prim_tty_nif.c

/*
 * %CopyrightBegin%
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Copyright Ericsson AB 2022-2026. All Rights Reserved.
 * Copyright Ericsson 2015-2024. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * %CopyrightEnd%
 */

/*
 * Purpose:  NIF library for interacting with the tty
 *
 */

#define STATIC_ERLANG_NIF 1

#ifndef WANT_NONBLOCKING
#define WANT_NONBLOCKING
#endif

#include "config.h"
#include "sys.h"
#include "erl_nif.h"
#include "erl_driver.h"

#include <errno.h>
#include <string.h>
#include <ctype.h>
#include <wchar.h>
#include <stdio.h>
#include <signal.h>
#include <locale.h>
#if defined(HAVE_TERMCAP)
#include <termios.h>
#if defined(HAVE_NCURSES_CURSES_H)
#include <ncurses/curses.h>
#include <ncurses/term.h>
#elif defined(HAVE_CURSES_H) && defined(HAVE_TERM_H)
#include <curses.h>
#include <term.h>
#else
/* We detected TERMCAP support, but could not find the correct headers to include */
#undef HAVE_TERMCAP
#endif
#endif
#ifndef __WIN32__
#include <unistd.h>
#include <sys/ioctl.h>
#endif
#ifdef HAVE_SYS_UIO_H
#include <sys/uio.h>
#endif
#ifdef HAVE_POLL_H
#include <poll.h>
#endif

#if defined IOV_MAX
#define MAXIOV IOV_MAX
#elif defined UIO_MAXIOV
#define MAXIOV UIO_MAXIOV
#else
#define MAXIOV 16
#endif

#if !defined(HAVE_SETLOCALE) || !defined(HAVE_NL_LANGINFO) || !defined(HAVE_LANGINFO_H)
#define PRIMITIVE_UTF8_CHECK 1
#else
#include <langinfo.h>
#endif

#ifdef VALGRIND
#  include <valgrind/memcheck.h>
#endif

#define DEF_HEIGHT 24
#define DEF_WIDTH 80

enum TTYState {
    unavailable,
    disabled,
    enabled
};

typedef struct {
#ifdef __WIN32__
    HANDLE ofd;
    HANDLE ifd;
    DWORD dwOriginalOutMode;
    DWORD dwOriginalInMode;
    DWORD dwOutMode;
    DWORD dwInMode;

#else
    int ofd;       /* stdout */
    int ifd;       /* stdin */
#endif
    ErlNifPid self;
    ErlNifPid reader;
    enum TTYState tty;       /* if the tty is initialized */
#ifdef HAVE_TERMCAP
    struct termios tty_smode;
    struct termios tty_rmode;
#endif
} TTYResource;

// #define HARD_DEBUG
#ifdef HARD_DEBUG
static FILE *logFile = NULL;

#define debug(fmt, ...) do { if (logFile) { erts_fprintf(logFile, fmt, __VA_ARGS__); fflush(logFile); } } while(0)
#else
#define debug(...) do { } while(0)
#endif

static ErlNifResourceType *tty_rt;

/* The NIFs: */
static ERL_NIF_TERM isatty_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM tty_create_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM tty_init_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM tty_is_open(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM setlocale_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM tty_select_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM tty_write_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM tty_encoding_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM tty_read_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM isprint_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM wcwidth_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM wcswidth_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM sizeof_wchar_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM tty_window_size_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM tty_setupterm_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM tty_tigetnum_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM tty_tigetflag_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM tty_tinfo_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM tty_tigetstr_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM tty_tputs_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);

static ErlNifFunc nif_funcs[] = {
    {"isatty", 1, isatty_nif},
    {"tty_create", 1, tty_create_nif},
    {"tty_init", 2, tty_init_nif},
    {"setlocale", 1, setlocale_nif},
    {"tty_is_open", 2, tty_is_open},
    {"tty_select", 2, tty_select_nif},
    {"tty_window_size", 1, tty_window_size_nif},
    {"write_nif", 2, tty_write_nif, ERL_NIF_DIRTY_JOB_IO_BOUND},
    {"tty_encoding", 1, tty_encoding_nif},
    {"read_nif", 3, tty_read_nif, ERL_NIF_DIRTY_JOB_IO_BOUND},
    {"isprint", 1, isprint_nif},
    {"wcwidth", 1, wcwidth_nif},
    {"wcswidth", 1, wcswidth_nif},
    {"sizeof_wchar", 0, sizeof_wchar_nif},
    {"setupterm_nif", 0, tty_setupterm_nif},
    {"tigetnum_nif", 1, tty_tigetnum_nif},
    {"tigetflag_nif", 1, tty_tigetflag_nif},
    {"tinfo_nif", 0, tty_tinfo_nif},
    {"tigetstr_nif", 1, tty_tigetstr_nif},
    {"tputs_nif", 2, tty_tputs_nif}
};

/* NIF interface declarations */
static int load(ErlNifEnv* env, void** priv_data, ERL_NIF_TERM load_info);
static int upgrade(ErlNifEnv* env, void** priv_data, void** old_priv_data, ERL_NIF_TERM load_info);
static void unload(ErlNifEnv* env, void* priv_data);

ERL_NIF_INIT(prim_tty, nif_funcs, load, NULL, upgrade, unload)

#define ATOMS                                   \
    ATOM_DECL(canon);                           \
    ATOM_DECL(echo);                            \
    ATOM_DECL(ebadf);                           \
    ATOM_DECL(undefined);                       \
    ATOM_DECL(error);                           \
    ATOM_DECL(true);                            \
    ATOM_DECL(stdout);                          \
    ATOM_DECL(ok);                              \
    ATOM_DECL(input);                           \
    ATOM_DECL(false);                           \
    ATOM_DECL(stdin);                           \
    ATOM_DECL(stdout);                          \
    ATOM_DECL(stderr);                          \
    ATOM_DECL(select);                          \
    ATOM_DECL(raw);                          \
    ATOM_DECL(sig);


