monitor: Create QAPIfied monitor_init()

This adds a new QAPI-based monitor_init() function. The existing
monitor_init_opts() is rewritten to simply put its QemuOpts parameter
into a visitor and pass the resulting QAPI object to monitor_init().

This will cause some change in those error messages for the monitor
options in the system emulator that are now generated by the visitor
rather than explicitly checked in monitor_init_opts().

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20200224143008.13362-17-kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

include/monitor/monitor.h

@@ -7,6 +7,7 @@
 
 extern __thread Monitor *cur_mon;
 typedef struct MonitorHMP MonitorHMP;
+typedef struct MonitorOptions MonitorOptions;
 
 #define QMP_REQ_QUEUE_LEN_MAX 8
 
@@ -18,6 +19,7 @@ void monitor_init_globals(void);
 void monitor_init_globals_core(void);
 void monitor_init_qmp(Chardev *chr, bool pretty);
 void monitor_init_hmp(Chardev *chr, bool use_readline);
+int monitor_init(MonitorOptions *opts, Error **errp);
 int monitor_init_opts(QemuOpts *opts, Error **errp);
 void monitor_cleanup(void);
 

monitor/monitor.c

@@ -25,7 +25,9 @@
 #include "qemu/osdep.h"
 #include "monitor-internal.h"
 #include "qapi/error.h"
+#include "qapi/opts-visitor.h"
 #include "qapi/qapi-emit-events.h"
+#include "qapi/qapi-visit-control.h"
 #include "qapi/qmp/qdict.h"
 #include "qapi/qmp/qstring.h"
 #include "qemu/error-report.h"
@@ -609,50 +611,55 @@ void monitor_init_globals_core(void)
                                    NULL);
 }
 
-int monitor_init_opts(QemuOpts *opts, Error **errp)
+int monitor_init(MonitorOptions *opts, Error **errp)
 {
     Chardev *chr;
-    bool qmp;
-    bool pretty = false;
-    const char *chardev;
-    const char *mode;
 
-    mode = qemu_opt_get(opts, "mode");
-    if (mode == NULL) {
-        mode = "readline";
-    }
-    if (strcmp(mode, "readline") == 0) {
-        qmp = false;
-    } else if (strcmp(mode, "control") == 0) {
-        qmp = true;
-    } else {
-        error_setg(errp, "unknown monitor mode \"%s\"", mode);
-        return -1;
-    }
-
-    if (!qmp && qemu_opt_get(opts, "pretty")) {
-        warn_report("'pretty' is deprecated for HMP monitors, it has no effect "
-                    "and will be removed in future versions");
-    }
-    if (qemu_opt_get_bool(opts, "pretty", 0)) {
-        pretty = true;
-    }
-
-    chardev = qemu_opt_get(opts, "chardev");
-    if (!chardev) {
-        error_report("chardev is required");
-        exit(1);
-    }
-    chr = qemu_chr_find(chardev);
+    chr = qemu_chr_find(opts->chardev);
     if (chr == NULL) {
-        error_setg(errp, "chardev \"%s\" not found", chardev);
+        error_setg(errp, "chardev \"%s\" not found", opts->chardev);
         return -1;
     }
 
-    if (qmp) {
-        monitor_init_qmp(chr, pretty);
-    } else {
+    switch (opts->mode) {
+    case MONITOR_MODE_CONTROL:
+        monitor_init_qmp(chr, opts->pretty);
+        break;
+    case MONITOR_MODE_READLINE:
+        if (opts->pretty) {
+            warn_report("'pretty' is deprecated for HMP monitors, it has no "
+                        "effect and will be removed in future versions");
+        }
         monitor_init_hmp(chr, true);
+        break;
+    default:
+        g_assert_not_reached();
+    }
+
+    return 0;
+}
+
+int monitor_init_opts(QemuOpts *opts, Error **errp)
+{
+    Visitor *v;
+    MonitorOptions *options;
+    Error *local_err = NULL;
+
+    v = opts_visitor_new(opts);
+    visit_type_MonitorOptions(v, NULL, &options, &local_err);
+    visit_free(v);
+
+    if (local_err) {
+        goto out;
+    }
+
+    monitor_init(options, &local_err);
+    qapi_free_MonitorOptions(options);
+
+out:
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return -1;
     }
     return 0;
 }

qapi/control.json

@@ -216,3 +216,39 @@
 # <- { "return": {} }
 ##
 { 'command': 'quit' }
+
+##
+# @MonitorMode:
+#
+# An enumeration of monitor modes.
+#
+# @readline: HMP monitor (human-oriented command line interface)
+#
+# @control: QMP monitor (JSON-based machine interface)
+#
+# Since: 5.0
+##
+{ 'enum': 'MonitorMode', 'data': [ 'readline', 'control' ] }
+
+##
+# @MonitorOptions:
+#
+# Options to be used for adding a new monitor.
+#
+# @id:          Name of the monitor
+#
+# @mode:        Selects the monitor mode (default: readline)
+#
+# @pretty:      Enables pretty printing (QMP only)
+#
+# @chardev:     Name of a character device to expose the monitor on
+#
+# Since: 5.0
+##
+{ 'struct': 'MonitorOptions',
+  'data': {
+      '*id': 'str',
+      '*mode': 'MonitorMode',
+      '*pretty': 'bool',
+      'chardev': 'str'
+  } }