/* $OpenBSD: server-client.c,v 1.452 2026/04/04 17:13:07 nicm Exp $ */

/*
 * Copyright (c) 2009 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/ioctl.h>
#include <sys/uio.h>

#include <errno.h>
#include <event.h>
#include <fcntl.h>
#include <imsg.h>
#include <paths.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <vis.h>

#include "tmux.h"

static void     server_client_free(int, short, void *);
static void     server_client_check_pane_resize(struct window_pane *);
static void     server_client_check_pane_buffer(struct window_pane *);
static void     server_client_check_window_resize(struct window *);
static key_code server_client_check_mouse(struct client *, struct key_event *);
static void     server_client_repeat_timer(int, short, void *);
static void     server_client_click_timer(int, short, void *);
static void     server_client_check_exit(struct client *);
static void     server_client_check_redraw(struct client *);
static void     server_client_check_modes(struct client *);
static void     server_client_set_title(struct client *);
static void     server_client_set_path(struct client *);
static void     server_client_reset_state(struct client *);
static void     server_client_update_latest(struct client *);
static void     server_client_dispatch(struct imsg *, void *);
static int      server_client_dispatch_command(struct client *, struct imsg *);
static int      server_client_dispatch_identify(struct client *, struct imsg *);
static int      server_client_dispatch_shell(struct client *);
static void     server_client_report_theme(struct client *, enum client_theme);

/* Compare client windows. */
static int
server_client_window_cmp(struct client_window *cw1,
    struct client_window *cw2)
{
        if (cw1->window < cw2->window)
                return (-1);
        if (cw1->window > cw2->window)
                return (1);
        return (0);
}
RB_GENERATE(client_windows, client_window, entry, server_client_window_cmp);

/* Number of attached clients. */
u_int
server_client_how_many(void)
{
        struct client   *c;
        u_int            n;

        n = 0;
        TAILQ_FOREACH(c, &clients, entry) {
                if (c->session != NULL && (~c->flags & CLIENT_UNATTACHEDFLAGS))
                        n++;
        }
        return (n);
}

/* Overlay timer callback. */
static void
server_client_overlay_timer(__unused int fd, __unused short events, void *data)
{
        server_client_clear_overlay(data);
}

/* Set an overlay on client. */
void
server_client_set_overlay(struct client *c, u_int delay,
    overlay_check_cb checkcb, overlay_mode_cb modecb,
    overlay_draw_cb drawcb, overlay_key_cb keycb, overlay_free_cb freecb,
    overlay_resize_cb resizecb, void *data)
{
        struct timeval  tv;

        if (c->overlay_draw != NULL)
                server_client_clear_overlay(c);

        tv.tv_sec = delay / 1000;
        tv.tv_usec = (delay % 1000) * 1000L;

        if (event_initialized(&c->overlay_timer))
                evtimer_del(&c->overlay_timer);
        evtimer_set(&c->overlay_timer, server_client_overlay_timer, c);
        if (delay != 0)
                evtimer_add(&c->overlay_timer, &tv);

        c->overlay_check = checkcb;
        c->overlay_mode = modecb;
        c->overlay_draw = drawcb;
        c->overlay_key = keycb;
        c->overlay_free = freecb;
        c->overlay_resize = resizecb;
        c->overlay_data = data;

        if (c->overlay_check == NULL)
                c->tty.flags |= TTY_FREEZE;
        if (c->overlay_mode == NULL)
                c->tty.flags |= TTY_NOCURSOR;
        window_update_focus(c->session->curw->window);
        server_redraw_client(c);
}

/* Clear overlay mode on client. */
void
server_client_clear_overlay(struct client *c)
{
        if (c->overlay_draw == NULL)
                return;

        if (event_initialized(&c->overlay_timer))
                evtimer_del(&c->overlay_timer);

        if (c->overlay_free != NULL)
                c->overlay_free(c, c->overlay_data);

        c->overlay_check = NULL;
        c->overlay_mode = NULL;
        c->overlay_draw = NULL;
        c->overlay_key = NULL;
        c->overlay_free = NULL;
        c->overlay_resize = NULL;
        c->overlay_data = NULL;

        c->tty.flags &= ~(TTY_FREEZE|TTY_NOCURSOR);
        if (c->session != NULL)
                window_update_focus(c->session->curw->window);
        server_redraw_client(c);
}

/* Are these ranges empty? That is, nothing is visible. */
int
server_client_ranges_is_empty(struct visible_ranges *r)
{
        u_int   i;

        for (i = 0; i < r->used; i++) {
                if (r->ranges[i].nx != 0)
                        return (0);
        }
        return (1);
}

/* Ensure we have space for at least n ranges. */
void
server_client_ensure_ranges(struct visible_ranges *r, u_int n)
{
        if (r->size >= n)
                return;
        r->ranges = xrecallocarray(r->ranges, r->size, n, sizeof *r->ranges);
        r->size = n;
}

/*
 * Given overlay position and dimensions, return parts of the input range which
 * are visible.
 */
void
server_client_overlay_range(u_int x, u_int y, u_int sx, u_int sy, u_int px,
    u_int py, u_int nx, struct visible_ranges *r)
{
        u_int   ox, onx;

        /* Trivial case of no overlap in the y direction. */
        if (py < y || py > y + sy - 1) {
                server_client_ensure_ranges(r, 1);
                r->ranges[0].px = px;
                r->ranges[0].nx = nx;
                r->used = 1;
                return;
        }
        server_client_ensure_ranges(r, 2);

        /* Visible bit to the left of the popup. */
        if (px < x) {
                r->ranges[0].px = px;
                r->ranges[0].nx = x - px;
                if (r->ranges[0].nx > nx)
                        r->ranges[0].nx = nx;
        } else {
                r->ranges[0].px = 0;
                r->ranges[0].nx = 0;
        }

        /* Visible bit to the right of the popup. */
        ox = x + sx;
        if (px > ox)
                ox = px;
        onx = px + nx;
        if (onx > ox) {
                r->ranges[1].px = ox;
                r->ranges[1].nx = onx - ox;
        } else {
                r->ranges[1].px = 0;
                r->ranges[1].nx = 0;
        }
        r->used = 2;
}

/* Check if this client is inside this server. */
int
server_client_check_nested(struct client *c)
{
        struct environ_entry    *envent;
        struct window_pane      *wp;

        envent = environ_find(c->environ, "TMUX");
        if (envent == NULL || *envent->value == '\0')
                return (0);

        RB_FOREACH(wp, window_pane_tree, &all_window_panes) {
                if (strcmp(wp->tty, c->ttyname) == 0)
                        return (1);
        }
        return (0);
}

/* Set client key table. */
void
server_client_set_key_table(struct client *c, const char *name)
{
        if (name == NULL)
                name = server_client_get_key_table(c);

        key_bindings_unref_table(c->keytable);
        c->keytable = key_bindings_get_table(name, 1);
        c->keytable->references++;
        if (gettimeofday(&c->keytable->activity_time, NULL) != 0)
                fatal("gettimeofday failed");
}

static uint64_t
server_client_key_table_activity_diff(struct client *c)
{
        struct timeval  diff;

        timersub(&c->activity_time, &c->keytable->activity_time, &diff);
        return ((diff.tv_sec * 1000ULL) + (diff.tv_usec / 1000ULL));
}

/* Get default key table. */
const char *
server_client_get_key_table(struct client *c)
{
        struct session  *s = c->session;
        const char      *name;

        if (s == NULL)
                return ("root");

        name = options_get_string(s->options, "key-table");
        if (*name == '\0')
                return ("root");
        return (name);
}

/* Is this table the default key table? */
static int
server_client_is_default_key_table(struct client *c, struct key_table *table)
{
        return (strcmp(table->name, server_client_get_key_table(c)) == 0);
}

/* Create a new client. */
struct client *
server_client_create(int fd)
{
        struct client   *c;

        setblocking(fd, 0);

        c = xcalloc(1, sizeof *c);
        c->references = 1;
        c->peer = proc_add_peer(server_proc, fd, server_client_dispatch, c);

        if (gettimeofday(&c->creation_time, NULL) != 0)
                fatal("gettimeofday failed");
        memcpy(&c->activity_time, &c->creation_time, sizeof c->activity_time);

        c->environ = environ_create();

        c->fd = -1;
        c->out_fd = -1;

        c->queue = cmdq_new();
        RB_INIT(&c->windows);
        RB_INIT(&c->files);

        c->tty.sx = 80;
        c->tty.sy = 24;
        c->theme = THEME_UNKNOWN;

        status_init(c);
        c->flags |= CLIENT_FOCUSED;

        c->keytable = key_bindings_get_table("root", 1);
        c->keytable->references++;

        evtimer_set(&c->repeat_timer, server_client_repeat_timer, c);
        evtimer_set(&c->click_timer, server_client_click_timer, c);

        c->click_wp = -1;

        TAILQ_INIT(&c->input_requests);

        TAILQ_INSERT_TAIL(&clients, c, entry);
        log_debug("new client %p", c);
        return (c);
}

/* Open client terminal if needed. */
int
server_client_open(struct client *c, char **cause)
{
        const char      *ttynam = _PATH_TTY;

        if (c->flags & CLIENT_CONTROL)
                return (0);

        if (strcmp(c->ttyname, ttynam) == 0||
            ((isatty(STDIN_FILENO) &&
            (ttynam = ttyname(STDIN_FILENO)) != NULL &&
            strcmp(c->ttyname, ttynam) == 0) ||
            (isatty(STDOUT_FILENO) &&
            (ttynam = ttyname(STDOUT_FILENO)) != NULL &&
            strcmp(c->ttyname, ttynam) == 0) ||
            (isatty(STDERR_FILENO) &&
            (ttynam = ttyname(STDERR_FILENO)) != NULL &&
            strcmp(c->ttyname, ttynam) == 0))) {
                xasprintf(cause, "can't use %s", c->ttyname);
                return (-1);
        }

        if (!(c->flags & CLIENT_TERMINAL)) {
                *cause = xstrdup("not a terminal");
                return (-1);
        }

        if (tty_open(&c->tty, cause) != 0)
                return (-1);

        return (0);
}

/* Lost an attached client. */
static void
server_client_attached_lost(struct client *c)
{
        struct session  *s;
        struct window   *w;
        struct client   *loop;
        struct client   *found;

        log_debug("lost attached client %p", c);

        /*
         * By this point the session in the client has been cleared so walk all
         * windows to find any with this client as the latest.
         */
        RB_FOREACH(w, windows, &windows) {
                if (w->latest != c)
                        continue;

                found = NULL;
                TAILQ_FOREACH(loop, &clients, entry) {
                        s = loop->session;
                        if (loop == c || s == NULL || s->curw->window != w)
                                continue;
                        if (found == NULL || timercmp(&loop->activity_time,
                            &found->activity_time, >))
                                found = loop;
                }
                if (found != NULL)
                        server_client_update_latest(found);
        }
}

/* Set client session. */
void
server_client_set_session(struct client *c, struct session *s)
{
        struct session  *old = c->session;

        if (s != NULL && c->session != NULL && c->session != s)
                c->last_session = c->session;
        else if (s == NULL)
                c->last_session = NULL;
        c->session = s;
        c->flags |= CLIENT_FOCUSED;

        if (old != NULL && old->curw != NULL)
                window_update_focus(old->curw->window);
        if (s != NULL) {
                s->curw->window->latest = c;
                recalculate_sizes();
                window_update_focus(s->curw->window);
                session_update_activity(s, NULL);
                session_theme_changed(s);
                gettimeofday(&s->last_attached_time, NULL);
                s->curw->flags &= ~WINLINK_ALERTFLAGS;
                alerts_check_session(s);
                tty_update_client_offset(c);
                status_timer_start(c);
                notify_client("client-session-changed", c);
                server_redraw_client(c);
        }

        server_check_unattached();
        server_update_socket();
}

/* Lost a client. */
void
server_client_lost(struct client *c)
{
        struct client_file      *cf, *cf1;
        struct client_window    *cw, *cw1;

        c->flags |= CLIENT_DEAD;

        server_client_clear_overlay(c);
        status_prompt_clear(c);
        status_message_clear(c);

