[Emacs-diffs] master 785a4a1: Fix a couple of make-temp-file races

[Paul Eggert]

branch: master
commit 785a4a1d52fd7da3f3169fda26841341667c1661
Author: Paul Eggert <address@hidden>
Commit: Paul Eggert <address@hidden>

    Fix a couple of make-temp-file races
    
    * lisp/emacs-lisp/autoload.el (autoload--save-buffer):
    * lisp/emacs-lisp/bytecomp.el (byte-compile-file):
    Use make-temp-file, not make-temp-name, to avoid an unlikely race
    that could lose data.  Remove the deletion hook as quickly as
    possible after the file is renamed; though a race still remains
    here, it is smaller than before.
---
 lisp/emacs-lisp/autoload.el | 10 +++++-----
 lisp/emacs-lisp/bytecomp.el | 40 +++++++++++++++++++++-------------------
 2 files changed, 26 insertions(+), 24 deletions(-)

diff --git a/lisp/emacs-lisp/autoload.el b/lisp/emacs-lisp/autoload.el
index 8fe9401..4a9bd6d 100644
--- a/lisp/emacs-lisp/autoload.el
+++ b/lisp/emacs-lisp/autoload.el
@@ -875,16 +875,16 @@ FILE's modification time."
   "Save current buffer to its file, atomically."
   ;; Copied from byte-compile-file.
   (let* ((version-control 'never)
-         (tempfile (make-temp-name buffer-file-name))
+         (tempfile (make-temp-file buffer-file-name))
          (kill-emacs-hook
           (cons (lambda () (ignore-errors (delete-file tempfile)))
                 kill-emacs-hook)))
     (write-region (point-min) (point-max) tempfile nil 1)
     (backup-buffer)
-    (rename-file tempfile buffer-file-name t)
-    (set-buffer-modified-p nil)
-    (set-visited-file-modtime)
-    (or noninteractive (message "Wrote %s" buffer-file-name))))
+    (rename-file tempfile buffer-file-name t))
+  (set-buffer-modified-p nil)
+  (set-visited-file-modtime)
+  (or noninteractive (message "Wrote %s" buffer-file-name)))
 
 (defun autoload-save-buffers ()
   (while autoload-modified-buffers
diff --git a/lisp/emacs-lisp/bytecomp.el b/lisp/emacs-lisp/bytecomp.el
index fdd4276..5fa7389 100644
--- a/lisp/emacs-lisp/bytecomp.el
+++ b/lisp/emacs-lisp/bytecomp.el
@@ -1888,25 +1888,27 @@ The value is non-nil if there were no errors, nil if 
errors."
          (insert "\n")                 ; aaah, unix.
          (if (file-writable-p target-file)
              ;; We must disable any code conversion here.
-             (let* ((coding-system-for-write 'no-conversion)
-                    ;; Write to a tempfile so that if another Emacs
-                    ;; process is trying to load target-file (eg in a
-                    ;; parallel bootstrap), it does not risk getting a
-                    ;; half-finished file.  (Bug#4196)
-                    (tempfile (make-temp-name target-file))
-                    (kill-emacs-hook
-                     (cons (lambda () (ignore-errors (delete-file tempfile)))
-                           kill-emacs-hook)))
-               (write-region (point-min) (point-max) tempfile nil 1)
-               ;; This has the intentional side effect that any
-               ;; hard-links to target-file continue to
-               ;; point to the old file (this makes it possible
-               ;; for installed files to share disk space with
-               ;; the build tree, without causing problems when
-               ;; emacs-lisp files in the build tree are
-               ;; recompiled).  Previously this was accomplished by
-               ;; deleting target-file before writing it.
-               (rename-file tempfile target-file t)
+             (progn
+               (let* ((coding-system-for-write 'no-conversion)
+                      ;; Write to a tempfile so that if another Emacs
+                      ;; process is trying to load target-file (eg in a
+                      ;; parallel bootstrap), it does not risk getting a
+                      ;; half-finished file.  (Bug#4196)
+                      (tempfile (make-temp-file target-file))
+                      (kill-emacs-hook
+                       (cons (lambda () (ignore-errors
+                                          (delete-file tempfile)))
+                             kill-emacs-hook)))
+                 (write-region (point-min) (point-max) tempfile nil 1)
+                 ;; This has the intentional side effect that any
+                 ;; hard-links to target-file continue to
+                 ;; point to the old file (this makes it possible
+                 ;; for installed files to share disk space with
+                 ;; the build tree, without causing problems when
+                 ;; emacs-lisp files in the build tree are
+                 ;; recompiled).  Previously this was accomplished by
+                 ;; deleting target-file before writing it.
+                 (rename-file tempfile target-file t))
                (or noninteractive (message "Wrote %s" target-file)))
            ;; This is just to give a better error message than write-region
            (let ((exists (file-exists-p target-file)))