Add qemu_opts_validate() for post parsing validation

Several qemu command line options have a parameter whose value affects
what other parameters are accepted for the option.

In these cases, we can have an empty description table in the
QemuOptsList and once the option has been parsed we can use a suitable
description table to validate the other parameters based on the value of
that parameter.
Signed-off-by: NMark McLoughlin <markmc@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

qemu-option.c

@@ -778,6 +778,39 @@ QemuOpts *qemu_opts_parse(QemuOptsList *list, const char *params, const char *fi
     return opts;
 }
 
+/* Validate parsed opts against descriptions where no
+ * descriptions were provided in the QemuOptsList.
+ */
+int qemu_opts_validate(QemuOpts *opts, QemuOptDesc *desc)
+{
+    QemuOpt *opt;
+
+    assert(opts->list->desc[0].name == NULL);
+
+    QTAILQ_FOREACH(opt, &opts->head, next) {
+        int i;
+
+        for (i = 0; desc[i].name != NULL; i++) {
+            if (strcmp(desc[i].name, opt->name) == 0) {
+                break;
+            }
+        }
+        if (desc[i].name == NULL) {
+            fprintf(stderr, "option \"%s\" is not valid for %s\n",
+                    opt->name, opts->list->name);
+            return -1;
+        }
+
+        opt->desc = &desc[i];
+
+        if (qemu_opt_parse(opt) < 0) {
+            return -1;
+        }
+    }
+
+    return 0;
+}
+
 int qemu_opts_foreach(QemuOptsList *list, qemu_opts_loopfunc func, void *opaque,
                       int abort_on_failure)
 {

qemu-option.h

@@ -115,6 +115,7 @@ int qemu_opts_set(QemuOptsList *list, const char *id,
                   const char *name, const char *value);
 const char *qemu_opts_id(QemuOpts *opts);
 void qemu_opts_del(QemuOpts *opts);
+int qemu_opts_validate(QemuOpts *opts, QemuOptDesc *desc);
 int qemu_opts_do_parse(QemuOpts *opts, const char *params, const char *firstname);
 QemuOpts *qemu_opts_parse(QemuOptsList *list, const char *params, const char *firstname);