summary refs log tree commit diff
path: root/gnu/services/base.scm
blob: b8e8ccd5f1a13a63e4ffe7db8a712c18a9b26da4 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2013, 2014, 2015 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2015 Alex Kost <alezost@gmail.com>
;;; Copyright © 2015 Mark H Weaver <mhw@netris.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 services base)
  #:use-module (guix store)
  #:use-module (gnu services)
  #:use-module (gnu services dmd)
  #:use-module (gnu services networking)
  #:use-module (gnu system shadow)                ; 'user-account', etc.
  #:use-module (gnu system linux)                 ; 'pam-service', etc.
  #:use-module (gnu system file-systems)          ; 'file-system', etc.
  #:use-module (gnu packages admin)
  #:use-module ((gnu packages linux)
                #:select (eudev kbd e2fsprogs lvm2 fuse alsa-utils crda))
  #:use-module ((gnu packages base)
                #:select (canonical-package glibc))
  #:use-module (gnu packages package-management)
  #:use-module (gnu packages lsh)
  #:use-module (gnu packages lsof)
  #:use-module ((gnu build file-systems)
                #:select (mount-flags->bit-mask))
  #:use-module (guix gexp)
  #:use-module (guix records)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-26)
  #:use-module (ice-9 match)
  #:use-module (ice-9 format)
  #:export (root-file-system-service
            file-system-service
            user-unmount-service
            device-mapping-service
            swap-service
            user-processes-service
            host-name-service
            console-keymap-service
            console-font-service
            udev-service-type
            udev-service

            mingetty-configuration
            mingetty-configuration?
            mingetty-service
            mingetty-service-type

            %nscd-default-caches
            %nscd-default-configuration

            nscd-configuration
            nscd-configuration?

            nscd-cache
            nscd-cache?

            nscd-service-type
            nscd-service
            syslog-service

            guix-configuration
            guix-configuration?
            guix-service
            guix-service-type

            %base-services))

;;; Commentary:
;;;
;;; Base system services---i.e., services that 99% of the users will want to
;;; use.
;;;
;;; Code:


;;;
;;; File systems.
;;;

(define %root-file-system-dmd-service
  (dmd-service
   (documentation "Take care of the root file system.")
   (provision '(root-file-system))
   (start #~(const #t))
   (stop #~(lambda _
             ;; Return #f if successfully stopped.
             (sync)

             (call-with-blocked-asyncs
              (lambda ()
                (let ((null (%make-void-port "w")))
                  ;; Close 'dmd.log'.
                  (display "closing log\n")
                  ;; XXX: Ideally we'd use 'stop-logging', but that one
                  ;; doesn't actually close the port as of dmd 0.1.
                  (close-port (@@ (dmd comm) log-output-port))
                  (set! (@@ (dmd comm) log-output-port) null)

                  ;; Redirect the default output ports..
                  (set-current-output-port null)
                  (set-current-error-port null)

                  ;; Close /dev/console.
                  (for-each close-fdes '(0 1 2))

                  ;; At this point, there are no open files left, so the
                  ;; root file system can be re-mounted read-only.
                  (mount #f "/" #f
                         (logior MS_REMOUNT MS_RDONLY)
                         #:update-mtab? #f)

                  #f)))))
   (respawn? #f)))

(define root-file-system-service-type
  (dmd-service-type 'root-file-system
                    (const %root-file-system-dmd-service)))

(define (root-file-system-service)
  "Return a service whose sole purpose is to re-mount read-only the root file
system upon shutdown (aka. cleanly \"umounting\" root.)

This service must be the root of the service dependency graph so that its
'stop' action is invoked when dmd is the only process left."
  (service root-file-system-service-type #f))

(define (file-system->dmd-service-name file-system)
  "Return the symbol that denotes the service mounting and unmounting
FILE-SYSTEM."
  (symbol-append 'file-system-
                 (string->symbol (file-system-mount-point file-system))))

(define file-system-service-type
  ;; TODO(?): Make this an extensible service that takes <file-system> objects
  ;; and returns a list of <dmd-service>.
  (dmd-service-type
   'file-system
   (lambda (file-system)
     (let ((target  (file-system-mount-point file-system))
           (device  (file-system-device file-system))
           (type    (file-system-type file-system))
           (title   (file-system-title file-system))
           (check?  (file-system-check? file-system))
           (create? (file-system-create-mount-point? file-system))
           (dependencies (file-system-dependencies file-system)))
       (dmd-service
        (provision (list (file-system->dmd-service-name file-system)))
        (requirement `(root-file-system
                       ,@(map file-system->dmd-service-name dependencies)))
        (documentation "Check, mount, and unmount the given file system.")
        (start #~(lambda args
                   ;; FIXME: Use or factorize with 'mount-file-system'.
                   (let ((device (canonicalize-device-spec #$device '#$title))
                         (flags  #$(mount-flags->bit-mask
                                    (file-system-flags file-system))))
                     #$(if create?
                           #~(mkdir-p #$target)
                           #~#t)
                     #$(if check?
                           #~(begin
                               ;; Make sure fsck.ext2 & co. can be found.
                               (setenv "PATH"
                                       (string-append
                                        #$e2fsprogs "/sbin:"
                                        "/run/current-system/profile/sbin:"
                                        (getenv "PATH")))
                               (check-file-system device #$type))
                           #~#t)

