1 files changed, 38 insertions, 3 deletions
diff --git a/guix/utils.scm b/guix/utils.scm
index d7b197fa44..812617dd61 100644
--- a/guix/utils.scm
+++ b/guix/utils.scm
@@ -35,8 +35,10 @@
   #:use-module (rnrs io ports)                    ;need 'port-position' etc.
   #:use-module ((rnrs bytevectors) #:select (bytevector-u8-set!))
   #:use-module (guix memoization)
-  #:use-module ((guix build utils) #:select (dump-port mkdir-p delete-file-recursively))
-  #:use-module ((guix build syscalls) #:select (mkdtemp! fdatasync))
+  #:use-module ((guix build utils)
+                #:select (dump-port mkdir-p delete-file-recursively
+                                    executable-file?))
+  #:use-module ((guix build syscalls) #:select (mkdtemp! fdatasync scandir*))
   #:use-module (ice-9 format)
   #:use-module (ice-9 regex)
   #:use-module (ice-9 match)
@@ -109,7 +111,8 @@
             call-with-decompressed-port
             compressed-output-port
             call-with-compressed-output-port
-            canonical-newline-port))
+            canonical-newline-port
+            reset-timestamps))
 
 
 ;;;
@@ -843,6 +846,38 @@ a location object."
   fix-hint?
   (hint condition-fix-hint))                      ;string
 
+(define* (reset-timestamps file #:key preserve-permissions?)
+  "Reset the modification time on FILE and on all the files it contains, if
+it's a directory.  Canonicalize file permissions unless PRESERVE-PERMISSIONS?
+is true."
+  ;; Note: We're resetting to one second after the Epoch like 'guix-daemon'
+  ;; has always done.
+  (let loop ((file file)
+             (type (stat:type (lstat file))))
+    (case type
+      ((directory)
+       (unless preserve-permissions?
+         (chmod file #o555))
+       (utime file 1 1 0 0)
+       (let ((parent file))
+         (for-each (match-lambda
+                     (("." . _) #f)
+                     ((".." . _) #f)
+                     ((file . properties)
+                      (let ((file (string-append parent "/" file)))
+                        (loop file
+                              (match (assoc-ref properties 'type)
+                                ((or 'unknown #f)
+                                 (stat:type (lstat file)))
+                                (type type))))))
+                   (scandir* parent))))
+      ((symlink)
+       (utime file 1 1 0 0 AT_SYMLINK_NOFOLLOW))
+      (else
+       (unless preserve-permissions?
+         (chmod file (if (executable-file? file) #o555 #o444)))
+       (utime file 1 1 0 0)))))
+
 ;;; Local Variables:
 ;;; eval: (put 'call-with-progress-reporter 'scheme-indent-function 1)
 ;;; End: