[bug#72398,v6] services: Add readymedia-service-type.

diff --git a/doc/guix.texi b/doc/guix.texi
index 981ffb8c58..9b193bde23 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -41635,6 +41635,111 @@  Miscellaneous Services
 
 @end deftp
 
+@c %end of fragment
+
+@cindex DLNA/UPnP
+@subsubheading DLNA/UPnP Services
+
+The @code{(gnu services upnp)} module offers services related to UPnP
+(Universal Plug and Play) and DLNA (Digital Living Network Alliance),
+networking protocols that can be used for media streaming and device
+interoperability within a local network.  For now, this module
+provides the @code{readymedia-service-type}.
+
+@uref{https://sourceforge.net/projects/minidlna/, ReadyMedia}
+(formerly known as MiniDLNA) is a DLNA/UPnP-AV media server.  The
+project's daemon, @code{minidlnad}, can serve media files (audio,
+pictures, and video) to DLNA/UPnP-AV clients available in the network.
+@code{readymedia-service-type} is a Guix service that wraps around
+ReadyMedia's @code{minidlnad}.
+
+Consider the following configuration:
+
+@lisp
+(use-service-modules upnp @dots{})
+
+(operating-system
+  ;; @dots{}
+  (services
+   (list
+    (service readymedia-service-type
+             (readymedia-configuration
+              (media-directoriess
+               (list
+                (readymedia-media-directory (path "/media/audio")
+                                            (types '(A)))
+                (readymedia-media-directory (path "/media/video")
+                                            (types '(V)))
+                (readymedia-media-directory (path "/media/misc"))))
+              (extra-config '(("notify_interval" . 60)))))
+    ;; @dots{}
+    )))
+@end lisp
+
+This sets up the ReadyMedia daemon to serve files from the media
+folders specified in @code{media-directories}.  The
+@code{media-directories} field is mandatory.  All other fields (such
+as network ports and the server name) come with a predefined default
+and can be omitted.
+
+@c %start of fragment
+
+@deftp {Data Type} readymedia-configuration
+Available @code{readymedia-configuration} fields are:
+
+@table @asis
+@item @code{readymedia} (default: @code{readymedia}) (type: package)
+The ReadyMedia package to be used for the service.
+
+@item @code{friendly-name} (default: @code{#f}) (type: maybe-string)
+A custom name that will be displayed on connected clients.
+
+@item @code{media-directories} (type: list)
+The list of media folders to serve content from.  Each item is a
+@code{readymedia-media-directory}.
+
+@item @code{cache-directory} (default: @code{"/var/cache/readymedia"}) (type: string)
+A folder for ReadyMedia's cache files.  If not existing already, the
+folder will be created as part of the service activation and the
+ReadyMedia user will be assigned ownership.
+
+@item @code{log-directory} (default: @code{"/var/log/readymedia"}) (type: string)
+A folder for ReadyMedia's log files.  If not existing already, the
+folder will be created as part of the service activation and the
+ReadyMedia user will be assigned ownership.
+
+@item @code{port} (default: @code{#f}) (type: maybe-integer)
+A custom port that the service will be listening on.
+
+@item @code{extra-config} (default: @code{'()}) (type: alist)
+An association list of further options, as accepted by ReadyMedia.
+
+@end table
+
+@end deftp
+
+@c %end of fragment
+
+@c %start of fragment
+
+@deftp {Data Type} readymedia-media-directory
+A @code{media-directories} entry includes a folder @code{path} and,
+optionally, the @code{types} of media files included within the
+folder.
+
+@table @asis
+@item @code{path} (type: string)
+The media folder location.
+
+@item @code{types} (default: @code{'()}) (type: list)
+A list indicating the types of file included in the media folder.
+Valid values are combinations of individual media types, i.e. symbol
+@code{A} for audio, @code{P} for pictures, @code{V} for video.  An
+empty list means no type specified.
