unofficial mirror of guix-patches@gnu.org 
 help / color / mirror / code / Atom feed
blob 8a4002e072462e9249b030316529a2b775d014b0 53586 bytes (raw)
name: gnu/services.scm 	 # note: path name is non-authoritative(*)

   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
 
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2015-2024 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2016 Chris Marusich <cmmarusich@gmail.com>
;;; Copyright © 2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
;;; Copyright © 2020, 2021 Ricardo Wurmus <rekado@elephly.net>
;;; Copyright © 2021 raid5atemyhomework <raid5atemyhomework@protonmail.com>
;;; Copyright © 2020 Christine Lemmer-Webber <cwebber@dustycloud.org>
;;; Copyright © 2020, 2021 Brice Waegeneire <brice@waegenei.re>
;;; Copyright © 2022 Tobias Geerinckx-Rice <me@tobias.gr>
;;; Copyright © 2023 Brian Cully <bjc@spork.org>
;;; Copyright © 2024 Nicolas Graves <ngraves@ngraves.fr>
;;;
;;; 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)
  #:use-module (guix gexp)
  #:use-module (guix monads)
  #:use-module (guix store)
  #:use-module (guix records)
  #:use-module (guix profiles)
  #:use-module (guix discovery)
  #:use-module (guix combinators)
  #:use-module (guix channels)
  #:use-module (guix describe)
  #:use-module (guix sets)
  #:use-module (guix ui)
  #:use-module (guix diagnostics)
  #:autoload   (guix openpgp) (openpgp-format-fingerprint)
  #:use-module (guix modules)
  #:use-module (guix packages)
  #:use-module (guix utils)
  #:use-module (guix deprecation)
  #:use-module (gnu packages base)
  #:use-module (gnu packages bash)
  #:use-module (gnu packages hurd)
  #:use-module (gnu packages linux)
  #:use-module (gnu system privilege)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-9)
  #:use-module (srfi srfi-9 gnu)
  #:use-module (srfi srfi-26)
  #:use-module (srfi srfi-34)
  #:use-module (srfi srfi-35)
  #:use-module (srfi srfi-71)
  #:use-module (ice-9 vlist)
  #:use-module (ice-9 match)
  #:autoload   (ice-9 pretty-print) (pretty-print)
  #:export (service-extension
            service-extension?
            service-extension-target
            service-extension-compute

            service-type
            service-type?
            service-type-name
            service-type-extensions
            service-type-compose
            service-type-extend
            service-type-default-value
            service-type-description
            service-type-location

            %service-type-path
            fold-service-types
            lookup-service-types

            service
            service?
            service-kind
            service-value
            service-parameters                    ;deprecated

            simple-service
            modify-services
            service-back-edges
            instantiate-missing-services
            fold-services

            remove-service-extensions
            for-home
            for-home?

            validate-service-list

            service-error?
            missing-value-service-error?
            missing-value-service-error-type
            missing-value-service-error-location
            missing-target-service-error?
            missing-target-service-error-service
            missing-target-service-error-target-type
            ambiguous-target-service-error?
            ambiguous-target-service-error-service
            ambiguous-target-service-error-target-type

            system-service-type
            provenance-service-type
            sexp->system-provenance
            system-provenance
            boot-service-type
            cleanup-service-type
            activation-service-type
            activation-service->script
            %linux-bare-metal-service
            %hurd-rc-script
            %hurd-startup-service
            special-files-service-type
            extra-special-file
            etc-service-type
            etc-directory
            privileged-program-service-type
            setuid-program-service-type ; deprecated
            profile-service-type
            firmware-service-type
            gc-root-service-type
            linux-builder-service-type
            linux-builder-configuration
            linux-builder-configuration?
            linux-builder-configuration-kernel
            linux-builder-configuration-modules
            linux-loadable-module-service-type

            %boot-service
            %activation-service
            etc-service)  ; deprecated
  #:re-export (;; Note: Re-export 'delete' to allow for proper syntax matching
               ;; in 'modify-services' forms.  See
               ;; <https://debbugs.gnu.org/cgi/bugreport.cgi?bug=26805#16>.
               delete))

;;; Comment:
;;;
;;; This module defines a broad notion of "service types" and "services."
;;;
;;; A service type describe how its instances extend instances of other
;;; service types.  For instance, some services extend the instance of
;;; ACCOUNT-SERVICE-TYPE by providing it with accounts and groups to create;
;;; others extend SHEPHERD-ROOT-SERVICE-TYPE by passing it instances of
;;; <shepherd-service>.
;;;
;;; When applicable, the service type defines how it can itself be extended,
;;; by providing one procedure to compose extensions, and one procedure to
;;; extend itself.
;;;
;;; A notable service type is SYSTEM-SERVICE-TYPE, which has a single
;;; instance, which is the root of the service DAG.  Its value is the
;;; derivation that produces the 'system' directory as returned by
;;; 'operating-system-derivation'.
;;;
;;; The 'fold-services' procedure can be passed a list of procedures, which it
;;; "folds" by propagating extensions down the graph; it returns the root
;;; service after the applying all its extensions.
;;;
;;; Code:

(define-record-type <service-extension>
  (service-extension target compute)
  service-extension?
  (target  service-extension-target)              ;<service-type>
  (compute service-extension-compute))            ;params -> params

(define &no-default-value
  ;; Value used to denote service types that have no associated default value.
  '(no default value))

