source: mainline/uspace/app/terminal/terminal.c@ 554a5f1

/*
 * Copyright (c) 2020 Jiri Svoboda
 * Copyright (c) 2012 Petr Koupy
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup terminal
 * @{
 */
/**
 * @file Terminal application
 */

#include <adt/list.h>
#include <adt/prodcons.h>
#include <errno.h>
#include <fbfont/font-8x16.h>
#include <io/chargrid.h>
#include <gfx/bitmap.h>
#include <gfx/context.h>
#include <io/con_srv.h>
#include <io/concaps.h>
#include <io/console.h>
#include <io/pixelmap.h>
#include <task.h>
#include <stdarg.h>
#include <stdlib.h>
#include <str.h>
#include <ui/resource.h>
#include <ui/ui.h>
#include <ui/wdecor.h>
#include <ui/window.h>

#include "terminal.h"

#define NAME       "terminal"
#define NAMESPACE  "terminal"

#define LOCFS_MOUNT_POINT  "/loc"

#define APP_GETTERM  "/app/getterm"

#define TERM_CAPS \
        (CONSOLE_CAP_STYLE | CONSOLE_CAP_INDEXED | CONSOLE_CAP_RGB)

static LIST_INITIALIZE(terms);

static errno_t term_open(con_srvs_t *, con_srv_t *);
static errno_t term_close(con_srv_t *);
static errno_t term_read(con_srv_t *, void *, size_t, size_t *);
static errno_t term_write(con_srv_t *, void *, size_t, size_t *);
static void term_sync(con_srv_t *);
static void term_clear(con_srv_t *);
static void term_set_pos(con_srv_t *, sysarg_t col, sysarg_t row);
static errno_t term_get_pos(con_srv_t *, sysarg_t *, sysarg_t *);
static errno_t term_get_size(con_srv_t *, sysarg_t *, sysarg_t *);
static errno_t term_get_color_cap(con_srv_t *, console_caps_t *);
static void term_set_style(con_srv_t *, console_style_t);
static void term_set_color(con_srv_t *, console_color_t, console_color_t,
    console_color_attr_t);
static void term_set_rgb_color(con_srv_t *, pixel_t, pixel_t);
static void term_set_cursor_visibility(con_srv_t *, bool);
static errno_t term_get_event(con_srv_t *, cons_event_t *);

static con_ops_t con_ops = {
        .open = term_open,
        .close = term_close,
        .read = term_read,
        .write = term_write,
        .sync = term_sync,
        .clear = term_clear,
        .set_pos = term_set_pos,
        .get_pos = term_get_pos,
        .get_size = term_get_size,
        .get_color_cap = term_get_color_cap,
        .set_style = term_set_style,
        .set_color = term_set_color,
        .set_rgb_color = term_set_rgb_color,
        .set_cursor_visibility = term_set_cursor_visibility,
        .get_event = term_get_event
};

static void terminal_close_event(ui_window_t *, void *);
static void terminal_focus_event(ui_window_t *, void *);
static void terminal_kbd_event(ui_window_t *, void *, kbd_event_t *);
static void terminal_pos_event(ui_window_t *, void *, pos_event_t *);
static void terminal_unfocus_event(ui_window_t *, void *);

static ui_window_cb_t terminal_window_cb = {
        .close = terminal_close_event,
        .focus = terminal_focus_event,
        .kbd = terminal_kbd_event,
        .pos = terminal_pos_event,
        .unfocus = terminal_unfocus_event
};

static terminal_t *srv_to_terminal(con_srv_t *srv)
{
        return srv->srvs->sarg;
}

static void getterm(const char *svc, const char *app)
{
        task_spawnl(NULL, NULL, APP_GETTERM, APP_GETTERM, svc,
            LOCFS_MOUNT_POINT, "--msg", "--wait", "--", app, NULL);
}

static pixel_t color_table[16] = {
        [COLOR_BLACK]       = PIXEL(255, 0, 0, 0),
        [COLOR_BLUE]        = PIXEL(255, 0, 0, 240),
        [COLOR_GREEN]       = PIXEL(255, 0, 240, 0),
        [COLOR_CYAN]        = PIXEL(255, 0, 240, 240),
        [COLOR_RED]         = PIXEL(255, 240, 0, 0),
        [COLOR_MAGENTA]     = PIXEL(255, 240, 0, 240),
        [COLOR_YELLOW]      = PIXEL(255, 240, 240, 0),
        [COLOR_WHITE]       = PIXEL(255, 240, 240, 240),