        RB_FOREACH_SAFE(cf, client_files, &c->files, cf1) {
                cf->error = EINTR;
                file_fire_done(cf);
        }
        RB_FOREACH_SAFE(cw, client_windows, &c->windows, cw1) {
                RB_REMOVE(client_windows, &c->windows, cw);
                free(cw);
        }

        TAILQ_REMOVE(&clients, c, entry);
        log_debug("lost client %p", c);

        if (c->flags & CLIENT_ATTACHED) {
                server_client_attached_lost(c);
                notify_client("client-detached", c);
        }

        if (c->flags & CLIENT_CONTROL)
                control_stop(c);
        if (c->flags & CLIENT_TERMINAL)
                tty_free(&c->tty);
        free(c->ttyname);
        free(c->clipboard_panes);

        free(c->term_name);
        free(c->term_type);
        tty_term_free_list(c->term_caps, c->term_ncaps);

        status_free(c);
        input_cancel_requests(c);

        free(c->title);
        free((void *)c->cwd);

        evtimer_del(&c->repeat_timer);
        evtimer_del(&c->click_timer);

        key_bindings_unref_table(c->keytable);

        free(c->message_string);
        if (event_initialized(&c->message_timer))
                evtimer_del(&c->message_timer);

        free(c->prompt_saved);
        free(c->prompt_string);
        free(c->prompt_buffer);

        format_lost_client(c);
        environ_free(c->environ);

        proc_remove_peer(c->peer);
        c->peer = NULL;

        if (c->out_fd != -1)
                close(c->out_fd);
        if (c->fd != -1) {
                close(c->fd);
                c->fd = -1;
        }
        server_client_unref(c);

        server_add_accept(0); /* may be more file descriptors now */

        recalculate_sizes();
        server_check_unattached();
        server_update_socket();
}

/* Remove reference from a client. */
void
server_client_unref(struct client *c)
{
        log_debug("unref client %p (%d references)", c, c->references);

        c->references--;
        if (c->references == 0)
                event_once(-1, EV_TIMEOUT, server_client_free, c, NULL);
}

/* Free dead client. */
static void
server_client_free(__unused int fd, __unused short events, void *arg)
{
        struct client   *c = arg;

        log_debug("free client %p (%d references)", c, c->references);

        cmdq_free(c->queue);

        if (c->references == 0) {
                free((void *)c->name);
                free((void *)c->user);
                free(c);
        }
}

/* Suspend a client. */
void
server_client_suspend(struct client *c)
{
        struct session  *s = c->session;

        if (s == NULL || (c->flags & CLIENT_UNATTACHEDFLAGS))
                return;

        tty_stop_tty(&c->tty);
        c->flags |= CLIENT_SUSPENDED;
        proc_send(c->peer, MSG_SUSPEND, -1, NULL, 0);
}

/* Detach a client. */
void
server_client_detach(struct client *c, enum msgtype msgtype)
{
        struct session  *s = c->session;

        if (s == NULL || (c->flags & CLIENT_NODETACHFLAGS))
                return;

        c->flags |= CLIENT_EXIT;

        c->exit_type = CLIENT_EXIT_DETACH;
        c->exit_msgtype = msgtype;
        c->exit_session = xstrdup(s->name);
}

/* Execute command to replace a client. */
void
server_client_exec(struct client *c, const char *cmd)
{
        struct session  *s = c->session;
        char            *msg;
        const char      *shell;
        size_t           cmdsize, shellsize;

        if (*cmd == '\0')
                return;
        cmdsize = strlen(cmd) + 1;

        if (s != NULL)
                shell = options_get_string(s->options, "default-shell");
        else
                shell = options_get_string(global_s_options, "default-shell");
        if (!checkshell(shell))
                shell = _PATH_BSHELL;
        shellsize = strlen(shell) + 1;

        msg = xmalloc(cmdsize + shellsize);
        memcpy(msg, cmd, cmdsize);
        memcpy(msg + cmdsize, shell, shellsize);

        proc_send(c->peer, MSG_EXEC, -1, msg, cmdsize + shellsize);
        free(msg);
}

static enum key_code_mouse_location
server_client_check_mouse_in_pane(struct window_pane *wp, u_int px, u_int py,
    u_int *sl_mpos)
{
        struct window           *w = wp->window;
        struct options          *wo = w->options;
        struct window_pane      *fwp;
        int                      pane_status, sb, sb_pos, sb_w, sb_pad;
        int                      pane_status_line, sl_top, sl_bottom;
        int                      bdr_bottom, bdr_top, bdr_right;

        sb = options_get_number(wo, "pane-scrollbars");
        sb_pos = options_get_number(wo, "pane-scrollbars-position");
        pane_status = options_get_number(wo, "pane-border-status");

        if (window_pane_show_scrollbar(wp, sb)) {
                sb_w = wp->scrollbar_style.width;
                sb_pad = wp->scrollbar_style.pad;
        } else {
                sb_w = 0;
                sb_pad = 0;
        }

        if (pane_status == PANE_STATUS_TOP)
                pane_status_line = wp->yoff - 1;
        else if (pane_status == PANE_STATUS_BOTTOM)
                pane_status_line = wp->yoff + wp->sy;
        else
                pane_status_line = -1; /* not used */

        /* Check if point is within the pane or scrollbar. */
        if (((pane_status != PANE_STATUS_OFF &&
            (int)py != pane_status_line && py != wp->yoff + wp->sy) ||
            (wp->yoff == 0 && py < wp->sy) ||
            (py >= wp->yoff && py < wp->yoff + wp->sy)) &&
            ((sb_pos == PANE_SCROLLBARS_RIGHT &&
            (int)px < (int)wp->xoff + (int)wp->sx + sb_pad + sb_w) ||
            (sb_pos == PANE_SCROLLBARS_LEFT &&
            (int)px < (int)wp->xoff + (int)wp->sx - sb_pad - sb_w))) {
                /* Check if in the scrollbar. */
                if ((sb_pos == PANE_SCROLLBARS_RIGHT &&
                    ((int)px >= (int)wp->xoff + (int)wp->sx + sb_pad &&
                    (int)px < (int)wp->xoff + (int)wp->sx + sb_pad + sb_w)) ||
                    (sb_pos == PANE_SCROLLBARS_LEFT &&
                    ((int)px >= (int)wp->xoff - sb_pad - sb_w &&
                    (int)px < (int)wp->xoff - sb_pad))) {
                        /* Check where inside the scrollbar. */
                        sl_top = wp->yoff + wp->sb_slider_y;
                        sl_bottom = (wp->yoff + wp->sb_slider_y +
                            wp->sb_slider_h - 1);
                        if ((int)py < sl_top)
                                return (KEYC_MOUSE_LOCATION_SCROLLBAR_UP);
                        else if ((int)py >= sl_top &&
                                 (int)py <= sl_bottom) {
                                *sl_mpos = (py - wp->sb_slider_y - wp->yoff);
                                return (KEYC_MOUSE_LOCATION_SCROLLBAR_SLIDER);
                        } else /* py > sl_bottom */
                                return (KEYC_MOUSE_LOCATION_SCROLLBAR_DOWN);
                } else {
                        /* Must be inside the pane. */
                        return (KEYC_MOUSE_LOCATION_PANE);
                }
        } else {
                /* Try the pane borders. */
                TAILQ_FOREACH(fwp, &w->panes, entry) {
                        if ((w->flags & WINDOW_ZOOMED) &&
                            (~fwp->flags & PANE_ZOOMED))
                                continue;
                        bdr_top = fwp->yoff - 1;
                        bdr_bottom = fwp->yoff + (int)fwp->sy;
                        if (sb_pos == PANE_SCROLLBARS_LEFT)
                                bdr_right = fwp->xoff + (int)fwp->sx;
                        else
                                /* PANE_SCROLLBARS_RIGHT or none. */
                                bdr_right = fwp->xoff + (int)fwp->sx +
                                    sb_pad + sb_w;
                        if ((int)py >= (int)fwp->yoff - 1 &&
                            py <= fwp->yoff + fwp->sy) {
                                if ((int)px == bdr_right)
                                        break;
                        }
                        if ((int)px >= (int)fwp->xoff - 1 &&
                            px <= fwp->xoff + fwp->sx) {
                                if ((int)py == bdr_bottom || (int)py == bdr_top)
                                        break;
                        }
                }
                if (fwp != NULL)
                        return (KEYC_MOUSE_LOCATION_BORDER);
        }
        return (KEYC_MOUSE_LOCATION_NOWHERE);
}

/* Check for mouse keys. */
static key_code
server_client_check_mouse(struct client *c, struct key_event *event)
{
        struct mouse_event              *m = &event->m;
        struct session                  *s = c->session, *fs;
        struct window                   *w = s->curw->window;
        struct winlink                  *fwl;
        struct window_pane              *wp, *fwp;
        u_int                            x, y, sx, sy, px, py, n, sl_mpos = 0;
        u_int                            b, bn;
        int                              ignore = 0;
        key_code                         key;
        struct timeval                   tv;
        struct style_range              *sr;
        enum key_code_type               type = KEYC_TYPE_NOTYPE;
        enum key_code_mouse_location     loc = KEYC_MOUSE_LOCATION_NOWHERE;

        log_debug("%s mouse %02x at %u,%u (last %u,%u) (%d)", c->name, m->b,
            m->x, m->y, m->lx, m->ly, c->tty.mouse_drag_flag);

        /* What type of event is this? */
        if (event->key == KEYC_DOUBLECLICK) {
                type = KEYC_TYPE_DOUBLECLICK;
                x = m->x, y = m->y, b = m->b;
                ignore = 1;
                log_debug("double-click at %u,%u", x, y);
        } else if ((m->sgr_type != ' ' &&
            MOUSE_DRAG(m->sgr_b) &&
            MOUSE_RELEASE(m->sgr_b)) ||
            (m->sgr_type == ' ' &&
            MOUSE_DRAG(m->b) &&
            MOUSE_RELEASE(m->b) &&
            MOUSE_RELEASE(m->lb))) {
                type = KEYC_TYPE_MOUSEMOVE;
                x = m->x, y = m->y, b = 0;
                log_debug("move at %u,%u", x, y);
        } else if (MOUSE_DRAG(m->b)) {
                type = KEYC_TYPE_MOUSEDRAG;
                if (c->tty.mouse_drag_flag) {
                        x = m->x, y = m->y, b = m->b;
                        if (x == m->lx && y == m->ly)
                                return (KEYC_UNKNOWN);
                        log_debug("drag update at %u,%u", x, y);
                } else {
                        x = m->lx, y = m->ly, b = m->lb;
                        log_debug("drag start at %u,%u", x, y);
                }
        } else if (MOUSE_WHEEL(m->b)) {
                if ((m->b & MOUSE_MASK_BUTTONS) == MOUSE_WHEEL_UP)
                        type = KEYC_TYPE_WHEELUP;
                else
                        type = KEYC_TYPE_WHEELDOWN;
                x = m->x, y = m->y, b = m->b;
                log_debug("wheel at %u,%u", x, y);
        } else if (MOUSE_RELEASE(m->b)) {
                type = KEYC_TYPE_MOUSEUP;
                x = m->x, y = m->y, b = m->lb;
                if (m->sgr_type == 'm')
                        b = m->sgr_b;
                log_debug("up at %u,%u", x, y);
        } else {
                if (c->flags & CLIENT_DOUBLECLICK) {
                        evtimer_del(&c->click_timer);
                        c->flags &= ~CLIENT_DOUBLECLICK;
                        type = KEYC_TYPE_SECONDCLICK;
                        x = m->x, y = m->y, b = m->b;
                        log_debug("second-click at %u,%u", x, y);
                        c->flags |= CLIENT_TRIPLECLICK;
                } else if (c->flags & CLIENT_TRIPLECLICK) {
                        evtimer_del(&c->click_timer);
                        c->flags &= ~CLIENT_TRIPLECLICK;
                        type = KEYC_TYPE_TRIPLECLICK;
                        x = m->x, y = m->y, b = m->b;
                        log_debug("triple-click at %u,%u", x, y);
                        goto have_event;
                }

