蓝牙！你为什么搜索不到设备？
蓝牙（Bluetooth）是一种无线通讯协议，其名Bluetooth来自于十世纪丹麦国王哈拉尔 HaralBluetooth，最先由英特尔的工程师 Jim Kardach在1997的一个无线通信行业的会议上，提出使用“Bluetooth”作为无线通讯技术标准的名称，随后Bluetooth这个名字便一直沿用至今；20多年过去了，随着科技的进步与发展，在这片蓝色的星球上，覆盖面积极为广阔的“蓝色”已经不止是水资源了，“蓝牙”也应该算是其中的一份子。
从蓝牙耳机、蓝牙键盘/鼠标到物联网，当我们享受蓝牙这项技术带来便利的同时，它也给我们带来各种“罢工”的难题；不巧的是，现在GDK8就遇到了；如下图所示，当你打开蓝牙去搜索设备的时候，会发现它找不出来任何一个设备。
罢工归罢工，想让它再开始为我们“工作”，也只能一步一步的，去解决问题了！
初步试探
先输入rfkill，查看一下对应的信息。
输入hciconfig -a，看一下蓝牙设备详细信息；它确实已经开启了，但就是搜索不到设备。
试探性的输入一下hcitool scan；不出意外，找不出任何一个设备（没有低级错误，绝对开启其他的蓝牙设备了，保证正常的蓝牙能搜到）。
考虑一小会，配置蓝牙应该需要配置相应的配置文件，于是感觉打开main.conf文件一看（见下图），好家伙！全被注释掉了，莫非就是配置文件的问题？
这好像找到了答案，于是赶紧找到一台能搜到蓝牙设备的机器，查看它的配置文件；可惜，问题没有这么好解决，那里面的配置文件也是全部注释掉的；白高兴一场！
回过劲来，转念一想，之前GDK8的WiFI有问题是dts文件写的有问题，莫非蓝牙这次也是，把设备的dts转储出来，再和好用的机器的一比较，果然啊！！！就是这样！！！
它们一样的。。。。。。
在经过上面试探性的解决失败后，只能考虑使用调试器了。
编译bluez源代码
在上调试器之前，先到https://packages.ubuntu.com/impish/bluez 网站去下载bluez的源代码。
如果想要搜索ubuntu的其他包可以到这个网站去下载（https://packages.ubuntu.com/ ），或者浏览器直接搜索ubuntu packages也行。
下载完成后，先准备编译一下源代码；这主要是有两个目的，一是别以前的程序有什么Bug没有改，然后换新编译后的就可以了，二是生成一个具有调试符号的程序，这样也方便我们后续去查看问题。
先看一下readme文件，里面还是很贴心的给出了bluez依赖的东西、配置和编译的命令，当然还有相关的说明；可以看到readme里面的配置命令没有加–g的选项，但我们为了调试的需求，要把–g和–enable-debug给加上。
在GDK8上面D-Bus（library）、udev library（optional）、readline（command line clients）应该都是没有的，需要安装一下；具体安装步骤如下。
1. sudo apt-get update
2. sudo apt --fix-broken install
3. sudo apt install libdbus-1-dev
4. sudo apt install libudev-dev
5. sudo apt install libical-dev
6. sudo apt install libreadline-dev
7. sudo apt-get install python-docutils进入bluez-5.48目录下，输入./configure --g --enable-debug --prefix=/usr --mandir=/usr/share/man --sysconfdir=/etc --localstatedir=/var；不输错应该就没有什么问题；正确的话，就如下图所示。
编译时间大概是11：02
执行sudo su切换至root用户，输入sudo make && make install命令；如下图所示。
假如已经sudo了或root下make时遇到权限问题，应该给对应的脚本（make会提示你的）加上可执行权限 [chmod +x]。
此时我们输入file ./src/bluetooth，可以看到可执行文件是有符号的（1：with debug info；2.no stripped，如果查看一个没有符号的文件，那么就会看到stripped）
stripped：将程序中的符号信息剔除掉了。
not stripped：保留了程序中的符号信息。
查看调试支持
在bluez的源代码里面可以看到下面的关于DBG定义，它们是用于输出调试信息的。
#define DBG_IDX(idx, fmt, arg...) do { \
static struct btd_debug_desc __btd_debug_desc \
__attribute__((used, section("__debug"), aligned(8))) = { \
.file = __FILE__, .flags = BTD_DEBUG_FLAG_DEFAULT, \
}; \
if (__btd_debug_desc.flags & BTD_DEBUG_FLAG_PRINT) \
btd_debug(idx, "%s:%s() " fmt, __FILE__, __func__ , ## arg); \
} while (0)
#define DBG(fmt, arg...) DBG_IDX(0xffff, fmt, ## arg)我们可以在btd_debug_desc结构体内看到里面存储着文件名和标志位。
struct btd_debug_desc {
const char *file;
#define BTD_DEBUG_FLAG_DEFAULT (0)
#define BTD_DEBUG_FLAG_PRINT (1 << 0)
unsigned int flags;
} __attribute__((aligned(8)));至于是否打印这些信息，则会根据btd_debug_desc内的标志位信息进行判断。
关于上面的东西，光纸上谈兵当然不行，还要“格物”一下，才可以理解更加深刻；所以立马就打开调试器去看一下。
首先在命令行输入sudo gdb --args /usr/lib/bluetooth/bluetoothd -n -d（bluetoothd的位置一般是这个，如果不是，可以自行去查找其位置在哪里）。
-n: 在后台不做为服务运行。
-d: 输出调试信息
想要获得调试信息，有两种方法可以；一是设置-d参数，二是在源代码内修改BTD_DEBUG_FLAG_DEFAULT标志位（1：debug 0：no debug），除此之外，也可以在调试过程中手动修改BTD_DEBUG_FLAG_DEFAULT标志
更多参数及说明可以参考链接：https://linux.die.net/man/8/bluetoothd
从下面的对比中，可以很明显的看到有没有-d选项时，输出信息的数量的差异是非常巨大的。
有-d选项：
(gdb) r
Starting program: /usr/lib/bluetooth/bluetoothd -n -d
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/aarch64-linux-gnu/libthread_db.so.1".
bluetoothd[1015]: Bluetooth daemon 5.62
bluetoothd[1015]: src/main.c:parse_config() parsing /etc/bluetooth/main.conf
bluetoothd[1015]: src/main.c:parse_config() Key file does not have key “DiscoverableTimeout” in group “General”
bluetoothd[1015]: src/main.c:parse_config() Key file does not have key “AlwaysPairable” in group “General”