(define-record-type* <service-type> service-type make-service-type
  service-type?
  (name       service-type-name)                  ;symbol (for debugging)

  ;; Things extended by services of this type.
  (extensions service-type-extensions)            ;list of <service-extensions>

  ;; Given a list of extensions, "compose" them.
  (compose    service-type-compose                ;list of Any -> Any
              (default #f))

  ;; Extend the services' own parameters with the extension composition.
  (extend     service-type-extend                 ;list of Any -> parameters
              (default #f))

  ;; Optional default value for instances of this type.
  (default-value service-type-default-value       ;Any
                 (default &no-default-value))

  ;; Meta-data.
  (description  service-type-description)         ;string
  (location     service-type-location             ;<location>
                (default (and=> (current-source-location)
                                source-properties->location))
                (innate)))

(define (write-service-type type port)
  (format port "#<service-type ~a ~a>"
          (service-type-name type)
          (number->string (object-address type) 16)))

(set-record-type-printer! <service-type> write-service-type)

(define %distro-root-directory
  ;; Absolute file name of the module hierarchy.
  (dirname (search-path %load-path "guix.scm")))

(define %service-type-path
  ;; Search path for service types.
  (make-parameter `((,%distro-root-directory . "gnu/services")
                    (,%distro-root-directory . "gnu/system"))))

(define (all-service-modules)
  "Return the default set of service modules."
  (cons (resolve-interface '(gnu services))
        (all-modules (%service-type-path)
                     #:warn warn-about-load-error)))

(define* (fold-service-types proc seed
                             #:optional
                             (modules (all-service-modules)))
  "For each service type exported by one of MODULES, call (PROC RESULT).  SEED
is used as the initial value of RESULT."
  (fold-module-public-variables (lambda (object result)
                                  (if (service-type? object)
                                      (proc object result)
                                      result))
                                seed
                                modules))

(define lookup-service-types
  (let ((table
         (delay (fold-service-types (lambda (type result)
                                      (vhash-consq (service-type-name type)
                                                   type result))
                                    vlist-null))))
    (lambda (name)
      "Return the list of services with the given NAME (a symbol)."
      (vhash-foldq* cons '() name (force table)))))

;; Services of a given type.
(define-record-type <service>
  (make-service type value)
  service?
  (type       service-kind)
  (value      service-value))

(define-syntax service
  (syntax-rules ()
    "Return a service instance of TYPE.  The service value is VALUE or, if
omitted, TYPE's default value."
    ((_ type value)
     (make-service type value))
    ((_ type)
     (%service-with-default-value (current-source-location)
                                  type))))

(define (%service-with-default-value location type)
  "Return a instance of service type TYPE with its default value, if any.  If
TYPE does not have a default value, an error is raised."
  ;; TODO: Currently this is a run-time error but with a little bit macrology
  ;; we could turn it into an expansion-time error.
  (let ((default (service-type-default-value type)))
    (if (eq? default &no-default-value)
        (let ((location (source-properties->location location)))
          (raise
           (make-compound-condition
            (condition
             (&missing-value-service-error (type type) (location location)))
            (formatted-message (G_ "~a: no value specified \
for service of type '~a'")
                               (location->string location)
                               (service-type-name type)))))
        (service type default))))

(define-condition-type &service-error &error
  service-error?)

(define-condition-type &missing-value-service-error &service-error
  missing-value-service-error?
  (type     missing-value-service-error-type)
  (location missing-value-service-error-location))


\f
;;;
;;; Helpers.
;;;

(define service-parameters
  ;; Deprecated alias.
  service-value)

(define (simple-service name target value)
  "Return a service that extends TARGET with VALUE.  This works by creating a
singleton service type NAME, of which the returned service is an instance."
  (let* ((extension (service-extension target identity))
         (type      (service-type (name name)
                                  (extensions (list extension))
                                  (description "This is a simple service."))))
    (service type value)))

(define-syntax clause-alist
  (syntax-rules (=> delete)
    "Build an alist of clauses.  Each element has the form (KIND PROC LOC)
where PROC is the service transformation procedure to apply for KIND, and LOC
is the source location information."
    ((_ (delete kind) rest ...)
     (cons (list kind
                 (lambda (service)
                   #f)
                 (current-source-location))
           (clause-alist rest ...)))
    ((_ (kind param => exp ...) rest ...)
     (cons (list kind
                 (lambda (svc)
                   (let ((param (service-value svc)))
                     (service (service-kind svc)
                              (begin exp ...))))
                 (current-source-location))
           (clause-alist rest ...)))
    ((_)
     '())))

(define (apply-clauses clauses service deleted-services)
  "Apply CLAUSES, an alist as returned by 'clause-alist', to SERVICE.  An
exception is raised if a clause attempts to modify a service
present in DELETED-SERVICES."
  (define (raise-if-deleted kind properties)
    (match (find (match-lambda
                   ((deleted-kind _)
                    (eq? kind deleted-kind)))
                 deleted-services)
      ((_ deleted-properties)
       (raise (make-compound-condition
               (condition
                (&error-location
                 (location (source-properties->location properties))))
               (formatted-message
                (G_ "modify-services: service '~a' was deleted here: ~a")
                (service-type-name kind)
                (source-properties->location deleted-properties)))))
      (_ #t)))

