[PATCH] Export udev-configuration functions.

[Ricardo Wurmus]

Hi Guix,

as I tried to add a custom udev rule I noticed that I could only really
do this when the udev-configuration accessor functions are exported.

In my system configuration I first created the new udev rule (that’s all
a bit verbose, unfortunately), which is almost identical to the
‘kvm-udev-rule’:

~~~~~~~~~~~~~~~~
(define (avrispmkii-udev-rule)
  "Return a directory with a udev rule that sets the group owner and
group write permissions on the node matching the AVRISPmkII
microcontroller programming device."
  (computed-file "avrispmkii-rules"
                 #~(begin
                     (use-modules (guix build utils))

                     (define rules.d
                       (string-append #$output "/lib/udev/rules.d"))

                     (mkdir-p rules.d)
                     (call-with-output-file
                         (string-append rules.d "/90-avrispmkii.rules")
                       (lambda (port)
                         (display "\
SUBSYSTEM!=\"usb\", ACTION!=\"add\", GOTO=\"avrisp_end\"

# Atmel Corp. JTAG ICE mkII
ATTR{idVendor}==\"03eb\", ATTR{idProduct}==\"2103\", MODE=\"660\", 
GROUP=\"dialout\"
# Atmel Corp. AVRISP mkII
ATTR{idVendor}==\"03eb\", ATTR{idProduct}==\"2104\", MODE=\"660\", 
GROUP=\"dialout\"
# Atmel Corp. Dragon
ATTR{idVendor}==\"03eb\", ATTR{idProduct}==\"2107\", MODE=\"660\", 
GROUP=\"dialout\"

LABEL=\"avrisp_end\"\n" port))))
                 #:modules '((guix build utils))))
~~~~~~~~~~~~~~~~

Then I replaced %desktop-services to amend the service of
‘udev-service-type’:

~~~~~~~~~~~~~~~~
(modify-services %desktop-services
  (udev-service-type config =>
                     (udev-configuration
                      (inherit config)
                      (rules (append (udev-configuration-rules config)
                                     (list (avrispmkii-udev-rule)))))))
~~~~~~~~~~~~~~~~

As you can see I need ‘udev-configuration’ to create a new
configuration, and ‘udev-configuration-rules’ to append my new rule to
the existing rules.

The attached patch just exports ‘udev-configuration’,
‘udev-configuration?’ (why not?), and ‘udev-configuration-rules’.

~~ Ricardo

>From 46091d6045443a1bedbd1ca37e8ac31c1399d551 Mon Sep 17 00:00:00 2001
From: Ricardo Wurmus <address@hidden>
Date: Wed, 18 Nov 2015 12:17:42 +0100
Subject: [PATCH] services: Export udev-configuration procedures.

* gnu/services/base.scm (udev-configuration, udev-configuration?,
  udev-configuration-rules): Export.
---
 gnu/services/base.scm | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/gnu/services/base.scm b/gnu/services/base.scm
index b2bf7d9..bb5854d 100644
--- a/gnu/services/base.scm
+++ b/gnu/services/base.scm
@@ -51,6 +51,10 @@
             host-name-service
             console-keymap-service
             console-font-service
+
+            udev-configuration
+            udev-configuration?
+            udev-configuration-rules
             udev-service-type
             udev-service
 
-- 
2.5.0