone) {
-    process_job_event(data, callback, type, ptr, count, 0);
-  }
-}
-
-static void eval_job_process_exit_cb(Process *proc, int status, void *d)
-{
-  TerminalJobData *data = d;
-  if (data->term && !data->exited) {
-    data->exited = true;
-    char msg[sizeof("\r\n[Process exited ]") + NUMBUFLEN];
-    snprintf(msg, sizeof msg, "\r\n[Process exited %d]", proc->status);
-    terminal_close(data->term, msg);
-  }
-  if (data->rpc) {
-    channel_process_exit(data->id, status);
-  }
-
-  if (data->status_ptr) {
-    *data->status_ptr = status;
-  }
-
-  process_job_event(data, &data->on_exit, "exit", NULL, 0, status);
-
-  term_job_data_decref(data);
-}
-
-static void term_write(char *buf, size_t size, void *d)
-{
-  TerminalJobData *job = d;
-  if (job->in.closed) {
-    // If the backing stream was closed abruptly, there may be write events
-    // ahead of the terminal close event. Just ignore the writes.
-    ILOG("write failed: stream is closed");
-    return;
-  }
-  WBuffer *wbuf = wstream_new_buffer(xmemdup(buf, size), size, 1, xfree);
-  wstream_write(&job->in, wbuf);
-}
-
-static void term_resize(uint16_t width, uint16_t height, void *d)
-{
-  TerminalJobData *data = d;
-  pty_process_resize(&data->proc.pty, width, height);
-}
-
-static inline void term_delayed_free(void **argv)
-{
-  TerminalJobData *j = argv[0];
-  if (j->in.pending_reqs || j->out.pending_reqs || j->err.pending_reqs) {
-    multiqueue_put(j->events, term_delayed_free, 1, j);
-    return;
-  }
-
-  terminal_destroy(j->term);
-  term_job_data_decref(j);
-}
-
-static void term_close(void *d)
-{
-  TerminalJobData *data = d;
-  if (!data->exited) {
-    data->exited = true;
-    process_stop((Process *)&data->proc);
-  }
-  multiqueue_put(data->events, term_delayed_free, 1, data);
-}
-
-static void term_job_data_decref(TerminalJobData *data)
-{
-  if (!(--data->refcount)) {
-    free_term_job_data(data);
-  }
-}
-
-static void on_job_event(JobEvent *ev)
-{
-  if (!ev->callback) {
-    return;
-  }
-
-  typval_T argv[4];
-
-  argv[0].v_type = VAR_NUMBER;
-  argv[0].v_lock = 0;
-  argv[0].vval.v_number = ev->data->id;
-
-  if (ev->received) {
-    argv[1].v_type = VAR_LIST;
-    argv[1].v_lock = 0;
-    argv[1].vval.v_list = ev->received;
-    argv[1].vval.v_list->lv_refcount++;
-  } else {
-    argv[1].v_type = VAR_NUMBER;
-    argv[1].v_lock = 0;
-    argv[1].vval.v_number = ev->status;
-  }
-
-  argv[2].v_type = VAR_STRING;
-  argv[2].v_lock = 0;
-  argv[2].vval.v_string = (uint8_t *)ev->type;
-
-  typval_T rettv = TV_INITIAL_VALUE;
-  callback_call(ev->callback, 3, argv, &rettv);
-  tv_clear(&rettv);
-}
-
-static TerminalJobData *find_job(uint64_t id)
-{
-  TerminalJobData *data = pmap_get(uint64_t)(jobs, id);
-  if (!data || data->stopped) {
     return NULL;
   }
   return data;
 }
 
+
 static void script_host_eval(char *name, typval_T *argvars, typval_T *rettv)
 {
   if (check_restricted() || check_secure()) {
@@ -22855,4 +22536,3 @@ void ex_checkhealth(exarg_T *eap)
 
   xfree(buf);
 }
-
diff --git a/src/nvim/eval.h b/src/nvim/eval.h
index 070bc35bd5..0c0a6881f6 100644
--- a/src/nvim/eval.h
+++ b/src/nvim/eval.h
@@ -7,6 +7,9 @@
 #include "nvim/eval/typval.h"
 #include "nvim/profile.h"
 #include "nvim/garray.h"
+#include "nvim/event/rstream.h"
+#include "nvim/event/wstream.h"
+#include "nvim/channel.h"
 
 #define COPYID_INC 2
 #define COPYID_MASK (~0x1)
@@ -53,6 +56,7 @@ typedef enum {
     VV_DYING,
     VV_EXCEPTION,
     VV_THROWPOINT,
+    VV_STDERR,
     VV_REG,
     VV_CMDBANG,
     VV_INSERTMODE,
diff --git a/src/nvim/eval.lua b/src/nvim/eval.lua
index 0e359fb61c..54cbc54d78 100644
--- a/src/nvim/eval.lua
+++ b/src/nvim/eval.lua
@@ -55,6 +55,8 @@ return {
     call={args={2, 3}},
     ceil={args=1, func="float_op_wrapper", data="&ceil"},
     changenr={},
+    chanclose={args={1, 2}},
+    chansend={args=2},
     char2nr={args={1, 2}},
     cindent={args=1},
     clearmatches={},
@@ -173,10 +175,10 @@ return {
     islocked={args=1},
     id={args=1},
     items={args=1},
-    jobclose={args={1, 2}},
+    jobclose={args={1, 2}, func="f_chanclose"},
     jobpid={args=1},
     jobresize={args=3},
-    jobsend={args=2},
+    jobsend={args=2, func="f_chansend"},
     jobstart={args={1, 2}},
     jobstop={args=1},
     jobwait={args={1, 2}},
@@ -273,6 +275,7 @@ return {
     sockconnect={args={2,3}},
     sort={args={1, 3}},
     soundfold={args=1},
+    stdioopen={args=1},
     spellbadword={args={0, 1}},
     spellsuggest={args={1, 3}},
     split={args={1, 3}},
diff --git a/src/nvim/eval/typval.c b/src/nvim/eval/typval.c
index 262ea922ef..4bc3a85efb 100644
--- a/src/nvim/eval/typval.c
+++ b/src/nvim/eval/typval.c
@@ -374,7 +374,7 @@ void tv_list_append_dict(list_T *const list, dict_T *const dict)
 ///                  case string is considered to be usual zero-terminated
 ///                  string or NULL “empty” string.
 void tv_list_append_string(list_T *const l, const char *const str,
-                           const ptrdiff_t len)
+                           const ssize_t len)
   FUNC_ATTR_NONNULL_ARG(1)
 {
   if (str == NULL) {
@@ -824,7 +824,7 @@ void tv_dict_watcher_add(dict_T *const dict, const char *const key_pattern,
 /// @param[in]  cb2  Second callback to check.
 ///
 /// @return True if they are equal, false otherwise.
-bool tv_callback_equal(const Callback *const cb1, const Callback *const cb2)
+bool tv_callback_equal(const Callback *cb1, const Callback *cb2)
   FUNC_ATTR_NONNULL_ALL FUNC_ATTR_WARN_UNUSED_RESULT
 {
   if (cb1->type != cb2->type) {
@@ -843,10 +843,31 @@ bool tv_callback_equal(const Callback *const cb1, const Callback *const cb2)
       return true;
     }
   }
-  assert(false);
+  abort();
   return false;
 }
 
+/// Unref/free callback
+void callback_free(Callback *callback)
+  FUNC_ATTR_NONNULL_ALL
+{
+  switch (callback->type) {
+    case kCallbackFuncref: {
+      func_unref(callback->data.funcref);
+      xfree(callback->data.funcref);
+      break;
+    }
+    case kCallbackPartial: {
+      partial_unref(callback->data.partial);
+      break;
+    }
+    case kCallbackNone: {
+      break;
+    }
+  }
+  callback->type = kCallbackNone;
+}
+
 /// Remove watcher from a dictionary
 ///
 /// @param  dict  Dictionary to remove watcher from.
diff --git a/src/nvim/event/libuv_process.c b/src/nvim/event/libuv_process.c
index 758b35796e..c101cb1bb9 100644
--- a/src/nvim/event/libuv_process.c
+++ b/src/nvim/event/libuv_process.c
@@ -46,22 +46,22 @@ int libuv_process_spawn(LibuvProcess *uvproc)
   uvproc->uvstdio[2].flags = UV_IGNORE;
   uvproc->uv.data = proc;
 
-  if (proc->in) {
+  if (!proc->in.closed) {
     uvproc->uvstdio[0].flags = UV_CREATE_PIPE | UV_READABLE_PIPE;
     uvproc->uvstdio[0].data.stream = STRUCT_CAST(uv_stream_t,
-                                                 &proc->in->uv.pipe);
+                                                 &proc->in.uv.pipe);
   }
 
-  if (proc->out) {
+  if (!proc->out.closed) {
     uvproc->uvstdio[1].flags = UV_CREATE_PIPE | UV_WRITABLE_PIPE;
     uvproc->uvstdio[1].data.stream = STRUCT_CAST(uv_stream_t,
-                                                 &proc->out->uv.pipe);
+                                                 &proc->out.uv.pipe);
   }
 