  (match clauses
    (((kind proc properties) . rest)
     (raise-if-deleted kind properties)
     (if (eq? (and service (service-kind service)) kind)
         (let ((new-service (proc service)))
           (apply-clauses rest new-service
                          (if new-service
                              deleted-services
                              (cons (list kind properties)
                                    deleted-services))))
         (apply-clauses rest service deleted-services)))
    (()
     service)))

(define (%modify-services services clauses)
  "Apply CLAUSES, an alist as returned by 'clause-alist', to SERVICES.  An
exception is raised if a clause attempts to modify a missing service."
  (define (raise-if-not-found clause)
    (match clause
      ((kind _ properties)
       (unless (find (lambda (service)
                       (eq? kind (service-kind service)))
                     services)
         (raise (make-compound-condition
                 (condition
                  (&error-location
                   (location (source-properties->location properties))))
                 (formatted-message
                  (G_ "modify-services: service '~a' not found in service list")
                  (service-type-name kind))))))))

  (for-each raise-if-not-found clauses)
  (reverse (filter-map identity
                       (fold (lambda (service services)
                               (cons (apply-clauses clauses service '())
                                     services))
                             '()
                             services))))

(define-syntax modify-services
  (syntax-rules ()
    "Modify the services listed in SERVICES according to CLAUSES and return
the resulting list of services.  Each clause must have the form:

  (TYPE VARIABLE => BODY)

where TYPE is a service type, such as 'guix-service-type', and VARIABLE is an
identifier that is bound within BODY to the value of the service of that
TYPE.

Clauses can also remove services of a given type:

  (delete TYPE)

Consider this example:

  (modify-services %base-services
    (guix-service-type config =>
                       (guix-configuration
                        (inherit config)
                        (use-substitutes? #f)
                        (extra-options '(\"--gc-keep-derivations\"))))
    (mingetty-service-type config =>
                           (mingetty-configuration
                            (inherit config)
                            (motd (plain-file \"motd\" \"Hi there!\"))))
    (delete udev-service-type))

It changes the configuration of the GUIX-SERVICE-TYPE instance, and that of
all the MINGETTY-SERVICE-TYPE instances, and it deletes instances of the
UDEV-SERVICE-TYPE."
    ((_ services clauses ...)
     (%modify-services services (clause-alist clauses ...)))))

\f
;;;
;;; Core services.
;;;

(define (system-derivation entries mextensions)
  "Return as a monadic value the derivation of the 'system' directory
containing the given entries."
  (mlet %store-monad ((extensions (mapm/accumulate-builds identity
                                                          mextensions)))
    (lower-object
     (file-union "system"
                 (append entries (concatenate extensions))))))

(define system-service-type
  ;; This is the ultimate service type, the root of the service DAG.  The
  ;; service of this type is extended by monadic name/item pairs.  These items
  ;; end up in the "system directory" as returned by
  ;; 'operating-system-derivation'.
  (service-type (name 'system)
                (extensions '())
                (compose identity)
                (extend system-derivation)
                (description
                 "Build the operating system top-level directory, which in
turn refers to everything the operating system needs: its kernel, initrd,
system profile, boot script, and so on.")))

(define (compute-boot-script _ gexps)
  ;; Reverse GEXPS so that extensions appear in the boot script in the right
  ;; order.  That is, user extensions would come first, and extensions added
  ;; by 'essential-services' (e.g., running shepherd) are guaranteed to come
  ;; last.
  (gexp->file "boot"
              ;; Clean up and activate the system, then spawn shepherd.
              #~(begin #$@(reverse gexps))))

(define (boot-script-entry mboot)
  "Return, as a monadic value, an entry for the boot script in the system
directory."
  (mlet %store-monad ((boot mboot))
    (return `(("boot" ,boot)))))

(define boot-service-type
  ;; The service of this type is extended by being passed gexps.  It
  ;; aggregates them in a single script, as a monadic value, which becomes its
  ;; value.
  (service-type (name 'boot)
                (extensions
                 (list (service-extension system-service-type
                                          boot-script-entry)))
                (compose identity)
                (extend compute-boot-script)
                (default-value #f)
                (description
                 "Produce the operating system's boot script, which is spawned
by the initrd once the root file system is mounted.")))

(define %boot-service
  ;; The service that produces the boot script.
  (service boot-service-type #t))

\f
;;;
;;; Provenance tracking.
;;;

(define (object->pretty-string obj)
  "Like 'object->string', but using 'pretty-print'."
  (call-with-output-string
    (lambda (port)
      (pretty-print obj port))))

(define (channel->code channel)
  "Return code to build CHANNEL, ready to be dropped in a 'channels.scm'
file."
  ;; Since the 'introduction' field is backward-incompatible, and since it's
  ;; optional when using the "official" 'guix channel, include it if and only
  ;; if we're referring to a different channel.
  (let ((intro (and (not (equal? (list channel) %default-channels))
                    (channel-introduction channel))))
    `(channel (name ',(channel-name channel))
              (url ,(channel-url channel))
              (branch ,(channel-branch channel))
              (commit ,(channel-commit channel))
              ,@(if intro
                    `((introduction
                       (make-channel-introduction
                        ,(channel-introduction-first-signed-commit intro)
                        (openpgp-fingerprint
                         ,(openpgp-format-fingerprint
                           (channel-introduction-first-commit-signer
                            intro))))))
                    '()))))

