/* $OpenBSD: tty-keys.c,v 1.204 2026/04/03 08:23:10 nicm Exp $ */

/*
 * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
 * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>
#include <sys/time.h>

#include <netinet/in.h>

#include <ctype.h>
#include <limits.h>
#include <resolv.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>

#include "tmux.h"

/*
 * Handle keys input from the outside terminal. tty_default_*_keys[] are a base
 * table of supported keys which are looked up in terminfo(5) and translated
 * into a ternary tree.
 */

static void     tty_keys_add1(struct tty_key **, const char *, key_code);
static void     tty_keys_add(struct tty *, const char *, key_code);
static void     tty_keys_free1(struct tty_key *);
static struct tty_key *tty_keys_find1(struct tty_key *, const char *, size_t,
                    size_t *);
static struct tty_key *tty_keys_find(struct tty *, const char *, size_t,
                    size_t *);
static int      tty_keys_next1(struct tty *, const char *, size_t, key_code *,
                    size_t *, int);
static void     tty_keys_callback(int, short, void *);
static int      tty_keys_extended_key(struct tty *, const char *, size_t,
                    size_t *, key_code *);
static int      tty_keys_mouse(struct tty *, const char *, size_t, size_t *,
                    struct mouse_event *);
static int      tty_keys_clipboard(struct tty *, const char *, size_t,
                    size_t *);
static int      tty_keys_device_attributes(struct tty *, const char *, size_t,
                    size_t *);
static int      tty_keys_device_attributes2(struct tty *, const char *, size_t,
                    size_t *);
static int      tty_keys_extended_device_attributes(struct tty *, const char *,
                    size_t, size_t *);
static int      tty_keys_palette(struct tty *, const char *, size_t, size_t *);

/* A key tree entry. */
struct tty_key {
        char             ch;
        key_code         key;

        struct tty_key  *left;
        struct tty_key  *right;

        struct tty_key  *next;
};

/* Default raw keys. */
struct tty_default_key_raw {
        const char             *string;
        key_code                key;
};
static const struct tty_default_key_raw tty_default_raw_keys[] = {
        /* Application escape. */
        { "\033O[", '\033' },

        /*
         * Numeric keypad. Just use the vt100 escape sequences here and always
         * put the terminal into keypad_xmit mode. Translation of numbers
         * mode/applications mode is done in input-keys.c.
         */
        { "\033Oo", KEYC_KP_SLASH|KEYC_KEYPAD },
        { "\033Oj", KEYC_KP_STAR|KEYC_KEYPAD },
        { "\033Om", KEYC_KP_MINUS|KEYC_KEYPAD },
        { "\033Ow", KEYC_KP_SEVEN|KEYC_KEYPAD },
        { "\033Ox", KEYC_KP_EIGHT|KEYC_KEYPAD },
        { "\033Oy", KEYC_KP_NINE|KEYC_KEYPAD },
        { "\033Ok", KEYC_KP_PLUS|KEYC_KEYPAD },
        { "\033Ot", KEYC_KP_FOUR|KEYC_KEYPAD },
        { "\033Ou", KEYC_KP_FIVE|KEYC_KEYPAD },
        { "\033Ov", KEYC_KP_SIX|KEYC_KEYPAD },
        { "\033Oq", KEYC_KP_ONE|KEYC_KEYPAD },
        { "\033Or", KEYC_KP_TWO|KEYC_KEYPAD },
        { "\033Os", KEYC_KP_THREE|KEYC_KEYPAD },
        { "\033OM", KEYC_KP_ENTER|KEYC_KEYPAD },
        { "\033Op", KEYC_KP_ZERO|KEYC_KEYPAD },
        { "\033On", KEYC_KP_PERIOD|KEYC_KEYPAD },

        /* Arrow keys. */
        { "\033OA", KEYC_UP|KEYC_CURSOR },
        { "\033OB", KEYC_DOWN|KEYC_CURSOR },
        { "\033OC", KEYC_RIGHT|KEYC_CURSOR },
        { "\033OD", KEYC_LEFT|KEYC_CURSOR },

        { "\033[A", KEYC_UP|KEYC_CURSOR },
        { "\033[B", KEYC_DOWN|KEYC_CURSOR },
        { "\033[C", KEYC_RIGHT|KEYC_CURSOR },
        { "\033[D", KEYC_LEFT|KEYC_CURSOR },

        /*
         * Meta arrow keys. These do not get the IMPLIED_META flag so they
         * don't match the xterm-style meta keys in the output tree - Escape+Up
         * should stay as Escape+Up and not become M-Up.
         */
        { "\033\033OA", KEYC_UP|KEYC_CURSOR|KEYC_META },
        { "\033\033OB", KEYC_DOWN|KEYC_CURSOR|KEYC_META },
        { "\033\033OC", KEYC_RIGHT|KEYC_CURSOR|KEYC_META },
        { "\033\033OD", KEYC_LEFT|KEYC_CURSOR|KEYC_META },

        { "\033\033[A", KEYC_UP|KEYC_CURSOR|KEYC_META },
        { "\033\033[B", KEYC_DOWN|KEYC_CURSOR|KEYC_META },
        { "\033\033[C", KEYC_RIGHT|KEYC_CURSOR|KEYC_META },
        { "\033\033[D", KEYC_LEFT|KEYC_CURSOR|KEYC_META },

        /* Other xterm keys. */
        { "\033OH", KEYC_HOME },
        { "\033OF", KEYC_END },

        { "\033\033OH", KEYC_HOME|KEYC_META|KEYC_IMPLIED_META },
        { "\033\033OF", KEYC_END|KEYC_META|KEYC_IMPLIED_META },

        { "\033[H", KEYC_HOME },
        { "\033[F", KEYC_END },

        { "\033\033[H", KEYC_HOME|KEYC_META|KEYC_IMPLIED_META },
        { "\033\033[F", KEYC_END|KEYC_META|KEYC_IMPLIED_META },

        /* rxvt arrow keys. */
        { "\033Oa", KEYC_UP|KEYC_CTRL },
        { "\033Ob", KEYC_DOWN|KEYC_CTRL },
        { "\033Oc", KEYC_RIGHT|KEYC_CTRL },
        { "\033Od", KEYC_LEFT|KEYC_CTRL },

        { "\033[a", KEYC_UP|KEYC_SHIFT },
        { "\033[b", KEYC_DOWN|KEYC_SHIFT },
        { "\033[c", KEYC_RIGHT|KEYC_SHIFT },
        { "\033[d", KEYC_LEFT|KEYC_SHIFT },

        /* rxvt function keys. */
        { "\033[11~", KEYC_F1 },
        { "\033[12~", KEYC_F2 },
        { "\033[13~", KEYC_F3 },
        { "\033[14~", KEYC_F4 },
        { "\033[15~", KEYC_F5 },
        { "\033[17~", KEYC_F6 },
        { "\033[18~", KEYC_F7 },
        { "\033[19~", KEYC_F8 },
        { "\033[20~", KEYC_F9 },
        { "\033[21~", KEYC_F10 },

        { "\033[23~", KEYC_F1|KEYC_SHIFT },
        { "\033[24~", KEYC_F2|KEYC_SHIFT },
        { "\033[25~", KEYC_F3|KEYC_SHIFT },
        { "\033[26~", KEYC_F4|KEYC_SHIFT },
        { "\033[28~", KEYC_F5|KEYC_SHIFT },
        { "\033[29~", KEYC_F6|KEYC_SHIFT },
        { "\033[31~", KEYC_F7|KEYC_SHIFT },
        { "\033[32~", KEYC_F8|KEYC_SHIFT },
        { "\033[33~", KEYC_F9|KEYC_SHIFT },
        { "\033[34~", KEYC_F10|KEYC_SHIFT },
        { "\033[23$", KEYC_F11|KEYC_SHIFT },
        { "\033[24$", KEYC_F12|KEYC_SHIFT },

