* gnu/build/marionette.scm (%qwerty-us-keystrokes): Use shit-comma and shift-dot for #\< and #\> because the "less" key doesn't work the same in "US intl." layouts.
		
			
				
	
	
		
			361 lines
		
	
	
	
		
			13 KiB
		
	
	
	
		
			Scheme
		
	
	
	
	
	
			
		
		
	
	
			361 lines
		
	
	
	
		
			13 KiB
		
	
	
	
		
			Scheme
		
	
	
	
	
	
| ;;; GNU Guix --- Functional package management for GNU
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| ;;; Copyright © 2016, 2017, 2018, 2019, 2020 Ludovic Courtès <ludo@gnu.org>
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| ;;; Copyright © 2018 Chris Marusich <cmmarusich@gmail.com>
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| ;;;
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| ;;; This file is part of GNU Guix.
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| ;;;
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| ;;; GNU Guix is free software; you can redistribute it and/or modify it
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| ;;; under the terms of the GNU General Public License as published by
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| ;;; the Free Software Foundation; either version 3 of the License, or (at
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| ;;; your option) any later version.
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| ;;;
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| ;;; GNU Guix is distributed in the hope that it will be useful, but
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| ;;; WITHOUT ANY WARRANTY; without even the implied warranty of
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| ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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| ;;; GNU General Public License for more details.
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| ;;;
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| ;;; You should have received a copy of the GNU General Public License
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| ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
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| 
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| (define-module (gnu build marionette)
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|   #:use-module (srfi srfi-9)
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|   #:use-module (srfi srfi-26)
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|   #:use-module (rnrs io ports)
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|   #:use-module (ice-9 match)
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|   #:use-module (ice-9 popen)
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|   #:export (marionette?
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|             make-marionette
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|             marionette-eval
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|             wait-for-file
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|             wait-for-tcp-port
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|             wait-for-unix-socket
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|             marionette-control
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|             marionette-screen-text
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|             wait-for-screen-text
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|             %qwerty-us-keystrokes
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|             marionette-type))
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| 
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| ;;; Commentary:
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| ;;;
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| ;;; Instrumentation tools for QEMU virtual machines (VMs).  A "marionette" is
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| ;;; essentially a VM (a QEMU instance) with its monitor connected to a
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| ;;; Unix-domain socket, and with a REPL inside the guest listening on a
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| ;;; virtual console, which is itself connected to the host via a Unix-domain
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| ;;; socket--these are the marionette's strings, connecting it to the almighty
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| ;;; puppeteer.
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| ;;;
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| ;;; Code:
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| 
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| (define-record-type <marionette>
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|   (marionette command pid monitor repl)
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|   marionette?
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|   (command    marionette-command)                 ;list of strings
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|   (pid        marionette-pid)                     ;integer
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|   (monitor    marionette-monitor)                 ;port
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|   (repl       %marionette-repl))                  ;promise of a port
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| 
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| (define-syntax-rule (marionette-repl marionette)
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|   (force (%marionette-repl marionette)))
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| 
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| (define* (wait-for-monitor-prompt port #:key (quiet? #t))
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|   "Read from PORT until we have seen all of QEMU's monitor prompt.  When
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| QUIET? is false, the monitor's output is written to the current output port."
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|   (define full-prompt
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|     (string->list "(qemu) "))
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| 
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|   (let loop ((prompt full-prompt)
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|              (matches '())
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|              (prefix  '()))
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|     (match prompt
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|       (()
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|        ;; It's useful to set QUIET? so we don't display the echo of our own
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|        ;; commands.
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|        (unless quiet?
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|          (for-each (lambda (line)
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|                      (format #t "qemu monitor: ~a~%" line))
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|                    (string-tokenize (list->string (reverse prefix))
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|                                     (char-set-complement (char-set #\newline))))))
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|       ((chr rest ...)
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|        (let ((read (read-char port)))
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|          (cond ((eqv? read chr)
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|                 (loop rest (cons read matches) prefix))
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|                ((eof-object? read)
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|                 (error "EOF while waiting for QEMU monitor prompt"
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|                        (list->string (reverse prefix))))
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|                (else
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|                 (loop full-prompt
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|                       '()
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|                       (cons read (append matches prefix))))))))))
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| 
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| (define* (make-marionette command
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|                           #:key (socket-directory "/tmp") (timeout 20))
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|   "Return a QEMU marionette--i.e., a virtual machine with open connections to the
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| QEMU monitor and to the guest's backdoor REPL."
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|   (define (file->sockaddr file)
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|     (make-socket-address AF_UNIX
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|                          (string-append socket-directory "/" file)))
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| 
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|   (define extra-options
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|     (list "-nographic"
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|           "-monitor" (string-append "unix:" socket-directory "/monitor")
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|           "-chardev" (string-append "socket,id=repl,path=" socket-directory
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|                                     "/repl")
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| 
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|           ;; See
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|           ;; <http://www.linux-kvm.org/page/VMchannel_Requirements#Invocation>.
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|           "-device" "virtio-serial"
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|           "-device" "virtserialport,chardev=repl,name=org.gnu.guix.port.0"))
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| 
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|   (define (accept* port)
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|     (match (select (list port) '() (list port) timeout)
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|       (((port) () ())
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|        (accept port))
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|       (_
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|        (error "timeout in 'accept'" port))))
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| 
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|   (let ((monitor (socket AF_UNIX SOCK_STREAM 0))
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|         (repl    (socket AF_UNIX SOCK_STREAM 0)))
