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Diffstat (limited to 'gnu/system/uuid.scm')
| -rw-r--r-- | gnu/system/uuid.scm | 283 |
1 files changed, 283 insertions, 0 deletions
diff --git a/gnu/system/uuid.scm b/gnu/system/uuid.scm new file mode 100644 index 0000000000..6470abb8cc --- /dev/null +++ b/gnu/system/uuid.scm @@ -0,0 +1,283 @@ +;;; GNU Guix --- Functional package management for GNU +;;; Copyright © 2016, 2017 Ludovic Courtès <ludo@gnu.org> +;;; Copyright © 2017 Danny Milosavljevic <dannym@scratchpost.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 (gnu system uuid) + #:use-module (srfi srfi-1) + #:use-module (srfi srfi-9) + #:use-module (rnrs bytevectors) + #:use-module (ice-9 match) + #:use-module (ice-9 vlist) + #:use-module (ice-9 regex) + #:use-module (ice-9 format) + #:export (uuid + uuid? + uuid-type + uuid-bytevector + + bytevector->uuid + + uuid->string + dce-uuid->string + string->uuid + string->dce-uuid + string->iso9660-uuid + string->ext2-uuid + string->ext3-uuid + string->ext4-uuid + string->btrfs-uuid + string->fat32-uuid + iso9660-uuid->string + + ;; XXX: For lack of a better place. + sub-bytevector + latin1->string)) + + +;;; +;;; Tools that lack a better place. +;;; + +(define (sub-bytevector bv start size) + "Return a copy of the SIZE bytes of BV starting from offset START." + (let ((result (make-bytevector size))) + (bytevector-copy! bv start result 0 size) + result)) + +(define (latin1->string bv terminator) + "Return a string of BV, a latin1 bytevector, or #f. TERMINATOR is a predicate +that takes a number and returns #t when a termination character is found." + (let ((bytes (take-while (negate terminator) (bytevector->u8-list bv)))) + (if (null? bytes) + #f + (list->string (map integer->char bytes))))) + + +;;; +;;; DCE UUIDs. +;;; + +(define-syntax %network-byte-order + (identifier-syntax (endianness big))) + +(define (dce-uuid->string uuid) + "Convert UUID, a 16-byte bytevector, to its string representation, something +like \"6b700d61-5550-48a1-874c-a3d86998990e\"." + ;; See <https://tools.ietf.org/html/rfc4122>. + (let ((time-low (bytevector-uint-ref uuid 0 %network-byte-order 4)) + (time-mid (bytevector-uint-ref uuid 4 %network-byte-order 2)) + (time-hi (bytevector-uint-ref uuid 6 %network-byte-order 2)) + (clock-seq (bytevector-uint-ref uuid 8 %network-byte-order 2)) + (node (bytevector-uint-ref uuid 10 %network-byte-order 6))) + (format #f "~8,'0x-~4,'0x-~4,'0x-~4,'0x-~12,'0x" + time-low time-mid time-hi clock-seq node))) + +(define %uuid-rx + ;; The regexp of a UUID. + (make-regexp "^([[:xdigit:]]{8})-([[:xdigit:]]{4})-([[:xdigit:]]{4})-([[:xdigit:]]{4})-([[:xdigit:]]{12})$")) + +(define (string->dce-uuid str) + "Parse STR as a DCE UUID (see <https://tools.ietf.org/html/rfc4122>) and +return its contents as a 16-byte bytevector. Return #f if STR is not a valid +UUID representation." + (and=> (regexp-exec %uuid-rx str) + (lambda (match) + (letrec-syntax ((hex->number + (syntax-rules () + ((_ index) + (string->number (match:substring match index) + 16)))) + (put! + (syntax-rules () + ((_ bv index (number len) rest ...) + (begin + (bytevector-uint-set! bv index number + (endianness big) len) + (put! bv (+ index len) rest ...))) + ((_ bv index) + bv)))) + (let ((time-low (hex->number 1)) + (time-mid (hex->number 2)) + (time-hi (hex->number 3)) + (clock-seq (hex->number 4)) + (node (hex->number 5)) + (uuid (make-bytevector 16))) + (put! uuid 0 + (time-low 4) (time-mid 2) (time-hi 2) + (clock-seq 2) (node 6))))))) + + +;;; +;;; ISO-9660. +;;; + +;; <http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-119.pdf>. + +(define %iso9660-uuid-rx + ;; Y m d H M S ss + (make-regexp "^([[:digit:]]{4})-([[:digit:]]{2})-([[:digit:]]{2})-([[:digit:]]{2})-([[:digit:]]{2})-([[:digit:]]{2})-([[:digit:]]{2})$")) +(define (string->iso9660-uuid str) + "Parse STR as a ISO9660 UUID (which is really a timestamp - see /dev/disk/by-uuid). +Return its contents as a 16-byte bytevector. Return #f if STR is not a valid +ISO9660 UUID representation." + (and=> (regexp-exec %iso9660-uuid-rx str) + (lambda (match) + (letrec-syntax ((match-numerals + (syntax-rules () + ((_ index (name rest ...) body) + (let ((name (match:substring match index))) + (match-numerals (+ 1 index) (rest ...) body))) + ((_ index () body) + body)))) + (match-numerals 1 (year