rm: new option --dir (-d) to remove empty directories

Add new option to rm (-d/--dir), which allows removal of
empty directories, while still safely disallowing removal
of non-empty ones.

This improves compatibility with Mac OS X and BSD systems,
which honor the -d option.

* src/remove.c (rm_fts): Remove empty directories when requested.
* src/remove.h (rm_options) [remove_empty_directories]: New member.
* src/rm.c (long_opts, usage, main): Update usage and option parsing.
(rm_option_init): Initialize the new member.
* src/mv.c (rm_option_init): Initialize the new member.
* tests/rm/d-1: New test case - successfully delete empty dir.
* tests/rm/d-2: New test case - refuse to delete nonempty dir.
* tests/Makefile.am (TESTS): Add them.

4 files changed, 19 insertions, 4 deletions

diff --git a/src/mv.c b/src/mv.c
index ee2f5a10c..4f5708eb2 100644
--- a/src/mv.c
+++ b/src/mv.c
@@ -73,6 +73,7 @@ static void
 rm_option_init (struct rm_options *x)
 {
   x->ignore_missing_files = false;
+  x->remove_empty_directories = true;
   x->recursive = true;
   x->one_file_system = false;
 
diff --git a/src/remove.c b/src/remove.c
index 5ebd2ce43..61ba5f372 100644
--- a/src/remove.c
+++ b/src/remove.c
@@ -414,11 +414,15 @@ rm_fts (FTS *fts, FTSENT *ent, struct rm_options const *x)
   switch (ent->fts_info)
     {
     case FTS_D:			/* preorder directory */
-      if (! x->recursive)
+      if (! x->recursive
+          && !(x->remove_empty_directories
+               && is_empty_dir (fts->fts_cwd_fd, ent->fts_accpath)))
         {
-          /* This is the first (pre-order) encounter with a directory.
+          /* This is the first (pre-order) encounter with a directory
+             that we can not delete.
              Not recursive, so arrange to skip contents.  */
-          error (0, EISDIR, _("cannot remove %s"), quote (ent->fts_path));
+          int err = x->remove_empty_directories ? ENOTEMPTY : EISDIR;
+          error (0, err, _("cannot remove %s"), quote (ent->fts_path));
           mark_ancestor_dirs (ent);
           fts_skip_tree (fts, ent);
           return RM_ERROR;
diff --git a/src/remove.h b/src/remove.h
index 4eab2821f..f994517af 100644
--- a/src/remove.h
+++ b/src/remove.h
@@ -49,6 +49,9 @@ struct rm_options
   /* If true, recursively remove directories.  */
   bool recursive;
 
+  /* If true, remove empty directories.  */
+  bool remove_empty_directories;
+
   /* Pointer to the device and inode numbers of '/', when --recursive
      and preserving '/'.  Otherwise NULL.  */
   struct dev_ino *root_dev_ino;
diff --git a/src/rm.c b/src/rm.c
index 02809f214..a45594e42 100644
--- a/src/rm.c
+++ b/src/rm.c
@@ -77,6 +77,7 @@ static struct option const long_opts[] =
   {"-presume-input-tty", no_argument, NULL, PRESUME_INPUT_TTY_OPTION},
 
   {"recursive", no_argument, NULL, 'r'},
+  {"dir", no_argument, NULL, 'd'},
   {"verbose", no_argument, NULL, 'v'},
   {GETOPT_HELP_OPTION_DECL},
   {GETOPT_VERSION_OPTION_DECL},
@@ -154,6 +155,7 @@ Remove (unlink) the FILE(s).\n\
       --no-preserve-root  do not treat '/' specially\n\
       --preserve-root   do not remove '/' (default)\n\
   -r, -R, --recursive   remove directories and their contents recursively\n\
+  -d, --dir             remove empty directories\n\
   -v, --verbose         explain what is being done\n\
 "), stdout);
       fputs (HELP_OPTION_DESCRIPTION, stdout);
@@ -189,6 +191,7 @@ rm_option_init (struct rm_options *x)
   x->ignore_missing_files = false;
   x->interactive = RMI_SOMETIMES;
   x->one_file_system = false;
+  x->remove_empty_directories = false;
   x->recursive = false;
   x->root_dev_ino = NULL;
   x->stdin_tty = isatty (STDIN_FILENO);
@@ -220,10 +223,14 @@ main (int argc, char **argv)
   /* Try to disable the ability to unlink a directory.  */
   priv_set_remove_linkdir ();
 
-  while ((c = getopt_long (argc, argv, "firvIR", long_opts, NULL)) != -1)
+  while ((c = getopt_long (argc, argv, "dfirvIR", long_opts, NULL)) != -1)
     {
       switch (c)
         {
+        case 'd':
+          x.remove_empty_directories = true;
+          break;
+
         case 'f':
           x.interactive = RMI_NEVER;
           x.ignore_missing_files = true;