1 files changed, 94 insertions, 0 deletions
diff --git a/preview b/preview
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+#!/usr/bin/env python3
+# preview: boot dist/udt in real GRUB under QEMU, before root installs it.
+# Copyright (C) 2026 Danilo M. <danix@danix.xyz>
+# Licensed under the GNU General Public License v2 only.
+"""Boot the built theme in GRUB x86_64-efi under QEMU and OVMF.
+
+Usage: preview [--live] [WIDTHxHEIGHT]
+
+Default: screenshot to dist/preview.png, headless. --live opens a QEMU
+window instead, to move through the menu and try the console ('c').
+The mode defaults to 2560x1080. The menu entries are stand-ins.
+"""
+import shutil
+import socket
+import subprocess
+import sys
+import tempfile
+import time
+from pathlib import Path
+
+REPO = Path(__file__).resolve().parent
+THEME = REPO / "dist" / "udt"
+SHOT = REPO / "dist" / "preview.png"
+OVMF = Path("/usr/share/OVMF")
+MODULES = ("part_gpt part_msdos fat normal configfile all_video efi_gop gfxterm "
+           "gfxmenu png jpeg font true").split()
+BOOT_WAIT = 12  # ponytail: fixed wait for OVMF + GRUB; raise it if the shot is blank
+CFG = """\
+insmod all_video
+insmod gfxterm
+set gfxmode={mode},auto
+terminal_output gfxterm
+{fonts}
+set theme=($root)/boot/grub/themes/udt/theme.txt
+set timeout=30
+menuentry 'Slackware (preview)' --class slackware --class os {{ true }}
+submenu 'Advanced options for Slackware' {{ menuentry 'Recovery' {{ true }} }}
+menuentry 'UEFI Firmware Settings' --class efi {{ true }}
+"""
+
+
+def main():
+    args = sys.argv[1:]
+    live = "--live" in args
+    args = [a for a in args if a != "--live"]
+    mode = args[0] if args else "2560x1080"
+    xres, yres = mode.split("x")
+    if not (THEME / "theme.txt").exists():
+        sys.exit("preview: dist/udt missing; run ./build first")
+    with tempfile.TemporaryDirectory() as tmp:
+        tmp = Path(tmp)
+        root = tmp / "esp"
+        grub = root / "boot/grub"
+        (root / "EFI/BOOT").mkdir(parents=True)
+        shutil.copytree(THEME, grub / "themes/udt")
+        # grub-mkconfig writes one loadfont per .pf2 in the theme dir; do the same.
+        fonts = "\n".join(f"loadfont ($root)/boot/grub/themes/udt/{f.name}"
+                          for f in sorted(THEME.glob("*.pf2")))
+        (grub / "grub.cfg").write_text(CFG.format(mode=mode, fonts=fonts))
+        subprocess.run(["grub-mkimage", "-O", "x86_64-efi", "-p", "/boot/grub",
+                        "-o", str(root / "EFI/BOOT/BOOTX64.EFI"), *MODULES], check=True)
+        vars_fd = tmp / "vars.fd"
+        vars_fd.write_bytes((OVMF / "OVMF_VARS.fd").read_bytes())
+        mon = tmp / "mon.sock"
+        cmd = ["qemu-system-x86_64", "-machine", "q35", "-m", "512",
+               "-drive", f"if=pflash,format=raw,readonly=on,file={OVMF / 'OVMF_CODE.fd'}",
+               "-drive", f"if=pflash,format=raw,file={vars_fd}",
+               "-drive", f"file=fat:rw:{root},format=raw",
+               "-vga", "none", "-device", f"VGA,edid=on,xres={xres},yres={yres}"]
+        if live:
+            return subprocess.run(cmd).returncode
+        q = subprocess.Popen(cmd + ["-display", "none", "-monitor", f"unix:{mon},server,nowait"])
+        try:
+            time.sleep(BOOT_WAIT)
+            s = socket.socket(socket.AF_UNIX)
+            s.connect(str(mon))
+            ppm = tmp / "shot.ppm"
+            s.sendall(f"screendump {ppm}\n".encode())
+            for _ in range(50):  # the dump is written asynchronously
+                if ppm.exists() and ppm.stat().st_size:
+                    break
+                time.sleep(0.2)
+            time.sleep(0.5)
+            s.sendall(b"quit\n")
+            q.wait(timeout=10)
+        finally:
+            if q.poll() is None:
+                q.kill()
+        subprocess.run(["magick", str(ppm), str(SHOT)], check=True)
+    print(f"preview: {SHOT}")
+
+
+if __name__ == "__main__":
+    main()