summary refs log tree commit diff
path: root/gnu/services/virtualization.scm
blob: d87e494348c0883201b7b16cc3b48e3a8642349a (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
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2017 Ryan Moe <ryan.moe@gmail.com>
;;; Copyright © 2018, 2020-2024 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2020, 2021, 2023 Janneke Nieuwenhuizen <janneke@gnu.org>
;;; Copyright © 2021 Timotej Lazar <timotej.lazar@araneo.si>
;;; Copyright © 2022 Oleg Pykhalov <go.wigust@gmail.com>
;;; Copyright © 2022 Leo Nikkilä <hello@lnikki.la>
;;; Copyright © 2023 Efraim Flashner <efraim@flashner.co.il>
;;;
;;; 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 virtualization)
  #:use-module (gnu bootloader)
  #:use-module (gnu bootloader grub)
  #:use-module (gnu image)
  #:use-module (gnu packages admin)
  #:use-module (gnu packages bash)
  #:use-module (gnu packages gdb)
  #:autoload   (gnu packages gnupg) (guile-gcrypt)
  #:use-module (gnu packages package-management)
  #:use-module (gnu packages ssh)
  #:use-module (gnu packages virtualization)
  #:use-module (gnu services base)
  #:use-module (gnu services configuration)
  #:use-module (gnu services dbus)
  #:use-module (gnu services mcron)
  #:use-module (gnu services shepherd)
  #:use-module (gnu services ssh)
  #:use-module (gnu services)
  #:use-module (gnu system file-systems)
  #:use-module (gnu system hurd)
  #:use-module (gnu system image)
  #:use-module (gnu system shadow)
  #:autoload   (gnu system vm) (linux-image-startup-command
                                virtualized-operating-system)
  #:autoload   (gnu system locale) (locale-definition)
  #:use-module (gnu system)
  #:use-module (guix derivations)
  #:use-module (guix gexp)
  #:use-module (guix modules)
  #:use-module (guix monads)
  #:use-module (guix packages)
  #:use-module (guix records)
  #:use-module (guix store)
  #:use-module (guix utils)
  #:autoload   (guix self) (make-config.scm)
  #:autoload   (guix platform) (platform-system)

  #:use-module ((srfi srfi-1) #:hide (partition))
  #:use-module (srfi srfi-9)
  #:use-module (srfi srfi-19)
  #:use-module (srfi srfi-26)
  #:use-module (rnrs bytevectors)
  #:use-module (ice-9 match)

  #:export (virtual-build-machine
            virtual-build-machine-service-type

            %virtual-build-machine-operating-system
            %virtual-build-machine-default-vm

            %hurd-vm-operating-system
            hurd-vm-configuration
            hurd-vm-configuration?
            hurd-vm-configuration-os
            hurd-vm-configuration-qemu
            hurd-vm-configuration-image
            hurd-vm-configuration-disk-size
            hurd-vm-configuration-memory-size
            hurd-vm-configuration-options
            hurd-vm-configuration-id
            hurd-vm-configuration-net-options
            hurd-vm-configuration-secrets

            hurd-vm-disk-image
            hurd-vm-port
            hurd-vm-net-options
            hurd-vm-service-type

            libvirt-configuration
            libvirt-service-type
            virtlog-configuration
            virtlog-service-type

            %qemu-platforms
            lookup-qemu-platforms
            qemu-platform?
            qemu-platform-name

            qemu-binfmt-configuration
            qemu-binfmt-configuration?
            qemu-binfmt-service-type

            qemu-guest-agent-configuration
            qemu-guest-agent-configuration?
            qemu-guest-agent-service-type))

(define (uglify-field-name field-name)
  (let ((str (symbol->string field-name)))
    (string-join
     (string-split (string-delete #\? str) #\-)
     "_")))

(define (quote-val val)
  (string-append "\"" val "\""))

(define (serialize-field field-name val)
  (format #t "~a = ~a\n" (uglify-field-name field-name) val))

(define (serialize-string field-name val)
  (serialize-field field-name (quote-val val)))

(define (serialize-boolean field-name val)
  (serialize-field field-name (if val 1 0)))

(define (serialize-integer field-name val)
  (serialize-field field-name val))

(define (build-opt-list val)
  (string-append
   "["
   (string-join (map quote-val val) ",")
   "]"))

(define optional-list? list?)
(define optional-string? string?)

(define (serialize-list field-name val)
  (serialize-field field-name (build-opt-list val)))

(define (serialize-optional-list field-name val)
  (if (null? val)
      (format #t "# ~a = []\n" (uglify-field-name field-name))
      (serialize-list field-name val)))

(define (serialize-optional-string field-name val)
  (if (string-null? val)
      (format #t "# ~a = \"\"\n" (uglify-field-name field-name))
      (serialize-string field-name val)))

(define-configuration libvirt-configuration
  (libvirt
   (file-like libvirt)
   "Libvirt package.")
  (qemu
   (file-like qemu)
   "Qemu package.")

  (listen-tls?
   (boolean #t)
   "Flag listening for secure TLS connections on the public TCP/IP port.
must set @code{listen} for this to have any effect.

It is necessary to setup a CA and issue server certificates before
using this capability.")
  (listen-tcp?
   (boolean #f)
   "Listen for unencrypted TCP connections on the public TCP/IP port.
must set @code{listen} for this to have any effect.

Using the TCP socket requires SASL authentication by default. Only
SASL mechanisms which support data encryption are allowed. This is
DIGEST_MD5 and GSSAPI (Kerberos5)")
  (tls-port
   (string "16514")
   "Port for accepting secure TLS connections This can be a port number,
or service name")
  (tcp-port
   (string "16509")
   "Port for accepting insecure TCP connections This can be a port number,
or service name")
  (listen-addr
   (string "0.0.0.0")
   "IP address or hostname used for client connections.")
  (mdns-adv?
   (boolean #f)
   "Flag toggling mDNS advertisement of the libvirt service.

Alternatively can disable for all services on a host by
stopping the Avahi daemon.")
  (mdns-name
   (string (string-append "Virtualization Host " (gethostname)))
   "Default mDNS advertisement name. This must be unique on the
immediate broadcast network.")
  (unix-sock-group
   (string "libvirt")
   "UNIX domain socket group ownership. This can be used to
allow a 'trusted' set of users access to management capabilities
without becoming root.")
  (unix-sock-ro-perms
   (string "0777")
   "UNIX socket permissions for the R/O socket. This is used
for monitoring VM status only.")
  (unix-sock-rw-perms
   (string "0770")
   "UNIX socket permissions for the R/W socket. Default allows
only root. If PolicyKit is enabled on the socket, the default
will change to allow everyone (eg, 0777)")
  (unix-sock-admin-perms
   (string "0777")
   "UNIX socket permissions for the admin socket. Default allows
only owner (root), do not change it unless you are sure to whom
you are exposing the access to.")
  (unix-sock-dir
   (string "/var/run/libvirt")
   "The directory in which sockets will be found/created.")
  (auth-unix-ro
   (string "polkit")
   "Authentication scheme for UNIX read-only sockets. By default
socket permissions allow anyone to connect")
  (auth-unix-rw
   (string "polkit")
   "Authentication scheme for UNIX read-write sockets. By default
socket permissions only allow root. If PolicyKit support was compiled
into libvirt, the default will be to use 'polkit' auth.")
  (auth-tcp
   (string "sasl")
   "Authentication scheme for TCP sockets. If you don't enable SASL,
then all TCP traffic is cleartext. Don't do this outside of a dev/test
scenario.")
  (auth-tls
   (string "none")
   "Authentication scheme for TLS sockets. TLS sockets already have
encryption provided by the TLS layer, and limited authentication is
done by certificates.