#define ATOM_DECL(A) static ERL_NIF_TERM atom_##A
ATOMS
#undef ATOM_DECL

static ERL_NIF_TERM make_error(ErlNifEnv *env, ERL_NIF_TERM reason) {
    return enif_make_tuple2(env, atom_error, reason);
}

static ERL_NIF_TERM make_enotsup(ErlNifEnv *env) {
    return make_error(env, enif_make_atom(env, "enotsup"));
}

static ERL_NIF_TERM make_errno(ErlNifEnv *env) {
#ifdef __WIN32__
    return enif_make_atom(env, last_error());
#else
    return enif_make_atom(env, erl_errno_id(errno));
#endif
}

static ERL_NIF_TERM make_errno_error(ErlNifEnv *env, const char *function) {
    return make_error(
        env, enif_make_tuple2(
            env, enif_make_atom(env, function), make_errno(env)));
}

static int tty_get_fd(ErlNifEnv *env, ERL_NIF_TERM atom, int *fd) {
    if (enif_is_identical(atom, atom_stdout)) {
        *fd = fileno(stdout);
    } else if (enif_is_identical(atom, atom_stdin)) {
        *fd =  fileno(stdin);
    } else if (enif_is_identical(atom, atom_stderr)) {
        *fd =  fileno(stderr);
    } else {
        return 0;
    }
    return 1;
}

#ifdef __WIN32__
static HANDLE tty_get_handle(ErlNifEnv *env, ERL_NIF_TERM atom) {
    HANDLE handle = INVALID_HANDLE_VALUE;
    int fd;
    if (tty_get_fd(env, atom, &fd)) {
    
        switch (fd) {
            case 0: handle = GetStdHandle(STD_INPUT_HANDLE); break;
            case 1: handle = GetStdHandle(STD_OUTPUT_HANDLE); break;
            case 2: handle = GetStdHandle(STD_ERROR_HANDLE); break;
        }
    }
    return handle;
}
#endif

static ERL_NIF_TERM isatty_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {
#ifdef __WIN32__
    HANDLE handle = tty_get_handle(env, argv[0]);

    if (handle == INVALID_HANDLE_VALUE)
        return atom_ebadf;
    
    switch (GetFileType(handle)) {
        case FILE_TYPE_CHAR: return atom_true;
        case FILE_TYPE_PIPE:
        case FILE_TYPE_DISK: return atom_false;
        default: return atom_ebadf;
    }
#else
    int fd;
    if (tty_get_fd(env, argv[0], &fd)) {
        if (isatty(fd)) {
            return atom_true;
        } else if (errno == EINVAL || errno == ENOTTY) {
            return atom_false;
        }
        else {
            return atom_ebadf;
        }
    }
#endif

    return enif_make_badarg(env);
}

static ERL_NIF_TERM tty_encoding_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {
#ifdef __WIN32__
    TTYResource *tty;
    if (!enif_get_resource(env, argv[0], tty_rt, (void **)&tty))
        return enif_make_badarg(env);
    if (GetFileType(tty->ifd) == FILE_TYPE_CHAR)
        return enif_make_tuple2(env, enif_make_atom(env, "utf16"),
                                enif_make_atom(env, "little"));
#endif
    return enif_make_atom(env, "utf8");
}


static ERL_NIF_TERM isprint_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {
    int i;
    if (enif_get_int(env, argv[0], &i)) {
        ASSERT(i >= 0 && i < 256);
        return isprint((char)i) ? atom_true : atom_false;
    }
    return enif_make_badarg(env);
}

static ERL_NIF_TERM wcwidth_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {
    int i;
    if (enif_get_int(env, argv[0], &i)) {
#ifndef __WIN32__
        int width;
        ASSERT(i > 0 && i < (1l << 21));
        width = wcwidth((wchar_t)i);
        if (width == -1) {
            return make_error(env, enif_make_atom(env, "not_printable"));
        }
        return enif_make_int(env, width);
#else
        return make_enotsup(env);
#endif
    }
    return enif_make_badarg(env);
}

static ERL_NIF_TERM wcswidth_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {
    ErlNifBinary bin;
    if (enif_inspect_iolist_as_binary(env, argv[0], &bin)) {
        wchar_t *chars = (wchar_t*)bin.data;
        int width;
#ifdef DEBUG
        for (int i = 0; i < bin.size / sizeof(wchar_t); i++) {
            ASSERT(chars[i] >= 0 && chars[i] < (1l << 21));
        }
#endif
#ifndef __WIN32__
        width = wcswidth(chars, bin.size / sizeof(wchar_t));
#else
        width = bin.size / sizeof(wchar_t);
#endif
        if (width == -1) {
            return make_error(env, enif_make_atom(env, "not_printable"));
        }
        return enif_make_tuple2(env, atom_ok, enif_make_int(env, width));
    }
    return enif_make_badarg(env);
}

static ERL_NIF_TERM sizeof_wchar_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {
    return enif_make_int(env, sizeof(wchar_t));
}

static ERL_NIF_TERM tty_write_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {
    ERL_NIF_TERM head = argv[1], tail;
    ErlNifIOQueue *q = NULL;
    ErlNifIOVec vec, *iovec = &vec;
    SysIOVec *iov;
    int iovcnt;
    TTYResource *tty;
    ssize_t res = 0;
    size_t size;
    if (!enif_get_resource(env, argv[0], tty_rt, (void **)&tty))
        return enif_make_badarg(env);

