BlueZ源代码阅读：Bluetoothd启动分析

1. Initialize structure main_opts, set its pagable and connectable, also set its default name;
2. Parse the command line options;
3. Check if single instance, otherwise exit;
5. Create and bind HCI socket server;
6. Load main.conf options;
7. Call g_io_add_watch to add io channels;
8. Get D-Bus system path;
9. Register to the D-Bus system bus;
10. Start SDP server;
    1. initialize SDP server;
       Register the public browse group root;
       Register SDP server’s service record;
       Creating L2CAP socket server l2cap_sock;
       Create local unix socket unix_sock;
    2. Register device id;
    3. Add watch io_accept_event to l2cap_sock;
    4. Add watch io_accept_event to unix_sock;
11. set_service_classes_callback(update_service_classes);
12. Load plugins;
13. Add watch io_stack_event to the handle of main_opts.sock;
14. Initialze already connected services;
15. Enter message loops{…};
16. Unregister D-bus;
17. Clean up plugins;
18. Stop SDP server;
19. Release other resources;