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
|
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2013, 2014, 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2014 Nikita Karetnikov <nikita@karetnikov.org>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
(define-module (guix scripts substitute)
#:use-module (guix ui)
#:use-module ((guix store) #:hide (close-connection))
#:use-module (guix utils)
#:use-module (guix combinators)
#:use-module (guix config)
#:use-module (guix records)
#:use-module ((guix serialization) #:select (restore-file))
#:use-module (guix hash)
#:use-module (guix base32)
#:use-module (guix base64)
#:use-module (guix cache)
#:use-module (guix pk-crypto)
#:use-module (guix pki)
#:use-module ((guix build utils) #:select (mkdir-p dump-port))
#:use-module ((guix build download)
#:select (current-terminal-columns
progress-proc uri-abbreviation nar-uri-abbreviation
(open-connection-for-uri
. guix:open-connection-for-uri)
close-connection
store-path-abbreviation byte-count->string))
#:use-module ((guix build syscalls)
#:select (set-thread-name))
#:use-module (ice-9 rdelim)
#:use-module (ice-9 regex)
#:use-module (ice-9 match)
#:use-module (ice-9 format)
#:use-module (ice-9 ftw)
#:use-module (ice-9 binary-ports)
#:use-module (ice-9 vlist)
#:use-module (rnrs bytevectors)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-9)
#:use-module (srfi srfi-11)
#:use-module (srfi srfi-19)
#:use-module (srfi srfi-26)
#:use-module (srfi srfi-34)
#:use-module (srfi srfi-35)
#:use-module (web uri)
#:use-module (web http)
#:use-module (web request)
#:use-module (web response)
#:use-module (guix http-client)
#:export (narinfo-signature->canonical-sexp
narinfo?
narinfo-path
narinfo-uri
narinfo-uri-base
narinfo-compression
narinfo-file-hash
narinfo-file-size
narinfo-hash
narinfo-size
narinfo-references
narinfo-deriver
narinfo-system
narinfo-signature
narinfo-hash->sha256
lookup-narinfos
lookup-narinfos/diverse
read-narinfo
write-narinfo
substitute-urls
guix-substitute))
;;; Comment:
;;;
;;; This is the "binary substituter". It is invoked by the daemon do check
;;; for the existence of available "substitutes" (pre-built binaries), and to
;;; actually use them as a substitute to building things locally.
;;;
;;; If possible, substitute a binary for the requested store path, using a Nix
;;; "binary cache". This program implements the Nix "substituter" protocol.
;;;
;;; Code:
(cond-expand
(guile-2.2
;; Guile 2.2.2 has a bug whereby 'time-monotonic' objects have seconds and
;; nanoseconds swapped (fixed in Guile commit 886ac3e). Work around it.
(define time-monotonic time-tai))
(else #t))
(define %narinfo-cache-directory
;; A local cache of narinfos, to avoid going to the network. Most of the
;; time, 'guix substitute' is called by guix-daemon as root and stores its
;; cached data in /var/guix/…. However, when invoked from 'guix challenge'
;; as a user, it stores its cache in ~/.cache.
(if (zero? (getuid))
(or (and=> (getenv "XDG_CACHE_HOME")
(cut string-append <> "/guix/substitute"))
(string-append %state-directory "/substitute/cache"))
(string-append (cache-directory #:ensure? #f) "/substitute")))
(define %allow-unauthenticated-substitutes?
;; Whether to allow unchecked substitutes. This is useful for testing
;; purposes, and should be avoided otherwise.
(and (and=> (getenv "GUIX_ALLOW_UNAUTHENTICATED_SUBSTITUTES")
(cut string-ci=? <> "yes"))
(begin
(warning (G_ "authentication and authorization of substitutes \
disabled!~%"))
#t)))
(define %narinfo-ttl
;; Number of seconds during which cached narinfo lookups are considered
;; valid for substitute servers that do not advertise a TTL via the
;; 'Cache-Control' response header.
(* 36 3600))
(define %narinfo-negative-ttl
;; Likewise, but for negative lookups---i.e., cached lookup failures (404).
(* 3 3600))
(define %narinfo-transient-error-ttl
;; Likewise, but for transient errors such as 504 ("Gateway timeout").
(* 10 60))
(define %narinfo-expired-cache-entry-removal-delay
;; How often we want to remove files corresponding to expired cache entries.
(* 7 24 3600))
(define fields->alist
;; The narinfo format is really just like recutils.
recutils->alist)
(define %fetch-timeout
;; Number of seconds after which networking is considered "slow".