        [COLOR_BLACK + 8]   = PIXEL(255, 0, 0, 0),
        [COLOR_BLUE + 8]    = PIXEL(255, 0, 0, 255),
        [COLOR_GREEN + 8]   = PIXEL(255, 0, 255, 0),
        [COLOR_CYAN + 8]    = PIXEL(255, 0, 255, 255),
        [COLOR_RED + 8]     = PIXEL(255, 255, 0, 0),
        [COLOR_MAGENTA + 8] = PIXEL(255, 255, 0, 255),
        [COLOR_YELLOW + 8]  = PIXEL(255, 255, 255, 0),
        [COLOR_WHITE + 8]   = PIXEL(255, 255, 255, 255),
};

static inline void attrs_rgb(char_attrs_t attrs, pixel_t *bgcolor, pixel_t *fgcolor)
{
        switch (attrs.type) {
        case CHAR_ATTR_STYLE:
                switch (attrs.val.style) {
                case STYLE_NORMAL:
                        *bgcolor = color_table[COLOR_WHITE];
                        *fgcolor = color_table[COLOR_BLACK];
                        break;
                case STYLE_EMPHASIS:
                        *bgcolor = color_table[COLOR_WHITE];
                        *fgcolor = color_table[COLOR_RED];
                        break;
                case STYLE_INVERTED:
                        *bgcolor = color_table[COLOR_BLACK];
                        *fgcolor = color_table[COLOR_WHITE];
                        break;
                case STYLE_SELECTED:
                        *bgcolor = color_table[COLOR_RED];
                        *fgcolor = color_table[COLOR_WHITE];
                        break;
                }
                break;
        case CHAR_ATTR_INDEX:
                *bgcolor = color_table[(attrs.val.index.bgcolor & 7) |
                    ((attrs.val.index.attr & CATTR_BRIGHT) ? 8 : 0)];
                *fgcolor = color_table[(attrs.val.index.fgcolor & 7) |
                    ((attrs.val.index.attr & CATTR_BRIGHT) ? 8 : 0)];
                break;
        case CHAR_ATTR_RGB:
                *bgcolor = 0xff000000 | attrs.val.rgb.bgcolor;
                *fgcolor = 0xff000000 | attrs.val.rgb.fgcolor;
                break;
        }
}

static void term_update_region(terminal_t *term, sysarg_t x, sysarg_t y,
    sysarg_t w, sysarg_t h)
{
        gfx_rect_t rect;
        gfx_rect_t nupdate;

        rect.p0.x = x;
        rect.p0.y = y;
        rect.p1.x = x + w;
        rect.p1.y = y + h;

        gfx_rect_envelope(&term->update, &rect, &nupdate);
        term->update = nupdate;
}

static void term_update_char(terminal_t *term, pixelmap_t *pixelmap,
    sysarg_t sx, sysarg_t sy, sysarg_t col, sysarg_t row)
{
        charfield_t *field =
            chargrid_charfield_at(term->backbuf, col, row);

        bool inverted = chargrid_cursor_at(term->backbuf, col, row);

        sysarg_t bx = sx + (col * FONT_WIDTH);
        sysarg_t by = sy + (row * FONT_SCANLINES);

        pixel_t bgcolor = 0;
        pixel_t fgcolor = 0;

        if (inverted)
                attrs_rgb(field->attrs, &fgcolor, &bgcolor);
        else
                attrs_rgb(field->attrs, &bgcolor, &fgcolor);

        // FIXME: Glyph type should be actually uint32_t
        //        for full UTF-32 coverage.