                     (mount device #$target #$type flags
                            #$(file-system-options file-system))

                     ;; For read-only bind mounts, an extra remount is needed,
                     ;; as per <http://lwn.net/Articles/281157/>, which still
                     ;; applies to Linux 4.0.
                     (when (and (= MS_BIND (logand flags MS_BIND))
                                (= MS_RDONLY (logand flags MS_RDONLY)))
                       (mount device #$target #$type
                              (logior MS_BIND MS_REMOUNT MS_RDONLY))))
                   #t))
        (stop #~(lambda args
                  ;; Normally there are no processes left at this point, so
                  ;; TARGET can be safely unmounted.

                  ;; Make sure PID 1 doesn't keep TARGET busy.
                  (chdir "/")

                  (umount #$target)
                  #f)))))))

(define* (file-system-service file-system)
  "Return a service that mounts @var{file-system}, a @code{<file-system>}
object."
  (service file-system-service-type file-system))

(define user-unmount-service-type
  (dmd-service-type
   'user-file-systems
   (lambda (known-mount-points)
     (dmd-service
      (documentation "Unmount manually-mounted file systems.")
      (provision '(user-file-systems))
      (start #~(const #t))
      (stop #~(lambda args
                (define (known? mount-point)
                  (member mount-point
                          (cons* "/proc" "/sys" '#$known-mount-points)))

                ;; Make sure we don't keep the user's mount points busy.
                (chdir "/")

                (for-each (lambda (mount-point)
                            (format #t "unmounting '~a'...~%" mount-point)
                            (catch 'system-error
                              (lambda ()
                                (umount mount-point))
                              (lambda args
                                (let ((errno (system-error-errno args)))
                                  (format #t "failed to unmount '~a': ~a~%"
                                          mount-point (strerror errno))))))
                          (filter (negate known?) (mount-points)))
                #f))))))

(define (user-unmount-service known-mount-points)
  "Return a service whose sole purpose is to unmount file systems not listed
in KNOWN-MOUNT-POINTS when it is stopped."
  (service user-unmount-service-type known-mount-points))

(define %do-not-kill-file
  ;; Name of the file listing PIDs of processes that must survive when halting
  ;; the system.  Typical example is user-space file systems.
  "/etc/dmd/do-not-kill")

(define user-processes-service-type
  (dmd-service-type
   'user-processes
   (match-lambda
     ((requirements grace-delay)
      (dmd-service
       (documentation "When stopped, terminate all user processes.")
       (provision '(user-processes))
       (requirement (cons* 'root-file-system 'user-file-systems
                           (map file-system->dmd-service-name
                                requirements)))
       (start #~(const #t))
       (stop #~(lambda _
                 (define (kill-except omit signal)
                   ;; Kill all the processes with SIGNAL except those listed
                   ;; in OMIT and the current process.
                   (let ((omit (cons (getpid) omit)))
                     (for-each (lambda (pid)
                                 (unless (memv pid omit)
                                   (false-if-exception
                                    (kill pid signal))))
                               (processes))))

                 (define omitted-pids
                   ;; List of PIDs that must not be killed.
                   (if (file-exists? #$%do-not-kill-file)
                       (map string->number
                            (call-with-input-file #$%do-not-kill-file
                              (compose string-tokenize
                                       (@ (ice-9 rdelim) read-string))))
                       '()))

                 (define (now)
                   (car (gettimeofday)))

                 (define (sleep* n)
                   ;; Really sleep N seconds.
                   ;; Work around <http://bugs.gnu.org/19581>.
                   (define start (now))
                   (let loop ((elapsed 0))
                     (when (> n elapsed)
                       (sleep (- n elapsed))
                       (loop (- (now) start)))))

                 (define lset= (@ (srfi srfi-1) lset=))

                 (display "sending all processes the TERM signal\n")