        { "\033[11^", KEYC_F1|KEYC_CTRL },
        { "\033[12^", KEYC_F2|KEYC_CTRL },
        { "\033[13^", KEYC_F3|KEYC_CTRL },
        { "\033[14^", KEYC_F4|KEYC_CTRL },
        { "\033[15^", KEYC_F5|KEYC_CTRL },
        { "\033[17^", KEYC_F6|KEYC_CTRL },
        { "\033[18^", KEYC_F7|KEYC_CTRL },
        { "\033[19^", KEYC_F8|KEYC_CTRL },
        { "\033[20^", KEYC_F9|KEYC_CTRL },
        { "\033[21^", KEYC_F10|KEYC_CTRL },
        { "\033[23^", KEYC_F11|KEYC_CTRL },
        { "\033[24^", KEYC_F12|KEYC_CTRL },

        { "\033[11@", KEYC_F1|KEYC_CTRL|KEYC_SHIFT },
        { "\033[12@", KEYC_F2|KEYC_CTRL|KEYC_SHIFT },
        { "\033[13@", KEYC_F3|KEYC_CTRL|KEYC_SHIFT },
        { "\033[14@", KEYC_F4|KEYC_CTRL|KEYC_SHIFT },
        { "\033[15@", KEYC_F5|KEYC_CTRL|KEYC_SHIFT },
        { "\033[17@", KEYC_F6|KEYC_CTRL|KEYC_SHIFT },
        { "\033[18@", KEYC_F7|KEYC_CTRL|KEYC_SHIFT },
        { "\033[19@", KEYC_F8|KEYC_CTRL|KEYC_SHIFT },
        { "\033[20@", KEYC_F9|KEYC_CTRL|KEYC_SHIFT },
        { "\033[21@", KEYC_F10|KEYC_CTRL|KEYC_SHIFT },
        { "\033[23@", KEYC_F11|KEYC_CTRL|KEYC_SHIFT },
        { "\033[24@", KEYC_F12|KEYC_CTRL|KEYC_SHIFT },

        /* Focus tracking. */
        { "\033[I", KEYC_FOCUS_IN },
        { "\033[O", KEYC_FOCUS_OUT },

        /* Paste keys. */
        { "\033[200~", KEYC_PASTE_START|KEYC_IMPLIED_META },
        { "\033[201~", KEYC_PASTE_END|KEYC_IMPLIED_META },

        /* Extended keys. */
        { "\033[1;5Z", '\011'|KEYC_CTRL|KEYC_SHIFT },

        /* Theme reporting. */
        { "\033[?997;1n", KEYC_REPORT_DARK_THEME },
        { "\033[?997;2n", KEYC_REPORT_LIGHT_THEME },
};

/* Default xterm keys. */
struct tty_default_key_xterm {
        const char      *template;
        key_code         key;
};
static const struct tty_default_key_xterm tty_default_xterm_keys[] = {
        { "\033[1;_P", KEYC_F1 },
        { "\033O1;_P", KEYC_F1 },
        { "\033O_P", KEYC_F1 },
        { "\033[1;_Q", KEYC_F2 },
        { "\033O1;_Q", KEYC_F2 },
        { "\033O_Q", KEYC_F2 },
        { "\033[1;_R", KEYC_F3 },
        { "\033O1;_R", KEYC_F3 },
        { "\033O_R", KEYC_F3 },
        { "\033[1;_S", KEYC_F4 },
        { "\033O1;_S", KEYC_F4 },
        { "\033O_S", KEYC_F4 },
        { "\033[15;_~", KEYC_F5 },
        { "\033[17;_~", KEYC_F6 },
        { "\033[18;_~", KEYC_F7 },
        { "\033[19;_~", KEYC_F8 },
        { "\033[20;_~", KEYC_F9 },
        { "\033[21;_~", KEYC_F10 },
        { "\033[23;_~", KEYC_F11 },
        { "\033[24;_~", KEYC_F12 },
        { "\033[1;_A", KEYC_UP },
        { "\033[1;_B", KEYC_DOWN },
        { "\033[1;_C", KEYC_RIGHT },
        { "\033[1;_D", KEYC_LEFT },
        { "\033[1;_H", KEYC_HOME },
        { "\033[1;_F", KEYC_END },
        { "\033[5;_~", KEYC_PPAGE },
        { "\033[6;_~", KEYC_NPAGE },
        { "\033[2;_~", KEYC_IC },
        { "\033[3;_~", KEYC_DC },
};
static const key_code tty_default_xterm_modifiers[] = {
        0,
        0,
        KEYC_SHIFT,
        KEYC_META|KEYC_IMPLIED_META,
        KEYC_SHIFT|KEYC_META|KEYC_IMPLIED_META,
        KEYC_CTRL,
        KEYC_SHIFT|KEYC_CTRL,
        KEYC_META|KEYC_IMPLIED_META|KEYC_CTRL,
        KEYC_SHIFT|KEYC_META|KEYC_IMPLIED_META|KEYC_CTRL,
        KEYC_META|KEYC_IMPLIED_META
};

/*
 * Default terminfo(5) keys. Any keys that have builtin modifiers (that is,
 * where the key itself contains the modifiers) has the KEYC_XTERM flag set so
 * a leading escape is not treated as meta (and probably removed).
 */
struct tty_default_key_code {
        enum tty_code_code      code;
        key_code                key;
};
static const struct tty_default_key_code tty_default_code_keys[] = {
        /* Function keys. */
        { TTYC_KF1, KEYC_F1 },
        { TTYC_KF2, KEYC_F2 },
        { TTYC_KF3, KEYC_F3 },
        { TTYC_KF4, KEYC_F4 },
        { TTYC_KF5, KEYC_F5 },
        { TTYC_KF6, KEYC_F6 },
        { TTYC_KF7, KEYC_F7 },
        { TTYC_KF8, KEYC_F8 },
        { TTYC_KF9, KEYC_F9 },
        { TTYC_KF10, KEYC_F10 },
        { TTYC_KF11, KEYC_F11 },
        { TTYC_KF12, KEYC_F12 },

        { TTYC_KF13, KEYC_F1|KEYC_SHIFT },
        { TTYC_KF14, KEYC_F2|KEYC_SHIFT },
        { TTYC_KF15, KEYC_F3|KEYC_SHIFT },
        { TTYC_KF16, KEYC_F4|KEYC_SHIFT },
        { TTYC_KF17, KEYC_F5|KEYC_SHIFT },
        { TTYC_KF18, KEYC_F6|KEYC_SHIFT },
        { TTYC_KF19, KEYC_F7|KEYC_SHIFT },
        { TTYC_KF20, KEYC_F8|KEYC_SHIFT },
        { TTYC_KF21, KEYC_F9|KEYC_SHIFT },
        { TTYC_KF22, KEYC_F10|KEYC_SHIFT },
        { TTYC_KF23, KEYC_F11|KEYC_SHIFT },
        { TTYC_KF24, KEYC_F12|KEYC_SHIFT },

        { TTYC_KF25, KEYC_F1|KEYC_CTRL },
        { TTYC_KF26, KEYC_F2|KEYC_CTRL },
        { TTYC_KF27, KEYC_F3|KEYC_CTRL },
        { TTYC_KF28, KEYC_F4|KEYC_CTRL },
        { TTYC_KF29, KEYC_F5|KEYC_CTRL },
        { TTYC_KF30, KEYC_F6|KEYC_CTRL },
        { TTYC_KF31, KEYC_F7|KEYC_CTRL },
        { TTYC_KF32, KEYC_F8|KEYC_CTRL },
        { TTYC_KF33, KEYC_F9|KEYC_CTRL },
        { TTYC_KF34, KEYC_F10|KEYC_CTRL },
        { TTYC_KF35, KEYC_F11|KEYC_CTRL },
        { TTYC_KF36, KEYC_F12|KEYC_CTRL },