+
+@end table
+
+@end deftp
 
 @c %end of fragment
 
diff --git a/gnu/local.mk b/gnu/local.mk
index ed630041ff..c65e9373f1 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -754,6 +754,7 @@  GNU_SYSTEM_MODULES =				\
   %D%/services/syncthing.scm			\
   %D%/services/sysctl.scm			\
   %D%/services/telephony.scm			\
+  %D%/services/upnp.scm				\
   %D%/services/version-control.scm              \
   %D%/services/vnc.scm				\
   %D%/services/vpn.scm				\
@@ -844,6 +845,7 @@  GNU_SYSTEM_MODULES =				\
   %D%/tests/singularity.scm			\
   %D%/tests/ssh.scm				\
   %D%/tests/telephony.scm		        \
+  %D%/tests/upnp.scm			        \
   %D%/tests/version-control.scm			\
   %D%/tests/virtualization.scm			\
   %D%/tests/vnc.scm				\
diff --git a/gnu/services/upnp.scm b/gnu/services/upnp.scm
new file mode 100644
index 0000000000..ad13f97827
--- /dev/null
+++ b/gnu/services/upnp.scm
@@ -0,0 +1,213 @@ 
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2024 Fabio Natali <me@fabionatali.com>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (gnu services upnp)
+  #:use-module (gnu build linux-container)
+  #:use-module (gnu packages admin)
+  #:use-module (gnu packages upnp)
+  #:use-module (gnu services admin)
+  #:use-module (gnu services base)
+  #:use-module (gnu services shepherd)
+  #:use-module (gnu services)
+  #:use-module (gnu system file-systems)
+  #:use-module (gnu system shadow)
+  #:use-module (guix gexp)
+  #:use-module (guix least-authority)
+  #:use-module (guix records)
+  #:use-module (ice-9 match)
+  #:export (%readymedia-default-cache-directory
+            %readymedia-default-log-directory
+            %readymedia-default-port
+            %readymedia-log-file
+            %readymedia-user-account
+            %readymedia-user-group
+            readymedia-configuration
+            readymedia-configuration-cache-directory
+            readymedia-configuration-extra-config
+            readymedia-configuration-friendly-name
+            readymedia-configuration-log-directory
+            readymedia-configuration-media-directories
+            readymedia-configuration-port
+            readymedia-configuration-readymedia
+            readymedia-configuration?
+            readymedia-media-directory
+            readymedia-media-directory-path
+            readymedia-media-directory-types
+            readymedia-media-directory?
+            readymedia-service-type))
+
+;;; Commentary:
+;;;
+;;; UPnP services.
+;;;
+;;; Code:
+
+(define %readymedia-default-cache-directory "/var/cache/readymedia")
+(define %readymedia-default-log-directory "/var/log/readymedia")
+(define %readymedia-log-file "minidlna.log")
+(define %readymedia-user-group "readymedia")
+(define %readymedia-user-account "readymedia")
+
+(define-record-type* <readymedia-configuration>
+  readymedia-configuration make-readymedia-configuration
+  readymedia-configuration?
+  (readymedia readymedia-configuration-readymedia
+              (default readymedia))
+  (cache-directory readymedia-configuration-cache-directory
+                   (default %readymedia-default-cache-directory))
+  (log-directory readymedia-configuration-log-directory
+                 (default %readymedia-default-log-directory))
+  (friendly-name readymedia-configuration-friendly-name
+                 (default #f))
+  (media-directories readymedia-configuration-media-directories)
+  (port readymedia-configuration-port
+        (default #f))
+  (extra-config readymedia-configuration-extra-config
+                (default '())))
+
+;; READYMEDIA-MEDIA-DIR is a record that indicates the path of a media folder
+;; and the types of media included within it. Allowed individual types are the
+;; symbols 'A' for audio, 'V' for video, and 'P' for pictures. The types field
+;; can contain any combination of individual types; an empty list means no type
+;; specified.
+(define-record-type* <readymedia-media-directory>
+  readymedia-media-directory make-readymedia-media-directory
+  readymedia-media-directory?
+  (path readymedia-media-directory-path)
+  (types readymedia-media-directory-types (default '())))
+
+(define (readymedia-media-directory->string entry)
+  "Convert a media-directory ENTRY to a ReadyMedia/MiniDLNA media dir string."
+  (match-record
+   entry <readymedia-media-directory> (path types)
+   (if (null? types)
+       (format #f "media_dir=~a" path)
+       (format #f
+               "media_dir=~a,~a"
+               (string-join (map symbol->string types) "")
+               path))))
+
+(define (readymedia-extra-config-entry->string entry)
+  "Convert a extra-config ENTRY to a ReadyMedia/MiniDLNA configuration string."
+  (let ((key (car entry))
+        (value (cdr entry)))
+    (format #f "~a=~a" key value)))
+
+(define (readymedia-configuration->config-file config)
+  "Return the ReadyMedia/MiniDLNA configuration file corresponding to CONFIG."
+  (let ((friendly-name (readymedia-configuration-friendly-name config))
+        (media-directories (readymedia-configuration-media-directories config))
+        (cache-directory (readymedia-configuration-cache-directory config))
+        (log-directory (readymedia-configuration-log-directory config))
+        (port (readymedia-configuration-port config))
+        (extra-config (readymedia-configuration-extra-config config)))
+    (mixed-text-file
+     "minidlna.conf"
+     "db_dir=" cache-directory "\n"
+     "log_dir=" log-directory "\n"
+     (if friendly-name (format #f "friendly_name=~a\n" friendly-name) "")
+     (if port (format #f "port=~a\n" port) "")
+     (string-join
+      (map readymedia-media-directory->string media-directories) "\n" 'suffix)
+     (string-join
+      (map readymedia-extra-config-entry->string extra-config) "\n" 'suffix))))
+
+(define (readymedia-shepherd-service config)
+  "Return a least-authority ReadyMedia/MiniDLNA Shepherd service."
