Revert "Use mmap for the elf parser, reducing memory usage."

This reverts commit 2c1fe0df11ae0f66392b8abb6f62430d79305538.

7 files changed, 164 insertions, 147 deletions

diff --git a/gnu/packages/gnuzilla.scm b/gnu/packages/gnuzilla.scm
index d24797b85a0..259f9a6fc6e 100644
--- a/gnu/packages/gnuzilla.scm
+++ b/gnu/packages/gnuzilla.scm
@@ -996,10 +996,16 @@ preferences/advanced-scripts.dtd"
                  (search-input-file inputs "lib/libavcodec.so")))))
           (add-after 'fix-ffmpeg-runtime-linker 'build-sandbox-whitelist
             (lambda* (#:key inputs #:allow-other-keys)
+              (define (runpath-of lib)
+                (call-with-input-file lib
+                  (compose elf-dynamic-info-runpath
+                           elf-dynamic-info
+                           parse-elf
+                           get-bytevector-all)))
               (define (runpaths-of-input label)
                 (let* ((dir (string-append (assoc-ref inputs label) "/lib"))
                        (libs (find-files dir "\\.so$")))
-                  (append-map file-runpath libs)))
+                  (append-map runpath-of libs)))
               ;; Populate the sandbox read-path whitelist as needed by ffmpeg.
               (let* ((whitelist
                       (map (cut string-append <> "/")
diff --git a/gnu/packages/librewolf.scm b/gnu/packages/librewolf.scm
index 6c852d7f1c2..f8800b19252 100644
--- a/gnu/packages/librewolf.scm
+++ b/gnu/packages/librewolf.scm
@@ -530,11 +530,15 @@
               ;; The following two functions are from Guix's icecat package in
               ;; (gnu packages gnuzilla).  See commit
               ;; b7a0935420ee630a29b7e5ac73a32ba1eb24f00b.
+              (define (runpath-of lib)
+                (call-with-input-file lib
+                  (compose elf-dynamic-info-runpath elf-dynamic-info
+                           parse-elf get-bytevector-all)))
               (define (runpaths-of-input label)
                 (let* ((dir (string-append (assoc-ref inputs label)
                                            "/lib"))
                        (libs (find-files dir "\\.so$")))
-                  (append-map file-runpath libs)))
+                  (append-map runpath-of libs)))
               (let* ((out (assoc-ref outputs "out"))
                      (lib (string-append out "/lib"))
                      (libs (map
diff --git a/guix/build/debug-link.scm b/guix/build/debug-link.scm
index 7a74e6001b7..80941df2fc7 100644
--- a/guix/build/debug-link.scm
+++ b/guix/build/debug-link.scm
@@ -1,6 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2018, 2023 Ludovic Courtès <ludo@gnu.org>
-;;; Copyright © 2025 Maxim Cournoyer <maxim@guixotic.coop>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -19,7 +18,6 @@
 
 (define-module (guix build debug-link)
   #:use-module (guix elf)
-  #:use-module (guix build io)
   #:use-module ((guix build utils)
                 #:select (find-files elf-file? make-file-writable))
   #:use-module (rnrs bytevectors)
@@ -149,13 +147,16 @@ Return #f for both if ELF lacks a '.gnu_debuglink' section."
 (define (set-debuglink-crc file debug-file)
   "Compute the CRC of DEBUG-FILE and set it as the '.gnu_debuglink' CRC in
 FILE."
-  (let* ((bv (file->bytevector file #:protection (logior PROT_READ PROT_WRITE)))
-         (elf (parse-elf bv))
+  (let* ((elf    (parse-elf (call-with-input-file file get-bytevector-all)))
          (offset (elf-debuglink-crc-offset elf)))
-    (when offset
-      (let ((crc (call-with-input-file debug-file debuglink-crc32)))
-        (bytevector-u32-set! bv offset crc (elf-byte-order elf))
-        (munmap bv)))))
+    (and offset
+         (let* ((crc (call-with-input-file debug-file debuglink-crc32))
+                (bv  (make-bytevector 4)))
+           (bytevector-u32-set! bv 0 crc (elf-byte-order elf))
+           (let ((port (open file O_RDWR)))
+             (set-port-position! port offset)
+             (put-bytevector port bv)
+             (close-port port))))))
 