bluetoothd[1015]: src/main.c:parse_config() Key file does not have key “PairableTimeout” in group “General”
bluetoothd[1015]: src/main.c:parse_config() Key file does not have key “Privacy” in group “General”
bluetoothd[1015]: src/main.c:parse_config() Key file does not have key “JustWorksRepairing” in group “General”
bluetoothd[1015]: src/main.c:parse_config() Key file does not have key “TemporaryTimeout” in group “General”
bluetoothd[1015]: src/main.c:parse_config() Key file does not have key “Name” in group “General”
bluetoothd[1015]: src/main.c:parse_config() Key file does not have key “Class” in group “General”
bluetoothd[1015]: src/main.c:parse_config() Key file does not have key “DeviceID” in group “General”
bluetoothd[1015]: src/main.c:parse_config() Key file does not have key “ReverseServiceDiscovery” in group “General”
bluetoothd[1015]: src/main.c:parse_config() Key file does not have group “GATT”
bluetoothd[1015]: src/main.c:parse_config() Key file does not have group “GATT”
bluetoothd[1015]: src/main.c:parse_config() Key file does not have group “GATT”
bluetoothd[1015]: src/main.c:parse_config() Key file does not have group “GATT”
bluetoothd[1015]: src/main.c:parse_config() Key file does not have group “AVDTP”
bluetoothd[1015]: src/main.c:parse_config() Key file does not have group “AVDTP”
bluetoothd[1015]: src/main.c:parse_config() Key file does not have group “AdvMon”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “BR”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “BR”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “BR”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “BR”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “BR”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “BR”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “BR”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “BR”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “BR”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “BR”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “LE”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “LE”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “LE”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “LE”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “LE”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “LE”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “LE”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “LE”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “LE”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “LE”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “LE”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “LE”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “LE”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “LE”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “LE”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “LE”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “LE”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “LE”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “LE”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “LE”
bluetoothd[1015]: src/main.c:parse_mode_config() Key file does not have group “LE”
bluetoothd[1015]: src/adapter.c:adapter_init() sending read version command
bluetoothd[1015]: Starting SDP server
bluetoothd[1015]: src/sdpd-service.c:register_device_id() Adding device id record for 0002:1d6b:0246:053e
bluetoothd[1015]: src/plugin.c:plugin_init() Loading builtin plugins
bluetoothd[1015]: src/plugin.c:add_plugin() Loading hostname plugin
