add control character sanitization

kissy.c

@@ -25,6 +25,7 @@
 #include <string.h>
 #include <pwd.h>
 #include <stdbool.h>
+#include <ctype.h>
 
 // mreowww meow nya :3
 
@@ -64,11 +65,20 @@ int main (int argc, char **argv) {
     char* user = pw2->pw_name;
 
     // if we have a second argument, set a custom kiss message
-    char* kiss;
-    if (argc >= 3)
-        kiss = argv[2];
-    else
-        kiss = "*mwah*";
+    char kiss[32] = "*mwah*";
+    if (argc >= 3) {
+        int len = strlen(argv[2]);
+        int written_chars = 0;
+        for (int i = 0; i < len; i++) {
+            if (written_chars >= 31) {
+                kiss[31] = '\0';
+                break;
+            };
+            if (iscntrl(argv[2][i])) continue;
+            kiss[i] = argv[2][i];
+            written_chars++;
+        }
+    }
     
     bool kissed = false;
     // iterate over all files in directory