#!/usr/bin/env bash
# 17-fix-rdp-postupdate.sh — re-apply RDP boot-survivability fixes (#611)
#
# After the 2026-09-05 update-reboot, fresh xrdp sessions died two ways:
#
# 1) sesman "waitforx: Timed out waiting for RandR outputs" -> "X server
#    could not be started" -> Jump shows error + black screen.
#    Root cause: xrdp 0.10.1 waitforx races xorgxrdp's deferred-RandR output
#    creation (~400ms after X start) and can go permanently blind; the
#    u2 security NMU also intermittently execs waitforx with EMPTY argv
#    (observed 2026-09-05 03:58:38) which the real binary rejects with a
#    usage error. FIX: wrapper at .../xrdp/waitforx that (a) defaults -d
#    from $DISPLAY when argv is empty, (b) forces a RandR query via
#    xrandr after the deferred window (deterministically materializes
#    outputs), then execs the pristine waitforx.real.
# 2) /etc/X11/Xsession.d/90xbrlapi runs /bin/xbrlapi in the FOREGROUND;
#    with brltty inactive (no BrlAPI socket) it hangs forever, so Xsession
#    never reaches startplasma-x11 -> connected-but-black session.
#    FIX: disable the hook (no braille hardware on this VM).
#
# Also verifies (does not fight) the #611 baseline: max_bpp=24,
# new_cursors=false (cursor black-box: Jump drops cursor alpha; core
# shadowless cursors + server-side cursor drawing).
#
# Idempotent; safe while a session is live. --restart-xrdp bounces only
# the front-end (sessions live in sesman/sesexec and survive).
#
# Usage: sudo ./17-fix-rdp-postupdate.sh [--restart-xrdp]
# Self-elevates. Tee a run log: ./17-fix-rdp-postupdate.sh 2>&1 | tee logs/17-fix-rdp-postupdate.out
set -euo pipefail
[ "$(id -u)" = 0 ] || exec sudo bash "$0" "$@"

WFX_DIR=/usr/lib/x86_64-linux-gnu/xrdp
WFX=$WFX_DIR/waitforx
XRDP_INI=/etc/xrdp/xrdp.ini
XSDD=/etc/X11/Xsession.d
LOG=${LOG:-/dev/stdout}

say() { echo "[17-fix] $*"; }

# --- 1. waitforx wrapper -------------------------------------------------
mkdir -p /var/log/xrdp-fix
if [ ! -f "$WFX.real" ]; then
    cp -a "$WFX" "$WFX.real"
    say "backed up pristine waitforx -> $WFX.real"
else
    say "pristine waitforx.real already present"
fi
cat > "$WFX" <<'SHIM'
#!/bin/bash
# xrdp 0.10.1 workaround (#611): default -d from DISPLAY when sesexec
# passes empty argv; force a RandR query past the deferred-output window
# before handing off to the real binary. Log to /var/log/xrdp-fix/.
D=/var/log/xrdp-fix/waitforx-invocations.log
echo "$(date '+%F %T') argc=$# argv:$(printf ' [%s]' "$@") DISPLAY=[$DISPLAY]" >> "$D"
if [ $# -eq 0 ]; then
    set -- -d "${DISPLAY:-:10}"
fi
timeout 5 xrandr -display "${2:-${DISPLAY:-:10}}" >/dev/null 2>&1 || true
exec /usr/lib/x86_64-linux-gnu/xrdp/waitforx.real "$@"
SHIM
chmod 755 "$WFX"
bash -n "$WFX" || { say "FATAL: shim syntax error"; exit 1; }
say "waitforx wrapper installed"

# --- 2. xbrlapi foreground hang ------------------------------------------
if [ -f "$XSDD/90xbrlapi" ]; then
    mv "$XSDD/90xbrlapi" "$XSDD/90xbrlapi.disabled"
    say "disabled $XSDD/90xbrlapi (foreground xbrlapi hang, no braille HW)"
else
    say "xbrlapi hook already disabled"
fi

# --- 3. xrdp.ini baseline -------------------------------------------------
grep -q '^max_bpp=24' "$XRDP_INI" || say "WARN: max_bpp=24 missing (expected from #611)"
if grep -q '^new_cursors=true' "$XRDP_INI"; then
    sed -i 's/^new_cursors=true/new_cursors=false/' "$XRDP_INI"
    say "set new_cursors=false (cursor black-box fix)"
else
    say "new_cursors already false (or absent)"
fi

# --- 4. optional front-end bounce ----------------------------------------
if [ "${1:-}" = "--restart-xrdp" ]; then
    systemctl restart xrdp
    say "xrdp front-end restarted (sessions unaffected)"
fi

say "done. Evidence: /var/log/xrdp-fix/ + /var/log/xrdp-sesman.log"