5)
(define %random-state
(seed->random-state (+ (ash (cdr (gettimeofday)) 32) (getpid))))
(define-syntax-rule (with-timeout duration handler body ...)
"Run BODY; when DURATION seconds have expired, call HANDLER, and run BODY
again."
(begin
(sigaction SIGALRM
(lambda (signum)
(sigaction SIGALRM SIG_DFL)
handler))
(alarm duration)
(call-with-values
(lambda ()
(let try ()
(catch 'system-error
(lambda ()
body ...)
(lambda args
;; Before Guile v2.0.9-39-gfe51c7b, the SIGALRM triggers EINTR
;; because of the bug at
;; <http://lists.gnu.org/archive/html/guile-devel/2013-06/msg00050.html>.
;; When that happens, try again. Note: SA_RESTART cannot be
;; used because of <http://bugs.gnu.org/14640>.
(if (= EINTR (system-error-errno args))
(begin
;; Wait a little to avoid bursts.
(usleep (random 3000000 %random-state))
(try))
(apply throw args))))))
(lambda result
(alarm 0)
(sigaction SIGALRM SIG_DFL)
(apply values result)))))
(define* (fetch uri #:key (buffered? #t) (timeout? #t))
"Return a binary input port to URI and the number of bytes it's expected to
provide."
(case (uri-scheme uri)
((file)
(let ((port (open-file (uri-path uri)
(if buffered? "rb" "r0b"))))
(values port (stat:size (stat port)))))
((http https)
(guard (c ((http-get-error? c)
(leave (G_ "download from '~a' failed: ~a, ~s~%")
(uri->string (http-get-error-uri c))
(http-get-error-code c)
(http-get-error-reason c))))
;; Test this with:
;; sudo tc qdisc add dev eth0 root netem delay 1500ms
;; and then cancel with:
;; sudo tc qdisc del dev eth0 root
(let ((port #f))
(with-timeout (if timeout?
%fetch-timeout
0)
(begin
(warning (G_ "while fetching ~a: server is somewhat slow~%")
(uri->string uri))
(warning (G_ "try `--no-substitutes' if the problem persists~%"))
;; Before Guile v2.0.9-39-gfe51c7b, EINTR was reported to the user,
;; and thus PORT had to be closed and re-opened. This is not the
;; case afterward.
(unless (or (guile-version>? "2.0.9")
(version>? (version) "2.0.9.39"))
(when port
(close-connection port))))
(begin
(when (or (not port) (port-closed? port))
(set! port (guix:open-connection-for-uri
uri #:verify-certificate? #f))
(unless (or buffered? (not (file-port? port)))
(setvbuf port _IONBF)))
(http-fetch uri #:text? #f #:port port
#:verify-certificate? #f))))))
(else
(leave (G_ "unsupported substitute URI scheme: ~a~%")
(uri->string uri)))))
(define-record-type <cache-info>
(%make-cache-info url store-directory wants-mass-query?)
cache-info?
(url cache-info-url)
(store-directory cache-info-store-directory)
(wants-mass-query? cache-info-wants-mass-query?))
(define (download-cache-info url)
"Download the information for the cache at URL. On success, return a
<cache-info> object and a port on which to send further HTTP requests. On
failure, return #f and #f."
(define uri
(string->uri (string-append url "/nix-cache-info")))
(define (read-cache-info port)
(alist->record (fields->alist port)
(cut %make-cache-info url <...>)
'("StoreDir" "WantMassQuery")))
(catch #t
(lambda ()
(case (uri-scheme uri)
((file)
(values (call-with-input-file (uri-path uri)
read-cache-info)
#f))
((http https)
(let ((port (guix:open-connection-for-uri
uri
#:verify-certificate? #f
#:timeout %fetch-timeout)))
(guard (c ((http-get-error? c)
(warning (G_ "while fetching '~a': ~a (~s)~%")
(uri->string (http-get-error-uri c))
(http-get-error-code c)
(http-get-error-reason c))
(close-connection port)
(warning (G_ "ignoring substitute server at '~s'~%") url)
(values #f #f)))
(values (read-cache-info (http-fetch uri
#:verify-certificate? #f
#:port port
#:keep-alive? #t))
port))))))
(lambda (key . args)
(case key
((getaddrinfo-error system-error)
;; Silently ignore the error: probably due to lack of network access.
(values #f #f))
(else
(apply throw key args))))))
(define-record-type <narinfo>
(%make-narinfo path uri uri-base compression file-hash file-size nar-hash nar-size
references deriver system signature contents)
narinfo?
