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, 168 insertions, 0 deletions

diff --git a/src/console/consoled-workspace.c b/src/console/consoled-workspace.c
new file mode 100644
index 0000000000..56344ef2cf
--- /dev/null
+++ b/src/console/consoled-workspace.c
@@ -0,0 +1,168 @@
+/*-*- 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 "grdev.h"
+#include "idev.h"
+#include "list.h"
+#include "macro.h"
+#include "util.h"
+
+int workspace_new(Workspace **out, Manager *m) {
+        _cleanup_(workspace_unrefp) Workspace *w = NULL;
+        int r;
+
+        assert(out);
+
+        w = new0(Workspace, 1);
+        if (!w)
+                return -ENOMEM;
+
+        w->ref = 1;
+        w->manager = m;
+        LIST_PREPEND(workspaces_by_manager, m->workspace_list, w);
+
+        r = terminal_new(&w->current, w);
+        if (r < 0)
+                return r;
+
+        *out = w;
+        w = NULL;
+        return 0;
+}
+
+static void workspace_cleanup(Workspace *w) {
+        Terminal *t;
+
+        assert(w);
+        assert(w->ref == 0);
+        assert(w->manager);
+        assert(!w->session_list);
+
+        w->current = NULL;
+        while ((t = w->terminal_list))
+                terminal_free(t);
+
+        LIST_REMOVE(workspaces_by_manager, w->manager->workspace_list, w);
+        free(w);
+}
+
+Workspace *workspace_ref(Workspace *w) {
+        assert(w);
+
+        ++w->ref;
+        return w;
+}
+
+Workspace *workspace_unref(Workspace *w) {
+        if (!w)
+                return NULL;
+
+        assert(w->ref > 0);
+
+        if (--w->ref == 0)
+                workspace_cleanup(w);
+
+        return NULL;
+}
+
+Workspace *workspace_attach(Workspace *w, Session *s) {
+        assert(w);
+        assert(s);
+
+        LIST_PREPEND(sessions_by_workspace, w->session_list, s);
+        workspace_refresh(w);
+        return workspace_ref(w);
+}
+
+Workspace *workspace_detach(Workspace *w, Session *s) {
+        assert(w);
+        assert(s);
+        assert(s->active_ws == w);
+
+        LIST_REMOVE(sessions_by_workspace, w->session_list, s);
+        workspace_refresh(w);
+        return workspace_unref(w);
+}
+
+void workspace_refresh(Workspace *w) {
+        uint32_t width, height;
+        Terminal *t;
+        Session *s;
+        Display *d;
+
+        assert(w);
+
+        width = 0;
+        height = 0;
+
+        /* find out minimum dimension of all attached displays */
+        LIST_FOREACH(sessions_by_workspace, s, w->session_list) {
+                LIST_FOREACH(displays_by_session, d, s->display_list) {
+                        assert(d->width > 0 && d->height > 0);
+
+                        if (width == 0 || d->width < width)
+                                width = d->width;
+                        if (height == 0 || d->height < height)
+                                height = d->height;
+                }
+        }
+
+        /* either both are zero, or none is zero */
+        assert(!(!width ^ !height));
+
+        /* update terminal-sizes if dimensions changed */
+        if (w->width != width || w->height != height) {
+                w->width = width;
+                w->height = height;
+
+                LIST_FOREACH(terminals_by_workspace, t, w->terminal_list)
+                        terminal_resize(t);
+
+                workspace_dirty(w);
+        }
+}
+
+void workspace_dirty(Workspace *w) {
+        Session *s;
+
+        assert(w);
+
+        LIST_FOREACH(sessions_by_workspace, s, w->session_list)
+                session_dirty(s);
+}
+
+void workspace_feed(Workspace *w, idev_data *data) {
+        assert(w);
+        assert(data);
+
+        terminal_feed(w->current, data);
+}
+
+bool workspace_draw(Workspace *w, const grdev_display_target *target) {
+        assert(w);
+        assert(target);
+
+        return terminal_draw(w->current, target);
+}