(define (channel->sexp channel)
  "Return an sexp describing CHANNEL.  The sexp is _not_ code and is meant to
be parsed by tools; it's potentially more future-proof than code."
  ;; TODO: Add CHANNEL's introduction.  Currently we can't do that because
  ;; older 'guix system describe' expect exactly name/url/branch/commit
  ;; without any additional fields.
  `(channel (name ,(channel-name channel))
            (url ,(channel-url channel))
            (branch ,(channel-branch channel))
            (commit ,(channel-commit channel))))

(define (sexp->channel sexp)
  "Return the channel corresponding to SEXP, an sexp as found in the
\"provenance\" file produced by 'provenance-service-type'."
  (match sexp
    (('channel ('name name)
               ('url url)
               ('branch branch)
               ('commit commit)
               rest ...)
     ;; XXX: In the future REST may include a channel introduction.
     (channel (name name) (url url)
              (branch branch) (commit commit)))))

(define (provenance-file channels config-file)
  "Return a 'provenance' file describing CHANNELS, a list of channels, and
CONFIG-FILE, which can be either #f or a <local-file> containing the OS
configuration being used."
  (scheme-file "provenance"
               #~(provenance
                  (version 0)
                  (channels #+@(if channels
                                   (map channel->sexp channels)
                                   '()))
                  (configuration-file #+config-file))))

(define (provenance-entry config-file)
  "Return system entries describing the operating system provenance: the
channels in use and CONFIG-FILE, if it is true."
  (define channels
    (current-channels))

  (mbegin %store-monad
    (let ((config-file (cond ((string? config-file)
                              ;; CONFIG-FILE has been passed typically via
                              ;; 'guix system reconfigure CONFIG-FILE' so we
                              ;; can assume it's valid: tell 'local-file' to
                              ;; not emit a warning.
                              (local-file (assume-valid-file-name config-file)
                                          "configuration.scm"))
                             ((not config-file)
                              #f)
                             (else
                              config-file))))
      (return `(("provenance" ,(provenance-file channels config-file))
                ,@(if channels
                      `(("channels.scm"
                         ,(plain-file "channels.scm"
                                      (object->pretty-string
                                       `(list
                                         ,@(map channel->code channels))))))
                      '())
                ,@(if config-file
                      `(("configuration.scm" ,config-file))
                      '()))))))

(define provenance-service-type
  (service-type (name 'provenance)
                (extensions
                 (list (service-extension system-service-type
                                          provenance-entry)))
                (default-value #f)                ;the OS config file
                (description
                 "Store provenance information about the system in the system
itself: the channels used when building the system, and its configuration
file, when available.")))

(define (sexp->system-provenance sexp)
  "Parse SEXP, an s-expression read from /run/current-system/provenance or
similar, and return two values: the list of channels listed therein, and the
OS configuration file or #f."
  (match sexp
    (('provenance ('version 0)
                  ('channels channels ...)
                  ('configuration-file config-file))
     (values (map sexp->channel channels)
             config-file))
    (_
     (values '() #f))))

(define (system-provenance system)
  "Given SYSTEM, the file name of a system generation, return two values: the
list of channels SYSTEM is built from, and its configuration file.  If that
information is missing, return the empty list (for channels) and possibly
#false (for the configuration file)."
  (catch 'system-error
    (lambda ()
      (sexp->system-provenance
       (call-with-input-file (string-append system "/provenance")
         read)))
    (lambda _
      (values '() #f))))
\f
;;;
;;; Cleanup.
;;;

(define (cleanup-gexp _)
  "Return a gexp to clean up /tmp and similar places upon boot."
  (with-imported-modules '((guix build utils))
    #~(begin
        (use-modules (guix build utils))

        ;; Clean out /tmp, /var/run, and /run.
        ;;
        ;; XXX This needs to happen before service activations, so it
        ;; has to be here, but this also implicitly assumes that /tmp
        ;; and /var/run are on the root partition.
        (letrec-syntax ((fail-safe (syntax-rules ()
                                     ((_ exp rest ...)
                                      (begin
                                        (catch 'system-error
                                          (lambda () exp)
                                          (const #f))
                                        (fail-safe rest ...)))
                                     ((_)
                                      #t))))
          ;; Ignore I/O errors so the system can boot.
          (fail-safe
           ;; Remove stale Shadow lock files as they would lead to
           ;; failures of 'useradd' & co.
           (delete-file "/etc/group.lock")
           (delete-file "/etc/passwd.lock")
           (delete-file "/etc/.pwd.lock")         ;from 'lckpwdf'

           ;; Force file names to be decoded as UTF-8.  See
           ;; <https://bugs.gnu.org/26353>.
           (setenv "GUIX_LOCPATH"
                   #+(file-append
                      (libc-utf8-locales-for-target (%current-system))
                      "/lib/locale"))
           (setlocale LC_CTYPE "en_US.utf8")
           (delete-file-recursively "/tmp")
           (delete-file-recursively "/var/run")
           (delete-file-recursively "/run")

           ;; Note: The second argument to 'mkdir' is and'ed with umask,
           ;; hence the 'chmod' calls.
           (mkdir "/tmp" #o1777)
           (chmod "/tmp" #o1777)
           (mkdir "/var/run" #o755)
           (chmod "/var/run" #o755)
           (mkdir "/run" #o755)
           (chmod "/var/run" #o755))))))

(define cleanup-service-type
  ;; Service that cleans things up in /tmp and similar.
  (service-type (name 'cleanup)
                (extensions
                 (list (service-extension boot-service-type
                                          cleanup-gexp)))
                (description
                 "Delete files from @file{/tmp}, @file{/var/run}, and other
temporary locations at boot time.")))

