job: Allow spawning jobs connected to pseudo terminals

12 files changed, 501 insertions, 9 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 111e8b76d8..caf345de8c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -276,6 +276,8 @@ get_compile_flags(NVIM_VERSION_CFLAGS)
 
 add_subdirectory(test/includes)
 add_subdirectory(config)
+add_subdirectory(test/functional/job) # compile pty test program
+
 
 # Setup some test-related bits.  We do this after going down the tree because we
 # need some of the targets.
@@ -316,5 +318,5 @@ if(BUSTED_PRG)
       -DBUILD_DIR=${CMAKE_BINARY_DIR}
       -DTEST_TYPE=functional
       -P ${PROJECT_SOURCE_DIR}/cmake/RunTests.cmake
-    DEPENDS nvim)
+    DEPENDS nvim tty-test)
 endif()
diff --git a/src/nvim/CMakeLists.txt b/src/nvim/CMakeLists.txt
index 1c2dad6094..c59de2b5de 100644
--- a/src/nvim/CMakeLists.txt
+++ b/src/nvim/CMakeLists.txt
@@ -175,6 +175,7 @@ list(APPEND NVIM_LINK_LIBRARIES
     ${LIBTERMKEY_LIBRARIES}
     ${LIBUNIBILIUM_LIBRARIES}
     m
+    util
     ${CMAKE_THREAD_LIBS_INIT}
     )
 
diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index c2a46ed206..b826ddcc50 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -6488,8 +6488,9 @@ static struct fst {
   {"isdirectory",     1, 1, f_isdirectory},
   {"islocked",        1, 1, f_islocked},
   {"items",           1, 1, f_items},
+  {"jobresize",       3, 3, f_jobresize},
   {"jobsend",         2, 2, f_jobsend},
-  {"jobstart",        2, 3, f_jobstart},
+  {"jobstart",        2, 4, f_jobstart},
   {"jobstop",         1, 1, f_jobstop},
   {"join",            1, 2, f_join},
   {"keys",            1, 1, f_keys},
@@ -10665,6 +10666,39 @@ static void f_jobsend(typval_T *argvars, typval_T *rettv)
   rettv->vval.v_number = job_write(job, buf);
 }
 
+// "jobresize()" function
+static void f_jobresize(typval_T *argvars, typval_T *rettv)
+{
+  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_NUMBER
+      || argvars[2].v_type != VAR_NUMBER) {
+    // job id, width, height
+    EMSG(_(e_invarg));
+    return;
+  }
+
+  Job *job = job_find(argvars[0].vval.v_number);
+
+  if (!job) {
+    // Probably an invalid job id
+    EMSG(_(e_invjob));
+    return;
+  }
+
+  if (!job_resize(job, argvars[1].vval.v_number, argvars[2].vval.v_number)) {
+    EMSG(_(e_jobnotpty));
+    return;
+  }
+
+  rettv->vval.v_number = 1;
+}
+
 // "jobstart()" function
 static void f_jobstart(typval_T *argvars, typval_T *rettv)
 {
@@ -10682,8 +10716,7 @@ static void f_jobstart(typval_T *argvars, typval_T *rettv)
 
   if (argvars[0].v_type != VAR_STRING
       || argvars[1].v_type != VAR_STRING
-      || (argvars[2].v_type != VAR_LIST
-      && argvars[2].v_type != VAR_UNKNOWN)) {
+      || (argvars[2].v_type != VAR_LIST && argvars[2].v_type != VAR_UNKNOWN)) {
     // Wrong argument types
     EMSG(_(e_invarg));
     return;
@@ -10731,6 +10764,24 @@ static void f_jobstart(typval_T *argvars, typval_T *rettv)
   opts.stdout_cb = on_job_stdout;
   opts.stderr_cb = on_job_stderr;
   opts.exit_cb = on_job_exit;
+
+  if (args && argvars[3].v_type == VAR_DICT) {
+    dict_T *job_opts = argvars[3].vval.v_dict;
+    opts.pty = true;
+    uint16_t width = get_dict_number(job_opts, (uint8_t *)"width");
+    if (width > 0) {
+      opts.width = width;
+    }
+    uint16_t height = get_dict_number(job_opts, (uint8_t *)"height");
+    if (height > 0) {
+      opts.height = height;
+    }
+    char *term = (char *)get_dict_string(job_opts, (uint8_t *)"TERM", true);
+    if (term) {
+      opts.term_name = term;
+    }
+  }
+
   job_start(opts, &rettv->vval.v_number);
 