        uint16_t glyph = fb_font_glyph(field->ch, NULL);

        for (unsigned int y = 0; y < FONT_SCANLINES; y++) {
                pixel_t *dst = pixelmap_pixel_at(pixelmap, bx, by + y);
                pixel_t *dst_max = pixelmap_pixel_at(pixelmap, bx + FONT_WIDTH - 1, by + y);
                if (!dst || !dst_max)
                        continue;
                int count = FONT_WIDTH;
                while (count-- != 0) {
                        *dst++ = (fb_font[glyph][y] & (1 << count)) ? fgcolor : bgcolor;
                }
        }
        term_update_region(term, bx, by, FONT_WIDTH, FONT_SCANLINES);
}

static bool term_update_scroll(terminal_t *term, pixelmap_t *pixelmap,
    sysarg_t sx, sysarg_t sy)
{
        sysarg_t top_row = chargrid_get_top_row(term->frontbuf);

        if (term->top_row == top_row) {
                return false;
        }

        term->top_row = top_row;

        for (sysarg_t row = 0; row < term->rows; row++) {
                for (sysarg_t col = 0; col < term->cols; col++) {
                        charfield_t *front_field =
                            chargrid_charfield_at(term->frontbuf, col, row);
                        charfield_t *back_field =
                            chargrid_charfield_at(term->backbuf, col, row);
                        bool update = false;

                        if (front_field->ch != back_field->ch) {
                                back_field->ch = front_field->ch;
                                update = true;
                        }

                        if (!attrs_same(front_field->attrs, back_field->attrs)) {
                                back_field->attrs = front_field->attrs;
                                update = true;
                        }

                        front_field->flags &= ~CHAR_FLAG_DIRTY;

                        if (update) {
                                term_update_char(term, pixelmap, sx, sy, col, row);
                        }
                }
        }

        return true;
}

static bool term_update_cursor(terminal_t *term, pixelmap_t *pixelmap,
    sysarg_t sx, sysarg_t sy)
{
        bool update = false;

        sysarg_t front_col;
        sysarg_t front_row;
        chargrid_get_cursor(term->frontbuf, &front_col, &front_row);

        sysarg_t back_col;
        sysarg_t back_row;
        chargrid_get_cursor(term->backbuf, &back_col, &back_row);

        bool front_visibility =
            chargrid_get_cursor_visibility(term->frontbuf) &&
            term->is_focused;
        bool back_visibility =
            chargrid_get_cursor_visibility(term->backbuf);

        if (front_visibility != back_visibility) {
                chargrid_set_cursor_visibility(term->backbuf,
                    front_visibility);
                term_update_char(term, pixelmap, sx, sy, back_col, back_row);
                update = true;
        }

        if ((front_col != back_col) || (front_row != back_row)) {
                chargrid_set_cursor(term->backbuf, front_col, front_row);
                term_update_char(term, pixelmap, sx, sy, back_col, back_row);
                term_update_char(term, pixelmap, sx, sy, front_col, front_row);
                update = true;
        }

        return update;
}

static void term_update(terminal_t *term)
{
        pixelmap_t pixelmap;
        gfx_bitmap_alloc_t alloc;
        gfx_coord2_t pos;
        errno_t rc;

        rc = gfx_bitmap_get_alloc(term->bmp, &alloc);
        if (rc != EOK) {
                return;
        }

        fibril_mutex_lock(&term->mtx);
        pixelmap.width = term->w;
        pixelmap.height = term->h;
        pixelmap.data = alloc.pixels;

        bool update = false;
        sysarg_t sx = 0/*term->widget.hpos*/;
        sysarg_t sy = 0/*term->widget.vpos*/;

        if (term_update_scroll(term, &pixelmap, sx, sy)) {
                update = true;
        } else {
                for (sysarg_t y = 0; y < term->rows; y++) {
                        for (sysarg_t x = 0; x < term->cols; x++) {
                                charfield_t *front_field =
                                    chargrid_charfield_at(term->frontbuf, x, y);
                                charfield_t *back_field =
                                    chargrid_charfield_at(term->backbuf, x, y);
                                bool update = false;