    while (!enif_is_identical(head, enif_make_list(env, 0))) {
        if (!enif_inspect_iovec(env, MAXIOV, head, &tail, &iovec))
            return enif_make_badarg(env);

        head = tail;

        iov = iovec->iov;
        size = iovec->size;
        iovcnt = iovec->iovcnt;

        do {
#ifndef __WIN32__
            do {
                res = writev(tty->ofd, iov, iovcnt);
            } while(res < 0 && (errno == EINTR || errno == EAGAIN));
#else
            res = 0;
            for (int i = 0; i < iovcnt; i++) {
                ssize_t written;
#ifdef HARD_DEBUG
		for (int y = 0; y < iov[i].iov_len; y++)
                    debug("Write %u\r\n",iov[i].iov_base[y]);
#endif
                BOOL r = WriteFile(tty->ofd, iov[i].iov_base,
                                   iov[i].iov_len, &written, NULL);
                if (!r) {
                    res = -1;
                    break;
                }
                res += written;
#ifdef DEBUG
                /* In debug we simulate a partial write in order to test
                   the code that handles it */
                break;
#endif
            }
#endif
            if (res < 0) {
                if (q) enif_ioq_destroy(q);
                return make_error(env, make_errno(env));
            }
            if (res != size) {
                if (!q) {
                    q = enif_ioq_create(ERL_NIF_IOQ_NORMAL);
                    enif_ioq_enqv(q, iovec, 0);
                }
            }

            if (q) {
                enif_ioq_deq(q, res, &size);
                if (size == 0) {
                    enif_ioq_destroy(q);
                    q = NULL;
                } else {
                    iov = enif_ioq_peek(q, &iovcnt);
                }
            }
        } while(q);

    };
    return atom_ok;
}

static ERL_NIF_TERM tty_read_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {
    TTYResource *tty;
    ErlNifBinary bin;
    ERL_NIF_TERM res_term;
    Uint64 n;
    ssize_t res = 0;
#ifdef __WIN32__
    HANDLE select_event;
#else
    int select_event;
#endif

    ASSERT(argc == 3);

    if (!enif_get_resource(env, argv[0], tty_rt, (void **)&tty))
        return enif_make_badarg(env);

    if (!enif_get_uint64(env, argv[2], &n))
        return enif_make_badarg(env);

    n = n > 1024 ? 1024 : n;

    select_event = tty->ifd;

    debug("tty_read_nif(%T, %T, %T)\r\n",argv[0],argv[1],argv[2]);

#ifdef __WIN32__
    /**
     * We have three different read scenarios we need to deal with
     * using different approaches.
     *
     * ### New Shell / Raw NoShell
     *
     * Here characters need to be delivered as they are typed and we
     * also need to handle terminal resize events. So we use ReadConsoleInputW
     * to read.
     *
     * ### Input is a terminal, but there is noshell, or old shell
     *
     * Here we should operate in "line mode", that is characters should only
     * be delivered when the user hits enter. Here we used to use OVERLAPPED ReadFile,
     * but that caused unicode to not work, so instead we use ReadFile. 
     * 
     * This call will block a single dirty io schedulers until the user hits Enter.
     *
     * ### Input is an anonymous pipe
     *
     * Since ReadConsoleInputW and OVERLAPPED ReadFile do not work on pipes
     * we use blocking ReadFile calls to read from pipes. On pipes the ReadFile
     * call will not block until a full line is complete, so this is safe to do.
     *
     **/
    if (GetFileType(tty->ifd) == FILE_TYPE_CHAR && tty->tty == enabled) {
        /* Input is a terminal and we are in "new shell"/"raw" mode */

        ssize_t inputs_read, num_characters = 0;
        wchar_t *characters = NULL;
        INPUT_RECORD inputs[128];

        n = MIN(n, sizeof(inputs) / sizeof(inputs[0]));

        ASSERT(tty->tty == enabled);

        if (!ReadConsoleInputW(tty->ifd, inputs, n, &inputs_read)) {
            return make_errno_error(env, "ReadConsoleInput");
        }

        /**
         * Reading keyevents using ReadConsoleInput is a bit fragile as
         * different consoles and different input modes cause events to
         * be triggered in different ways. I've so far identified four
         * different input methods that work slightly differently and
         * two classes of consoles that also work slightly differently.
         *
         * The input methods are:
         *   - Normal key presses
         *   - Microsoft IME
         *   - Pasting into console
         *   - Using Alt+ modifiers
         *
         * ### Normal key presses
         *
         * When typing normally both key down and up events are sent with
         * the typed character. If typing a Unicode character (for instance if
         * you are using a keyboard with Cyrillic layout), that character also
         * is sent as both key up and key down. This behavior is the same on all
         * consoles.
         *
         * ### Microsoft IME
         *
         * When typing Japanese, Chinese and many other languages it is common to
         * use a "Input Method Editor". Basically what it does is that if you type
         * "sushi" using the Japanese IME it convert that to "すし". All characters
         * typed using IME end up as only keydown events on cmd.exe and powershell,
         * while in Windows Terminal and Alacritty both keydown and keyup events
         * are sent.
         *
         * ### Pasting into console
         *
         * When text pasting into the console, any ascii text pasted ends up as both
         * keydown and keyup events. Any non-ascii text pasted seem to be sent using
         * a keydown event with UnicodeChar set to 0 and then immediately followed by a
         * keyup event with the non-ascii text.
         *
         * ### Using Alt+ modifiers
         *
         * A very old way of inputting Unicode characters on Windows is to press
         * the left alt key and then some numbers on the number pad. For instance
         * you can type Alt+1 to write a ☺. When doing this first a keydown
         * with 0 is sent and then some events later a keyup with the character
         * is sent. This behavior seems to only work on cmd.exe and powershell.
         *
         *
         * So to summarize:
         *  - Normal presses -- Always keydown and keyup events
         *  - IME -- Always keydown, sometimes keyup
         *  - Pasting -- Always keydown=0 directly followed by keyup=value
         *  - Alt+ -- Sometimes keydown=0 followed eventually by keyup=value
         *
         * So in order to read characters we should always read the keydown event,
         * except when it is 0, then we should read the adjacent keyup event.
         * This covers all modes and consoles except Alt+. If we want Alt+ to work
         * we probably have to use PeekConsoleInput to make sure the correct events
         * are available and inspect the state of the key event somehow.
         **/