        { TTYC_KF37, KEYC_F1|KEYC_SHIFT|KEYC_CTRL },
        { TTYC_KF38, KEYC_F2|KEYC_SHIFT|KEYC_CTRL },
        { TTYC_KF39, KEYC_F3|KEYC_SHIFT|KEYC_CTRL },
        { TTYC_KF40, KEYC_F4|KEYC_SHIFT|KEYC_CTRL },
        { TTYC_KF41, KEYC_F5|KEYC_SHIFT|KEYC_CTRL },
        { TTYC_KF42, KEYC_F6|KEYC_SHIFT|KEYC_CTRL },
        { TTYC_KF43, KEYC_F7|KEYC_SHIFT|KEYC_CTRL },
        { TTYC_KF44, KEYC_F8|KEYC_SHIFT|KEYC_CTRL },
        { TTYC_KF45, KEYC_F9|KEYC_SHIFT|KEYC_CTRL },
        { TTYC_KF46, KEYC_F10|KEYC_SHIFT|KEYC_CTRL },
        { TTYC_KF47, KEYC_F11|KEYC_SHIFT|KEYC_CTRL },
        { TTYC_KF48, KEYC_F12|KEYC_SHIFT|KEYC_CTRL },

        { TTYC_KF49, KEYC_F1|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KF50, KEYC_F2|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KF51, KEYC_F3|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KF52, KEYC_F4|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KF53, KEYC_F5|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KF54, KEYC_F6|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KF55, KEYC_F7|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KF56, KEYC_F8|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KF57, KEYC_F9|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KF58, KEYC_F10|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KF59, KEYC_F11|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KF60, KEYC_F12|KEYC_META|KEYC_IMPLIED_META },

        { TTYC_KF61, KEYC_F1|KEYC_META|KEYC_IMPLIED_META|KEYC_SHIFT },
        { TTYC_KF62, KEYC_F2|KEYC_META|KEYC_IMPLIED_META|KEYC_SHIFT },
        { TTYC_KF63, KEYC_F3|KEYC_META|KEYC_IMPLIED_META|KEYC_SHIFT },

        { TTYC_KICH1, KEYC_IC },
        { TTYC_KDCH1, KEYC_DC },
        { TTYC_KHOME, KEYC_HOME },
        { TTYC_KEND, KEYC_END },
        { TTYC_KNP, KEYC_NPAGE },
        { TTYC_KPP, KEYC_PPAGE },
        { TTYC_KCBT, KEYC_BTAB },

        /* Arrow keys from terminfo. */
        { TTYC_KCUU1, KEYC_UP|KEYC_CURSOR },
        { TTYC_KCUD1, KEYC_DOWN|KEYC_CURSOR },
        { TTYC_KCUB1, KEYC_LEFT|KEYC_CURSOR },
        { TTYC_KCUF1, KEYC_RIGHT|KEYC_CURSOR },

        /* Key and modifier capabilities. */
        { TTYC_KDC2, KEYC_DC|KEYC_SHIFT },
        { TTYC_KDC3, KEYC_DC|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KDC4, KEYC_DC|KEYC_SHIFT|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KDC5, KEYC_DC|KEYC_CTRL },
        { TTYC_KDC6, KEYC_DC|KEYC_SHIFT|KEYC_CTRL },
        { TTYC_KDC7, KEYC_DC|KEYC_META|KEYC_IMPLIED_META|KEYC_CTRL },
        { TTYC_KIND, KEYC_DOWN|KEYC_SHIFT },
        { TTYC_KDN2, KEYC_DOWN|KEYC_SHIFT },
        { TTYC_KDN3, KEYC_DOWN|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KDN4, KEYC_DOWN|KEYC_SHIFT|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KDN5, KEYC_DOWN|KEYC_CTRL },
        { TTYC_KDN6, KEYC_DOWN|KEYC_SHIFT|KEYC_CTRL },
        { TTYC_KDN7, KEYC_DOWN|KEYC_META|KEYC_IMPLIED_META|KEYC_CTRL },
        { TTYC_KEND2, KEYC_END|KEYC_SHIFT },
        { TTYC_KEND3, KEYC_END|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KEND4, KEYC_END|KEYC_SHIFT|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KEND5, KEYC_END|KEYC_CTRL },
        { TTYC_KEND6, KEYC_END|KEYC_SHIFT|KEYC_CTRL },
        { TTYC_KEND7, KEYC_END|KEYC_META|KEYC_IMPLIED_META|KEYC_CTRL },
        { TTYC_KHOM2, KEYC_HOME|KEYC_SHIFT },
        { TTYC_KHOM3, KEYC_HOME|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KHOM4, KEYC_HOME|KEYC_SHIFT|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KHOM5, KEYC_HOME|KEYC_CTRL },
        { TTYC_KHOM6, KEYC_HOME|KEYC_SHIFT|KEYC_CTRL },
        { TTYC_KHOM7, KEYC_HOME|KEYC_META|KEYC_IMPLIED_META|KEYC_CTRL },
        { TTYC_KIC2, KEYC_IC|KEYC_SHIFT },
        { TTYC_KIC3, KEYC_IC|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KIC4, KEYC_IC|KEYC_SHIFT|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KIC5, KEYC_IC|KEYC_CTRL },
        { TTYC_KIC6, KEYC_IC|KEYC_SHIFT|KEYC_CTRL },
        { TTYC_KIC7, KEYC_IC|KEYC_META|KEYC_IMPLIED_META|KEYC_CTRL },
        { TTYC_KLFT2, KEYC_LEFT|KEYC_SHIFT },
        { TTYC_KLFT3, KEYC_LEFT|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KLFT4, KEYC_LEFT|KEYC_SHIFT|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KLFT5, KEYC_LEFT|KEYC_CTRL },
        { TTYC_KLFT6, KEYC_LEFT|KEYC_SHIFT|KEYC_CTRL },
        { TTYC_KLFT7, KEYC_LEFT|KEYC_META|KEYC_IMPLIED_META|KEYC_CTRL },
        { TTYC_KNXT2, KEYC_NPAGE|KEYC_SHIFT },
        { TTYC_KNXT3, KEYC_NPAGE|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KNXT4, KEYC_NPAGE|KEYC_SHIFT|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KNXT5, KEYC_NPAGE|KEYC_CTRL },
        { TTYC_KNXT6, KEYC_NPAGE|KEYC_SHIFT|KEYC_CTRL },
        { TTYC_KNXT7, KEYC_NPAGE|KEYC_META|KEYC_IMPLIED_META|KEYC_CTRL },
        { TTYC_KPRV2, KEYC_PPAGE|KEYC_SHIFT },
        { TTYC_KPRV3, KEYC_PPAGE|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KPRV4, KEYC_PPAGE|KEYC_SHIFT|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KPRV5, KEYC_PPAGE|KEYC_CTRL },
        { TTYC_KPRV6, KEYC_PPAGE|KEYC_SHIFT|KEYC_CTRL },
        { TTYC_KPRV7, KEYC_PPAGE|KEYC_META|KEYC_IMPLIED_META|KEYC_CTRL },
        { TTYC_KRIT2, KEYC_RIGHT|KEYC_SHIFT },
        { TTYC_KRIT3, KEYC_RIGHT|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KRIT4, KEYC_RIGHT|KEYC_SHIFT|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KRIT5, KEYC_RIGHT|KEYC_CTRL },
        { TTYC_KRIT6, KEYC_RIGHT|KEYC_SHIFT|KEYC_CTRL },
        { TTYC_KRIT7, KEYC_RIGHT|KEYC_META|KEYC_IMPLIED_META|KEYC_CTRL },
        { TTYC_KRI, KEYC_UP|KEYC_SHIFT },
        { TTYC_KUP2, KEYC_UP|KEYC_SHIFT },
        { TTYC_KUP3, KEYC_UP|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KUP4, KEYC_UP|KEYC_SHIFT|KEYC_META|KEYC_IMPLIED_META },
        { TTYC_KUP5, KEYC_UP|KEYC_CTRL },
        { TTYC_KUP6, KEYC_UP|KEYC_SHIFT|KEYC_CTRL },
        { TTYC_KUP7, KEYC_UP|KEYC_META|KEYC_IMPLIED_META|KEYC_CTRL },
};

