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ubus是openwrt用来实现进程间通信的一种消息总线机制，其数据格式类似json。守护进程dbusd以server/client的方式统一管理进程间的通信，进程可以通过ubus向其他进程发送数据 调用服务,或则向dbus订阅特定消息。

1. ubus中每个对象都用路径(object path)的方式来表达, 命令ubus list 可以列出所有注册对象:

 root@Widora:/# ubus list
 dhcp
 iwinfo
 log
 network
 network.device
 network.interface
 network.interface.lan
 network.interface.loopback
 network.wireless
 rpc-sys
 service
 session
 system
 uci

2. 加上-v选项可以看到指定对象可调用的具体方法(method):

 root@Widora:/# ubus list network.interface.lan -v
 'network.interface.lan' @3fcd0eda
         "up":{}
         "down":{}
         "status":{}
         "prepare":{}
         "dump":{}
         "add_device":{"name":"String","link-ext":"Boolean"}
         "remove_device":{"name":"String","link-ext":"Boolean"}
         "notify_proto":{}
         "remove":{}
         "set_data":{}

3. 调用对象方法的时候ubus会向特定对象发送方法名和参数, 对象接收到后会返回要求的状态数据或执行结果。 比如调用network.wireless对象status方法(无需参数), 会返回无线网络的状态：

 root@Widora:/# ubus call network.wireless status
 {
      "radio0": {
              "up": true,
              "pending": false,
              "autostart": true,
              "disabled": false,
              "config": {
                      "variant": "mt7628",
                      "country": "CN",
                      "hwmode": "11bgn",
                      "htmode": "HT20",
                      "channel": "auto",
                      "disabled": false
              },
              "interfaces": [
                      {
                              "section": "ap",
                              "ifname": "ra0",
                              "config": {
                                      "mode": "ap",
                                      "ifname": "ra0",
                                      "ssid": "Widora-86D9",
   ... ...
 }