(path narinfo-path)
(uri narinfo-uri)
(uri-base narinfo-uri-base) ; URI of the cache it originates from
(compression narinfo-compression)
(file-hash narinfo-file-hash)
(file-size narinfo-file-size)
(nar-hash narinfo-hash)
(nar-size narinfo-size)
(references narinfo-references)
(deriver narinfo-deriver)
(system narinfo-system)
(signature narinfo-signature) ; canonical sexp
;; The original contents of a narinfo file. This field is needed because we
;; want to preserve the exact textual representation for verification purposes.
;; See <https://lists.gnu.org/archive/html/guix-devel/2014-02/msg00340.html>
;; for more information.
(contents narinfo-contents))
(define (narinfo-hash->sha256 hash)
"If the string HASH denotes a sha256 hash, return it as a bytevector.
Otherwise return #f."
(and (string-prefix? "sha256:" hash)
(nix-base32-string->bytevector (string-drop hash 7))))
(define (narinfo-signature->canonical-sexp str)
"Return the value of a narinfo's 'Signature' field as a canonical sexp."
(match (string-split str #\;)
((version host-name sig)
(let ((maybe-number (string->number version)))
(cond ((not (number? maybe-number))
(leave (G_ "signature version must be a number: ~s~%")
version))
;; Currently, there are no other versions.
((not (= 1 maybe-number))
(leave (G_ "unsupported signature version: ~a~%")
maybe-number))
(else
(let ((signature (utf8->string (base64-decode sig))))
(catch 'gcry-error
(lambda ()
(string->canonical-sexp signature))
(lambda (key proc err)
(leave (G_ "signature is not a valid \
s-expression: ~s~%")
signature))))))))
(x
(leave (G_ "invalid format of the signature field: ~a~%") x))))
(define (narinfo-maker str cache-url)
"Return a narinfo constructor for narinfos originating from CACHE-URL. STR
must contain the original contents of a narinfo file."
(lambda (path url compression file-hash file-size nar-hash nar-size
references deriver system signature)
"Return a new <narinfo> object."
(%make-narinfo path
;; Handle the case where URL is a relative URL.
(or (string->uri url)
(string->uri (string-append cache-url "/" url)))
cache-url
compression file-hash
(and=> file-size string->number)
nar-hash
(and=> nar-size string->number)
(string-tokenize references)
(match deriver
((or #f "") #f)
(_ deriver))
system
(false-if-exception
(and=> signature narinfo-signature->canonical-sexp))
str)))
(define* (assert-valid-signature narinfo signature hash
#:optional (acl (current-acl)))
"Bail out if SIGNATURE, a canonical sexp representing the signature of
NARINFO, doesn't match HASH, a bytevector containing the hash of NARINFO."
(let ((uri (uri->string (narinfo-uri narinfo))))
(signature-case (signature hash acl)
(valid-signature #t)
(invalid-signature
(leave (G_ "invalid signature for '~a'~%") uri))
(hash-mismatch
(leave (G_ "hash mismatch for '~a'~%") uri))
(unauthorized-key
(leave (G_ "'~a' is signed with an unauthorized key~%") uri))
(corrupt-signature
(leave (G_ "signature on '~a' is corrupt~%") uri)))))
(define* (read-narinfo port #:optional url
#:key size)
"Read a narinfo from PORT. If URL is true, it must be a string used to
build full URIs from relative URIs found while reading PORT. When SIZE is
true, read at most SIZE bytes from PORT; otherwise, read as much as possible.
No authentication and authorization checks are performed here!"
(let ((str (utf8->string (if size
(get-bytevector-n port size)
(get-bytevector-all port)))))
(alist->record (call-with-input-string str fields->alist)
(narinfo-maker str url)
'("StorePath" "URL" "Compression"
"FileHash" "FileSize" "NarHash" "NarSize"
"References" "Deriver" "System"
"Signature"))))
(define (narinfo-sha256 narinfo)
"Return the sha256 hash of NARINFO as a bytevector, or #f if NARINFO lacks a
'Signature' field."
(let ((contents (narinfo-contents narinfo)))
(match (string-contains contents "Signature:")
(#f #f)
(index
(let ((above-signature (string-take contents index)))
(sha256 (string->utf8 above-signature)))))))
(define* (valid-narinfo? narinfo #:optional (acl (current-acl))
#:key verbose?)
"Return #t if NARINFO's signature is not valid."
(or %allow-unauthenticated-substitutes?
(let ((hash (narinfo-sha256 narinfo))
(signature (narinfo-signature narinfo))
(uri (uri->string (narinfo-uri narinfo))))
(and hash signature
(signature-case (signature hash acl)
(valid-signature #t)
(invalid-signature
(when verbose?