   if (rettv->vval.v_number <= 0) {
diff --git a/src/nvim/globals.h b/src/nvim/globals.h
index e6a8ee33c5..c0d5217fc2 100644
--- a/src/nvim/globals.h
+++ b/src/nvim/globals.h
@@ -1127,6 +1127,7 @@ 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_jobtblfull[] INIT(= N_("E901: Job table is full"));
 EXTERN char_u e_jobexe[] INIT(= N_("E902: \"%s\" is not an executable"));
+EXTERN char_u e_jobnotpty[] INIT(= N_("E904: Job is not connected to a pty"));
 EXTERN char_u e_libcall[] INIT(= N_("E364: Library call failed for \"%s()\""));
 EXTERN char_u e_markinval[] INIT(= N_("E19: Mark has invalid line number"));
 EXTERN char_u e_marknotset[] INIT(= N_("E20: Mark not set"));
diff --git a/src/nvim/os/job.c b/src/nvim/os/job.c
index 94bb9067ed..9855a19269 100644
--- a/src/nvim/os/job.c
+++ b/src/nvim/os/job.c
@@ -7,6 +7,7 @@
 #include "nvim/os/job.h"
 #include "nvim/os/job_defs.h"
 #include "nvim/os/job_private.h"
+#include "nvim/os/pty_process.h"
 #include "nvim/os/rstream.h"
 #include "nvim/os/rstream_defs.h"
 #include "nvim/os/wstream.h"
@@ -320,6 +321,16 @@ void *job_data(Job *job)
   return job->opts.data;
 }
 
+/// Resize the window for a pty job
+bool job_resize(Job *job, uint16_t width, uint16_t height)
+{
+  if (!job->opts.pty) {
+    return false;
+  }
+  pty_process_resize(job, width, height);
+  return true;
+}
+
 /// Iterates the table, sending SIGTERM to stopped jobs and SIGKILL to those
 /// that didn't die from SIGTERM after a while(exit_timeout is 0).
 static void job_stop_timer_cb(uv_timer_t *handle)
diff --git a/src/nvim/os/job_defs.h b/src/nvim/os/job_defs.h
index 340ef551be..ac9a37b366 100644
--- a/src/nvim/os/job_defs.h
+++ b/src/nvim/os/job_defs.h
@@ -37,6 +37,13 @@ typedef struct {
   job_exit_cb exit_cb;
   // Maximum memory used by the job's WStream
   size_t maxmem;
+  // Connect the job to a pseudo terminal
+  bool pty;
+  // Initial window dimensions if the job is connected to a pseudo terminal
+  uint16_t width, height;
+  // Value for the $TERM environment variable. A default value of "ansi" is
+  // assumed if NULL
+  char *term_name;
 } JobOptions;
 
 #define JOB_OPTIONS_INIT ((JobOptions) {                     \
@@ -46,6 +53,10 @@ typedef struct {
     .stdout_cb = NULL,                                       \
     .stderr_cb = NULL,                                       \
     .exit_cb = NULL,                                         \
-    .maxmem = 0                                              \
+    .maxmem = 0,                                             \
+    .pty = false,                                            \
+    .width = 80,                                             \
+    .height = 24,                                            \
+    .term_name = NULL                                        \
     })
 #endif  // NVIM_OS_JOB_DEFS_H
diff --git a/src/nvim/os/job_private.h b/src/nvim/os/job_private.h
index 1beaa1bd70..b1d5e13feb 100644
--- a/src/nvim/os/job_private.h
+++ b/src/nvim/os/job_private.h
@@ -8,6 +8,7 @@
 #include "nvim/os/rstream_defs.h"
 #include "nvim/os/wstream_defs.h"
 #include "nvim/os/pipe_process.h"
+#include "nvim/os/pty_process.h"
 #include "nvim/os/shell.h"
 #include "nvim/log.h"
 