                                if ((front_field->flags & CHAR_FLAG_DIRTY) ==
                                    CHAR_FLAG_DIRTY) {
                                        if (front_field->ch != back_field->ch) {
                                                back_field->ch = front_field->ch;
                                                update = true;
                                        }

                                        if (!attrs_same(front_field->attrs,
                                            back_field->attrs)) {
                                                back_field->attrs = front_field->attrs;
                                                update = true;
                                        }

                                        front_field->flags &= ~CHAR_FLAG_DIRTY;
                                }

                                if (update) {
                                        term_update_char(term, &pixelmap, sx, sy, x, y);
                                        update = true;
                                }
                        }
                }
        }

        if (term_update_cursor(term, &pixelmap, sx, sy))
                update = true;

        if (update) {
                pos.x = 4;
                pos.y = 26;
                (void) gfx_bitmap_render(term->bmp, &term->update, &pos);

                term->update.p0.x = 0;
                term->update.p0.y = 0;
                term->update.p1.x = 0;
                term->update.p1.y = 0;
        }

        fibril_mutex_unlock(&term->mtx);
}

static void term_repaint(terminal_t *term)
{
        pixelmap_t pixelmap;
        gfx_bitmap_alloc_t alloc;
        errno_t rc;

        rc = gfx_bitmap_get_alloc(term->bmp, &alloc);
        if (rc != EOK) {
                printf("Error getting bitmap allocation info.\n");
                return;
        }

        fibril_mutex_lock(&term->mtx);

        pixelmap.width = term->w;
        pixelmap.height = term->h;
        pixelmap.data = alloc.pixels;

        sysarg_t sx = 0;
        sysarg_t sy = 0;

        if (!term_update_scroll(term, &pixelmap, sx, sy)) {
                for (sysarg_t y = 0; y < term->rows; y++) {
                        for (sysarg_t x = 0; x < term->cols; x++) {
                                charfield_t *front_field =
                                    chargrid_charfield_at(term->frontbuf, x, y);
                                charfield_t *back_field =
                                    chargrid_charfield_at(term->backbuf, x, y);

                                back_field->ch = front_field->ch;
                                back_field->attrs = front_field->attrs;
                                front_field->flags &= ~CHAR_FLAG_DIRTY;

                                term_update_char(term, &pixelmap, sx, sy, x, y);
                        }
                }
        }

        term_update_cursor(term, &pixelmap, sx, sy);

        fibril_mutex_unlock(&term->mtx);
}

static errno_t term_open(con_srvs_t *srvs, con_srv_t *srv)
{
        return EOK;
}

static errno_t term_close(con_srv_t *srv)
{
        return EOK;
}

static errno_t term_read(con_srv_t *srv, void *buf, size_t size, size_t *nread)
{
        terminal_t *term = srv_to_terminal(srv);
        uint8_t *bbuf = buf;
        size_t pos = 0;

        /*
         * Read input from keyboard and copy it to the buffer.
         * We need to handle situation when wchar is split by 2 following
         * reads.
         */
        while (pos < size) {
                /* Copy to the buffer remaining characters. */
                while ((pos < size) && (term->char_remains_len > 0)) {
                        bbuf[pos] = term->char_remains[0];
                        pos++;

                        /* Unshift the array. */
                        for (size_t i = 1; i < term->char_remains_len; i++)
                                term->char_remains[i - 1] = term->char_remains[i];

                        term->char_remains_len--;
                }

                /* Still not enough? Then get another key from the queue. */
                if (pos < size) {
                        link_t *link = prodcons_consume(&term->input_pc);
                        cons_event_t *event = list_get_instance(link, cons_event_t, link);

                        /* Accept key presses of printable chars only. */
                        if (event->type == CEV_KEY && event->ev.key.type == KEY_PRESS &&
                            event->ev.key.c != 0) {
                                char32_t tmp[2] = {
                                        event->ev.key.c,
                                        0
                                };

