Terminal: Das prompt, dprompt and dbanner (0.9.1)

- das-shell 0.1.0: the Das two-line bash prompt by default (replaces the
  PS1 of Void's skel .bashrc once), dprompt (Textual prompt builder with
  presets and live preview) and dbanner (SSH login banner editor: canvas
  tools, fields with values, widgets, das-banner service for cached ones,
  Das OS logo and tryzub pictures). Python tests in make test.
- das-server 0.3.0 depends on das-shell; the server installer mentions
  dprompt and dbanner; the desktop image includes it.
- run-qemu.sh forwards the guest's SSH to localhost:2222.
- Hardware fixes: Ventoy menu icon, boot menu titles "Das OS <version>".

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

srcpkgs/das-shell/files/python/das_shell/cli_banner.py

@@ -0,0 +1,154 @@
+"""dbanner: the banner shown at SSH login. Without arguments it opens the editor."""
+
+import json
+import os
+import subprocess
+import sys
+import time
+
+from . import banner, widgets
+from .cli import die, need_root, resolve, run_tui
+from .i18n import t
+
+PROG = "dbanner"
+SERVICE = "/etc/sv/das-banner"
+SERVICE_LINK = "/var/service/das-banner"
+
+
+def text(design, use_cache, color):
+    values = widgets.Values(design.get("vars"))
+    blocks = widgets.blocks(design, values, use_cache=use_cache)
+    return banner.render(design, values, blocks, color=color)
+
+
+def wants_login_banner(design):
+    if os.path.exists(banner.OFF_FILE) or os.path.exists(os.path.expanduser("~/.hushlogin")):
+        return False
+    if not sys.stdout.isatty():
+        return False
+    return bool(os.environ.get("SSH_TTY")) or bool(design.get("local"))
+
+
+def has_cached(design):
+    return any(w.get("enabled") is not False and widgets.mode_of(w) == "cached"
+               for w in design.get("widgets", []))
+
+
+def set_service(enabled):
+    """Enables the das-banner service (runit) that keeps cached widgets fresh."""
+    if not os.path.isdir(os.path.dirname(SERVICE_LINK)) or not os.path.isdir(SERVICE):
+        return False
+    if enabled and not os.path.lexists(SERVICE_LINK):
+        os.symlink(SERVICE, SERVICE_LINK)
+    elif not enabled and os.path.lexists(SERVICE_LINK):
+        os.remove(SERVICE_LINK)
+    return True
+
+
+def apply(design):
+    design = banner.normalize(design)
+    banner.save(design, banner.SYSTEM_FILE)
+    os.chmod(banner.SYSTEM_FILE, 0o644)
+    cached = has_cached(design)
+    service = set_service(cached)
+    if service and cached:
+        # The service fills the cache in a moment; this makes the first login see it too
+        subprocess.Popen([sys.executable, os.path.abspath(sys.argv[0]), "refresh"],
+                         stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL, start_new_session=True)
+    return cached and service
+
+
+USAGE = t("""Використання: dbanner [команда]
+  (без команди)          редактор банера з готовими варіантами
+  list                   готові банери, ваші чернетки й малюнки
+  show [НАЗВА|ФАЙЛ]      показати банер (типово — системний) зі свіжими даними
+       --no-color        без кольорів
+  apply НАЗВА|ФАЙЛ       зробити банером при вході по SSH (/etc/das/banner.json)
+  off | on               вимкнути або ввімкнути банер
+  refresh [--force]      оновити віджети з кешем (робить служба das-banner)
+Банер показується при вході по SSH; "local": true у файлі — і при вході в консоль.
+Окремий користувач вимикає його файлом ~/.hushlogin.""",
+          """Usage: dbanner [command]
+  (no command)           banner editor with ready-made designs
+  list                   ready-made banners, your drafts and pictures
+  show [NAME|FILE]       show a banner (default: the system one) with fresh data
+       --no-color        without colors
+  apply NAME|FILE        make it the SSH login banner (/etc/das/banner.json)
+  off | on               turn the banner off or on
+  refresh [--force]      update the cached widgets (the das-banner service does it)
+The banner is shown at SSH logins; "local": true in the file shows it on the
+console too. A user turns it off for themselves with ~/.hushlogin.""")
+
+
+def main(argv=None):
+    argv = sys.argv[1:] if argv is None else argv
+    if not argv:
+        from . import banner_app
+        return run_tui(PROG, banner_app.BannerApp)
+    cmd, args = argv[0], argv[1:]
+    flags = {a for a in args if a.startswith("--")}
+    args = [a for a in args if not a.startswith("--")]
+    try:
+        if cmd in ("-h", "--help", "help"):
+            print(USAGE)
+        elif cmd == "list":
+            print(t("Готові:", "Ready-made:"))
+            for name, title in banner.list_presets():
+                print(f"  {name:<14} {title}")
+            drafts = banner.list_drafts()
+            if drafts:
+                print(t("Чернетки:", "Drafts:"))
+                for name, path in drafts:
+                    print(f"  {name:<14} {path}")
+            print(t("Малюнки (вставляються в редакторі):", "Pictures (inserted in the editor):"))
+            for name, title, _ in banner.list_art():
+                print(f"  {name:<14} {title}")
+        elif cmd == "show":
+            if "--login" in flags:
+                design = banner.system_design()
+                if wants_login_banner(design):
+                    sys.stdout.write(text(design, use_cache=True, color=True))
+                    sys.stdout.flush()
+                # A hung widget thread must not hold the login
+                os._exit(0)
+            design = banner.load(args[0]) if args else banner.system_design()
+            color = "--no-color" not in flags and sys.stdout.isatty() or "--color" in flags
+            sys.stdout.write(text(design, use_cache=not args, color=color))
+        elif cmd == "apply":
+            if not args:
+                die(PROG, "вкажіть назву або файл", "name a design or a file")
+            spec = resolve(args[0])
+            design = banner.load(spec)
+            need_root(["apply", spec])
+            cached = apply(design)
+            print(t("Банер записано в /etc/das/banner.json, його видно при наступному вході по SSH.",
+                    "The banner is written to /etc/das/banner.json; it shows at the next SSH login."))
+            if cached:
+                print(t("Віджети з кешем оновлює служба das-banner (увімкнено).",
+                        "Cached widgets are updated by the das-banner service (enabled)."))
+        elif cmd in ("off", "on"):
+            need_root([cmd])
+            if cmd == "off":
+                open(banner.OFF_FILE, "w").close()
+            elif os.path.exists(banner.OFF_FILE):
+                os.remove(banner.OFF_FILE)
+            print(t("Банер вимкнено." if cmd == "off" else "Банер увімкнено.",
+                    "The banner is off." if cmd == "off" else "The banner is on."))
+        elif cmd == "refresh":
+            if "--loop" in flags:
+                while True:
+                    widgets.refresh(banner.system_design())
+                    time.sleep(60)
+            widgets.refresh(banner.system_design(), force="--force" in flags)
+        else:
+            die(PROG, f"невідома команда: {cmd}\n{USAGE}", f"unknown command: {cmd}\n{USAGE}", 2)
+    except FileNotFoundError as e:
+        die(PROG, f"не знайдено: {e.filename or e}", f"not found: {e.filename or e}")
+    except (ValueError, json.JSONDecodeError) as e:
+        die(PROG, f"помилка у файлі: {e}", f"bad file: {e}")
+    except PermissionError as e:
+        die(PROG, f"немає доступу: {e.filename}", f"permission denied: {e.filename}")
+    return 0
+
+if __name__ == "__main__":
+    sys.exit(main())