;;; GNU Guix --- Functional package management for GNU ;;; Copyright © 2012, 2013, 2014, 2015, 2016 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 hash) #:use-module (guix gcrypt) #:use-module (rnrs bytevectors) #:use-module (ice-9 binary-ports) #:use-module (system foreign) #:use-module ((guix build utils) #:select (dump-port)) #:use-module (srfi srfi-11) #:export (sha256 open-sha256-port port-sha256 file-sha256 open-sha256-input-port)) ;;; Commentary: ;;; ;;; Cryptographic hashes. ;;; ;;; Code: ;;; ;;; Hash. ;;; (define-syntax GCRY_MD_SHA256 ;; Value as of Libgcrypt 1.5.2. (identifier-syntax 8)) (define sha256 (let ((hash (pointer->procedure void (libgcrypt-func "gcry_md_hash_buffer") `(,int * * ,size_t)))) (lambda (bv) "Return the SHA256 of BV as a bytevector." (let ((digest (make-bytevector (/ 256 8)))) (hash GCRY_MD_SHA256 (bytevector->pointer digest) (bytevector->pointer bv) (bytevector-length bv)) digest)))) (define open-sha256-md (let ((open (pointer->procedure int (libgcrypt-func "gcry_md_open") `(* ,int ,unsigned-int)))) (lambda () (let* ((md (bytevector->pointer (make-bytevector (sizeof '*)))) (err (open md GCRY_MD_SHA256 0))) (if (zero? err) (dereference-pointer md) (throw 'gcrypt-error err)))))) (define md-write (pointer->procedure void (libgcrypt-func "gcry_md_write") `(* * ,size_t))) (define md-read (pointer->procedure '* (libgcrypt-func "gcry_md_read") `(* ,int))) (define md-close (pointer->procedure void (libgcrypt-func "gcry_md_close") '(*))) (define (open-sha256-port) "Return two values: an output port, and a thunk. When the thunk is called, it returns the SHA256 hash (a bytevector) of all the data written to the output port." (define sha256-md (open-sha256-md)) (define digest #f) (define (finalize!) (let ((ptr (md-read sha256-md 0))) (set! digest (bytevector-copy (pointer->bytevector ptr 32))) (md-close sha256-md))) (define (write! bv offset len) (if (zero? len) (begin (finalize!) 0) (let ((ptr (bytevector->pointer bv offset))) (md-write sha256-md ptr len) len))) (define (close) (unless digest (finalize!))) (values (make-custom-binary-output-port "sha256" write! #f #f close) (lambda () (unless digest (finalize!)) digest))) (define (port-sha256 port) "Return the SHA256 hash (a bytevector) of all the data drained from PORT." (let-values (((out get) (open-sha256-port))) (dump-port port out) (close-port out) (get))) (define (file-sha256 file) "Return the SHA256 hash (a bytevector) of FILE." (call-with-input-file file port-sha256)) (define (open-sha256-input-port port) "Return an input port that wraps PORT and a thunk to get the hash of all the data read from PORT. The thunk always returns the same value." (define md (open-sha256-md)) (define (read! bv start count) (let ((n (get-bytevector-n! port bv start count))) (if (eof-object? n) 0 (begin (unless digest (let ((ptr (bytevector->pointer bv start))) (md-write md ptr n))) n)))) (define digest #f) (define (finalize!) (let ((ptr (md-read md 0))) (set! digest (bytevector-copy (pointer->bytevector ptr 32))) (md-close md))) (define (get-hash) (unless digest (finalize!)) digest) (define (unbuffered port) ;; Guile <= 2.0.9 does not support 'setvbuf' on custom binary input ports. ;; If you get a wrong-type-arg error here, the fix is to upgrade Guile. :-) (setvbuf port _IONBF) port) (values (unbuffered (make-custom-binary-input-port "sha256" read! #f #f #f)) get-hash)) ;;; hash.scm ends here