                 (if (null? omitted-pids)
                     (begin
                       ;; Easy: terminate all of them.
                       (kill -1 SIGTERM)
                       (sleep* #$grace-delay)
                       (kill -1 SIGKILL))
                     (begin
                       ;; Kill them all except OMITTED-PIDS.  XXX: We would
                       ;; like to (kill -1 SIGSTOP) to get a fixed list of
                       ;; processes, like 'killall5' does, but that seems
                       ;; unreliable.
                       (kill-except omitted-pids SIGTERM)
                       (sleep* #$grace-delay)
                       (kill-except omitted-pids SIGKILL)
                       (delete-file #$%do-not-kill-file)))

                 (let wait ()
                   (let ((pids (processes)))
                     (unless (lset= = pids (cons 1 omitted-pids))
                       (format #t "waiting for process termination\
 (processes left: ~s)~%"
                               pids)
                       (sleep* 2)
                       (wait))))

                 (display "all processes have been terminated\n")
                 #f))
       (respawn? #f))))))

(define* (user-processes-service file-systems #:key (grace-delay 4))
  "Return the service that is responsible for terminating all the processes so
that the root file system can be re-mounted read-only, just before
rebooting/halting.  Processes still running GRACE-DELAY seconds after SIGTERM
has been sent are terminated with SIGKILL.

The returned service will depend on 'root-file-system' and on all the dmd
services corresponding to FILE-SYSTEMS.

All the services that spawn processes must depend on this one so that they are
stopped before 'kill' is called."
  (service user-processes-service-type
           (list file-systems grace-delay)))


;;;
;;; Console & co.
;;;

(define host-name-service-type
  (dmd-service-type
   'host-name
   (lambda (name)
     (dmd-service
      (documentation "Initialize the machine's host name.")
      (provision '(host-name))
      (start #~(lambda _
                 (sethostname #$name)))
      (respawn? #f)))))

(define (host-name-service name)
  "Return a service that sets the host name to @var{name}."
  (service host-name-service-type name))

(define (unicode-start tty)
  "Return a gexp to start Unicode support on @var{tty}."

  ;; We have to run 'unicode_start' in a pipe so that when it invokes the
  ;; 'tty' command, that command returns TTY.
  #~(begin
      (let ((pid (primitive-fork)))
        (case pid
          ((0)
           (close-fdes 0)
           (dup2 (open-fdes #$tty O_RDONLY) 0)
           (close-fdes 1)
           (dup2 (open-fdes #$tty O_WRONLY) 1)
           (execl (string-append #$kbd "/bin/unicode_start")
                  "unicode_start"))
          (else
           (zero? (cdr (waitpid pid))))))))

(define console-keymap-service-type
  (dmd-service-type
   'console-keymap
   (lambda (file)
     (dmd-service
      (documentation (string-append "Load console keymap (loadkeys)."))
      (provision '(console-keymap))
      (start #~(lambda _
                 (zero? (system* (string-append #$kbd "/bin/loadkeys")
                                 #$file))))
      (respawn? #f)))))

(define (console-keymap-service file)
  "Return a service to load console keymap from @var{file}."
  (service console-keymap-service-type file))

(define console-font-service-type
  (dmd-service-type
   'console-font
   (match-lambda
     ((tty font)
      (let ((device (string-append "/dev/" tty)))
        (dmd-service
         (documentation "Load a Unicode console font.")
         (provision (list (symbol-append 'console-font-
                                         (string->symbol tty))))

         ;; Start after mingetty has been started on TTY, otherwise the settings
         ;; are ignored.
         (requirement (list (symbol-append 'term-
                                           (string->symbol tty))))

         (start #~(lambda _
                    (and #$(unicode-start device)
                         (zero?
                          (system* (string-append #$kbd "/bin/setfont")
                                   "-C" #$device #$font)))))
         (stop #~(const #t))
         (respawn? #f)))))))

(define* (console-font-service tty #:optional (font "LatGrkCyr-8x16"))
  "Return a service that sets up Unicode support in @var{tty} and loads
@var{font} for that tty (fonts are per virtual console in Linux.)"
  ;; Note: 'LatGrkCyr-8x16' has the advantage of providing three common
  ;; scripts as well as glyphs for em dash, quotation marks, and other Unicode
  ;; codepoints notably found in the UTF-8 manual.
  (service console-font-service-type (list tty font)))

(define-record-type* <mingetty-configuration>
  mingetty-configuration make-mingetty-configuration
  mingetty-configuration?
  (mingetty       mingetty-configuration-mingetty ;<package>
                  (default mingetty))
  (tty            mingetty-configuration-tty)     ;string
  (motd           mingetty-configuration-motd     ;file-like
                  (default (plain-file "motd" "Welcome.\n")))
  (auto-login     mingetty-auto-login             ;string | #f
                  (default #f))
  (login-program  mingetty-login-program          ;gexp
                  (default #f))
  (login-pause?   mingetty-login-pause?           ;Boolean
                  (default #f))

