;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2016-2022, 2024 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2018 Chris Marusich <cmmarusich@gmail.com>
;;; Copyright © 2022, 2023 Maxim Cournoyer <maxim.cournoyer@gmail.com>
;;; Copyright © 2023 Bruno Victal <mirai@makinata.eu>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix 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 General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.

(define-module (gnu build marionette)
  #:use-module (srfi srfi-9)
  #:use-module (srfi srfi-26)
  #:use-module (srfi srfi-64)
  #:use-module (srfi srfi-71)
  #:use-module (rnrs io ports)
  #:use-module (ice-9 match)
  #:use-module (ice-9 popen)
  #:use-module (ice-9 regex)
  #:export (marionette?
            marionette-pid
            make-marionette
            marionette-eval
            wait-for-file
            wait-for-tcp-port
            wait-for-unix-socket
            marionette-control
            wait-for-screen-text
            %default-ocrad-arguments
            %qwerty-us-keystrokes
            marionette-type

            system-test-runner
            qemu-command))

;;; Commentary:
;;;
;;; Instrumentation tools for QEMU virtual machines (VMs).  A "marionette" is
;;; essentially a VM (a QEMU instance) with its monitor connected to a
;;; Unix-domain socket, and with a REPL inside the guest listening on a
;;; virtual console, which is itself connected to the host via a Unix-domain
;;; socket--these are the marionette's strings, connecting it to the almighty
;;; puppeteer.
;;;
;;; Code:

(define-record-type <marionette>
  (marionette command pid monitor repl)
  marionette?
  (command    marionette-command)                 ;list of strings
  (pid        marionette-pid)                     ;integer
  (monitor    marionette-monitor)                 ;port
  (repl       %marionette-repl))                  ;promise of a port

(define-syntax-rule (marionette-repl marionette)
  (force (%marionette-repl marionette)))

(define* (wait-for-monitor-prompt port #:key (quiet? #t))
  "Read from PORT until we have seen all of QEMU's monitor prompt.  When
QUIET? is false, the monitor's output is written to the current output port."
  (define full-prompt
    (string->list "(qemu) "))

  (let loop ((prompt full-prompt)
             (matches '())
             (prefix  '()))
    (match prompt
      (()
       ;; It's useful to set QUIET? so we don't display the echo of our own
       ;; commands.
       (unless quiet?
         (for-each (lambda (line)
                     (format #t "qemu monitor: ~a~%" line))
                   (string-tokenize (list->string (reverse prefix))
                                    (char-set-complement (char-set #\newline))))))
      ((chr rest ...)
       (let ((read (read-char port)))
         (cond ((eqv? read chr)
                (loop rest (cons read matches) prefix))
               ((eof-object? read)
                (error "EOF while waiting for QEMU monitor prompt"
                       (list->string (reverse prefix))))
               (else
                (loop full-prompt
                      '()
                      (cons read (append matches prefix))))))))))

(define* (make-marionette command
                          #:key (socket-directory "/tmp") (timeout 20))
  "Return a QEMU marionette--i.e., a virtual machine with open connections to the
QEMU monitor and to the guest's backdoor REPL."
  (define (file->sockaddr file)
    (make-socket-address AF_UNIX
                         (string-append socket-directory "/" file)))

  (define extra-options
    (list "-nographic"
          "-monitor" (string-append "unix:" soc