console: add user console daemon

This adds a first draft of systemd-consoled. This is still missing a lot
of features and does some rather primitive rendering. However, it shows
the direction this code is going and serves as basis for further testing.

The systemd-consoled binary should be run as `systemd --user' unit. It
automatically picks up any session marked as Desktop=SYSTEMD-CONSOLE.
Therefore, you can use any login-manager you want (ranging from /bin/login
to gdm) to create sessions for systemd-consoled. However, the sessions
managers must be prepared to set the Desktop= variable properly.

The user-session is called `systemd-console', only the daemon providing
the terminal environment is called `systemd-consoled' (mind the 'd').

So far, only a single terminal session is provided on each opened
user-session. However, we support multiple user-sessions (even across
multiple seats) just fine. In the future, the workspace logic will get
extended so you can have multiple terminal sessions in a single
user-session for easier access.

Note that this is still experimental! Instructions on how to run it will
follow shortly.

1 files changed, 360 insertions, 0 deletions

diff --git a/src/console/consoled-terminal.c b/src/console/consoled-terminal.c
new file mode 100644
index 0000000000..d091579aa5
--- /dev/null
+++ b/src/console/consoled-terminal.c
@@ -0,0 +1,360 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2014 David Herrmann <dh.herrmann@gmail.com>
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <errno.h>
+#include <inttypes.h>
+#include <stdlib.h>
+#include "consoled.h"
+#include "list.h"
+#include "macro.h"
+#include "util.h"
+
+static int terminal_write_fn(term_screen *screen, void *userdata, const void *buf, size_t size) {
+        Terminal *t = userdata;
+        int r;
+
+        if (t->pty) {
+                r = pty_write(t->pty, buf, size);
+                if (r < 0)
+                        return log_oom();
+        }
+
+        return 0;
+}
+
+static int terminal_pty_fn(Pty *pty, void *userdata, unsigned int event, const void *ptr, size_t size) {
+        Terminal *t = userdata;
+        int r;
+
+        switch (event) {
+        case PTY_CHILD:
+                log_debug("PTY child exited");
+                t->pty = pty_unref(t->pty);
+                break;
+        case PTY_DATA:
+                r = term_screen_feed_text(t->screen, ptr, size);
+                if (r < 0)
+                        log_error("Cannot update screen state: %s", strerror(-r));
+
+                workspace_dirty(t->workspace);
+                break;
+        }
+
+        return 0;
+}
+
+int terminal_new(Terminal **out, Workspace *w) {
+        _cleanup_(terminal_freep) Terminal *t = NULL;
+        int r;
+
+        assert(w);
+
+        t = new0(Terminal, 1);
+        if (!t)
+                return -ENOMEM;
+
+        t->workspace = w;
+        LIST_PREPEND(terminals_by_workspace, w->terminal_list, t);
+
+        r = term_parser_new(&t->parser, true);
+        if (r < 0)
+                return r;
+
+        r = term_screen_new(&t->screen, terminal_write_fn, t, NULL, NULL);
+        if (r < 0)
+                return r;
+
+        r = term_screen_set_answerback(t->screen, "systemd-console");
+        if (r < 0)
+                return r;
+
+        if (out)
+                *out = t;
+        t = NULL;
+        return 0;
+}
+
+Terminal *terminal_free(Terminal *t) {
+        if (!t)
+                return NULL;
+
+        assert(t->workspace);
+
+        if (t->pty) {
+                (void)pty_signal(t->pty, SIGHUP);
+                pty_close(t->pty);
+                pty_unref(t->pty);
+        }
+        term_screen_unref(t->screen);
+        term_parser_free(t->parser);
+        LIST_REMOVE(terminals_by_workspace, t->workspace->terminal_list, t);
+        free(t);
+
+        return NULL;
+}
+
+void terminal_resize(Terminal *t) {
+        uint32_t width, height, fw, fh;
+        int r;
+
+        assert(t);
+
+        width = t->workspace->width;
+        height = t->workspace->height;