@@ -45,12 +46,16 @@ extern uv_timer_t job_stop_timer;
 
 static inline bool process_spawn(Job *job)
 {
-  return pipe_process_spawn(job);
+  return job->opts.pty ? pty_process_spawn(job) : pipe_process_spawn(job);
 }
 
 static inline void process_init(Job *job)
 {
-  pipe_process_init(job);
+  if (job->opts.pty) {
+    pty_process_init(job);
+  } else {
+    pipe_process_init(job);
+  }
 }
 
 static inline void process_close(Job *job)
@@ -59,12 +64,20 @@ static inline void process_close(Job *job)
     return;
   }
   job->closed = true;
-  pipe_process_close(job);
+  if (job->opts.pty) {
+    pty_process_close(job);
+  } else {
+    pipe_process_close(job);
+  }
 }
 
 static inline void process_destroy(Job *job)
 {
-  pipe_process_destroy(job);
+  if (job->opts.pty) {
+    pty_process_destroy(job);
+  } else {
+    pipe_process_destroy(job);
+  }
 }
 
 static inline void job_exit_callback(Job *job)
diff --git a/src/nvim/os/pty_process.c b/src/nvim/os/pty_process.c
new file mode 100644
index 0000000000..bd7247c741
--- /dev/null
+++ b/src/nvim/os/pty_process.c
@@ -0,0 +1,225 @@
+// Some of the code came from pangoterm and libuv
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <unistd.h>
+#include <termios.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/ioctl.h>
+
+// forkpty is not in POSIX, so headers are platform-specific
+#if defined(__FreeBSD__)
+# include <libutil.h>
+#elif defined(__OpenBSD__) || defined(__NetBSD__) || defined(__APPLE__)
+# include <util.h>
+#else
+# include <pty.h>
+#endif
+
+#include <uv.h>
+
+#include "nvim/os/job.h"
+#include "nvim/os/job_defs.h"
+#include "nvim/os/job_private.h"
+#include "nvim/os/pty_process.h"
+#include "nvim/memory.h"
+
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# include "os/pty_process.c.generated.h"
+#endif
+
+typedef struct {
+  struct winsize winsize;
+  uv_pipe_t proc_stdin, proc_stdout, proc_stderr;
+  uv_signal_t schld;
+  int tty_fd;
+} PtyProcess;
+
+void pty_process_init(Job *job)
+{
+  PtyProcess *ptyproc = xmalloc(sizeof(PtyProcess));
+
+  if (job->opts.writable) {
+    uv_pipe_init(uv_default_loop(), &ptyproc->proc_stdin, 0);
+    ptyproc->proc_stdin.data = NULL;
+  }
+
+  if (job->opts.stdout_cb) {
+    uv_pipe_init(uv_default_loop(), &ptyproc->proc_stdout, 0);
+    ptyproc->proc_stdout.data = NULL;
+  }
+
+  if (job->opts.stderr_cb) {
+    uv_pipe_init(uv_default_loop(), &ptyproc->proc_stderr, 0);
+    ptyproc->proc_stderr.data = NULL;
+  }
+
+  job->proc_stdin = (uv_stream_t *)&ptyproc->proc_stdin;
+  job->proc_stdout = (uv_stream_t *)&ptyproc->proc_stdout;
+  job->proc_stderr = (uv_stream_t *)&ptyproc->proc_stderr;