  ;; Allow empty passwords by default so that first-time users can log in when
  ;; the 'root' account has just been created.
  (allow-empty-passwords? mingetty-configuration-allow-empty-passwords?
                          (default #t)))          ;Boolean

(define (mingetty-pam-service conf)
  "Return the list of PAM service needed for CONF."
  ;; Let 'login' be known to PAM.  All the mingetty services will have that
  ;; PAM service, but that's fine because they're all identical and duplicates
  ;; are removed.
  (list (unix-pam-service "login"
                          #:allow-empty-passwords?
                          (mingetty-configuration-allow-empty-passwords? conf)
                          #:motd
                          (mingetty-configuration-motd conf))))

(define mingetty-dmd-service
  (match-lambda
    (($ <mingetty-configuration> mingetty tty motd auto-login login-program
                                 login-pause? allow-empty-passwords?)
     (list
      (dmd-service
       (documentation "Run mingetty on an tty.")
       (provision (list (symbol-append 'term- (string->symbol tty))))

       ;; Since the login prompt shows the host name, wait for the 'host-name'
       ;; service to be done.  Also wait for udev essentially so that the tty
       ;; text is not lost in the middle of kernel messages (XXX).
       (requirement '(user-processes host-name udev))

       (start  #~(make-forkexec-constructor
                  (list (string-append #$mingetty "/sbin/mingetty")
                        "--noclear" #$tty
                        #$@(if auto-login
                               #~("--autologin" #$auto-login)
                               #~())
                        #$@(if login-program
                               #~("--loginprog" #$login-program)
                               #~())
                        #$@(if login-pause?
                               #~("--loginpause")
                               #~()))))
       (stop   #~(make-kill-destructor)))))))

(define mingetty-service-type
  (service-type (name 'mingetty)
                (extensions (list (service-extension dmd-root-service-type
                                                     mingetty-dmd-service)
                                  (service-extension pam-root-service-type
                                                     mingetty-pam-service)))))

(define* (mingetty-service config)
  "Return a service to run mingetty according to @var{config}, which specifies
the tty to run, among other things."
  (service mingetty-service-type config))

(define-record-type* <nscd-configuration> nscd-configuration
  make-nscd-configuration
  nscd-configuration?
  (log-file    nscd-configuration-log-file        ;string
               (default "/var/log/nscd.log"))
  (debug-level nscd-debug-level                   ;integer
               (default 0))
  ;; TODO: See nscd.conf in glibc for other options to add.
  (caches     nscd-configuration-caches           ;list of <nscd-cache>
              (default %nscd-default-caches))
  (name-services nscd-configuration-name-services ;list of <packages>
                 (default '()))
  (glibc      nscd-configuration-glibc            ;<package>
              (default (canonical-package glibc))))

(define-record-type* <nscd-cache> nscd-cache make-nscd-cache
  nscd-cache?
  (database              nscd-cache-database)              ;symbol
  (positive-time-to-live nscd-cache-positive-time-to-live) ;integer
  (negative-time-to-live nscd-cache-negative-time-to-live
                         (default 20))             ;integer
  (suggested-size        nscd-cache-suggested-size ;integer ("default module
                                                   ;of hash table")
                         (default 211))
  (check-files?          nscd-cache-check-files?  ;Boolean
                         (default #t))
  (persistent?           nscd-cache-persistent?   ;Boolean
                         (default #t))
  (shared?               nscd-cache-shared?       ;Boolean
                         (default #t))
  (max-database-size     nscd-cache-max-database-size ;integer
                         (default (* 32 (expt 2 20))))
  (auto-propagate?       nscd-cache-auto-propagate? ;Boolean
                         (default #t)))

(define %nscd-default-caches
  ;; Caches that we want to enable by default.  Note that when providing an
  ;; empty nscd.conf, all caches are disabled.
  (list (nscd-cache (database 'hosts)

                    ;; Aggressively cache the host name cache to improve
                    ;; privacy and resilience.
                    (positive-time-to-live (* 3600 12))
                    (negative-time-to-live 20)
                    (persistent? #t))

        (nscd-cache (database 'services)

                    ;; Services are unlikely to change, so we can be even more
                    ;; aggressive.
                    (positive-time-to-live (* 3600 24))
                    (negative-time-to-live 3600)
                    (check-files? #t)             ;check /etc/services changes
                    (persistent? #t))))

(define %nscd-default-configuration
  ;; Default nscd configuration.
  (nscd-configuration))