+        fw = unifont_get_width(t->workspace->manager->uf);
+        fh = unifont_get_height(t->workspace->manager->uf);
+
+        width = (fw > 0) ? width / fw : 0;
+        height = (fh > 0) ? height / fh : 0;
+
+        if (t->pty) {
+                r = pty_resize(t->pty, width, height);
+                if (r < 0)
+                        log_error("Cannot resize pty: %s", strerror(-r));
+        }
+
+        r = term_screen_resize(t->screen, width, height);
+        if (r < 0)
+                log_error("Cannot resize screen: %s", strerror(-r));
+}
+
+void terminal_run(Terminal *t) {
+        pid_t pid;
+
+        assert(t);
+
+        if (t->pty)
+                return;
+
+        pid = pty_fork(&t->pty,
+                       t->workspace->manager->event,
+                       terminal_pty_fn,
+                       t,
+                       term_screen_get_width(t->screen),
+                       term_screen_get_height(t->screen));
+        if (pid < 0) {
+                log_error("Cannot fork PTY: %s", strerror(-pid));
+                return;
+        } else if (pid == 0) {
+                /* child */
+
+                char **argv = (char*[]){
+                        (char*)getenv("SHELL") ? : (char*)_PATH_BSHELL,
+                        NULL
+                };
+
+                setenv("TERM", "xterm-256color", 1);
+                setenv("COLORTERM", "systemd-console", 1);
+
+                execve(argv[0], argv, environ);
+                log_error("Cannot exec %s (%d): %m", argv[0], -errno);
+                _exit(1);
+        }
+}
+
+static void terminal_feed_keyboard(Terminal *t, idev_data *data) {
+        idev_data_keyboard *kdata = &data->keyboard;
+        int r;
+
+        if (!data->resync && (kdata->value == 1 || kdata->value == 2)) {
+                assert_cc(TERM_KBDMOD_CNT == (int)IDEV_KBDMOD_CNT);
+                assert_cc(TERM_KBDMOD_IDX_SHIFT == (int)IDEV_KBDMOD_IDX_SHIFT &&
+                          TERM_KBDMOD_IDX_CTRL == (int)IDEV_KBDMOD_IDX_CTRL &&
+                          TERM_KBDMOD_IDX_ALT == (int)IDEV_KBDMOD_IDX_ALT &&
+                          TERM_KBDMOD_IDX_LINUX == (int)IDEV_KBDMOD_IDX_LINUX &&
+                          TERM_KBDMOD_IDX_CAPS == (int)IDEV_KBDMOD_IDX_CAPS);
+
+                r = term_screen_feed_keyboard(t->screen,
+                                              kdata->keysyms,
+                                              kdata->n_syms,
+                                              kdata->ascii,
+                                              kdata->codepoints,
+                                              kdata->mods);
+                if (r < 0)
+                        log_error("Cannot feed keyboard data to screen: %s",
+                                  strerror(-r));
+        }
+}
+
+void terminal_feed(Terminal *t, idev_data *data) {
+        switch (data->type) {
+        case IDEV_DATA_KEYBOARD:
+                terminal_feed_keyboard(t, data);
+                break;
+        }
+}
+
+static void terminal_fill(uint8_t *dst,
+                          uint32_t width,
+                          uint32_t height,
+                          uint32_t stride,
+                          uint32_t value) {
+        uint32_t i, j, *px;
+
+        for (j = 0; j < height; ++j) {
+                px = (uint32_t*)dst;
+
+                for (i = 0; i < width; ++i)
+                        *px++ = value;
+
+                dst += stride;
+        }
+}
+
+static void terminal_blend(uint8_t *dst,
+                           uint32_t width,
+                           uint32_t height,
+                           uint32_t dst_stride,
+                           const uint8_t *src,
+                           uint32_t src_stride,
+                           uint32_t fg,
+                           uint32_t bg) {
+        uint32_t i, j, *px;
+
+        for (j = 0; j < height; ++j) {
+                px = (uint32_t*)dst;
+
+                for (i = 0; i < width; ++i) {
+                        if (!src || src[i / 8] & (1 << (7 - i % 8)))
