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Diffstat (limited to 'gnu/build/linux-modules.scm')
| -rw-r--r-- | gnu/build/linux-modules.scm | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/gnu/build/linux-modules.scm b/gnu/build/linux-modules.scm new file mode 100644 index 0000000000..a3bc7d6e33 --- /dev/null +++ b/gnu/build/linux-modules.scm @@ -0,0 +1,166 @@ +;;; 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 |