                /* DOWN is the only remaining event type. */
                if (type == KEYC_TYPE_NOTYPE) {
                        type = KEYC_TYPE_MOUSEDOWN;
                        x = m->x, y = m->y, b = m->b;
                        log_debug("down at %u,%u", x, y);
                        c->flags |= CLIENT_DOUBLECLICK;
                }
        }

have_event:
        if (type == KEYC_TYPE_NOTYPE)
                return (KEYC_UNKNOWN);

        /* Save the session. */
        m->s = s->id;
        m->w = -1;
        m->wp = -1;
        m->ignore = ignore;

        /* Is this on the status line? */
        m->statusat = status_at_line(c);
        m->statuslines = status_line_size(c);
        if (m->statusat != -1 &&
            y >= (u_int)m->statusat &&
            y < m->statusat + m->statuslines) {
                sr = status_get_range(c, x, y - m->statusat);
                if (sr == NULL) {
                        loc = KEYC_MOUSE_LOCATION_STATUS_DEFAULT;
                } else {
                        switch (sr->type) {
                        case STYLE_RANGE_NONE:
                                return (KEYC_UNKNOWN);
                        case STYLE_RANGE_LEFT:
                                log_debug("mouse range: left");
                                loc = KEYC_MOUSE_LOCATION_STATUS_LEFT;
                                break;
                        case STYLE_RANGE_RIGHT:
                                log_debug("mouse range: right");
                                loc = KEYC_MOUSE_LOCATION_STATUS_RIGHT;
                                break;
                        case STYLE_RANGE_PANE:
                                fwp = window_pane_find_by_id(sr->argument);
                                if (fwp == NULL)
                                        return (KEYC_UNKNOWN);
                                m->wp = sr->argument;

                                log_debug("mouse range: pane %%%u", m->wp);
                                loc = KEYC_MOUSE_LOCATION_STATUS;
                                break;
                        case STYLE_RANGE_WINDOW:
                                fwl = winlink_find_by_index(&s->windows,
                                    sr->argument);
                                if (fwl == NULL)
                                        return (KEYC_UNKNOWN);
                                m->w = fwl->window->id;

                                log_debug("mouse range: window @%u", m->w);
                                loc = KEYC_MOUSE_LOCATION_STATUS;
                                break;
                        case STYLE_RANGE_SESSION:
                                fs = session_find_by_id(sr->argument);
                                if (fs == NULL)
                                        return (KEYC_UNKNOWN);
                                m->s = sr->argument;

                                log_debug("mouse range: session $%u", m->s);
                                loc = KEYC_MOUSE_LOCATION_STATUS;
                                break;
                        case STYLE_RANGE_USER:
                                log_debug("mouse range: user");
                                loc = KEYC_MOUSE_LOCATION_STATUS;
                                break;
                        case STYLE_RANGE_CONTROL:
                                n = sr->argument; /* parsing keeps this < 10 */
                                log_debug("mouse range: control %u", n);
                                loc = KEYC_MOUSE_LOCATION_CONTROL0 + n;
                                break;
                        }
                }
        }

        /*
         * Not on status line. Adjust position and check for border, pane, or
         * scrollbar.
         */
        if (loc == KEYC_MOUSE_LOCATION_NOWHERE) {
                if (c->tty.mouse_scrolling_flag)
                        loc = KEYC_MOUSE_LOCATION_SCROLLBAR_SLIDER;
                else {
                        px = x;
                        if (m->statusat == 0 && y >= m->statuslines)
                                py = y - m->statuslines;
                        else if (m->statusat > 0 && y >= (u_int)m->statusat)
                                py = m->statusat - 1;
                        else
                                py = y;

                        tty_window_offset(&c->tty, &m->ox, &m->oy, &sx, &sy);
                        log_debug("mouse window @%u at %u,%u (%ux%u)",
                                  w->id, m->ox, m->oy, sx, sy);
                        if (px > sx || py > sy)
                                return (KEYC_UNKNOWN);
                        px = px + m->ox;
                        py = py + m->oy;

                        /* Try inside the pane. */
                        wp = window_get_active_at(w, px, py);
                        if (wp == NULL)
                                return (KEYC_UNKNOWN);
                        loc = server_client_check_mouse_in_pane(wp, px, py,
                            &sl_mpos);

                        if (loc == KEYC_MOUSE_LOCATION_PANE) {
                                log_debug("mouse %u,%u on pane %%%u", x, y,
                                    wp->id);
                        } else if (loc == KEYC_MOUSE_LOCATION_BORDER) {
                                sr = window_pane_border_status_get_range(wp, px,
                                        py);
                                if (sr != NULL) {
                                        n = sr->argument;
                                        loc = KEYC_MOUSE_LOCATION_CONTROL0 + n;
                                }
                                log_debug("mouse on pane %%%u border", wp->id);
                        } else if (loc == KEYC_MOUSE_LOCATION_SCROLLBAR_UP ||
                            loc == KEYC_MOUSE_LOCATION_SCROLLBAR_SLIDER ||
                            loc == KEYC_MOUSE_LOCATION_SCROLLBAR_DOWN) {
                                log_debug("mouse on pane %%%u scrollbar",
                                    wp->id);
                        }
                        m->wp = wp->id;
                        m->w = wp->window->id;
                }
        }

        /* Reset click type or add a click timer if needed. */
        if (type == KEYC_TYPE_MOUSEDOWN ||
            type == KEYC_TYPE_SECONDCLICK ||
            type == KEYC_TYPE_TRIPLECLICK) {
                if (type != KEYC_TYPE_MOUSEDOWN &&
                    (m->b != c->click_button ||
                    loc != (enum key_code_mouse_location)c->click_loc ||
                    m->wp != c->click_wp)) {
                        type = KEYC_TYPE_MOUSEDOWN;
                        log_debug("click sequence reset at %u,%u", x, y);
                        c->flags &= ~CLIENT_TRIPLECLICK;
                        c->flags |= CLIENT_DOUBLECLICK;
                }

                if (type != KEYC_TYPE_TRIPLECLICK && KEYC_CLICK_TIMEOUT != 0) {
                        memcpy(&c->click_event, m, sizeof c->click_event);
                        c->click_button = m->b;
                        c->click_loc = loc;
                        c->click_wp = m->wp;

                        log_debug("click timer started");
                        tv.tv_sec = KEYC_CLICK_TIMEOUT / 1000;
                        tv.tv_usec = (KEYC_CLICK_TIMEOUT % 1000) * 1000L;
                        evtimer_del(&c->click_timer);
                        evtimer_add(&c->click_timer, &tv);
                }
        }

        key = KEYC_UNKNOWN;

        /* Stop dragging if needed. */
        if (type != KEYC_TYPE_MOUSEDRAG &&
            type != KEYC_TYPE_WHEELUP &&
            type != KEYC_TYPE_WHEELDOWN &&
            type != KEYC_TYPE_DOUBLECLICK &&
            type != KEYC_TYPE_TRIPLECLICK &&
            c->tty.mouse_drag_flag != 0) {
                if (c->tty.mouse_drag_release != NULL)
                        c->tty.mouse_drag_release(c, m);

                c->tty.mouse_drag_update = NULL;
                c->tty.mouse_drag_release = NULL;
                c->tty.mouse_scrolling_flag = 0;

                /*
                 * End a mouse drag by passing a MouseDragEnd key corresponding
                 * to the button that started the drag.
                 */
                type = KEYC_TYPE_MOUSEDRAGEND;
                c->tty.mouse_drag_flag = 0;
                c->tty.mouse_slider_mpos = -1;
        }

        /* Convert to a key binding. */
        if (type == KEYC_TYPE_MOUSEMOVE && loc == KEYC_MOUSE_LOCATION_PANE) {
                key = KEYC_MOUSEMOVE_PANE;
                if (wp != NULL &&
                    wp != w->active &&
                    options_get_number(s->options, "focus-follows-mouse")) {
                        window_set_active_pane(w, wp, 1);
                        server_redraw_window_borders(w);
                        server_status_window(w);
                }
        }
        if (type == KEYC_TYPE_MOUSEDRAG) {
                if (c->tty.mouse_drag_update != NULL)
                        key = KEYC_DRAGGING;

                /*
                 * Begin a drag by setting the flag to a non-zero value that
                 * corresponds to the mouse button in use. If starting to drag
                 * the scrollbar, store the relative position in the slider
                 * where the user grabbed.
                 */
                c->tty.mouse_drag_flag = MOUSE_BUTTONS(b) + 1;
                if (c->tty.mouse_scrolling_flag == 0 &&
                    loc == KEYC_MOUSE_LOCATION_SCROLLBAR_SLIDER) {
                        c->tty.mouse_scrolling_flag = 1;
                        if (m->statusat == 0) {
                                c->tty.mouse_slider_mpos = sl_mpos +
                                    m->statuslines;
                        } else
                                c->tty.mouse_slider_mpos = sl_mpos;
                }
        }

        if (key == KEYC_UNKNOWN) {
                /* Adjust the button number. */
                if (MOUSE_BUTTONS(b) == MOUSE_BUTTON_1)
                        bn = 1;
                else if (MOUSE_BUTTONS(b) == MOUSE_BUTTON_2)
                        bn = 2;
                else if (MOUSE_BUTTONS(b) == MOUSE_BUTTON_3)
                        bn = 3;
                else if (MOUSE_BUTTONS(b) == MOUSE_BUTTON_6)
                        bn = 6;
                else if (MOUSE_BUTTONS(b) == MOUSE_BUTTON_7)
                        bn = 7;
                else if (MOUSE_BUTTONS(b) == MOUSE_BUTTON_8)
                        bn = 8;
                else if (MOUSE_BUTTONS(b) == MOUSE_BUTTON_9)
                        bn = 9;
                else if (MOUSE_BUTTONS(b) == MOUSE_BUTTON_10)
                        bn = 10;
                else if (MOUSE_BUTTONS(b) == MOUSE_BUTTON_11)
                        bn = 11;
                else
                        bn = 0;
                key = KEYC_MAKE_MOUSE_KEY(type, bn, loc);
        }

        /* Apply modifiers if any. */
        if (b & MOUSE_MASK_META)
                key |= KEYC_META;
        if (b & MOUSE_MASK_CTRL)
                key |= KEYC_CTRL;
        if (b & MOUSE_MASK_SHIFT)
                key |= KEYC_SHIFT;

        if (log_get_level() != 0)
                log_debug("mouse key is %s", key_string_lookup_key (key, 1));
        return (key);
}

