From 064c367716f88b7662b6b8e0d9dbd5eab941c25f Mon Sep 17 00:00:00 2001 From: Sarah Morgensen Date: Wed, 5 Jan 2022 14:07:47 +0000 Subject: [PATCH] guix hash: Extract file hashing procedures. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit * guix/scripts/hash.scm (guix-hash)[vcs-file?] (nar-hash, default-hash): Extract hashing logic to... * guix/hash.scm (vcs-file?, file-hash*): ... these new procedures in this new file. Modified-by: Maxime Devos Signed-off-by: Ludovic Courtès --- Makefile.am | 1 + guix/hash.scm | 73 +++++++++++++++++++++++++++++++++++++++++++ guix/scripts/hash.scm | 22 +++---------- 3 files changed, 78 insertions(+), 18 deletions(-) create mode 100644 guix/hash.scm diff --git a/Makefile.am b/Makefile.am index 3f06ef8991..d6aabac261 100644 --- a/Makefile.am +++ b/Makefile.am @@ -100,6 +100,7 @@ MODULES = \ guix/extracting-download.scm \ guix/git-download.scm \ guix/hg-download.scm \ + guix/hash.scm \ guix/swh.scm \ guix/monads.scm \ guix/monad-repl.scm \ diff --git a/guix/hash.scm b/guix/hash.scm new file mode 100644 index 0000000000..3cb68e5c44 --- /dev/null +++ b/guix/hash.scm @@ -0,0 +1,73 @@ +;;; GNU Guix --- Functional package management for GNU +;;; Copyright © 2021 Sarah Morgensen +;;; Copyright © 2022 Maxime Devos +;;; +;;; 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 . + +(define-module (guix hash) + #:use-module (gcrypt hash) + #:use-module (guix serialization) + #:use-module (srfi srfi-1) + #:use-module (srfi srfi-11) + #:export (vcs-file? + file-hash*)) + +(define (vcs-file? file stat) + "Returns true if FILE is a version control system file." + (case (stat:type stat) + ((directory) + (member (basename file) '(".bzr" ".git" ".hg" ".svn" "CVS"))) + ((regular) + ;; Git sub-modules have a '.git' file that is a regular text file. + (string=? (basename file) ".git")) + (else + #f))) + +(define* (file-hash* file #:key + (algorithm (hash-algorithm sha256)) + (recursive? 'auto) + (select? (negate vcs-file?))) + "Compute the hash of FILE with ALGORITHM. + +Symbolic links are only dereferenced if RECURSIVE? is false. +Directories are only supported if RECURSIVE? is #true or 'auto'. +The executable bit is only recorded if RECURSIVE? is #true. +If FILE is a symbolic link, it is only followed if RECURSIVE? is false. + +For regular files, there are two different hashes when the executable +hash isn't recorded: the regular hash and the nar hash. In most situations, +the regular hash is desired and setting RECURSIVE? to 'auto' does the right +thing for both regular files and directories. + +This procedure must only be used under controlled circumstances; +the detection of symbolic links in FILE is racy. + +When FILE is a directory, the procedure SELECT? called as (SELECT? FILE STAT) +decides which files to include. By default, version control files are +excluded. To include everything, SELECT? can be set to (const #true)." + (if (or (eq? recursive? #true) + (and (eq? recursive? 'auto) + ;; Don't change this to (eq? 'directory ...), because otherwise + ;; if 'file' denotes a symbolic link, the 'file-hash' below + ;; would dereference it -- dereferencing symbolic links would + ;; open an avoidable can of potential worms. + (not (eq? 'regular (stat:type (lstat file)))))) + (let-values (((port get-hash) + (open-hash-port algorithm))) + (write-file file port #:select? select?) + (force-output port) + (get-hash)) + (file-hash algorithm file))) diff --git a/guix/scripts/hash.scm b/guix/scripts/hash.scm index c44a4de9a4..9715dc7779 100644 --- a/guix/scripts/hash.scm +++ b/guix/scripts/hash.scm @@ -4,6 +4,7 @@ ;;; Copyright © 2016 Jan Nieuwenhuizen ;;; Copyright © 2018 Tim Gesthuizen ;;; Copyright © 2021 Simon Tournier +;;; Copyright © 2021 Sarah Morgensen ;;; ;;; This file is part of GNU Guix. ;;; @@ -24,6 +25,7 @@ (define-module (guix scripts hash) #:use-module (gcrypt hash) #:use-module (guix serialization) #:use-module (guix ui) + #:use-module (guix hash) #:use-module (guix scripts) #:use-module (guix base16) #:use-module (guix base32) @@ -46,20 +48,14 @@ (define-module (guix scripts hash) (define* (nar-hash file #:optional (algorithm (assoc-ref %default-options 'hash-algorithm)) select?) - (let-values (((port get-hash) - (open-hash-port algorithm))) - (write-file file port #:select? select?) - (force-output port) - (get-hash))) + (file-hash* file #:algorithm algorithm #:select? select? #:recursive? #true)) (define* (default-hash file #:optional (algorithm (assoc-ref %default-options 'hash-algorithm)) select?) (match file ("-" (port-hash algorithm (current-input-port))) - (_ - (call-with-input-file file - (cute port-hash algorithm <>))))) + (_ (file-hash* file #:algorithm algorithm #:recursive? #false)))) (define* (git-hash file #:optional (algorithm (assoc-ref %default-options 'hash-algorithm)) @@ -181,16 +177,6 @@ (define (parse-options) (parse-command-line args %options (list %default-options) #:build-options? #f)) - (define (vcs-file? file stat) - (case (stat:type stat) - ((directory) - (member (basename file) '(".bzr" ".git" ".hg" ".svn" "CVS"))) - ((regular) - ;; Git sub-modules have a '.git' file that is a regular text file. - (string=? (basename file) ".git")) - (else - #f))) - (let* ((opts (parse-options)) (args (filter-map (match-lambda (('argument . value)