dbus参考代码--在一个dbus方法中调用另外一个dbus服务端提供的方法

ゝ一纸荒年。 2022-02-26 09:54 579阅读 1赞

这是在网上的代码基础上修改的，主要是项目中用到了**[dbus][]**的嵌套调用，所以写了测试代码。贴出来供参考。

转载请注明：[http://blog.csdn.net/shanzhizi][http_blog.csdn.net_shanzhizi]

/********************************************************************************/ 
    /*
    * Example low-level D-Bus code.
    * Written by Matthew Johnson <dbus@matthew.ath.cx>
    *
    * This code has been released into the Public Domain.
    * You may do whatever you like with it.
    */
    #include <dbus/dbus.h>
    #include <stdbool.h>
    #include <unistd.h>
    #include <stdio.h>
    #include <stdlib.h> 
    
    DBusConnection* g_conn;
    /**http://blog.csdn.net/shanzhizi
    * Connect to the DBUS bus and send a broadcast signal
    */
    void sendsignal(char* sigvalue)
    {
       DBusMessage* msg;
       DBusMessageIter args;
       DBusConnection* conn;
       DBusError err;
       int ret;
       dbus_uint32_t serial = 0; 
       printf("Sending signal with value %s\n", sigvalue); 
       // initialise the error value
       dbus_error_init(&err); 
       // connect to the DBUS system bus, and check for errors
       conn = dbus_bus_get(DBUS_BUS_SYSTEM, &err);
       if (dbus_error_is_set(&err)) { 
          fprintf(stderr, "Connection Error (%s)\n", err.message); 
          dbus_error_free(&err); 
       }
       if (NULL == conn) { 
          exit(1); 
       } 
       // register our name on the bus, and check for errors
       ret = dbus_bus_request_name(conn, "test.signal.source", DBUS_NAME_FLAG_REPLACE_EXISTING , &err);
       if (dbus_error_is_set(&err)) { 
          fprintf(stderr, "Name Error (%s)\n", err.message); 
          dbus_error_free(&err); 
       }
       if (DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER != ret) { 
          exit(1);
       } 
       // create a signal & check for errors 
       msg = dbus_message_new_signal("/test/signal/Object", // object name of the signal
                                     "test.signal.Type",    // interface name of the signal
                                     "Test");               // name of the signal
       if (NULL == msg) 
       { 
          fprintf(stderr, "Message Null\n"); 
          exit(1); 
       } 
       // append arguments onto signal
       dbus_message_iter_init_append(msg, &args);
       if (!dbus_message_iter_append_basic(&args, DBUS_TYPE_STRING, &sigvalue)) {
          fprintf(stderr, "Out Of Memory!\n"); 
          exit(1);
       } 
       // send the message and flush the connection
       if (!dbus_connection_send(conn, msg, &serial)) {
          fprintf(stderr, "Out Of Memory!\n"); 
          exit(1);
       }
       dbus_connection_flush(conn);
       
       printf("Signal Sent\n");
       
       // free the message 
       dbus_message_unref(msg);
    } 
    
    
    /**
    * Call a method on a remote object
    */
    void query(char* param) 
    {
       DBusMessage* msg;
       DBusMessageIter args;
       DBusConnection* conn;
       DBusError err;
       DBusPendingCall* pending;
       int ret;
       char *stat = "";
       dbus_uint32_t level; 
       printf("Calling remote method with %s\n", param); 
       // initialiset the errors
       dbus_error_init(&err); 
       // connect to the system bus and check for errors
       conn = dbus_bus_get(DBUS_BUS_SYSTEM, &err);
       if (dbus_error_is_set(&err)) { 
          fprintf(stderr, "Connection Error (%s)\n", err.message); 
          dbus_error_free(&err);
       }
       if (NULL == conn) { 
          exit(1); 
       } 
       // request our name on the bus
       ret = dbus_bus_request_name(conn, "ws.method.cgi", DBUS_NAME_FLAG_REPLACE_EXISTING , &err);
       if (dbus_error_is_set(&err)) { 
          fprintf(stderr, "Name Error (%s)\n", err.message); 
          dbus_error_free(&err);
       }
       if (DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER != ret) { 
          exit(1);
       } 
       // create a new method call and check for errors
       msg = dbus_message_new_method_call("ws.method.listen",// target for the method call
                                          "/ws/method/object", // object to call on
                                          "ws.method.Type",    // interface to call on
                                          "Method");             // method name
       if (NULL == msg) { 
          fprintf(stderr, "Message Null\n");
          exit(1);
       } 
       // append arguments
       dbus_message_iter_init_append(msg, &args);
       if (!dbus_message_iter_append_basic(&args, DBUS_TYPE_STRING, ¶m)) {
          fprintf(stderr, "Out Of Memory!\n"); 
          exit(1);
       }
       