/* Add key to tree. */
static void
tty_keys_add(struct tty *tty, const char *s, key_code key)
{
        struct tty_key  *tk;
        size_t           size;
        const char      *keystr;

        keystr = key_string_lookup_key(key, 1);
        if ((tk = tty_keys_find(tty, s, strlen(s), &size)) == NULL) {
                log_debug("new key %s: 0x%llx (%s)", s, key, keystr);
                tty_keys_add1(&tty->key_tree, s, key);
        } else {
                log_debug("replacing key %s: 0x%llx (%s)", s, key, keystr);
                tk->key = key;
        }
}

/* Add next node to the tree. */
static void
tty_keys_add1(struct tty_key **tkp, const char *s, key_code key)
{
        struct tty_key  *tk;

        /* Allocate a tree entry if there isn't one already. */
        tk = *tkp;
        if (tk == NULL) {
                tk = *tkp = xcalloc(1, sizeof *tk);
                tk->ch = *s;
                tk->key = KEYC_UNKNOWN;
        }

        /* Find the next entry. */
        if (*s == tk->ch) {
                /* Move forward in string. */
                s++;

                /* If this is the end of the string, no more is necessary. */
                if (*s == '\0') {
                        tk->key = key;
                        return;
                }

                /* Use the child tree for the next character. */
                tkp = &tk->next;
        } else {
                if (*s < tk->ch)
                        tkp = &tk->left;
                else if (*s > tk->ch)
                        tkp = &tk->right;
        }

        /* And recurse to add it. */
        tty_keys_add1(tkp, s, key);
}

/* Initialise a key tree from the table. */
void
tty_keys_build(struct tty *tty)
{
        const struct tty_default_key_raw        *tdkr;
        const struct tty_default_key_xterm      *tdkx;
        const struct tty_default_key_code       *tdkc;
        u_int                                    i, j;
        const char                              *s;
        struct options_entry                    *o;
        struct options_array_item               *a;
        union options_value                     *ov;
        char                                     copy[16];
        key_code                                 key;

        if (tty->key_tree != NULL)
                tty_keys_free(tty);
        tty->key_tree = NULL;

        for (i = 0; i < nitems(tty_default_xterm_keys); i++) {
                tdkx = &tty_default_xterm_keys[i];
                for (j = 2; j < nitems(tty_default_xterm_modifiers); j++) {
                        strlcpy(copy, tdkx->template, sizeof copy);
                        copy[strcspn(copy, "_")] = '0' + j;

                        key = tdkx->key|tty_default_xterm_modifiers[j];
                        tty_keys_add(tty, copy, key);
                }
        }
        for (i = 0; i < nitems(tty_default_raw_keys); i++) {
                tdkr = &tty_default_raw_keys[i];

                s = tdkr->string;
                if (*s != '\0')
                        tty_keys_add(tty, s, tdkr->key);
        }
        for (i = 0; i < nitems(tty_default_code_keys); i++) {
                tdkc = &tty_default_code_keys[i];

                s = tty_term_string(tty->term, tdkc->code);
                if (*s != '\0')
                        tty_keys_add(tty, s, tdkc->key);

        }

        o = options_get(global_options, "user-keys");
        if (o != NULL) {
                a = options_array_first(o);
                while (a != NULL) {
                        i = options_array_item_index(a);
                        ov = options_array_item_value(a);
                        tty_keys_add(tty, ov->string, KEYC_USER + i);
                        a = options_array_next(a);
                }
        }
}

/* Free the entire key tree. */
void
tty_keys_free(struct tty *tty)
{
        tty_keys_free1(tty->key_tree);
}

/* Free a single key. */
static void
tty_keys_free1(struct tty_key *tk)
{
        if (tk->next != NULL)
                tty_keys_free1(tk->next);
        if (tk->left != NULL)
                tty_keys_free1(tk->left);
        if (tk->right != NULL)
                tty_keys_free1(tk->right);
        free(tk);
}

/* Lookup a key in the tree. */
static struct tty_key *
tty_keys_find(struct tty *tty, const char *buf, size_t len, size_t *size)
{
        *size = 0;
        return (tty_keys_find1(tty->key_tree, buf, len, size));
}

/* Find the next node. */
static struct tty_key *
tty_keys_find1(struct tty_key *tk, const char *buf, size_t len, size_t *size)
{
        /* If no data, no match. */
        if (len == 0)
                return (NULL);

        /* If the node is NULL, this is the end of the tree. No match. */
        if (tk == NULL)
                return (NULL);

        /* Pick the next in the sequence. */
        if (tk->ch == *buf) {
                /* Move forward in the string. */
                buf++; len--;
                (*size)++;

                /* At the end of the string, return the current node. */
                if (len == 0 || (tk->next == NULL && tk->key != KEYC_UNKNOWN))
                        return (tk);

                /* Move into the next tree for the following character. */
                tk = tk->next;
        } else {
                if (*buf < tk->ch)
                        tk = tk->left;
                else if (*buf > tk->ch)
                        tk = tk->right;
        }

        /* Move to the next in the tree. */
        return (tty_keys_find1(tk, buf, len, size));
}

/* Look up part of the next key. */
static int
tty_keys_next1(struct tty *tty, const char *buf, size_t len, key_code *key,
    size_t *size, int expired)
{
        struct client           *c = tty->client;
        struct tty_key          *tk, *tk1;
        struct utf8_data         ud;
        enum utf8_state          more;
        utf8_char                uc;
        u_int                    i;

        log_debug("%s: next key is %zu (%.*s) (expired=%d)", c->name, len,
            (int)len, buf, expired);

        /* Is this a known key? */
        tk = tty_keys_find(tty, buf, len, size);
        if (tk != NULL && tk->key != KEYC_UNKNOWN) {
                tk1 = tk;
                do
                        log_debug("%s: keys in list: %#llx", c->name, tk1->key);
                while ((tk1 = tk1->next) != NULL);
                if (tk->next != NULL && !expired)
                        return (1);
                *key = tk->key;
                return (0);
        }

        /* Is this valid UTF-8? */
        more = utf8_open(&ud, (u_char)*buf);
        if (more == UTF8_MORE) {
                *size = ud.size;
                if (len < ud.size) {
                        if (!expired)
                                return (1);
                        return (-1);
                }
                for (i = 1; i < ud.size; i++)
                        more = utf8_append(&ud, (u_char)buf[i]);
                if (more != UTF8_DONE)
                        return (-1);

                if (utf8_from_data(&ud, &uc) != UTF8_DONE)
                        return (-1);
                *key = uc;

                log_debug("%s: UTF-8 key %.*s %#llx", c->name, (int)ud.size,
                    ud.data, *key);
                return (0);
        }

        return (-1);
}

/* Process window size change escape sequences. */
static int
tty_keys_winsz(struct tty *tty, const char *buf, size_t len, size_t *size)
{
        struct client   *c = tty->client;
        size_t           end;
        char             tmp[64];
        u_int            sx, sy, xpixel, ypixel, char_x, char_y;

        *size = 0;

        /* If we did not request this, ignore it. */
        if (!(tty->flags & TTY_WINSIZEQUERY))
                return (-1);

        /* First two bytes are always \033[. */
        if (buf[0] != '\033')
                return (-1);
        if (len == 1)
                return (1);
        if (buf[1] != '[')
                return (-1);
        if (len == 2)
                return (1);

        /*
         * Stop at either 't' or anything that isn't a
         * number or ';'.
         */
        for (end = 2; end < len && end != sizeof tmp; end++) {
                if (buf[end] == 't')
                        break;
                if (!isdigit((u_char)buf[end]) && buf[end] != ';')
                        break;
        }
        if (end == len)
                return (1);
        if (end == sizeof tmp || buf[end] != 't')
                return (-1);

        /* Copy to the buffer. */
        memcpy(tmp, buf + 2, end - 2);
        tmp[end - 2] = '\0';

        /* Try to parse the window size sequence. */
        if (sscanf(tmp, "8;%u;%u", &sy, &sx) == 2) {
                /* Window size in characters. */
                tty_set_size(tty, sx, sy, tty->xpixel, tty->ypixel);

