procyberian/emacs
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

(backup-buffer-copy): Check backup directory is writable, to avoid

Browse source 
infloop deleting old backup.
This commit is contained in:
Glenn Morris 2007-08-22 03:49:45 +00:00
parent 11bdb42c26
commit 90b64c0920
2 changed files with 17 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

3
lisp/ChangeLog
View file

@ -1,5 +1,8 @@
2007-08-22 Glenn Morris <rgm@gnu.org>
* files.el (backup-buffer-copy): Check backup directory is
writable, to avoid infloop deleting old backup.
* mail/rmail.el (rmail-movemail-variant-p): Call on load to set
movemail related variables.
(rmail-insert-inbox-text): Use only rmail-movemail-program, which

14
lisp/files.el
View file

@ -3173,6 +3173,11 @@ BACKUPNAME is the backup file name, which is the old file renamed."
(defun backup-buffer-copy (from-name to-name modes)
(let ((umask (default-file-modes)))
(dir (or (file-name-directory to-name)
default-directory)))
;; Can't delete or create files in a read-only directory.
(unless (file-writable-p dir)
(signal 'file-error (list "Directory is not writable" dir)))
(unwind-protect
(progn
;; Create temp files with strict access rights. It's easy to
@ -3181,6 +3186,11 @@ BACKUPNAME is the backup file name, which is the old file renamed."
(set-default-file-modes ?\700)
(while (condition-case ()
(progn
;; If we allow for the possibility of something
;; creating the file between delete and copy
;; (below), we must also allow for the
;; possibility of something deleting it between
;; a file-exists-p check and a delete.
(condition-case nil
(delete-file to-name)
(file-error nil))
@ -3189,6 +3199,10 @@ BACKUPNAME is the backup file name, which is the old file renamed."
(file-already-exists t))
;; The file was somehow created by someone else between
;; `delete-file' and `copy-file', so let's try again.
;; Does that every actually happen in practice?
;; This is a potential infloop, which seems bad...
;; rms says "I think there is also a possible race
;; condition for making backup files" (emacs-devel 20070821).
nil))
;; Reset the umask.
(set-default-file-modes umask)))