/* Is this a bracket paste key? */
static int
server_client_is_bracket_paste(struct client *c, key_code key)
{
        if ((key & KEYC_MASK_KEY) == KEYC_PASTE_START) {
                c->flags |= CLIENT_BRACKETPASTING;
                log_debug("%s: bracket paste on", c->name);
                return (0);
        }

        if ((key & KEYC_MASK_KEY) == KEYC_PASTE_END) {
                c->flags &= ~CLIENT_BRACKETPASTING;
                log_debug("%s: bracket paste off", c->name);
                return (0);
        }

        return !!(c->flags & CLIENT_BRACKETPASTING);
}

/* Is this fast enough to probably be a paste? */
static int
server_client_is_assume_paste(struct client *c)
{
        struct session  *s = c->session;
        struct timeval   tv;
        int              t;

        if (c->flags & CLIENT_BRACKETPASTING)
                return (0);
        if ((t = options_get_number(s->options, "assume-paste-time")) == 0)
                return (0);

        timersub(&c->activity_time, &c->last_activity_time, &tv);
        if (tv.tv_sec == 0 && tv.tv_usec < t * 1000) {
                if (c->flags & CLIENT_ASSUMEPASTING)
                        return (1);
                c->flags |= CLIENT_ASSUMEPASTING;
                log_debug("%s: assume paste on", c->name);
                return (0);
        }
        if (c->flags & CLIENT_ASSUMEPASTING) {
                c->flags &= ~CLIENT_ASSUMEPASTING;
                log_debug("%s: assume paste off", c->name);
        }
        return (0);
}

/* Has the latest client changed? */
static void
server_client_update_latest(struct client *c)
{
        struct window   *w;

        if (c->session == NULL)
                return;
        w = c->session->curw->window;

        if (w->latest == c)
                return;
        w->latest = c;

        if (options_get_number(w->options, "window-size") == WINDOW_SIZE_LATEST)
                recalculate_size(w, 0);

        notify_client("client-active", c);
}

/* Get repeat time. */
static u_int
server_client_repeat_time(struct client *c, struct key_binding *bd)
{
        struct session  *s = c->session;
        u_int            repeat, initial;

        if (~bd->flags & KEY_BINDING_REPEAT)
                return (0);
        repeat = options_get_number(s->options, "repeat-time");
        if (repeat == 0)
                return (0);
        if ((~c->flags & CLIENT_REPEAT) || bd->key != c->last_key) {
                initial = options_get_number(s->options, "initial-repeat-time");
                if (initial != 0)
                        repeat = initial;
        }
        return (repeat);
}

/*
 * Handle data key input from client. This owns and can modify the key event it
 * is given and is responsible for freeing it.
 */
static enum cmd_retval
server_client_key_callback(struct cmdq_item *item, void *data)
{
        struct client                   *c = cmdq_get_client(item);
        struct key_event                *event = data;
        key_code                         key = event->key;
        struct mouse_event              *m = &event->m;
        struct session                  *s = c->session;
        struct winlink                  *wl;
        struct window_pane              *wp;
        struct window_mode_entry        *wme;
        struct timeval                   tv;
        struct key_table                *table, *first;
        struct key_binding              *bd;
        u_int                            repeat;
        uint64_t                         flags, prefix_delay;
        struct cmd_find_state            fs;
        key_code                         key0, prefix, prefix2;

        /* Check the client is good to accept input. */
        if (s == NULL || (c->flags & CLIENT_UNATTACHEDFLAGS))
                goto out;
        wl = s->curw;

        /* Update the activity timer. */
        memcpy(&c->last_activity_time, &c->activity_time,
            sizeof c->last_activity_time);
        if (gettimeofday(&c->activity_time, NULL) != 0)
                fatal("gettimeofday failed");
        session_update_activity(s, &c->activity_time);

        /* Check for mouse keys. */
        m->valid = 0;
        if (key == KEYC_MOUSE || key == KEYC_DOUBLECLICK) {
                if (c->flags & CLIENT_READONLY)
                        goto out;
                key = server_client_check_mouse(c, event);
                if (key == KEYC_UNKNOWN)
                        goto out;

                m->valid = 1;
                m->key = key;

                /*
                 * Mouse drag is in progress, so fire the callback (now that
                 * the mouse event is valid).
                 */
                if ((key & KEYC_MASK_KEY) == KEYC_DRAGGING) {
                        c->tty.mouse_drag_update(c, m);
                        goto out;
                }
                event->key = key;
        }

        /* Find affected pane. */
        if (!KEYC_IS_MOUSE(key) || cmd_find_from_mouse(&fs, m, 0) != 0)
                cmd_find_from_client(&fs, c, 0);
        wp = fs.wp;

        /* Forward mouse keys if disabled. */
        if (KEYC_IS_MOUSE(key) && !options_get_number(s->options, "mouse"))
                goto forward_key;

        /* Forward if bracket pasting. */
        if (server_client_is_bracket_paste (c, key))
                goto paste_key;

        /* Treat everything as a regular key when pasting is detected. */
        if (!KEYC_IS_MOUSE(key) &&
            key != KEYC_FOCUS_IN &&
            key != KEYC_FOCUS_OUT &&
            (~key & KEYC_SENT) &&
            server_client_is_assume_paste(c))
                goto paste_key;

        /*
         * Work out the current key table. If the pane is in a mode, use
         * the mode table instead of the default key table.
         */
        if (server_client_is_default_key_table(c, c->keytable) &&
            wp != NULL &&
            (wme = TAILQ_FIRST(&wp->modes)) != NULL &&
            wme->mode->key_table != NULL)
                table = key_bindings_get_table(wme->mode->key_table(wme), 1);
        else
                table = c->keytable;
        first = table;

table_changed:
        /*
         * The prefix always takes precedence and forces a switch to the prefix
         * table, unless we are already there.
         */
        prefix = (key_code)options_get_number(s->options, "prefix");
        prefix2 = (key_code)options_get_number(s->options, "prefix2");
        key0 = (key & (KEYC_MASK_KEY|KEYC_MASK_MODIFIERS));
        if ((key0 == (prefix & (KEYC_MASK_KEY|KEYC_MASK_MODIFIERS)) ||
            key0 == (prefix2 & (KEYC_MASK_KEY|KEYC_MASK_MODIFIERS))) &&
            strcmp(table->name, "prefix") != 0) {
                server_client_set_key_table(c, "prefix");
                server_status_client(c);
                goto out;
        }
        flags = c->flags;

try_again:
        /* Log key table. */
        if (wp == NULL)
                log_debug("key table %s (no pane)", table->name);
        else
                log_debug("key table %s (pane %%%u)", table->name, wp->id);
        if (c->flags & CLIENT_REPEAT)
                log_debug("currently repeating");

        bd = key_bindings_get(table, key0);

        /*
         * If prefix-timeout is enabled and we're in the prefix table, see if
         * the timeout has been exceeded. Revert to the root table if so.
         */
        prefix_delay = options_get_number(global_options, "prefix-timeout");
        if (prefix_delay > 0 &&
            strcmp(table->name, "prefix") == 0 &&
            server_client_key_table_activity_diff(c) > prefix_delay) {
                /*
                 * If repeating is active and this is a repeating binding,
                 * ignore the timeout.
                 */
                if (bd != NULL &&
                    (c->flags & CLIENT_REPEAT) &&
                    (bd->flags & KEY_BINDING_REPEAT)) {
                        log_debug("prefix timeout ignored, repeat is active");
                } else {
                        log_debug("prefix timeout exceeded");
                        server_client_set_key_table(c, NULL);
                        first = table = c->keytable;
                        server_status_client(c);
                        goto table_changed;
                }
        }

        /* Try to see if there is a key binding in the current table. */
        if (bd != NULL) {
                /*
                 * Key was matched in this table. If currently repeating but a
                 * non-repeating binding was found, stop repeating and try
                 * again in the root table.
                 */
                if ((c->flags & CLIENT_REPEAT) &&
                    (~bd->flags & KEY_BINDING_REPEAT)) {
                        log_debug("found in key table %s (not repeating)",
                            table->name);
                        server_client_set_key_table(c, NULL);
                        first = table = c->keytable;
                        c->flags &= ~CLIENT_REPEAT;
                        server_status_client(c);
                        goto table_changed;
                }
                log_debug("found in key table %s", table->name);

                /*
                 * Take a reference to this table to make sure the key binding
                 * doesn't disappear.
                 */
                table->references++;

                /*
                 * If this is a repeating key, start the timer. Otherwise reset
                 * the client back to the root table.
                 */
                repeat = server_client_repeat_time(c, bd);
                if (repeat != 0) {
                        c->flags |= CLIENT_REPEAT;
                        c->last_key = bd->key;

                        tv.tv_sec = repeat / 1000;
                        tv.tv_usec = (repeat % 1000) * 1000L;
                        evtimer_del(&c->repeat_timer);
                        evtimer_add(&c->repeat_timer, &tv);
                } else {
                        c->flags &= ~CLIENT_REPEAT;
                        server_client_set_key_table(c, NULL);
                }
                server_status_client(c);

                /* Execute the key binding. */
                key_bindings_dispatch(bd, item, c, event, &fs);
                key_bindings_unref_table(table);
                goto out;
        }

        /*
         * No match, try the ANY key.
         */
        if (key0 != KEYC_ANY) {
                key0 = KEYC_ANY;
                goto try_again;
        }

        /*
         * Binding movement keys is useless since we only turn them on when the
         * application requests, so don't let them exit the prefix table.
         */
        if (key == KEYC_MOUSEMOVE_PANE ||
            key == KEYC_MOUSEMOVE_STATUS ||
            key == KEYC_MOUSEMOVE_STATUS_LEFT ||
            key == KEYC_MOUSEMOVE_STATUS_RIGHT ||
            key == KEYC_MOUSEMOVE_STATUS_DEFAULT ||
            key == KEYC_MOUSEMOVE_BORDER)
                goto forward_key;

        /*
         * No match in this table. If not in the root table or if repeating
         * switch the client back to the root table and try again.
         */
        log_debug("not found in key table %s", table->name);
        if (!server_client_is_default_key_table(c, table) ||
            (c->flags & CLIENT_REPEAT)) {
                log_debug("trying in root table");
                server_client_set_key_table(c, NULL);
                table = c->keytable;
                if (c->flags & CLIENT_REPEAT)
                        first = table;
                c->flags &= ~CLIENT_REPEAT;
                server_status_client(c);
                goto table_changed;
        }

        /*
         * No match in the root table either. If this wasn't the first table
         * tried, don't pass the key to the pane.
         */
        if (first != table && (~flags & CLIENT_REPEAT)) {
                server_client_set_key_table(c, NULL);
                server_status_client(c);
                goto out;
        }

forward_key:
        if (wp != NULL &&
            (wp->flags & PANE_EXITED) &&
            !KEYC_IS_MOUSE(key) &&
            !KEYC_IS_PASTE(key) &&
            options_get_number(wp->options, "remain-on-exit") == 3) {
                options_set_number(wp->options, "remain-on-exit", 0);
                server_destroy_pane(wp, 0);
                goto out;
        }
        if (c->flags & CLIENT_READONLY)
                goto out;
        if (wp != NULL)
                window_pane_key(wp, c, s, wl, key, m);
        goto out;

paste_key:
        if (c->flags & CLIENT_READONLY)
                goto out;
        if (event->buf != NULL)
                window_pane_paste(wp, key, event->buf, event->len);
        key = KEYC_NONE;
        goto out;

out:
        if (s != NULL && key != KEYC_FOCUS_OUT)
                server_client_update_latest(c);
        free(event->buf);
        free(event);
        return (CMD_RETURN_NORMAL);
}