        for (int i = 0; i < inputs_read; i++) {
            if (inputs[i].EventType == KEY_EVENT) {
                if (inputs[i].Event.KeyEvent.bKeyDown) {
                    if (inputs[i].Event.KeyEvent.uChar.UnicodeChar != 0) {
                        num_characters++;
                    } else if (i + 1 < inputs_read && !inputs[i+1].Event.KeyEvent.bKeyDown) {
                        num_characters++;
                    }
                }
            }
        }
        enif_alloc_binary(num_characters * sizeof(wchar_t), &bin);
        characters = (wchar_t*)bin.data;
        for (int i = 0; i < inputs_read; i++) {
            switch (inputs[i].EventType)
            {
            case KEY_EVENT:
                if (inputs[i].Event.KeyEvent.bKeyDown) {
                    if (inputs[i].Event.KeyEvent.uChar.UnicodeChar != 0) {
                        debug("Read %u\r\n",inputs[i].Event.KeyEvent.uChar.UnicodeChar);
                        characters[res++] = inputs[i].Event.KeyEvent.uChar.UnicodeChar;
                    } else if (i + 1 < inputs_read && !inputs[i+1].Event.KeyEvent.bKeyDown) {
                        debug("Read %u\r\n",inputs[i+1].Event.KeyEvent.uChar.UnicodeChar);
                        characters[res++] = inputs[i+1].Event.KeyEvent.uChar.UnicodeChar;
                    }
                }
                break;
            case WINDOW_BUFFER_SIZE_EVENT:
                enif_send(env, &tty->self, NULL,
                    enif_make_tuple2(env, argv[1],
                        enif_make_tuple2(env,
                            enif_make_atom(env, "signal"),
                            enif_make_atom(env, "resize"))));
                break;
            case MOUSE_EVENT:
                /* We don't do anything with the mouse event */
                break;
            case MENU_EVENT:
            case FOCUS_EVENT:
                /* Should be ignored according to
                    https://docs.microsoft.com/en-us/windows/console/input-record-str */
                break;
            default:
                fprintf(stderr,"Unknown event: %d\r\n", inputs[i].EventType);
                break;
            }
        }
        res *= sizeof(wchar_t);
    } else {
        /* Input is not a terminal or we are in "cooked" mode */
        DWORD bytesTransferred;
        BOOL readRes;
        const char *errorFunction;
        if (GetFileType(tty->ifd) == FILE_TYPE_CHAR) {
            /* This ReadConsoleW call may hang until Enter is pressed.
            * This will block one dirty io schedulers, but that should be ok as it will
            * only happen if the application wants to read data, i.e. it is reasonable to
            * expect and enter to be hit "soon".
            *
            * NOTE: I've tried various things to try to figure out if ReadFile/ReadConsole
            * will block or not, but one of the crazy thing with ReadFile/ReadConsole is
            * that you need to call it before the characters on the terminal are echoed,
            * so we need this call to be blocking. What we could do is move the read to another
            * thread so that we don't consume a dirty io scheduler, but I've opted to keep
            * it simple and not do that.
            */
            enif_alloc_binary(n * sizeof(wchar_t), &bin);
            readRes = ReadConsoleW(tty->ifd, bin.data, n, &bytesTransferred, NULL);
            bytesTransferred *= sizeof(wchar_t);
            errorFunction = "ReadConsoleW";
        }
        else {
            enif_alloc_binary(n, &bin);
            readRes = ReadFile(tty->ifd, bin.data, bin.size, &bytesTransferred, NULL);
            errorFunction = "ReadFile";
        }
        if (readRes) {
            res = bytesTransferred;
            if (res == 0) {
                enif_release_binary(&bin);
                return make_error(env, enif_make_atom(env, "closed"));
            }
        } else {
            DWORD error = GetLastError();
            enif_release_binary(&bin);
            if (error == ERROR_BROKEN_PIPE)
                return make_error(env, enif_make_atom(env, "closed"));
            return make_errno_error(env, errorFunction);
        }
    }
#else
    enif_alloc_binary(n, &bin);
    res = read(tty->ifd, bin.data, bin.size);
    if (res < 0) {
        if (errno != EAGAIN && errno != EINTR) {
            enif_release_binary(&bin);
            return make_errno_error(env, "read");
        }
        res = 0;
    } else if (res == 0) {
        enif_release_binary(&bin);
        return make_error(env, enif_make_atom(env, "closed"));
    }
#endif
    debug("select on %d\r\n",select_event);
    enif_select(env, select_event, ERL_NIF_SELECT_READ, tty, NULL, argv[1]);
    if (res == bin.size) {
	res_term = enif_make_binary(env, &bin);
    } else if (res < bin.size / 2) {
        unsigned char *buff = enif_make_new_binary(env, res, &res_term);
        if (res > 0) {
            memcpy(buff, bin.data, res);
        }
        enif_release_binary(&bin);
    } else {
        enif_realloc_binary(&bin, res);
        res_term = enif_make_binary(env, &bin);
    }

    return enif_make_tuple2(env, atom_ok, res_term);
}

/* Poll if stdin/stdout/stderr are still open. */
static ERL_NIF_TERM tty_is_open(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {
    TTYResource *tty;
#ifdef __WIN32__
    HANDLE handle;
#else
    int fd;
#endif

    if (!enif_get_resource(env, argv[0], tty_rt, (void **)&tty))
        return enif_make_badarg(env);