       // send message and get a handle for a reply
       if (!dbus_connection_send_with_reply (conn, msg, &pending, -1)) { // -1 is default timeout
          fprintf(stderr, "Out Of Memory!\n"); 
          exit(1);
       }
       if (NULL == pending) { 
          fprintf(stderr, "Pending Call Null\n"); 
          exit(1); 
       }
       dbus_connection_flush(conn);
       
       printf("Request Sent\n");
       
       // free message
       dbus_message_unref(msg);
       
       // block until we recieve a reply
       dbus_pending_call_block(pending); 
       // get the reply message
       msg = dbus_pending_call_steal_reply(pending);
       if (NULL == msg) {
          fprintf(stderr, "Reply Null\n"); 
          exit(1); 
       }
       // free the pending message handle
       dbus_pending_call_unref(pending); 
       // read the parameters
       if (!dbus_message_iter_init(msg, &args))
          fprintf(stderr, "Message has no arguments!\n"); 
       else if (DBUS_TYPE_STRING != dbus_message_iter_get_arg_type(&args)) 
          fprintf(stderr, "Argument is not boolean!\n"); 
       else
          dbus_message_iter_get_basic(&args, &stat); 
       if (!dbus_message_iter_next(&args))
          fprintf(stderr, "Message has too few arguments!\n"); 
       else if (DBUS_TYPE_UINT32 != dbus_message_iter_get_arg_type(&args)) 
          fprintf(stderr, "Argument is not int!\n"); 
       else
          dbus_message_iter_get_basic(&args, &level); 
       printf("Got Reply: %s, %d\n", stat, level);
       
       // free reply 
       dbus_message_unref(msg);   
    } 
    
    
    
    
    /**http://blog.csdn.net/shanzhizi
    * Call a method on a remote object
    */
    void igmp_query(DBusConnection* conn,char* param) 
    {
    	DBusMessage* msg;
       DBusMessageIter args;
       DBusPendingCall* pending;
       int ret;
       char *stat="";
       dbus_uint32_t level; 
    
       // create a new method call and check for errors
       msg = dbus_message_new_method_call("ws.method.igmp",// target for the method call
                                          "/ws/method/object", // object to call on
                                          "ws.method.Type",    // interface to call on
                                          "Method");             // method name
       if (NULL == msg) { 
          fprintf(stderr, "Message Null\n");
          exit(1);
       } 
       // append arguments
       dbus_message_iter_init_append(msg, &args);
       if (!dbus_message_iter_append_basic(&args, DBUS_TYPE_STRING, ¶m)) {
          fprintf(stderr, "Out Of Memory!\n"); 
          exit(1);
       }
       
       // send message and get a handle for a reply
       if (!dbus_connection_send_with_reply (conn, msg, &pending, -1)) { // -1 is default timeout
          fprintf(stderr, "Out Of Memory!\n"); 
          exit(1);
       }
       if (NULL == pending) { 
          fprintf(stderr, "Pending Call Null\n"); 
          exit(1); 
       }
       dbus_connection_flush(conn);
       
       printf("igmp Request Sent\n");
       
       // free message
       dbus_message_unref(msg);
       
       // block until we recieve a reply
       dbus_pending_call_block(pending); 
       // get the reply message
       msg = dbus_pending_call_steal_reply(pending);
       if (NULL == msg) {
          fprintf(stderr, "Reply Null\n"); 
          exit(1); 
       }
       // free the pending message handle
       dbus_pending_call_unref(pending); 
       // read the parameters
       if (!dbus_message_iter_init(msg, &args))
          fprintf(stderr, "Message has no arguments!\n"); 
       else if (DBUS_TYPE_STRING != dbus_message_iter_get_arg_type(&args)) 
          fprintf(stderr, "Argument is not boolean!\n"); 
       else
          dbus_message_iter_get_basic(&args, &stat); 
       if (!dbus_message_iter_next(&args))
          fprintf(stderr, "Message has too few arguments!\n"); 
       else if (DBUS_TYPE_UINT32 != dbus_message_iter_get_arg_type(&args)) 
          fprintf(stderr, "Argument is not int!\n"); 
       else
          dbus_message_iter_get_basic(&args, &level); 
       printf("Got Reply: %s, %d\n", stat, level);
       
