Add chrony service

services/chrony.scm

@@ -0,0 +1,59 @@
+(define-module (services chrony)
+  #:use-module (gnu packages admin)
+  #:use-module (gnu packages ntp)
+  #:use-module (gnu services)
+  #:use-module (gnu services shepherd)
+  #:use-module (gnu system shadow)
+  #:use-module (guix gexp)
+  #:use-module (guix modules)
+  #:use-module (guix records)
+  #:export (chrony-service-type chrony-configuration))
+
+(define %chrony-accounts
+  (list (user-group (name "chrony") (system? #t))
+        (user-account
+         (name "chrony")
+         (group "chrony")
+         (system? #t)
+         (comment "chronyd user")
+         (home-directory "/var/lib/chrony")
+         (shell (file-append shadow "/sbin/nologin")))))
+
+(define-record-type* <chrony-configuration>
+  chrony-configuration make-chrony-configuration
+  chrony-configuration?
+  (chrony         chrony-configuration-chrony
+                  (default chrony))
+  (syscall-filter chrony-configuration-syscall-filter
+                  (default "0"))
+  (config-file    chrony-configuration-config-file
+                  (default (plain-file "empty" ""))))
+
+(define (chrony-shepherd-service config)
+  (match-record config <chrony-configuration>
+    (chrony syscall-filter config-file)
+    (list (shepherd-service
+           (provision '(ntpd))
+           (documentation "Run the chrony NTP daemon.")
+           (requirement '(user-processes networking syslogd))
+           (start #~(make-forkexec-constructor
+                     (list (string-append #$chrony "/sbin/chronyd")
+                           "-n" "-u" "chrony"
+                           "-F" #$syscall-filter
+                           "-f" #$config-file)))
+           (stop #~(make-kill-destructor))))))
+
+(define chrony-service-type
+  (service-type (name 'chrony)
+                (extensions
+                 (list (service-extension shepherd-root-service-type
+                                          chrony-shepherd-service)
+                       (service-extension account-service-type
+                                          (const %chrony-accounts))
+                       (service-extension profile-service-type
+                                          (compose list chrony-configuration-chrony))))
+                (default-value (chrony-configuration))
+                (description
+                 "Run @command{chronyd}, a Network Time Protocol (NTP) daemon.
+The daemon will keep the system clock synchronized with that of the given
+servers.")))