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
|
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2016, 2017, 2018, 2020 Ludovic Courtès <ludo@gnu.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 perform-download)
#:use-module (guix ui)
#:use-module (guix scripts)
#:use-module (guix derivations)
#:use-module ((guix store) #:select (derivation-path? store-path?))
#:use-module (guix build download)
#:use-module (ice-9 match)
#:export (guix-perform-download))
;; This program is a helper for the daemon's 'download' built-in builder.
(define-syntax derivation-let
(syntax-rules ()
((_ drv ((id name) rest ...) body ...)
(let ((id (assoc-ref (derivation-builder-environment-vars drv)
name)))
(derivation-let drv (rest ...) body ...)))
((_ drv () body ...)
(begin body ...))))
(define %user-module
;; Module in which content-address mirror procedures are evaluated.
(let ((module (make-fresh-user-module)))
(module-use! module (resolve-interface '(guix base32)))
module))
(define* (perform-download drv output
#:key print-build-trace?)
"Perform the download described by DRV, a fixed-output derivation, to
OUTPUT.
Note: OUTPUT may differ from the 'out' value of DRV, notably for 'bmCheck' or
'bmRepair' builds."
(derivation-let drv ((url "url")
(executable "executable")
(mirrors "mirrors")
(content-addressed-mirrors "content-addressed-mirrors")
(disarchive-mirrors "disarchive-mirrors"))
(unless url
(leave (G_ "~a: missing URL~%") (derivation-file-name drv)))
(let* ((url (call-with-input-string url read))
(drv-output (assoc-ref (derivation-outputs drv) "out"))
(algo (derivation-output-hash-algo drv-output))
(hash (derivation-output-hash drv-output)))
(unless (and algo hash)
(leave (G_ "~a is not a fixed-output derivation~%")
(derivation-file-name drv)))
;; We're invoked by the daemon, which gives us write access to OUTPUT.
(when (url-fetch url output
#:print-build-trace? print-build-trace?
#:mirrors (if mirrors
(call-with-input-file mirrors read)
'())
#:content-addressed-mirrors
(if content-addressed-mirrors
(call-with-input-file content-addressed-mirrors
(lambda (port)
(eval (read port) %user-module)))
'())
#:disarchive-mirrors
(if disarchive-mirrors
(call-with-input-file disarchive-mirrors read)
'())
#:hashes `((,algo . ,hash))
;; Since DRV's output hash is known, X.509 certificate
;; validation is pointless.
#:verify-certificate? #f)
(when (and executable (string=? executable "1"))
(chmod output #o755))))))
(define (assert-low-privileges)
(when (zero? (getuid))
(leave (G_ "refusing to run with elevated privileges (UID ~a)~%")
(getuid))))
(define-command (guix-perform-download . args)
(category internal)
(synopsis "perform download described by fixed-output derivations")
;; This is an "out-of-band" download in that this code is executed directly
;; by the daemon and not explicitly described as an input of the derivation.
;; This allows us to sidestep bootstrapping problems, such as downloading
;; the source code of GnuTLS over HTTPS before we have built GnuTLS. See
;; <https://bugs.gnu.org/22774>.
(define print-build-trace?
(match (getenv "_NIX_OPTIONS")
(#f #f)
(str (string-contains str "print-extended-build-trace=1"))))
;; This program must be invoked by guix-daemon under an unprivileged UID to
;; prevent things downloading from 'file:///etc/shadow' or arbitrary code
;; execution via the content-addressed mirror procedures. (That means we
;; exclude users who did not pass '--build-users-group'.)
(with-error-handling
(match args
(((? derivation-path? drv) (? store-path? output))
(assert-low-privileges)
(let ((drv (read-derivation-from-file drv)))
(perform-download drv output #:print-build-trace? print-build-trace?)))
(("--version")
(show-version-and-exit))
(x
(leave
(G_ "fixed-output derivation and output file name expected~%"))))))
;; Local Variables:
;; eval: (put 'derivation-let 'scheme-indent-function 2)
;; End:
;; perform-download.scm ends here
|