/* Handle a key event. */
int
server_client_handle_key(struct client *c, struct key_event *event)
{
        struct session          *s = c->session;
        struct cmdq_item        *item;

        /* Check the client is good to accept input. */
        if (s == NULL || (c->flags & CLIENT_UNATTACHEDFLAGS))
                return (0);

        /*
         * Handle theme reporting keys before overlays so they work even when a
         * popup is open.
         */
        if (event->key == KEYC_REPORT_LIGHT_THEME) {
                server_client_report_theme(c, THEME_LIGHT);
                return (0);
        }
        if (event->key == KEYC_REPORT_DARK_THEME) {
                server_client_report_theme(c, THEME_DARK);
                return (0);
        }

        /*
         * Key presses in overlay mode and the command prompt are a special
         * case. The queue might be blocked so they need to be processed
         * immediately rather than queued.
         */
        if (~c->flags & CLIENT_READONLY) {
                if (c->message_string != NULL) {
                        if (c->message_ignore_keys)
                                return (0);
                        status_message_clear(c);
                }
                if (c->overlay_key != NULL) {
                        switch (c->overlay_key(c, c->overlay_data, event)) {
                        case 0:
                                return (0);
                        case 1:
                                server_client_clear_overlay(c);
                                return (0);
                        }
                }
                server_client_clear_overlay(c);
                if (c->prompt_string != NULL) {
                        if (status_prompt_key(c, event->key) == 0)
                                return (0);
                }
        }

        /*
         * Add the key to the queue so it happens after any commands queued by
         * previous keys.
         */
        item = cmdq_get_callback(server_client_key_callback, event);
        cmdq_append(c, item);
        return (1);
}

/* Client functions that need to happen every loop. */
void
server_client_loop(void)
{
        struct client                   *c;
        struct window                   *w;
        struct window_pane              *wp;
        struct window_mode_entry        *wme;

        /* Check for window resize. This is done before redrawing. */
        RB_FOREACH(w, windows, &windows)
                server_client_check_window_resize(w);

        /* Notify modes that pane styles may have changed. */
        RB_FOREACH(w, windows, &windows) {
                TAILQ_FOREACH(wp, &w->panes, entry) {
                        if (wp->flags & PANE_STYLECHANGED) {
                                wme = TAILQ_FIRST(&wp->modes);
                                if (wme != NULL &&
                                    wme->mode->style_changed != NULL)
                                        wme->mode->style_changed(wme);
                        }
                }
        }

        /* Check clients. */
        TAILQ_FOREACH(c, &clients, entry) {
                server_client_check_exit(c);
                if (c->session != NULL && c->session->curw != NULL) {
                        server_client_check_modes(c);
                        server_client_check_redraw(c);
                        server_client_reset_state(c);
                }
        }

        /*
         * Any windows will have been redrawn as part of clients, so clear
         * their flags now.
         */
        RB_FOREACH(w, windows, &windows) {
                TAILQ_FOREACH(wp, &w->panes, entry) {
                        if (wp->fd != -1) {
                                server_client_check_pane_resize(wp);
                                server_client_check_pane_buffer(wp);
                        }
                        wp->flags &= ~(PANE_REDRAW|PANE_REDRAWSCROLLBAR);
                }
                check_window_name(w);
        }

        /* Send theme updates. */
        RB_FOREACH(w, windows, &windows) {
                TAILQ_FOREACH(wp, &w->panes, entry)
                        window_pane_send_theme_update(wp);
        }
}

/* Check if window needs to be resized. */
static void
server_client_check_window_resize(struct window *w)
{
        struct winlink  *wl;

        if (~w->flags & WINDOW_RESIZE)
                return;

        TAILQ_FOREACH(wl, &w->winlinks, wentry) {
                if (wl->session->attached != 0 && wl->session->curw == wl)
                        break;
        }
        if (wl == NULL)
                return;

        log_debug("%s: resizing window @%u", __func__, w->id);
        resize_window(w, w->new_sx, w->new_sy, w->new_xpixel, w->new_ypixel);
}

/* Resize timer event. */
static void
server_client_resize_timer(__unused int fd, __unused short events, void *data)
{
        struct window_pane      *wp = data;

        log_debug("%s: %%%u resize timer expired", __func__, wp->id);
        evtimer_del(&wp->resize_timer);
}

/* Check if pane should be resized. */
static void
server_client_check_pane_resize(struct window_pane *wp)
{
        struct window_pane_resize       *r;
        struct window_pane_resize       *r1;
        struct window_pane_resize       *first;
        struct window_pane_resize       *last;
        struct timeval                   tv = { .tv_usec = 250000 };

        if (TAILQ_EMPTY(&wp->resize_queue))
                return;

        if (!event_initialized(&wp->resize_timer))
                evtimer_set(&wp->resize_timer, server_client_resize_timer, wp);
        if (evtimer_pending(&wp->resize_timer, NULL))
                return;

        log_debug("%s: %%%u needs to be resized", __func__, wp->id);
        TAILQ_FOREACH(r, &wp->resize_queue, entry) {
                log_debug("queued resize: %ux%u -> %ux%u", r->osx, r->osy,
                    r->sx, r->sy);
        }

        /*
         * There are three cases that matter:
         *
         * - Only one resize. It can just be applied.
         *
         * - Multiple resizes and the ending size is different from the
         *   starting size. We can discard all resizes except the most recent.
         *
         * - Multiple resizes and the ending size is the same as the starting
         *   size. We must resize at least twice to force the application to
         *   redraw. So apply the first and leave the last on the queue for
         *   next time.
         */
        first = TAILQ_FIRST(&wp->resize_queue);
        last = TAILQ_LAST(&wp->resize_queue, window_pane_resizes);
        if (first == last) {
                /* Only one resize. */
                window_pane_send_resize(wp, first->sx, first->sy);
                TAILQ_REMOVE(&wp->resize_queue, first, entry);
                free(first);
        } else if (last->sx != first->osx || last->sy != first->osy) {
                /* Multiple resizes ending up with a different size. */
                window_pane_send_resize(wp, last->sx, last->sy);
                TAILQ_FOREACH_SAFE(r, &wp->resize_queue, entry, r1) {
                        TAILQ_REMOVE(&wp->resize_queue, r, entry);
                        free(r);
                }
        } else {
                /*
                 * Multiple resizes ending up with the same size. There will
                 * not be more than one to the same size in succession so we
                 * can just use the last-but-one on the list and leave the last
                 * for later. We reduce the time until the next check to avoid
                 * a long delay between the resizes.
                 */
                r = TAILQ_PREV(last, window_pane_resizes, entry);
                window_pane_send_resize(wp, r->sx, r->sy);
                TAILQ_FOREACH_SAFE(r, &wp->resize_queue, entry, r1) {
                        if (r == last)
                                break;
                        TAILQ_REMOVE(&wp->resize_queue, r, entry);
                        free(r);
                }
                tv.tv_usec = 10000;
        }
        evtimer_add(&wp->resize_timer, &tv);
}

/* Check pane buffer size. */
static void
server_client_check_pane_buffer(struct window_pane *wp)
{
        struct evbuffer                 *evb = wp->event->input;
        size_t                           minimum;
        struct client                   *c;
        struct window_pane_offset       *wpo;
        int                              off = 1, flag;
        u_int                            attached_clients = 0;
        size_t                           new_size;

        /*
         * Work out the minimum used size. This is the most that can be removed
         * from the buffer.
         */
        minimum = wp->offset.used;
        if (wp->pipe_fd != -1 && wp->pipe_offset.used < minimum)
                minimum = wp->pipe_offset.used;
        TAILQ_FOREACH(c, &clients, entry) {
                if (c->session == NULL)
                        continue;
                attached_clients++;

                if (~c->flags & CLIENT_CONTROL) {
                        off = 0;
                        continue;
                }
                wpo = control_pane_offset(c, wp, &flag);
                if (wpo == NULL) {
                        if (!flag)
                                off = 0;
                        continue;
                }
                if (!flag)
                        off = 0;

                window_pane_get_new_data(wp, wpo, &new_size);
                log_debug("%s: %s has %zu bytes used and %zu left for %%%u",
                    __func__, c->name, wpo->used - wp->base_offset, new_size,
                    wp->id);
                if (wpo->used < minimum)
                        minimum = wpo->used;
        }
        if (attached_clients == 0)
                off = 0;
        minimum -= wp->base_offset;
        if (minimum == 0)
                goto out;

        /* Drain the buffer. */
        log_debug("%s: %%%u has %zu minimum (of %zu) bytes used", __func__,
            wp->id, minimum, EVBUFFER_LENGTH(evb));
        evbuffer_drain(evb, minimum);

        /*
         * Adjust the base offset. If it would roll over, all the offsets into
         * the buffer need to be adjusted.
         */
        if (wp->base_offset > SIZE_MAX - minimum) {
                log_debug("%s: %%%u base offset has wrapped", __func__, wp->id);
                wp->offset.used -= wp->base_offset;
                if (wp->pipe_fd != -1)
                        wp->pipe_offset.used -= wp->base_offset;
                TAILQ_FOREACH(c, &clients, entry) {
                        if (c->session == NULL || (~c->flags & CLIENT_CONTROL))
                                continue;
                        wpo = control_pane_offset(c, wp, &flag);
                        if (wpo != NULL && !flag)
                                wpo->used -= wp->base_offset;
                }
                wp->base_offset = minimum;
        } else
                wp->base_offset += minimum;

out:
        /*
         * If there is data remaining, and there are no clients able to consume
         * it, do not read any more. This is true when there are attached
         * clients, all of which are control clients which are not able to
         * accept any more data.
         */
        log_debug("%s: pane %%%u is %s", __func__, wp->id, off ? "off" : "on");
        if (off)
                bufferevent_disable(wp->event, EV_READ);
        else
                bufferevent_enable(wp->event, EV_READ);
}

/*
 * Update cursor position and mode settings. The scroll region and attributes
 * are cleared when idle (waiting for an event) as this is the most likely time
 * a user may interrupt tmux, for example with ~^Z in ssh(1). This is a
 * compromise between excessive resets and likelihood of an interrupt.
 *
 * tty_region/tty_reset/tty_update_mode already take care of not resetting
 * things that are already in their default state.
 */
static void
server_client_reset_state(struct client *c)
{
        struct tty              *tty = &c->tty;
        struct window           *w = c->session->curw->window;
        struct window_pane      *wp = server_client_get_pane(c), *loop;
        struct screen           *s = NULL;
        struct options          *oo = c->session->options;
        int                      mode = 0, cursor, flags;
        u_int                    cx = 0, cy = 0, ox, oy, sx, sy, n;

        if (c->flags & (CLIENT_CONTROL|CLIENT_SUSPENDED))
                return;

        /* Disable the block flag. */
        flags = (tty->flags & TTY_BLOCK);
        tty->flags &= ~TTY_BLOCK;

        /* Get mode from overlay if any, else from screen. */
        if (c->overlay_draw != NULL) {
                if (c->overlay_mode != NULL)
                        s = c->overlay_mode(c, c->overlay_data, &cx, &cy);
        } else if (c->prompt_string == NULL)
                s = wp->screen;
        else
                s = c->status.active;
        if (s != NULL)
                mode = s->mode;
        if (log_get_level() != 0) {
                log_debug("%s: client %s mode %s", __func__, c->name,
                    screen_mode_to_string(mode));
        }