+  job->process = ptyproc;
+}
+
+void pty_process_destroy(Job *job)
+{
+  free(job->opts.term_name);
+  free(job->process);
+  job->process = NULL;
+}
+
+bool pty_process_spawn(Job *job)
+{
+  int master;
+  PtyProcess *ptyproc = job->process;
+  ptyproc->winsize = (struct winsize){job->opts.height, job->opts.width, 0, 0};
+  struct termios termios;
+  init_termios(&termios);
+  uv_disable_stdio_inheritance();
+
+  int pid = forkpty(&master, NULL, &termios, &ptyproc->winsize);
+
+  if (pid < 0) {
+    return false;
+  } else if (pid == 0) {
+    init_child(job);
+    abort();
+  }
+
+  // make sure the master file descriptor is non blocking
+  fcntl(master, F_SETFL, fcntl(master, F_GETFL) | O_NONBLOCK);
+
+  if (job->opts.writable) {
+    uv_pipe_open(&ptyproc->proc_stdin, dup(master));
+  }
+
+  if (job->opts.stdout_cb) {
+    uv_pipe_open(&ptyproc->proc_stdout, dup(master));
+  }
+
+  if (job->opts.stderr_cb) {
+    uv_pipe_open(&ptyproc->proc_stderr, dup(master));
+  }
+
+  uv_signal_init(uv_default_loop(), &ptyproc->schld);
+  uv_signal_start(&ptyproc->schld, chld_handler, SIGCHLD);
+  ptyproc->schld.data = job;
+  ptyproc->tty_fd = master;
+  job->pid = pid;
+  return true;
+}
+
+void pty_process_close(Job *job)
+{
+  PtyProcess *ptyproc = job->process;
+  uv_signal_stop(&ptyproc->schld);
+  uv_close((uv_handle_t *)&ptyproc->schld, NULL);
+  job_close_streams(job);
+  job_decref(job);
+}
+
+void pty_process_resize(Job *job, uint16_t width, uint16_t height)
+{
+  PtyProcess *ptyproc = job->process;
+  ptyproc->winsize = (struct winsize){height, width, 0, 0};
+  ioctl(ptyproc->tty_fd, TIOCSWINSZ, &ptyproc->winsize);
+}
+
+static void init_child(Job *job)
+{
+  unsetenv("COLUMNS");
+  unsetenv("LINES");
+  unsetenv("TERMCAP");
+  unsetenv("COLORTERM");
+  unsetenv("COLORFGBG");
+
+  signal(SIGCHLD, SIG_DFL);
+  signal(SIGHUP, SIG_DFL);
+  signal(SIGINT, SIG_DFL);
+  signal(SIGQUIT, SIG_DFL);
+  signal(SIGTERM, SIG_DFL);
+  signal(SIGALRM, SIG_DFL);
+
+  setenv("TERM", job->opts.term_name ? job->opts.term_name : "ansi", 1);
+  execvp(job->opts.argv[0], job->opts.argv);
+  fprintf(stderr, "execvp failed: %s\n", strerror(errno));
+}
+
+static void chld_handler(uv_signal_t *handle, int signum)
+{
+  Job *job = handle->data;
+  int stat = 0;
+
+  if (waitpid(job->pid, &stat, 0) < 0) {
+    fprintf(stderr, "Waiting for pid %d failed: %s\n", job->pid,
+        strerror(errno));
+    return;
+  }
+
+  if (WIFSTOPPED(stat) || WIFCONTINUED(stat)) {
+    // Did not exit
+    return;
+  }
+
+  if (WIFEXITED(stat)) {
+    job->status = WEXITSTATUS(stat);