#ifdef __WIN32__

    handle = tty_get_handle(env, argv[1]);

    if (handle != INVALID_HANDLE_VALUE) {
        DWORD bytesAvailable = 0;

        switch (GetFileType(handle))  {
            case FILE_TYPE_CHAR: {
                DWORD eventsAvailable;
                if (!GetNumberOfConsoleInputEvents(handle, &eventsAvailable)) {
                    return atom_false;
                }
                return atom_true;
            }
            case FILE_TYPE_DISK: {
                return atom_true;
            }
            default: {
                DWORD bytesAvailable = 0;
                // Check the state of the pipe
                if (!PeekNamedPipe(handle, NULL, 0, NULL, &bytesAvailable, NULL)) {
                    DWORD err = GetLastError();

                    // If the error is ERROR_BROKEN_PIPE, it means stdin has been closed
                    if (err == ERROR_BROKEN_PIPE) {
                        return atom_false;
                    }
                    else {
                        return make_errno_error(env, "PeekNamedPipe");
                    }
                }
                return atom_true;
            }
        }
    }
#else
    if (tty_get_fd(env, argv[1], &fd)) {
        struct pollfd fds[1];
        int ret;
        
        fds[0].fd = fd;
        fds[0].events = POLLHUP;
        fds[0].revents = 0;
        ret = poll(fds, 1, 0);

        if (ret < 0) {
            return make_errno_error(env, __FUNCTION__);
        } else if (ret == 0) {
            return atom_true;
        } else if (ret == 1 && fds[0].revents & POLLHUP) {
            return atom_false;
        }
    }
#endif
    return enif_make_badarg(env);
}

static ERL_NIF_TERM setlocale_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {
#ifdef __WIN32__
    TTYResource *tty;

    if (!enif_get_resource(env, argv[0], tty_rt, (void **)&tty))
        return enif_make_badarg(env);

    if (tty->dwOutMode)
    {
        if (!SetConsoleOutputCP(CP_UTF8)) {
            return make_errno_error(env, "SetConsoleOutputCP");
        }
    }
    return atom_true;
#elif defined(PRIMITIVE_UTF8_CHECK)
    setlocale(LC_CTYPE, "");  /* Set international environment, 
				 ignore result */
    return enif_make_atom(env, "primitive");
#else
    char *l = setlocale(LC_CTYPE, "");  /* Set international environment */
    if (l != NULL) {
	if (strcmp(nl_langinfo(CODESET), "UTF-8") == 0)
            return atom_true;
    }
    return atom_false;
#endif
}
#ifdef HAVE_TERMCAP
static TERMINAL *saved_term = NULL;
#endif
static ERL_NIF_TERM tty_setupterm_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {
#ifdef HAVE_TERMCAP
    int errret;
    if (setupterm(NULL, -1, &errret) < 0) {
        return make_errno_error(env, "setupterm");
    }
    if (saved_term) {
        del_curterm(saved_term);
    }
    saved_term = cur_term;
    return atom_ok;
#else
    return make_enotsup(env);
#endif
}

#ifdef HAVE_TERMCAP
static ERL_NIF_TERM tty_tinfo_make_map(ErlNifEnv* env,
                                       NCURSES_CONST char * const* names,
                                       NCURSES_CONST char * const* codes,
                                       NCURSES_CONST char * const* fnames) {
    ERL_NIF_TERM res = enif_make_list(env, 0);
    ERL_NIF_TERM ks[3] = {
        enif_make_atom(env, "name"),
        enif_make_atom(env, "code"),
        enif_make_atom(env, "full_name")
    };
    for (int i = 0; names[i] && codes[i] && fnames[i]; i++) {
        ERL_NIF_TERM map;
        ERL_NIF_TERM vs[3] = {
            enif_make_string(env, names[i], ERL_NIF_LATIN1),
            enif_make_string(env, codes[i], ERL_NIF_LATIN1),
            enif_make_string(env, fnames[i], ERL_NIF_LATIN1)
        };
         enif_make_map_from_arrays(env, ks, vs, 3, &map);
        res = enif_make_list_cell(env, map, res);
    }
    return res;
}
#endif

static ERL_NIF_TERM tty_tinfo_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {
#ifdef HAVE_TERMCAP
    ERL_NIF_TERM ks[3] = {
        enif_make_atom(env, "bool"),
        enif_make_atom(env, "num"),
        enif_make_atom(env, "str")
    };

    ERL_NIF_TERM vs[3] = {
        tty_tinfo_make_map(env, (NCURSES_CONST char * const*)boolnames, (NCURSES_CONST char * const*)boolcodes, (NCURSES_CONST char * const*)boolfnames),
        tty_tinfo_make_map(env, (NCURSES_CONST char * const*)numnames, (NCURSES_CONST char * const*)numcodes, (NCURSES_CONST char * const*)numfnames),
        tty_tinfo_make_map(env, (NCURSES_CONST char * const*)strnames, (NCURSES_CONST char * const*)strcodes, (NCURSES_CONST char * const*)strfnames)
    };
    ERL_NIF_TERM res;
    
    enif_make_map_from_arrays(env, ks, vs, 3, &res);

    return res;
#else
    return make_enotsup(env);
#endif
}

static ERL_NIF_TERM tty_tigetnum_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {
#ifdef HAVE_TERMCAP
    ErlNifBinary CAP;
    if (!enif_inspect_iolist_as_binary(env, argv[0], &CAP))
        return enif_make_badarg(env);
    return enif_make_int(env, tgetnum((char*)CAP.data));
#else
    return make_enotsup(env);
#endif
}