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|     (bind monitor (file->sockaddr "monitor"))
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|     (listen monitor 1)
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|     (bind repl (file->sockaddr "repl"))
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|     (listen repl 1)
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| 
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|     (match (primitive-fork)
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|       (0
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|        (catch #t
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|          (lambda ()
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|            (close monitor)
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|            (close repl)
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|            (match command
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|              ((program . args)
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|               (apply execl program program
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|                      (append args extra-options)))))
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|          (lambda (key . args)
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|            (print-exception (current-error-port)
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|                             (stack-ref (make-stack #t) 1)
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|                             key args)
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|            (primitive-exit 1))))
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|       (pid
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|        (format #t "QEMU runs as PID ~a~%" pid)
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| 
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|        (match (accept* monitor)
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|          ((monitor-conn . _)
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|           (display "connected to QEMU's monitor\n")
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|           (close-port monitor)
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|           (wait-for-monitor-prompt monitor-conn)
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|           (display "read QEMU monitor prompt\n")
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| 
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|           (marionette (append command extra-options) pid
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|                       monitor-conn
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| 
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|                       ;; The following 'accept' call connects immediately, but
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|                       ;; we don't know whether the guest has connected until
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|                       ;; we actually receive the 'ready' message.
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|                       (match (accept* repl)
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|                         ((repl-conn . addr)
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|                          (display "connected to guest REPL\n")
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|                          (close-port repl)
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|                          ;; Delay reception of the 'ready' message so that the
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|                          ;; caller can already send monitor commands.
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|                          (delay
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|                            (match (read repl-conn)
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|                              ('ready
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|                               (display "marionette is ready\n")
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|                               repl-conn))))))))))))
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| 
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| (define (marionette-eval exp marionette)
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|   "Evaluate EXP in MARIONETTE's backdoor REPL.  Return the result."
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|   (match marionette
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|     (($ <marionette> command pid monitor (= force repl))
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|      (write exp repl)
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|      (newline repl)
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|      (read repl))))
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| 
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| (define* (wait-for-file file marionette
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|                         #:key (timeout 10) (read 'read))
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|   "Wait until FILE exists in MARIONETTE; READ its content and return it.  If
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| FILE has not shown up after TIMEOUT seconds, raise an error."
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|   (match (marionette-eval
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|           `(let loop ((i ,timeout))
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|              (cond ((file-exists? ,file)
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|                     (cons 'success (call-with-input-file ,file ,read)))
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|                    ((> i 0)
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|                     (sleep 1)
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|                     (loop (- i 1)))
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|                    (else
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|                     'failure)))
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|           marionette)
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|     (('success . result)
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|      result)
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|     ('failure
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|      (error "file didn't show up" file))))
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| 
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| (define* (wait-for-tcp-port port marionette
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|                             #:key (timeout 20))
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|   "Wait for up to TIMEOUT seconds for PORT to accept connections in
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| MARIONETTE.  Raise an error on failure."
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|   ;; Note: The 'connect' loop has to run within the guest because, when we
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|   ;; forward ports to the host, connecting to the host never raises
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|   ;; ECONNREFUSED.
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|   (match (marionette-eval
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|           `(begin
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|              (let ((sock (socket PF_INET SOCK_STREAM 0)))
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|                (let loop ((i 0))
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|                  (catch 'system-error
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|                    (lambda ()
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|                      (connect sock AF_INET INADDR_LOOPBACK ,port)
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|                      (close-port sock)
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|                      'success)
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|                    (lambda args
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|                      (if (< i ,timeout)
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|                          (begin
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|                            (sleep 1)
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|                            (loop (+ 1 i)))
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|                          'failure))))))
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|           marionette)
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|     ('success #t)
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|     ('failure
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|      (error "nobody's listening on port" port))))
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| 
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| (define* (wait-for-unix-socket file-name marionette
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|                                 #:key (timeout 20))
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|   "Wait for up to TIMEOUT seconds for FILE-NAME, a Unix domain socket, to
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| accept connections in MARIONETTE.  Raise an error on failure."
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|   (match (marionette-eval
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|           `(begin
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|              (let ((sock (socket PF_UNIX SOCK_STREAM 0)))
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|                (let loop ((i 0))
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|                  (catch 'system-error
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|                    (lambda ()
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|                      (connect sock AF_UNIX ,file-name)
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|                      (close-port sock)
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|                      'success)
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|                    (lambda args
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|                      (if (< i ,timeout)
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|                          (begin
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|                            (sleep 1)
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|                            (loop (+ 1 i)))
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|                          'failure))))))
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|           marionette)
