commit 7347caeb9d902d3fca2c11f69a55a3e578d93bfe

Author: Paul Eggert <eggert@cs.ucla.edu>

Date:   Wed Apr 20 19:34:57 2022 -0700

    backupfile: fix bug when renaming simple backups

    * lib/backupfile.c (backupfile_internal): Fix bug when RENAME

    and when doing simple backups.  Problem reported by Steve Ward in:

    https://bugs.gnu.org/55029

diff --git a/lib/backupfile.c b/lib/backupfile.c

index 1e9290a187..d9f465a3e0 100644

--- a/lib/backupfile.c

+++ b/lib/backupfile.c

@@ -332,7 +332,7 @@ backupfile_internal (int dir_fd, char const *file,

     return s;

   DIR *dirp = NULL;

-  int sdir = AT_FDCWD;

+  int sdir = dir_fd;

   idx_t base_max = 0;

   while (true)

     {

@@ -371,10 +371,9 @@ backupfile_internal (int dir_fd, char const *file,

       if (! rename)

         break;

-      int olddirfd = sdir < 0 ? dir_fd : sdir;

-      idx_t offset = sdir < 0 ? 0 : base_offset;

+      idx_t offset = backup_type == simple_backups ? 0 : base_offset;

       unsigned flags = backup_type == simple_backups ? 0 : RENAME_NOREPLACE;

-      if (renameatu (olddirfd, file + offset, sdir, s + offset, flags) == 0)

+      if (renameatu (sdir, file + offset, sdir, s + offset, flags) == 0)

         break;

       int e = errno;

       if (! (e == EEXIST && extended))