It is possible to make use of any SASL authentication mechanism as
well, by using 'sasl' for this option")
  (access-drivers
   (optional-list '())
   "API access control scheme.

By default an authenticated user is allowed access to all APIs. Access
drivers can place restrictions on this.")
  (key-file
   (string "")
   "Server key file path. If set to an empty string, then no private key
is loaded.")
  (cert-file
   (string "")
   "Server key file path. If set to an empty string, then no certificate
is loaded.")
  (ca-file
   (string "")
   "Server key file path. If set to an empty string, then no CA certificate
is loaded.")
  (crl-file
   (string "")
   "Certificate revocation list path. If set to an empty string, then no
CRL is loaded.")
  (tls-no-sanity-cert
   (boolean #f)
   "Disable verification of our own server certificates.

When libvirtd starts it performs some sanity checks against its own
certificates.")
  (tls-no-verify-cert
   (boolean #f)
   "Disable verification of client certificates.

Client certificate verification is the primary authentication mechanism.
Any client which does not present a certificate signed by the CA
will be rejected.")
  (tls-allowed-dn-list
   (optional-list '())
   "Whitelist of allowed x509 Distinguished Name.")
  (sasl-allowed-usernames
   (optional-list '())
   "Whitelist of allowed SASL usernames. The format for username
depends on the SASL authentication mechanism.")
  (tls-priority
   (string "NORMAL")
   "Override the compile time default TLS priority string. The
default is usually \"NORMAL\" unless overridden at build time.
Only set this is it is desired for libvirt to deviate from
the global default settings.")
  (max-clients
   (integer 5000)
   "Maximum number of concurrent client connections to allow
over all sockets combined.")
  (max-queued-clients
   (integer 1000)
   "Maximum length of queue of connections waiting to be
accepted by the daemon. Note, that some protocols supporting
retransmission may obey this so that a later reattempt at
connection succeeds.")
  (max-anonymous-clients
   (integer 20)
   "Maximum length of queue of accepted but not yet authenticated
clients. Set this to zero to turn this feature off")
  (min-workers
   (integer 5)
   "Number of workers to start up initially.")
  (max-workers
   (integer 20)
   "Maximum number of worker threads.

If the number of active clients exceeds @code{min-workers},
then more threads are spawned, up to max_workers limit.
Typically you'd want max_workers to equal maximum number
of clients allowed.")
  (prio-workers
   (integer 5)
   "Number of priority workers. If all workers from above
pool are stuck, some calls marked as high priority
(notably domainDestroy) can be executed in this pool.")
  (max-requests
    (integer 20)
    "Total global limit on concurrent RPC calls.")
  (max-client-requests
    (integer 5)
    "Limit on concurrent requests from a single client
connection. To avoid one client monopolizing the server
this should be a small fraction of the global max_requests
and max_workers parameter.")
  (admin-min-workers
    (integer 1)
    "Same as @code{min-workers} but for the admin interface.")
  (admin-max-workers
     (integer 5)
    "Same as @code{max-workers} but for the admin interface.")
  (admin-max-clients
    (integer 5)
    "Same as @code{max-clients} but for the admin interface.")
  (admin-max-queued-clients
    (integer 5)
    "Same as @code{max-queued-clients} but for the admin interface.")
  (admin-max-client-requests
    (integer 5)
    "Same as @code{max-client-requests} but for the admin interface.")
  (log-level
    (integer 3)
    "Logging level. 4 errors, 3 warnings, 2 information, 1 debug.")
  (log-filters
    (string "3:remote 4:event")
    "Logging filters.

A filter allows selecting a different logging level for a given category
of logs
The format for a filter is one of:
@itemize
@item x:name

@item x:+name
@end itemize

where @code{name} is a string which is matched against the category
given in the @code{VIR_LOG_INIT()} at the top of each libvirt source
file, e.g., \"remote\", \"qemu\", or \"util.json\" (the name in the
filter can be a substring of the full category name, in order
to match multiple similar categories), the optional \"+\" prefix
tells libvirt to log stack trace for each message matching
name, and @code{x} is the minimal level where matching messages should
be logged:

@itemize
@item 1: DEBUG
@item 2: INFO
@item 3: WARNING
@item 4: ERROR
@end itemize

Multiple filters can be defined in a single filters statement, they just
need to be separated by spaces.")
  (log-outputs
    (string "3:syslog:libvirtd")
    "Logging outputs.

An output is one of the places to save logging information
The format for an output can be:

@table @code
@item x:stderr
output goes to stderr

@item x:syslog:name
use syslog for the output and use the given name as the ident

@item x:file:file_path
output to a file, with the given filepath

@item x:journald
output to journald logging system
@end table

In all case the x prefix is the minimal level, acting as a filter

@itemize
@item 1: DEBUG
@item 2: INFO
@item 3: WARNING
@item 4: ERROR
@end itemize

Multiple outputs can be defined, they just need to be separated by spaces.")
  (audit-level
    (integer 1)
    "Allows usage of the auditing subsystem to be altered

@itemize
@item 0: disable all auditing
@item 1: enable auditing, only if enabled on host
@item 2: enable auditing, and exit if disabled on host.
@end itemize
")
  (audit-logging
    (boolean #f)
    "Send audit messages via libvirt logging infrastructure.")
  (host-uuid
    (optional-string "")
    "Host UUID. UUID must not have all digits be the same.")
  (host-uuid-source
    (string "smbios")
    "Source to read host UUID.

@itemize

@item @code{smbios}: fetch the UUID from @code{dmidecode -s system-uuid}

@item @code{machine-id}: fetch the UUID from @code{/etc/machine-id}

@end itemize

If @code{dmidecode} does not provide a valid UUID a temporary UUID
will be generated.")
  (keepalive-interval
    (integer 5)
    "A keepalive message is sent to a client after
@code{keepalive_interval} seconds of inactivity to check if
the client is still responding. If set to -1, libvirtd will
never send keepalive requests; however clients can still send
them and the daemon will send responses.")
  (keepalive-count
    (integer 5)
    "Maximum number of keepalive messages that are allowed to be sent
to the client without getting any response before the connection is
considered broken.

In other words, the connection is automatically
closed approximately after
@code{keepalive_interval * (keepalive_count + 1)} seconds since the last
message received from the client. When @code{keepalive-count} is
set to 0, connections will be automatically closed after
@code{keepalive-interval} seconds of inactivity without sending any
keepalive messages.")
  (admin-keepalive-interval
    (integer 5)
    "Same as above but for admin interface.")
  (admin-keepalive-count
    (integer 5)
    "Same as above but for admin interface.")
  (ovs-timeout
    (integer 5)
    "Timeout for Open vSwitch calls.

The @code{ovs-vsctl} utility is used for the configuration and
its timeout option is set by default to 5 seconds to avoid
potential infinite waits blocking libvirt."))

