Simplify argument parsing of vmctl stop

The previous argument parsing logic had at least three bugs:
a copy-paste error led to an off-by-one and a printf "%s" NULL,
as reported by Preben Guldberg.  A previous commit led to a dead
else branch and a use of uninitialized.  This can all be avoided
by reworking the logic so as to be readable.

Prompted by a diff from Preben

ok dv

diff --git a/usr.sbin/vmctl/main.c b/usr.sbin/vmctl/main.c
index 249eaa3..6eac8ee 100644 (file)
--- a/usr.sbin/vmctl/main.c
+++ b/usr.sbin/vmctl/main.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: main.c,v 1.62 2020/01/03 05:32:00 pd Exp $    */
+/*     $OpenBSD: main.c,v 1.63 2021/03/26 16:28:15 tb Exp $    */
 
 /*
  * Copyright (c) 2015 Reyk Floeter <reyk@openbsd.org>
@@ -927,7 +927,7 @@ ctl_start(struct parse_result *res, int argc, char *argv[])
 int
 ctl_stop(struct parse_result *res, int argc, char *argv[])
 {
-       int              ch, ret;
+       int              ch;
 
        while ((ch = getopt(argc, argv, "afw")) != -1) {
                switch (ch) {
@@ -948,20 +948,15 @@ ctl_stop(struct parse_result *res, int argc, char *argv[])
        argc -= optind;
        argv += optind;
 
-       if (argc == 0) {
-               if (res->action != CMD_STOPALL)
+       if (res->action == CMD_STOPALL) {
+               if (argc != 0)
                        ctl_usage(res->ctl);
-       } else if (argc > 1)
-               ctl_usage(res->ctl);
-       else if (argc == 1)
-               ret = parse_vmid(res, argv[0], 0);
-       else
-               ret = -1;
-
-       /* VM id is only expected without the -a flag */
-       if ((res->action != CMD_STOPALL && ret == -1) ||
-           (res->action == CMD_STOPALL && ret != -1))
-               errx(1, "invalid id: %s", argv[1]);
+       } else {
+               if (argc != 1)
+                       ctl_usage(res->ctl);
+               if (parse_vmid(res, argv[0], 0) == -1)
+                       errx(1, "invalid id: %s", argv[0]);
+       }
 
        return (vmmaction(res));
 }