tftpd: show help if stdin is not a socket

diff --git a/networking/tftp.c b/networking/tftp.c
index 07d672dcbc1c73a08f5ce5d32545115002ee9009..eb39e9c54bbfdb275193d9fc9edaed1e969c77c2 100644 (file)
--- a/networking/tftp.c
+++ b/networking/tftp.c
@@ -653,8 +653,15 @@ int tftpd_main(int argc UNUSED_PARAM, char **argv)
        INIT_G();
 
        our_lsa = get_sock_lsa(STDIN_FILENO);
-       if (!our_lsa)
-               bb_perror_msg_and_die("stdin is not a socket");
+       if (!our_lsa) {
+               /* This is confusing:
+                *bb_error_msg_and_die("stdin is not a socket");
+                * Better: */
+               bb_show_usage();
+               /* Help text says that tftpd must be used as inetd service,
+                * which is by far the most usual cause of get_sock_lsa
+                * failure */
+       }
        peer_lsa = xzalloc(LSA_LEN_SIZE + our_lsa->len);
        peer_lsa->len = our_lsa->len;