(define* (libvirt-conf-file config)
  "Return a libvirtd config file."
  (plain-file "libvirtd.conf"
              (with-output-to-string
                (lambda ()
                  (serialize-configuration config libvirt-configuration-fields)))))

(define %libvirt-accounts
  (list (user-group (name "libvirt") (system? #t))))

(define (%libvirt-activation config)
  (let ((sock-dir (libvirt-configuration-unix-sock-dir config)))
    #~(begin
        (use-modules (guix build utils))
        (mkdir-p #$sock-dir))))


(define (libvirt-shepherd-service config)
  (let* ((config-file (libvirt-conf-file config))
         (libvirt (libvirt-configuration-libvirt config))
         (listen-tcp? (libvirt-configuration-listen-tcp? config)))
    (list (shepherd-service
           (documentation "Run the libvirt daemon.")
           (provision '(libvirtd))
           (requirement '(dbus-system))
           (start #~(make-forkexec-constructor
                     (list (string-append #$libvirt "/sbin/libvirtd")
                           "-f" #$config-file
                           #$@(if listen-tcp? '("--listen") '()))
                     ;; For finding qemu and ip binaries.
                     #:environment-variables
                     (list (string-append
                            "PATH=/run/current-system/profile/bin:"
                            "/run/current-system/profile/sbin"))))
           (stop #~(make-kill-destructor))))))

(define libvirt-service-type
  (service-type (name 'libvirt)
		(extensions
                 (list
                  (service-extension polkit-service-type
                                     (compose list libvirt-configuration-libvirt))
                  (service-extension profile-service-type
                                     (lambda (config)
                                       (list
                                        (libvirt-configuration-libvirt config)
                                        (libvirt-configuration-qemu config))))
                  (service-extension activation-service-type
                                     %libvirt-activation)
                  (service-extension shepherd-root-service-type
                                     libvirt-shepherd-service)
                  (service-extension account-service-type
                                     (const %libvirt-accounts))))
                (default-value (libvirt-configuration))
                (description "Run @command{libvirtd}, a daemon of the libvirt
virtualization management system.  This daemon runs on host servers and
performs required management tasks for virtualized guests.")))


(define-record-type* <virtlog-configuration>
  virtlog-configuration make-virtlog-configuration
  virtlog-configuration?
  (libvirt      virtlog-configuration-libvirt
                (default libvirt))
  (log-level    virtlog-configuration-log-level
                (default 3))
  (log-filters  virtlog-configuration-log-filters
                (default "3:remote 4:event"))
  (log-outputs  virtlog-configuration-log-outputs
                (default "3:syslog:virtlogd"))
  (max-clients  virtlog-configuration-max-clients
                (default 1024))
  (max-size     virtlog-configuration-max-size
                (default 2097152)) ;; 2MB
  (max-backups  virtlog-configuration-max-backups
                (default 3)))

(define* (virtlogd-conf-file config)
  "Return a virtlogd config file."
  (plain-file "virtlogd.conf"
              (string-append
               "log_level = " (number->string (virtlog-configuration-log-level config)) "\n"
               "log_filters = \"" (virtlog-configuration-log-filters config) "\"\n"
               "log_outputs = \"" (virtlog-configuration-log-outputs config) "\"\n"
               "max_clients = " (number->string (virtlog-configuration-max-clients config)) "\n"
               "max_size = " (number->string (virtlog-configuration-max-size config)) "\n"
               "max_backups = " (number->string (virtlog-configuration-max-backups config)) "\n")))

(define (virtlogd-shepherd-service config)
  (let* ((config-file (virtlogd-conf-file config))
         (libvirt (virtlog-configuration-libvirt config)))
    (list (shepherd-service
           (documentation "Run the virtlog daemon.")
           (provision '(virtlogd))
           (start #~(make-forkexec-constructor
                     (list (string-append #$libvirt "/sbin/virtlogd")
                           "-f" #$config-file)))
           (stop #~(make-kill-destructor))))))

(define virtlog-service-type
  (service-type (name 'virtlogd)
		(extensions
                 (list
                  (service-extension shepherd-root-service-type
                                     virtlogd-shepherd-service)))
                (default-value (virtlog-configuration))
                (description "Run @command{virtlogd}, a daemon libvirt that is
used to manage logs from @acronym{VM, virtual machine} consoles.")))

(define (generate-libvirt-documentation)
  (generate-documentation
   `((libvirt-configuration ,libvirt-configuration-fields))
   'libvirt-configuration))


;;;
;;; Transparent QEMU emulation via binfmt_misc.
;;;

;; Platforms that QEMU can emulate.
(define-record-type* <qemu-platform>
  qemu-platform make-qemu-platform
  qemu-platform?
  (name     qemu-platform-name)                   ;string
  (family   qemu-platform-family)                 ;string
  (magic    qemu-platform-magic)                  ;bytevector
  (mask     qemu-platform-mask)                   ;bytevector

  ;; Default flags:
  ;;
  ;;   "F": fix binary.  Open the qemu-user binary (statically linked) as soon
  ;;   as binfmt_misc interpretation is handled.
  ;;
  ;;   "P": preserve argv[0].  QEMU 6.0 detects whether it's started with this
  ;;   flag and automatically does the right thing.  Without this flag,
  ;;   argv[0] is replaced by the absolute file name of the executable, an
  ;;   observable difference that can cause discrepancies.
  (flags    qemu-platform-flags (default "FP")))  ;string

(define-syntax bv
  (lambda (s)
    "Expand the given string into a bytevector."
    (syntax-case s ()
      ((_ str)
       (string? (syntax->datum #'str))
       (let ((bv (u8-list->bytevector
                  (map char->integer
                       (string->list (syntax->datum #'str))))))
         bv)))))

;;; The platform descriptions below are taken from
;;; 'scripts/qemu-binfmt-conf.sh' in QEMU.

(define %i386
  (qemu-platform
   (name "i386")
   (family "i386")
   (magic (bv "\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x03\x00"))
   (mask (bv "\xff\xff\xff\xff\xff\xfe\xfe\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff"))))

(define %i486
  (qemu-platform
   (name "i486")
   (family "i386")
   (magic (bv "\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x06\x00"))
   (mask (bv "\xff\xff\xff\xff\xff\xfe\xfe\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff"))))

(define %x86_64
  (qemu-platform
   (name "x86_64")
   (family "i386")
   (magic (bv "\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x3e\x00"))
   (mask (bv "\xff\xff\xff\xff\xff\xfe\xfe\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff"))))

(define %alpha
  (qemu-platform
   (name "alpha")
   (family "alpha")
   (magic (bv "\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x26\x90"))
   (mask (bv "\xff\xff\xff\xff\xff\xfe\xfe\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff"))))

(define %arm
  (qemu-platform
   (name "arm")
   (family "arm")
   (magic (bv "\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x28\x00"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff"))))

(define %armeb
  (qemu-platform
   (name "armeb")
   (family "armeb")
   (magic (bv "\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x28"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff"))))

(define %sparc
  (qemu-platform
   (name "sparc")
   (family "sparc")
   (magic (bv "\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x02"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff"))))

(define %sparc32plus
  (qemu-platform
   (name "sparc32plus")
   (family "sparc")
   (magic (bv "\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x12"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff"))))

(define %sparc64
  (qemu-platform
   (name "sparc64")
   (family "sparc")
   (magic (bv "\x7fELF\x02\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x2b"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff"))))

(define %ppc
  (qemu-platform
   (name "ppc")
   (family "ppc")
   (magic (bv "\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x14"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff"))))

(define %ppc64
  (qemu-platform
   (name "ppc64")
   (family "ppc")
   (magic (bv "\x7fELF\x02\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x15"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff"))))

(define %ppc64le
  (qemu-platform
   (name "ppc64le")
   (family "ppcle")
   (magic (bv "\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x15\x00"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\x00"))))

(define %m68k
  (qemu-platform
   (name "m68k")
   (family "m68k")
   (magic (bv "\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x04"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xfe\xfe\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff"))))

;; XXX: We could use the other endianness on a MIPS host.
(define %mips
  (qemu-platform
   (name "mips")
   (family "mips")
   (magic (bv "\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff"))))

(define %mipsel
  (qemu-platform
   (name "mipsel")
   (family "mips")
   (magic (bv "\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff"))))

(define %mipsn32
  (qemu-platform
   (name "mipsn32")
   (family "mips")
   (magic (bv "\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff"))))

(define %mipsn32el
  (qemu-platform
   (name "mipsn32el")
   (family "mips")
   (magic (bv "\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff"))))