 
 ;;;
diff --git a/guix/build/gremlin.scm b/guix/build/gremlin.scm
index 2392a74a359..2a74d51dd91 100644
--- a/guix/build/gremlin.scm
+++ b/guix/build/gremlin.scm
@@ -1,6 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2015, 2018, 2020 Ludovic Courtès <ludo@gnu.org>
-;;; Copyright © 2025 Maxim Cournoyer <maxim@guixotic.coop>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -19,7 +18,6 @@
 
 (define-module (guix build gremlin)
   #:use-module (guix elf)
-  #:use-module (guix build io)
   #:use-module ((guix build utils) #:select (store-file-name?))
   #:use-module (ice-9 match)
   #:use-module (srfi srfi-1)
@@ -250,7 +248,9 @@ string table if the type is a string."
 (define (file-dynamic-info file)
   "Return the <elf-dynamic-info> record of FILE, or #f if FILE lacks dynamic
 info."
-  (elf-dynamic-info (parse-elf (file->bytevector file))))
+  (call-with-input-file file
+    (lambda (port)
+      (elf-dynamic-info (parse-elf (get-bytevector-all port))))))
 
 (define (file-runpath file)
   "Return the DT_RUNPATH dynamic entry of FILE as a list of strings, or #f if
@@ -362,7 +362,8 @@ exceeds total size~%"
                        (elf-segment-type segment))
                #f)))
 
-    (let* ((elf     (parse-elf (file->bytevector file)))
+    (let* ((elf     (call-with-input-file file
+                      (compose parse-elf get-bytevector-all)))
            (expand  (cute expand-origin <> (dirname file)))
            (dyninfo (elf-dynamic-info elf)))
       (when dyninfo
@@ -401,13 +402,12 @@ according to DT_NEEDED."
                         needed)))
             runpath))
 
-  (define bv (file->bytevector file #:protection
-                               (logior PROT_READ PROT_WRITE)))
+  (define port
+    (open-file file "r+b"))
 
-  (dynamic-wind
-    (const #t)
+  (catch #t
     (lambda ()
-      (let* ((elf (parse-elf bv))
+      (let* ((elf      (parse-elf (get-bytevector-all port)))
              (entries  (dynamic-entries elf (dynamic-link-segment elf)))
              (needed   (filter-map (lambda (entry)
                                      (and (= (dynamic-entry-type entry)
@@ -425,14 +425,15 @@ according to DT_NEEDED."
                   "~a: stripping RUNPATH to ~s (removed ~s)~%"
                   file new
                   (lset-difference string=? old new))
-          ;; Write to bytevector directly.
-          (let ((src (string->utf8 (string-append (string-join new ":")
-                                                  "\0"))))
-            (bytevector-copy! src 0 bv (dynamic-entry-offset runpath)
-                              (bytevector-length src))))
+          (seek port (dynamic-entry-offset runpath) SEEK_SET)
+          (put-bytevector port (string->utf8 (string-join new ":")))
+          (put-u8 port 0))
+        (close-port port)
         new))
-    (lambda ()
-      (munmap bv))))
+    (lambda (key . args)
+      (false-if-exception (close-port port))
+      (apply throw key args))))
+
 