(define* (activation-service->script service)
  "Return as a monadic value the activation script for SERVICE, a service of
ACTIVATION-SCRIPT-TYPE."
  (activation-script (service-value service)))

(define (activation-script gexps)
  "Return the system's activation script, which evaluates GEXPS."
  (define actions
    (map (cut program-file "activate-service.scm" <>) gexps))

  (program-file "activate.scm"
                (with-imported-modules (source-module-closure
                                        '((gnu build activation)
                                          (guix build utils)))
                  #~(begin
                      (use-modules (gnu build activation)
                                   (guix build utils))

                      (mkdir-p "/var/run")
                      ;; Make sure the user accounting database exists.  If it
                      ;; does not exist, 'setutxent' does not create it and
                      ;; thus there is no accounting at all.
                      (close-port (open-file "/var/run/utmpx" "a0"))

                      ;; Same for 'wtmp', which is populated by mingetty et
                      ;; al.
                      (mkdir-p "/var/log")
                      (close-port (open-file "/var/log/wtmp" "a0"))

                      ;; Set up /run/current-system.  Among other things this
                      ;; sets up locales, which the activation snippets
                      ;; executed below may expect.
                      (activate-current-system)

                      ;; Run the services' activation snippets.
                      ;; TODO: Use 'load-compiled'.
                      (for-each primitive-load '#$actions)))))

(define (gexps->activation-gexp gexps)
  "Return a gexp that runs the activation script containing GEXPS."
  #~(primitive-load #$(activation-script gexps)))

(define (activation-profile-entry gexps)
  "Return, as a monadic value, an entry for the activation script in the
system directory."
  (mlet %store-monad ((activate (lower-object (activation-script gexps))))
    (return `(("activate" ,activate)))))

(define (second-argument a b) b)

(define activation-service-type
  (service-type (name 'activate)
                (extensions
                 (list (service-extension boot-service-type
                                          gexps->activation-gexp)
                       (service-extension system-service-type
                                          activation-profile-entry)))
                (compose identity)
                (extend second-argument)
                (default-value #f)
                (description
                 "Run @dfn{activation} code at boot time and upon
@command{guix system reconfigure} completion.")))

(define %activation-service
  ;; The activation service produces the activation script from the gexps it
  ;; receives.
  (service activation-service-type #t))

(define %modprobe-wrapper
  ;; Wrapper for the 'modprobe' command that knows where modules live.
  ;;
  ;; This wrapper is typically invoked by the Linux kernel ('call_modprobe',
  ;; in kernel/kmod.c), a situation where the 'LINUX_MODULE_DIRECTORY'
  ;; environment variable is not set---hence the need for this wrapper.
  (let ((modprobe "/run/current-system/profile/bin/modprobe"))
    (program-file "modprobe"
                  #~(begin
                      (setenv "LINUX_MODULE_DIRECTORY"
                              "/run/booted-system/kernel/lib/modules")
                      ;; FIXME: Remove this crutch when the patch #40422,
                      ;; updating to kmod 27 is merged.
                      (setenv "MODPROBE_OPTIONS"
                              "-C /etc/modprobe.d")
                      (apply execl #$modprobe
                             (cons #$modprobe (cdr (command-line))))))))

(define %linux-kernel-activation
  ;; Activation of the Linux kernel running on the bare metal (as opposed to
  ;; running in a container.)
  #~(begin
      ;; Tell the kernel to use our 'modprobe' command.
      (activate-modprobe #$%modprobe-wrapper)

      ;; Let users debug their own processes!
      (activate-ptrace-attach)))

(define %linux-bare-metal-service
  ;; The service that does things that are needed on the "bare metal", but not
  ;; necessary or impossible in a container.
  (simple-service 'linux-bare-metal
                  activation-service-type
                  %linux-kernel-activation))

(define %hurd-rc-script
  ;; The RC script to be started upon boot.
  (program-file "rc"
                (with-imported-modules (source-module-closure
                                        '((guix build utils)
                                          (gnu build hurd-boot)
                                          (guix build syscalls)))
                  #~(begin
                      (use-modules (guix build utils)
                                   (gnu build hurd-boot)
                                   (guix build syscalls)
                                   (ice-9 match)
                                   (system repl repl)
                                   (srfi srfi-1)
                                   (srfi srfi-26))
                      (boot-hurd-system)))))

(define (hurd-rc-entry rc)
  "Return, as a monadic value, an entry for the RC script in the system
directory."
  (mlet %store-monad ((rc (lower-object rc)))
    (return `(("rc" ,rc)))))

(define hurd-startup-service-type
  ;; The service that creates the initial SYSTEM/rc startup file.
  (service-type (name 'startup)
                (extensions
                 (list (service-extension system-service-type hurd-rc-entry)))
                (default-value %hurd-rc-script)
                (description "This service creates an @file{rc} script in the
system; that script is responsible for booting the Hurd.")))

(define %hurd-startup-service
  ;; The service that produces the RC script.
  (service hurd-startup-service-type %hurd-rc-script))

(define special-files-service-type
  ;; Service to install "special files" such as /bin/sh and /usr/bin/env.
  (service-type
   (name 'special-files)
   (extensions
    (list (service-extension activation-service-type
                             (lambda (files)
                               #~(activate-special-files '#$files)))))
   (compose concatenate)
   (extend append)
   (description
    "Add special files to the root file system---e.g.,
@file{/usr/bin/env}.")))