(define %mips64
  (qemu-platform
   (name "mips64")
   (family "mips")
   (magic (bv "\x7fELF\x02\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff"))))

(define %mips64el
  (qemu-platform
   (name "mips64el")
   (family "mips")
   (magic (bv "\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff"))))

(define %sh4
  (qemu-platform
   (name "sh4")
   (family "sh4")
   (magic (bv "\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x2a\x00"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff"))))

(define %sh4eb
  (qemu-platform
   (name "sh4eb")
   (family "sh4")
   (magic (bv "\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x2a"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff"))))

(define %s390x
  (qemu-platform
   (name "s390x")
   (family "s390x")
   (magic (bv "\x7fELF\x02\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x16"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff"))))

(define %aarch64
  (qemu-platform
   (name "aarch64")
   (family "arm")
   (magic (bv "\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xb7\x00"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff"))))

(define %aarch64be
  (qemu-platform
   (name "aarch64be")
   (family "armeb")
   (magic (bv "\x7fELF\x02\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xb7"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff"))))

(define %hppa
  (qemu-platform
   (name "hppa")
   (family "hppa")
   (magic (bv "\x7f\x45\x4c\x46\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x0f"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff"))))

(define %riscv32
  (qemu-platform
   (name "riscv32")
   (family "riscv")
   (magic (bv "\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xf3\x00"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff"))))

(define %riscv64
  (qemu-platform
   (name "riscv64")
   (family "riscv")
   (magic (bv "\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xf3\x00"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff"))))

(define %xtensa
  (qemu-platform
   (name "xtensa")
   (family "xtensa")
   (magic (bv "\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x5e\x00"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff"))))

(define %xtensaeb
  (qemu-platform
   (name "xtensaeb")
   (family "xtensaeb")
   (magic (bv "\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x5e"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff"))))

(define %microblaze
  (qemu-platform
   (name "microblaze")
   (family "microblaze")
   (magic (bv "\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xba\xab"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff"))))

(define %microblazeel
  (qemu-platform
   (name "microblazeel")
   (family "microblazeel")
   (magic (bv "\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xab\xba"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff"))))

(define %or1k
  (qemu-platform
   (name "or1k")
   (family "or1k")
   (magic (bv "\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x5c"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff"))))

(define %hexagon
  (qemu-platform
   (name "hexagon")
   (family "hexagon")
   (magic (bv "\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xa4\x00"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff"))))

(define %loongarch64
  (qemu-platform
   (name "loongarch64")
   (family "loongarch")
   (magic (bv "\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x02\x01"))
   (mask (bv "\xff\xff\xff\xff\xff\xff\xff\xfc\x00\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff"))))

;; binfmt_misc: register: failed to install interpreter file /gnu/store/...
;; i486 and aarch64be aren't supported by the qemu-binfmt service.
(define %qemu-platforms
  (list %i386 %x86_64 %alpha %arm %sparc32plus %sparc64 %ppc %ppc64
        %ppc64le %m68k %mips %mipsel %mipsn32 %mipsn32el %mips64 %mips64el %sh4
        %sh4eb %s390x %aarch64 %hppa %riscv32 %riscv64 %xtensa
        %xtensaeb %microblaze %microblazeel %or1k %hexagon %loongarch64))

(define (lookup-qemu-platforms . names)
  "Return the list of QEMU platforms that match NAMES--a list of names such as
\"arm\", \"hppa\", etc."
  (filter (lambda (platform)
            (member (qemu-platform-name platform) names))
          %qemu-platforms))

(define-record-type* <qemu-binfmt-configuration>
  qemu-binfmt-configuration make-qemu-binfmt-configuration
  qemu-binfmt-configuration?
  (qemu        qemu-binfmt-configuration-qemu
               (default qemu))
  (platforms   qemu-binfmt-configuration-platforms
               (default '())))          ;safest default

(define (qemu-platform->binfmt qemu platform)
  "Return a gexp that evaluates to a binfmt string for PLATFORM, using the
given QEMU package."
  (define (bytevector->binfmt-string bv)
    ;; Return a binfmt-friendly string representing BV.  Hex-encode every
    ;; character, in particular because the doc notes "that you must escape
    ;; any NUL bytes; parsing halts at the first one".
    (string-concatenate
     (map (lambda (n)
            (string-append "\\x"
                           (string-pad (number->string n 16) 2 #\0)))
          (bytevector->u8-list bv))))

  (match platform
    (($ <qemu-platform> name family magic mask flags)
     ;; See 'Documentation/binfmt_misc.txt' in the kernel.
     #~(string-append ":qemu-" #$name ":M::"
                      #$(bytevector->binfmt-string magic)
                      ":" #$(bytevector->binfmt-string mask)
                      ":" #$qemu:static "/bin/qemu-" #$name
                      ":" #$flags))))

(define %binfmt-mount-point
  (file-system-mount-point %binary-format-file-system))

(define %binfmt-register-file
  (string-append %binfmt-mount-point "/register"))

(define qemu-binfmt-shepherd-services
  (match-lambda
    (($ <qemu-binfmt-configuration> qemu platforms)
     (list (shepherd-service
            (provision '(qemu-binfmt))
            (documentation "Install binfmt_misc handlers for QEMU.")
            (requirement '(file-system-/proc/sys/fs/binfmt_misc))
            (start #~(lambda ()
                       ;; Register the handlers for all of PLATFORMS.
                       (for-each (lambda (str)
                                   (call-with-output-file
                                       #$%binfmt-register-file
                                     (lambda (port)
                                       (display str port))))
                                 (list
                                  #$@(map (cut qemu-platform->binfmt qemu
                                               <>)
                                          platforms)))
                       #t))
            (stop #~(lambda (_)
                      ;; Unregister the handlers.
                      (for-each (lambda (name)
                                  (let ((file (string-append
                                               #$%binfmt-mount-point
                                               "/qemu-" name)))
                                    (call-with-output-file file
                                      (lambda (port)
                                        (display "-1" port)))))
                                '#$(map qemu-platform-name platforms))
                      #f)))))))

(define qemu-binfmt-service-type
  ;; TODO: Make a separate binfmt_misc service out of this?
  (service-type (name 'qemu-binfmt)
                (extensions
                 (list (service-extension file-system-service-type
                                          (const
                                           (list %binary-format-file-system)))
                       (service-extension shepherd-root-service-type
                                          qemu-binfmt-shepherd-services)))
                (default-value (qemu-binfmt-configuration))
                (description
                 "This service supports transparent emulation of binaries
compiled for other architectures using QEMU and the @code{binfmt_misc}
functionality of the kernel Linux.")))


;;;
;;; QEMU guest agent service.
;;;

(define-configuration qemu-guest-agent-configuration
  (qemu
   (file-like qemu-minimal)
   "QEMU package.")
  (device
   (string "")
   "Path to device or socket used to communicate with the host.  If not
specified, the QEMU default path is used."))

(define (qemu-guest-agent-shepherd-service config)
  (let ((qemu   (qemu-guest-agent-configuration-qemu config))
        (device (qemu-guest-agent-configuration-device config)))
    (list
     (shepherd-service
      (provision '(qemu-guest-agent))

      ;; The service needs to depend on udev, which brings up devices like
      ;; those under /dev/virtio-ports.
      (requirement '(user-processes udev))

      (documentation "Run the QEMU guest agent.")
      (start #~(make-forkexec-constructor
                `(,(string-append #$qemu "/bin/qemu-ga")
                  "--statedir" "/var/run"
                  ,@(if (string-null? #$device)
                        '()
                        (list "--path" #$device)))
                #:log-file "/var/log/qemu-ga.log"))
      (stop #~(make-kill-destructor))))))

(define qemu-guest-agent-service-type
  (service-type
   (name 'qemu-guest-agent)
   (extensions
    (list (service-extension shepherd-root-service-type
                             qemu-guest-agent-shepherd-service)))
   (default-value (qemu-guest-agent-configuration))
   (description "Run the QEMU guest agent.")))


