From 624d45a10f4d2d84a32a4e9fbcd370aa653271f8 Mon Sep 17 00:00:00 2001
From: Mattias Andrée <maandree@kth.se>
Date: Fri, 4 Sep 2020 21:28:33 +0200
Subject: Do not accept arguments
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: Mattias Andrée <maandree@kth.se>
---
 LICENSE      |  2 +-
 Makefile     |  2 +-
 arg.h        | 35 +++++++++++++++++++++++++++++++++++
 mongoclock.c | 20 ++++++++++++++++++++
 4 files changed, 57 insertions(+), 2 deletions(-)
 create mode 100644 arg.h

diff --git a/LICENSE b/LICENSE
index d4d1e8b..9466715 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,6 +1,6 @@
 ISC License
 
-© 2013, 2015, 2017 Mattias Andrée <maandree@kth.se>
+© 2013, 2015, 2017, 2020 Mattias Andrée <maandree@kth.se>
 
 Permission to use, copy, modify, and/or distribute this software for any
 purpose with or without fee is hereby granted, provided that the above
diff --git a/Makefile b/Makefile
index b0a867a..f197990 100644
--- a/Makefile
+++ b/Makefile
@@ -13,7 +13,7 @@ all: mongoclock
 mongoclock: mongoclock.o
 	$(CC) -o $@ $^ $(LDFLAGS)
 
-mongoclock.o: mongoclock.c $(DIGITS)
+mongoclock.o: mongoclock.c arg.h $(DIGITS)
 	$(CC) -c -o $@ mongoclock.c $(CPPFLAGS) $(CFLAGS)
 
 mongo_0.h: digit.sh
diff --git a/arg.h b/arg.h
new file mode 100644
index 0000000..54e3874
--- /dev/null
+++ b/arg.h
@@ -0,0 +1,35 @@
+/*
+ * Copy me if you can.
+ * by 20h
+ */
+
+#ifndef ARG_H__
+#define ARG_H__
+
+extern char *argv0;
+
+/* use main(int argc, char *argv[]) */
+#define ARGBEGIN	for (argv0 = *argv, argv++, argc--;\
+					argv[0] && argv[0][0] == '-'\
+					&& argv[0][1];\
+					argc--, argv++) {\
+				char argc_;\
+				char **argv_;\
+				int brk_;\
+				if (argv[0][1] == '-' && argv[0][2] == '\0') {\
+					argv++;\
+					argc--;\
+					break;\
+				}\
+				for (brk_ = 0, argv[0]++, argv_ = argv;\
+						argv[0][0] && !brk_;\
+						argv[0]++) {\
+					if (argv_ != argv)\
+						break;\
+					argc_ = argv[0][0];\
+					switch (argc_)
+
+#define ARGEND			}\
+			}
+
+#endif
diff --git a/mongoclock.c b/mongoclock.c
index e2d7e20..d94fd28 100644
--- a/mongoclock.c
+++ b/mongoclock.c
@@ -5,9 +5,12 @@
 #include <signal.h>
 #include <stdint.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <time.h>
 #include <unistd.h>
 
+#include "arg.h"
+
 #define DX 16
 #define DY 12
 #define DC 16
@@ -32,6 +35,15 @@ static const char **mongo_ds[] = {
 static volatile sig_atomic_t caught_sigterm = 0;
 static volatile sig_atomic_t caught_sigwinch = 1;
 
+char *argv0;
+
+static void
+usage(void)
+{
+	fprintf(stderr, "usage: %s\n", argv0);
+	exit(1);
+}
+
 static void
 sigterm(int signo)
 {
@@ -77,6 +89,14 @@ main(int argc, char *argv[])
 	struct itimerspec itimerspec;
 	uint64_t _overrun;
 
+	ARGBEGIN {
+	default:
+		usage();
+	} ARGEND;
+
+	if (argc)
+		usage();
+
 	fprintf(stdout, "\033[?1049h\033[?25l");
 
 	if (clock_gettime(CLOCK_REALTIME, &itimerspec.it_value))
-- 
cgit v1.2.3-70-g09d2