[Guile-commits] branch main updated: linker: Create a sparse file only when writing to a file port.

[Ludovic Courtès]

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civodul pushed a commit to branch main
in repository guile.

The following commit(s) were added to refs/heads/main by this push:
     new 112b617f5 linker: Create a sparse file only when writing to a file 
port.
112b617f5 is described below

commit 112b617f5921c67b4b2c45aae39f54cccd34d7ef
Author: Ludovic Courtès <ludo@gnu.org>
AuthorDate: Tue Apr 16 00:34:01 2024 +0200

    linker: Create a sparse file only when writing to a file port.
    
    Fixes a regression introduced in
    4a0c2433d97be9d995b3be74d90bc074d8efb5a7: the strategy wouldn’t work
    when writing to, say, a bytevector output port.
    
    * module/system/vm/linker.scm (link-elf)[write-padding]: Reintroduce
    loop for when PORT is not a file port.  Remove first argument.
---
 module/system/vm/linker.scm | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/module/system/vm/linker.scm b/module/system/vm/linker.scm
index 952e85c30..7f3a625a1 100644
--- a/module/system/vm/linker.scm
+++ b/module/system/vm/linker.scm
@@ -769,10 +769,21 @@ Returns a bytevector."
            objects)
           bv)
         (lambda (port)
-          (define (write-padding port size)
-            ;; Write SIZE bytes of padding to PORT.  Use 'seek' to
-            ;; create a sparse file.
-            (seek port size SEEK_CUR))
+          (define write-padding
+            ;; Write SIZE bytes of padding to PORT.
+            (if (file-port? port)
+                (lambda (size)
+                  ;; Use 'seek' to create a sparse file.
+                  (seek port size SEEK_CUR))
+                (let ((blank (make-bytevector 4096 0)))
+                  (lambda (size)
+                    ;; Write SIZE zeros.
+                    (let loop ((size size))
+                      (unless (zero? size)
+                        (let ((count (min size
+                                          (bytevector-length blank))))
+                          (put-bytevector port blank 0 count)
+                          (loop (- size count)))))))))
 
           (define (compute-padding objects)
             ;; Return the list of padding in between OBJECTS--the list
@@ -796,7 +807,7 @@ Returns a bytevector."
           (for-each
            (lambda (object padding)
              (let ((bv (make-bytevector (linker-object-size object) 0)))
-               (write-padding port padding)
+               (write-padding padding)
                (write-linker-object bv object symtab endianness)
                (put-bytevector port bv)))
            objects