                                wstr_to_str(term->char_remains, UTF8_CHAR_BUFFER_SIZE, tmp);
                                term->char_remains_len = str_size(term->char_remains);
                        }

                        free(event);
                }
        }

        *nread = size;
        return EOK;
}

static void term_write_char(terminal_t *term, wchar_t ch)
{
        sysarg_t updated = 0;

        fibril_mutex_lock(&term->mtx);

        switch (ch) {
        case '\n':
                updated = chargrid_newline(term->frontbuf);
                break;
        case '\r':
                break;
        case '\t':
                updated = chargrid_tabstop(term->frontbuf, 8);
                break;
        case '\b':
                updated = chargrid_backspace(term->frontbuf);
                break;
        default:
                updated = chargrid_putuchar(term->frontbuf, ch, true);
        }

        fibril_mutex_unlock(&term->mtx);

        if (updated > 1)
                term_update(term);
}

static errno_t term_write(con_srv_t *srv, void *data, size_t size, size_t *nwritten)
{
        terminal_t *term = srv_to_terminal(srv);

        size_t off = 0;
        while (off < size)
                term_write_char(term, str_decode(data, &off, size));

        *nwritten = size;
        return EOK;
}

static void term_sync(con_srv_t *srv)
{
        terminal_t *term = srv_to_terminal(srv);

        term_update(term);
}

static void term_clear(con_srv_t *srv)
{
        terminal_t *term = srv_to_terminal(srv);

        fibril_mutex_lock(&term->mtx);
        chargrid_clear(term->frontbuf);
        fibril_mutex_unlock(&term->mtx);

        term_update(term);
}

static void term_set_pos(con_srv_t *srv, sysarg_t col, sysarg_t row)
{
        terminal_t *term = srv_to_terminal(srv);

        fibril_mutex_lock(&term->mtx);
        chargrid_set_cursor(term->frontbuf, col, row);
        fibril_mutex_unlock(&term->mtx);

        term_update(term);
}

static errno_t term_get_pos(con_srv_t *srv, sysarg_t *col, sysarg_t *row)
{
        terminal_t *term = srv_to_terminal(srv);

        fibril_mutex_lock(&term->mtx);
        chargrid_get_cursor(term->frontbuf, col, row);
        fibril_mutex_unlock(&term->mtx);

        return EOK;
}

static errno_t term_get_size(con_srv_t *srv, sysarg_t *cols, sysarg_t *rows)
{
        terminal_t *term = srv_to_terminal(srv);

        fibril_mutex_lock(&term->mtx);
        *cols = term->cols;
        *rows = term->rows;
        fibril_mutex_unlock(&term->mtx);

        return EOK;
}

static errno_t term_get_color_cap(con_srv_t *srv, console_caps_t *caps)
{
        (void) srv;
        *caps = TERM_CAPS;

        return EOK;
}

static void term_set_style(con_srv_t *srv, console_style_t style)
{
        terminal_t *term = srv_to_terminal(srv);

        fibril_mutex_lock(&term->mtx);
        chargrid_set_style(term->frontbuf, style);
        fibril_mutex_unlock(&term->mtx);
}

static void term_set_color(con_srv_t *srv, console_color_t bgcolor,
    console_color_t fgcolor, console_color_attr_t attr)
{
        terminal_t *term = srv_to_terminal(srv);

        fibril_mutex_lock(&term->mtx);
        chargrid_set_color(term->frontbuf, bgcolor, fgcolor, attr);
        fibril_mutex_unlock(&term->mtx);
}

static void term_set_rgb_color(con_srv_t *srv, pixel_t bgcolor,
    pixel_t fgcolor)
{
        terminal_t *term = srv_to_terminal(srv);

        fibril_mutex_lock(&term->mtx);
        chargrid_set_rgb_color(term->frontbuf, bgcolor, fgcolor);
        fibril_mutex_unlock(&term->mtx);
}

static void term_set_cursor_visibility(con_srv_t *srv, bool visible)
{
        terminal_t *term = srv_to_terminal(srv);

        fibril_mutex_lock(&term->mtx);
        chargrid_set_cursor_visibility(term->frontbuf, visible);
        fibril_mutex_unlock(&term->mtx);

        term_update(term);
}

static errno_t term_get_event(con_srv_t *srv, cons_event_t *event)
{
        terminal_t *term = srv_to_terminal(srv);
        link_t *link = prodcons_consume(&term->input_pc);
        cons_event_t *ev = list_get_instance(link, cons_event_t, link);

