cf4e7083ed
A client closing the connection while reading from a /nar URL would leave an open file descriptor in the server. This patch fixes it. * guix/scripts/publish.scm (swallow-EPIPE): New macro. (http-write): Use it around 'write-file' call.
388 lines
14 KiB
Scheme
388 lines
14 KiB
Scheme
;;; GNU Guix --- Functional package management for GNU
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;;; Copyright © 2015 David Thompson <davet@gnu.org>
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;;; Copyright © 2015 Ludovic Courtès <ludo@gnu.org>
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;;;
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;;; This file is part of GNU Guix.
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;;;
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;;; GNU Guix is free software; you can redistribute it and/or modify it
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;;; under the terms of the GNU General Public License as published by
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;;; the Free Software Foundation; either version 3 of the License, or (at
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;;; your option) any later version.
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;;;
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;;; GNU Guix is distributed in the hope that it will be useful, but
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;;; WITHOUT ANY WARRANTY; without even the implied warranty of
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;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;;; GNU General Public License for more details.
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;;;
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;;; You should have received a copy of the GNU General Public License
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;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
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(define-module (guix scripts publish)
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#:use-module ((system repl server) #:prefix repl:)
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#:use-module (ice-9 binary-ports)
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#:use-module (ice-9 format)
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#:use-module (ice-9 match)
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#:use-module (ice-9 regex)
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#:use-module (rnrs io ports)
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#:use-module (rnrs bytevectors)
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#:use-module (srfi srfi-1)
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#:use-module (srfi srfi-2)
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#:use-module (srfi srfi-9 gnu)
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#:use-module (srfi srfi-26)
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#:use-module (srfi srfi-37)
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#:use-module (web http)
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#:use-module (web request)
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#:use-module (web response)
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#:use-module (web server)
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#:use-module (web uri)
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#:use-module (guix base32)
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#:use-module (guix base64)
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#:use-module (guix config)
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#:use-module (guix derivations)
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#:use-module (guix hash)
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#:use-module (guix pki)
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#:use-module (guix pk-crypto)
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#:use-module (guix store)
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#:use-module (guix serialization)
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#:use-module (guix ui)
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#:use-module (guix scripts)
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#:export (guix-publish))
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(define (show-help)
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(format #t (_ "Usage: guix publish [OPTION]...
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Publish ~a over HTTP.\n") %store-directory)
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(display (_ "
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-p, --port=PORT listen on PORT"))
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(display (_ "
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--listen=HOST listen on the network interface for HOST"))
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(display (_ "
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-u, --user=USER change privileges to USER as soon as possible"))
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(display (_ "
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-r, --repl[=PORT] spawn REPL server on PORT"))
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(newline)
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(display (_ "
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-h, --help display this help and exit"))
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(display (_ "
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-V, --version display version information and exit"))
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(newline)
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(show-bug-report-information))
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(define (getaddrinfo* host)
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"Like 'getaddrinfo', but properly report errors."
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(catch 'getaddrinfo-error
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(lambda ()
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(getaddrinfo host))
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(lambda (key error)
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(leave (_ "lookup of host '~a' failed: ~a~%")
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host (gai-strerror error)))))
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(define %options
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(list (option '(#\h "help") #f #f
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(lambda _
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(show-help)
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(exit 0)))
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(option '(#\V "version") #f #f
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(lambda _
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(show-version-and-exit "guix publish")))
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(option '(#\u "user") #t #f
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(lambda (opt name arg result)
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(alist-cons 'user arg result)))
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(option '(#\p "port") #t #f
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(lambda (opt name arg result)
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(alist-cons 'port (string->number* arg) result)))
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(option '("listen") #t #f
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(lambda (opt name arg result)
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(match (getaddrinfo* arg)
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((info _ ...)
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(alist-cons 'address (addrinfo:addr info)
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result))
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(()
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(leave (_ "lookup of host '~a' returned nothing")
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name)))))
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(option '(#\r "repl") #f #t
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(lambda (opt name arg result)
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;; If port unspecified, use default Guile REPL port.
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(let ((port (and arg (string->number* arg))))
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(alist-cons 'repl (or port 37146) result))))))
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(define %default-options
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`((port . 8080)
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(address . ,(make-socket-address AF_INET INADDR_ANY 0))
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(repl . #f)))
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(define (lazy-read-file-sexp file)
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"Return a promise to read the canonical sexp from FILE."
