【问题标题】:Bluez programming on C on dbusdbus 上 C 上的 Bluez 编程
【发布时间】:2019-02-24 08:39:35
【问题描述】:

我正在编写一个简单的代理应用程序。

我可以配对我的设备,但是当我尝试连接时(点击连接选项)它失败并显示以下 dbus 日志

我们将非常感谢您的帮助。

method call time=1537417845.746765 sender=:1.0 -> destination=:1.25 serial=2824 path=/org/bluez/AutoPinAgent; interface=org.bluez.Agent1; member=AuthorizeService
   object path "/org/bluez/hci0/dev_00_00_00_17_55_B8"
   string "00001108-0000-1000-8000-00805f9b34fb"
error time=1537417845.749340 sender=:1.25 -> destination=:1.0 error_name=org.freedesktop.DBus.Error.UnknownMethod reply_serial=2824
   string "No such interface 'org.bluez.Agent1' on object at path /org/bluez/AutoPinAgent"

【问题讨论】:

    标签: c dbus bluez


    【解决方案1】:

    如果没有代理的源代码以及您尝试连接的方式,真的很难判断。从日志中可以清楚地看出,当守护进程尝试连接 HSP 配置文件的 HS(headset) 角色时,它是通过调用您的代理的AuthorizeService 来请求授权。

    从错误回复中,我了解到您没有向 Bluez 正确注册方法/接口。因此,您需要实现AuthorizeService 并在此配置文件尝试连接时授权服务。

    以下是实现 Bluez 的 doc/agent-api.txt 的 Agent 示例。所以你需要根据你的需要在这个例子中实现AuthorizeService。本例只是模板代码,没有具体实现。

    /*
     * gcc `pkg-config --cflags glib-2.0 gio-2.0` -Wall -Wextra -o ./bin/agent ./agent.c `pkg-config --libs glib-2.0 gio-2.0`
     */
    #include <glib.h>
    #include <gio/gio.h>
    #include <stdio.h>
    
    GMainLoop *loop;
    GDBusConnection *con;
    #define AGENT_PATH  "/org/bluez/AutoPinAgent"
    
    static void bluez_agent_method_call(GDBusConnection *conn,
                        const gchar *sender,
                        const gchar *path,
                        const gchar *interface,
                        const gchar *method,
                        GVariant *params,
                        GDBusMethodInvocation *invocation,
                        void *userdata)
    {
        int pass;
        int entered;
        char *opath;
        GVariant *p= g_dbus_method_invocation_get_parameters(invocation);
    
        g_print("Agent method call: %s.%s()\n", interface, method);
        if(!strcmp(method, "RequestPinCode")) {
            ;
        }
        else if(!strcmp(method, "DisplayPinCode")) {
            ;
        }
        else if(!strcmp(method, "RequestPasskey")) {
            g_print("Getting the Pin from user: ");
            fscanf(stdin, "%d", &pass);
            g_print("\n");
            g_dbus_method_invocation_return_value(invocation, g_variant_new("(u)", pass));
        }
        else if(!strcmp(method, "DisplayPasskey")) {
            g_variant_get(params, "(ouq)", &opath, &pass, &entered);
            g_dbus_method_invocation_return_value(invocation, NULL);
        }
        else if(!strcmp(method, "RequestConfirmation")) {
            g_variant_get(params, "(ou)", &opath, &pass);
            g_dbus_method_invocation_return_value(invocation, NULL);
        }
        else if(!strcmp(method, "RequestAuthorization")) {
            ;
        }
        else if(!strcmp(method, "AuthorizeService")) {
            ;
        }
        else if(!strcmp(method, "Cancel")) {
            ;
        }
        else
            g_print("We should not come here, unknown method\n");
    }
    
    static const GDBusInterfaceVTable agent_method_table = {
        .method_call = bluez_agent_method_call,
    };
    
    int bluez_register_agent(GDBusConnection *con)
    {
        GError *error = NULL;
        guint id = 0;
        GDBusNodeInfo *info = NULL;
    