                *size = end + 1;
                return (0);
        } else if (sscanf(tmp, "4;%u;%u", &ypixel, &xpixel) == 2) {
                /* Window size in pixels. */
                char_x = (xpixel && tty->sx) ? xpixel / tty->sx : 0;
                char_y = (ypixel && tty->sy) ? ypixel / tty->sy : 0;
                tty_set_size(tty, tty->sx, tty->sy, char_x, char_y);
                tty_invalidate(tty);

                tty->flags &= ~TTY_WINSIZEQUERY;
                *size = end + 1;
                return (0);
        }

        log_debug("%s: unrecognized window size sequence: %s", c->name, tmp);
        return (-1);
}


/* Process at least one key in the buffer. Return 0 if no keys present. */
int
tty_keys_next(struct tty *tty)
{
        struct client           *c = tty->client;
        struct timeval           tv;
        const char              *buf;
        size_t                   len, size;
        cc_t                     bspace;
        int                      delay, expired = 0, n;
        key_code                 key, onlykey;
        struct mouse_event       m = { 0 };
        struct key_event        *event;

        /* Get key buffer. */
        buf = EVBUFFER_DATA(tty->in);
        len = EVBUFFER_LENGTH(tty->in);
        if (len == 0)
                return (0);
        log_debug("%s: keys are %zu (%.*s)", c->name, len, (int)len, buf);

        /* Is this a clipboard response? */
        switch (tty_keys_clipboard(tty, buf, len, &size)) {
        case 0:         /* yes */
                key = KEYC_UNKNOWN;
                goto complete_key;
        case -1:        /* no, or not valid */
                break;
        case 1:         /* partial */
                goto partial_key;
        }

        /* Is this a primary device attributes response? */
        switch (tty_keys_device_attributes(tty, buf, len, &size)) {
        case 0:         /* yes */
                key = KEYC_UNKNOWN;
                goto complete_key;
        case -1:        /* no, or not valid */
                break;
        case 1:         /* partial */
                goto partial_key;
        }

        /* Is this a secondary device attributes response? */
        switch (tty_keys_device_attributes2(tty, buf, len, &size)) {
        case 0:         /* yes */
                key = KEYC_UNKNOWN;
                goto complete_key;
        case -1:        /* no, or not valid */
                break;
        case 1:         /* partial */
                goto partial_key;
        }

        /* Is this an extended device attributes response? */
        switch (tty_keys_extended_device_attributes(tty, buf, len, &size)) {
        case 0:         /* yes */
                key = KEYC_UNKNOWN;
                goto complete_key;
        case -1:        /* no, or not valid */
                break;
        case 1:         /* partial */
                goto partial_key;
        }

        /* Is this a colours response? */
        switch (tty_keys_colours(tty, buf, len, &size, &tty->fg, &tty->bg)) {
        case 0:         /* yes */
                key = KEYC_UNKNOWN;
                session_theme_changed(c->session);
                goto complete_key;
        case -1:        /* no, or not valid */
                break;
        case 1:         /* partial */
                session_theme_changed(c->session);
                goto partial_key;
        }

        /* Is this a palette response? */
        switch (tty_keys_palette(tty, buf, len, &size)) {
        case 0:         /* yes */
                key = KEYC_UNKNOWN;
                goto complete_key;
        case -1:        /* no, or not valid */
                break;
        case 1:         /* partial */
                goto partial_key;
        }

        /* Is this a mouse key press? */
        switch (tty_keys_mouse(tty, buf, len, &size, &m)) {
        case 0:         /* yes */
                key = KEYC_MOUSE;
                goto complete_key;
        case -1:        /* no, or not valid */
                break;
        case -2:        /* yes, but we don't care. */
                key = KEYC_MOUSE;
                goto discard_key;
        case 1:         /* partial */
                goto partial_key;
        }

        /* Is this an extended key press? */
        switch (tty_keys_extended_key(tty, buf, len, &size, &key)) {
        case 0:         /* yes */
                goto complete_key;
        case -1:        /* no, or not valid */
                break;
        case 1:         /* partial */
                goto partial_key;
        }

        /* Check for window size query */
        switch (tty_keys_winsz(tty, buf, len, &size)) {
        case 0:         /* yes */
                key = KEYC_UNKNOWN;
                goto complete_key;
        case -1:        /* no, or not valid */
                break;
        case 1:         /* partial */
                goto partial_key;
        }

first_key:
        /* Try to lookup complete key. */
        n = tty_keys_next1(tty, buf, len, &key, &size, expired);
        if (n == 0)     /* found */
                goto complete_key;
        if (n == 1)
                goto partial_key;

        /*
         * If not a complete key, look for key with an escape prefix (meta
         * modifier).
         */
        if (*buf == '\033' && len > 1) {
                /* Look for a key without the escape. */
                n = tty_keys_next1(tty, buf + 1, len - 1, &key, &size, expired);
                if (n == 0) {   /* found */
                        if (key & KEYC_IMPLIED_META) {
                                /*
                                 * We want the escape key as well as the xterm
                                 * key, because the xterm sequence implicitly
                                 * includes the escape (so if we see
                                 * \033\033[1;3D we know it is an Escape
                                 * followed by M-Left, not just M-Left).
                                 */
                                key = '\033';
                                size = 1;
                                goto complete_key;
                        }
                        key |= KEYC_META;
                        size++;
                        goto complete_key;
                }
                if (n == 1)     /* partial */
                        goto partial_key;
        }

        /*
         * At this point, we know the key is not partial (with or without
         * escape). So pass it through even if the timer has not expired.
         */
        if (*buf == '\033' && len >= 2) {
                key = (u_char)buf[1] | KEYC_META;
                size = 2;
        } else {
                key = (u_char)buf[0];
                size = 1;
        }

        /* C-Space is special. */
        if ((key & KEYC_MASK_KEY) == C0_NUL)
                key = ' ' | KEYC_CTRL | (key & KEYC_META);

        /*
         * Check for backspace key using termios VERASE - the terminfo
         * kbs entry is extremely unreliable, so cannot be safely
         * used. termios should have a better idea.
         */
        bspace = tty->tio.c_cc[VERASE];
        if (bspace != _POSIX_VDISABLE) {
                if (key == bspace) {
                        log_debug("%s: key %#llx is BSpace", c->name, key);
                        key = KEYC_BSPACE;
                }
                if (key == (bspace|KEYC_META)) {
                        log_debug("%s: key %#llx is M-BSpace", c->name, key);
                        key = KEYC_BSPACE|KEYC_META;
                }
        }

        /*
         * Fix up all C0 control codes that don't have a dedicated key into
         * corresponding Ctrl keys. Convert characters in the A-Z range into
         * lowercase, so ^A becomes a|CTRL.
         */
        onlykey = key & KEYC_MASK_KEY;
        if (onlykey < 0x20 &&
            onlykey != C0_HT &&
            onlykey != C0_CR &&
            onlykey != C0_ESC) {
                onlykey |= 0x40;
                if (onlykey >= 'A' && onlykey <= 'Z')
                        onlykey |= 0x20;
                key = onlykey | KEYC_CTRL | (key & KEYC_META);
        }

        goto complete_key;

partial_key:
        log_debug("%s: partial key %.*s", c->name, (int)len, buf);

        /* If timer is going, check for expiration. */
        if (tty->flags & TTY_TIMER) {
                if (evtimer_initialized(&tty->key_timer) &&
                    !evtimer_pending(&tty->key_timer, NULL)) {
                        expired = 1;
                        goto first_key;
                }
                return (0);
        }

        /* Get the time period. */
        delay = options_get_number(global_options, "escape-time");
        if (delay == 0)
                delay = 1;
        if ((tty->flags & (TTY_WAITFG|TTY_WAITBG) ||
            (tty->flags & TTY_ALL_REQUEST_FLAGS) != TTY_ALL_REQUEST_FLAGS) ||
            !TAILQ_EMPTY(&c->input_requests)) {
                log_debug("%s: increasing delay for active query", c->name);
                if (delay < 500)
                        delay = 500;
        }
        tv.tv_sec = delay / 1000;
        tv.tv_usec = (delay % 1000) * 1000L;

