Question

void device_added()
{
     printf("Added \n");
     g_main_loop_quit (loop);
}

void device_removed()
{
     printf("Removed\n");
     g_main_loop_quit (loop);
}

int
main (int argc, char **argv)
{
  DBusGConnection *connection;
  DBusMessage* message;
  GError *error;
  DBusGProxy *proxy;
  char **name_list;
  char **name_list_ptr;
  gchar *m1;
  gchar *m2;

  g_type_init ();

  error = NULL;
  connection = dbus_g_bus_get(DBUS_BUS_SYSTEM,NULL);

  if (connection == NULL)
    {
      g_printerr ("Failed to open connection to bus: %s\n",
                  error->message);
      g_error_free (error);
      exit (1);
    }


  /* Create a proxy object for the "bus driver" (name "org.freedesktop.DBus") */
     proxy=dbus_g_proxy_new_for_name(connection,"org.freedesktop.UDisks","/org/freedesktop/UDisks","org.freedesktop.UDisks");

     if(proxy == NULL)
     {
        g_printerr ("Failed To Create A proxy...: %s\n", error->message);
        g_error_free (error);
        exit(1);
     }
     else
       printf("Probably got a connection to the correct interface...\n");


     m1=g_cclosure_marshal_VOID__STRING;
     m2=g_cclosure_marshal_VOID__STRING;

     dbus_g_object_register_marshaller(m1,G_TYPE_BOOLEAN,G_TYPE_STRING,G_TYPE_INVALID);

     dbus_g_object_register_marshaller(m2,G_TYPE_BOOLEAN,G_TYPE_STRING,G_TYPE_INVALID);

     dbus_g_proxy_add_signal(proxy,"DeviceAdded",G_TYPE_INVALID);
     dbus_g_proxy_add_signal(proxy,"DeviceRemoved",G_TYPE_INVALID);

     dbus_g_proxy_connect_signal(proxy,"DeviceAdded",(GCallback)device_added,NULL,NULL);

     dbus_g_proxy_connect_signal(proxy,"DeviceRemoved",(GCallback)device_removed,NULL,NULL);

     loop=g_main_loop_new(NULL,FALSE);

     g_main_loop_run (loop);

     return 0;
}

我想检测usb事件，我正在使用来自org.freedesktop.UDisks接口的DeviceAdded和DeviceRemoved信号。但是device_added或device_removed没有调用，有人可以告诉我上面的代码有什么问题吗？

Answer 1

/*
Compile using the command 
 * gcc -o dbus-usb dbus-usb.c `pkg-config --libs --cflags dbus-glib-1`
*/
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <dbus/dbus.h>
#include <dbus/dbus-glib.h>
#include <glib.h>
#include <glib-object.h>

static GMainLoop *loop;

static void
device_added (DBusGProxy *proxy,
         char *ObjectPath[],
         char *word_eol[],
         guint hook_id,
         guint context_id,
         gpointer user_data)
{
    g_debug("\nAdded a New Device:\nObjectPath: %s\nhook_id: %d\ncontext_id: %d\nuser_data: %d\n", (char*)ObjectPath, hook_id, context_id, (int)user_data); 
}


static void
device_removed (DBusGProxy *proxy,
         char *ObjectPath[],
         char *word_eol[],
         guint hook_id,
         guint context_id,
         gpointer user_data)
{
    g_debug("\nRemoved Device\nObjectPath: %s\nhook_id: %d\ncontext_id: %d\nuser_data: %d\n", (char*)ObjectPath, hook_id, context_id, (int)user_data); 
}

int
main (int argc, char **argv)
{
  DBusGConnection *connection;
  DBusMessage* message;
  GError *error;
  DBusGProxy *proxy;
  gchar *m1;
  gchar *m2;
  char *object_path;
  GPtrArray* ret;

  g_type_init ();

  error = NULL;
  connection = dbus_g_bus_get(DBUS_BUS_SYSTEM,NULL);

  if (connection == NULL)
    {
      g_printerr ("Failed to open connection to bus: %s\n",
                  error->message);
      g_error_free (error);
      exit (1);
    }
    else
    {
        printf("Got a connection to DBUS_BUS_SYSTEM\n");
    }


  /* Create a proxy object for the "bus driver" (name "org.freedesktop.DBus") */

     proxy=dbus_g_proxy_new_for_name(connection,"org.freedesktop.UDisks","/org/freedesktop/UDisks","org.freedesktop.UDisks");

     if(proxy == NULL)
     {
        g_printerr ("Failed To Create A proxy...: %s\n", error->message);
        g_error_free (error);
        exit(1);
     }
     else
       printf("Probably got a connection to the correct interface...\n");
//It works for me without marsheller register, add and connect to the signals directly
     m1=g_cclosure_marshal_VOID__STRING;
     m2=g_cclosure_marshal_VOID__STRING;

     dbus_g_object_register_marshaller(m1,G_TYPE_NONE,G_TYPE_STRING,G_TYPE_INVALID);

     dbus_g_object_register_marshaller(m2,G_TYPE_NONE,G_TYPE_STRING,G_TYPE_INVALID);

     dbus_g_proxy_add_signal(proxy,"DeviceAdded",DBUS_TYPE_G_OBJECT_PATH, G_TYPE_INVALID);
     dbus_g_proxy_connect_signal(proxy,"DeviceAdded",(GCallback)device_added,NULL,NULL);

     dbus_g_proxy_add_signal(proxy,"DeviceRemoved",DBUS_TYPE_G_OBJECT_PATH, G_TYPE_INVALID);
     dbus_g_proxy_connect_signal(proxy,"DeviceRemoved",(GCallback)device_removed,NULL,NULL);

     loop=g_main_loop_new(NULL,FALSE);

     g_main_loop_run (loop);

     g_error_free (error);

     return 0;
}

ABove代码正常工作并且能够检测Ubuntu pc上的usb事件，主要变化是dbus_g_proxy_add_signal函数的DBUS_TYPE_G_OBJECT_PATH参数，而不是G_TYPE_STRING。

但是如果我为ARM架构交叉编译并在ARM板上执行相同的操作，我又面临同样的问题

Answer 2

在启动两个

之后我也开始使用ARM了

dbus-daemon --system

和

/usr/libexec/udisks-daemon

dbus glib绑定UDisks错误

2 个答案: