services: dnsmasq: Add pid-file, conf-file and conf-dir configuration fields.

* gnu/services/dns.scm (<dnsmasq-configuration>) [pid-file]: New field
to specify alternate path for dnsmasq PID.
[conf-file]: New field to specify one or more configuration files.
[conf-dir]: New field to read configuration files from a directory.
[extra-options]: Move to the end of the definition as a last resort option.
(dnsmasq-shepherd-service): Use new fields instead of hardcoded values.
* gnu/services/dns.scm: Export all record accessors.
* doc/guix.texi: Document new configuration options.

Change-Id: Iaec361e7d8bfd60af04f023f57d422b55b0c1eea
Signed-off-by: Maxim Cournoyer <maxim.cournoyer@gmail.com>
Modified-by: Maxim Cournoyer <maxim.cournoyer@gmail.com>

doc/guix.texi

@@ -36129,6 +36129,9 @@ value if you intend to run several @command{dnsmasq} instances.
 Likewise, @code{shepherd-requirement} is a list of Shepherd service names
 (symbols) that this service will depend on.
 
+@item @code{pid-file} (default: @code{"/run/dnsmasq.pid"})
+Specify an alternate path for dnsmasq to record its process-id in.
+
 @item @code{no-hosts?} (default: @code{#f})
 When true, don't read the hostnames in /etc/hosts.
 
@@ -36249,6 +36252,16 @@ separated by dashes, e.g.: @samp{01-02-03-04-aa-bb}.  Note that
 resolving MAC addresses is only possible if the client is in the local
 network or obtained a DHCP lease from dnsmasq.
 
+@item @code{conf-file} (default: @code{'()})
+File names of configuration files to use.  Strings and file-like objects
+are accepted.
+
+@item @code{conf-dir} (default: @code{#f})
+Read all the files in the given directory as configuration files.
+Support for @command{dnsmasq} field extensions is not implemented; users
+can use @code{computed-file} to build a directory of files instead.  The
+configuration files are loaded in alphabetical order of file name.
+
 @item @code{extra-options} (default: @code{'()})
 This option provides an ``escape hatch'' for the user to provide arbitrary
 command-line arguments to @command{dnsmasq} as a list of strings.

gnu/services/dns.scm

@@ -55,6 +55,38 @@
 
             dnsmasq-service-type
             dnsmasq-configuration
+            dnsmasq-configuration-package
+            dnsmasq-configuration-shepherd-provision
+            dnsmasq-configuration-shepherd-requirement
+            dnsmasq-configuration-pid-file
+            dnsmasq-configuration-no-hosts?
+            dnsmasq-configuration-port
+            dnsmasq-configuration-local-service?
+            dnsmasq-configuration-listen-address
+            dnsmasq-configuration-resolv-file
+            dnsmasq-configuration-no-resolv?
+            dnsmasq-configuration-forward-private-reverse-lookup?
+            dnsmasq-configuration-query-servers-in-order?
+            dnsmasq-configuration-servers
+            dnsmasq-configuration-servers-file
+            dnsmasq-configuration-addresses
+            dnsmasq-configuration-cache-size
+            dnsmasq-configuration-negative-cache?
+            dnsmasq-configuration-cpe-id
+            dnsmasq-configuration-tftp-enable?
+            dnsmasq-configuration-tftp-no-fail?
+            dnsmasq-configuration-tftp-single-port?
+            dnsmasq-tftp-secure?
+            dnsmasq-tftp-max
+            dnsmasq-tftp-mtu
+            dnsmasq-tftp-no-blocksize?
+            dnsmasq-tftp-lowercase?
+            dnsmasq-tftp-port-range
+            dnsmasq-tftp-root
+            dnsmasq-tftp-unique-root
+            dnsmasq-configuration-conf-file
+            dnsmasq-configuration-conf-dir
+            dnsmasq-configuration-extra-options
 
             unbound-service-type
             unbound-configuration
@@ -752,14 +784,14 @@ cache.size = 100 * MB
                                 (default '(user-processes networking)))
   (no-hosts?        dnsmasq-configuration-no-hosts?
                     (default #f))       ;boolean
+  (pid-file         dnsmasq-configuration-pid-file
+                    (default "/run/dnsmasq.pid")) ;string
   (port             dnsmasq-configuration-port
                     (default 53))       ;integer
   (local-service?   dnsmasq-configuration-local-service?
                     (default #t))       ;boolean
   (listen-addresses dnsmasq-configuration-listen-address
                     (default '()))      ;list of string
-  (extra-options    dnsmasq-configuration-extra-options
-                    (default '()))      ;list of string
   (resolv-file      dnsmasq-configuration-resolv-file
                     (default "/etc/resolv.conf")) ;string
   (no-resolv?       dnsmasq-configuration-no-resolv?
@@ -803,7 +835,13 @@ cache.size = 100 * MB
   (tftp-root        dnsmasq-tftp-root
                     (default "/var/empty,lo")) ;string
   (tftp-unique-root dnsmasq-tftp-unique-root
-                    (default #f)))      ;"" or "ip" or "mac"
+                    (default #f))       ;"" or "ip" or "mac"
+  (conf-file        dnsmasq-configuration-conf-file
+                    (default '()))      ;list of string|file-like
+  (conf-dir         dnsmasq-configuration-conf-dir
+                    (default #f))       ;string|file-like
+  (extra-options    dnsmasq-configuration-extra-options
+                    (default '())))     ;list of string
 
 (define (warn-deprecated-dnsmasq-configuration-provision value)
   (when (pair? value)
@@ -818,6 +856,7 @@ cache.size = 100 * MB
      provision
      shepherd-provision
      shepherd-requirement
+     pid-file
      no-hosts?
      port local-service? listen-addresses
      resolv-file no-resolv?
@@ -829,7 +868,8 @@ cache.size = 100 * MB
      tftp-single-port? tftp-secure?
      tftp-max tftp-mtu tftp-no-blocksize?
      tftp-lowercase? tftp-port-range
-     tftp-root tftp-unique-root extra-options)
+     tftp-root tftp-unique-root
+     conf-file conf-dir extra-options)
     (shepherd-service
      (provision (or provision shepherd-provision))
      (requirement shepherd-requirement)
@@ -838,7 +878,7 @@ cache.size = 100 * MB
                (list
                 #$(file-append package "/sbin/dnsmasq")
                 "--keep-in-foreground"
-                "--pid-file=/run/dnsmasq.pid"
+                (string-append "--pid-file=" #$pid-file)
                 #$@(if no-hosts?
                        '("--no-hosts")
                         '())
@@ -909,8 +949,14 @@ cache.size = 100 * MB
                             (format #f "--tftp-unique-root=~a" tftp-unique-root)
                             (format #f "--tftp-unique-root")))
                        '())
+                #$@(map (lambda (conf-file)
+                          #~(string-append "--conf-file=" #$conf-file))
+                        conf-file)
+                #$@(if conf-dir
+                       (list #~(string-append "--conf-dir=" #$conf-dir))
+                       '())
                 #$@extra-options)
-               #:pid-file "/run/dnsmasq.pid"))
+               #:pid-file #$pid-file))
      (stop #~(make-kill-destructor)))))
 
 (define (dnsmasq-activation config)