;;;
;;; Secrets for guest VMs.
;;;

(define (secret-service-shepherd-services address)
  "Return a Shepherd service that fetches sensitive material at local PORT,
over TCP.  Reboot upon failure."
  ;; This is a Shepherd service, rather than an activation snippet, to make
  ;; sure it is started once 'networking' is up so it can accept incoming
  ;; connections.
  (list
   (shepherd-service
    (documentation "Fetch secrets from the host at startup time.")
    (provision '(secret-service-client))
    (requirement '(loopback networking))
    (modules '((gnu build secret-service)
               (guix build utils)))
    (start (with-imported-modules '((gnu build secret-service)
                                    (guix build utils))
             #~(lambda ()
                 ;; Since shepherd's output port goes to /dev/log, write this
                 ;; message to stderr so it's visible on the Mach console.
                 (format (current-error-port)
                         "receiving secrets from the host...~%")
                 (force-output (current-error-port))

                 (let ((sent (secret-service-receive-secrets #$address)))
                   (unless sent
                     (sleep 3)
                     (reboot))))))
    (stop #~(const #f)))))

(define secret-service-type
  (service-type
   (name 'secret-service)
   (extensions (list (service-extension shepherd-root-service-type
                                        secret-service-shepherd-services)

                     ;; Make every Shepherd service depend on
                     ;; 'secret-service-client'.
                     (service-extension user-processes-service-type
                                        (const '(secret-service-client)))))
   (description
    "This service fetches secret key and other sensitive material over TCP at
boot time.  This service is meant to be used by virtual machines (VMs) that
can only be accessed by their host.")))

(define* (secret-service-operating-system os
                                          #:optional
                                          (address
                                           #~(make-socket-address
                                              AF_INET INADDR_ANY 1004)))
  "Return an operating system based on OS that includes the secret-service,
that will be listening to receive secret keys on ADDRESS."
  (operating-system
    (inherit os)
    (services
     ;; Turn off SSH and Guix key generation that normally happens during
     ;; activation: that requires entropy and thus takes time during boot, and
     ;; those keys are going to be overwritten by secrets received from the
     ;; host anyway.
     (cons (service secret-service-type address)
           (modify-services (operating-system-user-services os)
             (openssh-service-type
              config => (openssh-configuration
                         (inherit config)
                         (generate-host-keys? #f)))
             (guix-service-type
              config => (guix-configuration
                         (inherit config)
                         (generate-substitute-key? #f))))))))


;;;
;;; Offloading-as-a-service.
;;;

(define-record-type* <virtual-build-machine>
  virtual-build-machine make-virtual-build-machine
  virtual-build-machine?
  this-virtual-build-machine
  (name        virtual-build-machine-name
               (default 'build-vm))
  (image       virtual-build-machine-image
               (thunked)
               (default
                 (virtual-build-machine-default-image
                  this-virtual-build-machine)))
  (qemu        virtual-build-machine-qemu
               (default qemu-minimal))
  (cpu         virtual-build-machine-cpu
               (thunked)
               (default
                 (qemu-cpu-model-for-date
                  (virtual-build-machine-systems this-virtual-build-machine)
                  (virtual-build-machine-date this-virtual-build-machine))))
  (cpu-count   virtual-build-machine-cpu-count
               (default 4))
  (memory-size virtual-build-machine-memory-size  ;integer (MiB)
               (default 2048))
  (date        virtual-build-machine-date
               ;; Default to a date "in the past" assuming a common use case
               ;; is to rebuild old packages.
               (default (make-date 0 0 00 00 01 01 2020 0)))
  (port-forwardings virtual-build-machine-port-forwardings
                    (default
                      `((,%build-vm-ssh-port . 22)
                        (,%build-vm-secrets-port . 1004))))
  (systems     virtual-build-machine-systems
               (default (list (%current-system))))
  (auto-start? virtual-build-machine-auto-start?
               (default #f)))

(define %build-vm-ssh-port
  ;; Default host port where the guest's SSH port is forwarded.
  11022)

(define %build-vm-secrets-port
  ;; Host port to communicate secrets to the build VM.
  ;; FIXME: Anyone on the host can talk to it; use virtio ports or AF_VSOCK
  ;; instead.
  11044)

(define %x86-64-intel-cpu-models
  ;; List of release date/CPU model pairs representing Intel's x86_64 models.
  ;; The list is taken from
  ;; <https://en.wikipedia.org/wiki/List_of_Intel_CPU_microarchitectures>.
  ;; CPU model strings are those found in 'qemu-system-x86_64 -cpu help'.
  (letrec-syntax ((cpu-models (syntax-rules ()
                                ((_ (date model) rest ...)
                                 (alist-cons (date->time-utc
                                              (string->date date "~Y-~m-~d"))
                                             model
                                             (cpu-models rest ...)))
                                ((_)
                                 '()))))
    (reverse
     (cpu-models ("2006-01-01" "core2duo")
                 ("2010-01-01" "Westmere")
                 ("2008-01-01" "Nehalem")
                 ("2011-01-01" "SandyBridge")
                 ("2012-01-01" "IvyBridge")
                 ("2013-01-01" "Haswell")
                 ("2014-01-01" "Broadwell")
                 ("2015-01-01" "Skylake-Client")))))

(define (qemu-cpu-model-for-date systems date)
  "Return the QEMU name of a CPU model for SYSTEMS that was current at DATE."
  (if (any (cut string-prefix? "x86_64-" <>) systems)
      (let ((time (date->time-utc date)))
        (any (match-lambda
               ((release-date . model)
                (and (time<? release-date time)
                     model)))
             %x86-64-intel-cpu-models))
      ;; TODO: Add models for other architectures.
      "host"))

(define (virtual-build-machine-ssh-port config)
  "Return the host port where CONFIG has its VM's SSH port forwarded."
  (any (match-lambda
         ((host-port . 22) host-port)
         (_ #f))
       (virtual-build-machine-port-forwardings config)))

(define (virtual-build-machine-secrets-port config)
  "Return the host port where CONFIG has its VM's secrets port forwarded."
  (any (match-lambda
         ((host-port . 1004) host-port)
         (_ #f))
       (virtual-build-machine-port-forwardings config)))

(define %minimal-vm-syslog-config
  ;; Minimal syslog configuration for a VM.
  (plain-file "vm-syslog.conf" "\
# Log most messages to the console, which goes to the serial
# output, allowing the host to log it.
*.info;auth.notice;authpriv.none       -/dev/console

# The rest.
*.=debug                               -/var/log/debug
authpriv.*;auth.info                    /var/log/secure
"))

(define %virtual-build-machine-operating-system
  (operating-system
    (host-name "build-machine")

    (locale "en_US.utf8")
    (locale-definitions
     ;; Save space by providing only one locale.
     (list (locale-definition (name "en_US.utf8")
                              (source "en_US")
                              (charset "UTF-8"))))

    (bootloader (bootloader-configuration         ;unused
                 (bootloader grub-minimal-bootloader)
                 (targets '("/dev/null"))))
    (file-systems (cons (file-system              ;unused
                          (mount-point "/")
                          (device "none")
                          (type "tmpfs"))
                        %base-file-systems))
    (users (cons (user-account
                  (name "offload")
                  (group "users")
                  (supplementary-groups '("kvm"))
                  (comment "Account used for offloading"))
                 %base-user-accounts))
    (services (cons* (service static-networking-service-type
                              (list %qemu-static-networking))
                     (service openssh-service-type
                              (openssh-configuration
                               (openssh openssh-sans-x)))