+                                *px = fg;
+                        else
+                                *px = bg;
+
+                        ++px;
+                }
+
+                src += src_stride;
+                dst += dst_stride;
+        }
+}
+
+typedef struct {
+        const grdev_display_target *target;
+        unifont *uf;
+        uint32_t cell_width;
+        uint32_t cell_height;
+        bool dirty;
+} TerminalDrawContext;
+
+static int terminal_draw_cell(term_screen *screen,
+                              void *userdata,
+                              unsigned int x,
+                              unsigned int y,
+                              const term_attr *attr,
+                              const uint32_t *ch,
+                              size_t n_ch,
+                              unsigned int ch_width) {
+        TerminalDrawContext *ctx = userdata;
+        const grdev_display_target *target = ctx->target;
+        grdev_fb *fb = target->back;
+        uint32_t xpos, ypos, width, height;
+        uint32_t fg, bg;
+        unifont_glyph g;
+        uint8_t *dst;
+        int r;
+
+        if (n_ch > 0) {
+                r = unifont_lookup(ctx->uf, &g, *ch);
+                if (r < 0)
+                        r = unifont_lookup(ctx->uf, &g, 0xfffd);
+                if (r < 0)
+                        unifont_fallback(&g);
+        }
+
+        xpos = x * ctx->cell_width;
+        ypos = y * ctx->cell_height;
+
+        if (xpos >= fb->width || ypos >= fb->height)
+                return 0;
+
+        width = MIN(fb->width - xpos, ctx->cell_width * ch_width);
+        height = MIN(fb->height - ypos, ctx->cell_height);
+
+        term_attr_to_argb32(attr, &fg, &bg, NULL);
+
+        ctx->dirty = true;
+
+        dst = fb->maps[0];
+        dst += fb->strides[0] * ypos + sizeof(uint32_t) * xpos;
+
+        if (n_ch < 1) {
+                terminal_fill(dst,
+                              width,
+                              height,
+                              fb->strides[0],
+                              bg);
+        } else {
+                if (width > g.width)
+                        terminal_fill(dst + sizeof(uint32_t) * g.width,
+                                      width - g.width,
+                                      height,
+                                      fb->strides[0],
+                                      bg);
+                if (height > g.height)
+                        terminal_fill(dst + fb->strides[0] * g.height,
+                                      width,
+                                      height - g.height,
+                                      fb->strides[0],
+                                      bg);
+
+                terminal_blend(dst,
+                               width,
+                               height,
+                               fb->strides[0],
+                               g.data,
+                               g.stride,
+                               fg,
+                               bg);
+        }
+
+        return 0;
+}
+
+bool terminal_draw(Terminal *t, const grdev_display_target *target) {
+        TerminalDrawContext ctx = { };
+        uint64_t age;
+
+        assert(t);
+        assert(target);
+
+        /* start up terminal on first frame */
+        terminal_run(t);
+
+        ctx.target = target;
+        ctx.uf = t->workspace->manager->uf;
+        ctx.cell_width = unifont_get_width(ctx.uf);
+        ctx.cell_height = unifont_get_height(ctx.uf);
+        ctx.dirty = false;
+
+        if (target->front) {
+                /* if the frontbuffer is new enough, no reason to redraw */
+                age = term_screen_get_age(t->screen);
+                if (age != 0 && age <= target->front->data.u64)
+                        return false;
+        } else {
+                /* force flip if no frontbuffer is set, yet */
+                ctx.dirty = true;
+        }
+
+        term_screen_draw(t->screen, terminal_draw_cell, &ctx, &target->back->data.u64);
+
+        return ctx.dirty;
+}