        /* Start the timer. */
        if (event_initialized(&tty->key_timer))
                evtimer_del(&tty->key_timer);
        evtimer_set(&tty->key_timer, tty_keys_callback, tty);
        evtimer_add(&tty->key_timer, &tv);

        tty->flags |= TTY_TIMER;
        return (0);

complete_key:
        log_debug("%s: complete key %.*s %#llx", c->name, (int)size, buf, key);

        /* Remove key timer. */
        if (event_initialized(&tty->key_timer))
                evtimer_del(&tty->key_timer);
        tty->flags &= ~TTY_TIMER;

        /* Check for focus events. */
        if (key == KEYC_FOCUS_OUT) {
                c->flags &= ~CLIENT_FOCUSED;
                window_update_focus(c->session->curw->window);
                notify_client("client-focus-out", c);
        } else if (key == KEYC_FOCUS_IN) {
                c->flags |= CLIENT_FOCUSED;
                notify_client("client-focus-in", c);
                window_update_focus(c->session->curw->window);
        }

        /* Fire the key. */
        if (key != KEYC_UNKNOWN) {
                event = xcalloc(1, sizeof *event);
                event->key = key;
                memcpy(&event->m, &m, sizeof event->m);

                event->buf = xmalloc(size);
                event->len = size;
                memcpy (event->buf, buf, event->len);

                if (!server_client_handle_key(c, event)) {
                        free(event->buf);
                        free(event);
                }
        }

        /* Remove data from buffer. */
        evbuffer_drain(tty->in, size);

        return (1);

discard_key:
        log_debug("%s: discard key %.*s %#llx", c->name, (int)size, buf, key);

        /* Remove data from buffer. */
        evbuffer_drain(tty->in, size);

        return (1);
}

/* Key timer callback. */
static void
tty_keys_callback(__unused int fd, __unused short events, void *data)
{
        struct tty      *tty = data;

        if (tty->flags & TTY_TIMER) {
                while (tty_keys_next(tty))
                        ;
        }
}

/*
 * Handle extended key input. This has two forms: \033[27;m;k~ and \033[k;mu,
 * where k is key as a number and m is a modifier. Returns 0 for success, -1
 * for failure, 1 for partial;
 */
static int
tty_keys_extended_key(struct tty *tty, const char *buf, size_t len,
    size_t *size, key_code *key)
{
        struct client   *c = tty->client;
        size_t           end;
        u_int            number, modifiers;
        char             tmp[64];
        cc_t             bspace;
        key_code         nkey, onlykey;
        struct utf8_data ud;
        utf8_char        uc;

        *size = 0;

        /* First two bytes are always \033[. */
        if (buf[0] != '\033')
                return (-1);
        if (len == 1)
                return (1);
        if (buf[1] != '[')
                return (-1);
        if (len == 2)
                return (1);

        /*
         * Look for a terminator. Stop at either '~' or anything that isn't a
         * number or ';'.
         */
        for (end = 2; end < len && end != sizeof tmp; end++) {
                if (buf[end] == '~')
                        break;
                if (!isdigit((u_char)buf[end]) && buf[end] != ';')
                        break;
        }
        if (end == len)
                return (1);
        if (end == sizeof tmp || (buf[end] != '~' && buf[end] != 'u'))
                return (-1);

        /* Copy to the buffer. */
        memcpy(tmp, buf + 2, end - 2);
        tmp[end - 2] = '\0';

        /* Try to parse either form of key. */
        if (buf[end] == '~') {
                if (sscanf(tmp, "27;%u;%u", &modifiers, &number) != 2)
                        return (-1);
        } else {
                if (sscanf(tmp ,"%u;%u", &number, &modifiers) != 2)
                        return (-1);
        }
        *size = end + 1;

        /* Store the key. */
        bspace = tty->tio.c_cc[VERASE];
        if (bspace != _POSIX_VDISABLE && number == bspace)
                nkey = KEYC_BSPACE;
        else
                nkey = number;

        /* Convert UTF-32 codepoint into internal representation. */
        if (nkey != KEYC_BSPACE && nkey & ~0x7f) {
                if (utf8_fromwc(nkey, &ud) == UTF8_DONE &&
                    utf8_from_data(&ud, &uc) == UTF8_DONE)
                        nkey = uc;
                else
                        return (-1);
        }

        /* Update the modifiers. */
        if (modifiers > 0) {
                modifiers--;
                if (modifiers & 1)
                        nkey |= KEYC_SHIFT;
                if (modifiers & 2)
                        nkey |= (KEYC_META|KEYC_IMPLIED_META); /* Alt */
                if (modifiers & 4)
                        nkey |= KEYC_CTRL;
                if (modifiers & 8)
                        nkey |= (KEYC_META|KEYC_IMPLIED_META); /* Meta */
        }

        /* Convert S-Tab into Backtab. */
        if ((nkey & KEYC_MASK_KEY) == '\011' && (nkey & KEYC_SHIFT))
                nkey = KEYC_BTAB | (nkey & ~KEYC_MASK_KEY & ~KEYC_SHIFT);

        /*
         * Deal with the Shift modifier when present alone. The problem is that
         * in mode 2 some terminals would report shifted keys, like S-a, as
         * just A, and some as S-A.
         *
         * Because we need an unambiguous internal representation, and because
         * restoring the Shift modifier when it's missing would require knowing
         * the keyboard layout, and because S-A would cause a lot of issues
         * downstream, we choose to lose the Shift for all printable
         * characters.
         *
         * That still leaves some ambiguity, such as C-S-A vs. C-A, but that's
         * OK, and applications can handle that.
         */
        onlykey = nkey & KEYC_MASK_KEY;
        if (((onlykey > 0x20 && onlykey < 0x7f) ||
            KEYC_IS_UNICODE(nkey)) &&
            (nkey & KEYC_MASK_MODIFIERS) == KEYC_SHIFT)
                nkey &= ~KEYC_SHIFT;

        if (log_get_level() != 0) {
                log_debug("%s: extended key %.*s is %llx (%s)", c->name,
                    (int)*size, buf, nkey, key_string_lookup_key(nkey, 1));
        }

        *key = nkey;
        return (0);
}

/*
 * Handle mouse key input. Returns 0 for success, -1 for failure, 1 for partial
 * (probably a mouse sequence but need more data), -2 if an invalid mouse
 * sequence.
 */
static int
tty_keys_mouse(struct tty *tty, const char *buf, size_t len, size_t *size,
    struct mouse_event *m)
{
        struct client   *c = tty->client;
        u_int            i, x, y, b, sgr_b;
        u_char           sgr_type, ch;

        /*
         * Standard mouse sequences are \033[M followed by three characters
         * indicating button, X and Y, all based at 32 with 1,1 top-left.
         *
         * UTF-8 mouse sequences are similar but the three are expressed as
         * UTF-8 characters.
         *
         * SGR extended mouse sequences are \033[< followed by three numbers in
         * decimal and separated by semicolons indicating button, X and Y. A
         * trailing 'M' is click or scroll and trailing 'm' release. All are
         * based at 0 with 1,1 top-left.
         */

        *size = 0;
        x = y = b = sgr_b = 0;
        sgr_type = ' ';

        /* First two bytes are always \033[. */
        if (buf[0] != '\033')
                return (-1);
        if (len == 1)
                return (1);
        if (buf[1] != '[')
                return (-1);
        if (len == 2)
                return (1);

        /*
         * Third byte is M in old standard (and UTF-8 extension which we do not
         * support), < in SGR extension.
         */
        if (buf[2] == 'M') {
                /* Read the three inputs. */
                *size = 3;
                for (i = 0; i < 3; i++) {
                        if (len <= *size)
                                return (1);
                        ch = (u_char)buf[(*size)++];
                        if (i == 0)
                                b = ch;
                        else if (i == 1)
                                x = ch;
                        else
                                y = ch;
                }
                log_debug("%s: mouse input: %.*s", c->name, (int)*size, buf);