+  } else if (WIFSIGNALED(stat)) {
+    job->status = WTERMSIG(stat);
+  }
+
+  pty_process_close(job);
+}
+
+static void init_termios(struct termios *termios)
+{
+  memset(termios, 0, sizeof(struct termios));
+  // Taken from pangoterm
+  termios->c_iflag = ICRNL|IXON;
+  termios->c_oflag = OPOST|ONLCR|TAB0;
+  termios->c_cflag = CS8|CREAD;
+  termios->c_lflag = ISIG|ICANON|IEXTEN|ECHO|ECHOE|ECHOK;
+
+  cfsetspeed(termios, 38400);
+
+#ifdef IUTF8
+  termios->c_iflag |= IUTF8;
+#endif
+#ifdef NL0
+  termios->c_oflag |= NL0;
+#endif
+#ifdef CR0
+  termios->c_oflag |= CR0;
+#endif
+#ifdef BS0
+  termios->c_oflag |= BS0;
+#endif
+#ifdef VT0
+  termios->c_oflag |= VT0;
+#endif
+#ifdef FF0
+  termios->c_oflag |= FF0;
+#endif
+#ifdef ECHOCTL
+  termios->c_lflag |= ECHOCTL;
+#endif
+#ifdef ECHOKE
+  termios->c_lflag |= ECHOKE;
+#endif
+
+  termios->c_cc[VINTR]    = 0x1f & 'C';
+  termios->c_cc[VQUIT]    = 0x1f & '\\';
+  termios->c_cc[VERASE]   = 0x7f;
+  termios->c_cc[VKILL]    = 0x1f & 'U';
+  termios->c_cc[VEOF]     = 0x1f & 'D';
+  termios->c_cc[VEOL]     = _POSIX_VDISABLE;
+  termios->c_cc[VEOL2]    = _POSIX_VDISABLE;
+  termios->c_cc[VSTART]   = 0x1f & 'Q';
+  termios->c_cc[VSTOP]    = 0x1f & 'S';
+  termios->c_cc[VSUSP]    = 0x1f & 'Z';
+  termios->c_cc[VREPRINT] = 0x1f & 'R';
+  termios->c_cc[VWERASE]  = 0x1f & 'W';
+  termios->c_cc[VLNEXT]   = 0x1f & 'V';
+  termios->c_cc[VMIN]     = 1;
+  termios->c_cc[VTIME]    = 0;
+}
diff --git a/src/nvim/os/pty_process.h b/src/nvim/os/pty_process.h
new file mode 100644
index 0000000000..62fcd1671f
--- /dev/null
+++ b/src/nvim/os/pty_process.h
@@ -0,0 +1,7 @@
+#ifndef NVIM_OS_PTY_PROCESS_H
+#define NVIM_OS_PTY_PROCESS_H
+
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# include "os/pty_process.h.generated.h"
+#endif
+#endif  // NVIM_OS_PTY_PROCESS_H
diff --git a/test/functional/job/CMakeLists.txt b/test/functional/job/CMakeLists.txt
new file mode 100644
index 0000000000..14ec287816
--- /dev/null
+++ b/test/functional/job/CMakeLists.txt
@@ -0,0 +1,2 @@
+add_executable(tty-test tty-test.c)
+target_link_libraries(tty-test ${LIBUV_LIBRARIES})
diff --git a/test/functional/job/job_spec.lua b/test/functional/job/job_spec.lua
index b87c3a827b..0051de09e1 100644
--- a/test/functional/job/job_spec.lua
+++ b/test/functional/job/job_spec.lua
@@ -4,6 +4,7 @@ local clear, nvim, eq, neq, ok, expect, eval, next_message, run, stop, session
   = helpers.clear, helpers.nvim, helpers.eq, helpers.neq, helpers.ok,
   helpers.expect, helpers.eval, helpers.next_message, helpers.run,
   helpers.stop, helpers.session
+local insert = helpers.insert
 
