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02/05: linux-modules: Add 'device-module-aliases' and related procedures
From: |
Ludovic Courtès |
Subject: |
02/05: linux-modules: Add 'device-module-aliases' and related procedures. |
Date: |
Fri, 2 Mar 2018 07:55:32 -0500 (EST) |
civodul pushed a commit to branch master
in repository guix.
commit 8661ad27435695ef1fbd05f6d9a01330520a3b2e
Author: Ludovic Courtès <address@hidden>
Date: Fri Feb 16 18:51:16 2018 +0100
linux-modules: Add 'device-module-aliases' and related procedures.
* gnu/build/linux-modules.scm (readlink*, stat->device-major)
(stat->device-minor): New procedures.
(%not-slash): New variable.
(read-uevent, device-module-aliases, read-module-aliases)
(current-alias-file, known-module-aliases, matching-modules): New
procedures.
---
gnu/build/linux-modules.scm | 159 +++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 158 insertions(+), 1 deletion(-)
diff --git a/gnu/build/linux-modules.scm b/gnu/build/linux-modules.scm
index 115a17c..4a6d4ff 100644
--- a/gnu/build/linux-modules.scm
+++ b/gnu/build/linux-modules.scm
@@ -19,6 +19,7 @@
(define-module (gnu build linux-modules)
#:use-module (guix elf)
+ #:use-module (guix glob)
#:use-module (guix build syscalls)
#:use-module (rnrs io ports)
#:use-module (rnrs bytevectors)
@@ -26,6 +27,7 @@
#:use-module (srfi srfi-26)
#:use-module (ice-9 vlist)
#:use-module (ice-9 match)
+ #:use-module (ice-9 rdelim)
#:export (dot-ko
ensure-dot-ko
module-dependencies
@@ -34,7 +36,11 @@
module-loaded?
load-linux-module*
- current-module-debugging-port))
+ current-module-debugging-port
+
+ device-module-aliases
+ known-module-aliases
+ matching-modules))
;;; Commentary:
;;;
@@ -213,4 +219,155 @@ appears in BLACK-LIST are not loaded."
(or (and recursive? (= EEXIST (system-error-errno args)))
(apply throw args)))))))
+
+;;;
+;;; Device modules.
+;;;
+
+;; Copied from (guix utils). FIXME: Factorize.
+(define (readlink* file)
+ "Call 'readlink' until the result is not a symlink."
+ (define %max-symlink-depth 50)
+
+ (let loop ((file file)
+ (depth 0))
+ (define (absolute target)
+ (if (absolute-file-name? target)
+ target
+ (string-append (dirname file) "/" target)))
+
+ (if (>= depth %max-symlink-depth)
+ file
+ (call-with-values
+ (lambda ()
+ (catch 'system-error
+ (lambda ()
+ (values #t (readlink file)))
+ (lambda args
+ (let ((errno (system-error-errno args)))
+ (if (or (= errno EINVAL))
+ (values #f file)
+ (apply throw args))))))
+ (lambda (success? target)
+ (if success?
+ (loop (absolute target) (+ depth 1))
+ file))))))
+
+;; See 'major' and 'minor' in <sys/sysmacros.h>.
+
+(define (stat->device-major st)
+ (ash (logand #xfff00 (stat:rdev st)) -8))
+
+(define (stat->device-minor st)
+ (logand #xff (stat:rdev st)))
+
+(define %not-slash
+ (char-set-complement (char-set #\/)))
+
+(define (read-uevent port)
+ "Read a /sys 'uevent' file from PORT and return an alist where each car is a
+key such as 'MAJOR or 'DEVTYPE and each cdr is the corresponding value."
+ (let loop ((result '()))
+ (match (read-line port)
+ ((? eof-object?)
+ (reverse result))
+ (line
+ (loop (cons (key=value->pair line) result))))))
+
+(define (device-module-aliases device)
+ "Return the list of module aliases required by DEVICE, a /dev file name, as
+in this example:
+
+ (device-module-aliases \"/dev/sda\")
+ => (\"scsi:t-0x00\"
\"pci:v00008086d00009D03sv0000103Csd000080FAbc01sc06i01\")
+
+The modules corresponding to these aliases can then be found using
+'matching-modules'."
+ ;; The approach is adapted from
+ ;;
<https://unix.stackexchange.com/questions/97676/how-to-find-the-driver-module-associated-with-a-device-on-linux>.
+ (let* ((st (stat device))
+ (type (stat:type st))
+ (major (stat->device-major st))
+ (minor (stat->device-minor st))
+ (sys-name (string-append "/sys/dev/"
+ (case type
+ ((block-special) "block")
+ ((char-special) "char")
+ (else (symbol->string type)))
+ "/" (number->string major) ":"
+ (number->string minor)))
+ (directory (canonicalize-path (readlink* sys-name))))
+ (let loop ((components (string-tokenize directory %not-slash))
+ (aliases '()))
+ (match components
+ (("sys" "devices" _)
+ (reverse aliases))
+ ((head ... _)
+ (let ((uevent (string-append (string-join components "/" 'prefix)
+ "/uevent")))
+ (if (file-exists? uevent)
+ (let ((props (call-with-input-file uevent read-uevent)))
+ (match (assq-ref props 'MODALIAS)
+ (#f (loop head aliases))
+ (alias (loop head (cons alias aliases)))))
+ (loop head aliases))))))))
+
+(define (read-module-aliases port)
+ "Read from PORT data in the Linux 'modules.alias' file format. Return a
+list of alias/module pairs where each alias is a glob pattern as like the
+result of:
+
+ (compile-glob-pattern \"scsi:t-0x01*\")
+
+and each module is a module name like \"snd_hda_intel\"."
+ (define (comment? str)
+ (string-prefix? "#" str))
+
+ (define (tokenize str)
+ ;; Lines have the form "alias ALIAS MODULE", where ALIAS can contain
+ ;; whitespace. This is why we don't use 'string-tokenize'.
+ (let* ((str (string-trim-both str))
+ (left (string-index str #\space))
+ (right (string-rindex str #\space)))
+ (list (string-take str left)
+ (string-trim-both (substring str left right))
+ (string-trim-both (string-drop str right)))))
+
+ (let loop ((aliases '()))
+ (match (read-line port)
+ ((? eof-object?)
+ (reverse aliases))
+ ((? comment?)
+ (loop aliases))
+ (line
+ (match (tokenize line)
+ (("alias" alias module)
+ (loop (alist-cons (compile-glob-pattern alias) module
+ aliases)))
+ (() ;empty line
+ (loop aliases)))))))
+
+(define (current-alias-file)
+ "Return the absolute file name of the default 'modules.alias' file."
+ (string-append (or (getenv "LINUX_MODULE_DIRECTORY")
+ "/run/booted-system/kernel/lib/modules")
+ "/" (utsname:release (uname))
+ "/" "modules.alias"))
+
+(define* (known-module-aliases #:optional (alias-file (current-alias-file)))
+ "Return the list of alias/module pairs read from ALIAS-FILE. Each alias is
+actually a pattern."
+ (call-with-input-file alias-file read-module-aliases))
+
+(define* (matching-modules alias
+ #:optional (known-aliases (known-module-aliases)))
+ "Return the list of modules that match ALIAS according to KNOWN-ALIASES.
+ALIAS is a string like \"scsi:t-0x00\" as returned by
+'device-module-aliases'."
+ (filter-map (match-lambda
+ ((pattern . module)
+ (and (glob-match? pattern alias)
+ module)))
+ known-aliases))
+
;;; linux-modules.scm ends here