aboutsummaryrefslogtreecommitdiff
path: root/gnu/services/dbus.scm
blob: e4ecd961c57520a45ff2460dad23867e873150bf (about) (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
170
171
172
173
174
175
176
177
178
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2013, 2014, 2015 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 dbus)
  #:use-module (gnu services)
  #:use-module (gnu services dmd)
  #:use-module (gnu system shadow)
  #:use-module (gnu packages glib)
  #:use-module (gnu packages admin)
  #:use-module (guix gexp)
  #:use-module (guix records)
  #:use-module (srfi srfi-1)
  #:use-module (ice-9 match)
  #:export (dbus-root-service-type
            dbus-service))

;;;
;;; D-Bus.
;;;

(define-record-type* <dbus-configuration>
  dbus-configuration make-dbus-configuration
  dbus-configuration?
  (dbus      dbus-configuration-dbus              ;<package>
             (default dbus))
  (services  dbus-configuration-services          ;list of <package>
             (default '())))

(define (dbus-configuration-directory dbus services)
  "Return a configuration directory for @var{dbus} that includes the
@code{etc/dbus-1/system.d} directories of each package listed in
@var{services}."
  (define build
    #~(begin
        (use-modules (sxml simple)
                     (srfi srfi-1))

        (define (services->sxml services)
          ;; Return the SXML 'includedir' clauses for DIRS.
          `(busconfig
            ,@(append-map (lambda (dir)
                            `((includedir
                               ,(string-append dir "/etc/dbus-1/system.d"))
                              (servicedir         ;for '.service' files
                               ,(string-append dir "/share/dbus-1/services"))
                              (servicedir       ;likewise, for auto-activation
                               ,(string-append
                                 dir
                                 "/share/dbus-1/system-services"))))
                          services)))

        (mkdir #$output)
        (copy-file (string-append #$dbus "/etc/dbus-1/system.conf")
                   (string-append #$output "/system.conf"))

        ;; The default 'system.conf' has an <includedir> clause for
        ;; 'system.d', so create it.
        (mkdir (string-append #$output "/system.d"))

        ;; 'system-local.conf' is automatically included by the default
        ;; 'system.conf', so this is where we stuff our own things.
        (call-with-output-file (string-append #$output "/system-local.conf")
          (lambda (port)
            (sxml->xml (services->sxml (list #$@services))
                       port)))))

  (computed-file "dbus-configuration" build))

(define %dbus-accounts
  ;; Accounts used by the system bus.
  (list (user-group (name "messagebus") (system? #t))
        (user-account
         (name "messagebus")
         (group "messagebus")
         (system? #t)
         (comment "D-Bus system bus user")
         (home-directory "/var/run/dbus")
         (shell #~(string-append #$shadow "/sbin/nologin")))))

(define (dbus-activation config)
  "Return an activation gexp for D-Bus using @var{config}."
  #~(begin
      (use-modules (guix build utils))

      (mkdir-p "/var/run/dbus")

      (let ((user (getpwnam "messagebus")))
        (chown "/var/run/dbus"
               (passwd:uid user) (passwd:gid user)))

      (unless (file-exists? "/etc/machine-id")
        (format #t "creating /etc/machine-id...~%")
        (let ((prog (string-append #$(dbus-configuration-dbus config)
                                   "/bin/dbus-uuidgen")))
          ;; XXX: We can't use 'system' because the initrd's
          ;; guile system(3) only works when 'sh' is in $PATH.
          (let ((pid (primitive-fork)))
            (if (zero? pid)
                (call-with-output-file "/etc/machine-id"
                  (lambda (port)
                    (close-fdes 1)
                    (dup2 (port->fdes port) 1)
                    (execl prog)))
                (waitpid pid)))))))

(define dbus-dmd-service
  (match-lambda
    (($ <dbus-configuration> dbus services)
     (let ((conf (dbus-configuration-directory dbus services)))
       (list (dmd-service
              (documentation "Run the D-Bus system daemon.")
              (provision '(dbus-system))
              (requirement '(user-processes))
              (start #~(make-forkexec-constructor
                        (list (string-append #$dbus "/bin/dbus-daemon")
                              "--nofork"
                              (string-append "--config-file=" #$conf
                                             "/system.conf"))))
              (stop #~(make-kill-destructor))))))))

(define dbus-root-service-type
  (service-type (name 'dbus)
                (extensions
                 (list (service-extension dmd-root-service-type
                                          dbus-dmd-service)
                       (service-extension activation-service-type
                                          dbus-activation)
                       (service-extension account-service-type
                                          (const %dbus-accounts))))

                ;; Extensions consist of lists of packages (representing D-Bus
                ;; services) that we just concatenate.
                ;;
                ;; FIXME: We need 'dbus-daemon-launch-helper' to be
                ;; setuid-root for auto-activation to work.
                (compose concatenate)

                ;; The service's parameters field is extended by augmenting
                ;; its <dbus-configuration> 'services' field.
                (extend (lambda (config services)
                          (dbus-configuration
                           (inherit config)
                           (services
                            (append (dbus-configuration-services config)
                                    services)))))))

(define* (dbus-service #:key (dbus dbus) (services '()))
  "Return a service that runs the \"system bus\", using @var{dbus}, with
support for @var{services}.

@uref{http://dbus.freedesktop.org/, D-Bus} is an inter-process communication
facility.  Its system bus is used to allow system services to communicate and
be notified of system-wide events.

@var{services} must be a list of packages that provide an
@file{etc/dbus-1/system.d} directory containing additional D-Bus configuration
and policy files.  For example, to allow avahi-daemon to use the system bus,
@var{services} must be equal to @code{(list avahi)}."
  (service dbus-root-service-type
           (dbus-configuration (dbus dbus)
                               (services services))))

;;; dbus.scm ends here