activation: Don't create unneeded "/var/guix/gcroots/etc-directory".

* gnu/build/activation.scm (activate-etc): Don't create
  "/var/guix/gcroots/etc-directory".

activation: Set the firmware search path.

* gnu/build/activation.scm (activate-firmware): New procedure.
* gnu/system.scm (<operating-system>)[firmware]: New field.
  (directory-union): New procedure.
  (%base-firmware): New variable.
  (operating-system-activation-script): Use 'directory-union', and call
  'activate-firmware'.
* doc/guix.texi (operating-system Reference): Document 'firmware'.

system: Allow Linux-libre to find our 'modprobe' command.

Fixes <http://bugs.gnu.org/18525>.
Reported by Mark H Weaver <mhw@netris.org>.

* gnu/build/activation.scm (activate-modprobe): New procedure.
* gnu/system.scm (modprobe-wrapper): New procedure.
  (operating-system-activation-script): Use both.

activation: Ensure existing user accounts have the right settings.

* gnu/build/activation.scm (modify-user, ensure-user): New procedures.
  (activate-users+groups): Systematically call 'ensure-user'.

Merge branch 'master' into core-updates

Conflicts:
	gnu-system.am

activation: Honor $GUIX_NEW_SYSTEM for use by 'guix system reconfigure'.

* gnu/build/activation.scm (activate-current-system): Honor
  $GUIX_NEW_SYSTEM by default.
* guix/scripts/system.scm (switch-to-system): Set $GUIX_NEW_SYSTEM
  before loading SCRIPT.

Merge branch 'master' into core-updates

Conflicts:
	gnu/packages/image.scm

activation: Set the permissions of /etc/sudoers to 440.

* gnu/build/activation.scm (activate-etc): Move 'rm-f' to a local
  'define'.  When TARGET is "sudoers", make it 440.

activation: Make the /bin/sh symlink at activation time.

* gnu/build/install.scm (directives): Remove "/bin/sh".
* gnu/build/activation.scm (activate-/bin/sh): New procedure.
* gnu/system.scm (operating-system-activation-script): Use it.

activation: Make sure /etc/sudoers & co. are regular files.

Before that, 'sudo' would exit with:

  sudo: /etc/sudoers is not a regular file
  sudo: no valid sudoers sources found, quitting

* gnu/build/activation.scm (activate-etc): Check if SOURCE matches
  'file-is-directory?'.  If not, use 'copy-file' instead of 'symlink'.

activation: Remove outdated comment.

* gnu/build/activation.scm (activate-etc): Remove outdated comment.

activation: Factorize the link-or-copy trick.

* gnu/build/activation.scm (link-or-copy): New procedure.
  (activate-setuid-programs): Use it.

Merge branch 'master' into core-updates

Merge branch 'master' into core-updates

system: Add the 'system?' field for user groups.

Suggested by Mark H. Weaver.

* gnu/system/shadow.scm (<user-group>)[system?]: New field.
  (%base-groups): Introduce 'system-group' macro, and use it.
* gnu/system.scm (user-group->gexp): Pass the 'system?' field.
* guix/build/activation.scm (add-group): Add #:system? and honor it.
  (activate-users+groups): Handle the 'system?' field.
* gnu/system/file-systems.scm (%tty-gid): Choose an ID below 1000.
* doc/guix.texi (User Accounts): Document the 'system?' field.

system: Add a 'system?' field to user accounts.

* gnu/system/shadow.scm (<user-account>)[system?]: New field.
* gnu/system.scm (user-account->gexp): Add it.
* guix/build/activation.scm (add-user): Add #:system? parameter and
  honor it.
  (activate-users+groups): Handle the 'system?' part of user tuples.
  Pass it to 'add-user'.  Don't create PROFILE-DIR when SYSTEM? is
  true.
* gnu/services/dbus.scm (dbus-service): Add 'system?' field for
  "messagebus" account.
* gnu/services/base.scm (guix-build-accounts): Likewise.
* gnu/services/avahi.scm (avahi-service): Likewise.

activation: Preserve /etc/groups upon reboots.

This is a followup to e2fcc23.  The /etc/group file would be cleared
when booting.

* guix/build/activation.scm (activate-users+groups)[touch]: Rewrite so
  it does not wipe out FILE's contents.

Merge branch 'master' into core-updates

activation: Only create groups that do not exist yet.

Before that the effect would be to re-create groups at each boot, and
thus remove any members of the groups.

* guix/build/activation.scm (activate-users+groups): Call 'add-group'
  only when (getgrname name) fails.

Merge branch 'master' into core-updates