;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2016, 2017 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2017 Clément Lassieur <clement@lassieur.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 tests ssh)
  #:use-module (gnu tests)
  #:use-module (gnu system)
  #:use-module (gnu system vm)
  #:use-module (gnu services)
  #:use-module (gnu services ssh)
  #:use-module (gnu services networking)
  #:use-module (gnu packages ssh)
  #:use-module (guix gexp)
  #:use-module (guix store)
  #:export (%test-openssh
            %test-dropbear))

(define* (run-ssh-test name ssh-service pid-file #:key (sftp? #f))
  "Run a test of an OS running SSH-SERVICE, which writes its PID to PID-FILE.
SSH-SERVICE must be configured to listen on port 22 and to allow for root and
empty-password logins.

When SFTP? is true, run an SFTP server test."
  (define os
    (marionette-operating-system
     (simple-operating-system (dhcp-client-service) ssh-service)
     #:imported-modules '((gnu services herd)
                          (guix combinators))))
  (define vm
    (virtual-machine
     (operating-system os)
     (port-forwardings '((2222 . 22)))))

  (define test
    (with-imported-modules '((gnu build marionette))
      #~(begin
          (eval-when (expand load eval)
            ;; Prepare to use Guile-SSH.
            (set! %load-path
              (cons (string-append #+guile-ssh "/share/guile/site/"
                                   (effective-version))
                    %load-path)))

          (use-modules (gnu build marionette)
                       (srfi srfi-26)
                       (srfi srfi-64)
                       (ice-9 match)
                       (ssh session)
                       (ssh auth)
                       (ssh channel)
                       (ssh sftp))

          (define marionette
            ;; Enable TCP forwarding of the guest's port 22.
            (make-marionette (list #$vm)))

          (define (make-session-for-test)
            "Make a session with predefined parameters for a test."
            (make-session #:user "root"
                          #:port 2222
                          #:host "localhost"
                          #:log-verbosity 'protocol))

          (define (call-with-connected-session proc)
            "Call the one-argument procedure PROC with a freshly created and
connected SSH session object, return the result of the procedure call.  The
session is disconnected when the PROC is finished."
            (let ((session (make-session-for-test)))
              (dynamic-wind
                (lambda ()
                  (let ((result (connect! session)))
                    (unless (equal? result 'ok)
                      (error "Could not connect to a server"
                             session result))))
                (lambda () (proc session))
                (lambda () (disconnect! session)))))

          (define (call-with-connected-session/auth proc)
            "Make an authenticated session.  We should be able to connect as
root with an empty password."
            (call-with-connected-session
             (lambda (session)
               ;; Try the simple authentication methods.  Dropbear requires
               ;; 'none' when there are no passwords, whereas OpenSSH accepts
               ;; 'password' with an empty password.
               (let loop ((methods (list (cut userauth-password! <> "")
                                         (cut userauth-none! <>))))
                 (match methods
                   (()
                    (error "all the authentication methods failed"))
                   ((auth rest ...)
                    (match (pk 'auth (auth session))
                      ('success
                       (proc session))
                      ('denied
                       (loop rest)))))))))

          (mkdir #$output)
          (chdir #$output)

          (test-begin "ssh-daemon")

          ;; Wait for sshd to be up and running.
          (test-eq "service running"
            'running!
            (marionette-eval
             '(begin
                (use-modules (gnu services herd))
                (start-service 'ssh-daemon)
                'running!)
             marionette))

          ;; Check sshd's PID file.
          (test-equal "sshd PID"
            (wait-for-file #$pid-file marionette)
            (marionette-eval
             '(begin
                (use-modules (gnu services herd)
                             (srfi srfi-1))

                (live-service-running
                 (find (lambda (live)
                         (memq 'ssh-daemon
                               (live-service-provision live)))
                       (current-services))))
             marionette))

          ;; Connect to the guest over SSH.  Make sure we can run a shell
          ;; command there.
          (test-equal "shell command"
            'hello
            (call-with-connected-session/auth
             (lambda (session)
               ;; FIXME: 'get-server-public-key' segfaults.
               ;; (get-server-public-key session)
               (let ((channel (make-channel session)))
                 (channel-open-session channel)
                 (channel-request-exec channel "echo hello > /root/witness")
                 (and (zero? (channel-get-exit-status channel))
                      (wait-for-file "/root/witness" marionette))))))

          ;; Connect to the guest over SFTP.  Make sure we can write and
          ;; read a file there.
          (unless #$sftp?
            (test-skip 1))
          (test-equal "SFTP file writing and reading"
            'hello
            (call-with-connected-session/auth
             (lambda (session)
               (let ((sftp-session (make-sftp-session session))
                     (witness "/root/sftp-witness"))
                 (call-with-remote-output-file sftp-session witness
                                               (cut display "hello" <>))
                 (call-with-remote-input-file sftp-session witness
                                              read)))))

          (test-end)
          (exit (= (test-runner-fail-count (test-runner-current)) 0)))))

  (gexp->derivation name test))

(define %test-openssh
  (system-test
   (name "openssh")
   (description "Connect to a running OpenSSH daemon.")
   (value (run-ssh-test name
                        ;; Allow root logins with an empty password to
                        ;; simplify testing.
                        (service openssh-service-type
                                 (openssh-configuration
                                  (permit-root-login #t)
                                  (allow-empty-passwords? #t)))
                        "/var/run/sshd.pid"
                        #:sftp? #t))))

(define %test-dropbear
  (system-test
   (name "dropbear")
   (description "Connect to a running Dropbear SSH daemon.")
   (value (run-ssh-test name
                        (service dropbear-service-type
                                 (dropbear-configuration
                                  (root-login? #t)
                                  (allow-empty-passwords? #t)))
                        "/var/run/dropbear.pid"))))