        /* Reset region and margin. */
        tty_region_off(tty);
        tty_margin_off(tty);

        /* Move cursor to pane cursor and offset. */
        if (c->prompt_string != NULL) {
                n = options_get_number(oo, "status-position");
                if (n == 0)
                        cy = status_prompt_line_at(c);
                else {
                        n = status_line_size(c) - status_prompt_line_at(c);
                        if (n <= tty->sy)
                                cy = tty->sy - n;
                        else
                                cy = tty->sy - 1;
                }
                cx = c->prompt_cursor;
        } else if (c->overlay_draw == NULL) {
                cursor = 0;
                tty_window_offset(tty, &ox, &oy, &sx, &sy);
                if (wp->xoff + s->cx >= ox && wp->xoff + s->cx <= ox + sx &&
                    wp->yoff + s->cy >= oy && wp->yoff + s->cy <= oy + sy) {
                        cursor = 1;

                        cx = wp->xoff + s->cx - ox;
                        cy = wp->yoff + s->cy - oy;

                        if (status_at_line(c) == 0)
                                cy += status_line_size(c);
                }
                if (!cursor)
                        mode &= ~MODE_CURSOR;
        }
        log_debug("%s: cursor to %u,%u", __func__, cx, cy);
        tty_cursor(tty, cx, cy);

        /*
         * Set mouse mode if requested. To support dragging, always use button
         * mode. For focus-follows-mouse, we need all-motion mode to receive
         * movement events.
         */
        if (options_get_number(oo, "mouse")) {
                if (c->overlay_draw == NULL) {
                        mode &= ~ALL_MOUSE_MODES;
                        TAILQ_FOREACH(loop, &w->panes, entry) {
                                if (loop->screen->mode & MODE_MOUSE_ALL)
                                        mode |= MODE_MOUSE_ALL;
                        }
                }
                if (options_get_number(oo, "focus-follows-mouse"))
                        mode |= MODE_MOUSE_ALL;
                else if (~mode & MODE_MOUSE_ALL)
                        mode |= MODE_MOUSE_BUTTON;
        }

        /* Clear bracketed paste mode if at the prompt. */
        if (c->overlay_draw == NULL && c->prompt_string != NULL)
                mode &= ~MODE_BRACKETPASTE;

        /* Set the terminal mode and reset attributes. */
        tty_update_mode(tty, mode, s);
        tty_reset(tty);

        /* All writing must be done, send a sync end (if it was started). */
        tty_sync_end(tty);
        tty->flags |= flags;
}

/* Repeat time callback. */
static void
server_client_repeat_timer(__unused int fd, __unused short events, void *data)
{
        struct client   *c = data;

        if (c->flags & CLIENT_REPEAT) {
                server_client_set_key_table(c, NULL);
                c->flags &= ~CLIENT_REPEAT;
                server_status_client(c);
        }
}

/* Double-click callback. */
static void
server_client_click_timer(__unused int fd, __unused short events, void *data)
{
        struct client           *c = data;
        struct key_event        *event;

        log_debug("click timer expired");

        if (c->flags & CLIENT_TRIPLECLICK) {
                /*
                 * Waiting for a third click that hasn't happened, so this must
                 * have been a double click.
                 */
                event = xcalloc(1, sizeof *event);
                event->key = KEYC_DOUBLECLICK;
                memcpy(&event->m, &c->click_event, sizeof event->m);
                if (!server_client_handle_key(c, event)) {
                        free(event->buf);
                        free(event);
                }
        }
        c->flags &= ~(CLIENT_DOUBLECLICK|CLIENT_TRIPLECLICK);
}

/* Check if client should be exited. */
static void
server_client_check_exit(struct client *c)
{
        struct client_file      *cf;
        const char              *name = c->exit_session;
        char                    *data;
        size_t                   size, msize;

        if (c->flags & (CLIENT_DEAD|CLIENT_EXITED))
                return;
        if (~c->flags & CLIENT_EXIT)
                return;

        if (c->flags & CLIENT_CONTROL) {
                control_discard(c);
                if (!control_all_done(c))
                        return;
        }
        RB_FOREACH(cf, client_files, &c->files) {
                if (EVBUFFER_LENGTH(cf->buffer) != 0)
                        return;
        }
        c->flags |= CLIENT_EXITED;

        switch (c->exit_type) {
        case CLIENT_EXIT_RETURN:
                if (c->exit_message != NULL)
                        msize = strlen(c->exit_message) + 1;
                else
                        msize = 0;
                size = (sizeof c->retval) + msize;
                data = xmalloc(size);
                memcpy(data, &c->retval, sizeof c->retval);
                if (c->exit_message != NULL)
                        memcpy(data + sizeof c->retval, c->exit_message, msize);
                proc_send(c->peer, MSG_EXIT, -1, data, size);
                free(data);
                break;
        case CLIENT_EXIT_SHUTDOWN:
                proc_send(c->peer, MSG_SHUTDOWN, -1, NULL, 0);
                break;
        case CLIENT_EXIT_DETACH:
                proc_send(c->peer, c->exit_msgtype, -1, name, strlen(name) + 1);
                break;
        }
        free(c->exit_session);
        free(c->exit_message);
}

/* Redraw timer callback. */
static void
server_client_redraw_timer(__unused int fd, __unused short events,
    __unused void *data)
{
        log_debug("redraw timer fired");
}

/*
 * Check if modes need to be updated. Only modes in the current window are
 * updated and it is done when the status line is redrawn.
 */
static void
server_client_check_modes(struct client *c)
{
        struct window                   *w = c->session->curw->window;
        struct window_pane              *wp;
        struct window_mode_entry        *wme;

        if (c->flags & (CLIENT_CONTROL|CLIENT_SUSPENDED))
                return;
        if (~c->flags & CLIENT_REDRAWSTATUS)
                return;
        TAILQ_FOREACH(wp, &w->panes, entry) {
                wme = TAILQ_FIRST(&wp->modes);
                if (wme != NULL && wme->mode->update != NULL)
                        wme->mode->update(wme);
        }
}

/* Check for client redraws. */
static void
server_client_check_redraw(struct client *c)
{
        struct session          *s = c->session;
        struct tty              *tty = &c->tty;
        struct window           *w = c->session->curw->window;
        struct window_pane      *wp;
        int                      needed, tty_flags, mode = tty->mode;
        uint64_t                 client_flags = 0;
        int                      redraw_pane, redraw_scrollbar_only;
        u_int                    bit = 0;
        struct timeval           tv = { .tv_usec = 1000 };
        static struct event      ev;
        size_t                   left;

        if (c->flags & (CLIENT_CONTROL|CLIENT_SUSPENDED))
                return;
        if (c->flags & CLIENT_ALLREDRAWFLAGS) {
                log_debug("%s: redraw%s%s%s%s%s%s", c->name,
                    (c->flags & CLIENT_REDRAWWINDOW) ? " window" : "",
                    (c->flags & CLIENT_REDRAWSTATUS) ? " status" : "",
                    (c->flags & CLIENT_REDRAWBORDERS) ? " borders" : "",
                    (c->flags & CLIENT_REDRAWOVERLAY) ? " overlay" : "",
                    (c->flags & CLIENT_REDRAWPANES) ? " panes" : "",
                    (c->flags & CLIENT_REDRAWSCROLLBARS) ? " scrollbars" : "");
        }

        /*
         * If there is outstanding data, defer the redraw until it has been
         * consumed. We can just add a timer to get out of the event loop and
         * end up back here.
         */
        needed = 0;
        if (c->flags & CLIENT_ALLREDRAWFLAGS)
                needed = 1;
        else {
                TAILQ_FOREACH(wp, &w->panes, entry) {
                        if (wp->flags & PANE_REDRAW) {
                                needed = 1;
                                client_flags |= CLIENT_REDRAWPANES;
                                break;
                        }
                        if (wp->flags & PANE_REDRAWSCROLLBAR) {
                                needed = 1;
                                client_flags |= CLIENT_REDRAWSCROLLBARS;
                                /* no break - later panes may need redraw */
                        }
                }
        }
        if (needed && (left = EVBUFFER_LENGTH(tty->out)) != 0) {
                log_debug("%s: redraw deferred (%zu left)", c->name, left);
                if (!evtimer_initialized(&ev))
                        evtimer_set(&ev, server_client_redraw_timer, NULL);
                if (!evtimer_pending(&ev, NULL)) {
                        log_debug("redraw timer started");
                        evtimer_add(&ev, &tv);
                }

                if (~c->flags & CLIENT_REDRAWWINDOW) {
                        TAILQ_FOREACH(wp, &w->panes, entry) {
                                if (wp->flags & (PANE_REDRAW)) {
                                        log_debug("%s: pane %%%u needs redraw",
                                            c->name, wp->id);
                                        c->redraw_panes |= (1 << bit);
                                } else if (wp->flags & PANE_REDRAWSCROLLBAR) {
                                        log_debug("%s: pane %%%u scrollbar "
                                            "needs redraw", c->name, wp->id);
                                        c->redraw_scrollbars |= (1 << bit);
                                }
                                if (++bit == 64) {
                                        /*
                                         * If more that 64 panes, give up and
                                         * just redraw the window.
                                         */
                                        client_flags &= ~(CLIENT_REDRAWPANES|
                                            CLIENT_REDRAWSCROLLBARS);
                                        client_flags |= CLIENT_REDRAWWINDOW;
                                        break;
                                }
                        }
                        if (c->redraw_panes != 0)
                                c->flags |= CLIENT_REDRAWPANES;
                        if (c->redraw_scrollbars != 0)
                                c->flags |= CLIENT_REDRAWSCROLLBARS;
                }
                c->flags |= client_flags;
                return;
        } else if (needed)
                log_debug("%s: redraw needed", c->name);

        tty_flags = tty->flags & (TTY_BLOCK|TTY_FREEZE|TTY_NOCURSOR);
        tty->flags = (tty->flags & ~(TTY_BLOCK|TTY_FREEZE))|TTY_NOCURSOR;

        if (~c->flags & CLIENT_REDRAWWINDOW) {
                /*
                 * If not redrawing the entire window, check whether each pane
                 * needs to be redrawn.
                 */
                TAILQ_FOREACH(wp, &w->panes, entry) {
                        redraw_pane = 0;
                        redraw_scrollbar_only = 0;
                        if (wp->flags & PANE_REDRAW)
                                redraw_pane = 1;
                        else if (c->flags & CLIENT_REDRAWPANES) {
                                if (c->redraw_panes & (1 << bit))
                                        redraw_pane = 1;
                        } else if (c->flags & CLIENT_REDRAWSCROLLBARS) {
                                if (c->redraw_scrollbars & (1 << bit))
                                        redraw_scrollbar_only = 1;
                        }
                        bit++;
                        if (!redraw_pane && !redraw_scrollbar_only)
                                continue;
                        if (redraw_scrollbar_only) {
                                log_debug("%s: redrawing (scrollbar only) pane "
                                    "%%%u", __func__, wp->id);
                        } else {
                                log_debug("%s: redrawing pane %%%u", __func__,
                                    wp->id);
                        }
                        screen_redraw_pane(c, wp, redraw_scrollbar_only);
                }
                c->redraw_panes = 0;
                c->redraw_scrollbars = 0;
                c->flags &= ~(CLIENT_REDRAWPANES|CLIENT_REDRAWSCROLLBARS);
        }

        if (c->flags & CLIENT_ALLREDRAWFLAGS) {
                if (options_get_number(s->options, "set-titles")) {
                        server_client_set_title(c);
                        server_client_set_path(c);
                }
                screen_redraw_screen(c);
        }

        tty->flags = (tty->flags & ~TTY_NOCURSOR)|(tty_flags & TTY_NOCURSOR);
        tty_update_mode(tty, mode, NULL);
        tty->flags = (tty->flags & ~(TTY_BLOCK|TTY_FREEZE|TTY_NOCURSOR))|
            tty_flags;

        c->flags &= ~(CLIENT_ALLREDRAWFLAGS|CLIENT_STATUSFORCE);

        if (needed) {
                /*
                 * We would have deferred the redraw unless the output buffer
                 * was empty, so we can record how many bytes the redraw
                 * generated.
                 */
                c->redraw = EVBUFFER_LENGTH(tty->out);
                log_debug("%s: redraw added %zu bytes", c->name, c->redraw);
        }
}