                     ;; Run GC once per hour.
                     (simple-service 'perdiodic-gc mcron-service-type
                                     (list #~(job "12 * * * *"
                                                  "guix gc -F 2G")))

                     (modify-services %base-services
                       ;; By default, the secret service introduces a
                       ;; pre-initialized /etc/guix/acl file in the VM.  Thus,
                       ;; clear 'authorize-key?' so that it's not overridden
                       ;; at activation time.
                       ;; Since it's used for offloading, disable substitutes
                       ;; (this avoids network issues).
                       (guix-service-type config =>
                                          (guix-configuration
                                           (inherit config)
                                           (authorize-key? #f)
                                           (use-substitutes? #f)))
                       (syslog-service-type config =>
                                            (syslog-configuration
                                             (config-file
                                              %minimal-vm-syslog-config)))
                       (delete mingetty-service-type)
                       (delete console-font-service-type))))))

(define %default-virtual-build-machine-image-size
  ;; Size of the default disk image of virtual build machines.  It should be
  ;; large enough to let users build a few things.
  (* 20 (expt 2 30)))

(define (virtual-build-machine-default-image config)
  (let* ((type (lookup-image-type-by-name 'mbr-raw))
         (base (os->image %virtual-build-machine-operating-system
                          #:type type)))
    (image (inherit base)
           (name (symbol-append 'build-vm-
                                (virtual-build-machine-name config)))
           (format 'compressed-qcow2)
           (partition-table-type 'mbr)
           (volatile-root? #f)
           (shared-store? #f)
           (size %default-virtual-build-machine-image-size)
           (partitions (match (image-partitions base)
                         ((root)
                          ;; Increase the size of the root partition to match
                          ;; that of the disk image.
                          (let ((root-size (- size (* 50 (expt 2 20)))))
                            (list (partition
                                   (inherit root)
                                   (size root-size))))))))))

(define (virtual-build-machine-account-name config)
  (string-append "build-vm-"
                 (symbol->string
                  (virtual-build-machine-name config))))

(define (virtual-build-machine-accounts config)
  (let ((name (virtual-build-machine-account-name config)))
    (list (user-group (name name) (system? #t))
          (user-account
           (name name)
           (group name)
           (supplementary-groups '("kvm"))
           (comment "Privilege separation user for the virtual build machine")
           (home-directory "/var/empty")
           (shell (file-append shadow "/sbin/nologin"))
           (system? #t)))))

(define (build-vm-shepherd-services config)
  (define transform
    (compose secret-service-operating-system
             operating-system-with-locked-root-account
             operating-system-with-offloading-account
             (lambda (os)
               (virtualized-operating-system os #:full-boot? #t))))

  (define transformed-image
    (let ((base (virtual-build-machine-image config)))
      (image
       (inherit base)
       (operating-system
         (transform (image-operating-system base))))))

  (define command
    (linux-image-startup-command transformed-image
                                 #:qemu
                                 (virtual-build-machine-qemu config)
                                 #:cpu
                                 (virtual-build-machine-cpu config)
                                 #:cpu-count
                                 (virtual-build-machine-cpu-count config)
                                 #:memory-size
                                 (virtual-build-machine-memory-size config)
                                 #:port-forwardings
                                 (virtual-build-machine-port-forwardings
                                  config)
                                 #:date
                                 (virtual-build-machine-date config)))

  (define user
    (virtual-build-machine-account-name config))

  (list (shepherd-service
         (documentation "Run the build virtual machine service.")
         (provision (list (virtual-build-machine-name config)))
         (requirement '(user-processes))
         (modules `((gnu build secret-service)
                    (guix build utils)
                    ,@%default-modules))
         (start
          (with-imported-modules (source-module-closure
                                  '((gnu build secret-service)
                                    (guix build utils)))
            #~(lambda arguments
                (let* ((pid  (fork+exec-command (append #$command arguments)
                                                #:user #$user
                                                #:group "kvm"
                                                #:environment-variables
                                                ;; QEMU tries to write to /var/tmp
                                                ;; by default.
                                                '("TMPDIR=/tmp")))
                       (port #$(virtual-build-machine-secrets-port config))
                       (root #$(virtual-build-machine-secret-root config))
                       (address (make-socket-address AF_INET INADDR_LOOPBACK
                                                     port)))
                  (catch #t
                    (lambda _
                      (if (secret-service-send-secrets address root)
                          pid
                          (begin
                            (kill (- pid) SIGTERM)
                            #f)))
                    (lambda (key . args)
                      (kill (- pid) SIGTERM)
                      (apply throw key args)))))))
         (stop #~(make-kill-destructor))
         (actions
          (list (shepherd-action
                 (name 'configuration)
                 (documentation
                  "Display the configuration of this virtual build machine.")
                 (procedure
                  #~(lambda (_)
                      (format #t "CPU: ~a~%"
                              #$(virtual-build-machine-cpu config))
                      (format #t "number of CPU cores: ~a~%"
                              #$(virtual-build-machine-cpu-count config))
                      (format #t "memory size: ~a MiB~%"
                              #$(virtual-build-machine-memory-size config))
                      (format #t "initial date: ~a~%"
                              #$(date->string
                                 (virtual-build-machine-date config))))))))
         (auto-start? (virtual-build-machine-auto-start? config)))))

(define (authorize-guest-substitutes-on-host)
  "Return a program that authorizes the guest's archive signing key (passed as
an argument) on the host."
  (define not-config?
    (match-lambda
      ('(guix config) #f)
      (('guix _ ...) #t)
      (('gnu _ ...) #t)
      (_ #f)))

  (define run
    (with-extensions (list guile-gcrypt)
      (with-imported-modules `(((guix config) => ,(make-config.scm))
                               ,@(source-module-closure
                                  '((guix pki)
                                    (guix build utils))
                                  #:select? not-config?))
        #~(begin
            (use-modules (ice-9 match)
                         (ice-9 textual-ports)
                         (gcrypt pk-crypto)
                         (guix pki)
                         (guix build utils))

            (match (command-line)
              ((_ guest-config-directory)
               (let ((guest-key (string-append guest-config-directory
                                               "/signing-key.pub")))
                 (if (file-exists? guest-key)
                     ;; Add guest key to the host's ACL.
                     (let* ((key (string->canonical-sexp
                                  (call-with-input-file guest-key
                                    get-string-all)))
                            (acl (public-keys->acl
                                  (cons key (acl->public-keys (current-acl))))))
                       (with-atomic-file-replacement %acl-file
                         (lambda (_ port)
                           (write-acl acl port))))
                     (format (current-error-port)
                             "warning: guest key missing from '~a'~%"
                             guest-key)))))))))

  (program-file "authorize-guest-substitutes-on-host" run))

(define (initialize-build-vm-substitutes)
  "Initialize the Hurd VM's key pair and ACL and store it on the host."
  (define run
    (with-imported-modules '((guix build utils))
      #~(begin
          (use-modules (guix build utils)
                       (ice-9 match))

          (define host-key
            "/etc/guix/signing-key.pub")

          (define host-acl
            "/etc/guix/acl")

          (match (command-line)
            ((_ guest-config-directory)
             (setenv "GUIX_CONFIGURATION_DIRECTORY"
                     guest-config-directory)
             (invoke #+(file-append guix "/bin/guix") "archive"
                     "--generate-key")

             (when (file-exists? host-acl)
               ;; Copy the host ACL.
               (copy-file host-acl
                          (string-append guest-config-directory
                                         "/acl")))

