QemuOpts: dump config.

Add a function to write the QemuOpts configuration to a git-style
config file.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

qemu-config.c

@@ -257,3 +257,42 @@ int qemu_set_option(const char *str)
     return 0;
 }
 
+struct ConfigWriteData {
+    QemuOptsList *list;
+    FILE *fp;
+};
+
+static int config_write_opt(const char *name, const char *value, void *opaque)
+{
+    struct ConfigWriteData *data = opaque;
+
+    fprintf(data->fp, "  %s = \"%s\"\n", name, value);
+    return 0;
+}
+
+static int config_write_opts(QemuOpts *opts, void *opaque)
+{
+    struct ConfigWriteData *data = opaque;
+    const char *id = qemu_opts_id(opts);
+
+    if (id) {
+        fprintf(data->fp, "[%s \"%s\"]\n", data->list->name, id);
+    } else {
+        fprintf(data->fp, "[%s]\n", data->list->name);
+    }
+    qemu_opt_foreach(opts, config_write_opt, data, 0);
+    fprintf(data->fp, "\n");
+    return 0;
+}
+
+void qemu_config_write(FILE *fp)
+{
+    struct ConfigWriteData data = { .fp = fp };
+    int i;
+
+    fprintf(fp, "# qemu config file\n\n");
+    for (i = 0; lists[i] != NULL; i++) {
+        data.list = lists[i];
+        qemu_opts_foreach(data.list, config_write_opts, &data, 0);
+    }
+}

qemu-config.h

@@ -10,4 +10,6 @@ extern QemuOptsList qemu_rtc_opts;
 
 int qemu_set_option(const char *str);
 
+void qemu_config_write(FILE *fp);
+
 #endif /* QEMU_CONFIG_H */