                /* Check and return the mouse input. */
                if (b < MOUSE_PARAM_BTN_OFF ||
                    x < MOUSE_PARAM_POS_OFF ||
                    y < MOUSE_PARAM_POS_OFF)
                        return (-2);
                b -= MOUSE_PARAM_BTN_OFF;
                x -= MOUSE_PARAM_POS_OFF;
                y -= MOUSE_PARAM_POS_OFF;
        } else if (buf[2] == '<') {
                /* Read the three inputs. */
                *size = 3;
                while (1) {
                        if (len <= *size)
                                return (1);
                        ch = (u_char)buf[(*size)++];
                        if (ch == ';')
                                break;
                        if (ch < '0' || ch > '9')
                                return (-1);
                        sgr_b = 10 * sgr_b + (ch - '0');
                }
                while (1) {
                        if (len <= *size)
                                return (1);
                        ch = (u_char)buf[(*size)++];
                        if (ch == ';')
                                break;
                        if (ch < '0' || ch > '9')
                                return (-1);
                        x = 10 * x + (ch - '0');
                }
                while (1) {
                        if (len <= *size)
                                return (1);
                        ch = (u_char)buf[(*size)++];
                        if (ch == 'M' || ch == 'm')
                                break;
                        if (ch < '0' || ch > '9')
                                return (-1);
                        y = 10 * y + (ch - '0');
                }
                log_debug("%s: mouse input (SGR): %.*s", c->name, (int)*size,
                    buf);

                /* Check and return the mouse input. */
                if (x < 1 || y < 1)
                        return (-2);
                x--;
                y--;
                b = sgr_b;

                /* Type is M for press, m for release. */
                sgr_type = ch;
                if (sgr_type == 'm')
                        b = 3;

                /*
                 * Some terminals (like PuTTY 0.63) mistakenly send
                 * button-release events for scroll-wheel button-press event.
                 * Discard it before it reaches any program running inside
                 * tmux.
                 */
                if (sgr_type == 'm' && MOUSE_WHEEL(sgr_b))
                    return (-2);
        } else
                return (-1);

        /* Fill mouse event. */
        m->lx = tty->mouse_last_x;
        m->x = x;
        m->ly = tty->mouse_last_y;
        m->y = y;
        m->lb = tty->mouse_last_b;
        m->b = b;
        m->sgr_type = sgr_type;
        m->sgr_b = sgr_b;

        /* Update last mouse state. */
        tty->mouse_last_x = x;
        tty->mouse_last_y = y;
        tty->mouse_last_b = b;

        return (0);
}

/*
 * Handle OSC 52 clipboard input. Returns 0 for success, -1 for failure, 1 for
 * partial.
 */
static int
tty_keys_clipboard(struct tty *tty, const char *buf, size_t len, size_t *size)
{
        struct client                           *c = tty->client;
        size_t                                   end, terminator = 0, needed;
        char                                    *copy, *out, clip = 0;
        int                                      outlen;
        struct input_request_clipboard_data      cd;

        *size = 0;

        /* First five bytes are always \033]52;. */
        if (buf[0] != '\033')
                return (-1);
        if (len == 1)
                return (1);
        if (buf[1] != ']')
                return (-1);
        if (len == 2)
                return (1);
        if (buf[2] != '5')
                return (-1);
        if (len == 3)
                return (1);
        if (buf[3] != '2')
                return (-1);
        if (len == 4)
                return (1);
        if (buf[4] != ';')
                return (-1);
        if (len == 5)
                return (1);

        /* Find the terminator if any. */
        for (end = 5; end < len; end++) {
                if (buf[end] == '\007') {
                        terminator = 1;
                        break;
                }
                if (end > 5 && buf[end - 1] == '\033' && buf[end] == '\\') {
                        terminator = 2;
                        break;
                }
        }
        if (end == len)
                return (1);
        *size = end + 1;

        /* Skip the initial part. */
        buf += 5;
        end -= 5;

        /* Adjust end so that it points to the start of the terminator. */
        end -= terminator - 1;

        /*
         * Save which clipboard was used from the second argument. If more than
         * one is specified (should not happen), ignore the argument.
         */
        if (end >= 2 && buf[0] != ';' && buf[1] == ';')
                clip = buf[0];

        /* Skip the second argument. */
        while (end != 0 && *buf != ';') {
                buf++;
                end--;
        }
        if (end == 0 || end == 1)
                return (0);
        buf++;
        end--;

        /* It has to be a string so copy it. */
        copy = xmalloc(end + 1);
        memcpy(copy, buf, end);
        copy[end] = '\0';

        /* Convert from base64. */
        needed = ((end + 3) / 4) * 3;
        if (needed == 0) {
                free(copy);
                return (0);
        }
        out = xmalloc(needed);
        if ((outlen = b64_pton(copy, out, needed)) == -1) {
                free(out);
                free(copy);
                return (0);
        }
        free(copy);
        log_debug("%s: %.*s", __func__, outlen, out);

        /* Set reply if any. */
        cd.buf = out;
        cd.len = outlen;
        cd.clip = clip;
        input_request_reply(c, INPUT_REQUEST_CLIPBOARD, &cd);

        /* Create a buffer if requested. */
        if (tty->flags & TTY_OSC52QUERY) {
                paste_add(NULL, out, outlen);
                out = NULL;
                evtimer_del(&tty->clipboard_timer);
                tty->flags &= ~TTY_OSC52QUERY;
        }

        free(out);
        return (0);
}

/*
 * Handle primary device attributes input. Returns 0 for success, -1 for
 * failure, 1 for partial.
 */
static int
tty_keys_device_attributes(struct tty *tty, const char *buf, size_t len,
    size_t *size)
{
        struct client   *c = tty->client;
        int             *features = &c->term_features;
        u_int            i, n = 0;
        char             tmp[128], *endptr, p[32] = { 0 }, *cp, *next;

        *size = 0;
        if (tty->flags & TTY_HAVEDA)
                return (-1);

        /* First three bytes are always \033[?. */
        if (buf[0] != '\033')
                return (-1);
        if (len == 1)
                return (1);
        if (buf[1] != '[')
                return (-1);
        if (len == 2)
                return (1);
        if (buf[2] != '?')
                return (-1);
        if (len == 3)
                return (1);

        /* Copy the rest up to a c. */
        for (i = 0; i < sizeof tmp; i++) {
                if (3 + i == len)
                        return (1);
                if (buf[3 + i] >= 'a' && buf[3 + i] <= 'z')
                        break;
                tmp[i] = buf[3 + i];
        }
        if (i == sizeof tmp)
                return (-1);
        if (buf[3 + i] != 'c')
                return (-1);
        tmp[i] = '\0';
        *size = 4 + i;

        /* Convert all arguments to numbers. */
        cp = tmp;
        while ((next = strsep(&cp, ";")) != NULL) {
                p[n] = strtoul(next, &endptr, 10);
                if (*endptr != '\0')
                        p[n] = 0;
                if (++n == nitems(p))
                        break;
        }

        /* Add terminal features. */
        switch (p[0]) {
        case 61: /* level 1 */
        case 62: /* level 2 */
        case 63: /* level 3 */
        case 64: /* level 4 */
        case 65: /* level 5 */
                for (i = 1; i < n; i++) {
                        log_debug("%s: DA feature: %d", c->name, p[i]);
                        if (p[i] == 4)
                                tty_add_features(features, "sixel", ",");
                        if (p[i] == 21)
                                tty_add_features(features, "margins", ",");
                        if (p[i] == 28)
                                tty_add_features(features, "rectfill", ",");
                        if (p[i] == 52)
                                tty_add_features(features, "clipboard", ",");
                }
                break;
        }
        log_debug("%s: received primary DA %.*s", c->name, (int)*size, buf);

        tty_update_features(tty);
        tty->flags |= TTY_HAVEDA;

        return (0);
}

/*
 * Handle secondary device attributes input. Returns 0 for success, -1 for
 * failure, 1 for partial.
 */
static int
tty_keys_device_attributes2(struct tty *tty, const char *buf, size_t len,
    size_t *size)
{
        struct client   *c = tty->client;
        int             *features = &c->term_features;
        u_int            i, n = 0;
        char             tmp[128], *endptr, p[32] = { 0 }, *cp, *next;