static ERL_NIF_TERM tty_tigetflag_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {
#ifdef HAVE_TERMCAP
    ErlNifBinary CAP;
    if (!enif_inspect_iolist_as_binary(env, argv[0], &CAP))
        return enif_make_badarg(env);
    if (tgetflag((char*)CAP.data))
        return atom_true;
    return atom_false;
#else
    return make_enotsup(env);
#endif
}

static ERL_NIF_TERM tty_tigetstr_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {
#ifdef HAVE_TERMCAP
    ErlNifBinary CAP, ret;
    char *str;
    if (!enif_inspect_iolist_as_binary(env, argv[0], &CAP))
        return enif_make_badarg(env);
    str = tigetstr((char*)CAP.data);
    if (!str) return atom_false; /* Not supported by terminal */
    if (str == (char*)-1) return enif_make_badarg(env); /* Invalid capability */
    enif_alloc_binary(strlen(str), &ret);
    memcpy(ret.data, str, strlen(str));
    return enif_make_tuple2(
        env, atom_ok, enif_make_binary(env, &ret));
#else
    return make_enotsup(env);
#endif
}

static int library_refc = 0;
#ifdef HAVE_TERMCAP
static ErlNifMutex *tputs_mutex;
static int tputs_buffer_index;
static int tputs_buffer_size;
#ifdef DEBUG
static unsigned char static_tputs_buffer[2];
#else
static unsigned char static_tputs_buffer[1024];
#endif
static unsigned char *tputs_buffer;

#if defined(__sun) && defined(__SVR4) /* Solaris */
static int tty_puts_putc(char c) {
#else
static int tty_puts_putc(int c) {
#endif

    /* If we have a terminal that does a lot of padding, then it might be
       that a lot of text is generated here. Those types of terminals are
       ancient and most likely not in use anymore, but just to be safe we
       handle it by dynamically resizing the buffer. */
    if (tputs_buffer_index == tputs_buffer_size) {
        if (tputs_buffer == static_tputs_buffer) {
            tputs_buffer = enif_alloc(tputs_buffer_size * 2);
            memcpy(tputs_buffer, static_tputs_buffer, tputs_buffer_size);
            tputs_buffer_size *= 2;
        } else {
            tputs_buffer = enif_realloc(tputs_buffer, tputs_buffer_size * 2);
            tputs_buffer_size *= 2;
        }
    }

    tputs_buffer[tputs_buffer_index++] = (unsigned char)c;
    return 0;

}
#endif

static ERL_NIF_TERM tty_tputs_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {
#ifdef HAVE_TERMCAP
    ErlNifBinary cap;
    ERL_NIF_TERM ret;
    char *ent;
    unsigned char *buff;
    long params[9] = { 0 };
    int slot = 0;

    if (!enif_inspect_iolist_as_binary(env, argv[0], &cap))
        return enif_make_badarg(env);

    {
        ERL_NIF_TERM head, tail = argv[1];
        while(enif_get_list_cell(env, tail, &head, &tail)) {
            if (!enif_get_long(env, head, params + slot)) {
                return enif_make_badarg(env);
            }
            slot++;
        }
        if (!enif_is_empty_list(env, tail)) {
            enif_make_badarg(env);
        }
    }

    /* Neither tparm nor tputs are thread safe.. */
    enif_mutex_lock(tputs_mutex);

    /* If the capability has arguments, we call tparm */
    if (slot) {
        /* The https://linux.die.net/man/3/tparm specifies that although tparm uses
           a vararg prototype on Linux, to be portable we should always call it with
           9 arguments as some implementation have a static prototype.
        */
        ent = tparm((char*)cap.data, params[0], params[1], params[2], params[3],
                    params[4], params[5], params[6], params[7], params[8]);
            
        if (!ent) {
            enif_mutex_unlock(tputs_mutex);
            return make_errno_error(env, "tparm");
        }
    } else {
        ent = (char*)cap.data;
    }

    tputs_buffer_index = 0;
    tputs_buffer_size = sizeof(static_tputs_buffer);
    tputs_buffer = static_tputs_buffer;
    (void)tputs(ent, 1, tty_puts_putc); /* tputs only fails if ent is null,
                                           which is cannot be. */

    buff = enif_make_new_binary(env, tputs_buffer_index, &ret);
    memcpy(buff, tputs_buffer, tputs_buffer_index);

    if (tputs_buffer != static_tputs_buffer) {
        enif_free(tputs_buffer);
    }

    enif_mutex_unlock(tputs_mutex);

    return enif_make_tuple2(env, atom_ok, ret);
#else
    return make_enotsup(env);
#endif
}

static ERL_NIF_TERM tty_create_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {

    TTYResource *tty = enif_alloc_resource(tty_rt, sizeof(TTYResource));
    ERL_NIF_TERM tty_term;
    memset(tty, 0, sizeof(*tty));

#ifdef HARD_DEBUG
    logFile = fopen("tty.log","w+");
#endif

    tty->tty = unavailable;

#ifndef __WIN32__
    tty->ifd = 0;
    tty->ofd = 0;
    if (!tty_get_fd(env, argv[0], &tty->ofd) || tty->ofd == 0)
        return enif_make_badarg(env);

#ifdef HAVE_TERMCAP
    if (tcgetattr(tty->ofd, &tty->tty_rmode) >= 0) {
        tty->tty = disabled;
    }
    tty->tty_smode = tty->tty_rmode;
#endif

#else

    /* argv[0] can only be stdout or stderr */
    if (enif_is_identical(argv[0], atom_stdin))
        return enif_make_badarg(env);