(format (current-error-port)
"invalid signature for substitute at '~a'~%"
uri))
#f)
(hash-mismatch
(when verbose?
(format (current-error-port)
"hash mismatch for substitute at '~a'~%"
uri))
#f)
(unauthorized-key
(when verbose?
(format (current-error-port)
"substitute at '~a' is signed by an \
unauthorized party~%"
uri))
#f)
(corrupt-signature
(when verbose?
(format (current-error-port)
"corrupt signature for substitute at '~a'~%"
uri))
#f))))))
(define (write-narinfo narinfo port)
"Write NARINFO to PORT."
(put-bytevector port (string->utf8 (narinfo-contents narinfo))))
(define (narinfo->string narinfo)
"Return the external representation of NARINFO."
(call-with-output-string (cut write-narinfo narinfo <>)))
(define (string->narinfo str cache-uri)
"Return the narinfo represented by STR. Assume CACHE-URI as the base URI of
the cache STR originates form."
(call-with-input-string str (cut read-narinfo <> cache-uri)))
(define (narinfo-cache-file cache-url path)
"Return the name of the local file that contains an entry for PATH. The
entry is stored in a sub-directory specific to CACHE-URL."
;; The daemon does not sanitize its input, so PATH could be something like
;; "/gnu/store/foo". Gracefully handle that.
(match (store-path-hash-part path)
(#f
(leave (G_ "'~a' does not name a store item~%") path))
((? string? hash-part)
(string-append %narinfo-cache-directory "/"
(bytevector->base32-string (sha256 (string->utf8 cache-url)))
"/" hash-part))))
(define (cached-narinfo cache-url path)
"Check locally if we have valid info about PATH coming from CACHE-URL.
Return two values: a Boolean indicating whether we have valid cached info, and
that info, which may be either #f (when PATH is unavailable) or the narinfo
for PATH."
(define now
(current-time time-monotonic))
(define cache-file
(narinfo-cache-file cache-url path))
(catch 'system-error
(lambda ()
(call-with-input-file cache-file
(lambda (p)
(match (read p)
(('narinfo ('version 2)
('cache-uri cache-uri)
('date date) ('ttl ttl) ('value #f))
;; A cached negative lookup.
(if (obsolete? date now ttl)
(values #f #f)
(values #t #f)))
(('narinfo ('version 2)
('cache-uri cache-uri)
('date date) ('ttl ttl) ('value value))
;; A cached positive lookup
(if (obsolete? date now ttl)
(values #f #f)
(values #t (string->narinfo value cache-uri))))
(('narinfo ('version v) _ ...)
(values #f #f))))))
(lambda _
(values #f #f))))
(define (cache-narinfo! cache-url path narinfo ttl)
"Cache locally NARNIFO for PATH, which originates from CACHE-URL, with the
given TTL (a number of seconds or #f). NARINFO may be #f, in which case it
indicates that PATH is unavailable at CACHE-URL."
(define now
(current-time time-monotonic))
(define (cache-entry cache-uri narinfo)
`(narinfo (version 2)
(cache-uri ,cache-uri)
(date ,(time-second now))
(ttl ,(or ttl
(if narinfo %narinfo-ttl %narinfo-negative-ttl)))
(value ,(and=> narinfo narinfo->string))))
(let ((file (narinfo-cache-file cache-url path)))
(mkdir-p (dirname file))
(with-atomic-file-output file
(lambda (out)
(write (cache-entry cache-url narinfo) out))))
narinfo)
(define (narinfo-request cache-url path)
"Return an HTTP request for the narinfo of PATH at CACHE-URL."
(let ((url (string-append cache-url "/" (store-path-hash-part path)
".narinfo"))
(headers '((User-Agent . "GNU Guile"))))
(build-request (string->uri url) #:method 'GET #:headers headers)))
(define* (http-multiple-get base-uri proc seed requests
#:key port (verify-certificate? #t))
"Send all of REQUESTS to the server at BASE-URI. Call PROC for each
response, passing it the request object, the response, a port from which to
read the response body, and the previous result, starting with SEED, à la
'fold'. Return the final result. When PORT is specified, use it as the
initial connection on which HTTP requests are sent."
(let connect ((port port)
(requests requests)
(result seed))
;; (format (current-error-port) "connecting (~a requests left)..."
;; (length requests))
(let ((p (or port (guix:open-connection-for-uri
base-uri
#:verify-certificate?
verify-certificate?))))