-  if (proc->err) {
+  if (!proc->err.closed) {
     uvproc->uvstdio[2].flags = UV_CREATE_PIPE | UV_WRITABLE_PIPE;
     uvproc->uvstdio[2].data.stream = STRUCT_CAST(uv_stream_t,
-                                                 &proc->err->uv.pipe);
+                                                 &proc->err.uv.pipe);
   }
 
   int status;
diff --git a/src/nvim/event/process.c b/src/nvim/event/process.c
index 41e793500a..4eb2dd0baf 100644
--- a/src/nvim/event/process.c
+++ b/src/nvim/event/process.c
@@ -25,28 +25,28 @@
 // For pty processes SIGTERM is sent first (in case SIGHUP was not enough).
 #define KILL_TIMEOUT_MS 2000
 
-#define CLOSE_PROC_STREAM(proc, stream) \
-  do { \
-    if (proc->stream && !proc->stream->closed) { \
-      stream_close(proc->stream, NULL, NULL); \
-    } \
-  } while (0)
-
 static bool process_is_tearing_down = false;
 
 /// @returns zero on success, or negative error code
-int process_spawn(Process *proc) FUNC_ATTR_NONNULL_ALL
+int process_spawn(Process *proc, bool in, bool out, bool err)
+  FUNC_ATTR_NONNULL_ALL
 {
-  if (proc->in) {
-    uv_pipe_init(&proc->loop->uv, &proc->in->uv.pipe, 0);
+  if (in) {
+    uv_pipe_init(&proc->loop->uv, &proc->in.uv.pipe, 0);
+  } else {
+    proc->in.closed = true;
   }
 
-  if (proc->out) {
-    uv_pipe_init(&proc->loop->uv, &proc->out->uv.pipe, 0);
+  if (out) {
+    uv_pipe_init(&proc->loop->uv, &proc->out.uv.pipe, 0);
+  } else {
+    proc->out.closed = true;
   }
 
-  if (proc->err) {
-    uv_pipe_init(&proc->loop->uv, &proc->err->uv.pipe, 0);
+  if (err) {
+    uv_pipe_init(&proc->loop->uv, &proc->err.uv.pipe, 0);
+  } else {
+    proc->err.closed = true;
   }
 
   int status;
@@ -62,14 +62,14 @@ int process_spawn(Process *proc) FUNC_ATTR_NONNULL_ALL
   }
 
   if (status) {
-    if (proc->in) {
-      uv_close((uv_handle_t *)&proc->in->uv.pipe, NULL);
+    if (in) {
+      uv_close((uv_handle_t *)&proc->in.uv.pipe, NULL);
     }
-    if (proc->out) {
-      uv_close((uv_handle_t *)&proc->out->uv.pipe, NULL);
+    if (out) {
+      uv_close((uv_handle_t *)&proc->out.uv.pipe, NULL);
     }
-    if (proc->err) {
-      uv_close((uv_handle_t *)&proc->err->uv.pipe, NULL);
+    if (err) {
+      uv_close((uv_handle_t *)&proc->err.uv.pipe, NULL);
     }
 
     if (proc->type == kProcessTypeUv) {
@@ -82,30 +82,27 @@ int process_spawn(Process *proc) FUNC_ATTR_NONNULL_ALL
     return status;
   }
 
-  if (proc->in) {
-    stream_init(NULL, proc->in, -1,
-                STRUCT_CAST(uv_stream_t, &proc->in->uv.pipe));
-    proc->in->events = proc->events;
-    proc->in->internal_data = proc;
-    proc->in->internal_close_cb = on_process_stream_close;
+  if (in) {
+    stream_init(NULL, &proc->in, -1,
+                STRUCT_CAST(uv_stream_t, &proc->in.uv.pipe));
+    proc->in.internal_data = proc;
+    proc->in.internal_close_cb = on_process_stream_close;
     proc->refcount++;
   }
 
-  if (proc->out) {
-    stream_init(NULL, proc->out, -1,
-                STRUCT_CAST(uv_stream_t, &proc->out->uv.pipe));
-    proc->out->events = proc->events;
-    proc->out->internal_data = proc;
-    proc->out->internal_close_cb = on_process_stream_close;
+  if (out) {
+    stream_init(NULL, &proc->out, -1,
+                STRUCT_CAST(uv_stream_t, &proc->out.uv.pipe));
+    proc->out.internal_data = proc;
+    proc->out.internal_close_cb = on_process_stream_close;
     proc->refcount++;
   }
 
-  if (proc->err) {
-    stream_init(NULL, proc->err, -1,
-                STRUCT_CAST(uv_stream_t, &proc->err->uv.pipe));
-    proc->err->events = proc->events;
-    proc->err->internal_data = proc;
-    proc->err->internal_close_cb = on_process_stream_close;
+  if (err) {
+    stream_init(NULL, &proc->err, -1,
+                STRUCT_CAST(uv_stream_t, &proc->err.uv.pipe));
+    proc->err.internal_data = proc;
+    proc->err.internal_close_cb = on_process_stream_close;
     proc->refcount++;
   }
 
@@ -136,27 +133,11 @@ void process_teardown(Loop *loop) FUNC_ATTR_NONNULL_ALL
   pty_process_teardown(loop);
 }
 
-// Wrappers around `stream_close` that protect against double-closing.
 void process_close_streams(Process *proc) FUNC_ATTR_NONNULL_ALL
 {
-  process_close_in(proc);
-  process_close_out(proc);
-  process_close_err(proc);
-}
-
-void process_close_in(Process *proc) FUNC_ATTR_NONNULL_ALL
-{
-  CLOSE_PROC_STREAM(proc, in);
-}
-
-void process_close_out(Process *proc) FUNC_ATTR_NONNULL_ALL
-{
-  CLOSE_PROC_STREAM(proc, out);
-}
-
-void process_close_err(Process *proc) FUNC_ATTR_NONNULL_ALL
-{
-  CLOSE_PROC_STREAM(proc, err);
+  stream_may_close(&proc->in);
+  stream_may_close(&proc->out);
+  stream_may_close(&proc->err);
 }
 
 /// Synchronously wait for a process to finish
@@ -164,16 +145,15 @@ void process_close_err(Process *proc) FUNC_ATTR_NONNULL_ALL
 /// @param process  Process instance
 /// @param ms       Time in milliseconds to wait for the process.
 ///                 0 for no wait. -1 to wait until the process quits.
-/// @return Exit code of the process.
+/// @return Exit code of the process. proc->status will have the same value.
 ///         -1 if the timeout expired while the process is still running.
 ///         -2 if the user interruped the wait.
 int process_wait(Process *proc, int ms, MultiQueue *events)
   FUNC_ATTR_NONNULL_ARG(1)
 {
-  int status = -1;  // default
   bool interrupted = false;
   if (!proc->refcount) {
-    status = proc->status;
+    int status = proc->status;
     LOOP_PROCESS_EVENTS(proc->loop, proc->events, 0);
     return status;
   }
@@ -209,7 +189,9 @@ int process_wait(Process *proc, int ms, MultiQueue *events)
   if (proc->refcount == 1) {
     // Job exited, collect status and manually invoke close_cb to free the job
     // resources
-    status = interrupted ? -2 : proc->status;
+    if (interrupted) {
+      proc->status = -2;
+    }
     decref(proc);
     if (events) {
       // the decref call created an exit event, process it now
@@ -219,7 +201,7 @@ int process_wait(Process *proc, int ms, MultiQueue *events)
     proc->refcount--;
   }
 
-  return status;
+  return proc->status;
 }
 
 /// Ask a process to terminate and eventually kill if it doesn't respond
@@ -233,8 +215,9 @@ void process_stop(Process *proc) FUNC_ATTR_NONNULL_ALL
   switch (proc->type) {
     case kProcessTypeUv:
       // Close the process's stdin. If the process doesn't close its own
-      // stdout/stderr, they will be closed when it exits (voluntarily or not).
-      process_close_in(proc);
+      // stdout/stderr, they will be closed when it exits(possibly due to being
+      // terminated after a timeout)
+      stream_may_close(&proc->in);
       ILOG("Sending SIGTERM to pid %d", proc->pid);
       uv_kill(proc->pid, SIGTERM);
       break;
@@ -375,15 +358,15 @@ static void flush_stream(Process *proc, Stream *stream)
 
     // Poll for data and process the generated events.
     loop_poll_events(proc->loop, 0);
-    if (proc->events) {
-        multiqueue_process_events(proc->events);
+    if (stream->events) {
+        multiqueue_process_events(stream->events);
     }
 
     // Stream can be closed if it is empty.
     if (num_bytes == stream->num_bytes) {
-      if (stream->read_cb) {
+      if (stream->read_cb && !stream->did_eof) {
         // Stream callback could miss EOF handling if a child keeps the stream
-        // open.
+        // open. But only send EOF if we haven't already.
         stream->read_cb(stream, stream->buffer, 0, stream->cb_data, true);
       }
       break;
@@ -395,8 +378,8 @@ static void process_close_handles(void **argv)
 {
   Process *proc = argv[0];
 
-  flush_stream(proc, proc->out);
-  flush_stream(proc, proc->err);
+  flush_stream(proc, &proc->out);
+  flush_stream(proc, &proc->err);
 
   process_close_streams(proc);
   process_close(proc);
diff --git a/src/nvim/event/process.h b/src/nvim/event/process.h
index 5c00e8e7ec..033ce3604b 100644
--- a/src/nvim/event/process.h
+++ b/src/nvim/event/process.h
@@ -23,13 +23,14 @@ struct process {
   uint64_t stopped_time;
   const char *cwd;
   char **argv;
-  Stream *in, *out, *err;
+  Stream in, out, err;
   process_exit_cb cb;
   internal_process_cb internal_exit_cb, internal_close_cb;
   bool closed, detach;
   MultiQueue *events;
 };
 
