Implement file locks for remote files (Bug#49261)

* doc/lispref/files.texi (Magic File Names): Add file-locked-p,
lock-file and unlock-file.

* etc/NEWS: Tramp supports file locks now.

* lisp/net/tramp-adb.el (tramp-adb-file-name-handler-alist):
Add `file-locked-p', `lock-file' and `unlock-file'.
(tramp-adb-handle-write-region): Handle LOCKNAME.

* lisp/net/tramp-archive.el (tramp-archive-file-name-handler-alist):
Add `file-locked-p', `lock-file' and `unlock-file'.

* lisp/net/tramp-crypt.el (tramp-crypt-file-name-handler-alist):
Add `file-locked-p', `lock-file' and `unlock-file'.
(tramp-crypt-handle-file-locked-p, tramp-crypt-handle-lock-file)
(tramp-crypt-handle-unlock-file): New defun.

* lisp/net/tramp-fuse.el (tramp-fuse-mounted-p): Simplify.
(tramp-fuse-unmount): New defun.

* lisp/net/tramp-gvfs.el (tramp-gvfs-file-name-handler-alist):
Add `file-locked-p', `lock-file' and `unlock-file'.
(tramp-gvfs-maybe-open-connection): Set "lock-pid" connection property.

* lisp/net/tramp-rclone.el (tramp-rclone-file-name-handler-alist):
Add `file-locked-p', `lock-file' and `unlock-file'.
(tramp-rclone-maybe-open-connection): Set "lock-pid" connection property.

* lisp/net/tramp-sh.el (tramp-sh-file-name-handler-alist):
Add `file-locked-p', `lock-file' and `unlock-file'.
(tramp-sh-handle-write-region): Handle LOCKNAME.

* lisp/net/tramp-smb.el (tramp-smb-file-name-handler-alist):
Add `file-locked-p', `lock-file' and `unlock-file'.
(tramp-smb-handle-copy-directory): Use `sleep-for'.
(tramp-smb-handle-write-region): Handle LOCKNAME.

* lisp/net/tramp-sshfs.el (tramp-sshfs-file-name-handler-alist):
Add `file-locked-p', `lock-file' and `unlock-file'.
(tramp-sshfs-handle-write-region): Handle LOCKNAME.
(tramp-sshfs-maybe-open-connection): Set "lock-pid" connection property.

* lisp/net/tramp-sudoedit.el (tramp-sudoedit-file-name-handler-alist):
Add `file-locked-p', `lock-file' and `unlock-file'.
(tramp-sudoedit-maybe-open-connection):
Set "lock-pid" connection property.

* lisp/net/tramp.el (tramp-file-name-for-operation):
Add `file-locked-p', `lock-file' and `unlock-file'.
(tramp-make-lock-name, tramp-get-lock-file, tramp-get-lock-pid)
(tramp-handle-file-locked-p, tramp-handle-lock-file)
(tramp-handle-unlock-file): New defuns.
(tramp-lock-file-contents-regexp): New regexp.
(tramp-handle-write-region): Handle LOCKNAME.

* src/filelock.c (lock_file, unlock_file_body, Ffile_locked_p):
Call handler if exists.
(Flock_file, Funlock_file): New defuns.
(Qlock_file, Qunlock_file, Qfile_locked_p): Declare symbols.
(Slock_file, Sunlock_file): Declare subroutines.

* test/lisp/net/tramp-archive-tests.el
(tramp-archive-test40-make-nearby-temp-file)
(tramp-archive-test43-file-system-info): Rename.

* test/lisp/net/tramp-tests.el (top): Set `create-lockfiles' to nil.
(tramp--test-fuse-p): New defun.
(tramp-test14-delete-directory): Use it.
(tramp-test39-lock-file): New test.
(tramp-test40-make-nearby-temp-file)
(tramp-test41-special-characters)
(tramp-test41-special-characters-with-stat)
(tramp-test41-special-characters-with-perl)
(tramp-test41-special-characters-with-ls, tramp-test42-utf8)
(tramp-test42-utf8-with-stat, tramp-test42-utf8-with-perl)
(tramp-test42-utf8-with-ls, tramp-test43-file-system-info)
(tramp-test44-asynchronous-requests, tramp-test45-auto-load)
(tramp-test45-delay-load, tramp-test45-recursive-load)
(tramp-test45-remote-load-path, tramp-test46-unload): Rename.
(tramp--test-special-characters, tramp--test-utf8)
(tramp--test-asynchronous-requests-timeout): Modify docstring.

1 files changed, 7 insertions, 0 deletions

diff --git a/lisp/net/tramp-sudoedit.el b/lisp/net/tramp-sudoedit.el
index d6417094bae..aa6f85ec6ef 100644
--- a/lisp/net/tramp-sudoedit.el
+++ b/lisp/net/tramp-sudoedit.el
@@ -88,6 +88,7 @@ See `tramp-actions-before-shell' for more info.")
     (file-exists-p . tramp-sudoedit-handle-file-exists-p)
     (file-in-directory-p . tramp-handle-file-in-directory-p)
     (file-local-copy . tramp-handle-file-local-copy)
+    (file-locked-p . tramp-handle-file-locked-p)
     (file-modes . tramp-handle-file-modes)
     (file-name-all-completions
      . tramp-sudoedit-handle-file-name-all-completions)
@@ -115,6 +116,7 @@ See `tramp-actions-before-shell' for more info.")
     (insert-directory . tramp-handle-insert-directory)
     (insert-file-contents . tramp-handle-insert-file-contents)
     (load . tramp-handle-load)
+    (lock-file . tramp-handle-lock-file)
     (make-auto-save-file-name . tramp-handle-make-auto-save-file-name)
     (make-directory . tramp-sudoedit-handle-make-directory)
     (make-directory-internal . ignore)
@@ -136,6 +138,7 @@ See `tramp-actions-before-shell' for more info.")
     (tramp-get-remote-uid . tramp-sudoedit-handle-get-remote-uid)
     (tramp-set-file-uid-gid . tramp-sudoedit-handle-set-file-uid-gid)
     (unhandled-file-name-directory . ignore)
+    (unlock-file . tramp-handle-unlock-file)
     (vc-registered . ignore)
     (verify-visited-file-modtime . tramp-handle-verify-visited-file-modtime)
     (write-region . tramp-sudoedit-handle-write-region))
@@ -713,6 +716,7 @@ ID-FORMAT valid values are `string' and `integer'."
 (defun tramp-sudoedit-handle-write-region
   (start end filename &optional append visit lockname mustbenew)
   "Like `write-region' for Tramp files."
+  (setq filename (expand-file-name filename))
   (with-parsed-tramp-file-name filename nil
     (let* ((uid (or (tramp-compat-file-attribute-user-id
 		     (file-attributes filename 'integer))
@@ -776,6 +780,9 @@ connection if a previous connection has died for some reason."
       (process-put p 'vector vec)
       (set-process-query-on-exit-flag p nil)
 
+      ;; Mark process for filelock.
+      (tramp-set-connection-property p "lock-pid" (truncate (time-to-seconds)))
+
       ;; Set connection-local variables.
       (tramp-set-connection-local-variables vec)