       // free reply 
       dbus_message_unref(msg);   
    } 
    
    
    DBusMessage		*reply_to_method_call(DBusMessage* msg, void *user_data)
    {
       DBusMessage* reply;
       DBusMessageIter args;
       bool stat = true;
       dbus_uint32_t level = 10;
       dbus_uint32_t serial = 0;
       char* param = ""; 
       char returnstr[30]="cgi server return";
       char *ssparam = returnstr;
       // read the arguments
       if (!dbus_message_iter_init(msg, &args))
          fprintf(stderr, "Message has no arguments!\n"); 
       else if (DBUS_TYPE_STRING != dbus_message_iter_get_arg_type(&args)) 
          fprintf(stderr, "Argument is not string!\n"); 
       else 
          dbus_message_iter_get_basic(&args, ¶m); 
          
       printf("Method called with %s\n", param); 
    igmp_query(g_conn,"igmp");     
       // create a reply from the message
       reply = dbus_message_new_method_return(msg); 
       // add the arguments to the reply
       /*dbus_message_iter_init_append(reply, &args);
       if (!dbus_message_iter_append_basic(&args, DBUS_TYPE_STRING, &ssparam)) { 
          fprintf(stderr, "Out Of Memory!\n"); 
          exit(1);
       }
       printf("******************\n");
       if (!dbus_message_iter_append_basic(&args, DBUS_TYPE_UINT32, &level)) { 
          fprintf(stderr, "Out Of Memory!\n"); 
          exit(1);
       } */
       
       dbus_message_append_args (reply,
                                    DBUS_TYPE_STRING,&ssparam,
                                    DBUS_TYPE_UINT32,&level,
                                    DBUS_TYPE_INVALID);
                                    
                                    return reply;
    
    } 
    
    DBusHandlerResult ws_dbus_message_handler_listen(DBusConnection *connection, DBusMessage *message, void *user_data)
    {
        DBusMessage		*reply = NULL;
        const char * path =dbus_message_get_path(message);
        if(NULL==path){
            return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
        }
        if (strcmp(path,"/ws/method/object") == 0) {
        /*syslog_ax_dbus_dbg("npd obj path"WS_DBUS_METHOD_OBJPATH"\r\n");*/
            if (dbus_message_is_method_call(message,"ws.method.Type","Method")) {
            	reply = reply_to_method_call(message,user_data);
            }else{
                printf("unknown method call\n");
            }
        }else{
    			printf("unknown path call\n");;
        }
        
        if(reply){
                   // send the reply && flush the connection
               if (!dbus_connection_send(connection, reply, NULL)) {
                    return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
               }
               dbus_connection_flush(connection);
               // free the reply
               dbus_message_unref(reply);
    
            return DBUS_HANDLER_RESULT_HANDLED ;
        }else{
            return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
        }
    }
    
    
    DBusMessage		*reply_to_method_call_igmp(DBusMessage* msg, void *user_data)
    {
       DBusMessage* reply;
       DBusMessageIter args;
       bool stat = true;
       dbus_uint32_t level = 20;
       dbus_uint32_t serial = 0;
       char* param = ""; 
       char returnstr[30]="igmp server return";
       char *ssparam = returnstr;
       // read the arguments
       if (!dbus_message_iter_init(msg, &args))
          fprintf(stderr, "Message has no arguments!\n"); 
       else if (DBUS_TYPE_STRING != dbus_message_iter_get_arg_type(&args)) 
          fprintf(stderr, "Argument is not string!\n"); 
       else 
          dbus_message_iter_get_basic(&args, ¶m); 
          
       printf("Method called with %s\n", param); 
     
       // create a reply from the message
       reply = dbus_message_new_method_return(msg); 
       // add the arguments to the reply
       /*dbus_message_iter_init_append(reply, &args);
       if (!dbus_message_iter_append_basic(&args, DBUS_TYPE_STRING, &ssparam)) { 
          fprintf(stderr, "Out Of Memory!\n"); 
          exit(1);
       }
       printf("******************\n");
       if (!dbus_message_iter_append_basic(&args, DBUS_TYPE_UINT32, &level)) { 
          fprintf(stderr, "Out Of Memory!\n"); 
          exit(1);
       } */
       dbus_message_append_args (reply,
                                    DBUS_TYPE_STRING,&ssparam,
                                    DBUS_TYPE_UINT32,&level,
                                    DBUS_TYPE_INVALID);
                                    