(define (nscd.conf-file config)
  "Return the @file{nscd.conf} configuration file for @var{config}, an
@code{<nscd-configuration>} object."
  (define cache->config
    (match-lambda
      (($ <nscd-cache> (= symbol->string database)
                       positive-ttl negative-ttl size check-files?
                       persistent? shared? max-size propagate?)
       (string-append "\nenable-cache\t" database "\tyes\n"

                      "positive-time-to-live\t" database "\t"
                      (number->string positive-ttl) "\n"
                      "negative-time-to-live\t" database "\t"
                      (number->string negative-ttl) "\n"
                      "suggested-size\t" database "\t"
                      (number->string size) "\n"
                      "check-files\t" database "\t"
                      (if check-files? "yes\n" "no\n")
                      "persistent\t" database "\t"
                      (if persistent? "yes\n" "no\n")
                      "shared\t" database "\t"
                      (if shared? "yes\n" "no\n")
                      "max-db-size\t" database "\t"
                      (number->string max-size) "\n"
                      "auto-propagate\t" database "\t"
                      (if propagate? "yes\n" "no\n")))))

  (match config
    (($ <nscd-configuration> log-file debug-level caches)
     (plain-file "nscd.conf"
                 (string-append "\
# Configuration of libc's name service cache daemon (nscd).\n\n"
                                (if log-file
                                    (string-append "logfile\t" log-file)
                                    "")
                                "\n"
                                (if debug-level
                                    (string-append "debug-level\t"
                                                   (number->string debug-level))
                                    "")
                                "\n"
                                (string-concatenate
                                 (map cache->config caches)))))))

(define (nscd-dmd-service config)
  "Return a dmd service for CONFIG, an <nscd-configuration> object."
  (let ((nscd.conf     (nscd.conf-file config))
        (name-services (nscd-configuration-name-services config)))
    (list (dmd-service
           (documentation "Run libc's name service cache daemon (nscd).")
           (provision '(nscd))
           (requirement '(user-processes))
           (start #~(make-forkexec-constructor
                     (list (string-append #$(nscd-configuration-glibc config)
                                          "/sbin/nscd")
                           "-f" #$nscd.conf "--foreground")

                     #:environment-variables
                     (list (string-append "LD_LIBRARY_PATH="
                                          (string-join
                                           (map (lambda (dir)
                                                  (string-append dir "/lib"))
                                                (list #$@name-services))
                                           ":")))))
           (stop #~(make-kill-destructor))

           (respawn? #f)))))

(define nscd-activation
  ;; Actions to take before starting nscd.
  #~(begin
      (use-modules (guix build utils))
      (mkdir-p "/var/run/nscd")
      (mkdir-p "/var/db/nscd")))                  ;for the persistent cache

(define nscd-service-type
  (service-type (name 'nscd)
                (extensions
                 (list (service-extension activation-service-type
                                          (const nscd-activation))
                       (service-extension dmd-root-service-type
                                          nscd-dmd-service)))

                ;; This can be extended by providing additional name services
                ;; such as nss-mdns.
                (compose concatenate)
                (extend (lambda (config name-services)
                          (nscd-configuration
                           (inherit config)
                           (name-services (append
                                           (nscd-configuration-name-services config)
                                           name-services)))))))

(define* (nscd-service #:optional (config %nscd-default-configuration))
  "Return a service that runs libc's name service cache daemon (nscd) with the
given @var{config}---an @code{<nscd-configuration>} object.  @xref{Name
Service Switch}, for an example."
  (service nscd-service-type config))

(define syslog-service-type
  (dmd-service-type
   'syslog
   (lambda (config-file)
     (dmd-service
      (documentation "Run the syslog daemon (syslogd).")
      (provision '(syslogd))
      (requirement '(user-processes))
      (start #~(make-forkexec-constructor
                (list (string-append #$inetutils "/libexec/syslogd")
                      "--no-detach" "--rcfile" #$config-file)))
      (stop #~(make-kill-destructor))))))

;; Snippet adapted from the GNU inetutils manual.
(define %default-syslog.conf
  (plain-file "syslog.conf" "
     # Log all error messages, authentication messages of
     # level notice or higher and anything of level err or
     # higher to the console.
     # Don't log private authentication messages!
     *.alert;auth.notice;authpriv.none       /dev/console

     # Log anything (except mail) of level info or higher.
     # Don't log private authentication messages!
     *.info;mail.none;authpriv.none          /var/log/messages