bluetoothd[1015]: src/plugin.c:add_plugin() Loading wiimote plugin
bluetoothd[1015]: src/plugin.c:add_plugin() Loading autopair plugin
bluetoothd[1015]: src/plugin.c:add_plugin() Loading policy plugin
bluetoothd[1015]: src/plugin.c:add_plugin() Loading a2dp plugin
bluetoothd[1015]: src/plugin.c:add_plugin() Loading avrcp plugin
bluetoothd[1015]: src/plugin.c:add_plugin() Loading network plugin
bluetoothd[1015]: src/plugin.c:add_plugin() Loading input plugin
bluetoothd[1015]: src/plugin.c:add_plugin() Loading hog plugin
bluetoothd[1015]: src/plugin.c:add_plugin() Loading gap plugin
bluetoothd[1015]: src/plugin.c:add_plugin() Loading scanparam plugin
bluetoothd[1015]: src/plugin.c:add_plugin() Loading deviceinfo plugin
bluetoothd[1015]: src/plugin.c:add_plugin() Loading battery plugin
bluetoothd[1015]: src/plugin.c:plugin_init() Loading plugins /usr/lib/bluetooth/plugins
bluetoothd[1015]: profiles/input/suspend-none.c:suspend_init()
bluetoothd[1015]: profiles/network/manager.c:read_config() /etc/bluetooth/network.conf: Key file does not have key “DisableSecurity” in group “General”
bluetoothd[1015]: profiles/network/manager.c:read_config() Config options: Security=true
bluetoothd[1015]: profiles/network/bnep.c:bnep_init() kernel lacks bnep-protocol support
bluetoothd[1015]: src/plugin.c:plugin_init() System does not support network plugin
bluetoothd[1015]: src/main.c:main() Entering main loop
bluetoothd[1015]: src/rfkill.c:rfkill_event() RFKILL event idx 0 type 2 op 0 soft 0 hard 0
bluetoothd[1015]: Bluetooth management interface 1.10 initialized
bluetoothd[1015]: src/adapter.c:read_version_complete() sending read supported commands command
bluetoothd[1015]: src/adapter.c:read_version_complete() sending read index list command
bluetoothd[1015]: src/rfkill.c:rfkill_event() RFKILL event idx 1 type 1 op 0 soft 0 hard 0
bluetoothd[1015]: src/rfkill.c:rfkill_event() RFKILL event idx 2 type 1 op 0 soft 0 hard 0
bluetoothd[1015]: src/adapter.c:read_commands_complete() Number of commands: 61
bluetoothd[1015]: src/adapter.c:read_commands_complete() Number of events: 34
bluetoothd[1015]: src/adapter.c:read_commands_complete() enabling kernel-side connection control
bluetoothd[1015]: src/rfkill.c:rfkill_event() RFKILL event idx 3 type 2 op 0 soft 0 hard 0
bluetoothd[1015]: src/adapter.c:read_index_list_complete() Number of controllers: 1
bluetoothd[1015]: src/adapter.c:read_index_list_complete() Found index 0
bluetoothd[1015]: src/adapter.c:index_added() index 0
bluetoothd[1015]: src/adapter.c:reset_adv_monitors() sending remove Adv Monitor command with handle 0
bluetoothd[1015]: src/adapter.c:btd_adapter_new() System name: BlueZ 5.62
bluetoothd[1015]: src/adapter.c:btd_adapter_new() Major class: 0
bluetoothd[1015]: src/adapter.c:btd_adapter_new() Minor class: 0
bluetoothd[1015]: src/adapter.c:btd_adapter_new() Modalias: usb:v1D6Bp0246d053E
bluetoothd[1015]: src/adapter.c:btd_adapter_new() Discoverable timeout: 180 seconds
bluetoothd[1015]: src/adapter.c:btd_adapter_new() Pairable timeout: 0 seconds
bluetoothd[1015]: src/adapter.c:index_added() sending read info command for index 0
bluetoothd[1015]: src/adapter.c:reset_adv_monitors_complete() Failed to reset Adv Monitors: Unknown Command (0x01)
bluetoothd[1015]: src/adapter.c:read_info_complete() index 0 status 0x00
bluetoothd[1015]: src/adapter.c:clear_uuids() sending clear uuids command for index 0
bluetoothd[1015]: src/adapter.c:clear_devices() sending clear devices command for index 0
bluetoothd[1015]: src/adapter.c:set_privacy() sending set privacy command for index 0