;; For HTTPS, P is not a file port and does not support 'setvbuf'.
(when (file-port? p)
(setvbuf p _IOFBF (expt 2 16)))
;; Send all of REQUESTS in a row.
;; XXX: Do our own caching to work around inefficiencies when
;; communicating over TLS: <http://bugs.gnu.org/22966>.
(let-values (((buffer get) (open-bytevector-output-port)))
;; On Guile > 2.0.9, inherit the HTTP proxying property from P.
(when (module-variable (resolve-interface '(web http))
'http-proxy-port?)
(set-http-proxy-port?! buffer (http-proxy-port? p)))
(for-each (cut write-request <> buffer) requests)
(put-bytevector p (get))
(force-output p))
;; Now start processing responses.
(let loop ((requests requests)
(result result))
(match requests
(()
(reverse result))
((head tail ...)
(let* ((resp (read-response p))
(body (response-body-port resp))
(result (proc head resp body result)))
;; The server can choose to stop responding at any time, in which
;; case we have to try again. Check whether that is the case.
;; Note that even upon "Connection: close", we can read from BODY.
(match (assq 'connection (response-headers resp))
(('connection 'close)
(close-connection p)
(connect #f tail result)) ;try again
(_
(loop tail result)))))))))) ;keep going
(define (read-to-eof port)
"Read from PORT until EOF is reached. The data are discarded."
(dump-port port (%make-void-port "w")))
(define (narinfo-from-file file url)
"Attempt to read a narinfo from FILE, using URL as the cache URL. Return #f
if file doesn't exist, and the narinfo otherwise."
(catch 'system-error
(lambda ()
(call-with-input-file file
(cut read-narinfo <> url)))
(lambda args
(if (= ENOENT (system-error-errno args))
#f
(apply throw args)))))
(define (fetch-narinfos url paths)
"Retrieve all the narinfos for PATHS from the cache at URL and return them."
(define update-progress!
(let ((done 0)
(total (length paths)))
(lambda ()
(display #\cr (current-error-port))
(force-output (current-error-port))
(format (current-error-port)
(G_ "updating list of substitutes from '~a'... ~5,1f%")
url (* 100. (/ done total)))
(set! done (+ 1 done)))))
(define hash-part->path
(let ((mapping (fold (lambda (path result)
(vhash-cons (store-path-hash-part path) path
result))
vlist-null
paths)))
(lambda (hash)
(match (vhash-assoc hash mapping)
(#f #f)
((_ . path) path)))))
(define (handle-narinfo-response request response port result)
(let* ((code (response-code response))
(len (response-content-length response))
(cache (response-cache-control response))
(ttl (and cache (assoc-ref cache 'max-age))))
;; Make sure to read no more than LEN bytes since subsequent bytes may
;; belong to the next response.
(if (= code 200) ; hit
(let ((narinfo (read-narinfo port url #:size len)))
(cache-narinfo! url (narinfo-path narinfo) narinfo ttl)
(update-progress!)
(cons narinfo result))
(let* ((path (uri-path (request-uri request)))
(hash-part (basename
(string-drop-right path 8)))) ;drop ".narinfo"
(if len
(get-bytevector-n port len)
(read-to-eof port))
(cache-narinfo! url (hash-part->path hash-part) #f
(if (= 404 code)
ttl
%narinfo-transient-error-ttl))
(update-progress!)
result))))
(define (do-fetch uri port)
(case (and=> uri uri-scheme)
((http https)
(let ((requests (map (cut narinfo-request url <>) paths)))
(update-progress!)
;; Note: Do not check HTTPS server certificates to avoid depending on
;; the X.509 PKI. We can do it because we authenticate narinfos,
;; which provides a much stronger guarantee.
(let ((result (http-multiple-get uri
handle-narinfo-response '()
requests
#:verify-certificate? #f
#:port port)))
(close-connection port)
(newline (current-error-port))
result)))
((file #f)
(let* ((base (string-append (uri-path uri) "/"))
(files (map (compose (cut string-append base <> ".narinfo")
store-path-hash-part)
paths)))
(filter-map (cut narinfo-from-file <> url) files)))
(else
(leave (G_ "~s: unsupported server URI scheme~%")
(if uri (uri-scheme uri) url)))))
(let-values (((cache-info port)
(download-cache-info url)))
(and cache-info
(if (string=? (cache-info-store-directory cache-info)
(%store-prefix))
(do-fetch (string->uri url) port) ;reuse PORT
(begin
(warning (G_ "'~a' uses different store '~a'; ignoring it~%")
url (cache-info-store-directory cache-info))
(close-connection port)
#f)))))
(define (lookup-narinfos cache paths)
"Return the narinfos for PATHS, invoking the server at CACHE when no
information is available locally."
