467 lines
17 KiB
Scheme
467 lines
17 KiB
Scheme
;;; GNU Guix --- Functional package management for GNU
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;;; Copyright © 2014, 2016, 2018 Ludovic Courtès <ludo@gnu.org>
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;;; Copyright © 2017 Mathieu Othacehe <m.othacehe@gmail.com>
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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 (gnu build linux-modules)
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#:use-module (guix elf)
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#:use-module (guix glob)
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#:use-module (guix build syscalls)
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#:use-module ((guix build utils) #:select (find-files))
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#:use-module (rnrs io ports)
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#:use-module (rnrs bytevectors)
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#:use-module (srfi srfi-1)
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#:use-module (srfi srfi-11)
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#:use-module (srfi srfi-26)
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#:use-module (ice-9 vlist)
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#:use-module (ice-9 match)
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#:use-module (ice-9 rdelim)
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#:export (dot-ko
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ensure-dot-ko
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module-aliases
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module-dependencies
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module-soft-dependencies
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normalize-module-name
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file-name->module-name
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find-module-file
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recursive-module-dependencies
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modules-loaded
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module-loaded?
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load-linux-module*
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current-module-debugging-port
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device-module-aliases
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known-module-aliases
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matching-modules))
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;;; Commentary:
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;;;
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;;; Tools to deal with Linux kernel modules.
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;;;
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;;; Code:
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(define current-module-debugging-port
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(make-parameter (%make-void-port "w")))
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(define (section-contents elf section)
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"Return the contents of SECTION in ELF as a bytevector."
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(let ((contents (make-bytevector (elf-section-size section))))
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(bytevector-copy! (elf-bytes elf) (elf-section-offset section)
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contents 0
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(elf-section-size section))
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contents))
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(define %not-nul
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(char-set-complement (char-set #\nul)))
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(define (nul-separated-string->list str)
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"Split STR at occurrences of the NUL character and return the resulting
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string list."
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(string-tokenize str %not-nul))
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(define (key=value->pair str)
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"Assuming STR has the form \"KEY=VALUE\", return a pair like (KEY
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. \"VALUE\")."
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(let ((= (string-index str #\=)))
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(cons (string->symbol (string-take str =))
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(string-drop str (+ 1 =)))))
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(define (modinfo-section-contents file)
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"Return the contents of the '.modinfo' section of FILE as a list of
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key/value pairs.."
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(let* ((bv (call-with-input-file file get-bytevector-all))
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(elf (parse-elf bv))
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(section (elf-section-by-name elf ".modinfo"))
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(modinfo (section-contents elf section)))
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(map key=value->pair
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(nul-separated-string->list (utf8->string modinfo)))))
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(define %not-comma
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(char-set-complement (char-set #\,)))
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(define (module-dependencies file)
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"Return the list of modules that FILE depends on. The returned list
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contains module names, not actual file names."
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(let ((info (modinfo-section-contents file)))
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(match (assq 'depends info)
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(('depends . what)
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(string-tokenize what %not-comma)))))
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(define not-softdep-whitespace
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(char-set-complement (char-set #\space #\tab)))
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(define (module-soft-dependencies file)
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"Return the list of modules that can be preloaded, and then the list of
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modules that can be postloaded, of the soft dependencies of module FILE."
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;; TEXT: "pre: baz blubb foo post: bax bar"
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(define (parse-softdep text)
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(let loop ((value '())
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(tokens (string-tokenize text not-softdep-whitespace))
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(section #f))
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(match tokens
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((token rest ...)
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(if (string=? (string-take-right token 1) ":") ; section
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(loop value rest (string-trim-both (string-drop-right token 1)))
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(loop (cons (cons section token) value) rest section)))
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(()
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value))))
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;; Note: Multiple 'softdep sections are allowed.
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(let* ((info (modinfo-section-contents file))
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(entries (concatenate
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(filter-map (match-lambda
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(('softdep . value)
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(parse-softdep value))
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(_ #f))
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(modinfo-section-contents file)))))
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(let-values (((pres posts)
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(partition (match-lambda
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(("pre" . _) #t)
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(("post" . _) #f))
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entries)))
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(values (map (match-lambda
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((_ . value) value))
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pres)
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(map (match-lambda
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((_ . value) value))
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posts)))))
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(define (module-aliases file)
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"Return the list of aliases of module FILE."
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(let ((info (modinfo-section-contents file)))
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(filter-map (match-lambda
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(('alias . value)
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value)
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(_ #f))
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(modinfo-section-contents file))))
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(define dot-ko
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(cut string-append <> ".ko"))
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(define (ensure-dot-ko name)
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"Return NAME with a '.ko' prefix appended, unless it already has it."
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(if (string-suffix? ".ko" name)
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name
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(dot-ko name)))
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(define (normalize-module-name module)
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"Return the \"canonical\" name for MODULE, replacing hyphens with
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underscores."
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;; See 'modname_normalize' in libkmod.
