Add the -empty flag, from OpenBSD. It returns true if the directory

is empty.  There doesn't appear to be another easy way to do this.

mobile# mkdir foo
mobile# mkdir foo/bar
mobile# mkdir bar
mobile# find . -empty
./foo/bar
./bar

usr.bin/find/extern.h

@@ -54,6 +54,7 @@ PLAN	*c_cmin __P((char *));
 PLAN	*c_ctime __P((char *));
 PLAN	*c_delete __P((void));
 PLAN	*c_depth __P((void));
+PLAN	*c_empty __P((void));
 PLAN	*c_exec __P((char ***, int));
 PLAN	*c_flags __P((char *));
 PLAN	*c_execdir __P((char ***));

usr.bin/find/find.1

@@ -181,6 +181,8 @@ recurses down the tree.
 It will not attempt to delete a filename with a ``/''
 character in its pathname relative to "." for security reasons.
 Depth\-first traversal processing is implied by this option.
+.It Ic -empty
+True if the current file or directory is empty.
 .It Ic -exec Ar utility Op argument ... ; 
 True if the program named
 .Ar utility

usr.bin/find/find.h

@@ -41,9 +41,9 @@
 enum ntype {
 	N_AND = 1, 				/* must start > 0 */
 	N_AMIN, N_ATIME, N_CLOSEPAREN, N_CMIN, N_CTIME, N_DEPTH, 
-	N_EXEC, N_EXECDIR, N_EXPR, N_FLAGS,
+	N_EMPTY, N_EXEC, N_EXECDIR, N_EXPR, N_FLAGS,
 	N_FOLLOW, N_FSTYPE, N_GROUP, N_INUM, N_LINKS, N_LS, N_MMIN, 
-        N_MTIME, N_NAME,
+	N_MTIME, N_NAME,
 	N_NEWER, N_NOGROUP, N_NOT, N_NOUSER, N_OK, N_OPENPAREN, N_OR, N_PATH,
 	N_PERM, N_PRINT, N_PRUNE, N_SIZE, N_TYPE, N_USER, N_XDEV,
 	N_PRINT0, N_DELETE, N_MAXDEPTH, N_MINDEPTH

usr.bin/find/function.c

@@ -49,6 +49,7 @@ static const char rcsid[] =
 #include <sys/wait.h>
 #include <sys/mount.h>
 
+#include <dirent.h>
 #include <err.h>
 #include <errno.h>
 #include <fnmatch.h>
@@ -384,6 +385,48 @@ c_exec(argvp, isok)
 	return (new);
 }
  
+/*
+ * -empty functions --
+ *
+ *	True if the file or directory is empty
+ */
+int
+f_empty(plan, entry)
+	PLAN *plan;
+	FTSENT *entry;
+{
+	if (S_ISREG(entry->fts_statp->st_mode) && entry->fts_statp->st_size == 0)
+		return (1);
+	if (S_ISDIR(entry->fts_statp->st_mode)) {
+		struct dirent *dp;
+		int empty;
+		DIR *dir;
+
+		empty = 1;
+		dir = opendir(entry->fts_accpath);
+		if (dir == NULL)
+			err(1, "%s", entry->fts_accpath);
+		for (dp = readdir(dir); dp; dp = readdir(dir))
+			if (dp->d_name[0] != '.' ||
+			    (dp->d_name[1] != '\0' &&
+			     (dp->d_name[1] != '.' || dp->d_name[2] != '\0'))) {
+				empty = 0;
+				break;
+			}
+		closedir(dir);
+		return (empty);
+	}
+	return (0);
+}
+
+PLAN *
+c_empty()
+{
+	ftsoptions &= ~FTS_NOSTAT;
+
+	return (palloc(N_EMPTY, f_empty));
+}
+
 /*
  * -execdir utility [arg ... ] ; functions --
  *

usr.bin/find/option.c

@@ -68,6 +68,7 @@ static OPTION const options[] = {
 	{ "-ctime",	N_CTIME,	c_ctime,	O_ARGV },
 	{ "-delete",	N_DELETE,	c_delete,	O_ZERO },
 	{ "-depth",	N_DEPTH,	c_depth,	O_ZERO },
+	{ "-empty",	N_EMPTY,	c_empty,	O_ZERO },
 	{ "-exec",	N_EXEC,		c_exec,		O_ARGVP },
 	{ "-execdir",	N_EXECDIR,	c_execdir,	O_ARGVP },
 	{ "-flags",	N_FLAGS,	c_flags,	O_ARGV },