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(delay
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(call-with-input-file file
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(compose string->canonical-sexp
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get-string-all))))
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(define %private-key
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(lazy-read-file-sexp %private-key-file))
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(define %public-key
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(lazy-read-file-sexp %public-key-file))
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(define %nix-cache-info
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`(("StoreDir" . ,%store-directory)
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("WantMassQuery" . 0)
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("Priority" . 100)))
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(define (load-derivation file)
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"Read the derivation from FILE."
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(call-with-input-file file read-derivation))
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(define (signed-string s)
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"Sign the hash of the string S with the daemon's key."
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(let* ((public-key (force %public-key))
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(hash (bytevector->hash-data (sha256 (string->utf8 s))
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#:key-type (key-type public-key))))
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(signature-sexp hash (force %private-key) public-key)))
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(define base64-encode-string
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(compose base64-encode string->utf8))
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(define (narinfo-string store-path path-info key)
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"Generate a narinfo key/value string for STORE-PATH using the details in
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PATH-INFO. The narinfo is signed with KEY."
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(let* ((url (string-append "nar/" (basename store-path)))
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(hash (bytevector->nix-base32-string
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(path-info-hash path-info)))
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(size (path-info-nar-size path-info))
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(references (string-join
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(map basename (path-info-references path-info))
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" "))
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(deriver (path-info-deriver path-info))
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(base-info (format #f
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"StorePath: ~a
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URL: ~a
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Compression: none
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NarHash: sha256:~a
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NarSize: ~d
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References: ~a~%"
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store-path url hash size references))
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;; Do not render a "Deriver" or "System" line if we are rendering
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;; info for a derivation.
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(info (if (string-null? deriver)
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base-info
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(catch 'system-error
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(lambda ()
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(let ((drv (load-derivation deriver)))
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(format #f "~aSystem: ~a~%Deriver: ~a~%"
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base-info (derivation-system drv)
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(basename deriver))))
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(lambda args
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;; DERIVER might be missing, but that's fine:
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;; it's only used for <substitutable> where it's
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;; optional. 'System' is currently unused.
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(if (= ENOENT (system-error-errno args))
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base-info
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(apply throw args))))))
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(signature (base64-encode-string
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(canonical-sexp->string (signed-string info)))))
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(format #f "~aSignature: 1;~a;~a~%" info (gethostname) signature)))
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(define (not-found request)
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"Render 404 response for REQUEST."
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(values (build-response #:code 404)
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(string-append "Resource not found: "
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(uri-path (request-uri request)))))
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(define (render-nix-cache-info)
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"Render server information."
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(values '((content-type . (text/plain)))
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(lambda (port)
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(for-each (match-lambda
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((key . value)
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(format port "~a: ~a~%" key value)))
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%nix-cache-info))))
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(define (render-narinfo store request hash)
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"Render metadata for the store path corresponding to HASH."
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(let* ((store-path (hash-part->path store hash))
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(path-info (and (not (string-null? store-path))
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(query-path-info store store-path))))
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(if path-info
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(values '((content-type . (application/x-nix-narinfo)))
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(cut display
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(narinfo-string store-path path-info (force %private-key))
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<>))
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(not-found request))))
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(define (render-nar request store-item)
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"Render archive of the store path corresponding to STORE-ITEM."
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(let ((store-path (string-append %store-directory "/" store-item)))
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;; The ISO-8859-1 charset *must* be used otherwise HTTP clients will
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;; interpret the byte stream as UTF-8 and arbitrarily change invalid byte
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;; sequences.
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(if (file-exists? store-path)
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(values '((content-type . (application/x-nix-archive
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(charset . "ISO-8859-1"))))
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;; XXX: We're not returning the actual contents, deferring
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;; instead to 'http-write'. This is a hack to work around
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;; <http://bugs.gnu.org/21093>.
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store-path)
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(not-found request))))
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(define extract-narinfo-hash
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(let ((regexp (make-regexp "^([a-df-np-sv-z0-9]{32}).narinfo$")))
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(lambda (str)
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"Return the hash within the narinfo resource string STR, or false if STR
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is invalid."
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(and=> (regexp-exec regexp str)
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(cut match:substring <> 1)))))
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(define (get-request? request)
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"Return #t if REQUEST uses the GET method."
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(eq? (request-method request) 'GET))
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(define (request-path-components request)
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"Split the URI path of REQUEST into a list of component strings. For
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example: \"/foo/bar\" yields '(\"foo\" \"bar\")."
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(split-and-decode-uri-path (uri-path (request-uri request))))
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;;;
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;;; Server.
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;;;
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(define %http-write
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(@@ (web server http) http-write))
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(define (sans-content-length response)
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"Return RESPONSE without its 'content-length' header."
