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;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2014 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 (gnu build linux-modules)
#:use-module (guix elf)
#:use-module (rnrs io ports)
#:use-module (rnrs bytevectors)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-26)
#:use-module (ice-9 vlist)
#:use-module (ice-9 match)
#:export (dot-ko
ensure-dot-ko
module-dependencies
recursive-module-dependencies
modules-loaded
module-loaded?
load-linux-module*
current-module-debugging-port))
;;; Commentary:
;;;
;;; Tools to deal with Linux kernel modules.
;;;
;;; Code:
(define current-module-debugging-port
(make-parameter (%make-void-port "w")))
(define (section-contents elf section)
"Return the contents of SECTION in ELF as a bytevector."
(let* ((modinfo (elf-section-by-name elf ".modinfo"))
(contents (make-bytevector (elf-section-size modinfo))))
(bytevector-copy! (elf-bytes elf) (elf-section-offset modinfo)
contents 0
(elf-section-size modinfo))
contents))
(define %not-nul
(char-set-complement (char-set #\nul)))
(define (nul-separated-string->list str)
"Split STR at occurrences of the NUL character and return the resulting
string list."
(string-tokenize str %not-nul))
(define (key=value->pair str)
"Assuming STR has the form \"KEY=VALUE\", return a pair like (KEY
. \"VALUE\")."
(let ((= (string-index str #\=)))
(cons (string->symbol (string-take str =))
(string-drop str (+ 1 =)))))
(define (modinfo-section-contents file)
"Return the contents of the '.modinfo' section of FILE as a list of
key/value pairs.."
(let* ((bv (call-with-input-file file get-bytevector-all))
(elf (parse-elf bv))
(modinfo (section-contents elf ".modinfo")))
(map key=value->pair
(nul-separated-string->list (utf8->string modinfo)))))
(define %not-comma
(char-set-complement (char-set #\,)))
(define (module-dependencies file)
"Return the list of modules that FILE depends on. The returned list
contains module names, not actual file names."
(let ((info (modinfo-section-contents file)))
(match (assq 'depends info)
(('depends . what)
(string-tokenize what %not-comma)))))
(define dot-ko
(cut string-append <> ".ko"))
(define (ensure-dot-ko name)
"Return NAME with a '.ko' prefix appended, unless it already has it."
(if (string-suffix? ".ko" name)
name
(dot-ko name)))
(define* (recursive-module-dependencies files
#:key (lookup-module dot-ko))
"Return the topologically-sorted list of file names of the modules depended
on by FILES, recursively. File names of modules are determined by applying
LOOKUP-MODULE to the module name."
(let loop ((files files)
(result '())
(visited vlist-null))
(match files
(()
(delete-duplicates (reverse result)))
((head . tail)
(let* ((visited? (vhash-assoc head visited))
(deps (if visited?
'()
(map lookup-module (module-dependencies head))))
(visited (if visited?
visited
(vhash-cons head #t visited))))
(loop (append deps tail)
(append result deps) visited))))))
(define %not-newline
(char-set-complement (char-set #\newline)))
(define (modules-loaded)
"Return the list of names of currently loaded Linux modules."
(let* ((contents (call-with-input-file "/proc/modules"
get-string-all))
(lines (string-tokenize contents %not-newline)))
(match (map string-tokenize lines)
(((modules . _) ...)
modules))))
(define (module-loaded? module)
"Return #t if MODULE is already loaded. MODULE must be a Linux module name,
not a file name."
(member module (modules-loaded)))
(define* (load-linux-module* file
#:key
(recursive? #t)
(lookup-module dot-ko))
"Load Linux module from FILE, the name of a `.ko' file. When RECURSIVE? is
true, load its dependencies first (à la 'modprobe'.) The actual files
containing modules depended on are obtained by calling LOOKUP-MODULE with the
module name."
(define (slurp module)
;; TODO: Use 'mmap' to reduce memory usage.
(call-with-input-file file get-bytevector-all))
(when recursive?
(for-each (cut load-linux-module* <> #:lookup-module lookup-module)
(map lookup-module (module-dependencies file))))
(format (current-module-debugging-port)
"loading Linux module from '~a'...~%" file)
(catch 'system-error
(lambda ()
(load-linux-module (slurp file)))
(lambda args
;; If this module was already loaded and we're in modprobe style, ignore
;; the error.
(unless (and recursive? (= EEXIST (system-error-errno args)))
(apply throw args)))))
;;; linux-modules.scm ends here
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