system: Rename 'sudoers' into 'sudoers-file'.

* gnu/system.scm (<operating-system>): Rename record field.
  (etc-directory): Rename argument.
  (operating-system-etc-directory): Adjust accordingly.
* doc/guix.texi (operating-system Reference): Likewise.

system: 'hosts-file' is now a file-like object.

Partly fixes <http://bugs.gnu.org/20720>.
Reported by Alex Kost <alezost@gmail.com>.

* gnu/system.scm (default-/etc/hosts): Change 'text-file' to 'plain-file'.
  (maybe-file->monadic): New procedure.
  (operating-system-etc-directory): Use it.
* doc/guix.texi (operating-system Reference, Networking Services): Adjust
  accordingly.

system: 'sudoers' is now a file-like object.

Partly fixes <http://bugs.gnu.org/20720>
Reported by Alex Kost <alezost@gmail.com>.

* gnu/system.scm (etc-directory): Change default #:sudoers value to a
  'plain-file'.  Don't bind it.  Remove #~#$.
  (maybe-string->file): New procedure.
  (operating-system-etc-directory): Use it.
  (%sudoers-specification): Use 'plain-file'.
* doc/guix.texi (operating-system Reference): Adjust accordingly.

system: Define '%base-user-accounts'.

* gnu/system/shadow.scm (%base-user-accounts): New variable.
* gnu/system.scm (<operating-system>)[users]: Use it as the default value.
* gnu/system/examples/bare-bones.tmpl (users): Use it.
* gnu/system/examples/desktop.tmpl (users): Likewise.
* doc/guix.texi (operating-system Reference, User Accounts): Adjust
  accordingly.

system: Make sure user accounts refer to existing groups.

Fixes <http://bugs.gnu.org/20646>.
Reported by David Thompson <davet@gnu.org>.

* gnu/system/shadow.scm (assert-valid-users/groups): New procedure
* gnu/system.scm (operating-system-activation-script): Use it.
* tests/guix-system.sh (make_user_config): New function.
  Add 3 tests using it.
* po/guix/POTFILES.in: Add gnu/system/shadow.scm.

Merge branch 'master' into gtk-rebuild

Conflicts:
	gnu/packages/gtk.scm

system: Use "." instead of "source" in /etc/profile.

* gnu/system.scm (etc-directory)[profile]: Use "." instead of "source",
  the latter being Bash-specific.

system: Check whether ~/.guix-profile/etc/profile exists.

* gnu/system.scm (etc-directory)[profile]: Check for
  ~/.guix-profile/etc/profile rather than just ~/.guix-profile.

system: /etc/profile sources each profile's /etc/profile.

Partly fixes <http://bugs.gnu.org/20255>.
Reported by 宋文武 <iyzsong@gmail.com>.

* gnu/system.scm (etc-directory)[profile]: Source
  /run/current-system/profile/etc/profile and
  $HOME/.guix-profile/etc/profile when available.  Move definitions of
  SSL_CERT_DIR, SSL_CERT_FILE, and GIT_SSL_CAINFO before that.

Merge branch 'master' into core-updates

Conflicts:
	gnu-system.am
	gnu/packages/gstreamer.scm

system: Populate /etc/shells with the list of all the shells in use.

Reported by Andy Wingo <wingo@pobox.com>.

* gnu/system.scm (user-shells, shells-file): New procedures.
  (etc-directory): Add #:shell parameter.  Use 'shells-file' instead of
  'text-file'.
  (operating-system-etc-directory): Call 'user-shells' and pass #:shells
  to 'etc-directory'.

Merge branch 'master' into core-updates

system: Allow users to PTRACE_ATTACH to their own processes.

* gnu/build/activation.scm (activate-ptrace-attach): New procedure.
* gnu/system.scm (operating-system-activation-script): Use it.

system: Clean /tmp and /var/run during early boot.

* gnu/system.scm (operating-system-boot-script): Clean out /tmp and
  /var/run before activating the system.

Merge branch 'master' into core-updates

system: Take kernel modules from the user-specified kernel.

* gnu/system/linux-initrd.scm (base-initrd): Add #:linux option to
  specify the linux kernel to use.
* gnu/system/vm.scm (expression->derivation-in-linux-vm): Propagate
  #:linux to base-initrd.
* gnu/system.scm (operating-system-initrd-file): Pass #:linux to
  'make-initrd'.

Co-authored-by: Ludovic Courtès <ludo@gnu.org>

Merge branch 'master' into core-updates

system: Add /etc/bashrc that loads bash-completion when available.

* gnu/system.scm (etc-directory)[profile]: Conditionally source
  /etc/bashrc.
  [bashrc]: New file.  Source bash_completion.sh when available.

system: Add fish, tcsh, and zsh to /etc/shells.

* gnu/system.scm (etc-directory)[shells]: Add fish, tcsh, and zsh file
  names to /etc/shells.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

system: Remove duplicated line from export.

* gnu/system.scm (gnu system): Remove duplicate in
  exported names list.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>