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(set-field response (response-headers)
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(alist-delete 'content-length
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(response-headers response)
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eq?)))
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(define-syntax-rule (swallow-EPIPE exp ...)
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"Swallow EPIPE errors raised by EXP..."
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(catch 'system-error
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(lambda ()
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exp ...)
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(lambda args
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(if (= EPIPE (system-error-errno args))
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(values)
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(apply throw args)))))
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(define (http-write server client response body)
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"Write RESPONSE and BODY to CLIENT, possibly in a separate thread to avoid
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blocking."
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(match (response-content-type response)
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(('application/x-nix-archive . _)
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;; Sending the the whole archive can take time so do it in a separate
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;; thread so that the main thread can keep working in the meantime.
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(call-with-new-thread
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(lambda ()
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(let* ((response (write-response (sans-content-length response)
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client))
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(port (response-port response)))
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;; XXX: Given our ugly workaround for <http://bugs.gnu.org/21093> in
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;; 'render-nar', BODY here is just the file name of the store item.
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;; We call 'write-file' from here because we know that's the only
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;; way to avoid building the whole nar in memory, which could
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;; quickly become a real problem. As a bonus, we even do
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;; sendfile(2) directly from the store files to the socket.
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(swallow-EPIPE
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(write-file (utf8->string body) port))
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(close-port port)
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(values)))))
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(_
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;; Handle other responses sequentially.
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(%http-write server client response body))))
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(define-server-impl concurrent-http-server
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;; A variant of Guile's built-in HTTP server that offloads possibly long
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;; responses to a different thread.
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(@@ (web server http) http-open)
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(@@ (web server http) http-read)
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http-write
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(@@ (web server http) http-close))
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(define (make-request-handler store)
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(lambda (request body)
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(format #t "~a ~a~%"
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(request-method request)
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(uri-path (request-uri request)))
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(if (get-request? request) ; reject POST, PUT, etc.
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(match (request-path-components request)
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;; /nix-cache-info
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(("nix-cache-info")
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(render-nix-cache-info))
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;; /<hash>.narinfo
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(((= extract-narinfo-hash (? string? hash)))
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(render-narinfo store request hash))
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;; /nar/<store-item>
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(("nar" store-item)
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(render-nar request store-item))
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(_ (not-found request)))
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(not-found request))))
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(define (run-publish-server socket store)
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(run-server (make-request-handler store)
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concurrent-http-server
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`(#:socket ,socket)))
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(define (open-server-socket address)
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"Return a TCP socket bound to ADDRESS, a socket address."
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(let ((sock (socket (sockaddr:fam address) SOCK_STREAM 0)))
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(setsockopt sock SOL_SOCKET SO_REUSEADDR 1)
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(bind sock address)
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sock))
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(define (gather-user-privileges user)
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"Switch to the identity of USER, a user name."
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(catch 'misc-error
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(lambda ()
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(let ((user (getpw user)))
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(setgroups #())
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(setgid (passwd:gid user))
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(setuid (passwd:uid user))))
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(lambda (key proc message args . rest)
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(leave (_ "user '~a' not found: ~a~%")
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user (apply format #f message args)))))
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;;;
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;;; Entry point.
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;;;
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(define (guix-publish . args)
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(with-error-handling
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(let* ((opts (args-fold* args %options
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(lambda (opt name arg result)
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(leave (_ "~A: unrecognized option~%") name))
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(lambda (arg result)
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(leave (_ "~A: extraneous argument~%") arg))
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%default-options))
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(user (assoc-ref opts 'user))
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(port (assoc-ref opts 'port))
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(address (let ((addr (assoc-ref opts 'address)))
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(make-socket-address (sockaddr:fam addr)
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(sockaddr:addr addr)
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port)))
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(socket (open-server-socket address))
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(repl-port (assoc-ref opts 'repl)))
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;; Read the key right away so that (1) we fail early on if we can't
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;; access them, and (2) we can then drop privileges.
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(force %private-key)
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(force %public-key)
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(when user
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;; Now that we've read the key material and opened the socket, we can
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;; drop privileges.
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(gather-user-privileges user))
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(when (zero? (getuid))
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(warning (_ "server running as root; \
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consider using the '--user' option!~%")))
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(format #t (_ "publishing ~a on ~a, port ~d~%")
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%store-directory
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(inet-ntop (sockaddr:fam address) (sockaddr:addr address))
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(sockaddr:port address))
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(when repl-port
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(repl:spawn-server (repl:make-tcp-server-socket #:port repl-port)))
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(with-store store
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(run-publish-server socket store)))))
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