 (define-condition-type &missing-runpath-error &elf-error
   missing-runpath-error?
@@ -446,18 +447,20 @@ according to DT_NEEDED."
   "Set the value of the DT_RUNPATH dynamic entry of FILE, which must name an
 ELF file, to PATH, a list of strings.  Raise a &missing-runpath-error or
 &runpath-too-long-error when appropriate."
-  (define bv (file->bytevector file #:protection
-                               (logior PROT_READ PROT_WRITE)))
-  (dynamic-wind
-    (const #t)
-    (lambda ()
-      (let* ((elf     (parse-elf bv))
+  (define (call-with-input+output-file file proc)
+    (let ((port (open-file file "r+b")))
+      (guard (c (#t (close-port port) (raise c)))
+        (proc port)
+        (close-port port))))
+
+  (call-with-input+output-file file
+    (lambda (port)
+      (let* ((elf     (parse-elf (get-bytevector-all port)))
              (entries (dynamic-entries elf (dynamic-link-segment elf)))
              (runpath (find (lambda (entry)
                               (= DT_RUNPATH (dynamic-entry-type entry)))
                             entries))
-             (path    (string->utf8 (string-append (string-join path ":")
-                                                   "\0"))))
+             (path    (string->utf8 (string-join path ":"))))
         (unless runpath
           (raise (condition (&missing-runpath-error (elf elf)
                                                     (file file)))))
@@ -470,7 +473,10 @@ ELF file, to PATH, a list of strings.  Raise a &missing-runpath-error or
           (raise (condition (&runpath-too-long-error (elf #f #;elf)
                                                      (file file)))))
 
-        (bytevector-copy! path 0 bv (dynamic-entry-offset runpath)
-                          (bytevector-length path))))
-    (lambda ()
-      (munmap bv))))
+        (seek port (dynamic-entry-offset runpath) SEEK_SET)
+        (put-bytevector port path)
+        (put-u8 port 0)))))
+
+;;; Local Variables:
+;;; eval: (put 'call-with-input+output-file 'scheme-indent-function 1)
+;;; End:
diff --git a/guix/scripts/pack.scm b/guix/scripts/pack.scm
index 432e846bf4f..a6a7babf595 100644
--- a/guix/scripts/pack.scm
+++ b/guix/scripts/pack.scm
@@ -5,7 +5,7 @@
 ;;; Copyright © 2018 Chris Marusich <cmmarusich@gmail.com>
 ;;; Copyright © 2018 Efraim Flashner <efraim@flashner.co.il>
 ;;; Copyright © 2020 Tobias Geerinckx-Rice <me@tobias.gr>
-;;; Copyright © 2020-2023, 2025 Maxim Cournoyer <maxim@guixotic.coop>
+;;; Copyright © 2020, 2021, 2022, 2023 Maxim Cournoyer <maxim@guixotic.coop>
 ;;; Copyright © 2020 Eric Bavier <bavier@posteo.net>
 ;;; Copyright © 2022 Alex Griffin <a@ajgrf.com>
 ;;; Copyright © 2023 Graham James Addis <graham@addis.org.uk>
@@ -1221,14 +1221,12 @@ libfakechroot.so and related ld.so machinery as a fallback."
 
   (define build
     (with-imported-modules (source-module-closure
-                            '((guix build io)
-                              (guix build utils)
+                            '((guix build utils)
                               (guix build union)
                               (guix build gremlin)
                               (guix elf)))
       #~(begin
-          (use-modules (guix build io)
-                       (guix build utils)
+          (use-modules (guix build utils)
                        ((guix build union) #:select (symlink-relative))
                        (guix elf)
                        (guix build gremlin)
@@ -1262,7 +1260,7 @@ libfakechroot.so and related ld.so machinery as a fallback."
             (match (find (lambda (segment)
                            (= (elf-segment-type segment) PT_INTERP))
                          (elf-segments elf))
-              (#f #f)                   ;maybe a .so
+              (#f #f)                             ;maybe a .so
               (segment
                (let ((bv (make-bytevector (- (elf-segment-memsz segment) 1))))
                  (bytevector-copy! (elf-bytes elf)
@@ -1282,7 +1280,8 @@ libfakechroot.so and related ld.so machinery as a fallback."
             #$(if fakechroot?
                   ;; TODO: Handle scripts by wrapping their interpreter.
                   #~(if (elf-file? program)
-                        (let* ((bv      (file->bytevector program))
+                        (let* ((bv      (call-with-input-file program
+                                          get-bytevector-all))
                                (elf     (parse-elf bv))
                                (interp  (elf-interpreter elf))
                                (gconv   (and interp
diff --git a/tests/debug-link.scm b/tests/debug-link.scm
index 7ccc054a5d9..a1ae4f141c0 100644
--- a/tests/debug-link.scm
+++ b/tests/debug-link.scm
@@ -1,6 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2018 Ludovic Courtès <ludo@gnu.org>
-;;; Copyright © 2025 Maxim Cournoyer <maxim@guixotic.coop>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -21,15 +20,12 @@
   #:use-module (guix elf)
   #:use-module (guix build utils)
   #:use-module (guix build debug-link)
-  #:use-module (guix build io)
   #:use-module (guix gexp)
-  #:use-module (guix modules)
   #:use-module (guix store)
   #:use-module (guix tests)
   #:use-module (guix monads)
   #:use-module (guix derivations)
   #:use-module (gnu packages bootstrap)
-  #:use-module ((gnu packages guile) #:select (guile-3.0))
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-26)
   #:use-module (srfi srfi-64)
@@ -44,12 +40,15 @@
     (_
      #f)))
 
