services: Move 'device-mapping-service' to (gnu system mapped-devices).

* gnu/services/base.scm (device-mapping-service-type)
(device-mapping-service): Move to...
* gnu/system/mapped-devices.scm (device-mapping-service-type):
(device-mapping-service): ... here.  New variables.

1 files changed, 31 insertions, 0 deletions

diff --git a/gnu/system/mapped-devices.scm b/gnu/system/mapped-devices.scm
index dd8e432688..be2d6a4749 100644
--- a/gnu/system/mapped-devices.scm
+++ b/gnu/system/mapped-devices.scm
@@ -19,7 +19,10 @@
 (define-module (gnu system mapped-devices)
   #:use-module (guix gexp)
   #:use-module (guix records)
+  #:use-module (gnu services)
+  #:use-module (gnu services shepherd)
   #:autoload   (gnu packages cryptsetup) (cryptsetup)
+  #:use-module (ice-9 match)
   #:export (mapped-device
             mapped-device?
             mapped-device-source
@@ -31,6 +34,9 @@
             mapped-device-kind-open
             mapped-device-kind-close
 
+            device-mapping-service-type
+            device-mapping-service
+
             luks-device-mapping))
 
 ;;; Commentary:
@@ -56,6 +62,31 @@
 
 
 ;;;
+;;; Device mapping as a Shepherd service.
+;;;
+
+(define device-mapping-service-type
+  (shepherd-service-type
+   'device-mapping
+   (match-lambda
+     ((target open close)
+      (shepherd-service
+       (provision (list (symbol-append 'device-mapping- (string->symbol target))))
+       (requirement '(udev))
+       (documentation "Map a device node using Linux's device mapper.")
+       (start #~(lambda () #$open))
+       (stop #~(lambda _ (not #$close)))
+       (respawn? #f))))))
+
+(define (device-mapping-service target open close)
+  "Return a service that maps device @var{target}, a string such as
+@code{\"home\"} (meaning @code{/dev/mapper/home}).  Evaluate @var{open}, a
+gexp, to open it, and evaluate @var{close} to close it."
+  (service device-mapping-service-type
+           (list target open close)))
+
+
+;;;
 ;;; Common device mappings.
 ;;;