             (when (file-exists? host-key)
               ;; Add the host key to the childhurd's ACL.
               (let ((key (open-fdes host-key O_RDONLY)))
                 (close-fdes 0)
                 (dup2 key 0)
                 (execl #+(file-append guix "/bin/guix")
                        "guix" "archive" "--authorize"))))))))

  (program-file "initialize-build-vm-substitutes" run))

(define* (build-vm-activation secret-directory
                              #:key
                              offloading-ssh-key
                              (offloading? #t))
  (with-imported-modules '((guix build utils))
    #~(begin
        (use-modules (guix build utils))

        (define secret-directory
          #$secret-directory)

        (define ssh-directory
          (string-append secret-directory "/etc/ssh"))

        (define guix-directory
          (string-append secret-directory "/etc/guix"))

        (define offloading-ssh-key
          #$offloading-ssh-key)

        (unless (file-exists? ssh-directory)
          ;; Generate SSH host keys under SSH-DIRECTORY.
          (mkdir-p ssh-directory)
          (invoke #$(file-append openssh "/bin/ssh-keygen")
                  "-A" "-f" secret-directory))

        (unless (or (not #$offloading?)
                    (file-exists? offloading-ssh-key))
          ;; Generate a user SSH key pair for the host to use when offloading
          ;; to the guest.
          (mkdir-p (dirname offloading-ssh-key))
          (invoke #$(file-append openssh "/bin/ssh-keygen")
                  "-t" "ed25519" "-N" ""
                  "-f" offloading-ssh-key)

          ;; Authorize it in the guest for user 'offloading'.
          (let ((authorizations
                 (string-append ssh-directory
                                "/authorized_keys.d/offloading")))
            (mkdir-p (dirname authorizations))
            (copy-file (string-append offloading-ssh-key ".pub")
                       authorizations)
            (chmod (dirname authorizations) #o555)))

        (unless (file-exists? guix-directory)
          (invoke #$(initialize-build-vm-substitutes)
                  guix-directory))

        (when #$offloading?
          ;; Authorize the archive signing key from GUIX-DIRECTORY in the host.
          (invoke #$(authorize-guest-substitutes-on-host) guix-directory)))))

(define (virtual-build-machine-offloading-ssh-key config)
  "Return the name of the file containing the SSH key of user 'offloading'."
  (string-append "/etc/guix/offload/ssh/virtual-build-machine/"
                 (symbol->string
                  (virtual-build-machine-name config))))

(define (virtual-build-machine-activation config)
  "Return a gexp to activate the build VM according to CONFIG."
  (build-vm-activation (virtual-build-machine-secret-root config)
                       #:offloading? #t
                       #:offloading-ssh-key
                       (virtual-build-machine-offloading-ssh-key config)))

(define (virtual-build-machine-secret-root config)
  (string-append "/etc/guix/virtual-build-machines/"
                 (symbol->string
                  (virtual-build-machine-name config))))

(define (check-vm-availability config)
  "Return a Scheme file that evaluates to true if the service corresponding to
CONFIG, a <virtual-build-machine>, is up and running."
  (define service-name
    (virtual-build-machine-name config))

  (scheme-file "check-build-vm-availability.scm"
               #~(begin
                   (use-modules (gnu services herd)
                                (srfi srfi-34))

                   (guard (c ((service-not-found-error? c) #f))
                     (->bool (live-service-running
                              (current-service '#$service-name)))))))

(define (build-vm-guix-extension config)
  (define vm-ssh-key
    (string-append
     (virtual-build-machine-secret-root config)
     "/etc/ssh/ssh_host_ed25519_key.pub"))

  (define host-ssh-key
    (virtual-build-machine-offloading-ssh-key config))

  (guix-extension
   (build-machines
    (list #~(if (primitive-load #$(check-vm-availability config))
                (list (build-machine
                       (name "localhost")
                       (port #$(virtual-build-machine-ssh-port config))
                       (systems
                        '#$(virtual-build-machine-systems config))
                       (user "offloading")
                       (host-key (call-with-input-file #$vm-ssh-key
                                   (@ (ice-9 textual-ports)
                                      get-string-all)))
                       (private-key #$host-ssh-key)))
                '())))))

(define virtual-build-machine-service-type
  (service-type
   (name 'build-vm)
   (extensions (list (service-extension shepherd-root-service-type
                                        build-vm-shepherd-services)
                     (service-extension guix-service-type
                                        build-vm-guix-extension)
                     (service-extension account-service-type
                                        virtual-build-machine-accounts)
                     (service-extension activation-service-type
                                        virtual-build-machine-activation)))
   (description
    "Create a @dfn{virtual build machine}: a virtual machine (VM) that builds
can be offloaded to.  By default, the virtual machine starts with a clock
running at some point in the past.")
   (default-value (virtual-build-machine))))


;;;
;;; The Hurd in VM service: a Childhurd.
;;;

(define (operating-system-with-offloading-account os)
  (define accounts
    (list (user-group
           (name "offloading")
           (system? #t))
          (user-account
           (name "offloading")
           (group "offloading")
           (system? #t)
           (comment "Offloading privilege separation user")
           (home-directory "/var/run/offloading")
           (shell (file-append bash-minimal "/bin/sh")))))

  (operating-system
    (inherit os)
    (services (cons (simple-service 'offloading-account
                                    account-service-type
                                    accounts)
                    (operating-system-user-services os)))))

(define (operating-system-with-locked-root-account os)
  "Return OS with a 'root' account whose password is uninitialized, thereby
preventing password-based authentication as 'root'."
  (define root
    ;; %ROOT-ACCOUNT has an empty password; change that to an uninitialized
    ;; password.
    (user-account
     (inherit %root-account)
     (password #f)))

  (operating-system
    (inherit os)
    (users (cons root (operating-system-users os)))))

(define %hurd-vm-operating-system
  (operating-system
    (inherit %hurd-default-operating-system)
    (host-name "childhurd")
    (timezone "Europe/Amsterdam")
    (bootloader (bootloader-configuration
                 (bootloader grub-minimal-bootloader)
                 (targets '("/dev/vda"))
                 (timeout 0)))
    (packages (cons* gdb-minimal
                     (operating-system-packages
                      %hurd-default-operating-system)))
    (services (cons*
               (service openssh-service-type
                        (openssh-configuration
                         (openssh openssh-sans-x)
                         (use-pam? #f)
                         (permit-root-login 'prohibit-password)
                         (allow-empty-passwords? #t)
                         (password-authentication? #t)))

               ;; By default, the secret service introduces a pre-initialized
               ;; /etc/guix/acl file in the childhurd.  Thus, clear
               ;; 'authorize-key?' so that it's not overridden at activation
               ;; time.
               (modify-services %base-services/hurd
                 (guix-service-type config =>
                                    (guix-configuration
                                     (inherit config)
                                     (authorize-key? #f))))))))

(define-record-type* <hurd-vm-configuration>
  hurd-vm-configuration make-hurd-vm-configuration
  hurd-vm-configuration?
  (os          hurd-vm-configuration-os                 ;<operating-system>
               (default %hurd-vm-operating-system))
  (qemu        hurd-vm-configuration-qemu               ;file-like
               (default qemu-minimal))
  (image       hurd-vm-configuration-image              ;<image>
               (thunked)
               (default (hurd-vm-disk-image this-record)))
  (disk-size   hurd-vm-configuration-disk-size          ;number or 'guess
               (default 'guess))
  (memory-size hurd-vm-configuration-memory-size        ;number
               (default 2048))
  (options     hurd-vm-configuration-options            ;list of string
               (default `("--snapshot")))
  (id          hurd-vm-configuration-id                 ;#f or integer [1..]
               (default #f))
  (net-options hurd-vm-configuration-net-options        ;list of string
               (thunked)
               (default (hurd-vm-net-options this-record)))
  (offloading? hurd-vm-configuration-offloading?        ;Boolean
               (default #t))
  (secret-root hurd-vm-configuration-secret-root        ;string
               (default "/etc/childhurd")))