    /* If argv[0] is stdout we also enable stdin */
    if (enif_is_identical(argv[0], atom_stdout)) {
        tty->ifd = GetStdHandle(STD_INPUT_HANDLE);
        /* if stdin is an invalid handle, we create a nul device for it */
        if (tty->ifd == INVALID_HANDLE_VALUE || tty->ifd == NULL) {
            tty->ifd = CreateFile("nul", GENERIC_READ, 0,
                                  NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
        }
    } else {
        tty->ifd = INVALID_HANDLE_VALUE;
    }

    tty->ofd = tty_get_handle(env, argv[0]);
    /* if ofd is an invalid handle, we create a nul device for it */
    if (tty->ofd == INVALID_HANDLE_VALUE || tty->ofd == NULL) {
        tty->ofd = CreateFile("nul", GENERIC_WRITE, 0,
                              NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
    }

    if (GetConsoleMode(tty->ofd, &tty->dwOriginalOutMode))
    {
        tty->dwOutMode = ENABLE_VIRTUAL_TERMINAL_PROCESSING | tty->dwOriginalOutMode;
        if (!SetConsoleMode(tty->ofd, tty->dwOutMode)) {
            /* Failed to set any VT mode, can't do anything here. */
            return make_errno_error(env, "SetConsoleModeOut");
        }
        tty->tty = disabled;
    }

    if (GetConsoleMode(tty->ifd, &tty->dwOriginalInMode))
    {
        tty->dwInMode = ENABLE_VIRTUAL_TERMINAL_INPUT | tty->dwOriginalInMode;
        if (!SetConsoleMode(tty->ifd, tty->dwInMode)) {
            /* Failed to set any VT mode, can't do anything here. */
            return make_errno_error(env, "SetConsoleModeIn");
        }
    } else {
        /* If we cannot get the console mode, mark the TTY as unavailable
           This can happen when the input handle is a pipe, but the output
           handle is a console.
        */
        tty->tty = unavailable;
    }
    
#endif

    tty_term = enif_make_resource(env, tty);
    enif_release_resource(tty);

    enif_set_pid_undefined(&tty->self);
    enif_set_pid_undefined(&tty->reader);

    return enif_make_tuple2(env, atom_ok, tty_term);
}

static ERL_NIF_TERM tty_init_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {

    ERL_NIF_TERM input, signals;
    TTYResource *tty;

    debug("tty_init_nif(%T,%T)\r\n", argv[0], argv[1]);

    if (argc != 2 || !enif_is_map(env, argv[1])) {
        return enif_make_badarg(env);
    }

    if (!enif_get_resource(env, argv[0], tty_rt, (void **)&tty))
        return enif_make_badarg(env);

    if (!enif_get_map_value(env, argv[1], enif_make_atom(env, "input"), &input))
        return enif_make_badarg(env);

    /* Whether signal and flow-control handling should stay enabled in
       raw mode. Defaults to true to preserve the shell's ctrl+c break
       behavior. When false, ISIG, IEXTEN and IXON are disabled so that
       control bytes such as ctrl+o, ctrl+c and ctrl+s/ctrl+q reach the
       application. */
    if (!enif_get_map_value(env, argv[1], enif_make_atom(env, "signals"), &signals))
        signals = atom_true;

    if (tty->tty == unavailable) {
        if (enif_is_identical(input, atom_raw))
            return make_enotsup(env);
        return atom_ok;
    }

#if defined(HAVE_TERMCAP) || defined(__WIN32__)

    tty->tty = enif_is_identical(input, atom_raw) ? enabled : disabled;

#ifndef __WIN32__

    if (tty->tty == enabled || sys_memcmp(&tty->tty_smode, &tty->tty_rmode, sizeof(tty->tty_rmode)) != 0) {

        /* Restore the original mode, that is canonical echo mode */
        tty->tty_smode = tty->tty_rmode;

        if (tty->tty == enabled) {

            /* Default characteristics for all usage including termcap output. */
            tty->tty_smode.c_iflag &= ~ISTRIP;

            /* erts_fprintf(stderr,"canon %T\r\n", canon); */
            /* Turn canonical (line mode) off. */
            tty->tty_smode.c_iflag &= ~ICRNL;
            tty->tty_smode.c_lflag &= ~ICANON;
            tty->tty_smode.c_oflag &= ~OPOST;

            tty->tty_smode.c_cc[VMIN] = 1;
            tty->tty_smode.c_cc[VTIME] = 0;
    #ifdef VDSUSP
            tty->tty_smode.c_cc[VDSUSP] = 0;
    #endif

            /* Turn echo off. */
            /* erts_fprintf(stderr,"echo %T\r\n", echo); */
            tty->tty_smode.c_lflag &= ~ECHO;

            if (enif_is_identical(signals, atom_false)) {
                /* Also disable signal and flow-control handling so that
                   control bytes are passed through to the application.
                   This restores the sig => false behavior that the
                   prim_tty API had before the OTP 28 shell improvements. */
                tty->tty_smode.c_iflag &= ~(BRKINT|IGNPAR|IXON|IXANY);
                tty->tty_smode.c_lflag &= ~(ISIG|IEXTEN);
            }

        }

        if (tcsetattr(tty->ofd, TCSANOW, &tty->tty_smode) < 0) {
            return make_errno_error(env, "tcsetattr");
        }
    }