        *event = *ev;
        free(ev);
        return EOK;
}

static void deinit_terminal(terminal_t *term)
{
        list_remove(&term->link);

        if (term->frontbuf)
                chargrid_destroy(term->frontbuf);

        if (term->backbuf)
                chargrid_destroy(term->backbuf);
}

void terminal_destroy(terminal_t *term)
{
        deinit_terminal(term);
        free(term);
}

static void terminal_queue_cons_event(terminal_t *term, cons_event_t *ev)
{
        /* Got key press/release event */
        cons_event_t *event =
            (cons_event_t *) malloc(sizeof(cons_event_t));
        if (event == NULL)
                return;

        *event = *ev;
        link_initialize(&event->link);

        prodcons_produce(&term->input_pc, &event->link);
}

/** Handle window close event. */
static void terminal_close_event(ui_window_t *window, void *arg)
{
        terminal_t *term = (terminal_t *) arg;

        (void) term;

        // XXX This is not really a clean way of terminating
        exit(0);
}

/** Handle window focus event. */
static void terminal_focus_event(ui_window_t *window, void *arg)
{
        terminal_t *term = (terminal_t *) arg;

        term->is_focused = true;
        term_update(term);
}

/** Handle window keyboard event */
static void terminal_kbd_event(ui_window_t *window, void *arg,
    kbd_event_t *kbd_event)
{
        terminal_t *term = (terminal_t *) arg;
        cons_event_t event;

        event.type = CEV_KEY;
        event.ev.key = *kbd_event;

        terminal_queue_cons_event(term, &event);
}

/** Handle window position event */
static void terminal_pos_event(ui_window_t *window, void *arg, pos_event_t *event)
{
        cons_event_t cevent;
        terminal_t *term = (terminal_t *) arg;

        sysarg_t sx = -term->off.x;
        sysarg_t sy = -term->off.y;

        if (event->type == POS_PRESS) {
                cevent.type = CEV_POS;
                cevent.ev.pos.type = event->type;
                cevent.ev.pos.pos_id = event->pos_id;
                cevent.ev.pos.btn_num = event->btn_num;

                cevent.ev.pos.hpos = (event->hpos - sx) / FONT_WIDTH;
                cevent.ev.pos.vpos = (event->vpos - sy) / FONT_SCANLINES;
                terminal_queue_cons_event(term, &cevent);
        }
}

/** Handle window unfocus event. */
static void terminal_unfocus_event(ui_window_t *window, void *arg)
{
        terminal_t *term = (terminal_t *) arg;

        term->is_focused = false;
        term_update(term);
}

static void term_connection(ipc_call_t *icall, void *arg)
{
        terminal_t *term = NULL;

        list_foreach(terms, link, terminal_t, cur) {
                if (cur->dsid == (service_id_t) ipc_get_arg2(icall)) {
                        term = cur;
                        break;
                }
        }

        if (term == NULL) {
                async_answer_0(icall, ENOENT);
                return;
        }

        if (!atomic_flag_test_and_set(&term->refcnt))
                chargrid_set_cursor_visibility(term->frontbuf, true);

        con_conn(icall, &term->srvs);
}

errno_t terminal_create(const char *display_spec, sysarg_t width,
    sysarg_t height, terminal_flags_t flags, terminal_t **rterm)
{
        terminal_t *term;
        gfx_bitmap_params_t params;
        ui_wnd_params_t wparams;
        gfx_rect_t rect;
        gfx_coord2_t off;
        gfx_rect_t wrect;
        errno_t rc;

