summaryrefslogtreecommitdiff
path: root/gnu/services/avahi.scm
blob: 562005c22c741d9effa7c01d45e6f8d94362f638 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
;;;
;;; 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 avahi)
  #:use-module (gnu services)
  #:use-module (gnu services base)
  #:use-module (gnu services shepherd)
  #:use-module (gnu services dbus)
  #:use-module (gnu system shadow)
  #:use-module (gnu packages avahi)
  #:use-module (gnu packages admin)
  #:use-module (guix records)
  #:use-module (guix gexp)
  #:export (avahi-service
            avahi-service-type))

;;; Commentary:
;;;
;;; This module provides service definitions for the Avahi
;;; "zero-configuration" tool set.
;;;
;;; Code:

  ;; TODO: Export.
(define-record-type* <avahi-configuration>
  avahi-configuration make-avahi-configuration
  avahi-configuration?
  (avahi             avahi-configuration-avahi    ;<package>
                     (default avahi))
  (debug?            avahi-configuration-debug?   ;Boolean
                     (default #f))
  (host-name         avahi-configuration-host-name) ;string
  (publish?          avahi-configuration-publish?)  ;Boolean
  (ipv4?             avahi-configuration-ipv4?)     ;Boolean
  (ipv6?             avahi-configuration-ipv6?)     ;Boolean
  (wide-area?        avahi-configuration-wide-area?) ;Boolean
  (domains-to-browse avahi-configuration-domains-to-browse)) ;list of strings

(define* (configuration-file config)
  "Return an avahi-daemon configuration file based on CONFIG, an
<avahi-configuration>."
  (define (bool value)
    (if value "yes\n" "no\n"))

  (define host-name (avahi-configuration-host-name config))

  (plain-file "avahi-daemon.conf"
              (string-append
               "[server]\n"
               (if host-name
                   (string-append "host-name=" host-name "\n")
                   "")

               "browse-domains=" (string-join
                                  (avahi-configuration-domains-to-browse
                                   config))
               "\n"
               "use-ipv4=" (bool (avahi-configuration-ipv4? config))
               "use-ipv6=" (bool (avahi-configuration-ipv6? config))
               "[wide-area]\n"
               "enable-wide-area=" (bool (avahi-configuration-wide-area? config))
               "[publish]\n"
               "disable-publishing="
               (bool (not (avahi-configuration-publish? config))))))

(define %avahi-accounts
  ;; Account and group for the Avahi daemon.
  (list (user-group (name "avahi") (system? #t))
        (user-account
         (name "avahi")
         (group "avahi")
         (system? #t)
         (comment "Avahi daemon user")
         (home-directory "/var/empty")
         (shell #~(string-append #$shadow "/sbin/nologin")))))

(define %avahi-activation
  ;; Activation gexp.
  #~(begin
      (use-modules (guix build utils))
      (mkdir-p "/var/run/avahi-daemon")))

(define (avahi-shepherd-service config)
  "Return a list of <shepherd-service> for CONFIG."
  (let ((config (configuration-file config))
        (debug? (avahi-configuration-debug? config))
        (avahi  (avahi-configuration-avahi config)))
    (list (shepherd-service
           (documentation "Run the Avahi mDNS/DNS-SD responder.")
           (provision '(avahi-daemon))
           (requirement '(dbus-system networking))

           (start #~(make-forkexec-constructor
                     (list (string-append #$avahi "/sbin/avahi-daemon")
                           "--daemonize"
                           #$@(if debug? #~("--debug") #~())
                           "-f" #$config)
                     #:pid-file "/var/run/avahi-daemon/pid"))
           (stop #~(make-kill-destructor))))))

(define avahi-service-type
  (let ((avahi-package (compose list avahi-configuration-avahi)))
    (service-type (name 'avahi)
                  (extensions
                   (list (service-extension shepherd-root-service-type
                                            avahi-shepherd-service)
                         (service-extension dbus-root-service-type
                                            avahi-package)
                         (service-extension account-service-type
                                            (const %avahi-accounts))
                         (service-extension activation-service-type
                                            (const %avahi-activation))
                         (service-extension nscd-service-type
                                            (const (list nss-mdns)))

                         ;; Provide 'avahi-browse', 'avahi-resolve', etc. in
                         ;; the system profile.
                         (service-extension profile-service-type
                                            avahi-package))))))

(define* (avahi-service #:key (avahi avahi) debug?
                        host-name
                        (publish? #t)
                        (ipv4? #t) (ipv6? #t)
                        wide-area?
                        (domains-to-browse '()))
  "Return a service that runs @command{avahi-daemon}, a system-wide
mDNS/DNS-SD responder that allows for service discovery and
\"zero-configuration\" host name lookups (see @uref{http://avahi.org/}), and
extends the name service cache daemon (nscd) so that it can resolve
@code{.local} host names using
@uref{http://0pointer.de/lennart/projects/nss-mdns/, nss-mdns}.  Additionally,
add the @var{avahi} package to the system profile so that commands such as
@command{avahi-browse} are directly usable.

If @var{host-name} is different from @code{#f}, use that as the host name to
publish for this machine; otherwise, use the machine's actual host name.

When @var{publish?} is true, publishing of host names and services is allowed;
in particular, avahi-daemon will publish the machine's host name and IP
address via mDNS on the local network.

When @var{wide-area?} is true, DNS-SD over unicast DNS is enabled.

Boolean values @var{ipv4?} and @var{ipv6?} determine whether to use IPv4/IPv6
sockets."
  (service avahi-service-type
           (avahi-configuration
            (avahi avahi) (debug? debug?) (host-name host-name)
            (publish? publish?) (ipv4? ipv4?) (ipv6? ipv6?)
            (wide-area? wide-area?)
            (domains-to-browse domains-to-browse))))

;;; avahi.scm ends here