        static const gchar bluez_agent_introspection_xml[] =
            "<node name='/org/bluez/SampleAgent'>"
            "   <interface name='org.bluez.Agent1'>"
            "       <method name='Release'>"
            "       </method>"
            "       <method name='RequestPinCode'>"
            "           <arg type='o' name='device' direction='in' />"
            "           <arg type='s' name='pincode' direction='out' />"
            "       </method>"
            "       <method name='DisplayPinCode'>"
            "           <arg type='o' name='device' direction='in' />"
            "           <arg type='s' name='pincode' direction='in' />"
            "       </method>"
            "       <method name='RequestPasskey'>"
            "           <arg type='o' name='device' direction='in' />"
            "           <arg type='u' name='passkey' direction='out' />"
            "       </method>"
            "       <method name='DisplayPasskey'>"
            "           <arg type='o' name='device' direction='in' />"
            "           <arg type='u' name='passkey' direction='in' />"
            "           <arg type='q' name='entered' direction='in' />"
            "       </method>"
            "       <method name='RequestConfirmation'>"
            "           <arg type='o' name='device' direction='in' />"
            "           <arg type='u' name='passkey' direction='in' />"
            "       </method>"
            "       <method name='RequestAuthorization'>"
            "           <arg type='o' name='device' direction='in' />"
            "       </method>"
            "       <method name='AuthorizeService'>"
            "           <arg type='o' name='device' direction='in' />"
            "           <arg type='s' name='uuid' direction='in' />"
            "       </method>"
            "       <method name='Cancel'>"
            "       </method>"
            "   </interface>"
            "</node>";
    
        info = g_dbus_node_info_new_for_xml(bluez_agent_introspection_xml, &error);
        if(error) {
            g_printerr("Unable to create node: %s\n", error->message);
            g_clear_error(&error);
            return 0;
        }
    
        id = g_dbus_connection_register_object(con, 
                AGENT_PATH,
                info->interfaces[0],
                &agent_method_table,
                NULL, NULL, &error);
        g_dbus_node_info_unref(info);
        //g_dbus_connection_unregister_object(con, id);
        /* call register method in AgentManager1 interface */
        return id;
    }
    
    static int bluez_agent_call_method(const gchar *method, GVariant *param)
    {
        GVariant *result;
        GError *error = NULL;
    
        result = g_dbus_connection_call_sync(con,
                "org.bluez",
                "/org/bluez",
                "org.bluez.AgentManager1",
                method,
                param,
                NULL,
                G_DBUS_CALL_FLAGS_NONE,
                -1,
                NULL,
                &error);
        if(error != NULL) {
            g_print("Register %s: %s\n", AGENT_PATH, error->message);
            return 1;
        }
    
        g_variant_unref(result);
        return 0;
    }
    
    static int bluez_register_autopair_agent(const char *cap)
    {
        int rc;
    
        rc = bluez_agent_call_method("RegisterAgent", g_variant_new("(os)", AGENT_PATH, cap));
        if(rc)
            return 1;
    
        rc = bluez_agent_call_method("RequestDefaultAgent", g_variant_new("(o)", AGENT_PATH));
        if(rc) {
            bluez_agent_call_method("UnregisterAgent", g_variant_new("(o)", AGENT_PATH));
            return 1;
        }
    
        return 0;
    }
    
    
    static void cleanup_handler(int signo)
    {
        if (signo == SIGINT) {
            g_print("received SIGINT\n");
            g_main_loop_quit(loop);
        }
    }
    
    int main(int argc, char **argv)
    {
        int id;
        int rc;
    
        if(argc < 2)
            return 1;
    
        if(signal(SIGINT, cleanup_handler) == SIG_ERR)
            g_print("can't catch SIGINT\n");
    
        con = g_bus_get_sync(G_BUS_TYPE_SYSTEM, NULL, NULL);
        if(con == NULL) {
            g_print("Not able to get connection to system bus\n");
            return 1;
        }
    
        loop = g_main_loop_new(NULL, FALSE);
    
        id = bluez_register_agent(con);
        if(id == 0)
            goto fail;
    
        rc = bluez_register_autopair_agent(argv[1]);
        if(rc) {
            g_print("Not able to register default autopair agent\n");
            goto fail;
        }
    
        g_main_loop_run(loop);
    
    fail:
        g_dbus_connection_unregister_object(con, id);
        g_object_unref(con);
        return 0;
    }
    

    在编写我们自己的源代码之前,最好先从 bluetoothctl 基于 CLI 的配对和连接开始。

    【讨论】:

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