+
 static inline Process process_init(Loop *loop, ProcessType type, void *data)
 {
   return (Process) {
@@ -38,14 +39,14 @@ static inline Process process_init(Loop *loop, ProcessType type, void *data)
     .loop = loop,
     .events = NULL,
     .pid = 0,
-    .status = 0,
+    .status = -1,
     .refcount = 0,
     .stopped_time = 0,
     .cwd = NULL,
     .argv = NULL,
-    .in = NULL,
-    .out = NULL,
-    .err = NULL,
+    .in = { .closed = false },
+    .out = { .closed = false },
+    .err = { .closed = false },
     .cb = NULL,
     .closed = false,
     .internal_close_cb = NULL,
@@ -54,6 +55,11 @@ static inline Process process_init(Loop *loop, ProcessType type, void *data)
   };
 }
 
+static inline bool process_is_stopped(Process *proc)
+{
+  return proc->stopped_time != 0;
+}
+
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "event/process.h.generated.h"
 #endif
diff --git a/src/nvim/event/rstream.c b/src/nvim/event/rstream.c
index 2c4db08b30..e0500ba828 100644
--- a/src/nvim/event/rstream.c
+++ b/src/nvim/event/rstream.c
@@ -105,20 +105,20 @@ static void read_cb(uv_stream_t *uvstream, ssize_t cnt, const uv_buf_t *buf)
 {
   Stream *stream = uvstream->data;
 
-  if (cnt > 0) {
-    stream->num_bytes += (size_t)cnt;
-  }
-
   if (cnt <= 0) {
-    if (cnt != UV_ENOBUFS
-        // cnt == 0 means libuv asked for a buffer and decided it wasn't needed:
-        // http://docs.libuv.org/en/latest/stream.html#c.uv_read_start.
-        //
-        // We don't need to do anything with the RBuffer because the next call
-        // to `alloc_cb` will return the same unused pointer(`rbuffer_produced`
-        // won't be called)
-        && cnt != 0) {
-      DLOG("closing Stream: %p: %s (%s)", stream,
+    // cnt == 0 means libuv asked for a buffer and decided it wasn't needed:
+    // http://docs.libuv.org/en/latest/stream.html#c.uv_read_start.
+    //
+    // We don't need to do anything with the RBuffer because the next call
+    // to `alloc_cb` will return the same unused pointer(`rbuffer_produced`
+    // won't be called)
+    if (cnt == UV_ENOBUFS || cnt == 0) {
+      return;
+    } else if (cnt == UV_EOF && uvstream->type == UV_TTY) {
+      // The TTY driver might signal TTY without closing the stream
+      invoke_read_cb(stream, 0, true);
+    } else {
+      DLOG("Closing Stream (%p): %s (%s)", stream,
            uv_err_name((int)cnt), os_strerror((int)cnt));
       // Read error or EOF, either way stop the stream and invoke the callback
       // with eof == true
@@ -130,6 +130,7 @@ static void read_cb(uv_stream_t *uvstream, ssize_t cnt, const uv_buf_t *buf)
 
   // at this point we're sure that cnt is positive, no error occurred
   size_t nread = (size_t)cnt;
+  stream->num_bytes += nread;
   // Data was already written, so all we need is to update 'wpos' to reflect
   // the space actually used in the buffer.
   rbuffer_produced(stream->buffer, nread);
@@ -187,6 +188,7 @@ static void read_event(void **argv)
   if (stream->read_cb) {
     size_t count = (uintptr_t)argv[1];
     bool eof = (uintptr_t)argv[2];
+    stream->did_eof = eof;
     stream->read_cb(stream, stream->buffer, count, stream->cb_data, eof);
   }
   stream->pending_reqs--;
diff --git a/src/nvim/event/stream.c b/src/nvim/event/stream.c
index 7c865bfe1e..ba25b76ec7 100644
--- a/src/nvim/event/stream.c
+++ b/src/nvim/event/stream.c
@@ -92,6 +92,13 @@ void stream_close(Stream *stream, stream_close_cb on_stream_close, void *data)
   }
 }
 
+void stream_may_close(Stream *stream)
+{
+  if (!stream->closed) {
+    stream_close(stream, NULL, NULL);
+  }
+}
+
 void stream_close_handle(Stream *stream)
   FUNC_ATTR_NONNULL_ALL
 {
diff --git a/src/nvim/event/stream.h b/src/nvim/event/stream.h
index d27497e4a4..e713323f5c 100644
--- a/src/nvim/event/stream.h
+++ b/src/nvim/event/stream.h
@@ -14,10 +14,7 @@ typedef struct stream Stream;
 ///
 /// @param stream The Stream instance
 /// @param rbuffer The associated RBuffer instance
-/// @param count Number of bytes to read. This must be respected if keeping
-///              the order of events is a requirement. This is because events
-///              may be queued and only processed later when more data is copied
-///              into to the buffer, so one read may starve another.
+/// @param count Number of bytes that was read.
 /// @param data User-defined data
 /// @param eof If the stream reached EOF.
 typedef void (*stream_read_cb)(Stream *stream, RBuffer *buf, size_t count,
@@ -33,6 +30,8 @@ typedef void (*stream_write_cb)(Stream *stream, void *data, int status);
 typedef void (*stream_close_cb)(Stream *stream, void *data);
 
 struct stream {
+  bool closed;
+  bool did_eof;
   union {
     uv_pipe_t pipe;
     uv_tcp_t tcp;
@@ -52,7 +51,6 @@ struct stream {
   size_t maxmem;
   size_t pending_reqs;
   size_t num_bytes;
-  bool closed;
   MultiQueue *events;
 };
 
diff --git a/src/nvim/globals.h b/src/nvim/globals.h
index 1ff0f7eb89..dcb8b40973 100644
--- a/src/nvim/globals.h
+++ b/src/nvim/globals.h
@@ -1074,11 +1074,17 @@ EXTERN char_u e_invexpr2[] INIT(= N_("E15: Invalid expression: %s"));
 EXTERN char_u e_invrange[] INIT(= N_("E16: Invalid range"));
 EXTERN char_u e_invcmd[] INIT(= N_("E476: Invalid command"));
 EXTERN char_u e_isadir2[] INIT(= N_("E17: \"%s\" is a directory"));
-EXTERN char_u e_invjob[] INIT(= N_("E900: Invalid job id"));
+EXTERN char_u e_invchan[] INIT(= N_("E900: Invalid channel id"));
+EXTERN char_u e_invchanjob[] INIT(= N_("E900: Invalid channel id: not a job"));
 EXTERN char_u e_jobtblfull[] INIT(= N_("E901: Job table is full"));
 EXTERN char_u e_jobspawn[] INIT(= N_(
-        "E903: Process failed to start: %s: \"%s\""));
-EXTERN char_u e_jobnotpty[] INIT(= N_("E904: Job is not connected to a pty"));
+    "E903: Process failed to start: %s: \"%s\""));
+EXTERN char_u e_channotpty[] INIT(= N_("E904: channel is not a pty"));
+EXTERN char_u e_stdiochan2[] INIT(= N_(
+    "E905: Couldn't open stdio channel: %s"));
+EXTERN char_u e_invstream[] INIT(= N_("E906: invalid stream for channel"));
+EXTERN char_u e_invstreamrpc[] INIT(= N_(
+    "E906: invalid stream for rpc channel, use 'rpc'"));
 EXTERN char_u e_libcall[] INIT(= N_("E364: Library call failed for \"%s()\""));
 EXTERN char_u e_mkdir[] INIT(= N_("E739: Cannot create directory %s: %s"));
 EXTERN char_u e_markinval[] INIT(= N_("E19: Mark has invalid line number"));
@@ -1189,9 +1195,9 @@ EXTERN char *ignoredp;
 
 // If a msgpack-rpc channel should be started over stdin/stdout
 EXTERN bool embedded_mode INIT(= false);
-
-/// next free id for a job or rpc channel
-EXTERN uint64_t next_chan_id INIT(= 1);
+// Dont try to start an user interface
+// or read/write to stdio (unless embedding)
+EXTERN bool headless_mode INIT(= false);
 
 /// Used to track the status of external functions.
 /// Currently only used for iconv().
diff --git a/src/nvim/if_cscope.c b/src/nvim/if_cscope.c
index 0f9ecdf2d7..6834e7a802 100644
--- a/src/nvim/if_cscope.c
+++ b/src/nvim/if_cscope.c
@@ -778,7 +778,6 @@ err_closing:
     if (execl("/bin/sh", "sh", "-c", cmd, (char *)NULL) == -1)
       PERROR(_("cs_create_connection exec failed"));
 
-    stream_set_blocking(input_global_fd(), true);  // normalize stream (#2598)
     exit(127);
   /* NOTREACHED */
   default:      /* parent. */
diff --git a/src/nvim/main.c b/src/nvim/main.c
index 93afe11f3a..0346414697 100644
--- a/src/nvim/main.c
+++ b/src/nvim/main.c
@@ -73,6 +73,9 @@
 #include "nvim/api/private/helpers.h"
 #include "nvim/api/private/handle.h"
 #include "nvim/api/private/dispatch.h"
+#ifndef WIN32
+# include "nvim/os/pty_process_unix.h"
+#endif
 