+(define read-elf
+  (compose parse-elf get-bytevector-all))
+
 
 (test-begin "debug-link")
 
 (unless %guile-executable (test-skip 1))
-(test-assert "elf-debuglink, no .gnu_debuglink section"
-  (let ((elf (parse-elf (file->bytevector %guile-executable))))
+(test-assert "elf-debuglink"
+  (let ((elf (call-with-input-file %guile-executable read-elf)))
     (match (call-with-values (lambda () (elf-debuglink elf)) list)
       ((#f #f)                                    ;no '.gnu_debuglink' section
        (pk 'no-debuglink #t))
@@ -57,101 +56,95 @@
        (string-suffix? ".debug" file)))))
 
 ;; Since we need %BOOTSTRAP-GCC and co., we have to skip the following tests
-;; when networking is unreachable because we'd fail to download it.  Since
-;; using mmap to load ELF more efficiently, we also need the regular Guile
-;; package, as guile-bootstrap cannot resolve dynamic symbols.
-(with-external-store store
-  (unless (and (network-reachable?) store) (test-skip 1))
-  (test-assertm "elf-debuglink"
-      ;; Check whether we can compute the CRC just like objcopy, and whether we
-      ;; can retrieve it.
-      (let* ((code (plain-file "test.c" "int main () { return 42; }"))
-             (exp  (with-imported-modules (source-module-closure
-                                           '((guix build io)
-                                             (guix build utils)
-                                             (guix build debug-link)
-                                             (guix elf)))
-                     #~(begin
-                         (use-modules (guix build io)
-                                      (guix build utils)
-                                      (guix build debug-link)
-                                      (guix elf)
-                                      (rnrs io ports))
+;; when networking is unreachable because we'd fail to download it.
+(unless (network-reachable?) (test-skip 1))
+(test-assertm "elf-debuglink"
+  ;; Check whether we can compute the CRC just like objcopy, and whether we
+  ;; can retrieve it.
+  (let* ((code (plain-file "test.c" "int main () { return 42; }"))
+         (exp  (with-imported-modules '((guix build utils)
+                                        (guix build debug-link)
+                                        (guix elf))
+                 #~(begin
+                     (use-modules (guix build utils)
+                                  (guix build debug-link)
+                                  (guix elf)
+                                  (rnrs io ports))
 
-                         (define read-elf
-                           (compose parse-elf file->bytevector))
+                     (define read-elf
+                       (compose parse-elf get-bytevector-all))
 
