expanded error detection for scroll button option

Now the scroll_button will not accept:
  - letters on string beginning;
  - negative numbers.

What is tolerated:
  - letters after number;
  - rational numbers: the fraction after dot will be omitted.

1 files changed, 8 insertions, 2 deletions

diff --git a/sway/commands/input/scroll_button.c b/sway/commands/input/scroll_button.c
index d19f3516..6345b71b 100644
--- a/sway/commands/input/scroll_button.c
+++ b/sway/commands/input/scroll_button.c
@@ -18,11 +18,17 @@ struct cmd_results *input_cmd_scroll_button(int argc, char **argv) {
         struct input_config *new_config =
                 new_input_config(current_input_config->identifier);
 
-        int scroll_button = atoi(argv[0]);
+        char *endptr;
+        long scroll_button = strtol(*argv, &endptr, 10);
+        if (endptr == *argv && scroll_button == 0) {
+                free_input_config(new_config);
+                return cmd_results_new(CMD_INVALID, "scroll_button",
+                                "Scroll button identifier must be an integer.");
+        }
         if (scroll_button < 0) {
                 free_input_config(new_config);
                 return cmd_results_new(CMD_INVALID, "scroll_button",
-                                "Scroll button identifier cannot be negative");
+                                "Scroll button identifier cannot be negative.");
         }
         new_config->scroll_button = scroll_button;