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;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2016 Ludovic Courtès <ludo@gnu.org>
;;;
;;; 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 (rnrs io ports)
#:use-module (ice-9 match)
#:export (marionette?
make-marionette
marionette-eval
marionette-control
%qwerty-us-keystrokes
marionette-type))
;;; 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:" socket-directory "/monitor")
"-chardev" (string-append "socket,id=repl,path=" socket-directory
"/repl")
"-device" "virtio-serial"
"-device" "virtconsole,chardev=repl"))
(define (accept* port)
(match (select (list port) '() (list port) timeout)
(((port) () ())
(accept port))
(_
(error "timeout in 'accept'" port))))
(let ((monitor (socket AF_UNIX SOCK_STREAM 0))
(repl (socket AF_UNIX SOCK_STREAM 0)))
(bind monitor (file->sockaddr "monitor"))
(listen monitor 1)
(bind repl (file->sockaddr "repl"))
(listen repl 1)
(match (primitive-fork)
(0
(catch #t
(lambda ()
(close monitor)
(close repl)
(match command
((program . args)
(apply execl program program
(append args extra-options)))))
(lambda (key . args)
(print-exception (current-error-port)
(stack-ref (make-stack #t) 1)
key args)
(primitive-exit 1))))
(pid
(format #t "QEMU runs as PID ~a~%" pid)
(match (accept* monitor)
((monitor-conn . _)
(display "connected to QEMU's monitor\n")
(close-port monitor)
(wait-for-monitor-prompt monitor-conn)
(display "read QEMU monitor prompt\n")
(marionette (append command extra-options) pid
monitor-conn
;; The following 'accept' call connects immediately, but
;; we don't know whether the guest has connected until
;; we actually receive the 'ready' message.
(match (accept* repl)
((repl-conn . addr)
(display "connected to guest REPL\n")
(close-port repl)
;; Delay reception of the 'ready' message so that the
;; caller can already send monitor commands.
(delay
(match (read repl-conn)
('ready
(display "marionette is ready\n")
repl-conn))))))))))))
(define (marionette-eval exp marionette)
"Evaluate EXP in MARIONETTE's backdoor REPL. Return the result."
(match marionette
(($ <marionette> command pid monitor (= force repl))
(write exp repl)
(newline repl)
(read repl))))
(define (marionette-control command marionette)
"Run COMMAND in the QEMU monitor of MARIONETTE. COMMAND is a string such as
\"sendkey ctrl-alt-f1\" or \"screendump foo.ppm\" (info \"(qemu-doc)
pcsys_monitor\")."
(match marionette
(($ <marionette> _ _ monitor)
(display command monitor)
(newline monitor)
(wait-for-monitor-prompt monitor))))
(define %qwerty-us-keystrokes
;; Maps "special" characters to their keystrokes.
'((#\newline . "ret")
(#\space . "spc")
(#\- . "minus")
(#\+ . "shift-equal")
(#\* . "shift-8")
(#\= . "equal")
(#\? . "shift-slash")
(#\[ . "bracket_left")
(#\] . "bracket_right")
(#\( . "shift-9")
(#\) . "shift-0")
(#\/ . "slash")
(#\< . "less")
(#\> . "shift-less")
(#\. . "dot")
(#\, . "comma")
(#\; . "semicolon")
(#\bs . "backspace")
(#\tab . "tab")))
(define* (string->keystroke-commands str
#:optional
(keystrokes
%qwerty-us-keystrokes))
"Return a list of QEMU monitor commands to send the keystrokes corresponding
to STR. KEYSTROKES is an alist specifying a mapping from characters to
keystrokes."
(string-fold-right (lambda (chr result)
(cons (string-append "sendkey "
(or (assoc-ref keystrokes chr)
(string chr)))
result))
'()
str))
(define* (marionette-type str marionette
#:key (keystrokes %qwerty-us-keystrokes))
"Type STR on MARIONETTE's keyboard, using the KEYSTROKES alist to map characters
to actual keystrokes."
(for-each (cut marionette-control <> marionette)
(string->keystroke-commands str keystrokes)))
;;; marionette.scm ends here
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