From 8f2416cbda412ee42b952810f47c5ccef3560932 Mon Sep 17 00:00:00 2001
From: Cem Keylan <cem@ckyln.com>
Date: Mon, 20 Jul 2020 01:18:11 +0300
Subject: shalt: change coding style, add response, parse arguments with arg.h

---
 bin/arg.h   | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 bin/shalt.c | 37 ++++++++++++++++++++++++++++++-------
 rc.shutdown |  2 +-
 3 files changed, 81 insertions(+), 8 deletions(-)
 create mode 100644 bin/arg.h

diff --git a/bin/arg.h b/bin/arg.h
new file mode 100644
index 0000000..a22e019
--- /dev/null
+++ b/bin/arg.h
@@ -0,0 +1,50 @@
+/*
+ * 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;\
+				}\
+				int i_;\
+				for (i_ = 1, brk_ = 0, argv_ = argv;\
+						argv[0][i_] && !brk_;\
+						i_++) {\
+					if (argv_ != argv)\
+						break;\
+					argc_ = argv[0][i_];\
+					switch (argc_)
+
+#define ARGEND			}\
+			}
+
+#define ARGC()		argc_
+
+#define EARGF(x)	((argv[0][i_+1] == '\0' && argv[1] == NULL)?\
+				((x), abort(), (char *)0) :\
+				(brk_ = 1, (argv[0][i_+1] != '\0')?\
+					(&argv[0][i_+1]) :\
+					(argc--, argv++, argv[0])))
+
+#define ARGF()		((argv[0][i_+1] == '\0' && argv[1] == NULL)?\
+				(char *)0 :\
+				(brk_ = 1, (argv[0][i_+1] != '\0')?\
+					(&argv[0][i_+1]) :\
+					(argc--, argv++, argv[0])))
+
+#endif
diff --git a/bin/shalt.c b/bin/shalt.c
index b2e199d..1fa5428 100644
--- a/bin/shalt.c
+++ b/bin/shalt.c
@@ -1,10 +1,33 @@
-// shalt -- simple halt utility
+/* shalt -- simple halt utility */
 #include <sys/reboot.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 
-int main (int argc, char *argv[]) {
-    switch ((int)argv[argc < 2 ? 0 : 1][0]) {
-    case 'p': reboot(RB_POWER_OFF); break;
-    case 'r': reboot(RB_AUTOBOOT); break;
-    default: return 1;
-    }; return 0;
+static char *argv0;
+#include "arg.h"
+
+static void
+usage(void)
+{
+	fprintf(stderr, "usage: %s [-pr]\n", argv0);
+	exit(1);
+}
+
+int
+main(int argc, char *argv[])
+{
+	ARGBEGIN {
+		case 'p':
+			reboot(RB_POWER_OFF);
+			break;
+		case 'r':
+			reboot(RB_AUTOBOOT);
+			break;
+		default:
+			usage();
+	} ARGEND
+
+	if (argc != 2) usage();
+	return 0;
 }
diff --git a/rc.shutdown b/rc.shutdown
index a3f14d5..daa346d 100755
--- a/rc.shutdown
+++ b/rc.shutdown
@@ -41,4 +41,4 @@ out "Remounting rootfs as readonly..."; {
 
 run_hook post.shutdown
 
-case "$1" in reboot) shalt r ;; poweroff) shalt p; esac
+case "$1" in reboot) shalt -r ;; poweroff) shalt -p; esac
-- 
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