                                    return reply;
    
    } 
    DBusHandlerResult ws_dbus_message_handler_igmp(DBusConnection *connection, DBusMessage *message, void *user_data)
    {
        DBusMessage		*reply = NULL;
        const char * path =dbus_message_get_path(message);
        if(NULL==path){
            return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
        }
        if (strcmp(path,"/ws/method/object") == 0) {
        /*syslog_ax_dbus_dbg("npd obj path"WS_DBUS_METHOD_OBJPATH"\r\n");*/
            if (dbus_message_is_method_call(message,"ws.method.Type","Method")) {
            	reply = reply_to_method_call_igmp(message,user_data);
            }else{
                printf("unknown method call\n");
            }
        }else{
    			printf("unknown path call\n");
        }
        
        if(reply){
                   // send the reply && flush the connection
               if (!dbus_connection_send(connection, reply, NULL)) {
                    return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
               }
               dbus_connection_flush(connection);
               // free the reply
               dbus_message_unref(reply);
    
            return DBUS_HANDLER_RESULT_HANDLED ;
        }else{
            return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
        }
    }
    
    
    /**
    * Server that exposes a method call and waits for it to be called
    */
    void listen() 
    {
       DBusMessage* msg;
       DBusMessage* reply;
       DBusMessageIter args;
       //DBusConnection* conn;
       DBusError err;
       int ret;
       char* param; 
       printf("Listening for method calls\n"); 
       // initialise the error
       dbus_error_init(&err);
       
       // connect to the bus and check for errors
       g_conn = dbus_bus_get(DBUS_BUS_SYSTEM, &err);
       if (dbus_error_is_set(&err)) { 
          fprintf(stderr, "Connection Error (%s)\n", err.message); 
          dbus_error_free(&err); 
       }
       if (NULL == g_conn) {
          fprintf(stderr, "Connection Null\n"); 
          exit(1); 
       }
       
       // request our name on the bus and check for errors
       ret = dbus_bus_request_name(g_conn, "ws.method.listen", 
                                   DBUS_NAME_FLAG_REPLACE_EXISTING , &err);
       if (dbus_error_is_set(&err)) { 
          fprintf(stderr, "Name Error (%s)\n", err.message); 
          dbus_error_free(&err);
       }
       if (DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER != ret) { 
          fprintf(stderr, "Not Primary Owner (%d)\n", ret);
          exit(1); 
       } 
       // loop, testing for new messages
       /*while (true) {
          // non blocking read of the next available message
          dbus_connection_read_write(conn, -1);
          msg = dbus_connection_pop_message(conn); 
          // loop again if we haven't got a message
          if (NULL == msg) { 
             sleep(1); 
             continue; 
          }
          
          // check this is a method call for the right interface & method
          if (dbus_message_is_method_call(msg, "test.method.Type", "Method"))
          {
          	igmp_query(conn,"igmp");
             reply_to_method_call(msg, conn,"daemon return",201); 
          }
          // free the message
          dbus_message_unref(msg);
       }*/
       
        // 设置处理消息的函数  56:  
          if (!dbus_connection_add_filter (g_conn, ws_dbus_message_handler_listen, NULL, NULL)) { 
                    return;  
         }  
          // 分派消息的Loop 
           while (dbus_connection_read_write_dispatch (g_conn, -1))  
                sleep(0);
    } 
    
    
    
    /**
    * Server that exposes a method call and waits for it to be called
    */
    void listen_igmp() 
    {
       DBusMessage* msg;
       DBusMessage* reply;
       DBusMessageIter args;
       DBusConnection* conn;
       DBusError err;
       int ret;
       char* param; 
       printf("Listening for method calls\n"); 
       // initialise the error
       dbus_error_init(&err);
       
       // connect to the bus and check for errors
       conn = dbus_bus_get(DBUS_BUS_SYSTEM, &err);
       if (dbus_error_is_set(&err)) { 
          fprintf(stderr, "Connection Error (%s)\n", err.message); 
          dbus_error_free(&err); 
       }
       if (NULL == conn) {
          fprintf(stderr, "Connection Null\n"); 
          exit(1); 
       }
       