 /* Maximum number of commands from + or -c arguments. */
 #define MAX_ARG_CMDS 10
@@ -103,7 +106,6 @@ typedef struct {
   bool input_isatty;                    // stdin is a terminal
   bool output_isatty;                   // stdout is a terminal
   bool err_isatty;                      // stderr is a terminal
-  bool headless;                        // Do not start the builtin UI.
   int no_swap_file;                     // "-n" argument used
   int use_debug_break_level;
   int window_count;                     /* number of windows to use */
@@ -298,8 +300,8 @@ int main(int argc, char **argv)
   assert(p_ch >= 0 && Rows >= p_ch && Rows - p_ch <= INT_MAX);
   cmdline_row = (int)(Rows - p_ch);
   msg_row = cmdline_row;
-  screenalloc(false);           /* allocate screen buffers */
-  set_init_2(params.headless);
+  screenalloc(false);  // allocate screen buffers
+  set_init_2(headless_mode);
   TIME_MSG("inits 2");
 
   msg_scroll = TRUE;
@@ -311,8 +313,9 @@ int main(int argc, char **argv)
   /* Set the break level after the terminal is initialized. */
   debug_break_level = params.use_debug_break_level;
 
-  bool reading_input = !params.headless && (params.input_isatty
-      || params.output_isatty || params.err_isatty);
+  bool reading_input = !headless_mode
+                       && (params.input_isatty || params.output_isatty
+                           || params.err_isatty);
 
   if (reading_input) {
     // One of the startup commands (arguments, sourced scripts or plugins) may
@@ -448,7 +451,7 @@ int main(int argc, char **argv)
     wait_return(TRUE);
   }
 
-  if (!params.headless) {
+  if (!headless_mode) {
     // Stop reading from input stream, the UI layer will take over now.
     input_stop();
     ui_builtin_start();
@@ -809,11 +812,14 @@ static void command_line_scan(mparm_T *parmp)
             }
             mch_exit(0);
           } else if (STRICMP(argv[0] + argv_idx, "headless") == 0) {
-            parmp->headless = true;
+            headless_mode = true;
           } else if (STRICMP(argv[0] + argv_idx, "embed") == 0) {
             embedded_mode = true;
-            parmp->headless = true;
-            channel_from_stdio();
+            headless_mode = true;
+            const char *err;
+            if (!channel_from_stdio(true, CALLBACK_READER_INIT, &err)) {
+              abort();
+            }
           } else if (STRNICMP(argv[0] + argv_idx, "literal", 7) == 0) {
 #if !defined(UNIX)
             parmp->literal = TRUE;
@@ -1216,7 +1222,6 @@ static void init_params(mparm_T *paramp, int argc, char **argv)
   memset(paramp, 0, sizeof(*paramp));
   paramp->argc = argc;
   paramp->argv = argv;
-  paramp->headless = false;
   paramp->want_full_screen = true;
   paramp->use_debug_break_level = -1;
   paramp->window_count = -1;
@@ -1245,6 +1250,14 @@ static void check_and_set_isatty(mparm_T *paramp)
   stdout_isatty
     = paramp->output_isatty = os_isatty(fileno(stdout));
   paramp->err_isatty = os_isatty(fileno(stderr));
+  int tty_fd = paramp->input_isatty
+    ? OS_STDIN_FILENO
+    : (paramp->output_isatty
+       ? OS_STDOUT_FILENO
+       : (paramp->err_isatty ? OS_STDERR_FILENO : -1));
+#ifndef WIN32
+  pty_process_save_termios(tty_fd);
+#endif
   TIME_MSG("window checked");
 }
 
@@ -1387,7 +1400,7 @@ static void handle_tag(char_u *tagname)
 // When starting in Ex mode and commands come from a file, set Silent mode.
 static void check_tty(mparm_T *parmp)
 {
-  if (parmp->headless) {
+  if (headless_mode) {
     return;
   }
 
diff --git a/src/nvim/misc1.c b/src/nvim/misc1.c
index 137de84953..f7ee2950ef 100644
--- a/src/nvim/misc1.c
+++ b/src/nvim/misc1.c
@@ -2622,7 +2622,10 @@ void preserve_exit(void)
 
   // Prevent repeated calls into this method.
   if (really_exiting) {
-    stream_set_blocking(input_global_fd(), true);  //normalize stream (#2598)
+    if (input_global_fd() >= 0) {
+      // normalize stream (#2598)
+      stream_set_blocking(input_global_fd(), true);
+    }
     exit(2);
   }
 
diff --git a/src/nvim/msgpack_rpc/channel.c b/src/nvim/msgpack_rpc/channel.c
index 5efdb9a194..32781cf4d9 100644
--- a/src/nvim/msgpack_rpc/channel.c
+++ b/src/nvim/msgpack_rpc/channel.c
@@ -11,8 +11,8 @@
 #include "nvim/api/private/helpers.h"
 #include "nvim/api/vim.h"
 #include "nvim/api/ui.h"
+#include "nvim/channel.h"
 #include "nvim/msgpack_rpc/channel.h"
-#include "nvim/msgpack_rpc/server.h"
 #include "nvim/event/loop.h"
 #include "nvim/event/libuv_process.h"
 #include "nvim/event/rstream.h"
@@ -29,58 +29,14 @@
 #include "nvim/map.h"
 #include "nvim/log.h"
 #include "nvim/misc1.h"
-#include "nvim/path.h"
 #include "nvim/lib/kvec.h"
 #include "nvim/os/input.h"
 
-#define CHANNEL_BUFFER_SIZE 0xffff
-
 #if MIN_LOG_LEVEL > DEBUG_LOG_LEVEL
 #define log_client_msg(...)
 #define log_server_msg(...)
 #endif
 
-typedef enum {
-  kChannelTypeSocket,
-  kChannelTypeProc,
-  kChannelTypeStdio,
-  kChannelTypeInternal
-} ChannelType;
-
-typedef struct {
-  uint64_t request_id;
-  bool returned, errored;
-  Object result;
-} ChannelCallFrame;
-
-typedef struct {
-  uint64_t id;
-  size_t refcount;
-  PMap(cstr_t) *subscribed_events;
-  bool closed;
-  ChannelType type;
-  msgpack_unpacker *unpacker;
-  union {
-    Stream stream;  // bidirectional (socket)
-    Process *proc;
-    struct {
-      Stream in;
-      Stream out;
-    } std;
-  } data;
-  uint64_t next_request_id;
-  kvec_t(ChannelCallFrame *) call_stack;
-  MultiQueue *events;
-} Channel;
-
-typedef struct {
-  Channel *channel;
-  MsgpackRpcRequestHandler handler;
-  Array args;
-  uint64_t request_id;
-} RequestEvent;
-
-static PMap(uint64_t) *channels = NULL;
 static PMap(cstr_t) *event_strings = NULL;
 static msgpack_sbuffer out_buffer;
 
@@ -88,102 +44,44 @@ static msgpack_sbuffer out_buffer;
 # include "msgpack_rpc/channel.c.generated.h"
 #endif
 
-/// Initializes the module
-void channel_init(void)
+void rpc_init(void)
 {
   ch_before_blocking_events = multiqueue_new_child(main_loop.events);
-  channels = pmap_new(uint64_t)();
   event_strings = pmap_new(cstr_t)();
   msgpack_sbuffer_init(&out_buffer);
-  remote_ui_init();
 }
 
-/// Teardown the module
-void channel_teardown(void)
-{
-  if (!channels) {
-    return;
-  }
-
-  Channel *channel;
-
-  map_foreach_value(channels, channel, {
-    close_channel(channel);
-  });
-}
 
-/// Creates an API channel by starting a process and connecting to its
-/// stdin/stdout. stderr is handled by the job infrastructure.
-///
-/// @param proc   process object
-/// @param id     (optional) channel id
-/// @param source description of source function, rplugin name, TCP addr, etc
-///
-/// @return Channel id (> 0), on success. 0, on error.
-uint64_t channel_from_process(Process *proc, uint64_t id, char *source)
+void rpc_start(Channel *channel)
 {
-  Channel *channel = register_channel(kChannelTypeProc, id, proc->events,
-                                      source);
-  incref(channel);  // process channels are only closed by the exit_cb
-  channel->data.proc = proc;
+  channel_incref(channel);
+  channel->is_rpc = true;
+  RpcState *rpc = &channel->rpc;
+  rpc->closed = false;
+  rpc->unpacker = msgpack_unpacker_new(MSGPACK_UNPACKER_INIT_BUFFER_SIZE);
+  rpc->subscribed_events = pmap_new(cstr_t)();
+  rpc->next_request_id = 1;
+  kv_init(rpc->call_stack);
 
-  wstream_init(proc->in, 0);
-  rstream_init(proc->out, 0);
-  rstream_start(proc->out, receive_msgpack, channel);
-
-  DLOG("ch %" PRIu64 " in-stream=%p out-stream=%p", channel->id, proc->in,
-       proc->out);
+  if (channel->streamtype != kChannelStreamInternal) {
+    Stream *out = channel_outstream(channel);
+#if MIN_LOG_LEVEL <= DEBUG_LOG_LEVEL
+    Stream *in = channel_instream(channel);
+    DLOG("rpc ch %" PRIu64 " in-stream=%p out-stream=%p", channel->id, in, out);
+#endif
 