(let-values (((cached missing)
(fold2 (lambda (path cached missing)
(let-values (((valid? value)
(cached-narinfo cache path)))
(if valid?
(if value
(values (cons value cached) missing)
(values cached missing))
(values cached (cons path missing)))))
'()
'()
paths)))
(if (null? missing)
cached
(let ((missing (fetch-narinfos cache missing)))
(append cached (or missing '()))))))
(define (equivalent-narinfo? narinfo1 narinfo2)
"Return true if NARINFO1 and NARINFO2 are equivalent--i.e., if they describe
the same store item. This ignores unnecessary metadata such as the Nar URL."
(and (string=? (narinfo-hash narinfo1)
(narinfo-hash narinfo2))
;; The following is not needed if all we want is to download a valid
;; nar, but it's necessary if we want valid narinfo.
(string=? (narinfo-path narinfo1)
(narinfo-path narinfo2))
(equal? (narinfo-references narinfo1)
(narinfo-references narinfo2))
(= (narinfo-size narinfo1)
(narinfo-size narinfo2))))
(define (lookup-narinfos/diverse caches paths authorized?)
"Look up narinfos for PATHS on all of CACHES, a list of URLS, in that order.
That is, when a cache lacks an AUTHORIZED? narinfo, look it up in the next
cache, and so on.
Return a list of narinfos for PATHS or a subset thereof. The returned
narinfos are either AUTHORIZED?, or they claim a hash that matches an
AUTHORIZED? narinfo."
(define (select-hit result)
(lambda (path)
(match (vhash-fold* cons '() path result)
((one)
one)
((several ..1)
(let ((authorized (find authorized? (reverse several))))
(and authorized
(find (cut equivalent-narinfo? <> authorized)
several)))))))
(let loop ((caches caches)
(paths paths)
(result vlist-null) ;path->narinfo vhash
(hits '())) ;paths
(match paths
(() ;we're done
;; Now iterate on all the HITS, and return exactly one match for each
;; hit: the first narinfo that is authorized, or that has the same hash
;; as an authorized narinfo, in the order of CACHES.
(filter-map (select-hit result) hits))
(_
(match caches
((cache rest ...)
(let* ((narinfos (lookup-narinfos cache paths))
(definite (map narinfo-path (filter authorized? narinfos)))
(missing (lset-difference string=? paths definite))) ;XXX: perf
(loop rest missing
(fold vhash-cons result
(map narinfo-path narinfos) narinfos)
(append definite hits))))
(() ;that's it
(filter-map (select-hit result) hits)))))))
(define (lookup-narinfo caches path authorized?)
"Return the narinfo for PATH in CACHES, or #f when no substitute for PATH
was found."
(match (lookup-narinfos/diverse caches (list path) authorized?)
((answer) answer)
(_ #f)))
(define (cached-narinfo-expiration-time file)
"Return the expiration time for FILE, which is a cached narinfo."
(catch 'system-error
(lambda ()
(call-with-input-file file
(lambda (port)
(match (read port)
(('narinfo ('version 2) ('cache-uri uri)
('date date) ('ttl ttl) ('value #f))
(+ date ttl))
(('narinfo ('version 2) ('cache-uri uri)
('date date) ('ttl ttl) ('value value))
(+ date ttl))
(x
0)))))
(lambda args
;; FILE may have been deleted.
0)))
(define (narinfo-cache-directories directory)
"Return the list of narinfo cache directories (one per cache URL.)"
(map (cut string-append directory "/" <>)
(scandir %narinfo-cache-directory
(lambda (item)
(and (not (member item '("." "..")))
(file-is-directory?
(string-append %narinfo-cache-directory
"/" item)))))))
(define* (cached-narinfo-files #:optional
(directory %narinfo-cache-directory))
"Return the list of cached narinfo files under DIRECTORY."
(append-map (lambda (directory)
(map (cut string-append directory "/" <>)
(scandir directory
(lambda (file)
(= (string-length file) 32)))))
(narinfo-cache-directories directory)))
(define (progress-report-port report-progress port)
"Return a port that calls REPORT-PROGRESS every time something is read from
PORT. REPORT-PROGRESS is a two-argument procedure such as that returned by
`progress-proc'."
