[bug#52454] [PATCH 1/4] syscalls: Add 'lchown'.

[Brice Waegeneire <brice@waegenei.re>]

* guix/build/syscalls.scm (lchown): New procedure.
---
 guix/build/syscalls.scm | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/guix/build/syscalls.scm b/guix/build/syscalls.scm
index 63bd017d1d..1c432507c3 100644
--- a/guix/build/syscalls.scm
+++ b/guix/build/syscalls.scm
@@ -8,6 +8,7 @@
 ;;; Copyright © 2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
 ;;; Copyright © 2021 Chris Marusich <cmmarusich@gmail.com>
 ;;; Copyright © 2021 Tobias Geerinckx-Rice <me@tobias.gr>
+;;; Copyright © 2021 Brice Waegeneire <brice@waegenei.re>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -118,6 +119,7 @@ (define-module (guix build syscalls)
             scandir*
             getxattr
             setxattr
+            lchown
 
             fcntl-flock
             lock-file
@@ -1275,6 +1277,20 @@ (define* (scandir* name #:optional
       (lambda ()
         (closedir* directory)))))
 
+(define lchown
+  (let ((proc (syscall->procedure int "lchown" (list '* int int))))
+    (lambda (file owner group)
+      "As 'chown', change the ownership and group of the file referred to by
+FILE to the integer values OWNER and GROUP but doesn't dereference symbolic
+links.  Unlike 'chown' this doesn't support port or integer file descriptor
+via 'fchown'."
+      (let-values (((ret err)
+                    (proc (string->pointer file) owner group)))
+        (unless (zero? ret)
+          (throw 'system-error "lchown" "~S: ~A"
+                 (list file (strerror err))
+                 (list err)))))))
+
 \f
 ;;;
 ;;; Advisory file locking.
-- 
2.34.0