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-rw-r--r--gnu/system/shadow.scm42
1 files changed, 42 insertions, 0 deletions
diff --git a/gnu/system/shadow.scm b/gnu/system/shadow.scm
index a69339bc07..47557191f8 100644
--- a/gnu/system/shadow.scm
+++ b/gnu/system/shadow.scm
@@ -20,6 +20,7 @@
;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
(define-module (gnu system shadow)
+ #:use-module ((guix diagnostics) #:select (formatted-message))
#:use-module (guix records)
#:use-module (guix gexp)
#:use-module (guix store)
@@ -34,6 +35,7 @@
#:use-module ((gnu packages admin)
#:select (shadow))
#:use-module (gnu packages bash)
+ #:use-module (ice-9 match)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-26)
#:use-module (srfi srfi-34)
@@ -222,6 +224,44 @@ for a colorful Guile experience.\\n\\n\"))))\n"))
(rename-file ".nanorc" ".config/nano/nanorc"))
#t))))
+(define (find-duplicates list)
+ "Find duplicate entries in @var{list}.
+Two entries are considered duplicates, if they are @code{equal?} to each other.
+This implementation is made asymptotically faster than @code{delete-duplicates}
+through the internal use of hash tables."
+ (let loop ((list list)
+ ;; We actually modify table in-place, but still allocate it here
+ ;; so that we only need one level of indentation.
+ (table (make-hash-table)))
+ (match list
+ (()
+ (hash-fold (lambda (key value seed)
+ (if (> value 1)
+ (cons key seed)
+ seed))
+ '()
+ table))
+ ((first . rest)
+ (hash-set! table first
+ (1+ (hash-ref table first 0)))
+ (loop rest table)))))
+
+(define (assert-unique-account-names users)
+ (match (find-duplicates (map user-account-name users))
+ (() *unspecified*)
+ (duplicates
+ (warning
+ (G_ "the following accounts appear more than once:~{ ~a~}")
+ duplicates))))
+
+(define (assert-unique-group-names groups)
+ (match (find-duplicates (map user-group-name groups))
+ (() *unspecified*)
+ (duplicates
+ (warning
+ (G_ "the following groups appear more than once:~{ ~a~}")
+ duplicates))))
+
(define (assert-valid-users/groups users groups)
"Raise an error if USERS refer to groups not listed in GROUPS."
(let ((groups (list->set (map user-group-name groups))))
@@ -292,6 +332,8 @@ group."
(define group-specs
(map user-group->gexp groups))
+ (assert-unique-account-names accounts)
+ (assert-unique-group-names groups)
(assert-valid-users/groups accounts groups)
;; Add users and user groups.