(define total 0)
(define (read! bv start count)
(let ((n (match (get-bytevector-n! port bv start count)
((? eof-object?) 0)
(x x))))
(set! total (+ total n))
(report-progress total (const n))
;; XXX: We're not in control, so we always return anyway.
n))
(make-custom-binary-input-port "progress-port-proc"
read! #f #f
(cut close-connection port)))
(define-syntax with-networking
(syntax-rules ()
"Catch DNS lookup errors and TLS errors and gracefully exit."
;; Note: no attempt is made to catch other networking errors, because DNS
;; lookup errors are typically the first one, and because other errors are
;; a subset of `system-error', which is harder to filter.
((_ exp ...)
(catch #t
(lambda () exp ...)
(match-lambda*
(('getaddrinfo-error error)
(leave (G_ "host name lookup error: ~a~%")
(gai-strerror error)))
(('gnutls-error error proc . rest)
(let ((error->string (module-ref (resolve-interface '(gnutls))
'error->string)))
(leave (G_ "TLS error in procedure '~a': ~a~%")
proc (error->string error))))
(args
(apply throw args)))))))
;;;
;;; Help.
;;;
(define (show-help)
(display (G_ "Usage: guix substitute [OPTION]...
Internal tool to substitute a pre-built binary to a local build.\n"))
(display (G_ "
--query report on the availability of substitutes for the
store file names passed on the standard input"))
(display (G_ "
--substitute STORE-FILE DESTINATION
download STORE-FILE and store it as a Nar in file
DESTINATION"))
(newline)
(display (G_ "
-h, --help display this help and exit"))
(display (G_ "
-V, --version display version information and exit"))
(newline)
(show-bug-report-information))
;;;
;;; Daemon/substituter protocol.
;;;
(define (display-narinfo-data narinfo)
"Write to the current output port the contents of NARINFO in the format
expected by the daemon."
(format #t "~a\n~a\n~a\n"
(narinfo-path narinfo)
(or (and=> (narinfo-deriver narinfo)
(cute string-append (%store-prefix) "/" <>))
"")
(length (narinfo-references narinfo)))
(for-each (cute format #t "~a/~a~%" (%store-prefix) <>)
(narinfo-references narinfo))
(format #t "~a\n~a\n"
(or (narinfo-file-size narinfo) 0)
(or (narinfo-size narinfo) 0)))
(define* (process-query command
#:key cache-urls acl)
"Reply to COMMAND, a query as written by the daemon to this process's
standard input. Use ACL as the access-control list against which to check
authorized substitutes."
(define (valid? obj)
(valid-narinfo? obj acl))
(match (string-tokenize command)
(("have" paths ..1)
;; Return the subset of PATHS available in CACHE-URLS.
(let ((substitutable (lookup-narinfos/diverse cache-urls paths valid?)))
(for-each (lambda (narinfo)
(format #t "~a~%" (narinfo-path narinfo)))
substitutable)
(newline)))
(("info" paths ..1)
;; Reply info about PATHS if it's in CACHE-URLS.
(let ((substitutable (lookup-narinfos/diverse cache-urls paths valid?)))
(for-each display-narinfo-data substitutable)
(newline)))
(wtf
(error "unknown `--query' command" wtf))))
(define* (process-substitution store-item destination
#:key cache-urls acl)
"Substitute STORE-ITEM (a store file name) from CACHE-URLS, and write it to
DESTINATION as a nar file. Verify the substitute against ACL."
(let* ((narinfo (lookup-narinfo cache-urls store-item
(cut valid-narinfo? <> acl)))
(uri (and=> narinfo narinfo-uri)))
(unless uri
(leave (G_ "no valid substitute for '~a'~%")
store-item))
;; Tell the daemon what the expected hash of the Nar itself is.
(format #t "~a~%" (narinfo-hash narinfo))
(format (current-error-port)
(G_ "Downloading ~a...~%") (uri->string uri))
(let*-values (((raw download-size)
;; Note that Hydra currently generates Nars on the fly
;; and doesn't specify a Content-Length, so
;; DOWNLOAD-SIZE is #f in practice.
(fetch uri #:buffered? #f #:timeout? #f))
((progress)
(let* ((comp (narinfo-compression narinfo))
(dl-size (or download-size
(and (equal? comp "none")
(narinfo-size narinfo))))
(progress (progress-proc (uri->string uri)
dl-size
(current-error-port)
#:abbreviation
nar-uri-abbreviation)))
(progress-report-port progress raw)))
((input pids)
(decompressed-port (and=> (narinfo-compression narinfo)
string->symbol)
progress)))
;; Unpack the Nar at INPUT into DESTINATION.
(restore-file input destination)
(close-port input)
;; Skip a line after what 'progress-proc' printed, and another one to
;; visually separate substitutions.