-                         (setenv "PATH" (string-join '(#$%bootstrap-gcc
-                                                       #$%bootstrap-binutils)
-                                                     "/bin:" 'suffix))
-                         (invoke "gcc" "-O0" "-g" #$code "-o" "exe")
-                         (copy-file "exe" "exe.debug")
-                         (invoke "strip" "--only-keep-debug" "exe.debug")
-                         (invoke "strip" "--strip-debug" "exe")
-                         (invoke "objcopy" "--add-gnu-debuglink=exe.debug"
-                                 "exe")
-                         (call-with-values (lambda ()
-                                             (elf-debuglink (read-elf "exe")))
-                           (lambda (file crc)
-                             (call-with-output-file #$output
-                               (lambda (port)
-                                 (let ((expected (call-with-input-file "exe.debug"
-                                                   debuglink-crc32)))
-                                   (write (list file (= crc expected))
-                                          port))))))))))
-        (mlet* %store-monad ((drv (gexp->derivation "debuglink" exp))
-                             (x   (built-derivations (list drv))))
-          (call-with-input-file (derivation->output-path drv)
-            (lambda (port)
-              (return (match (read port)
-                        (("exe.debug" #t) #t)
-                        (x                (pk 'fail x #f)))))))))
+                     (setenv "PATH" (string-join '(#$%bootstrap-gcc
+                                                   #$%bootstrap-binutils)
+                                                 "/bin:" 'suffix))
+                     (invoke "gcc" "-O0" "-g" #$code "-o" "exe")
+                     (copy-file "exe" "exe.debug")
+                     (invoke "strip" "--only-keep-debug" "exe.debug")
+                     (invoke "strip" "--strip-debug" "exe")
+                     (invoke "objcopy" "--add-gnu-debuglink=exe.debug"
+                             "exe")
+                     (call-with-values (lambda ()
+                                         (elf-debuglink
+                                          (call-with-input-file "exe"
+                                            read-elf)))
+                       (lambda (file crc)
+                         (call-with-output-file #$output
+                           (lambda (port)
+                             (let ((expected (call-with-input-file "exe.debug"
+                                               debuglink-crc32)))
+                               (write (list file (= crc expected))
+                                      port))))))))))
+    (mlet* %store-monad ((drv (gexp->derivation "debuglink" exp))
+                         (x   (built-derivations (list drv))))
+      (call-with-input-file (derivation->output-path drv)
+        (lambda (port)
+          (return (match (read port)
+                    (("exe.debug" #t) #t)
+                    (x                (pk 'fail x #f)))))))))
 
-  (unless (and (network-reachable?) store) (test-skip 1))
-  (test-assertm "set-debuglink-crc"
-      ;; Check whether 'set-debuglink-crc' successfully updates the CRC.
-      (let* ((code  (plain-file "test.c" "int main () { return 42; }"))
-             (debug (plain-file "exe.debug" "a"))
-             (exp   (with-imported-modules (source-module-closure
-                                            '((guix build io)
-                                              (guix build utils)
-                                              (guix build debug-link)
-                                              (guix elf)))
-                      #~(begin
-                          (use-modules (guix build io)
-                                       (guix build utils)
-                                       (guix build debug-link)
-                                       (guix elf)
-                                       (rnrs io ports))
+(unless (network-reachable?) (test-skip 1))
+(test-assertm "set-debuglink-crc"
+  ;; Check whether 'set-debuglink-crc' successfully updates the CRC.
+  (let* ((code  (plain-file "test.c" "int main () { return 42; }"))
+         (debug (plain-file "exe.debug" "a"))
+         (exp   (with-imported-modules '((guix build utils)
+                                         (guix build debug-link)
+                                         (guix elf))
+                  #~(begin
+                      (use-modules (guix build utils)
+                                   (guix build debug-link)
+                                   (guix elf)
+                                   (rnrs io ports))
 
-                          (define read-elf
-                            (compose parse-elf file->bytevector))
+                      (define read-elf
+                        (compose parse-elf get-bytevector-all))
 