(define (extra-special-file file target)
  "Use TARGET as the \"special file\" FILE.  For example, TARGET might be
  (file-append coreutils \"/bin/env\")
and FILE could be \"/usr/bin/env\"."
  (simple-service (string->symbol (string-append "special-file-" file))
                  special-files-service-type
                  `((,file ,target))))

(define (etc-directory service)
  "Return the directory for SERVICE, a service of type ETC-SERVICE-TYPE."
  (files->etc-directory (service-value service)))

(define (files->etc-directory files)
  (define (assert-no-duplicates files)
    (let loop ((files files)
               (seen (set)))
      (match files
        (() #t)
        (((file _) rest ...)
         (when (set-contains? seen file)
           (raise (formatted-message (G_ "duplicate '~a' entry for /etc")
                                     file)))
         (loop rest (set-insert file seen))))))

  ;; Detect duplicates early instead of letting them through, eventually
  ;; leading to a build failure of "etc.drv".
  (assert-no-duplicates files)

  (file-union "etc" files))

(define (etc-entry files)
  "Return an entry for the /etc directory consisting of FILES in the system
directory."
  (with-monad %store-monad
    (return `(("etc" ,(files->etc-directory files))))))

(define etc-service-type
  (service-type (name 'etc)
                (extensions
                 (list
                  (service-extension activation-service-type
                                     (lambda (files)
                                       (let ((etc
                                              (files->etc-directory files)))
                                         #~(activate-etc #$etc))))
                  (service-extension system-service-type etc-entry)))
                (compose concatenate)
                (extend append)
                (default-value '())
                (description "Populate the @file{/etc} directory.")))

(define-deprecated (etc-service files)
  etc-service-type
  "Return a new service of ETC-SERVICE-TYPE that populates /etc with FILES.
FILES must be a list of name/file-like object pairs."
  (service etc-service-type files))

(define (privileged-program->activation-gexp programs)
  "Return an activation gexp for privileged-program from PROGRAMS."
  (let ((programs
         (map (lambda (program)
                ;; FIXME This is really ugly, I didn't manage to use "inherit".
                (let ((program-name (privileged-program-program program))
                      (setuid?      (privileged-program-setuid? program))
                      (setgid?      (privileged-program-setgid? program))
                      (user         (privileged-program-user program))
                      (group        (privileged-program-group program))
                      (capabilities (privileged-program-capabilities program)))
                  (unless (or setuid? setgid? capabilities)
                    (warning
                     (G_ "so-called privileged-program ~s lacks any privilege~%")
                     program-name))
                  #~(privileged-program (setuid? #$setuid?)
                                        (setgid? #$setgid?)
                                        (user    #$user)
                                        (group   #$group)
                                        (capabilities #$capabilities)
                                        (program #$program-name))))
              programs)))
    (with-imported-modules (source-module-closure
                            '((gnu system privilege)))
      #~(begin
          (use-modules (gnu system privilege))

          (let ((libcap #$(let-system (system target)
                            ;; When cross-compiling, assume libcap is
                            ;; available on GNU/Linux only.
                            (and (if target
                                     (string-suffix? "linux-gnu" target)
                                     (supported-package? libcap system))
                                 libcap))))
            (activate-privileged-programs (list #$@programs) libcap))))))

(define privileged-program-service-type
  (service-type (name 'privileged-program)
                (extensions
                 (list (service-extension activation-service-type
                                          privileged-program->activation-gexp)))
                (compose concatenate)
                (extend (lambda (config extensions)
                          (append config extensions)))
                (description
                 "Copy the specified executables to @file{/run/privileged/bin}
and apply special privileges like setuid and/or setgid.

The deprecated @file{/run/setuid-programs} directory is also populated with
symbolic links to their @file{/run/privileged/bin} counterpart.  It will be
removed in a future Guix release.")))

(define-deprecated/alias setuid-program-service-type
  ;; Deprecated alias to ease transition.  Will be removed!
  privileged-program-service-type)

(define (packages->profile-entry packages)
  "Return a system entry for the profile containing PACKAGES."
  ;; XXX: 'mlet' is needed here for one reason: to get the proper
  ;; '%current-target' and '%current-target-system' bindings when
  ;; 'packages->manifest' is called, and thus when the 'package-inputs'
  ;; etc. procedures are called on PACKAGES.  That way, conditionals in those
  ;; inputs see the "correct" value of these two parameters.  See
  ;; <https://issues.guix.gnu.org/44952>.
  (mlet %store-monad ((_ (current-target-system)))
    (return `(("profile" ,(profile
                           (content (packages->manifest
                                     (delete-duplicates packages eq?)))))))))

(define profile-service-type
  ;; The service that populates the system's profile---i.e.,
  ;; /run/current-system/profile.  It is extended by package lists.
  (service-type (name 'profile)
                (extensions
                 (list (service-extension system-service-type
                                          packages->profile-entry)))
                (compose concatenate)
                (extend append)
                (default-value '())
                (description
                 "This is the @dfn{system profile}, available as
@file{/run/current-system/profile}.  It contains packages that the sysadmin
wants to be globally available to all the system users.")))