(display "\n\n" (current-error-port))
(every (compose zero? cdr waitpid) pids))))
;;;
;;; Entry point.
;;;
(define (check-acl-initialized)
"Warn if the ACL is uninitialized."
(define (singleton? acl)
;; True if ACL contains just the user's public key.
(and (file-exists? %public-key-file)
(let ((key (call-with-input-file %public-key-file
(compose string->canonical-sexp
read-string))))
(match acl
((thing)
(equal? (canonical-sexp->string thing)
(canonical-sexp->string key)))
(_
#f)))))
(let ((acl (acl->public-keys (current-acl))))
(when (or (null? acl) (singleton? acl))
(warning (G_ "ACL for archive imports seems to be uninitialized, \
substitutes may be unavailable\n")))))
(define (daemon-options)
"Return a list of name/value pairs denoting build daemon options."
(define %not-newline
(char-set-complement (char-set #\newline)))
(match (getenv "_NIX_OPTIONS")
(#f ;should not happen when called by the daemon
'())
(newline-separated
;; Here we get something of the form "OPTION1=VALUE1\nOPTION2=VALUE2\n".
(filter-map (lambda (option=value)
(match (string-index option=value #\=)
(#f ;invalid option setting
#f)
(equal-sign
(cons (string-take option=value equal-sign)
(string-drop option=value (+ 1 equal-sign))))))
(string-tokenize newline-separated %not-newline)))))
(define (find-daemon-option option)
"Return the value of build daemon option OPTION, or #f if it could not be
found."
(assoc-ref (daemon-options) option))
(define %default-substitute-urls
(match (and=> (or (find-daemon-option "untrusted-substitute-urls") ;client
(find-daemon-option "substitute-urls")) ;admin
string-tokenize)
((urls ...)
urls)
(#f
;; This can only happen when this script is not invoked by the
;; daemon.
'("http://hydra.gnu.org"))))
(define substitute-urls
;; List of substitute URLs.
(make-parameter %default-substitute-urls))
(define (client-terminal-columns)
"Return the number of columns in the client's terminal, if it is known, or a
default value."
(or (and=> (or (find-daemon-option "untrusted-terminal-columns")
(find-daemon-option "terminal-columns"))
(lambda (str)
(let ((number (string->number str)))
(and number (max 20 (- number 1))))))
80))
(define (validate-uri uri)
(unless (string->uri uri)
(leave (G_ "~a: invalid URI~%") uri)))
(define (guix-substitute . args)
"Implement the build daemon's substituter protocol."
(mkdir-p %narinfo-cache-directory)
(maybe-remove-expired-cache-entries %narinfo-cache-directory
cached-narinfo-files
#:entry-expiration
cached-narinfo-expiration-time
#:cleanup-period
%narinfo-expired-cache-entry-removal-delay)
(check-acl-initialized)
;; Starting from commit 22144afa in Nix, we are allowed to bail out directly
;; when we know we cannot substitute, but we must emit a newline on stdout
;; when everything is alright.
(when (null? (substitute-urls))
(exit 0))
;; Say hello (see above.)
(newline)
(force-output (current-output-port))
;; Sanity-check SUBSTITUTE-URLS so we can provide a meaningful error message.
(for-each validate-uri (substitute-urls))
;; Attempt to install the client's locale, mostly so that messages are
;; suitably translated.
(match (or (find-daemon-option "untrusted-locale")
(find-daemon-option "locale"))
(#f #f)
(locale (false-if-exception (setlocale LC_ALL locale))))
(set-thread-name "guix substitute")
(with-networking
(with-error-handling ; for signature errors
(match args
(("--query")
(let ((acl (current-acl)))
(let loop ((command (read-line)))
(or (eof-object? command)
(begin
(process-query command
#:cache-urls (substitute-urls)
#:acl acl)
(loop (read-line)))))))
(("--substitute" store-path destination)
;; Download STORE-PATH and add store it as a Nar in file DESTINATION.
;; Specify the number of columns of the terminal so the progress
;; report displays nicely.
(parameterize ((current-terminal-columns (client-terminal-columns)))
(process-substitution store-path destination
#:cache-urls (substitute-urls)
#:acl (current-acl))))
(("--version")
(show-version-and-exit "guix substitute"))
(("--help")
(show-help))
(opts
(leave (G_ "~a: unrecognized options~%") opts))))))
;;; Local Variables:
;;; eval: (put 'with-timeout 'scheme-indent-function 1)
;;; End:
;;; substitute.scm ends here
|