/* Set client title. */
static void
server_client_set_title(struct client *c)
{
        struct session          *s = c->session;
        const char              *template;
        char                    *title;
        struct format_tree      *ft;

        template = options_get_string(s->options, "set-titles-string");

        ft = format_create(c, NULL, FORMAT_NONE, 0);
        format_defaults(ft, c, NULL, NULL, NULL);

        title = format_expand_time(ft, template);
        if (c->title == NULL || strcmp(title, c->title) != 0) {
                free(c->title);
                c->title = xstrdup(title);
                tty_set_title(&c->tty, c->title);
        }
        free(title);

        format_free(ft);
}

/* Set client path. */
static void
server_client_set_path(struct client *c)
{
        struct session  *s = c->session;
        const char      *path;

        if (s->curw == NULL)
                return;
        if (s->curw->window->active->base.path == NULL)
                path = "";
        else
                path = s->curw->window->active->base.path;
        if (c->path == NULL || strcmp(path, c->path) != 0) {
                free(c->path);
                c->path = xstrdup(path);
                tty_set_path(&c->tty, c->path);
        }
}

/* Dispatch message from client. */
static void
server_client_dispatch(struct imsg *imsg, void *arg)
{
        struct client   *c = arg;
        ssize_t          datalen;
        struct session  *s;

        if (c->flags & CLIENT_DEAD)
                return;

        if (imsg == NULL) {
                server_client_lost(c);
                return;
        }

        datalen = imsg->hdr.len - IMSG_HEADER_SIZE;

        switch (imsg->hdr.type) {
        case MSG_IDENTIFY_CLIENTPID:
        case MSG_IDENTIFY_CWD:
        case MSG_IDENTIFY_ENVIRON:
        case MSG_IDENTIFY_FEATURES:
        case MSG_IDENTIFY_FLAGS:
        case MSG_IDENTIFY_LONGFLAGS:
        case MSG_IDENTIFY_STDIN:
        case MSG_IDENTIFY_STDOUT:
        case MSG_IDENTIFY_TERM:
        case MSG_IDENTIFY_TERMINFO:
        case MSG_IDENTIFY_TTYNAME:
        case MSG_IDENTIFY_DONE:
                if (server_client_dispatch_identify(c, imsg) != 0)
                        goto bad;
                break;
        case MSG_COMMAND:
                if (server_client_dispatch_command(c, imsg) != 0)
                        goto bad;
                break;
        case MSG_RESIZE:
                if (datalen != 0)
                        goto bad;

                if (c->flags & CLIENT_CONTROL)
                        break;
                server_client_update_latest(c);
                tty_resize(&c->tty);
                tty_repeat_requests(&c->tty, 0);
                recalculate_sizes();
                if (c->overlay_resize == NULL)
                        server_client_clear_overlay(c);
                else
                        c->overlay_resize(c, c->overlay_data);
                server_redraw_client(c);
                if (c->session != NULL)
                        notify_client("client-resized", c);
                break;
        case MSG_EXITING:
                if (datalen != 0)
                        goto bad;
                server_client_set_session(c, NULL);
                recalculate_sizes();
                tty_close(&c->tty);
                proc_send(c->peer, MSG_EXITED, -1, NULL, 0);
                break;
        case MSG_WAKEUP:
        case MSG_UNLOCK:
                if (datalen != 0)
                        goto bad;

                if (!(c->flags & CLIENT_SUSPENDED))
                        break;
                c->flags &= ~CLIENT_SUSPENDED;

                if (c->fd == -1 || c->session == NULL) /* exited already */
                        break;
                s = c->session;

                if (gettimeofday(&c->activity_time, NULL) != 0)
                        fatal("gettimeofday failed");

                tty_start_tty(&c->tty);
                server_redraw_client(c);
                recalculate_sizes();

                if (s != NULL)
                        session_update_activity(s, &c->activity_time);
                break;
        case MSG_SHELL:
                if (datalen != 0)
                        goto bad;
                if (server_client_dispatch_shell(c) != 0)
                        goto bad;
                break;
        case MSG_WRITE_READY:
                file_write_ready(&c->files, imsg);
                break;
        case MSG_READ:
                file_read_data(&c->files, imsg);
                break;
        case MSG_READ_DONE:
                file_read_done(&c->files, imsg);
                break;
        }

        return;

bad:
        log_debug("client %p invalid message type %d", c, imsg->hdr.type);
        proc_kill_peer(c->peer);
}

/* Callback when command is not allowed. */
static enum cmd_retval
server_client_read_only(struct cmdq_item *item, __unused void *data)
{
        cmdq_error(item, "client is read-only");
        return (CMD_RETURN_ERROR);
}

/* Callback for default command. */
static enum cmd_retval
server_client_default_command(struct cmdq_item *item, __unused void *data)
{
        struct client           *c = cmdq_get_client(item);
        struct cmd_list         *cmdlist;
        struct cmdq_item        *new_item;

        cmdlist = options_get_command(global_options, "default-client-command");
        if ((c->flags & CLIENT_READONLY) &&
            !cmd_list_all_have(cmdlist, CMD_READONLY))
                new_item = cmdq_get_callback(server_client_read_only, NULL);
        else
                new_item = cmdq_get_command(cmdlist, NULL);
        cmdq_insert_after(item, new_item);
        return (CMD_RETURN_NORMAL);
}

/* Callback when command is done. */
static enum cmd_retval
server_client_command_done(struct cmdq_item *item, __unused void *data)
{
        struct client   *c = cmdq_get_client(item);

        if (~c->flags & CLIENT_ATTACHED)
                c->flags |= CLIENT_EXIT;
        else if (~c->flags & CLIENT_EXIT) {
                if (c->flags & CLIENT_CONTROL)
                        control_ready(c);
                tty_send_requests(&c->tty);
        }
        return (CMD_RETURN_NORMAL);
}

/* Handle command message. */
static int
server_client_dispatch_command(struct client *c, struct imsg *imsg)
{
        struct msg_command        data;
        char                     *buf;
        size_t                    len;
        int                       argc = 0;
        char                    **argv, *cause;
        struct cmd_parse_result  *pr;
        struct args_value        *values;
        struct cmdq_item         *new_item;

        if (c->flags & CLIENT_EXIT)
                return (0);

        if (imsg->hdr.len - IMSG_HEADER_SIZE < sizeof data)
                return (-1);
        memcpy(&data, imsg->data, sizeof data);

        buf = (char *)imsg->data + sizeof data;
        len = imsg->hdr.len - IMSG_HEADER_SIZE - sizeof data;
        if (len > 0 && buf[len - 1] != '\0')
                return (-1);

        if (cmd_unpack_argv(buf, len, data.argc, &argv) != 0) {
                cause = xstrdup("command too long");
                goto error;
        }

        argc = data.argc;
        if (argc == 0) {
                new_item = cmdq_get_callback(server_client_default_command,
                    NULL);
        } else {
                values = args_from_vector(argc, argv);
                pr = cmd_parse_from_arguments(values, argc, NULL);
                switch (pr->status) {
                case CMD_PARSE_ERROR:
                        cause = pr->error;
                        goto error;
                case CMD_PARSE_SUCCESS:
                        break;
                }
                args_free_values(values, argc);
                free(values);
                cmd_free_argv(argc, argv);
                if ((c->flags & CLIENT_READONLY) &&
                    !cmd_list_all_have(pr->cmdlist, CMD_READONLY)) {
                        new_item = cmdq_get_callback(server_client_read_only,
                            NULL);
                } else
                        new_item = cmdq_get_command(pr->cmdlist, NULL);
                cmd_list_free(pr->cmdlist);
        }
        cmdq_append(c, new_item);
        cmdq_append(c, cmdq_get_callback(server_client_command_done, NULL));

        return (0);

error:
        cmd_free_argv(argc, argv);

        cmdq_append(c, cmdq_get_error(cause));
        free(cause);

        c->flags |= CLIENT_EXIT;
        return (0);
}

/* Handle identify message. */
static int
server_client_dispatch_identify(struct client *c, struct imsg *imsg)
{
        const char      *data, *home;
        size_t           datalen;
        int              flags, feat;
        uint64_t         longflags;
        char            *name;

        if (c->flags & CLIENT_IDENTIFIED)
                return (-1);

        data = imsg->data;
        datalen = imsg->hdr.len - IMSG_HEADER_SIZE;

        switch (imsg->hdr.type) {
        case MSG_IDENTIFY_FEATURES:
                if (datalen != sizeof feat)
                        return (-1);
                memcpy(&feat, data, sizeof feat);
                c->term_features |= feat;
                log_debug("client %p IDENTIFY_FEATURES %s", c,
                    tty_get_features(feat));
                break;
        case MSG_IDENTIFY_FLAGS:
                if (datalen != sizeof flags)
                        return (-1);
                memcpy(&flags, data, sizeof flags);
                c->flags |= flags;
                log_debug("client %p IDENTIFY_FLAGS %#x", c, flags);
                break;
        case MSG_IDENTIFY_LONGFLAGS:
                if (datalen != sizeof longflags)
                        return (-1);
                memcpy(&longflags, data, sizeof longflags);
                c->flags |= longflags;
                log_debug("client %p IDENTIFY_LONGFLAGS %#llx", c,
                    (unsigned long long)longflags);
                break;
        case MSG_IDENTIFY_TERM:
                if (datalen == 0 || data[datalen - 1] != '\0')
                        return (-1);
                c->term_name = xstrdup(data);
                log_debug("client %p IDENTIFY_TERM %s", c, data);
                break;
        case MSG_IDENTIFY_TERMINFO:
                if (datalen == 0 || data[datalen - 1] != '\0')
                        return (-1);
                c->term_caps = xreallocarray(c->term_caps, c->term_ncaps + 1,
                    sizeof *c->term_caps);
                c->term_caps[c->term_ncaps++] = xstrdup(data);
                log_debug("client %p IDENTIFY_TERMINFO %s", c, data);
                break;
        case MSG_IDENTIFY_TTYNAME:
                if (datalen == 0 || data[datalen - 1] != '\0')
                        return (-1);
                c->ttyname = xstrdup(data);
                log_debug("client %p IDENTIFY_TTYNAME %s", c, data);
                break;
        case MSG_IDENTIFY_CWD:
                if (datalen == 0 || data[datalen - 1] != '\0')
                        return (-1);
                if (access(data, X_OK) == 0)
                        c->cwd = xstrdup(data);
                else if ((home = find_home()) != NULL)
                        c->cwd = xstrdup(home);
                else
                        c->cwd = xstrdup("/");
                log_debug("client %p IDENTIFY_CWD %s", c, data);
                break;
        case MSG_IDENTIFY_STDIN:
                if (datalen != 0)
                        return (-1);
                c->fd = imsg_get_fd(imsg);
                log_debug("client %p IDENTIFY_STDIN %d", c, c->fd);
                break;
        case MSG_IDENTIFY_STDOUT:
                if (datalen != 0)
                        return (-1);
                c->out_fd = imsg_get_fd(imsg);
                log_debug("client %p IDENTIFY_STDOUT %d", c, c->out_fd);
                break;
        case MSG_IDENTIFY_ENVIRON:
                if (datalen == 0 || data[datalen - 1] != '\0')
                        return (-1);
                if (strchr(data, '=') != NULL)
                        environ_put(c->environ, data, 0);
                log_debug("client %p IDENTIFY_ENVIRON %s", c, data);
                break;
        case MSG_IDENTIFY_CLIENTPID:
                if (datalen != sizeof c->pid)
                        return (-1);
                memcpy(&c->pid, data, sizeof c->pid);
                log_debug("client %p IDENTIFY_CLIENTPID %ld", c, (long)c->pid);
                break;
        default:
                break;
        }

