diff --git a/libbb/wfopen_input.c b/libbb/wfopen_input.c
index 1b4928e..a7c1c32 100644
--- a/libbb/wfopen_input.c
+++ b/libbb/wfopen_input.c
@@ -10,8 +10,6 @@
 /* A number of applets need to open a file for reading, where the filename
  * is a command line arg.  Since often that arg is '-' (meaning stdin),
  * we avoid testing everywhere by consolidating things in this routine.
- *
- * Note: we also consider "" to mean stdin (for 'cmp' at least).
  */
 
 #include "libbb.h"
@@ -21,11 +19,30 @@
 	FILE *fp = stdin;
 
 	if (filename != bb_msg_standard_input
-	 && filename[0]
 	 && NOT_LONE_DASH(filename)
 	) {
 		fp = fopen_or_warn(filename, "r");
 	}
-
 	return fp;
 }
+
+FILE *xfopen_stdin(const char *filename)
+{
+	FILE *fp = fopen_or_warn_stdin(filename);
+	if (fp)
+		return fp;
+	xfunc_die();	/* We already output an error message. */
+}
+
+int open_or_warn_stdin(const char *filename)
+{
+	int fd = STDIN_FILENO;
+
+	if (filename != bb_msg_standard_input
+	 && NOT_LONE_DASH(filename)
+	) {
+		fd = open_or_warn(filename, O_RDONLY);
+	}
+
+	return fd;
+}