-  return channel->id;
+    rstream_start(out, receive_msgpack, channel);
+  }
 }
 
-/// Creates an API channel from a tcp/pipe socket connection
-///
-/// @param watcher The SocketWatcher ready to accept the connection
-void channel_from_connection(SocketWatcher *watcher)
-{
-  Channel *channel = register_channel(kChannelTypeSocket, 0, NULL,
-                                      watcher->addr);
-  socket_watcher_accept(watcher, &channel->data.stream);
-  incref(channel);  // close channel only after the stream is closed
-  channel->data.stream.internal_close_cb = close_cb;
-  channel->data.stream.internal_data = channel;
-  wstream_init(&channel->data.stream, 0);
-  rstream_init(&channel->data.stream, CHANNEL_BUFFER_SIZE);
-  rstream_start(&channel->data.stream, receive_msgpack, channel);
-
-  DLOG("ch %" PRIu64 " in/out-stream=%p", channel->id,
-       &channel->data.stream);
-}
 
-/// @param source description of source function, rplugin name, TCP addr, etc
-uint64_t channel_connect(bool tcp, const char *address, int timeout,
-                         char *source, const char **error)
+static Channel *find_rpc_channel(uint64_t id)
 {
-  if (!tcp) {
-    char *path = fix_fname(address);
-    if (server_owns_pipe_address(path)) {
-      // avoid deadlock
-      xfree(path);
-      return channel_create_internal();
-    }
-    xfree(path);
-  }
-
-  Channel *channel = register_channel(kChannelTypeSocket, 0, NULL, source);
-  if (!socket_connect(&main_loop, &channel->data.stream,
-                      tcp, address, timeout, error)) {
-    decref(channel);
-    return 0;
+  Channel *chan = find_channel(id);
+  if (!chan || !chan->is_rpc || chan->rpc.closed) {
+    return NULL;
   }
-
-  incref(channel);  // close channel only after the stream is closed
-  channel->data.stream.internal_close_cb = close_cb;
-  channel->data.stream.internal_data = channel;
-  wstream_init(&channel->data.stream, 0);
-  rstream_init(&channel->data.stream, CHANNEL_BUFFER_SIZE);
-  rstream_start(&channel->data.stream, receive_msgpack, channel);
-  return channel->id;
+  return chan;
 }
 
 /// Publishes an event to a channel.
@@ -192,12 +90,11 @@ uint64_t channel_connect(bool tcp, const char *address, int timeout,
 /// @param name Event name (application-defined)
 /// @param args Array of event arguments
 /// @return True if the event was sent successfully, false otherwise.
-bool channel_send_event(uint64_t id, const char *name, Array args)
+bool rpc_send_event(uint64_t id, const char *name, Array args)
 {
   Channel *channel = NULL;
 
-  if (id && (!(channel = pmap_get(uint64_t)(channels, id))
-            || channel->closed)) {
+  if (id && (!(channel = find_rpc_channel(id)))) {
     api_free_array(args);
     return false;
   }
@@ -218,29 +115,30 @@ bool channel_send_event(uint64_t id, const char *name, Array args)
 /// @param args Array with method arguments
 /// @param[out] error True if the return value is an error
 /// @return Whatever the remote method returned
-Object channel_send_call(uint64_t id,
-                         const char *method_name,
-                         Array args,
-                         Error *err)
+Object rpc_send_call(uint64_t id,
+                     const char *method_name,
+                     Array args,
+                     Error *err)
 {
   Channel *channel = NULL;
 
-  if (!(channel = pmap_get(uint64_t)(channels, id)) || channel->closed) {
+  if (!(channel = find_rpc_channel(id))) {
     api_set_error(err, kErrorTypeException, "Invalid channel: %" PRIu64, id);
     api_free_array(args);
     return NIL;
   }
 
-  incref(channel);
-  uint64_t request_id = channel->next_request_id++;
+  channel_incref(channel);
+  RpcState *rpc = &channel->rpc;
+  uint64_t request_id = rpc->next_request_id++;
   // Send the msgpack-rpc request
   send_request(channel, request_id, method_name, args);
 
   // Push the frame
   ChannelCallFrame frame = { request_id, false, false, NIL };
-  kv_push(channel->call_stack, &frame);
+  kv_push(rpc->call_stack, &frame);
   LOOP_PROCESS_EVENTS_UNTIL(&main_loop, channel->events, -1, frame.returned);
-  (void)kv_pop(channel->call_stack);
+  (void)kv_pop(rpc->call_stack);
 
   if (frame.errored) {
     if (frame.result.type == kObjectTypeString) {
@@ -265,7 +163,7 @@ Object channel_send_call(uint64_t id,
     api_free_object(frame.result);
   }
 
-  decref(channel);
+  channel_decref(channel);
 
   return frame.errored ? NIL : frame.result;
 }
@@ -274,11 +172,11 @@ Object channel_send_call(uint64_t id,
 ///
 /// @param id The channel id
 /// @param event The event type string
-void channel_subscribe(uint64_t id, char *event)
+void rpc_subscribe(uint64_t id, char *event)
 {
   Channel *channel;
 
-  if (!(channel = pmap_get(uint64_t)(channels, id)) || channel->closed) {
+  if (!(channel = find_rpc_channel(id))) {
     abort();
   }
 
@@ -289,81 +187,32 @@ void channel_subscribe(uint64_t id, char *event)
     pmap_put(cstr_t)(event_strings, event_string, event_string);
   }
 
-  pmap_put(cstr_t)(channel->subscribed_events, event_string, event_string);
+  pmap_put(cstr_t)(channel->rpc.subscribed_events, event_string, event_string);
 }
 
 /// Unsubscribes to event broadcasts
 ///
 /// @param id The channel id
 /// @param event The event type string
-void channel_unsubscribe(uint64_t id, char *event)
+void rpc_unsubscribe(uint64_t id, char *event)
 {
   Channel *channel;
 
-  if (!(channel = pmap_get(uint64_t)(channels, id)) || channel->closed) {
+  if (!(channel = find_rpc_channel(id))) {
     abort();
   }
 
   unsubscribe(channel, event);
 }
 
-/// Closes a channel
-///
-/// @param id The channel id
-/// @return true if successful, false otherwise
-bool channel_close(uint64_t id)
-{
-  Channel *channel;
-
-  if (!(channel = pmap_get(uint64_t)(channels, id)) || channel->closed) {
-    return false;
-  }
-
-  close_channel(channel);
-  return true;
-}
-
-/// Creates an API channel from stdin/stdout. Used to embed Nvim.
-void channel_from_stdio(void)
-{
-  Channel *channel = register_channel(kChannelTypeStdio, 0, NULL, NULL);
-  incref(channel);  // stdio channels are only closed on exit
-  // read stream
-  rstream_init_fd(&main_loop, &channel->data.std.in, 0, CHANNEL_BUFFER_SIZE);
-  rstream_start(&channel->data.std.in, receive_msgpack, channel);
-  // write stream
-  wstream_init_fd(&main_loop, &channel->data.std.out, 1, 0);
-
-  DLOG("ch %" PRIu64 " in-stream=%p out-stream=%p", channel->id,
-       &channel->data.std.in, &channel->data.std.out);
-}
-
-/// Creates a loopback channel. This is used to avoid deadlock
-/// when an instance connects to its own named pipe.
-uint64_t channel_create_internal(void)
-{
-  Channel *channel = register_channel(kChannelTypeInternal, 0, NULL, NULL);
-  incref(channel);  // internal channel lives until process exit
-  return channel->id;
-}
-
-void channel_process_exit(uint64_t id, int status)
-{
-  Channel *channel = pmap_get(uint64_t)(channels, id);
-
-  channel->closed = true;
-  decref(channel);
-}
-
-// rstream.c:read_event() invokes this as stream->read_cb().
 static void receive_msgpack(Stream *stream, RBuffer *rbuf, size_t c,
                             void *data, bool eof)
 {
   Channel *channel = data;
-  incref(channel);
+  channel_incref(channel);
 
   if (eof) {
-    close_channel(channel);
+    channel_close(channel->id, kChannelPartRpc, NULL);
     char buf[256];
     snprintf(buf, sizeof(buf), "ch %" PRIu64 " was closed by the client",
              channel->id);
@@ -371,30 +220,19 @@ static void receive_msgpack(Stream *stream, RBuffer *rbuf, size_t c,
     goto end;
   }
 
-  if ((chan_wstream(channel) != NULL && chan_wstream(channel)->closed)
-      || (chan_rstream(channel) != NULL && chan_rstream(channel)->closed)) {
-    char buf[256];
-    snprintf(buf, sizeof(buf),
-             "ch %" PRIu64 ": stream closed unexpectedly. "
-             "closing channel",
-             channel->id);
-    call_set_error(channel, buf, WARN_LOG_LEVEL);
-    goto end;
-  }
-
   size_t count = rbuffer_size(rbuf);
-  DLOG("ch %" PRIu64 ": parsing %u bytes from msgpack Stream: %p",
+  DLOG("ch %" PRIu64 ": parsing %zu bytes from msgpack Stream: %p",
        channel->id, count, stream);
 