     # Same, in a different place.
     *.info;mail.none;authpriv.none          /dev/tty12

     # The authpriv file has restricted access.
     authpriv.*                              /var/log/secure

     # Log all the mail messages in one place.
     mail.*                                  /var/log/maillog
"))

(define* (syslog-service #:key (config-file %default-syslog.conf))
  "Return a service that runs @code{syslogd}.
If configuration file name @var{config-file} is not specified, use some
reasonable default settings."
  (service syslog-service-type config-file))

(define* (guix-build-accounts count #:key
                              (group "guixbuild")
                              (first-uid 30001)
                              (shadow shadow))
  "Return a list of COUNT user accounts for Guix build users, with UIDs
starting at FIRST-UID, and under GID."
  (unfold (cut > <> count)
          (lambda (n)
            (user-account
             (name (format #f "guixbuilder~2,'0d" n))
             (system? #t)
             (uid (+ first-uid n -1))
             (group group)

             ;; guix-daemon expects GROUP to be listed as a
             ;; supplementary group too:
             ;; <http://lists.gnu.org/archive/html/bug-guix/2013-01/msg00239.html>.
             (supplementary-groups (list group "kvm"))

             (comment (format #f "Guix Build User ~2d" n))
             (home-directory "/var/empty")
             (shell #~(string-append #$shadow "/sbin/nologin"))))
          1+
          1))

(define (hydra-key-authorization guix)
  "Return a gexp with code to register the hydra.gnu.org public key with
GUIX."
  #~(unless (file-exists? "/etc/guix/acl")
      (let ((pid (primitive-fork)))
        (case pid
          ((0)
           (let* ((key  (string-append #$guix
                                       "/share/guix/hydra.gnu.org.pub"))
                  (port (open-file key "r0b")))
             (format #t "registering public key '~a'...~%" key)
             (close-port (current-input-port))
             (dup port 0)
             (execl (string-append #$guix "/bin/guix")
                    "guix" "archive" "--authorize")
             (exit 1)))
          (else
           (let ((status (cdr (waitpid pid))))
             (unless (zero? status)
               (format (current-error-port) "warning: \
failed to register hydra.gnu.org public key: ~a~%" status))))))))

(define-record-type* <guix-configuration>
  guix-configuration make-guix-configuration
  guix-configuration?
  (guix             guix-configuration-guix       ;<package>
                    (default guix))
  (build-group      guix-configuration-build-group ;string
                    (default "guixbuild"))
  (build-accounts   guix-configuration-build-accounts ;integer
                    (default 10))
  (authorize-key?   guix-configuration-authorize-key? ;Boolean
                    (default #t))
  (use-substitutes? guix-configuration-use-substitutes? ;Boolean
                    (default #t))
  (substitute-urls  guix-configuration-substitute-urls ;list of strings
                    (default %default-substitute-urls))
  (extra-options    guix-configuration-extra-options ;list of strings
                    (default '()))
  (lsof             guix-configuration-lsof       ;<package>
                    (default lsof))
  (lsh              guix-configuration-lsh        ;<package>
                    (default lsh)))

(define %default-guix-configuration
  (guix-configuration))

(define (guix-dmd-service config)
  "Return a <dmd-service> for the Guix daemon service with CONFIG."
  (match config
    (($ <guix-configuration> guix build-group build-accounts authorize-key?
                             use-substitutes? substitute-urls extra-options
                             lsof lsh)
     (list (dmd-service
            (documentation "Run the Guix daemon.")
            (provision '(guix-daemon))
            (requirement '(user-processes))
            (start
             #~(make-forkexec-constructor
                (list (string-append #$guix "/bin/guix-daemon")
                      "--build-users-group" #$build-group
                      #$@(if use-substitutes?
                             '()
                             '("--no-substitutes"))
                      "--substitute-urls" #$(string-join substitute-urls)
                      #$@extra-options)

                ;; Add 'lsof' (for the GC) and 'lsh' (for offloading) to the
                ;; daemon's $PATH.
                #:environment-variables
                (list (string-append "PATH=" #$lsof "/bin:" #$lsh "/bin"))))
            (stop #~(make-kill-destructor)))))))

(define (guix-accounts config)
  "Return the user accounts and user groups for CONFIG."
  (match config
    (($ <guix-configuration> _ build-group build-accounts)
     (cons (user-group
            (name build-group)
            (system? #t)

            ;; Use a fixed GID so that we can create the store with the right
            ;; owner.
            (id 30000))
           (guix-build-accounts build-accounts
                                #:group build-group)))))

(define (guix-activation config)
  "Return the activation gexp for CONFIG."
  (match config
    (($ <guix-configuration> guix build-group build-accounts authorize-key?)
     ;; Assume that the store has BUILD-GROUP as its group.  We could
     ;; otherwise call 'chown' here, but the problem is that on a COW unionfs,
     ;; chown leads to an entire copy of the tree, which is a bad idea.