(define (firmware->activation-gexp firmware)
  "Return a gexp to make the packages listed in FIRMWARE loadable by the
kernel."
  (let ((directory (directory-union "firmware" firmware)))
    ;; Tell the kernel where firmware is.
    #~(activate-firmware (string-append #$directory "/lib/firmware"))))

(define firmware-service-type
  ;; The service that collects firmware.
  (service-type (name 'firmware)
                (extensions
                 (list (service-extension activation-service-type
                                          firmware->activation-gexp)))
                (compose concatenate)
                (extend append)
                (description
                 "Make ``firmware'' files loadable by the operating system
kernel.  Firmware may then be uploaded to some of the machine's devices, such
as Wifi cards.")))

(define (gc-roots->system-entry roots)
  "Return an entry in the system's output containing symlinks to ROOTS."
  (mlet %store-monad ((entry (gexp->derivation
                              "gc-roots"
                              #~(let ((roots '#$roots))
                                  (mkdir #$output)
                                  (chdir #$output)
                                  (for-each symlink
                                            roots
                                            (map number->string
                                                 (iota (length roots))))))))
    (return (if (null? roots)
                '()
                `(("gc-roots" ,entry))))))

(define gc-root-service-type
  ;; A service to associate extra garbage-collector roots to the system.  This
  ;; is a simple hack that guarantees that the system retains references to
  ;; the given list of roots.  Roots must be "lowerable" objects like
  ;; packages, or derivations.
  (service-type (name 'gc-roots)
                (extensions
                 (list (service-extension system-service-type
                                          gc-roots->system-entry)))
                (compose concatenate)
                (extend append)
                (description
                 "Register garbage-collector roots---i.e., store items that
will not be reclaimed by the garbage collector.")
                (default-value '())))

;; Configuration for the Linux kernel builder.
(define-record-type* <linux-builder-configuration>
  linux-builder-configuration
  make-linux-builder-configuration
  linux-builder-configuration?
  this-linux-builder-configuration

  (kernel   linux-builder-configuration-kernel)                   ; package
  (modules  linux-builder-configuration-modules  (default '())))  ; list of packages

(define (package-for-kernel target-kernel module-package)
  "Return a package like MODULE-PACKAGE, adapted for TARGET-KERNEL, if
possible (that is if there's a LINUX keyword argument in the build system)."
  (package
    (inherit module-package)
    (arguments
     (substitute-keyword-arguments (package-arguments module-package)
       ((#:linux kernel #f)
        target-kernel)))))

(define (linux-builder-configuration->system-entry config)
  "Return the kernel entry of the 'system' directory."
  (let* ((kernel  (linux-builder-configuration-kernel config))
         (modules (linux-builder-configuration-modules config))
         (kernel  (profile
                    (content (packages->manifest
                              (cons kernel
                                    (map (lambda (module)
                                           (cond
                                             ((package? module)
                                              (package-for-kernel kernel module))
                                             ;; support (,package "kernel-module-output")
                                             ((and (list? module) (package? (car module)))
                                              (cons (package-for-kernel kernel
                                                                        (car module))
                                                    (cdr module)))
                                             (else
                                              module)))
                                         modules))))
                    (hooks (list linux-module-database)))))
    (with-monad %store-monad
      (return `(("kernel" ,kernel))))))

(define linux-builder-service-type
  (service-type (name 'linux-builder)
                (extensions
                  (list (service-extension system-service-type
                                           linux-builder-configuration->system-entry)))
                (default-value '())
                (compose identity)
                (extend (lambda (config modifiers)
                          (if (null? modifiers)
                              config
                              ((apply compose modifiers) config))))
                (description "Builds the linux-libre kernel profile, containing
the kernel itself and any linux-loadable kernel modules.  This can be extended
with a function that accepts the current configuration and returns a new
configuration.")))

(define (linux-loadable-module-builder-modifier modules)
  "Extends linux-builder-service-type by appending the given MODULES to the
configuration of linux-builder-service-type."
  (lambda (config)
    (linux-builder-configuration
      (inherit config)
      (modules (append (linux-builder-configuration-modules config)
                       modules)))))

(define linux-loadable-module-service-type
  (service-type (name 'linux-loadable-modules)
                (extensions
                  (list (service-extension linux-builder-service-type
                                           linux-loadable-module-builder-modifier)))
                (default-value '())
                (compose concatenate)
                (extend append)
                (description "Adds packages and package outputs as modules
included in the booted linux-libre profile.  Other services can extend this
service type to add particular modules to the set of linux-loadable modules.")))


\f
;;;
;;; Service folding.
;;;

(define-condition-type &missing-target-service-error &service-error
  missing-target-service-error?
  (service      missing-target-service-error-service)
  (target-type  missing-target-service-error-target-type))

(define-condition-type &ambiguous-target-service-error &service-error
  ambiguous-target-service-error?
  (service      ambiguous-target-service-error-service)
  (target-type  ambiguous-target-service-error-target-type))

(define (missing-target-error service target-type)
  (raise
   (condition (&missing-target-service-error
               (service service)
               (target-type target-type))
              (&message
               (message
                (format #f (G_ "no target of type '~a' for service '~a'")
                        (service-type-name target-type)
                        (service-type-name
                         (service-kind service))))))))

(define (service-back-edges services)
  "Return a procedure that, when passed a <service>, returns the list of
<service> objects that depend on it."
  (define (add-edges service edges)
    (define (add-edge extension edges)
      (let ((target-type (service-extension-target extension)))
        (match (filter (lambda (service)
                         (eq? (service-kind service) target-type))
                       services)
          ((target)
           (vhash-consq target service edges))
          (()
           (missing-target-error service target-type))
          (x
           (raise
            (condition (&ambiguous-target-service-error
                        (service service)
                        (target-type target-type))
                       (&message
                        (message
                         (format #f
                                 (G_ "more than one target service of type '~a'")
                                 (service-type-name target-type))))))))))

