Improve "rmdir --ignore-fail-on-non-empty"

* src/rmdir.c (remove_parents, main): With --ignore-fail-on-non-empty,
suppress a diagnostic also for other errno values, which can arise
with read-only media or when the parent directory has the immutable
attribute (set via chattr +i).
(errno_may_be_empty, ignorable_failure): New functions.
* src/remove.c (is_empty_dir): Move function to ...
* src/system.h (is_empty_dir): ...here, and make it inline.
Suggested by Josselin Mouette in <http://bugs.debian.org/363011>
via Bob Proulx.
* NEWS: Mention the improvement.

1 files changed, 30 insertions, 0 deletions

diff --git a/src/system.h b/src/system.h
index 54c8a8b3d..b0b954510 100644
--- a/src/system.h
+++ b/src/system.h
@@ -384,6 +384,36 @@ readdir_ignoring_dot_and_dotdot (DIR *dirp)
     }
 }
 
+/* Return true if DIR is determined to be an empty directory.  */
+static inline bool
+is_empty_dir (int fd_cwd, char const *dir)
+{
+  DIR *dirp;
+  struct dirent const *dp;
+  int saved_errno;
+  int fd = openat (fd_cwd, dir,
+		   (O_RDONLY | O_DIRECTORY
+		    | O_NOCTTY | O_NOFOLLOW | O_NONBLOCK));
+
+  if (fd < 0)
+    return false;
+
+  dirp = fdopendir (fd);
+  if (dirp == NULL)
+    {
+      close (fd);
+      return false;
+    }
+
+  errno = 0;
+  dp = readdir_ignoring_dot_and_dotdot (dirp);
+  saved_errno = errno;
+  closedir (dirp);
+  if (dp != NULL)
+    return false;
+  return saved_errno == 0 ? true : false;
+}
+
 /* Factor out some of the common --help and --version processing code.  */
 
 /* These enum values cannot possibly conflict with the option values