month day hour minute second hundredths) + (string->utf8 (string-append year month day + hour minute second hundredths))))))) +(define (iso9660-uuid->string uuid) + "Given an UUID bytevector, return its timestamp string." + (define (digits->string bytes) + (latin1->string bytes (lambda (c) #f))) + (let* ((year (sub-bytevector uuid 0 4)) + (month (sub-bytevector uuid 4 2)) + (day (sub-bytevector uuid 6 2)) + (hour (sub-bytevector uuid 8 2)) + (minute (sub-bytevector uuid 10 2)) + (second (sub-bytevector uuid 12 2)) + (hundredths (sub-bytevector uuid 14 2)) + (parts (list year month day hour minute second hundredths))) + (string-append (string-join (map digits->string parts) "-")))) + + +;;; +;;; FAT32. +;;; + +(define-syntax %fat32-endianness + ;; Endianness of FAT file systems. + (identifier-syntax (endianness little))) + +(define (fat32-uuid->string uuid) + "Convert fat32 UUID, a 4-byte bytevector, to its string representation." + (let ((high (bytevector-uint-ref uuid 0 %fat32-endianness 2)) + (low (bytevector-uint-ref uuid 2 %fat32-endianness 2))) + (format #f "~:@(~x-~x~)" low high))) + +(define %fat32-uuid-rx + (make-regexp "^([[:xdigit:]]{4})-([[:xdigit:]]{4})$")) + +(define (string->fat32-uuid str) + "Parse STR, which is in FAT32 format, and return a bytevector or #f." + (match (regexp-exec %fat32-uuid-rx str) + (#f + #f) + (rx-match + (uint-list->bytevector (list (string->number + (match:substring rx-match 2) 16) + (string->number + (match:substring rx-match 1) 16)) + %fat32-endianness + 2)))) + + +;;; +;;; Generic interface. +;;; + +(define string->ext2-uuid string->dce-uuid) +(define string->ext3-uuid string->dce-uuid) +(define string->ext4-uuid string->dce-uuid) +(define string->btrfs-uuid string->dce-uuid) + +(define-syntax vhashq + (syntax-rules (=>) + ((_) + vlist-null) + ((_ (key others ... => value) rest ...) + (vhash-consq key value + (vhashq (others ... => value) rest ...))) + ((_ (=> value) rest ...) + (vhashq rest ...)))) + +(define %uuid-parsers + (vhashq + ('dce 'ext2 'ext3 'ext4 'btrfs 'luks => string->dce-uuid) + ('fat32 'fat => string->fat32-uuid) + ('iso9660 => string->iso9660-uuid))) + +(define %uuid-printers + (vhashq + ('dce 'ext2 'ext3 'ext4 'btrfs 'luks => dce-uuid->string) + ('iso9660 => iso9660-uuid->string) + ('fat32 'fat => fat32-uuid->string))) + +(define* (string->uuid str #:optional (type 'dce)) + "Parse STR as a UUID of the given TYPE. On success, return the +corresponding bytevector; otherwise return #f." + (match (vhash-assq type %uuid-parsers) + (#f #f) + ((_ . (? procedure? parse)) (parse str)))) + +;; High-level UUID representation that carries its type with it. +;; +;; This is necessary to serialize bytevectors with the right printer in some +;; circumstances. For instance, GRUB "search --fs-uuid" command compares the +;; string representation of UUIDs, not the raw bytes; thus, when emitting a +;; GRUB 'search' command, we need to procedure the right string representation +;; (see <https://debbugs.gnu.org/cgi/bugreport.cgi?msg=52;att=0;bug=27735>). +(define-record-type <uuid> + (make-uuid type bv) + uuid? + (type uuid-type) ;'dce | 'iso9660 | ... + (bv uuid-bytevector)) + +(define* (bytevector->uuid bv #:optional (type 'dce)) + "Return a UUID object make of BV and TYPE." + (make-uuid type bv)) + +(define-syntax uuid + (lambda (s) + "Return the UUID object corresponding to the given UUID representation." + (syntax-case s (quote) + ((_ str (quote type)) + (and (string? (syntax->datum #'str)) + (identifier? #'type)) + ;; A literal string: do the conversion at expansion time. + (let ((bv (string->uuid (syntax->datum #'str) + (syntax->datum #'type)))) + (unless bv + (syntax-violation 'uuid "invalid UUID" s)) + #`(make-uuid 'type #,(datum->syntax s bv)))) + ((_ str) + (string? (syntax->datum #'str)) + #'(uuid str 'dce)) + ((_ str) + #'(make-uuid 'dce (string->uuid str 'dce))) + ((_ str type) + #'(make-uuid type (string->uuid str type)))))) + +(define uuid->string + ;; Convert the given bytevector or UUID object, to the corresponding UUID + ;; string representation. + (match-lambda* + (((? bytevector? bv)) + (uuid->string bv 'dce)) + (((? bytevector? bv) type) + (match (vhash-assq type %uuid-printers) + (#f #f) + ((_ . (? procedure? unparse)) (unparse bv)))) + (((? uuid? uuid)) + (uuid->string (uuid-bytevector uuid) (uuid-type uuid))))) |