char: error out if given unhandled size options

This is a small help, because in fact all combined chardev
options are accepted by qemu_chardev_opts[]. But given that a user may
legitimately want to use the size options with a VC backend, we can
report an error when we know the backend doesn't support it.

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

chardev/char.c

@@ -639,6 +639,18 @@ ChardevBackend *qemu_chr_parse_opts(QemuOpts *opts, Error **errp)
         return NULL;
     }
 
+    if (!cc->supports_size_opts) {
+        const char * const invalid_opts[] = {
+            "width", "height", "cols", "rows", NULL
+        };
+
+        if (qemu_opt_has_any(opts, invalid_opts)) {
+            error_setg(errp, "chardev '%s' does not support size options",
+                       qemu_opts_id(opts));
+            return NULL;
+        }
+    }
+
     backend = g_new0(ChardevBackend, 1);
     backend->type = CHARDEV_BACKEND_KIND_NULL;
 

include/chardev/char.h

@@ -254,6 +254,7 @@ struct ChardevClass {
 
     bool internal; /* TODO: eventually use TYPE_USER_CREATABLE */
     bool supports_yank;
+    bool supports_size_opts;
 
     /* parse command line options and populate QAPI @backend */
     void (*chr_parse)(QemuOpts *opts, ChardevBackend *backend, Error **errp);

include/qemu/option.h

@@ -73,6 +73,7 @@ struct QemuOptsList {
 
 const char *qemu_opt_get(QemuOpts *opts, const char *name);
 char *qemu_opt_get_del(QemuOpts *opts, const char *name);
+bool qemu_opt_has_any(QemuOpts *opts, const char * const *names);
 /**
  * qemu_opt_has_help_opt:
  * @opts: options to search for a help request

ui/console-vc.c

@@ -1251,6 +1251,7 @@ static void char_vc_class_init(ObjectClass *oc, const void *data)
     cc->chr_write = vc_chr_write;
     cc->chr_accept_input = vc_chr_accept_input;
     cc->chr_set_echo = vc_chr_set_echo;
+    cc->supports_size_opts = true;
 }
 
 static const TypeInfo char_vc_type_info = {

util/qemu-option.c

@@ -271,6 +271,19 @@ const char *qemu_opt_get(QemuOpts *opts, const char *name)
     return opt->str;
 }
 
+bool qemu_opt_has_any(QemuOpts *opts, const char * const *names)
+{
+    int it;
+
+    for (it = 0; names[it]; it++) {
+        if (qemu_opt_get(opts, names[it])) {
+            return true;
+        }
+    }
+    return false;
+}
+
+
 void qemu_opt_iter_init(QemuOptsIter *iter, QemuOpts *opts, const char *name)
 {
     iter->opts = opts;