   // Feed the unpacker with data
-  msgpack_unpacker_reserve_buffer(channel->unpacker, count);
-  rbuffer_read(rbuf, msgpack_unpacker_buffer(channel->unpacker), count);
-  msgpack_unpacker_buffer_consumed(channel->unpacker, count);
+  msgpack_unpacker_reserve_buffer(channel->rpc.unpacker, count);
+  rbuffer_read(rbuf, msgpack_unpacker_buffer(channel->rpc.unpacker), count);
+  msgpack_unpacker_buffer_consumed(channel->rpc.unpacker, count);
 
   parse_msgpack(channel);
 
 end:
-  decref(channel);
+  channel_decref(channel);
 }
 
 static void parse_msgpack(Channel *channel)
@@ -404,8 +242,8 @@ static void parse_msgpack(Channel *channel)
   msgpack_unpack_return result;
 
   // Deserialize everything we can.
-  while ((result = msgpack_unpacker_next(channel->unpacker, &unpacked)) ==
-      MSGPACK_UNPACK_SUCCESS) {
+  while ((result = msgpack_unpacker_next(channel->rpc.unpacker, &unpacked)) ==
+         MSGPACK_UNPACK_SUCCESS) {
     bool is_response = is_rpc_response(&unpacked.data);
     log_client_msg(channel->id, !is_response, unpacked.data);
 
@@ -431,7 +269,7 @@ static void parse_msgpack(Channel *channel)
   if (result == MSGPACK_UNPACK_NOMEM_ERROR) {
     mch_errmsg(e_outofmem);
     mch_errmsg("\n");
-    decref(channel);
+    channel_decref(channel);
     preserve_exit();
   }
 
@@ -496,7 +334,7 @@ static void handle_request(Channel *channel, msgpack_object *request)
   evdata->handler = handler;
   evdata->args = args;
   evdata->request_id = request_id;
-  incref(channel);
+  channel_incref(channel);
   if (handler.async) {
     bool is_get_mode = handler.fn == handle_nvim_get_mode;
 
@@ -534,66 +372,30 @@ static void on_request_event(void **argv)
     api_free_object(result);
   }
   api_free_array(args);
-  decref(channel);
+  channel_decref(channel);
   xfree(e);
   api_clear_error(&error);
 }
 
-/// Returns the Stream that a Channel writes to.
-static Stream *chan_wstream(Channel *chan)
-{
-  switch (chan->type) {
-    case kChannelTypeSocket:
-      return &chan->data.stream;
-    case kChannelTypeProc:
-      return chan->data.proc->in;
-    case kChannelTypeStdio:
-      return &chan->data.std.out;
-    case kChannelTypeInternal:
-      return NULL;
-  }
-  abort();
-}
-
-/// Returns the Stream that a Channel reads from.
-static Stream *chan_rstream(Channel *chan)
-{
-  switch (chan->type) {
-    case kChannelTypeSocket:
-      return &chan->data.stream;
-    case kChannelTypeProc:
-      return chan->data.proc->out;
-    case kChannelTypeStdio:
-      return &chan->data.std.in;
-    case kChannelTypeInternal:
-      return NULL;
-  }
-  abort();
-}
-
-
 static bool channel_write(Channel *channel, WBuffer *buffer)
 {
-  bool success = false;
+  bool success;
 
-  if (channel->closed) {
+  if (channel->rpc.closed) {
     wstream_release_wbuffer(buffer);
     return false;
   }
 
-  switch (channel->type) {
-    case kChannelTypeSocket:
-    case kChannelTypeProc:
-    case kChannelTypeStdio:
-      success = wstream_write(chan_wstream(channel), buffer);
-      break;
-    case kChannelTypeInternal:
-      incref(channel);
-      CREATE_EVENT(channel->events, internal_read_event, 2, channel, buffer);
-      success = true;
-      break;
+  if (channel->streamtype == kChannelStreamInternal) {
+    channel_incref(channel);
+    CREATE_EVENT(channel->events, internal_read_event, 2, channel, buffer);
+    success = true;
+  } else {
+    Stream *in = channel_instream(channel);
+    success = wstream_write(in, buffer);
   }
 
+
   if (!success) {
     // If the write failed for any reason, close the channel
     char buf[256];
@@ -613,14 +415,14 @@ static void internal_read_event(void **argv)
   Channel *channel = argv[0];
   WBuffer *buffer = argv[1];
 
-  msgpack_unpacker_reserve_buffer(channel->unpacker, buffer->size);
-  memcpy(msgpack_unpacker_buffer(channel->unpacker),
+  msgpack_unpacker_reserve_buffer(channel->rpc.unpacker, buffer->size);
+  memcpy(msgpack_unpacker_buffer(channel->rpc.unpacker),
          buffer->data, buffer->size);
-  msgpack_unpacker_buffer_consumed(channel->unpacker, buffer->size);
+  msgpack_unpacker_buffer_consumed(channel->rpc.unpacker, buffer->size);
 
   parse_msgpack(channel);
 
-  decref(channel);
+  channel_decref(channel);
   wstream_release_wbuffer(buffer);
 }
 
@@ -669,7 +471,8 @@ static void broadcast_event(const char *name, Array args)
   Channel *channel;
 
   map_foreach_value(channels, channel, {
-    if (pmap_has(cstr_t)(channel->subscribed_events, name)) {
+    if (channel->is_rpc
+        && pmap_has(cstr_t)(channel->rpc.subscribed_events, name)) {
       kv_push(subscribed, channel);
     }
   });
@@ -699,10 +502,11 @@ end:
 static void unsubscribe(Channel *channel, char *event)
 {
   char *event_string = pmap_get(cstr_t)(event_strings, event);
-  pmap_del(cstr_t)(channel->subscribed_events, event_string);
+  pmap_del(cstr_t)(channel->rpc.subscribed_events, event_string);
 
   map_foreach_value(channels, channel, {
-    if (pmap_has(cstr_t)(channel->subscribed_events, event_string)) {
+    if (channel->is_rpc
+        && pmap_has(cstr_t)(channel->rpc.subscribed_events, event_string)) {
       return;
     }
   });
@@ -712,98 +516,43 @@ static void unsubscribe(Channel *channel, char *event)
   xfree(event_string);
 }
 
-/// Close the channel streams/process and free the channel resources.
-static void close_channel(Channel *channel)
+
+/// Mark rpc state as closed, and release its reference to the channel.
+/// Don't call this directly, call channel_close(id, kChannelPartRpc, &error)
+void rpc_close(Channel *channel)
 {
-  if (channel->closed) {
+  if (channel->rpc.closed) {
     return;
   }
 
-  channel->closed = true;
+  channel->rpc.closed = true;
+  channel_decref(channel);
 
-  switch (channel->type) {
-    case kChannelTypeSocket:
-      stream_close(&channel->data.stream, NULL, NULL);
-      break;
-    case kChannelTypeProc:
-      // Only close the rpc channel part,
-      // there could be an error message on the stderr stream
-      process_close_in(channel->data.proc);
-      process_close_out(channel->data.proc);
-      break;
-    case kChannelTypeStdio:
-      stream_close(&channel->data.std.in, NULL, NULL);
-      stream_close(&channel->data.std.out, NULL, NULL);
-      multiqueue_put(main_loop.fast_events, exit_event, 1, channel);
-      return;
-    case kChannelTypeInternal:
-      // nothing to free.
-      break;
+  if (channel->streamtype == kChannelStreamStdio) {
+    multiqueue_put(main_loop.fast_events, exit_event, 0);
   }
-
-  decref(channel);
 }
 
 static void exit_event(void **argv)
 {
-  decref(argv[0]);
-
   if (!exiting) {
     mch_exit(0);
   }
 }
 
-static void free_channel(Channel *channel)
+void rpc_free(Channel *channel)
 {
   remote_ui_disconnect(channel->id);
-  pmap_del(uint64_t)(channels, channel->id);
-  msgpack_unpacker_free(channel->unpacker);
+  msgpack_unpacker_free(channel->rpc.unpacker);
 
   // Unsubscribe from all events
   char *event_string;
-  map_foreach_value(channel->subscribed_events, event_string, {
+  map_foreach_value(channel->rpc.subscribed_events, event_string, {
     unsubscribe(channel, event_string);
   });
 
