fix(chwrite): Correct argument parsing

Make it conform strictly to the help message

1 files changed, 21 insertions, 3 deletions

diff --git a/chwrite/chwrite.c b/chwrite/chwrite.c
index 6be8ec8..395cf91 100644
--- a/chwrite/chwrite.c
+++ b/chwrite/chwrite.c
@@ -4,6 +4,7 @@
 #include <fcntl.h>
 #include <errno.h>
 #include <stdio.h>
+#include <string.h>
 
 static void
 help_message(void) {
@@ -25,14 +26,31 @@ main(int argc, char *argv[]) {
         help_message();
         return 0;
     }
+    for (i = 1; i < argc; ++i) {
+        if (!strcmp(argv[i], "-h") || !strcmp(argv[i], "--help")) {
+            help_message();
+            return 0;
+        }
+    }
 
-    operation = argv[1][0];
-
-    if (operation != '+' && operation != '-') {
+    if (!strcmp(argv[1], "+") || !strcmp(argv[1], "+w")) {
+        operation = '+';
+    }
+    else if (!strcmp(argv[1], "-") || !strcmp(argv[1], "-w")) {
+        operation = '-';
+    }
+    else {
+        printf("Invalid argument '%s'!\n", argv[1]);
         help_message();
         return 1;
     }
 
+    if (argc == 2) {
+        printf("Not enough arguments!\n");
+        help_message();
+        return 2;
+    }
+
     for (i = 2; i < argc; ++i) {
         f = open(argv[i], 0);
         if (f == -1)