From 61f691fdfb4846e123e6423ee192142a35bd114d Mon Sep 17 00:00:00 2001
From: Maxim Cournoyer <maxim.cournoyer@gmail.com>
Date: Thu, 23 Feb 2023 23:37:32 -0500
Subject: [PATCH] cpio: Properly handle Unicode characters in file names.

Fixes <https://issues.guix.gnu.org/61722>.

* guix/cpio.scm (file->cpio-header): Compute the file name length in bytes rather than in
characters.
(file->cpio-header*, special-file->cpio-header*): Likewise.
(write-cpio-archive): Likewise, and write the file name as UTF-8 bytes, not
textually, to avoid encoding it as ISO-8859-1.
---
 guix/cpio.scm | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/guix/cpio.scm b/guix/cpio.scm
index d4a7d5f1e0..876f61ea3c 100644
--- a/guix/cpio.scm
+++ b/guix/cpio.scm
@@ -170,7 +170,7 @@ (define* (file->cpio-header file #:optional (file-name file)
                       #:size (stat:size st)
                       #:dev (stat:dev st)
                       #:rdev (stat:rdev st)
-                      #:name-size (string-length file-name))))
+                      #:name-size (string-utf8-length file-name))))
 
 (define* (file->cpio-header* file
                              #:optional (file-name file)
@@ -182,7 +182,7 @@ (define* (file->cpio-header* file
     (make-cpio-header #:mode (stat:mode st)
                       #:nlink (stat:nlink st)
                       #:size (stat:size st)
-                      #:name-size (string-length file-name))))
+                      #:name-size (string-utf8-length file-name))))
 
 (define* (special-file->cpio-header* file
                                      device-type
@@ -201,7 +201,7 @@ (define* (special-file->cpio-header* file
                                     permission-bits)
                     #:nlink 1
                     #:rdev (device-number device-major device-minor)
-                    #:name-size (string-length file-name)))
+                    #:name-size (string-utf8-length file-name)))
 
 (define %trailer
   "TRAILER!!!")
@@ -237,7 +237,7 @@ (define (dump-file file)
 
       ;; We're padding the header + following file name + trailing zero, and
       ;; the header is 110 byte long.
-      (write-padding (+ 110 1 (string-length file)) port)
+      (write-padding (+ 110 (string-utf8-length file) 1) port)
 
       (case (mode->type (cpio-header-mode header))
         ((regular)
@@ -246,7 +246,7 @@ (define (dump-file file)
              (dump-port input port))))
         ((symlink)
          (let ((target (readlink file)))
-           (put-string port target)))
+           (put-bytevector port (string->utf8 target))))
         ((directory)
          #t)
         ((block-special)