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