 local channel = nvim('get_api_info')[1]
 
@@ -124,4 +125,57 @@ describe('jobs', function()
     eq({'notification', 'j', {{jobid, 'stdout', {'abcdef'}}}}, next_message())
     eq({'notification', 'j', {{jobid, 'exit'}}}, next_message())
   end)
+
+  describe('running tty-test program', function()
+    local function next_chunk()
+      local rv = ''
+      while true do
+        local msg = next_message()
+        local data = msg[3][1]
+        for i = 1, #data do
+          data[i] = data[i]:gsub('\n', '\000')
+        end
+        rv = table.concat(data, '\n')
+        rv = rv:gsub('\r\n$', '')
+        if rv ~= '' then
+          break
+        end
+      end
+      return rv
+    end
+
+    local function send(str)
+      nvim('command', 'call jobsend(j, "'..str..'")')
+    end
+
+    before_each(function() 
+      -- the full path to tty-test seems to be required when running on travis.
+      insert('build/bin/tty-test')
+      nvim('command', 'let exec = expand("<cfile>:p")')
+      nvim('command', notify_str('v:job_data[1]', 'get(v:job_data, 2)'))
+      nvim('command', "let j = jobstart('xxx', exec, [], {})")
+      eq('tty ready', next_chunk())
+    end)
+
+    it('echoing input', function()
+      send('test')
+      -- the tty driver will echo input by default
+      eq('test', next_chunk())
+    end)
+
+    it('resizing window', function()
+      nvim('command', 'call jobresize(j, 40, 10)')
+      eq('screen resized. rows: 10, columns: 40', next_chunk())
+      nvim('command', 'call jobresize(j, 10, 40)')
+      eq('screen resized. rows: 40, columns: 10', next_chunk())
+    end)
+
+    it('preprocessing ctrl+c with terminal driver', function()
+      send('\\<c-c>')
+      eq('^Cinterrupt received, press again to exit', next_chunk())
+      send('\\<c-c>')
+      eq('^Ctty done', next_chunk())
+      eq({'notification', 'exit', {0}}, next_message())
+    end)
+  end)
 end)
diff --git a/test/functional/job/tty-test.c b/test/functional/job/tty-test.c
new file mode 100644
index 0000000000..25e76840aa
--- /dev/null
+++ b/test/functional/job/tty-test.c
@@ -0,0 +1,114 @@
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <uv.h>
+
+#ifdef _WIN32
+#include <windows.h>
+bool owns_tty(void)
+{
+  HWND consoleWnd = GetConsoleWindow();
+  DWORD dwProcessId;
+  GetWindowThreadProcessId(consoleWnd, &dwProcessId);
+  return GetCurrentProcessId() == dwProcessId;
+}
+#else
+bool owns_tty(void)
+{
+  // TODO: Check if the process is the session leader
+  return true;
+}
+#endif
+
+#define is_terminal(stream) (uv_guess_handle(fileno(stream)) == UV_TTY)
+#define BUF_SIZE 0xfff
+
+static void walk_cb(uv_handle_t *handle, void *arg) {
+  if (!uv_is_closing(handle)) {
+    uv_close(handle, NULL);
+  }
+}
+
+static void sigwinch_cb(uv_signal_t *handle, int signum)
+{
+  int width, height;
+  uv_tty_t *tty = handle->data;
+  uv_tty_get_winsize(tty, &width, &height);
+  fprintf(stderr, "screen resized. rows: %d, columns: %d\n", height, width);
+}
+
+static void sigint_cb(uv_signal_t *handle, int signum)
+{
+  bool *interrupted = handle->data;
+
+  if (*interrupted) {
+    uv_walk(uv_default_loop(), walk_cb, NULL);
+    return;
+  }
+
+  *interrupted = true;
+  fprintf(stderr, "interrupt received, press again to exit\n");
+}
+
+static void alloc_cb(uv_handle_t *handle, size_t suggested, uv_buf_t *buf)
+{
+  buf->len = BUF_SIZE;
+  buf->base = malloc(BUF_SIZE);
+}
+
+static void read_cb(uv_stream_t *stream, ssize_t cnt, const uv_buf_t *buf)
+{
+  if (cnt <= 0) {
+    uv_read_stop(stream);
+    return;
+  }
+
+  fprintf(stderr, "received data: ");
+  uv_loop_t write_loop;
+  uv_loop_init(&write_loop);
+  uv_tty_t out;
+  uv_tty_init(&write_loop, &out, 1, 0);
+  uv_write_t req;
+  uv_buf_t b = {.base = buf->base, .len = buf->len};
+  uv_write(&req, (uv_stream_t *)&out, &b, 1, NULL);
+  uv_run(&write_loop, UV_RUN_DEFAULT);
+  uv_close((uv_handle_t *)&out, NULL);
+  uv_run(&write_loop, UV_RUN_DEFAULT);
+  if (uv_loop_close(&write_loop)) {
+    abort();
+  }
+  free(buf->base);
+}
+
+int main(int argc, char **argv)
+{
+  if (!is_terminal(stdin)) {
+    fprintf(stderr, "stdin is not a terminal\n");
+    exit(2);
+  }
+
+  if (!is_terminal(stdout)) {
+    fprintf(stderr, "stdout is not a terminal\n");
+    exit(2);
+  }
+
+  if (!is_terminal(stderr)) {
+    fprintf(stderr, "stderr is not a terminal\n");
+    exit(2);
+  }
+
+  bool interrupted = false;
+  fprintf(stderr, "tty ready\n");
+  uv_tty_t tty;
+  uv_tty_init(uv_default_loop(), &tty, fileno(stderr), 1);
+  uv_read_start((uv_stream_t *)&tty, alloc_cb, read_cb);
+  uv_signal_t sigwinch_watcher, sigint_watcher;
+  uv_signal_init(uv_default_loop(), &sigwinch_watcher);
+  sigwinch_watcher.data = &tty;
+  uv_signal_start(&sigwinch_watcher, sigwinch_cb, SIGWINCH);
+  uv_signal_init(uv_default_loop(), &sigint_watcher);
+  sigint_watcher.data = &interrupted;
+  uv_signal_start(&sigint_watcher, sigint_cb, SIGINT);
+  uv_run(uv_default_loop(), UV_RUN_DEFAULT);
+  fprintf(stderr, "tty done\n");
+}