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(string-map (lambda (chr)
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(case chr
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((#\-) #\_)
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(else chr)))
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module))
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(define (file-name->module-name file)
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"Return the module name corresponding to FILE, stripping the trailing '.ko'
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and normalizing it."
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(normalize-module-name (basename file ".ko")))
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(define (find-module-file directory module)
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"Lookup module NAME under DIRECTORY, and return its absolute file name.
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NAME can be a file name with or without '.ko', or it can be a module name.
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Raise an error if it could not be found.
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Module names can differ from file names in interesting ways; for instance,
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module names usually (always?) use underscores as the inter-word separator,
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whereas file names often, but not always, use hyphens. Examples:
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\"usb-storage.ko\", \"serpent_generic.ko\"."
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(define names
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;; List of possible file names. XXX: It would of course be cleaner to
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;; have a database that maps module names to file names and vice versa,
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;; but everyone seems to be doing hacks like this one. Oh well!
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(map ensure-dot-ko
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(delete-duplicates
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(list module
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(normalize-module-name module)
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(string-map (lambda (chr) ;converse of 'normalize-module-name'
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(case chr
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((#\_) #\-)
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(else chr)))
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module)))))
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(match (find-files directory
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(lambda (file stat)
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(member (basename file) names)))
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((file)
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file)
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(()
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(error "kernel module not found" module directory))
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((_ ...)
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(error "several modules by that name" module directory))))
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(define* (recursive-module-dependencies files
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#:key (lookup-module dot-ko))
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"Return the topologically-sorted list of file names of the modules depended
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on by FILES, recursively. File names of modules are determined by applying
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LOOKUP-MODULE to the module name."
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(let loop ((files files)
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(result '())
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(visited vlist-null))
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(match files
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(()
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(delete-duplicates (reverse result)))
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((head . tail)
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(let* ((visited? (vhash-assoc head visited))
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(deps (if visited?
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'()
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(map lookup-module (module-dependencies head))))
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(visited (if visited?
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visited
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(vhash-cons head #t visited))))
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(loop (append deps tail)
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(append result deps) visited))))))
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(define %not-newline
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(char-set-complement (char-set #\newline)))
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(define (modules-loaded)
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"Return the list of names of currently loaded Linux modules."
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(let* ((contents (call-with-input-file "/proc/modules"
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get-string-all))
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(lines (string-tokenize contents %not-newline)))
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(match (map string-tokenize lines)
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(((modules . _) ...)
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modules))))
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(define (module-black-list)
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"Return the black list of modules that must not be loaded. This black list
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is specified using 'modprobe.blacklist=MODULE1,MODULE2,...' on the kernel
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command line; it is honored by libkmod for users that pass
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'KMOD_PROBE_APPLY_BLACKLIST', which includes 'modprobe --use-blacklist' and
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udev."
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(define parameter
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"modprobe.blacklist=")
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(let ((command (call-with-input-file "/proc/cmdline"
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get-string-all)))
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(append-map (lambda (arg)
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(if (string-prefix? parameter arg)
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(string-tokenize (string-drop arg (string-length parameter))
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%not-comma)
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'()))
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(string-tokenize command))))
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(define (module-loaded? module)
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"Return #t if MODULE is already loaded. MODULE must be a Linux module name,
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not a file name."
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(member module (modules-loaded)))
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(define* (load-linux-module* file
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#:key
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(recursive? #t)
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(lookup-module dot-ko)
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(black-list (module-black-list)))
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"Load Linux module from FILE, the name of a '.ko' file; return true on
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success, false otherwise. When RECURSIVE? is true, load its dependencies
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first (à la 'modprobe'.) The actual files containing modules depended on are
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obtained by calling LOOKUP-MODULE with the module name. Modules whose name
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appears in BLACK-LIST are not loaded."
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(define (black-listed? module)
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(let ((result (member module black-list)))
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(when result
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(format (current-module-debugging-port)
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"not loading module '~a' because it's black-listed~%"
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module))
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result))
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(define (load-dependencies file)
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(let ((dependencies (module-dependencies file)))
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(every (cut load-linux-module* <>
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#:lookup-module lookup-module
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#:black-list black-list)
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(map lookup-module dependencies))))
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(and (not (black-listed? (file-name->module-name file)))
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(or (not recursive?)
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(load-dependencies file))
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(let ((fd #f))
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(format (current-module-debugging-port)
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"loading Linux module from '~a'...~%" file)
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(catch 'system-error
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(lambda ()
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(set! fd (open-fdes file O_RDONLY))
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(load-linux-module/fd fd)
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(close-fdes fd)
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#t)
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(lambda args
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;; If this module was already loaded and we're in modprobe style, ignore
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;; the error.
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(when fd (close-fdes fd))
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(or (and recursive? (= EEXIST (system-error-errno args)))
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(apply throw args)))))))
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;;;
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;;; Device modules.
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;;;
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;; Copied from (guix utils). FIXME: Factorize.
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(define (readlink* file)
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"Call 'readlink' until the result is not a symlink."
