qdev-monitor: print help to stdout

qdev_device_help() is used from command line "-device help", or from
HMP "device_add". If used from command line, print help to stdout
(it is only printed on explicit demand).

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>

include/monitor/monitor.h

@@ -47,4 +47,7 @@ int monitor_fdset_dup_fd_add(int64_t fdset_id, int dup_fd);
 void monitor_fdset_dup_fd_remove(int dup_fd);
 int monitor_fdset_dup_fd_find(int dup_fd);
 
+void monitor_vfprintf(FILE *stream,
+                      const char *fmt, va_list ap) GCC_FMT_ATTR(2, 0);
+
 #endif /* MONITOR_H */

monitor.c

@@ -4493,19 +4493,29 @@ static void monitor_readline_flush(void *opaque)
 }
 
 /*
- * Print to current monitor if we have one, else to stderr.
+ * Print to current monitor if we have one, else to stream.
  * TODO should return int, so callers can calculate width, but that
  * requires surgery to monitor_vprintf().  Left for another day.
  */
-void error_vprintf(const char *fmt, va_list ap)
+void monitor_vfprintf(FILE *stream, const char *fmt, va_list ap)
 {
     if (cur_mon && !monitor_cur_is_qmp()) {
         monitor_vprintf(cur_mon, fmt, ap);
     } else {
-        vfprintf(stderr, fmt, ap);
+        vfprintf(stream, fmt, ap);
     }
 }
 
+/*
+ * Print to current monitor if we have one, else to stderr.
+ * TODO should return int, so callers can calculate width, but that
+ * requires surgery to monitor_vprintf().  Left for another day.
+ */
+void error_vprintf(const char *fmt, va_list ap)
+{
+    monitor_vfprintf(stderr, fmt, ap);
+}
+
 void error_vprintf_unless_qmp(const char *fmt, va_list ap)
 {
     if (cur_mon && !monitor_cur_is_qmp()) {

qdev-monitor.c

@@ -104,22 +104,31 @@ static bool qdev_class_has_alias(DeviceClass *dc)
     return (qdev_class_get_alias(dc) != NULL);
 }
 
+static void out_printf(const char *fmt, ...)
+{
+    va_list ap;
+
+    va_start(ap, fmt);
+    monitor_vfprintf(stdout, fmt, ap);
+    va_end(ap);
+}
+
 static void qdev_print_devinfo(DeviceClass *dc)
 {
-    error_printf("name \"%s\"", object_class_get_name(OBJECT_CLASS(dc)));
+    out_printf("name \"%s\"", object_class_get_name(OBJECT_CLASS(dc)));
     if (dc->bus_type) {
-        error_printf(", bus %s", dc->bus_type);
+        out_printf(", bus %s", dc->bus_type);
     }
     if (qdev_class_has_alias(dc)) {
-        error_printf(", alias \"%s\"", qdev_class_get_alias(dc));
+        out_printf(", alias \"%s\"", qdev_class_get_alias(dc));
     }
     if (dc->desc) {
-        error_printf(", desc \"%s\"", dc->desc);
+        out_printf(", desc \"%s\"", dc->desc);
     }
     if (!dc->user_creatable) {
-        error_printf(", no-user");
+        out_printf(", no-user");
     }
-    error_printf("\n");
+    out_printf("\n");
 }
 
 static void qdev_print_devinfos(bool show_no_user)
@@ -155,8 +164,7 @@ static void qdev_print_devinfos(bool show_no_user)
                 continue;
             }
             if (!cat_printed) {
-                error_printf("%s%s devices:\n", i ? "\n" : "",
-                             cat_name[i]);
+                out_printf("%s%s devices:\n", i ? "\n" : "", cat_name[i]);
                 cat_printed = true;
             }
             qdev_print_devinfo(dc);
@@ -278,13 +286,11 @@ int qdev_device_help(QemuOpts *opts)
     }
 
     for (prop = prop_list; prop; prop = prop->next) {
-        error_printf("%s.%s=%s", driver,
-                     prop->value->name,
-                     prop->value->type);
+        out_printf("%s.%s=%s", driver, prop->value->name, prop->value->type);
         if (prop->value->has_description) {
-            error_printf(" (%s)\n", prop->value->description);
+            out_printf(" (%s)\n", prop->value->description);
         } else {
-            error_printf("\n");
+            out_printf("\n");
         }
     }