-  pmap_free(cstr_t)(channel->subscribed_events);
-  kv_destroy(channel->call_stack);
-  if (channel->type != kChannelTypeProc) {
-    multiqueue_free(channel->events);
-  }
-  xfree(channel);
-}
-
-static void close_cb(Stream *stream, void *data)
-{
-  decref(data);
-}
-
-/// @param source description of source function, rplugin name, TCP addr, etc
-static Channel *register_channel(ChannelType type, uint64_t id,
-                                 MultiQueue *events, char *source)
-{
-  // Jobs and channels share the same id namespace.
-  assert(id == 0 || !pmap_get(uint64_t)(channels, id));
-  Channel *rv = xmalloc(sizeof(Channel));
-  rv->events = events ? events : multiqueue_new_child(main_loop.events);
-  rv->type = type;
-  rv->refcount = 1;
-  rv->closed = false;
-  rv->unpacker = msgpack_unpacker_new(MSGPACK_UNPACKER_INIT_BUFFER_SIZE);
-  rv->id = id > 0 ? id : next_chan_id++;
-  rv->subscribed_events = pmap_new(cstr_t)();
-  rv->next_request_id = 1;
-  kv_init(rv->call_stack);
-  pmap_put(uint64_t)(channels, rv->id, rv);
-
-  ILOG("new channel %" PRIu64 " (%s): %s", rv->id,
-       (type == kChannelTypeProc ? "proc"
-        : (type == kChannelTypeSocket ? "socket"
-           : (type == kChannelTypeStdio ? "stdio"
-              : (type == kChannelTypeInternal ? "internal" : "?")))),
-       (source ? source : "?"));
-
-  return rv;
+  pmap_free(cstr_t)(channel->rpc.subscribed_events);
+  kv_destroy(channel->rpc.call_stack);
 }
 
 static bool is_rpc_response(msgpack_object *obj)
@@ -818,15 +567,18 @@ static bool is_rpc_response(msgpack_object *obj)
 static bool is_valid_rpc_response(msgpack_object *obj, Channel *channel)
 {
   uint64_t response_id = obj->via.array.ptr[1].via.u64;
+  if (kv_size(channel->rpc.call_stack) == 0) {
+    return false;
+  }
+
   // Must be equal to the frame at the stack's bottom
-  return kv_size(channel->call_stack) && response_id
-    == kv_A(channel->call_stack, kv_size(channel->call_stack) - 1)->request_id;
+  ChannelCallFrame *frame = kv_last(channel->rpc.call_stack);
+  return response_id == frame->request_id;
 }
 
 static void complete_call(msgpack_object *obj, Channel *channel)
 {
-  ChannelCallFrame *frame = kv_A(channel->call_stack,
-                             kv_size(channel->call_stack) - 1);
+  ChannelCallFrame *frame = kv_last(channel->rpc.call_stack);
   frame->returned = true;
   frame->errored = obj->via.array.ptr[2].type != MSGPACK_OBJECT_NIL;
 
@@ -840,15 +592,15 @@ static void complete_call(msgpack_object *obj, Channel *channel)
 static void call_set_error(Channel *channel, char *msg, int loglevel)
 {
   LOG(loglevel, "RPC: %s", msg);
-  for (size_t i = 0; i < kv_size(channel->call_stack); i++) {
-    ChannelCallFrame *frame = kv_A(channel->call_stack, i);
+  for (size_t i = 0; i < kv_size(channel->rpc.call_stack); i++) {
+    ChannelCallFrame *frame = kv_A(channel->rpc.call_stack, i);
     frame->returned = true;
     frame->errored = true;
     api_free_object(frame->result);
     frame->result = STRING_OBJ(cstr_to_string(msg));
   }
 
-  close_channel(channel);
+  channel_close(channel->id, kChannelPartRpc, NULL);
 }
 
 static WBuffer *serialize_request(uint64_t channel_id,
@@ -890,18 +642,6 @@ static WBuffer *serialize_response(uint64_t channel_id,
   return rv;
 }
 
-static void incref(Channel *channel)
-{
-  channel->refcount++;
-}
-
-static void decref(Channel *channel)
-{
-  if (!(--channel->refcount)) {
-    free_channel(channel);
-  }
-}
-
 #if MIN_LOG_LEVEL <= DEBUG_LOG_LEVEL
 #define REQ "[request]  "
 #define RES "[response] "
diff --git a/src/nvim/msgpack_rpc/channel.h b/src/nvim/msgpack_rpc/channel.h
index f8fe6f129b..9ff5abdc5f 100644
--- a/src/nvim/msgpack_rpc/channel.h
+++ b/src/nvim/msgpack_rpc/channel.h
@@ -8,6 +8,7 @@
 #include "nvim/event/socket.h"
 #include "nvim/event/process.h"
 #include "nvim/vim.h"
+#include "nvim/channel.h"
 
 #define METHOD_MAXLEN 512
 
@@ -16,6 +17,7 @@
 ///       of os_inchar(), so they are processed "just-in-time".
 MultiQueue *ch_before_blocking_events;
 
+
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "msgpack_rpc/channel.h.generated.h"
 #endif
diff --git a/src/nvim/msgpack_rpc/channel_defs.h b/src/nvim/msgpack_rpc/channel_defs.h
new file mode 100644
index 0000000000..6d8362e8b7
--- /dev/null
+++ b/src/nvim/msgpack_rpc/channel_defs.h
@@ -0,0 +1,36 @@
+#ifndef NVIM_MSGPACK_RPC_CHANNEL_DEFS_H
+#define NVIM_MSGPACK_RPC_CHANNEL_DEFS_H
+
+#include <stdbool.h>
+#include <uv.h>
+#include <msgpack.h>
+
+#include "nvim/api/private/defs.h"
+#include "nvim/event/socket.h"
+#include "nvim/event/process.h"
+#include "nvim/vim.h"
+
+typedef struct Channel Channel;
+
+typedef struct {
+  uint64_t request_id;
+  bool returned, errored;
+  Object result;
+} ChannelCallFrame;
+
+typedef struct {
+  Channel *channel;
+  MsgpackRpcRequestHandler handler;
+  Array args;
+  uint64_t request_id;
+} RequestEvent;
+
+typedef struct {
+  PMap(cstr_t) *subscribed_events;
+  bool closed;
+  msgpack_unpacker *unpacker;
+  uint64_t next_request_id;
+  kvec_t(ChannelCallFrame *) call_stack;
+} RpcState;
+
+#endif  // NVIM_MSGPACK_RPC_CHANNEL_DEFS_H
diff --git a/src/nvim/option.c b/src/nvim/option.c
index f6f334f432..65ab7a54a6 100644
--- a/src/nvim/option.c
+++ b/src/nvim/option.c
@@ -115,6 +115,7 @@ static int p_bomb;
 static char_u   *p_bh;
 static char_u   *p_bt;
 static int p_bl;
+static long p_channel;
 static int p_ci;
 static int p_cin;
 static char_u   *p_cink;
@@ -4193,6 +4194,9 @@ static char *set_num_option(int opt_idx, char_u *varp, long value,
       curbuf->b_p_imsearch = B_IMODE_NONE;
     }
     p_imsearch = curbuf->b_p_imsearch;
+  } else if (pp == &p_channel || pp == &curbuf->b_p_channel) {
+    errmsg = e_invarg;
+    *pp = old_value;
   }
   /* if 'titlelen' has changed, redraw the title */
   else if (pp == &p_titlelen) {
@@ -5472,6 +5476,7 @@ static char_u *get_varp(vimoption_T *p)
   case PV_BH:     return (char_u *)&(curbuf->b_p_bh);
   case PV_BT:     return (char_u *)&(curbuf->b_p_bt);
   case PV_BL:     return (char_u *)&(curbuf->b_p_bl);
+  case PV_CHANNEL:return (char_u *)&(curbuf->b_p_channel);
   case PV_CI:     return (char_u *)&(curbuf->b_p_ci);
   case PV_CIN:    return (char_u *)&(curbuf->b_p_cin);
   case PV_CINK:   return (char_u *)&(curbuf->b_p_cink);
@@ -5773,6 +5778,7 @@ void buf_copy_options(buf_T *buf, int flags)
       buf->b_p_nf = vim_strsave(p_nf);
       buf->b_p_mps = vim_strsave(p_mps);
       buf->b_p_si = p_si;
+      buf->b_p_channel = 0;
       buf->b_p_ci = p_ci;
       buf->b_p_cin = p_cin;
       buf->b_p_cink = vim_strsave(p_cink);
diff --git a/src/nvim/option_defs.h b/src/nvim/option_defs.h
index 1f62490ab9..b16f222705 100644
--- a/src/nvim/option_defs.h
+++ b/src/nvim/option_defs.h
@@ -695,6 +695,7 @@ enum {
   , BV_BIN
   , BV_BL
   , BV_BOMB
+  , BV_CHANNEL
   , BV_CI
   , BV_CIN
   , BV_CINK
diff --git a/src/nvim/options.lua b/src/nvim/options.lua
index cb3e5ad856..dd28a765fd 100644
--- a/src/nvim/options.lua
+++ b/src/nvim/options.lua
@@ -295,6 +295,14 @@ return {
       defaults={if_true={vi="", vim=macros('CTRL_F_STR')}}
     },
     {
+      full_name='channel',
+      type='number', scope={'buffer'},
+      no_mkrc=true,
+      nodefault=true,
+      varname='p_channel',
+      defaults={if_true={vi=0}}
+    },
+    {
       full_name='charconvert', abbreviation='ccv',
       type='string', scope={'global'},
       secure=true,
diff --git a/src/nvim/os/input.c b/src/nvim/os/input.c
index 31e06ce404..7d6f2abd7f 100644
--- a/src/nvim/os/input.c
+++ b/src/nvim/os/input.c
@@ -37,7 +37,7 @@ typedef enum {
 static Stream read_stream = {.closed = true};
 static RBuffer *input_buffer = NULL;
 static bool input_eof = false;
-static int global_fd = 0;
+static int global_fd = -1;
 static int events_enabled = 0;
 static bool blocking = false;
 
diff --git a/src/nvim/os/pty_process_unix.c b/src/nvim/os/pty_process_unix.c
index ee3ab96a83..53301e4b53 100644
--- a/src/nvim/os/pty_process_unix.c
+++ b/src/nvim/os/pty_process_unix.c
@@ -36,23 +36,36 @@
 # include "os/pty_process_unix.c.generated.h"
 #endif
 