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(define %max-symlink-depth 50)
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(let loop ((file file)
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(depth 0))
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(define (absolute target)
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(if (absolute-file-name? target)
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target
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(string-append (dirname file) "/" target)))
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(if (>= depth %max-symlink-depth)
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file
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(call-with-values
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(lambda ()
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(catch 'system-error
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(lambda ()
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(values #t (readlink file)))
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(lambda args
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(let ((errno (system-error-errno args)))
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(if (or (= errno EINVAL))
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(values #f file)
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(apply throw args))))))
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(lambda (success? target)
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(if success?
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(loop (absolute target) (+ depth 1))
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file))))))
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;; See 'major' and 'minor' in <sys/sysmacros.h>.
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(define (stat->device-major st)
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(ash (logand #xfff00 (stat:rdev st)) -8))
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(define (stat->device-minor st)
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(logand #xff (stat:rdev st)))
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(define %not-slash
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(char-set-complement (char-set #\/)))
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(define (read-uevent port)
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"Read a /sys 'uevent' file from PORT and return an alist where each car is a
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key such as 'MAJOR or 'DEVTYPE and each cdr is the corresponding value."
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(let loop ((result '()))
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(match (read-line port)
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((? eof-object?)
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(reverse result))
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(line
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(loop (cons (key=value->pair line) result))))))
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(define (device-module-aliases device)
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"Return the list of module aliases required by DEVICE, a /dev file name, as
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in this example:
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(device-module-aliases \"/dev/sda\")
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=> (\"scsi:t-0x00\" \"pci:v00008086d00009D03sv0000103Csd000080FAbc01sc06i01\")
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The modules corresponding to these aliases can then be found using
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'matching-modules'."
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;; The approach is adapted from
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;; <https://unix.stackexchange.com/questions/97676/how-to-find-the-driver-module-associated-with-a-device-on-linux>.
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(let* ((st (stat device))
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(type (stat:type st))
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(major (stat->device-major st))
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(minor (stat->device-minor st))
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(sys-name (string-append "/sys/dev/"
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(case type
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((block-special) "block")
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((char-special) "char")
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(else (symbol->string type)))
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"/" (number->string major) ":"
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(number->string minor)))
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(directory (canonicalize-path (readlink* sys-name))))
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(let loop ((components (string-tokenize directory %not-slash))
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(aliases '()))
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(match components
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(("sys" "devices" _)
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(reverse aliases))
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((head ... _)
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(let ((uevent (string-append (string-join components "/" 'prefix)
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"/uevent")))
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(if (file-exists? uevent)
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(let ((props (call-with-input-file uevent read-uevent)))
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(match (assq-ref props 'MODALIAS)
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(#f (loop head aliases))
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(alias (loop head (cons alias aliases)))))
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(loop head aliases))))))))
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(define (read-module-aliases port)
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"Read from PORT data in the Linux 'modules.alias' file format. Return a
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list of alias/module pairs where each alias is a glob pattern as like the
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result of:
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(string->compiled-sglob \"scsi:t-0x01*\")
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and each module is a module name like \"snd_hda_intel\"."
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(define (comment? str)
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(string-prefix? "#" str))
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(define (tokenize str)
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;; Lines have the form "alias ALIAS MODULE", where ALIAS can contain
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;; whitespace. This is why we don't use 'string-tokenize'.
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(let* ((str (string-trim-both str))
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(left (string-index str #\space))
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(right (string-rindex str #\space)))
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(list (string-take str left)
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(string-trim-both (substring str left right))
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(string-trim-both (string-drop str right)))))
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(let loop ((aliases '()))
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(match (read-line port)
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((? eof-object?)
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(reverse aliases))
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((? comment?)
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(loop aliases))
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(line
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(match (tokenize line)
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(("alias" alias module)
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(loop (alist-cons (string->compiled-sglob alias) module
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aliases)))
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(() ;empty line
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(loop aliases)))))))
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(define (current-kernel-directory)
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"Return the directory of the currently running Linux kernel."
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(string-append (or (getenv "LINUX_MODULE_DIRECTORY")
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"/run/booted-system/kernel/lib/modules")
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"/" (utsname:release (uname))))
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(define (current-alias-file)
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"Return the absolute file name of the default 'modules.alias' file."
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(string-append (current-kernel-directory) "/modules.alias"))
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(define* (known-module-aliases #:optional (alias-file (current-alias-file)))
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"Return the list of alias/module pairs read from ALIAS-FILE. Each alias is
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actually a pattern."
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(call-with-input-file alias-file read-module-aliases))
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(define* (matching-modules alias
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#:optional (known-aliases (known-module-aliases)))
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"Return the list of modules that match ALIAS according to KNOWN-ALIASES.
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ALIAS is a string like \"scsi:t-0x00\" as returned by
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'device-module-aliases'."
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(filter-map (match-lambda
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((pattern . module)
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(and (glob-match? pattern alias)
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module)))
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known-aliases))
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;;; linux-modules.scm ends here
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