       // request our name on the bus and check for errors
       ret = dbus_bus_request_name(conn, "ws.method.igmp", 
                                   DBUS_NAME_FLAG_REPLACE_EXISTING , &err);
       if (dbus_error_is_set(&err)) { 
          fprintf(stderr, "Name Error (%s)\n", err.message); 
          dbus_error_free(&err);
       }
       if (DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER != ret) { 
          fprintf(stderr, "Not Primary Owner (%d)\n", ret);
          exit(1); 
       } 
       // 设置处理消息的函数  56:  
          if (!dbus_connection_add_filter (conn, ws_dbus_message_handler_igmp, NULL, NULL)) { 
                    return;  
         }  
          // 分派消息的Loop 
           while (dbus_connection_read_write_dispatch (conn, -1))  
                sleep(0);
    } 
    
    
    
    
    /**
    * Listens for signals on the bus
    */
    void receive()
    {
       DBusMessage* msg;
       DBusMessageIter args;
       DBusConnection* conn;
       DBusError err;
       int ret;
       char* sigvalue; 
       printf("Listening for signals\n"); 
       // initialise the errors
       dbus_error_init(&err);
       
       // connect to the bus and check for errors
       conn = dbus_bus_get(DBUS_BUS_SYSTEM, &err);
       if (dbus_error_is_set(&err)) { 
          fprintf(stderr, "Connection Error (%s)\n", err.message);
          dbus_error_free(&err); 
       }
       if (NULL == conn) { 
          exit(1);
       }
       
       // request our name on the bus and check for errors
       ret = dbus_bus_request_name(conn, "test.signal.sink", DBUS_NAME_FLAG_REPLACE_EXISTING , &err);
       if (dbus_error_is_set(&err)) { 
          fprintf(stderr, "Name Error (%s)\n", err.message);
          dbus_error_free(&err); 
       }
       if (DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER != ret) {
          exit(1);
       } 
       // add a rule for which messages we want to see
       dbus_bus_add_match(conn, "type='signal',interface='test.signal.Type'", &err); // see signals from the given interface
       dbus_connection_flush(conn);
       if (dbus_error_is_set(&err)) { 
          fprintf(stderr, "Match Error (%s)\n", err.message);
          exit(1); 
       }
       printf("Match rule sent\n"); 
       // loop listening for signals being emmitted
       while (true) { 
          // non blocking read of the next available message
          dbus_connection_read_write(conn, 0);
          msg = dbus_connection_pop_message(conn); 
          // loop again if we haven't read a message
          if (NULL == msg) { 
             sleep(1);
             continue;
          } 
          // check if the message is a signal from the correct interface and with the correct name
          if (dbus_message_is_signal(msg, "test.signal.Type", "Test")) {
             
             // read the parameters
             if (!dbus_message_iter_init(msg, &args))
                fprintf(stderr, "Message Has No Parameters\n");
             else if (DBUS_TYPE_STRING != dbus_message_iter_get_arg_type(&args)) 
                fprintf(stderr, "Argument is not string!\n"); 
             else
                dbus_message_iter_get_basic(&args, &sigvalue);
             
             printf("Got Signal with value %s\n", sigvalue);
          } 
          // free the message
          dbus_message_unref(msg);
       }
    } 
      
      
      
    int main(int argc, char** argv)
    {
     char* param = "no param"; 
     printf("#Kluter T1:argc=%d\n", argc);
     if (2 > argc) 
     {
          printf ("Syntax: dbus-example [send|receive|listen|query] [<param>]\n");
          return 1;
       } 
       
     if (3 >= argc && NULL != argv[2]) 
      param = argv[2]; 
     if (0 == strcmp(argv[1], "send"))
      sendsignal(param);
     else if (0 == strcmp(argv[1], "receive"))
      receive();
     else if (0 == strcmp(argv[1], "listen"))
      listen();
     else if (0 == strcmp(argv[1], "query"))
      query(param);
      else if(0 == strcmp(argv[1]),"listen_igmp")
      	listen_igmp();
     else 
     {
      printf ("Syntax: dbus-example [send|receive|listen|query] [<param>]\n");
      return 1;
     }
     return 0;
    } 
    /****************************************************************************/

[dbus]: http://blog.csdn.net/shanzhizi/article/category/1185201
[http_blog.csdn.net_shanzhizi]: http://blog.csdn.net/shanzhizi