     ;; Optionally authorize hydra.gnu.org's key.
     (and authorize-key?
          (hydra-key-authorization guix)))))

(define guix-service-type
  (service-type
   (name 'guix)
   (extensions
    (list (service-extension dmd-root-service-type guix-dmd-service)
          (service-extension account-service-type guix-accounts)
          (service-extension activation-service-type guix-activation)))))

(define* (guix-service #:optional (config %default-guix-configuration))
  "Return a service that runs the Guix build daemon according to
@var{config}."
  (service guix-service-type config))


;;;
;;; Udev.
;;;

(define-record-type* <udev-configuration>
  udev-configuration make-udev-configuration
  udev-configuration?
  (udev   udev-configuration-udev                 ;<package>
          (default udev))
  (rules  udev-configuration-rules                ;list of <package>
          (default '())))

(define (udev-rules-union packages)
  "Return the union of the @code{lib/udev/rules.d} directories found in each
item of @var{packages}."
  (define build
    #~(begin
        (use-modules (guix build union)
                     (guix build utils)
                     (srfi srfi-1)
                     (srfi srfi-26))

        (define %standard-locations
          '("/lib/udev/rules.d" "/libexec/udev/rules.d"))

        (define (rules-sub-directory directory)
          ;; Return the sub-directory of DIRECTORY containing udev rules, or
          ;; #f if none was found.
          (find directory-exists?
                (map (cut string-append directory <>) %standard-locations)))

        (mkdir-p (string-append #$output "/lib/udev"))
        (union-build (string-append #$output "/lib/udev/rules.d")
                     (filter-map rules-sub-directory '#$packages))))

  (computed-file "udev-rules" build
                 #:modules '((guix build union)
                             (guix build utils))))

(define* (kvm-udev-rule)
  "Return a directory with a udev rule that changes the group of
@file{/dev/kvm} to \"kvm\" and makes it #o660."
  ;; Apparently QEMU-KVM used to ship this rule, but now we have to add it by
  ;; ourselves.
  (computed-file "kvm-udev-rules"
                 #~(begin
                     (use-modules (guix build utils))

                     (define rules.d
                       (string-append #$output "/lib/udev/rules.d"))

                     (mkdir-p rules.d)
                     (call-with-output-file
                         (string-append rules.d "/90-kvm.rules")
                       (lambda (port)
                         ;; Build users are part of the "kvm" group, so we
                         ;; can fearlessly make /dev/kvm 660 (see
                         ;; <http://bugs.gnu.org/18994>, for background.)
                         (display "\
KERNEL==\"kvm\", GROUP=\"kvm\", MODE=\"0660\"\n" port))))
                 #:modules '((guix build utils))))

(define udev-dmd-service
  ;; Return a <dmd-service> for UDEV with RULES.
  (match-lambda
    (($ <udev-configuration> udev rules)
     (let* ((rules     (udev-rules-union (cons* udev (kvm-udev-rule) rules)))
            (udev.conf (computed-file "udev.conf"
                                      #~(call-with-output-file #$output
                                          (lambda (port)
                                            (format port
                                                    "udev_rules=\"~a/lib/udev/rules.d\"\n"
                                                    #$rules))))))
       (list
        (dmd-service
         (provision '(udev))

         ;; Udev needs /dev to be a 'devtmpfs' mount so that new device nodes can
         ;; be added: see
         ;; <http://www.linuxfromscratch.org/lfs/view/development/chapter07/udev.html>.
         (requirement '(root-file-system))

         (documentation "Populate the /dev directory, dynamically.")
         (start #~(lambda ()
                    (define find
                      (@ (srfi srfi-1) find))

                    (define udevd
                      ;; Choose the right 'udevd'.
                      (find file-exists?
                            (map (lambda (suffix)
                                   (string-append #$udev suffix))
                                 '("/libexec/udev/udevd" ;udev
                                   "/sbin/udevd"))))     ;eudev

                    (define (wait-for-udevd)
                      ;; Wait until someone's listening on udevd's control
                      ;; socket.
                      (let ((sock (socket AF_UNIX SOCK_SEQPACKET 0)))
                        (let try ()
                          (catch 'system-error
                            (lambda ()
                              (connect sock PF_UNIX "/run/udev/control")
                              (close-port sock))
                            (lambda args
                              (format #t "waiting for udevd...~%")
                              (usleep 500000)
                              (try))))))

                    ;; Allow udev to find the modules.
                    (setenv "LINUX_MODULE_DIRECTORY"
                            "/run/booted-system/kernel/lib/modules")