        if (imsg->hdr.type != MSG_IDENTIFY_DONE)
                return (0);
        c->flags |= CLIENT_IDENTIFIED;

        if (c->term_name == NULL || *c->term_name == '\0') {
                free(c->term_name);
                c->term_name = xstrdup("unknown");
        }

        if (c->ttyname != NULL && *c->ttyname != '\0')
                name = xstrdup(c->ttyname);
        else
                xasprintf(&name, "client-%ld", (long)c->pid);
        c->name = name;
        log_debug("client %p name is %s", c, c->name);

        if (c->flags & CLIENT_CONTROL)
                control_start(c);
        else if (c->fd != -1) {
                if (tty_init(&c->tty, c) != 0) {
                        close(c->fd);
                        c->fd = -1;
                } else {
                        tty_resize(&c->tty);
                        c->flags |= CLIENT_TERMINAL;
                }
                if (c->out_fd != -1)
                        close(c->out_fd);
                c->out_fd = -1;
        }

        /*
         * If this is the first client, load configuration files. Any later
         * clients are allowed to continue with their command even if the
         * config has not been loaded - they might have been run from inside it
         */
        if ((~c->flags & CLIENT_EXIT) &&
             !cfg_finished &&
             c == TAILQ_FIRST(&clients))
                start_cfg();

        return (0);
}

/* Handle shell message. */
static int
server_client_dispatch_shell(struct client *c)
{
        const char      *shell;

        shell = options_get_string(global_s_options, "default-shell");
        if (!checkshell(shell))
                shell = _PATH_BSHELL;
        proc_send(c->peer, MSG_SHELL, -1, shell, strlen(shell) + 1);

        proc_kill_peer(c->peer);
        return (0);
}

/* Get client working directory. */
const char *
server_client_get_cwd(struct client *c, struct session *s)
{
        const char      *home;

        if (!cfg_finished && cfg_client != NULL)
                return (cfg_client->cwd);
        if (c != NULL && c->session == NULL && c->cwd != NULL)
                return (c->cwd);
        if (s != NULL && s->cwd != NULL)
                return (s->cwd);
        if (c != NULL && (s = c->session) != NULL && s->cwd != NULL)
                return (s->cwd);
        if ((home = find_home()) != NULL)
                return (home);
        return ("/");
}

/* Get control client flags. */
static uint64_t
server_client_control_flags(struct client *c, const char *next)
{
        if (strcmp(next, "pause-after") == 0) {
                c->pause_age = 0;
                return (CLIENT_CONTROL_PAUSEAFTER);
        }
        if (sscanf(next, "pause-after=%u", &c->pause_age) == 1) {
                c->pause_age *= 1000;
                return (CLIENT_CONTROL_PAUSEAFTER);
        }
        if (strcmp(next, "no-output") == 0)
                return (CLIENT_CONTROL_NOOUTPUT);
        if (strcmp(next, "wait-exit") == 0)
                return (CLIENT_CONTROL_WAITEXIT);
        return (0);
}

/* Set client flags. */
void
server_client_set_flags(struct client *c, const char *flags)
{
        char    *s, *copy, *next;
        uint64_t flag;
        int      not;

        s = copy = xstrdup(flags);
        while ((next = strsep(&s, ",")) != NULL) {
                not = (*next == '!');
                if (not)
                        next++;

                if (c->flags & CLIENT_CONTROL)
                        flag = server_client_control_flags(c, next);
                else
                        flag = 0;
                if (strcmp(next, "read-only") == 0)
                        flag = CLIENT_READONLY;
                else if (strcmp(next, "ignore-size") == 0)
                        flag = CLIENT_IGNORESIZE;
                else if (strcmp(next, "active-pane") == 0)
                        flag = CLIENT_ACTIVEPANE;
                else if (strcmp(next, "no-detach-on-destroy") == 0)
                        flag = CLIENT_NO_DETACH_ON_DESTROY;
                if (flag == 0)
                        continue;

                log_debug("client %s set flag %s", c->name, next);
                if (not) {
                        if (c->flags & CLIENT_READONLY)
                                flag &= ~CLIENT_READONLY;
                        c->flags &= ~flag;
                } else
                        c->flags |= flag;
                if (flag == CLIENT_CONTROL_NOOUTPUT)
                        control_reset_offsets(c);
        }
        free(copy);
        proc_send(c->peer, MSG_FLAGS, -1, &c->flags, sizeof c->flags);
}

/* Get client flags. This is only flags useful to show to users. */
const char *
server_client_get_flags(struct client *c)
{
        static char     s[256];
        char            tmp[32];

        *s = '\0';
        if (c->flags & CLIENT_ATTACHED)
                strlcat(s, "attached,", sizeof s);
        if (c->flags & CLIENT_FOCUSED)
                strlcat(s, "focused,", sizeof s);
        if (c->flags & CLIENT_CONTROL)
                strlcat(s, "control-mode,", sizeof s);
        if (c->flags & CLIENT_IGNORESIZE)
                strlcat(s, "ignore-size,", sizeof s);
        if (c->flags & CLIENT_NO_DETACH_ON_DESTROY)
                strlcat(s, "no-detach-on-destroy,", sizeof s);
        if (c->flags & CLIENT_CONTROL_NOOUTPUT)
                strlcat(s, "no-output,", sizeof s);
        if (c->flags & CLIENT_CONTROL_WAITEXIT)
                strlcat(s, "wait-exit,", sizeof s);
        if (c->flags & CLIENT_CONTROL_PAUSEAFTER) {
                xsnprintf(tmp, sizeof tmp, "pause-after=%u,",
                    c->pause_age / 1000);
                strlcat(s, tmp, sizeof s);
        }
        if (c->flags & CLIENT_READONLY)
                strlcat(s, "read-only,", sizeof s);
        if (c->flags & CLIENT_ACTIVEPANE)
                strlcat(s, "active-pane,", sizeof s);
        if (c->flags & CLIENT_SUSPENDED)
                strlcat(s, "suspended,", sizeof s);
        if (c->flags & CLIENT_UTF8)
                strlcat(s, "UTF-8,", sizeof s);
        if (*s != '\0')
                s[strlen(s) - 1] = '\0';
        return (s);
}

/* Get client window. */
struct client_window *
server_client_get_client_window(struct client *c, u_int id)
{
        struct client_window    cw = { .window = id };

        return (RB_FIND(client_windows, &c->windows, &cw));
}

/* Add client window. */
struct client_window *
server_client_add_client_window(struct client *c, u_int id)
{
        struct client_window    *cw;

        cw = server_client_get_client_window(c, id);
        if (cw == NULL) {
                cw = xcalloc(1, sizeof *cw);
                cw->window = id;
                RB_INSERT(client_windows, &c->windows, cw);
        }
        return (cw);
}

/* Get client active pane. */
struct window_pane *
server_client_get_pane(struct client *c)
{
        struct session          *s = c->session;
        struct client_window    *cw;

        if (s == NULL)
                return (NULL);

        if (~c->flags & CLIENT_ACTIVEPANE)
                return (s->curw->window->active);
        cw = server_client_get_client_window(c, s->curw->window->id);
        if (cw == NULL)
                return (s->curw->window->active);
        return (cw->pane);
}

/* Set client active pane. */
void
server_client_set_pane(struct client *c, struct window_pane *wp)
{
        struct session          *s = c->session;
        struct client_window    *cw;

        if (s == NULL)
                return;

        cw = server_client_add_client_window(c, s->curw->window->id);
        cw->pane = wp;
        log_debug("%s pane now %%%u", c->name, wp->id);
}

/* Remove pane from client lists. */
void
server_client_remove_pane(struct window_pane *wp)
{
        struct client           *c;
        struct window           *w = wp->window;
        struct client_window    *cw;

        TAILQ_FOREACH(c, &clients, entry) {
                cw = server_client_get_client_window(c, w->id);
                if (cw != NULL && cw->pane == wp) {
                        RB_REMOVE(client_windows, &c->windows, cw);
                        free(cw);
                }
        }
}

/* Print to a client. */
void
server_client_print(struct client *c, int parse, struct evbuffer *evb)
{
        void                            *data = EVBUFFER_DATA(evb);
        size_t                           size = EVBUFFER_LENGTH(evb);
        struct window_pane              *wp;
        struct window_mode_entry        *wme;
        char                            *sanitized, *msg, *line, empty = '\0';

        if (!parse) {
                utf8_stravisx(&msg, data, size,
                    VIS_OCTAL|VIS_CSTYLE|VIS_NOSLASH);
        } else {
                if (size == 0)
                        msg = &empty;
                else {
                        msg = EVBUFFER_DATA(evb);
                        if (msg[size - 1] != '\0')
                                evbuffer_add(evb, "", 1);
                }
        }
        log_debug("%s: %s", __func__, msg);

        if (c == NULL)
                goto out;

        if (c->session == NULL || (c->flags & CLIENT_CONTROL)) {
                if (~c->flags & CLIENT_UTF8) {
                        sanitized = utf8_sanitize(msg);
                        if (c->flags & CLIENT_CONTROL)
                                control_write(c, "%s", sanitized);
                        else
                                file_print(c, "%s\n", sanitized);
                        free(sanitized);
                } else {
                        if (c->flags & CLIENT_CONTROL)
                                control_write(c, "%s", msg);
                        else
                                file_print(c, "%s\n", msg);
                }
                goto out;
        }

        wp = server_client_get_pane(c);
        wme = TAILQ_FIRST(&wp->modes);
        if (wme == NULL || wme->mode != &window_view_mode)
                window_pane_set_mode(wp, NULL, &window_view_mode, NULL, NULL);
        if (parse) {
                do {
                        line = evbuffer_readln(evb, NULL, EVBUFFER_EOL_LF);
                        if (line != NULL) {
                                window_copy_add(wp, 1, "%s", line);
                                free(line);
                        }
                } while (line != NULL);

                size = EVBUFFER_LENGTH(evb);
                if (size != 0) {
                        line = EVBUFFER_DATA(evb);
                        window_copy_add(wp, 1, "%.*s", (int)size, line);
                }
        } else
                window_copy_add(wp, 0, "%s", msg);

out:
        if (!parse)
                free(msg);
}

static void
server_client_report_theme(struct client *c, enum client_theme theme)
{
        if (theme == THEME_LIGHT) {
                c->theme = THEME_LIGHT;
                notify_client("client-light-theme", c);
        } else {
                c->theme = THEME_DARK;
                notify_client("client-dark-theme", c);
        }

        /*
         * Request foreground and background colour again. Don't forward 2031 to
         * panes until a response is received.
         */
        tty_repeat_requests(&c->tty, 1);
}