services: Add 'session-environment-service'.

* gnu/services/base.scm (session-environment-service): New procedure.
(session-environment-service-type): New variable.
(environment-variables->environment-file): New procedure.

services: Add pkexec to setuid programs.

* gnu/services/desktop.scm (polkit-setuid-programs): Add pkexec to
  list of setuid programs.

services: tor: Store private data under /var/lib/tor.

* gnu/services/networking.scm (tor-configuration->torrc): Add
'DataDirectory' clause.  Change 'HiddenServiceDir' to
/var/lib/tor/hidden-services/NAME.
(tor-hidden-service-activation): Create /var/lib/tor.
(tor-hidden-service): Adjust docstring.
* doc/guix.texi (Networking Services): Adjust accordingly.

services: tor: Write to syslog.

* gnu/services/networking.scm (tor-configuration->torrc): Add "Log
notice syslog".
(tor-dmd-service): Add 'syslogd' to 'requirement'.

services: Add 'tor-hidden-service'.

* gnu/services/networking.scm (<tor-configuration>, <hidden-service>):
New record types.
(tor-configuration->torrc): New procedure.
(tor-dmd-service): Use it.
(tor-hidden-service-activation): New procedure.
(tor-service-type)[extensions]: Extend ACTIVATION-SERVICE-TYPE.
[compose, extend]: New fields.
(tor-service): Use 'tor-configuration'.
(tor-hidden-service-type): New variable.
(tor-hidden-service): New procedure.

services: lsh: Correctly handle #:interfaces option.

* gnu/services/ssh.scm (lsh-dmd-service)[lsh-command]: Pass a series of
--interface flags instead of the nonexistent --interfaces option.

services: Add network-manager-service.

* gnu/services/networking.scm (network-manager-service): New procedure.
(network-manager-service-type, %network-manager-activation): New variables.
(network-manager-dmd-service): New procedure.

services: xorg: Export additional symbols.

'slim-configuration' and 'slim-service-type' are needed if one wishes to
use 'modify-services' on a service list that includes the slim service.

* gnu/services/xorg.scm: Export 'slim-configuration' and
  'slim-service-type'.

services: dmd: Spawn a REPL upon failure to load a service definition.

Fixes <http://bugs.gnu.org/19779>.
Reported by Mark H Weaver <mhw@netris.org>.

* gnu/services/dmd.scm (dmd-configuration-file)[config]: Wrap
'primitive-load' calls in 'call-with-error-handling'.

services: dmd: Strip the default list of modules.

* gnu/services/dmd.scm (%default-imported-modules): Remove (gnu build
file-systems).
(%default-modules): Likewise, and remove (ice-9 ftw).
* gnu/services/base.scm (file-system-service-type): Add 'modules' and
'imported-modules' fields.

services: dmd: Add 'modules' and 'imported-modules' fields.

* gnu/services/dmd.scm (%default-imported-modules, %default-modules):
New variables.
* gnu/services/dmd.scm (<dmd-service>)[modules, imported-modules]: New
field.
* gnu/services/dmd.scm (dmd-service-file-name, dmd-service-file): New
procedures.
(dmd-configuration-file)[modules]: Compute based on the
'imported-modules' field of SERVICES.
(dmd-configuration-file): Remove 'use-modules' form.  Use
'dmd-service-file', and call 'primitive-load' on each file.
* doc/guix.texi (dmd Services): Document the new fields.

services: dmd: Error out upon unmet dmd requirements.

* gnu/services/dmd.scm (assert-no-duplicates): Rename to...
(assert-valid-graph): ... this.
[provisions]: New variable.
[assert-satisfied-requirements]: New procedure.
Use it.
* tests/guix-system.sh: Add test with unmet dmd requirements.

gnu: services: Fix typo in gpm-dmd-service.

* gnu/services/base.scm (gpm-dmd-service): s/dmd/gpm/

services: Add udev-rule procedure.

* gnu/services/base.scm (udev-rule): New procedure.
(kvm-udev-rule): Rewrite as variable in terms of udev-rule.

services: Export udev-configuration procedures.

* gnu/services/base.scm (udev-configuration, udev-configuration?,
  udev-configuration-rules): Export.

services: Add 'gpm-service'.

* gnu/services/base.scm (<gpm-configuration>): New record type.
  (gpm-dmd-service): New procedure.
  (gpm-service-type): New variable.
  (gpm-service): New procedure.
* doc/guix.texi (Base Services): Document it.

system: Rename (gnu system linux) to (gnu system pam).

* gnu/system/linux.scm: Rename to...
* gnu/system/pam.scm: ... this.
* gnu-system.am (GNU_SYSTEM_MODULES): Adjust accordingly.
* gnu.scm, gnu/services/base.scm, gnu/services/desktop.scm,
  gnu/services/networking.scm, gnu/services/ssh.scm,
  gnu/services/xorg.scm, gnu/system.scm, gnu/system/vm.scm: Likewise.

services: Add 'guix-publish-service'.

* gnu/services/base.scm (<guix-publish-configuration>): New record
  type.
  (guix-publish-dmd-service): New procedure.
  (%guix-publish-accounts, guix-publish-service-type): New variables.
  (guix-publish-service): New procedure.
* doc/guix.texi (Invoking guix publish): Add xref to
  'guix-publish-service' anchor.
  (Base Services): Document 'guix-publish-service'.

services: udisks: Add UDisks to the system profile.

* gnu/services/desktop.scm (udisks-service-type): Extend
  PROFILE-SERVICE-TYPE.

services: avahi: Add Avahi to the system profile.

* gnu/services/avahi.scm (avahi-service-type): Extend
  PROFILE-SERVICE-TYPE.
  (avahi-service): Adjust docstring.
* doc/guix.texi (Networking Services): Adjust accordingly.
* gnu/system/examples/desktop.tmpl (packages): Remove AVAHI.