                    ;; The first one is for udev, the second one for eudev.
                    (setenv "UDEV_CONFIG_FILE" #$udev.conf)
                    (setenv "EUDEV_RULES_DIRECTORY"
                            (string-append #$rules "/lib/udev/rules.d"))

                    (let ((pid (primitive-fork)))
                      (case pid
                        ((0)
                         (exec-command (list udevd)))
                        (else
                         ;; Wait until udevd is up and running.  This
                         ;; appears to be needed so that the events
                         ;; triggered below are actually handled.
                         (wait-for-udevd)

                         ;; Trigger device node creation.
                         (system* (string-append #$udev "/bin/udevadm")
                                  "trigger" "--action=add")

                         ;; Wait for things to settle down.
                         (system* (string-append #$udev "/bin/udevadm")
                                  "settle")
                         pid)))))
         (stop #~(make-kill-destructor))

         ;; When halting the system, 'udev' is actually killed by
         ;; 'user-processes', i.e., before its own 'stop' method was called.
         ;; Thus, make sure it is not respawned.
         (respawn? #f)))))))

(define udev-service-type
  (service-type (name 'udev)
                (extensions
                 (list (service-extension dmd-root-service-type
                                          udev-dmd-service)))

                (compose concatenate)           ;concatenate the list of rules
                (extend (lambda (config rules)
                          (match config
                            (($ <udev-configuration> udev initial-rules)
                             (udev-configuration
                              (udev udev)
                              (rules (append initial-rules rules)))))))))

(define* (udev-service #:key (udev eudev) (rules '()))
  "Run @var{udev}, which populates the @file{/dev} directory dynamically.  Get
extra rules from the packages listed in @var{rules}."
  (service udev-service-type
           (udev-configuration (udev udev) (rules rules))))

(define device-mapping-service-type
  (dmd-service-type
   'device-mapping
   (match-lambda
     ((target open close)
      (dmd-service
       (provision (list (symbol-append 'device-mapping- (string->symbol target))))
       (requirement '(udev))
       (documentation "Map a device node using Linux's device mapper.")
       (start #~(lambda () #$open))
       (stop #~(lambda _ (not #$close)))
       (respawn? #f))))))

(define (device-mapping-service target open close)
  "Return a service that maps device @var{target}, a string such as
@code{\"home\"} (meaning @code{/dev/mapper/home}).  Evaluate @var{open}, a
gexp, to open it, and evaluate @var{close} to close it."
  (service device-mapping-service-type
           (list target open close)))

(define swap-service-type
  (dmd-service-type
   'swap
   (lambda (device)
     (define requirement
       (if (string-prefix? "/dev/mapper/" device)
           (list (symbol-append 'device-mapping-
                                (string->symbol (basename device))))
           '()))

     (dmd-service
      (provision (list (symbol-append 'swap- (string->symbol device))))
      (requirement `(udev ,@requirement))
      (documentation "Enable the given swap device.")
      (start #~(lambda ()
                 (restart-on-EINTR (swapon #$device))
                 #t))
      (stop #~(lambda _
                (restart-on-EINTR (swapoff #$device))
                #f))
      (respawn? #f)))))

(define (swap-service device)
  "Return a service that uses @var{device} as a swap device."
  (service swap-service-type device))

(define %base-services
  ;; Convenience variable holding the basic services.
  (let ((motd (plain-file "motd" "
This is the GNU operating system, welcome!\n\n")))
    (list (console-font-service "tty1")
          (console-font-service "tty2")
          (console-font-service "tty3")
          (console-font-service "tty4")
          (console-font-service "tty5")
          (console-font-service "tty6")

          (mingetty-service (mingetty-configuration
                             (tty "tty1") (motd motd)))
          (mingetty-service (mingetty-configuration
                             (tty "tty2") (motd motd)))
          (mingetty-service (mingetty-configuration
                             (tty "tty3") (motd motd)))
          (mingetty-service (mingetty-configuration
                             (tty "tty4") (motd motd)))
          (mingetty-service (mingetty-configuration
                             (tty "tty5") (motd motd)))
          (mingetty-service (mingetty-configuration
                             (tty "tty6") (motd motd)))

          (static-networking-service "lo" "127.0.0.1"
                                     #:provision '(loopback))
          (syslog-service)
          (guix-service)
          (nscd-service)

          ;; The LVM2 rules are needed as soon as LVM2 or the device-mapper is
          ;; used, so enable them by default.  The FUSE and ALSA rules are
          ;; less critical, but handy.
          (udev-service #:rules (list lvm2 fuse alsa-utils crda)))))

;;; base.scm ends here