        term = calloc(1, sizeof(terminal_t));
        if (term == NULL) {
                printf("Out of memory.\n");
                return ENOMEM;
        }

        link_initialize(&term->link);
        fibril_mutex_initialize(&term->mtx);
        atomic_flag_clear(&term->refcnt);

        prodcons_initialize(&term->input_pc);
        term->char_remains_len = 0;

        term->w = width;
        term->h = height;

        term->cols = width / FONT_WIDTH;
        term->rows = height / FONT_SCANLINES;

        term->frontbuf = NULL;
        term->backbuf = NULL;

        term->frontbuf = chargrid_create(term->cols, term->rows,
            CHARGRID_FLAG_NONE);
        if (!term->frontbuf) {
                printf("Error creating front buffer.\n");
                rc = ENOMEM;
                goto error;
        }

        term->backbuf = chargrid_create(term->cols, term->rows,
            CHARGRID_FLAG_NONE);
        if (!term->backbuf) {
                printf("Error creating back buffer.\n");
                rc = ENOMEM;
                goto error;
        }

        rect.p0.x = 0;
        rect.p0.y = 0;
        rect.p1.x = width;
        rect.p1.y = height;

        ui_wnd_params_init(&wparams);
        wparams.caption = "Terminal";
        if ((flags & tf_topleft) != 0)
                wparams.placement = ui_wnd_place_top_left;

        /*
         * Compute window rectangle such that application area corresponds
         * to rect
         */
        ui_wdecor_rect_from_app(&rect, &wrect);
        off = wrect.p0;
        gfx_rect_rtranslate(&off, &wrect, &wparams.rect);

        term->off = off;

        rc = ui_create(display_spec, &term->ui);
        if (rc != EOK) {
                printf("Error creating UI on %s.\n", display_spec);
                goto error;
        }

        rc = ui_window_create(term->ui, &wparams, &term->window);
        if (rc != EOK) {
                printf("Error creating window.\n");
                goto error;
        }

        term->gc = ui_window_get_gc(term->window);
        term->ui_res = ui_window_get_res(term->window);

        ui_window_set_cb(term->window, &terminal_window_cb, (void *) term);

        gfx_bitmap_params_init(&params);
        params.rect.p0.x = 0;
        params.rect.p0.y = 0;
        params.rect.p1.x = width;
        params.rect.p1.y = height;

        rc = gfx_bitmap_create(term->gc, &params, NULL, &term->bmp);
        if (rc != EOK) {
                printf("Error allocating screen bitmap.\n");
                goto error;
        }

        chargrid_clear(term->frontbuf);
        chargrid_clear(term->backbuf);
        term->top_row = 0;

        async_set_fallback_port_handler(term_connection, NULL);
        con_srvs_init(&term->srvs);
        term->srvs.ops = &con_ops;
        term->srvs.sarg = term;

        rc = loc_server_register(NAME);
        if (rc != EOK) {
                printf("Error registering server.\n");
                rc = EIO;
                goto error;
        }

        char vc[LOC_NAME_MAXLEN + 1];
        snprintf(vc, LOC_NAME_MAXLEN, "%s/%" PRIu64, NAMESPACE,
            task_get_id());

        rc = loc_service_register(vc, &term->dsid);
        if (rc != EOK) {
                printf("Error registering service.\n");
                rc = EIO;
                goto error;
        }

        list_append(&term->link, &terms);
        getterm(vc, "/app/bdsh");

        term->is_focused = true;

        term->update.p0.x = 0;
        term->update.p0.y = 0;
        term->update.p1.x = 0;
        term->update.p1.y = 0;

        term_repaint(term);

        *rterm = term;
        return EOK;
error:
        if (term->window != NULL)
                ui_window_destroy(term->window);
        if (term->ui != NULL)
                ui_destroy(term->ui);
        if (term->frontbuf != NULL)
                chargrid_destroy(term->frontbuf);
        if (term->backbuf != NULL)
                chargrid_destroy(term->backbuf);
        free(term);
        return rc;
}

/** @}
 */