#else
    DWORD dwOutMode = tty->dwOutMode;
    DWORD dwInMode = tty->dwInMode;
    
    debug("origOutMode: %x origInMode: %x\r\n", 
          tty->dwOriginalOutMode, tty->dwOriginalInMode);

    if (tty->tty == enabled) {
        dwOutMode  |= DISABLE_NEWLINE_AUTO_RETURN;
        dwInMode &= ~(ENABLE_ECHO_INPUT | ENABLE_LINE_INPUT);
        if (enif_is_identical(signals, atom_false)) {
            /* Pass ctrl+c through to the application instead of
               generating a console event for it. */
            dwInMode &= ~ENABLE_PROCESSED_INPUT;
        }
    }

    if (tty->ifd != INVALID_HANDLE_VALUE && !SetConsoleMode(tty->ifd, dwInMode))
    {
        /* Failed to set disable echo or line input mode */
        return make_errno_error(env, "SetConsoleModeInitIn");
    }

    
    if (!SetConsoleMode(tty->ofd, dwOutMode)) {
        /* If we cannot disable NEWLINE_AUTO_RETURN we continue anyway as things work */
        ;
    }

#endif /* __WIN32__ */

    enif_self(env, &tty->self);
    enif_monitor_process(env, tty, &tty->self, NULL);

    return atom_ok;
#else
    return make_enotsup(env);
#endif
}

static ERL_NIF_TERM tty_window_size_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {
    TTYResource *tty;
    int width = -1, height = -1;
    if (!enif_get_resource(env, argv[0], tty_rt, (void **)&tty))
        return enif_make_badarg(env);
    {
#ifdef TIOCGWINSZ
        struct winsize ws;
        if (ioctl(tty->ifd,TIOCGWINSZ,&ws) == 0) {
            if (ws.ws_col > 0)
                width = ws.ws_col;
            if (ws.ws_row > 0)
                height = ws.ws_row;
        } else if (ioctl(tty->ofd,TIOCGWINSZ,&ws) == 0) {
            if (ws.ws_col > 0)
                width = ws.ws_col;
            if (ws.ws_row > 0)
                height = ws.ws_row;
        }
#elif defined(__WIN32__)
        CONSOLE_SCREEN_BUFFER_INFOEX buffer_info;
        buffer_info.cbSize = sizeof(buffer_info);
        if (GetConsoleScreenBufferInfoEx(tty->ofd, &buffer_info)) {
            height = buffer_info.dwSize.Y;
            width = buffer_info.dwSize.X;
        } else {
            return make_errno_error(env,"GetConsoleScreenBufferInfoEx");
        }
#endif
    }
    if (width == -1 && height == -1) {
        return make_enotsup(env);
    }
    return enif_make_tuple2(
        env, atom_ok,
        enif_make_tuple2(
            env,
            enif_make_int(env, width),
            enif_make_int(env, height)
            ));
}

static ERL_NIF_TERM tty_select_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {
    TTYResource *tty;

#ifndef __WIN32__
    extern int using_oldshell; /* set this to let the rest of erts know */
#endif

    if (!enif_get_resource(env, argv[0], tty_rt, (void **)&tty))
        return enif_make_badarg(env);

#ifndef __WIN32__
    using_oldshell = 0;
#endif
    debug("Select on %d\r\n", tty->ifd);
    enif_select(env, tty->ifd, ERL_NIF_SELECT_READ, tty, NULL, argv[1]);

    enif_self(env, &tty->reader);
    enif_monitor_process(env, tty, &tty->reader, NULL);

    return atom_ok;
}

static void tty_monitor_down(ErlNifEnv* caller_env, void* obj, ErlNifPid* pid, ErlNifMonitor* mon) {
    TTYResource *tty = obj;
#ifdef HAVE_TERMCAP
    if (enif_compare_pids(pid, &tty->self) == 0) {
        tcsetattr(tty->ifd, TCSANOW, &tty->tty_rmode);
    }
#endif
    if (enif_compare_pids(pid, &tty->reader) == 0) {
        enif_select(caller_env, tty->ifd, ERL_NIF_SELECT_STOP, tty, NULL, atom_undefined);
    }
}

static void tty_select_stop(ErlNifEnv* caller_env, void* obj, ErlNifEvent event, int is_direct_call) {
/* Only used to close the signal pipe on unix */
#ifndef __WIN32__
    if (event != 0)
        close(event);
#endif
}

static void init(ErlNifEnv* env, ErlNifResourceFlags rt_flags) {
    ErlNifResourceTypeInit rt = {
        NULL /* dtor */,
        tty_select_stop,
        tty_monitor_down};

    tty_rt = enif_open_resource_type_x(env, "tty", &rt, rt_flags, NULL);

    if (library_refc == 0) {
#ifdef HAVE_TERMCAP
        tputs_mutex = enif_mutex_create("tputs_muex");
#endif
#define ATOM_DECL(A) atom_##A = enif_make_atom(env, #A)
        ATOMS
#undef ATOM_DECL
    }
    ++library_refc;
}

static int load(ErlNifEnv* env, void** priv_data, ERL_NIF_TERM load_info)
{
    *priv_data = NULL;
    init(env, ERL_NIF_RT_CREATE);
    return 0;
}

static void unload(ErlNifEnv* env, void* priv_data)
{
    --library_refc;
#ifdef HAVE_TERMCAP
    if (library_refc == 0) {
        enif_mutex_destroy(tputs_mutex);
        tputs_mutex = NULL;

        if (saved_term) {
            del_curterm(saved_term);
            saved_term = NULL;
        }
    }
#endif
}

static int upgrade(ErlNifEnv* env, void** priv_data, void** old_priv_data,
                   ERL_NIF_TERM load_info)
{
    if (*old_priv_data != NULL) {
        return -1; /* Don't know how to do that */
    }
    if (*priv_data != NULL) {
        return -1; /* Don't know how to do that */
    }
    *priv_data = NULL;
    init(env, ERL_NIF_RT_TAKEOVER);
    return 0;
}