+  (let* ((minidlna-conf (readymedia-configuration->config-file config))
+         (media-directories (readymedia-configuration-media-directories config))
+         (cache-directory (readymedia-configuration-cache-directory config))
+         (log-directory (readymedia-configuration-log-directory config))
+         (log-file (string-append log-directory "/" %readymedia-log-file))
+         (readymedia (least-authority-wrapper
+                      (file-append
+                       (readymedia-configuration-readymedia config)
+                       "/sbin/minidlnad")
+                      #:name "minidlna"
+                      #:mappings
+                      (cons* (file-system-mapping
+                              (source cache-directory)
+                              (target source)
+                              (writable? #t))
+                             (file-system-mapping
+                              (source log-directory)
+                              (target source)
+                              (writable? #t))
+                             (file-system-mapping
+                              (source minidlna-conf)
+                              (target source))
+                             (map
+                              (lambda (e)
+                                (file-system-mapping
+                                 (source (readymedia-media-directory-path e))
+                                 (target source)
+                                 (writable? #f)))
+                              media-directories))
+                      #:namespaces (delq 'net %namespaces))))
+    (list (shepherd-service
+           (documentation "Run the ReadyMedia/MiniDLNA daemon.")
+           (provision '(readymedia))
+           (requirement '(networking user-processes))
+           (start
+            #~(make-forkexec-constructor
+               ;; "-S" is to daemonise minidlnad.
+               (list #$readymedia "-f" #$minidlna-conf "-S")
+               #:log-file #$log-file
+               #:user #$%readymedia-user-account
+               #:group #$%readymedia-user-group))
+           (stop #~(make-kill-destructor))))))
+
+(define readymedia-accounts
+  (list (user-group
+         (name "readymedia")
+         (system? #t))
+        (user-account
+         (name "readymedia")
+         (group "readymedia")
+         (system? #t)
+         (comment "ReadyMedia/MiniDLNA daemon user")
+         (home-directory "/var/empty")
+         (shell (file-append shadow "/sbin/nologin")))))
+
+(define (readymedia-activation config)
+  "Set up directories for ReadyMedia/MiniDLNA."
+  (let ((cache-directory (readymedia-configuration-cache-directory config))
+        (log-directory (readymedia-configuration-log-directory config))
+        (media-directories (readymedia-configuration-media-directories config)))
+    #~(begin
+        (use-modules (guix build utils))
+        (let* ((user (getpw #$%readymedia-user-account))
+               (dirs (list #$cache-directory
+                           #$log-directory
+                           #$@(map (lambda (e)
+                                     (readymedia-media-directory-path e))
+                                   media-directories)))
+               (init-directory (lambda (d) (unless (file-exists? d)
+                                             (mkdir-p/perms d user #o755)))))
+          (for-each init-directory dirs)))))
+
+(define readymedia-service-type
+  (service-type
+   (name 'readymedia)
+   (extensions
+    (list
+     (service-extension shepherd-root-service-type readymedia-shepherd-service)
+     (service-extension account-service-type (const readymedia-accounts))
+     (service-extension activation-service-type readymedia-activation)))
+   (description
+    "Run @command{minidlnad}, the ReadyMedia/MiniDLNA media server.")))
diff --git a/gnu/tests/upnp.scm b/gnu/tests/upnp.scm
new file mode 100644
index 0000000000..8e92594901
--- /dev/null
+++ b/gnu/tests/upnp.scm
@@ -0,0 +1,178 @@ 
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2024 Fabio Natali <me@fabionatali.com>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (gnu tests upnp)
+  #:use-module (gnu services)
+  #:use-module (gnu services networking)
+  #:use-module (gnu services upnp)
+  #:use-module (gnu system vm)
+  #:use-module (gnu tests)
+  #:use-module (guix gexp)
+  #:export (%test-readymedia))
+
+(define %readymedia-cache-file "files.db")
+(define %readymedia-cache-path
+  (string-append %readymedia-default-cache-directory
+                 "/"
+                 %readymedia-cache-file))
+(define %readymedia-log-path
+  (string-append %readymedia-default-log-directory
+                 "/"
+                 %readymedia-log-file))
+(define %readymedia-default-port 8200)
+(define %readymedia-media-directory "/media")
+(define %readymedia-configuration-test
+  (readymedia-configuration
+   (media-directories
+    (list
+     (readymedia-media-directory (path %readymedia-media-directory)
+                                 (types '(A V)))))))
+
+(define (run-readymedia-test)
+  (define os
+    (marionette-operating-system
+     (simple-operating-system
+      (service dhcp-client-service-type)
+      (service readymedia-service-type
+               %readymedia-configuration-test))
+     #:imported-modules '((gnu services herd)
+                          (json parser))
+     #:requirements '(readymedia)))
+
+  (define test
+    (with-imported-modules '((gnu build marionette))
+      #~(begin
+          (use-modules (gnu build marionette)
+                       (srfi srfi-64))
+
+          (define marionette
+            (make-marionette
+             (list #$(virtual-machine
+                      (operating-system os)
+                      (port-forwardings '())))))
+
+          (test-runner-current (system-test-runner #$output))
+          (test-begin "readymedia")
+
+          ;; ReadyMedia user.
