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.

3 files changed, 62 insertions, 36 deletions

diff --git a/src/remove.c b/src/remove.c
index de8f5ffc9..fe603bbc0 100644
--- a/src/remove.c
+++ b/src/remove.c
@@ -1,5 +1,5 @@
 /* remove.c -- core functions for removing files and directories
-   Copyright (C) 88, 90, 91, 1994-2007 Free Software Foundation, Inc.
+   Copyright (C) 88, 90, 91, 1994-2008 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -726,36 +726,6 @@ AD_is_removable (Dirstack_state const *ds, char const *file)
   return ! (top->unremovable && hash_lookup (top->unremovable, file));
 }
 
-/* Return true if DIR is determined to be an empty directory.  */
-static 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;
-}
-
 /* Return -1 if FILE is an unwritable non-symlink,
    0 if it is writable or some other type of file,
    a positive error number if there is some problem in determining the answer.
diff --git a/src/rmdir.c b/src/rmdir.c
index 96aa9af22..bb1a0c8b3 100644
--- a/src/rmdir.c
+++ b/src/rmdir.c
@@ -74,13 +74,41 @@ static struct option const longopts[] =
 
 /* Return true if ERROR_NUMBER is one of the values associated
    with a failed rmdir due to non-empty target directory.  */
-
 static bool
 errno_rmdir_non_empty (int error_number)
 {
   return (error_number == RMDIR_ERRNO_NOT_EMPTY);
 }
 
+/* Return true if when rmdir fails with errno == ERROR_NUMBER
+   the directory may be empty.  */
+static bool
+errno_may_be_empty (int error_number)
+{
+  switch (error_number)
+    {
+    case EACCES:
+    case EPERM:
+    case EROFS:
+    case EEXIST:
+    case EBUSY:
+      return true;
+    default:
+      return false;
+    }
+}
+
+/* Return true if an rmdir failure with errno == error_number
+   for DIR is ignorable.  */
+static bool
+ignorable_failure (int error_number, char const *dir)
+{
+  return (ignore_fail_on_non_empty
+	  && (errno_rmdir_non_empty (error_number)
+	      || (errno_may_be_empty (error_number)
+		  && is_empty_dir (AT_FDCWD, dir))));
+}
+
 /* Remove any empty parent directories of DIR.
    If DIR contains slash characters, at least one of them
    (beginning with the rightmost) is replaced with a NUL byte.
@@ -113,8 +141,7 @@ remove_parents (char *dir)
       if (!ok)
 	{
 	  /* Stop quietly if --ignore-fail-on-non-empty. */
-	  if (ignore_fail_on_non_empty
-	      && errno_rmdir_non_empty (errno))
+	  if (ignorable_failure (errno, dir))
 	    {
 	      ok = true;
 	    }
@@ -210,8 +237,7 @@ main (int argc, char **argv)
 
       if (rmdir (dir) != 0)
 	{
-	  if (ignore_fail_on_non_empty
-	      && errno_rmdir_non_empty (errno))
+	  if (ignorable_failure (errno, dir))
 	    continue;
 
 	  /* Here, the diagnostic is less precise, since we have no idea
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