+/// termios saved at startup (for TUI) or initialized by pty_process_spawn().
+static struct termios termios_default;
+
+/// Saves the termios properties associated with `tty_fd`.
+///
+/// @param tty_fd   TTY file descriptor, or -1 if not in a terminal.
+void pty_process_save_termios(int tty_fd)
+{
+  if (tty_fd == -1 || tcgetattr(tty_fd, &termios_default) != 0) {
+    return;
+  }
+}
+
 /// @returns zero on success, or negative error code
 int pty_process_spawn(PtyProcess *ptyproc)
   FUNC_ATTR_NONNULL_ALL
 {
-  static struct termios termios;
-  if (!termios.c_cflag) {
-    init_termios(&termios);
+  if (!termios_default.c_cflag) {
+    // TODO(jkeyes): We could pass NULL to forkpty() instead ...
+    init_termios(&termios_default);
   }
 
   int status = 0;  // zero or negative error code (libuv convention)
   Process *proc = (Process *)ptyproc;
-  assert(!proc->err);
+  assert(proc->err.closed);
   uv_signal_start(&proc->loop->children_watcher, chld_handler, SIGCHLD);
   ptyproc->winsize = (struct winsize){ ptyproc->height, ptyproc->width, 0, 0 };
   uv_disable_stdio_inheritance();
   int master;
-  int pid = forkpty(&master, NULL, &termios, &ptyproc->winsize);
+  int pid = forkpty(&master, NULL, &termios_default, &ptyproc->winsize);
 
   if (pid < 0) {
     status = -errno;
@@ -83,12 +96,12 @@ int pty_process_spawn(PtyProcess *ptyproc)
     goto error;
   }
 
-  if (proc->in
-      && (status = set_duplicating_descriptor(master, &proc->in->uv.pipe))) {
+  if (!proc->in.closed
+      && (status = set_duplicating_descriptor(master, &proc->in.uv.pipe))) {
     goto error;
   }
-  if (proc->out
-      && (status = set_duplicating_descriptor(master, &proc->out->uv.pipe))) {
+  if (!proc->out.closed
+      && (status = set_duplicating_descriptor(master, &proc->out.uv.pipe))) {
     goto error;
   }
 
diff --git a/src/nvim/os/pty_process_win.c b/src/nvim/os/pty_process_win.c
index ef8a699c56..3c4839a076 100644
--- a/src/nvim/os/pty_process_win.c
+++ b/src/nvim/os/pty_process_win.c
@@ -44,7 +44,7 @@ int pty_process_spawn(PtyProcess *ptyproc)
   wchar_t *cwd = NULL;
   const char *emsg = NULL;
 
-  assert(!proc->err);
+  assert(proc->err.closed);
 
   cfg = winpty_config_new(WINPTY_FLAG_ALLOW_CURPROC_DESKTOP_CREATION, &err);
   if (cfg == NULL) {
@@ -71,20 +71,20 @@ int pty_process_spawn(PtyProcess *ptyproc)
     goto cleanup;
   }
 
-  if (proc->in != NULL) {
+  if (!proc->in.closed) {
     in_req = xmalloc(sizeof(uv_connect_t));
     uv_pipe_connect(
         in_req,
-        &proc->in->uv.pipe,
+        &proc->in.uv.pipe,
         in_name,
         pty_process_connect_cb);
   }
 
-  if (proc->out != NULL) {
+  if (!proc->out.closed) {
     out_req = xmalloc(sizeof(uv_connect_t));
     uv_pipe_connect(
         out_req,
-        &proc->out->uv.pipe,
+        &proc->out.uv.pipe,
         out_name,
         pty_process_connect_cb);
   }
@@ -228,7 +228,7 @@ static void wait_eof_timer_cb(uv_timer_t *wait_eof_timer)
   PtyProcess *ptyproc = wait_eof_timer->data;
   Process *proc = (Process *)ptyproc;
 
-  if (!proc->out || !uv_is_readable(proc->out->uvstream)) {
+  if (proc->out.closed || !uv_is_readable(proc->out.uvstream)) {
     uv_timer_stop(&ptyproc->wait_eof_timer);
     pty_process_finish2(ptyproc);
   }
diff --git a/src/nvim/os/shell.c b/src/nvim/os/shell.c
index 32e9a70e57..e32c6e05d2 100644
--- a/src/nvim/os/shell.c
+++ b/src/nvim/os/shell.c
@@ -207,16 +207,12 @@ static int do_os_system(char **argv,
   char prog[MAXPATHL];
   xstrlcpy(prog, argv[0], MAXPATHL);
 
-  Stream in, out, err;
   LibuvProcess uvproc = libuv_process_init(&main_loop, &buf);
   Process *proc = &uvproc.process;
   MultiQueue *events = multiqueue_new_child(main_loop.events);
   proc->events = events;
   proc->argv = argv;
-  proc->in = input != NULL ? &in : NULL;
-  proc->out = &out;
-  proc->err = &err;
-  int status = process_spawn(proc);
+  int status = process_spawn(proc, input != NULL, true, true);
   if (status) {
     loop_poll_events(&main_loop, 0);
     // Failed, probably 'shell' is not executable.
@@ -231,32 +227,29 @@ static int do_os_system(char **argv,
     return -1;
   }
 
-  // We want to deal with stream events as fast a possible while queueing
-  // process events, so reset everything to NULL. It prevents closing the
+  // Note: unlike process events, stream events are not queued, as we want to
+  // deal with stream events as fast a possible.  It prevents closing the
   // streams while there's still data in the OS buffer (due to the process
   // exiting before all data is read).
   if (input != NULL) {
-    proc->in->events = NULL;
-    wstream_init(proc->in, 0);
+    wstream_init(&proc->in, 0);
   }
-  proc->out->events = NULL;
-  rstream_init(proc->out, 0);
-  rstream_start(proc->out, data_cb, &buf);
-  proc->err->events = NULL;
-  rstream_init(proc->err, 0);
-  rstream_start(proc->err, data_cb, &buf);
+  rstream_init(&proc->out, 0);
+  rstream_start(&proc->out, data_cb, &buf);
+  rstream_init(&proc->err, 0);
+  rstream_start(&proc->err, data_cb, &buf);
 
   // write the input, if any
   if (input) {
     WBuffer *input_buffer = wstream_new_buffer((char *) input, len, 1, NULL);
 
-    if (!wstream_write(&in, input_buffer)) {
+    if (!wstream_write(&proc->in, input_buffer)) {
       // couldn't write, stop the process and tell the user about it
       process_stop(proc);
       return -1;
     }
     // close the input stream after everything is written
-    wstream_set_write_cb(&in, shell_write_cb, NULL);
+    wstream_set_write_cb(&proc->in, shell_write_cb, NULL);
   }
 
   // Invoke busy_start here so LOOP_PROCESS_EVENTS_UNTIL will not change the
@@ -684,10 +677,6 @@ static void shell_write_cb(Stream *stream, void *data, int status)
     msg_schedule_emsgf(_("E5677: Error writing input to shell-command: %s"),
                        uv_err_name(status));
   }
-  if (stream->closed) {  // Process may have exited before this write.
-    WLOG("stream was already closed");
-    return;
-  }
   stream_close(stream, NULL, NULL);
 }
 
diff --git a/src/nvim/os_unix.c b/src/nvim/os_unix.c
index 692bcc97f4..d7ba675b68 100644
--- a/src/nvim/os_unix.c
+++ b/src/nvim/os_unix.c
@@ -144,7 +144,9 @@ void mch_exit(int r) FUNC_ATTR_NORETURN
   if (!event_teardown() && r == 0) {
     r = 1;  // Exit with error if main_loop did not teardown gracefully.
   }
-  stream_set_blocking(input_global_fd(), true);  // normalize stream (#2598)
+  if (input_global_fd() >= 0) {
+    stream_set_blocking(input_global_fd(), true);  // normalize stream (#2598)
+  }
 
 #ifdef EXITFREE
   free_all_mem();
diff --git a/src/nvim/rbuffer.c b/src/nvim/rbuffer.c
index 18d453cbe9..df9394fbb2 100644
--- a/src/nvim/rbuffer.c
+++ b/src/nvim/rbuffer.c
@@ -121,7 +121,7 @@ char *rbuffer_read_ptr(RBuffer *buf, size_t *read_count) FUNC_ATTR_NONNULL_ALL
 {
   if (!buf->size) {
     *read_count = 0;
-    return NULL;
+    return buf->read_ptr;
   }
 
   if (buf->read_ptr < buf->write_ptr) {
diff --git a/src/nvim/terminal.c b/src/nvim/terminal.c
index 1dac9c69bd..dfa758f41e 100644
--- a/src/nvim/terminal.c
+++ b/src/nvim/terminal.c
@@ -1094,11 +1094,12 @@ static void refresh_terminal(Terminal *term)
 // Calls refresh_terminal() on all invalidated_terminals.
 static void refresh_timer_cb(TimeWatcher *watcher, void *data)
 {
+  refresh_pending = false;
   if (exiting  // Cannot redraw (requires event loop) during teardown/exit.
       // WM_LIST (^D) is not redrawn, unlike the normal wildmenu. So we must
       // skip redraws to keep it visible.
       || wild_menu_showing == WM_LIST) {
-    goto end;
+    return;
   }
   Terminal *term;
   void *stub; (void)(stub);
@@ -1113,8 +1114,6 @@ static void refresh_timer_cb(TimeWatcher *watcher, void *data)
   if (any_visible) {
     redraw(true);
   }
-end:
-  refresh_pending = false;
 }
 
 static void refresh_size(Terminal *term, buf_T *buf)