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|     ('success #t)
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|     ('failure
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|      (error "nobody's listening on unix domain socket" file-name))))
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| 
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| (define (marionette-control command marionette)
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|   "Run COMMAND in the QEMU monitor of MARIONETTE.  COMMAND is a string such as
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| \"sendkey ctrl-alt-f1\" or \"screendump foo.ppm\" (info \"(qemu-doc)
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| pcsys_monitor\")."
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|   (match marionette
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|     (($ <marionette> _ _ monitor)
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|      (display command monitor)
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|      (newline monitor)
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|      ;; The "quit" command terminates QEMU immediately, with no output.
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|      (unless (string=? command "quit") (wait-for-monitor-prompt monitor)))))
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| 
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| (define* (marionette-screen-text marionette
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|                                  #:key
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|                                  (ocrad "ocrad"))
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|   "Take a screenshot of MARIONETTE, perform optical character
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| recognition (OCR), and return the text read from the screen as a string.  Do
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| this by invoking OCRAD (file name for GNU Ocrad's command)"
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|   (define (random-file-name)
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|     (string-append "/tmp/marionette-screenshot-"
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|                    (number->string (random (expt 2 32)) 16)
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|                    ".ppm"))
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| 
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|   (let ((image (random-file-name)))
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|     (dynamic-wind
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|       (const #t)
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|       (lambda ()
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|         (marionette-control (string-append "screendump " image)
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|                             marionette)
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| 
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|         ;; Tell Ocrad to invert the image colors (make it black on white) and
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|         ;; to scale the image up, which significantly improves the quality of
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|         ;; the result.  In spite of this, be aware that OCR confuses "y" and
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|         ;; "V" and sometimes erroneously introduces white space.
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|         (let* ((pipe (open-pipe* OPEN_READ ocrad
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|                                  "-i" "-s" "10" image))
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|                (text (get-string-all pipe)))
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|           (unless (zero? (close-pipe pipe))
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|             (error "'ocrad' failed" ocrad))
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|           text))
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|       (lambda ()
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|         (false-if-exception (delete-file image))))))
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| 
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| (define* (wait-for-screen-text marionette predicate
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|                                #:key (timeout 30) (ocrad "ocrad"))
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|   "Wait for TIMEOUT seconds or until the screen text on MARIONETTE matches
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| PREDICATE, whichever comes first.  Raise an error when TIMEOUT is exceeded."
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|   (define start
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|     (car (gettimeofday)))
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| 
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|   (define end
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|     (+ start timeout))
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| 
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|   (let loop ()
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|     (if (> (car (gettimeofday)) end)
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|         (error "'wait-for-screen-text' timeout" predicate)
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|         (or (predicate (marionette-screen-text marionette #:ocrad ocrad))
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|             (begin
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|               (sleep 1)
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|               (loop))))))
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| 
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| (define %qwerty-us-keystrokes
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|   ;; Maps "special" characters to their keystrokes.
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|   '((#\newline . "ret")
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|     (#\space . "spc")
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|     (#\- . "minus")
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|     (#\+ . "shift-equal")
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|     (#\* . "shift-8")
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|     (#\= . "equal")
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|     (#\? . "shift-slash")
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|     (#\[ . "bracket_left")
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|     (#\] . "bracket_right")
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|     (#\{ . "shift-bracket_left")
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|     (#\} . "shift-bracket_right")
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|     (#\( . "shift-9")
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|     (#\) . "shift-0")
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|     (#\/ . "slash")
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|     (#\< . "shift-comma")
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|     (#\> . "shift-dot")
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|     (#\. . "dot")
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|     (#\, . "comma")
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|     (#\; . "semicolon")
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|     (#\' . "apostrophe")
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|     (#\" . "shift-apostrophe")
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|     (#\` . "grave_accent")
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|     (#\bs . "backspace")
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|     (#\tab . "tab")))
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| 
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| (define (character->keystroke chr keystrokes)
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|   "Return the keystroke for CHR according to the keyboard layout defined by
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| KEYSTROKES."
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|   (if (char-set-contains? char-set:upper-case chr)
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|       (string-append "shift-" (string (char-downcase chr)))
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|       (or (assoc-ref keystrokes chr)
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|           (string chr))))
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| 
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| (define* (string->keystroke-commands str
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|                                      #:optional
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|                                      (keystrokes
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|                                       %qwerty-us-keystrokes))
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|   "Return a list of QEMU monitor commands to send the keystrokes corresponding
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| to STR.  KEYSTROKES is an alist specifying a mapping from characters to
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| keystrokes."
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|   (string-fold-right (lambda (chr result)
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|                        (cons (string-append
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|                               "sendkey "
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|                               (character->keystroke chr keystrokes))
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|                              result))
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|                      '()
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|                      str))
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| 
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| (define* (marionette-type str marionette
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|                           #:key (keystrokes %qwerty-us-keystrokes))
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|   "Type STR on MARIONETTE's keyboard, using the KEYSTROKES alist to map characters
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| to actual keystrokes."
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|   (for-each (cut marionette-control <> marionette)
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|             (string->keystroke-commands str keystrokes)))
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| 
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| ;;; marionette.scm ends here
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