ubuntu 下dbus的环境搭建和使用

从https://launchpad.net/ubuntu/+source/dbus/1.10.6-1ubuntu2下载需要的dbus包，然后解压，./configure make && make install

client.c

1. #include <stdio.h>
2. #include <stdlib.h>
3. #include <dbus/dbus.h>
4. #include <unistd.h>
5.  
6. const int RES_SUCCESS = -1;
7. const int RES_FAILED  = 0;
8.  
9. int my_dbus_initialization(char const * _bus_name, DBusConnection ** _conn) {
10.     DBusError err;
11.  
12.     int ret;
13.  
14.     dbus_error_init(&err);
15.  
16.     *_conn = dbus_bus_get(DBUS_BUS_SESSION, &err);
17.     if(dbus_error_is_set(&err)) {
18.         printf("Connection Error ");
19.         dbus_error_free(&err);
20.         return RES_FAILED;
21.     }
22.  
23.     ret = dbus_bus_request_name(*_conn, _bus_name, DBUS_NAME_FLAG_REPLACE_EXISTING, &err);
24.     if(dbus_error_is_set(&err)){
25.         printf("Requece name error ");
26.         dbus_error_free(&err);
27.         return RES_FAILED;
28.     }
29.  
30.     if(DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER != ret) {
31.         return RES_FAILED;
32.     }
33.  
34.     return RES_SUCCESS;
35. }
36.  
37. int my_dbus_send_sigal(DBusConnection * conn) {
38.     dbus_uint32_t serial = 0;
39.     DBusMessage* msg;
40.     DBusMessageIter args;
41.     char sigvalue[20] = "liyiwen";
42.  
43.     msg = dbus_message_new_signal("/test/signal/Object",  // object name
44.         "test.signal.Type",     // interface name
45.         "Test");                // name of signal
46.  
47.     if (NULL == msg) {
48.         printf("Message Null");
49.         return RES_FAILED;
50.     }
51.  
52.     dbus_message_iter_init_append(msg, &args);
53.  
54.     printf("%s ", sigvalue);
55.     dbus_uint32_t my_age = 10;
56.     if(!dbus_message_iter_append_basic(&args, DBUS_TYPE_UINT32, &my_age)) {
57.         printf("Out of memory ");
58.         return RES_FAILED;
59.     }
60.  
61.     if(!dbus_connection_send(conn, msg, &serial)) {
62.         printf("Out of memory");
63.         return RES_FAILED;
64.     }
65.     dbus_connection_flush(conn);
66.  
67.     dbus_message_unref(msg);
68.  
69.     return RES_SUCCESS;
70.  
71. }
72.  
73. int main(int agrc, char** argv)
74. {
75.     DBusConnection * conn;
76.  
77.     printf("Start ");
78.     if (RES_FAILED == my_dbus_initialization("test.method.client", &conn)) {
79.         exit(1);
80.     }
81.     my_dbus_send_sigal(conn);
82.  
83.     while(1){sleep(10);}
84.  
85.     return 0;
86. }
88. sercer.c
89. 1. #include <stdio.h>
    2. #include <stdlib.h>
    3. #include <dbus/dbus.h>
    4. #include <unistd.h>
    5.  
    6. const int RES_SUCCESS = -1;
    7. const int RES_FAILED  = 0;
    8.  
    9. int my_dbus_initialization(char const * _bus_name, DBusConnection **_conn) {
    10.     DBusError err;
    11.     int ret;
    12.  
    13.     dbus_error_init(&err);
    14.  
    15.     *_conn = dbus_bus_get(DBUS_BUS_SESSION, &err);
    16.     if(dbus_error_is_set(&err)) {
    17.         printf("Connection Error(%s) ", err.message);
    18.         dbus_error_free(&err);
    19.         return RES_FAILED;
    20.     }
    21.  
    22.     ret = dbus_bus_request_name(*_conn, _bus_name, DBUS_NAME_FLAG_REPLACE_EXISTING, &err);
    23.     if(dbus_error_is_set(&err)){
    24.         printf("Requece name error(%s) ", err.message);
    25.         dbus_error_free(&err);
    26.         return RES_FAILED;
    27.     }
    28.     if(DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER != ret) {
    29.         return RES_FAILED;
    30.     }
    31.     return RES_SUCCESS;
    32. }
    33.  
    34. int main(int agrc, char** argv)
    35. {
    36.  
    37.     DBusError err;
    38.     DBusMessage* msg;
    39.     DBusMessageIter args;
    40.  
    41.     dbus_error_init(&err);
    42.     DBusConnection *conn;
    43.     if (RES_FAILED == my_dbus_initialization("test.method.server", &conn)) {
    44.         exit(1);
    45.     }
    46.  
    47.     dbus_bus_add_match(conn, "type='signal', interface='test.signal.Type'", &err);
    48.  
    49.     dbus_connection_flush(conn);
    50.     if(dbus_error_is_set(&err)) {
    51.         printf("dbus_bus_add_match err (%s)", err.message);
    52.         return RES_FAILED;
    53.     }
    54.  
    55.     while(1) {
    56.         dbus_connection_read_write(conn, 0);
    57.         msg = dbus_connection_pop_message(conn);
    58.  
    59.         if(NULL == msg) {
    60.             sleep(1);
    61.             continue;
    62.         }
    63.  
    64.         if(dbus_message_is_signal(msg, "test.signal.Type", "Test")) {
    65.             if(!dbus_message_iter_init(msg, &args)) {
    66.                 printf("dbus_message_iter_init error, msg has no arguments! ");
    67.             }
    68.             else if (DBUS_TYPE_UINT32 != dbus_message_iter_get_arg_type(&args)){
    69.                 printf("not a uint 32 type ! ");
    70.             }
    71.             else {
    72.                 dbus_uint32_t my_age = 0;
    73.                 dbus_message_iter_get_basic(&args, &my_age);
    74.                 printf("Got signal with value %d ", my_age);
    75.             }
    76.         }
    77.  
    78.         dbus_message_unref(msg);
    79.  
    80.     }
    81.  
    82.     return 0;
    83. }
    85. 1. http://dbus.freedesktop.org/doc/dbus-specification.html  这当然是最权威最重要的资料，但我觉得不是一个很好的入门资料。
        2. http://dbus.freedesktop.org/doc/dbus-tutorial.html 这里面有一些不错的例子，对Names 的解释也很好，但用的是 glib 的 binding，不能探究更底层的动作一度还是让我云里雾里。
        3. http://dbus.freedesktop.org/doc/api/html/group__DBusMessage.html  DBus 的 C 编程接口的在线文档，非常棒也非常有用
        4. http://dbus.freedesktop.org/doc/dbus/libdbus-tutorial.html 如何用 C API 层面的 DBus ，相见恨晚。