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-rw-r--r--guix/build/kconfig.scm183
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+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2020 Stefan <stefan-guix@vodafonemail.de>
+;;;
+;;; 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 build kconfig)
+ #:use-module (ice-9 rdelim)
+ #:use-module (ice-9 regex)
+ #:use-module (srfi srfi-1)
+ #:use-module (srfi srfi-26)
+ #:export (modify-defconfig
+ verify-config))
+
+;; Commentary:
+;;
+;; Builder-side code to modify configurations for the Kconfig build system as
+;; used by Linux and U-Boot.
+;;
+;; Code:
+
+(define (config-string->pair config-string)
+ "Parse a configuration string like \"CONFIG_EXAMPLE=m\" into a key-value pair.
+An error is thrown for invalid configurations.
+
+\"CONFIG_A=y\" -> '(\"CONFIG_A\" . \"y\")
+\"CONFIG_B=\\\"\\\"\" -> '(\"CONFIG_B\" . \"\\\"\\\"\")
+\"CONFIG_C=\" -> '(\"CONFIG_C\" . \"\")
+\"# CONFIG_E is not set\" -> '(\"CONFIG_E\" . #f)
+\"CONFIG_D\" -> '(\"CONFIG_D\" . #f)
+\"# Any comment\" -> '(#f . \"# Any comment\")
+\"\" -> '(#f . \"\")
+\"# CONFIG_E=y\" -> (error \"Invalid configuration\")
+\"CONFIG_E is not set\" -> (error \"Invalid configuration\")
+\"Anything else\" -> (error \"Invalid configuration\")"
+ (define config-regexp
+ (make-regexp
+ ;; (match:substring (string-match "=(.*)" "=") 1) returns "", but the
+ ;; pattern "=(.+)?" makes it return #f instead. From a "CONFIG_A=" we like
+ ;; to get "", which later emits "CONFIG_A=" again.
+ (string-append "^ *(#[\\t ]*)?(CONFIG_[a-zA-Z0-9_]+)([\\t ]*="
+ "[\\t ]*(.*)|([\\t ]+is[\\t ]+not[\\t ]+set))?$")))
+
+ (define config-comment-regexp
+ (make-regexp "^([\\t ]*(#.*)?)$"))
+
+ (let ((match (regexp-exec config-regexp (string-trim-right config-string))))
+ (if match
+ (let* ((comment (match:substring match 1))
+ (key (match:substring match 2))
+ (unset (match:substring match 5))
+ (value (and (not comment)
+ (not unset)
+ (match:substring match 4))))
+ (if (eq? (not comment) (not unset))
+ ;; The key is uncommented and set or commented and unset.
+ (cons key value)
+ ;; The key is set or unset ambigiously.
+ (error (format #f "invalid configuration, did you mean \"~a\"?"
+ (pair->config-string (cons key #f)))
+ config-string)))
+ ;; This is not a valid or ambigious config-string, but maybe a
+ ;; comment.
+ (if (regexp-exec config-comment-regexp config-string)
+ (cons #f config-string) ;keep valid comments
+ (error "Invalid configuration" config-string)))))
+
+(define (pair->config-string pair)
+ "Convert a PAIR back to a config-string."
+ (let* ((key (first pair))
+ (value (cdr pair)))
+ (if (string? key)
+ (if (string? value)
+ (string-append key "=" value)
+ (string-append "# " key " is not set"))
+ value)))
+
+(define (defconfig->alist defconfig)
+ "Convert the content of a DEFCONFIG (or .config) file into an alist."
+ (with-input-from-file defconfig
+ (lambda ()
+ (let loop ((alist '())
+ (line (read-line)))
+ (if (eof-object? line)
+ ;; Building the alist is done, now check for duplicates.
+ ;; Note: the filter invocation is used to remove comments.
+ (let loop ((keys (map first (filter first alist)))
+ (duplicates '()))
+ (if (null? keys)
+ ;; The search for duplicates is done.
+ ;; Return the alist or throw an error on duplicates.
+ (if (null? duplicates)
+ alist
+ (error
+ (format #f "duplicate configurations in ~a" defconfig)
+ duplicates))
+ ;; Continue the search for duplicates.
+ (loop (cdr keys)
+ (if (member (first keys) (cdr keys))
+ (cons (first keys) duplicates)
+ duplicates))))
+ ;; Build the alist.
+ (loop (cons (config-string->pair line) alist)
+ (read-line)))))))
+
+(define (modify-defconfig defconfig configs)
+ "This function can modify a given DEFCONFIG (or .config) file by adding,
+changing or removing the list of strings in CONFIGS. This allows customization
+of Kconfig based projects like the kernel Linux or the bootloader 'Das U-Boot'.
+
+These are examples for CONFIGS to add, change or remove configurations to/from
+DEFCONFIG:
+
+'(\"CONFIG_A=\\\"a\\\"\"
+ \"CONFIG_B=0\"
+ \"CONFIG_C=y\"
+ \"CONFIG_D=m\"
+ \"CONFIG_E=\"
+ \"# CONFIG_G is not set\"
+ ;; For convenience this abbrevation can be used for not set configurations.
+ \"CONFIG_F\")
+
+Instead of a list, CONFIGS can be a string with one configuration per line."
+ (let* (;; Split the configs into a list of single configurations. Both a
+ ;; string and or a list of strings is supported, each with newlines
+ ;; to separate configurations.
+ (config-pairs (map config-string->pair
+ (append-map (cut string-split <> #\newline)
+ (if (string? configs)
+ (list configs)
+ configs))))
+ ;; Generate a blocklist from all valid keys in config-pairs.
+ (blocklist (delete #f (map first config-pairs)))
+ ;; Generate an alist from the defconfig without the keys in blocklist.
+ (filtered-defconfig-pairs (remove (lambda (pair)
+ (member (first pair) blocklist))
+ (defconfig->alist defconfig))))
+ (with-output-to-file defconfig
+ (lambda ()
+ (for-each (lambda (pair)
+ (display (pair->config-string pair))
+ (newline))
+ (append filtered-defconfig-pairs config-pairs))))))
+
+(define (verify-config config defconfig)
+ "Verify that the CONFIG file contains all configurations from the DEFCONFIG
+file. When the verification fails, raise an error with the mismatching keys
+and their values."
+ (let* ((config-pairs (defconfig->alist config))
+ (defconfig-pairs (defconfig->alist defconfig))
+ (mismatching-pairs
+ (remove (lambda (pair)
+ ;; Remove all configurations, whose values are #f and
+ ;; whose keys are not in config-pairs, as not in
+ ;; config-pairs means unset, ...
+ (and (not (cdr pair))
+ (not (assoc-ref config-pairs (first pair)))))
+ ;; ... from the defconfig-pairs different to config-pairs.
+ (lset-difference equal?
+ ;; Remove comments by filtering with first.
+ (filter first defconfig-pairs)
+ config-pairs))))
+ (unless (null? mismatching-pairs)
+ (error (format #f "Mismatching configurations in ~a and ~a"
+ config defconfig)
+ (map (lambda (mismatching-pair)
+ (let* ((key (first mismatching-pair))
+ (defconfig-value (cdr mismatching-pair))
+ (config-value (assoc-ref config-pairs key)))
+ (cons key (list (list config-value defconfig-value)))))
+ mismatching-pairs)))))
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