+          (test-assert "ReadyMedia user exists"
+            (marionette-eval
+             '(begin
+                (getpwnam #$%readymedia-user-account)
+                #t)
+             marionette))
+          (test-assert "ReadyMedia group exists"
+            (marionette-eval
+             '(begin
+                (getgrnam #$%readymedia-user-group)
+                #t)
+             marionette))
+
+          ;; Cache directory and file.
+          (test-assert "cache directory exists"
+            (marionette-eval
+             '(eq? (stat:type (stat #$%readymedia-default-cache-directory))
+                   'directory)
+             marionette))
+          (test-assert "cache directory has correct ownership"
+            (marionette-eval
+             '(let ((cache-dir (stat #$%readymedia-default-cache-directory))
+                    (user (getpwnam #$%readymedia-user-account)))
+                (and (eqv? (stat:uid cache-dir) (passwd:uid user))
+                     (eqv? (stat:gid cache-dir) (passwd:gid user))))
+             marionette))
+          (test-assert "cache directory has expected permissions"
+            (marionette-eval
+             '(eqv? (stat:perms (stat #$%readymedia-default-cache-directory))
+                    #o755)
+             marionette))
+          (test-assert "cache file exists"
+            (marionette-eval
+             '(begin
+                ;; Allow some time for the file to be created.
+                (sleep 2)
+                (file-exists? #$%readymedia-cache-path))
+             marionette))
+          (test-assert "cache file has expected permissions"
+            (marionette-eval
+             '(begin
+                (eqv? (stat:perms (stat #$%readymedia-cache-path))
+                      #o644))
+             marionette))
+          (test-assert "cache file is non-empty"
+            (marionette-eval
+             '(begin
+                (> (stat:size (stat #$%readymedia-cache-path)) 0))
+             marionette))
+
+          ;; Log directory and file.
+          (test-assert "log directory exists"
+            (marionette-eval
+             '(eq? (stat:type (stat #$%readymedia-default-log-directory))
+                   'directory)
+             marionette))
+          (test-assert "log directory has correct ownership"
+            (marionette-eval
+             '(let ((log-dir (stat #$%readymedia-default-log-directory))
+                    (user (getpwnam #$%readymedia-user-account)))
+                (and (eqv? (stat:uid log-dir) (passwd:uid user))
+                     (eqv? (stat:gid log-dir) (passwd:gid user))))
+             marionette))
+          (test-assert "log directory has expected permissions"
+            (marionette-eval
+             '(eqv? (stat:perms (stat #$%readymedia-default-log-directory))
+                    #o755)
+             marionette))
+          (test-assert "log file exists"
+            (marionette-eval
+             '(file-exists? #$%readymedia-log-path)
+             marionette))
+          (test-assert "log file has expected permissions"
+            (marionette-eval
+             '(eqv? (stat:perms (stat #$%readymedia-log-path))
+                    #o640)
+             marionette))
+          (test-assert "log file is non-empty"
+            (marionette-eval
+             '(> (stat:size (stat #$%readymedia-log-path)) 0)
+             marionette))
+
+          ;; Service.
+          (test-assert "ReadyMedia service is running"
+            (marionette-eval
+             '(begin
+                (use-modules (gnu services herd)
+                             (srfi srfi-1))
+                (live-service-running
+                 (find (lambda (live-service)
+                         (memq 'readymedia
+                               (live-service-provision live-service)))
+                       (current-services))))
+             marionette))
+          (test-assert "ReadyMedia service is listening for connections"
+            (wait-for-tcp-port #$%readymedia-default-port marionette))
+
+          (test-end))))
+
+  (gexp->derivation "readymedia-test" test))
+
+(define %test-readymedia
+  (system-test
+   (name "readymedia")
+   (description "Test the ReadyMedia service.")
+   (value (run-readymedia-test))))