        *size = 0;
        if (tty->flags & TTY_HAVEDA2)
                return (-1);

        /* First three bytes are always \033[>. */
        if (buf[0] != '\033')
                return (-1);
        if (len == 1)
                return (1);
        if (buf[1] != '[')
                return (-1);
        if (len == 2)
                return (1);
        if (buf[2] != '>')
                return (-1);
        if (len == 3)
                return (1);

        /* Copy the rest up to a c. */
        for (i = 0; i < sizeof tmp; i++) {
                if (3 + i == len)
                        return (1);
                if (buf[3 + i] >= 'a' && buf[3 + i] <= 'z')
                        break;
                tmp[i] = buf[3 + i];
        }
        if (i == sizeof tmp)
                return (-1);
        if (buf[3 + i] != 'c')
                return (-1);
        tmp[i] = '\0';
        *size = 4 + i;

        /* Convert all arguments to numbers. */
        cp = tmp;
        while ((next = strsep(&cp, ";")) != NULL) {
                p[n] = strtoul(next, &endptr, 10);
                if (*endptr != '\0')
                        p[n] = 0;
                if (++n == nitems(p))
                        break;
        }

        /*
         * Add terminal features. We add DECSLRM and DECFRA for some
         * identification codes here, notably 64 will catch VT520, even though
         * we can't use level 5 from DA because of VTE.
         */
        switch (p[0]) {
        case 'M': /* mintty */
                tty_default_features(features, "mintty", 0);
                break;
        case 'T': /* tmux */
                tty_default_features(features, "tmux", 0);
                break;
        case 'U': /* rxvt-unicode */
                tty_default_features(features, "rxvt-unicode", 0);
                break;
        }
        log_debug("%s: received secondary DA %.*s", c->name, (int)*size, buf);

        tty_update_features(tty);
        tty->flags |= TTY_HAVEDA2;

        return (0);
}

/*
 * Handle extended device attributes input. Returns 0 for success, -1 for
 * failure, 1 for partial.
 */
static int
tty_keys_extended_device_attributes(struct tty *tty, const char *buf,
    size_t len, size_t *size)
{
        struct client   *c = tty->client;
        int             *features = &c->term_features;
        u_int            i;
        char             tmp[128];

        *size = 0;
        if (tty->flags & TTY_HAVEXDA)
                return (-1);

        /* First four bytes are always \033P>|. */
        if (buf[0] != '\033')
                return (-1);
        if (len == 1)
                return (1);
        if (buf[1] != 'P')
                return (-1);
        if (len == 2)
                return (1);
        if (buf[2] != '>')
                return (-1);
        if (len == 3)
                return (1);
        if (buf[3] != '|')
                return (-1);
        if (len == 4)
                return (1);

        /* Copy the rest up to \033\. */
        for (i = 0; i < (sizeof tmp) - 1; i++) {
                if (4 + i == len)
                        return (1);
                if (buf[4 + i - 1] == '\033' && buf[4 + i] == '\\')
                        break;
                tmp[i] = buf[4 + i];
        }
        if (i == (sizeof tmp) - 1)
                return (-1);
        *size = 5 + i;
        if (i == 0)
                return (0);
        tmp[i - 1] = '\0';

        /* Add terminal features. */
        if (strncmp(tmp, "iTerm2 ", 7) == 0)
                tty_default_features(features, "iTerm2", 0);
        else if (strncmp(tmp, "tmux ", 5) == 0)
                tty_default_features(features, "tmux", 0);
        else if (strncmp(tmp, "XTerm(", 6) == 0)
                tty_default_features(features, "XTerm", 0);
        else if (strncmp(tmp, "mintty ", 7) == 0)
                tty_default_features(features, "mintty", 0);
        else if (strncmp(tmp, "foot(", 5) == 0)
                tty_default_features(features, "foot", 0);
        log_debug("%s: received extended DA %.*s", c->name, (int)*size, buf);

        free(c->term_type);
        c->term_type = xstrdup(tmp);

        tty_update_features(tty);
        tty->flags |= TTY_HAVEXDA;

        return (0);
}

/*
 * Handle foreground or background input. Returns 0 for success, -1 for
 * failure, 1 for partial.
 */
int
tty_keys_colours(struct tty *tty, const char *buf, size_t len, size_t *size,
    int *fg, int *bg)
{
        struct client   *c = tty->client;
        u_int            i;
        char             tmp[128];
        int              n;

        *size = 0;

        /* First four bytes are always \033]1 and 0 or 1 and ;. */
        if (buf[0] != '\033')
                return (-1);
        if (len == 1)
                return (1);
        if (buf[1] != ']')
                return (-1);
        if (len == 2)
                return (1);
        if (buf[2] != '1')
                return (-1);
        if (len == 3)
                return (1);
        if (buf[3] != '0' && buf[3] != '1')
                return (-1);
        if (len == 4)
                return (1);
        if (buf[4] != ';')
                return (-1);
        if (len == 5)
                return (1);

        /* Copy the rest up to \033\ or \007. */
        for (i = 0; i < (sizeof tmp) - 1; i++) {
                if (5 + i == len)
                        return (1);
                if (buf[5 + i - 1] == '\033' && buf[5 + i] == '\\')
                        break;
                if (buf[5 + i] == '\007')
                        break;
                tmp[i] = buf[5 + i];
        }
        if (i == (sizeof tmp) - 1)
                return (-1);
        *size = 6 + i;
        if (i == 0)
                return (0);
        if (tmp[i - 1] == '\033')
                tmp[i - 1] = '\0';
        else
                tmp[i] = '\0';

        /* Work out the colour. */
        n = colour_parseX11(tmp);
        if (n != -1 && buf[3] == '0') {
                if (c != NULL)
                        log_debug("%s fg is %s", c->name, colour_tostring(n));
                else
                        log_debug("fg is %s", colour_tostring(n));
                *fg = n;
                tty->flags &= ~TTY_WAITFG;
        } else if (n != -1) {
                if (c != NULL)
                        log_debug("%s bg is %s", c->name, colour_tostring(n));
                else
                        log_debug("bg is %s", colour_tostring(n));
                *bg = n;
                tty->flags &= ~TTY_WAITBG;
        }

        return (0);
}

/* Handle OSC 4 palette colour responses. */
static int
tty_keys_palette(struct tty *tty, const char *buf, size_t len, size_t *size)
{
        struct client                    *c = tty->client;
        u_int                             i;
        char                              tmp[128], *endptr;
        int                               idx;
        struct input_request_palette_data pd;

        *size = 0;

        /* First three bytes are always \033]4. */
        if (buf[0] != '\033')
                return (-1);
        if (len == 1)
                return (1);
        if (buf[1] != ']')
                return (-1);
        if (len == 2)
                return (1);
        if (buf[2] != '4')
                return (-1);
        if (len == 3)
                return (1);
        if (buf[3] != ';')
                return (-1);
        if (len == 4)
                return (1);

        /* Copy the rest up to \033\ or \007. */
        for (i = 0; i < (sizeof tmp) - 1; i++) {
                if (4 + i == len)
                        return (1);
                if (buf[4 + i - 1] == '\033' && buf[4 + i] == '\\')
                        break;
                if (buf[4 + i] == '\007')
                        break;
                tmp[i] = buf[4 + i];
        }
        if (i == (sizeof tmp) - 1)
                return (-1);
        *size = 5 + i;
        if (i == 0)
                return (0);
        if (tmp[i - 1] == '\033')
                tmp[i - 1] = '\0';
        else
                tmp[i] = '\0';

        /* Parse index. */
        idx = strtol(tmp, &endptr, 10);
        if (*endptr != ';')
                return (-1);
        if (idx < 0 || idx > 255)
                return (-1);

        /* Work out the colour. */
        pd.c = colour_parseX11(endptr + 1);
        if (pd.c == -1)
                return (0);
        pd.idx = idx;
        input_request_reply(c, INPUT_REQUEST_PALETTE, &pd);

        return (0);
}