-                          (setenv "PATH" (string-join '(#$%bootstrap-gcc
-                                                        #$%bootstrap-binutils)
-                                                      "/bin:" 'suffix))
-                          (invoke "gcc" "-O0" "-g" #$code "-o" "exe")
-                          (copy-file "exe" "exe.debug")
-                          (invoke "strip" "--only-keep-debug" "exe.debug")
-                          (invoke "strip" "--strip-debug" "exe")
-                          (invoke "objcopy" "--add-gnu-debuglink=exe.debug"
-                                  "exe")
-                          (set-debuglink-crc "exe" #$debug)
-                          (call-with-values (lambda ()
-                                              (elf-debuglink
-                                               (read-elf "exe")))
-                            (lambda (file crc)
-                              (call-with-output-file #$output
-                                (lambda (port)
-                                  (write (list file crc) port)))))))))
-        (mlet* %store-monad ((drv (gexp->derivation "debuglink" exp))
-                             (x   (built-derivations (list drv))))
-          (call-with-input-file (derivation->output-path drv)
-            (lambda (port)
-              (return (match (read port)
-                        (("exe.debug" crc)
-                         (= crc (debuglink-crc32 (open-input-string "a"))))
-                        (x
-                         (pk 'fail x #f))))))))))
+                      (setenv "PATH" (string-join '(#$%bootstrap-gcc
+                                                    #$%bootstrap-binutils)
+                                                  "/bin:" 'suffix))
+                      (invoke "gcc" "-O0" "-g" #$code "-o" "exe")
+                      (copy-file "exe" "exe.debug")
+                      (invoke "strip" "--only-keep-debug" "exe.debug")
+                      (invoke "strip" "--strip-debug" "exe")
+                      (invoke "objcopy" "--add-gnu-debuglink=exe.debug"
+                              "exe")
+                      (set-debuglink-crc "exe" #$debug)
+                      (call-with-values (lambda ()
+                                          (elf-debuglink
+                                           (call-with-input-file "exe"
+                                             read-elf)))
+                        (lambda (file crc)
+                          (call-with-output-file #$output
+                            (lambda (port)
+                              (write (list file crc) port)))))))))
+    (mlet* %store-monad ((drv (gexp->derivation "debuglink" exp))
+                         (x   (built-derivations (list drv))))
+      (call-with-input-file (derivation->output-path drv)
+        (lambda (port)
+          (return (match (read port)
+                    (("exe.debug" crc)
+                     (= crc (debuglink-crc32 (open-input-string "a"))))
+                    (x
+                     (pk 'fail x #f)))))))))
 
 (test-end "debug-link")
diff --git a/tests/gremlin.scm b/tests/gremlin.scm
index 44237e2ad37..280b1d88192 100644
--- a/tests/gremlin.scm
+++ b/tests/gremlin.scm
@@ -23,7 +23,6 @@
   #:use-module (guix tests)
   #:use-module ((guix utils) #:select (call-with-temporary-directory
                                        target-aarch64?))
-  #:use-module (guix build io)
   #:use-module (guix build utils)
   #:use-module (guix build gremlin)
   #:use-module (gnu packages bootstrap)
@@ -45,6 +44,9 @@
     (_
      #f)))
 
+(define read-elf
+  (compose parse-elf get-bytevector-all))
+
 (define c-compiler
   (or (which "gcc") (which "cc") (which "g++")))
 
@@ -53,7 +55,8 @@
 
 (unless %guile-executable (test-skip 1))
 (test-assert "elf-dynamic-info-needed, executable"
-  (let ((dyninfo (file-dynamic-info %guile-executable)))
+  (let* ((elf     (call-with-input-file %guile-executable read-elf))
+         (dyninfo (elf-dynamic-info elf)))
     (or (not dyninfo)                             ;static executable
         (lset<= string=?
                 (list (string-append "libguile-" (effective-version))
@@ -137,7 +140,9 @@
            (display "int main () { puts(\"hello\"); }" port)))
        (invoke c-compiler "t.c"
                "-Wl,--enable-new-dtags" "-Wl,-rpath=/foo" "-Wl,-rpath=/bar")
-       (let* ((dyninfo (file-dynamic-info "a.out"))
+       (let* ((dyninfo (elf-dynamic-info
+                        (parse-elf (call-with-input-file "a.out"
+                                     get-bytevector-all))))
               (old     (elf-dynamic-info-runpath dyninfo))
               (new     (strip-runpath "a.out"))
               (new*    (strip-runpath "a.out")))
@@ -191,7 +196,10 @@
            (display "// empty file" port)))
        (invoke c-compiler "t.c"
                "-shared" "-Wl,-soname,libfoo.so.2")
-       (let ((dyninfo (file-dynamic-info "a.out")))
-         (elf-dynamic-info-soname dyninfo))))))
+       (let* ((dyninfo (elf-dynamic-info
+                       (parse-elf (call-with-input-file "a.out"
+                                    get-bytevector-all))))
+              (soname  (elf-dynamic-info-soname dyninfo)))
+         soname)))))
 
 (test-end "gremlin")