(define (hurd-vm-disk-image config)
  "Return a disk-image for the Hurd according to CONFIG.  The secret-service
is added to the OS specified in CONFIG."
  (define transform
    (compose secret-service-operating-system
             ;; When offloading is enabled, (1) add the 'offloading' account,
             ;; and (2) prevent users from logging in as 'root' without a
             ;; password as this would allow any user on the host to populate
             ;; the host's store indirectly (for example by logging in as root
             ;; in the Hurd VM over VNC).
             (if (hurd-vm-configuration-offloading? config)
                 (compose operating-system-with-locked-root-account
                          operating-system-with-offloading-account)
                 identity)))

  (let* ((os        (transform (hurd-vm-configuration-os config)))
         (disk-size (hurd-vm-configuration-disk-size config))
         (type      (lookup-image-type-by-name 'hurd-qcow2))
         (os->image (image-type-constructor type)))
    (image (inherit (os->image os))
           (size disk-size))))

(define (hurd-vm-port config base)
  "Return the forwarded vm port for this childhurd config."
  (let ((id (or (hurd-vm-configuration-id config) 0)))
    (+ base (* 1000 id))))
(define %hurd-vm-secrets-port 11004)
(define %hurd-vm-ssh-port 10022)
(define %hurd-vm-vnc-port 15900)

(define (hurd-vm-net-options config)
  `("--device" "rtl8139,netdev=net0"
    "--netdev"
    ,(string-append "user,id=net0"
                    ",hostfwd=tcp:127.0.0.1:"
                    (number->string (hurd-vm-port config %hurd-vm-secrets-port))
                    "-:1004"
                    ",hostfwd=tcp:127.0.0.1:"
                    (number->string (hurd-vm-port config %hurd-vm-ssh-port))
                    "-:22"
                    ",hostfwd=tcp:127.0.0.1:"
                    (number->string (hurd-vm-port config %hurd-vm-vnc-port))
                    "-:5900")))

(define (hurd-vm-shepherd-service config)
  "Return a <shepherd-service> for a Hurd in a Virtual Machine with CONFIG."

  (let ((image       (hurd-vm-configuration-image config))
        (qemu        (hurd-vm-configuration-qemu config))
        (memory-size (hurd-vm-configuration-memory-size config))
        (options     (hurd-vm-configuration-options config))
        (id          (hurd-vm-configuration-id config))
        (net-options (hurd-vm-configuration-net-options config))
        (provisions  '(hurd-vm childhurd)))

    (define vm-command
      ;; XXX: Use the x86_64 emulator instead of the i386 one to work around
      ;; "Bad ram pointer" issues: <https://issues.guix.gnu.org/66053>.
      #~(append (list #$(file-append qemu "/bin/qemu-system-x86_64")
                      "-m" (number->string #$memory-size)
                      #$@net-options
                      #$@options
                      "--hda" #+(system-image image)

                      ;; Cause the service to be respawned if the guest
                      ;; reboots (it can reboot for instance if it did not
                      ;; receive valid secrets, or if it crashed.)
                      "--no-reboot")
                (if (file-exists? "/dev/kvm")
                    '("--enable-kvm")
                    '())))

    (list
     (shepherd-service
      (documentation "Run the Hurd in a Virtual Machine: a Childhurd.")
      (provision (if id
                     (map
                      (cute symbol-append <>
                            (string->symbol (number->string id)))
                      provisions)
                     provisions))
      (requirement '(loopback networking user-processes))
      (start
       (with-imported-modules
           (source-module-closure '((gnu build secret-service)
                                    (guix build utils)))
         #~(lambda ()
             (let* ((pid  (fork+exec-command #$vm-command
                                             #:user "childhurd"
                                             ;; XXX TODO: use "childhurd" after
                                             ;; updating Shepherd
                                             #:group "kvm"
                                             #:environment-variables
                                             ;; QEMU tries to write to /var/tmp
                                             ;; by default.
                                             '("TMPDIR=/tmp")))
                    (port #$(hurd-vm-port config %hurd-vm-secrets-port))
                    (root #$(hurd-vm-configuration-secret-root config))
                    (address (make-socket-address AF_INET INADDR_LOOPBACK
                                                  port)))
               (catch #t
                 (lambda _
                   ;; XXX: 'secret-service-send-secrets' won't complete until
                   ;; the guest has booted and its secret service server is
                   ;; running, which could take 20+ seconds during which PID 1
                   ;; is stuck waiting.
                   (if (secret-service-send-secrets address root)
                       pid
                       (begin
                         (kill (- pid) SIGTERM)
                         #f)))
                 (lambda (key . args)
                   (kill (- pid) SIGTERM)
                   (apply throw key args)))))))
      (modules `((gnu build secret-service)
                 (guix build utils)
                 ,@%default-modules))
      (stop  #~(make-kill-destructor))))))

(define %hurd-vm-accounts
  (list (user-group (name "childhurd") (system? #t))
        (user-account
         (name "childhurd")
         (group "childhurd")
         (supplementary-groups '("kvm"))
         (comment "Privilege separation user for the childhurd")
         (home-directory "/var/empty")
         (shell (file-append shadow "/sbin/nologin"))
         (system? #t))))

(define (hurd-vm-activation config)
  "Return a gexp to activate the Hurd VM according to CONFIG."
  (build-vm-activation (hurd-vm-configuration-secret-root config)
                       #:offloading?
                       (hurd-vm-configuration-offloading? config)
                       #:offloading-ssh-key
                       (hurd-vm-configuration-offloading-ssh-key config)))

(define (hurd-vm-configuration-offloading-ssh-key config)
  "Return the name of the file containing the SSH key of user 'offloading'."
  (string-append "/etc/guix/offload/ssh/childhurd"
                 (or (and=> (hurd-vm-configuration-id config)
                            number->string)
                     "")))

(define (hurd-vm-guix-extension config)
  "When offloading is enabled, add this childhurd to the list of offlading
machines in /etc/guix/machines.scm."
  (if (hurd-vm-configuration-offloading? config)
      (let* ((image (hurd-vm-configuration-image config))
             (platform (image-platform image))
             (system (platform-system platform))
             (vm-ssh-key (string-append
                          (hurd-vm-configuration-secret-root config)
                          "/etc/ssh/ssh_host_ed25519_key.pub"))
             (host-ssh-key (hurd-vm-configuration-offloading-ssh-key config)))
        (guix-extension
         (build-machines
          (list #~(build-machine
                   (name "localhost")
                   (port #$(hurd-vm-port config %hurd-vm-ssh-port))
                   (systems '(#$system))
                   (host-key (call-with-input-file #$vm-ssh-key
                               (@ (ice-9 textual-ports)
                                  get-string-all)))
                   (user "offloading")
                   (private-key #$host-ssh-key))))))
      (guix-extension)))

(define hurd-vm-service-type
  (service-type
   (name 'hurd-vm)
   (extensions (list (service-extension shepherd-root-service-type
                                        hurd-vm-shepherd-service)
                     (service-extension account-service-type
                                        (const %hurd-vm-accounts))
                     (service-extension guix-service-type
                                        hurd-vm-guix-extension)
                     (service-extension activation-service-type
                                        hurd-vm-activation)))
   (default-value (hurd-vm-configuration))
   (description
    "Provide a virtual machine (VM) running GNU/Hurd, also known as a
@dfn{childhurd}.")))