guix-devel/gnu/system/linux.scm

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;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2013 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 system linux)
#:use-module (guix store)
#:use-module (guix records)
#:use-module (guix derivations)
#:use-module (guix monads)
#:use-module (ice-9 match)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-26)
#:use-module ((guix utils) #:select (%current-system))
#:export (pam-service
pam-entry
pam-services->directory
%pam-other-services
unix-pam-service))
;;; Commentary:
;;;
;;; Configuration of Linux-related things, including pluggable authentication
;;; modules (PAM).
;;;
;;; Code:
;; PAM services (see
;; <http://www.linux-pam.org/Linux-PAM-html/sag-configuration-file.html>.)
(define-record-type* <pam-service> pam-service
make-pam-service
pam-service?
(name pam-service-name) ; string
;; The four "management groups".
(account pam-service-account ; list of <pam-entry>
(default '()))
(auth pam-service-auth
(default '()))
(password pam-service-password
(default '()))
(session pam-service-session
(default '())))
(define-record-type* <pam-entry> pam-entry
make-pam-entry
pam-entry?
(control pam-entry-control) ; string
(module pam-entry-module) ; file name
(arguments pam-entry-arguments ; list of strings
(default '())))
(define (pam-service->configuration service)
"Return the configuration string for SERVICE, to be dumped in
/etc/pam.d/NAME, where NAME is the name of SERVICE."
(define (entry->string type entry)
(match entry
(($ <pam-entry> control module (arguments ...))
(string-append type " "
control " " module " "
(string-join arguments)
"\n"))))
(match service
(($ <pam-service> name account auth password session)
(string-concatenate
(append (map (cut entry->string "account" <>) account)
(map (cut entry->string "auth" <>) auth)
(map (cut entry->string "password" <>) password)
(map (cut entry->string "session" <>) session))))))
(define (pam-services->directory services)
"Return the derivation to build the configuration directory to be used as
/etc/pam.d for SERVICES."
(mlet %store-monad
((names -> (map pam-service-name services))
(files (mapm %store-monad
(match-lambda
((and service ($ <pam-service> name))
(let ((config (pam-service->configuration service)))
(text-file (string-append name ".pam") config))))
;; XXX: Eventually, SERVICES may be a list of monadic
;; values instead of plain values.
(map return services))))
(define builder
'(begin
(use-modules (ice-9 match))
(let ((out (assoc-ref %outputs "out")))
(mkdir out)
(for-each (match-lambda
((name . file)
(symlink file (string-append out "/" name))))
%build-inputs)
#t)))
(derivation-expression "pam.d" (%current-system) builder (zip names files))))
(define %pam-other-services
;; The "other" PAM configuration, which denies everything (see
;; <http://www.linux-pam.org/Linux-PAM-html/sag-configuration-example.html>.)
(let ((deny (pam-entry
(control "required")
(module "pam_deny.so"))))
(pam-service
(name "other")
(account (list deny))
(auth (list deny))
(password (list deny))
(session (list deny)))))
(define unix-pam-service
(let ((unix (pam-entry
(control "required")
(module "pam_unix.so"))))
(lambda* (name #:key allow-empty-passwords? motd)
"Return a standard Unix-style PAM service for NAME. When
ALLOW-EMPTY-PASSWORDS? is true, allow empty passwords. When MOTD is true, it
should be the name of a file used as the message-of-the-day."
;; See <http://www.linux-pam.org/Linux-PAM-html/sag-configuration-example.html>.
(let ((name* name))
(pam-service
(name name*)
(account (list unix))
(auth (list (if allow-empty-passwords?
(pam-entry
(control "required")
(module "pam_unix.so")
(arguments '("nullok")))
unix)))
(password (list unix))
(session (if motd
(list unix
(pam-entry
(control "optional")
(module "pam_motd.so")
(arguments (list (string-append "motd=" motd)))))
(list unix))))))))
;;; linux.scm ends here