exit unsuccessfully on empty passphrase if input is a tty

allows user to press ctrl-d to abort

Signed-off-by: Ludwig Nussel <ludwig.nussel@suse.de>

Index: hashalot-0.3/hashalot.c
===================================================================
--- hashalot-0.3.orig/hashalot.c
+++ hashalot-0.3/hashalot.c
@@ -135,10 +135,14 @@ phash_lookup(const char phash_name[], si
 static char *
 xgetpass(const char *prompt)
 {
-	if (isatty(STDIN_FILENO))	/* terminal */
-		return getpass(prompt); /* FIXME getpass(3) obsolete */
-	else {				/* file descriptor */
-		char *pass = NULL;
+	char *pass = NULL;
+	if (isatty(STDIN_FILENO)) {	/* terminal */
+		pass = getpass(prompt); /* FIXME getpass(3) obsolete */
+		if(!pass || !*pass) {
+			exit(EXIT_FAILURE);
+		}
+		return pass;
+	} else {				/* file descriptor */
 		int buflen, i;
 
 		buflen=0;