    (fold add-edge edges (service-type-extensions (service-kind service))))

  (let ((edges (fold add-edges vlist-null services)))
    (lambda (node)
      (reverse (vhash-foldq* cons '() node edges)))))

(define (instantiate-missing-services services)
  "Return SERVICES, a list, augmented with any services targeted by extensions
and missing from SERVICES.  Only service types with a default value can be
instantiated; other missing services lead to a
'&missing-target-service-error'."
  (define (adjust-service-list svc result instances)
    (fold2 (lambda (extension result instances)
             (define target-type
               (service-extension-target extension))

             (match (vhash-assq target-type instances)
               (#f
                (let ((default (service-type-default-value target-type)))
                  (if (eq? &no-default-value default)
                      (missing-target-error svc target-type)
                      (let ((new (service target-type)))
                        (values (cons new result)
                                (vhash-consq target-type new instances))))))
               (_
                (values result instances))))
           result
           instances
           (service-type-extensions (service-kind svc))))

  (let loop ((services services))
    (define instances
      (fold (lambda (service result)
              (vhash-consq (service-kind service) service
                           result))
            vlist-null services))

    (define adjusted
      (fold2 adjust-service-list
             services instances
             services))

    ;; If we instantiated services, they might in turn depend on missing
    ;; services.  Loop until we've reached fixed point.
    (if (= (length adjusted) (vlist-length instances))
        adjusted
        (loop adjusted))))

(define* (fold-services services
                        #:key (target-type system-service-type))
  "Fold SERVICES by propagating their extensions down to the root of type
TARGET-TYPE; return the root service adjusted accordingly."
  (define dependents
    (service-back-edges services))

  (define (matching-extension target)
    (let ((target (service-kind target)))
      (match-lambda
        (($ <service-extension> type)
         (eq? type target)))))

  (define (apply-extension target)
    (lambda (service)
      (match (find (matching-extension target)
                   (service-type-extensions (service-kind service)))
        (($ <service-extension> _ compute)
         (compute (service-value service))))))

  (match (filter (lambda (service)
                   (eq? (service-kind service) target-type))
                 services)
    ((sink)
     ;; Use the state monad to keep track of already-visited services in the
     ;; graph and to memoize their value once folded.
     (run-with-state
         (let loop ((sink sink))
           (mlet %state-monad ((visited (current-state)))
             (match (vhash-assq sink visited)
               (#f
                (mlet* %state-monad
                    ((dependents (mapm %state-monad loop (dependents sink)))
                     (visited    (current-state))
                     (extensions -> (map (apply-extension sink) dependents))
                     (extend     -> (service-type-extend (service-kind sink)))
                     (compose    -> (service-type-compose (service-kind sink)))
                     (params     -> (service-value sink))
                     (service
                      ->
                      ;; Distinguish COMPOSE and EXTEND because PARAMS typically
                      ;; has a different type than the elements of EXTENSIONS.
                      (if extend
                          (service (service-kind sink)
                                   (extend params (compose extensions)))
                          sink)))
                  (mbegin %state-monad
                    (set-current-state (vhash-consq sink service visited))
                    (return service))))
               ((_ . service)                     ;SINK was already visited
                (return service)))))
       vlist-null))
    (()
     (raise
      (make-compound-condition
       (condition (&missing-target-service-error
                   (service #f)
                   (target-type target-type)))
       (formatted-message (G_ "service of type '~a' not found")
                          (service-type-name target-type)))))
    (x
     (raise
      (condition (&ambiguous-target-service-error
                  (service #f)
                  (target-type target-type))
                 (&message
                  (message
                   (format #f
                           (G_ "more than one target service of type '~a'")
                           (service-type-name target-type)))))))))

(define (remove-service-extensions type lst)
  "Return TYPE, a service type, without any of the service extensions
targeting one of the types in LST."
  (service-type
   (inherit type)
   (extensions (remove (lambda (extension)
                         (memq (service-extension-target extension) lst))
                       (service-type-extensions type)))))

(define-syntax-parameter for-home?
  ;; Whether the configuration being defined is for a Home service.
  (identifier-syntax #f))

(define-syntax-rule (for-home exp ...)
  "Mark EXP, which typically defines a service configuration, as targeting a
Home service rather than a System service."
  (syntax-parameterize ((for-home? (identifier-syntax #t)))
    exp ...))

(define-with-syntax-properties (validate-service-list (value properties))
  (%validate-service-list value properties))

(define (%validate-service-list value properties)
  (match value
    (((? service?) ...) value)
    (_
     (raise
      (make-compound-condition
       (condition
        (&error-location
         (location (source-properties->location properties))))
       (formatted-message
        (G_ "'services' field must contain a list of services")))))))

;;; services.scm ends here.

debug log:

solving 8a4002e072 ...
found 8a4002e072 in https://git.savannah.gnu.org/cgit/guix.git

(*) Git path names are given by the tree(s) the blob belongs to.
    Blobs themselves have no identifier aside from the hash of its contents.^

Code repositories for project(s) associated with this public inbox

	https://git.savannah.gnu.org/cgit/guix.git

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).