bluetoothd[1015]: src/adapter.c:set_privacy() setting privacy mode 0x00 for index 0
bluetoothd[1015]: src/gatt-database.c:btd_gatt_database_new() GATT Manager registered for adapter: /org/bluez/hci0
bluetoothd[1015]: src/adapter.c:adapter_service_add() /org/bluez/hci0
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Adding record with handle 0x10001
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000007-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000100-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001002-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001800-0000-1000-8000-00805f9
bluetoothd[1015]: src/adapter.c:adapter_service_insert() /org/bluez/hci0
bluetoothd[1015]: src/adapter.c:add_uuid() sending add uuid command for index 0
bluetoothd[1015]: src/adapter.c:adapter_service_add() /org/bluez/hci0
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Adding record with handle 0x10002
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000007-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000100-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001002-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001801-0000-1000-8000-00805f9
bluetoothd[1015]: src/adapter.c:adapter_service_insert() /org/bluez/hci0
bluetoothd[1015]: src/adapter.c:add_uuid() sending add uuid command for index 0
bluetoothd[1015]: src/adapter.c:adapter_service_add() /org/bluez/hci0
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Adding record with handle 0x10003
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000007-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000100-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001002-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 0000180a-0000-1000-8000-00805f9
bluetoothd[1015]: src/adapter.c:adapter_service_insert() /org/bluez/hci0
bluetoothd[1015]: src/adapter.c:add_uuid() sending add uuid command for index 0
bluetoothd[1015]: src/advertising.c:btd_adv_manager_new() LE Advertising Manager created for adapter: /org/bluez/hci0
bluetoothd[1015]: profiles/audio/a2dp.c:media_server_probe() path /org/bluez/hci0
bluetoothd[1015]: plugins/policy.c:policy_adapter_probe()
bluetoothd[1015]: plugins/hostname.c:hostname_probe()
bluetoothd[1015]: profiles/audio/avrcp.c:avrcp_controller_server_probe() path /org/bluez/hci0
bluetoothd[1015]: src/adapter.c:adapter_service_add() /org/bluez/hci0
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Adding record with handle 0x10004
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000017-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000100-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001002-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 0000110e-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 0000110f-0000-1000-8000-00805f9
bluetoothd[1015]: src/adapter.c:adapter_service_insert() /org/bluez/hci0
bluetoothd[1015]: src/adapter.c:add_uuid() sending add uuid command for index 0
bluetoothd[1015]: profiles/audio/avrcp.c:avrcp_target_server_probe() path /org/bluez/hci0
bluetoothd[1015]: src/adapter.c:adapter_service_add() /org/bluez/hci0
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Adding record with handle 0x10005
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000017-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000100-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001002-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 0000110c-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 0000110e-0000-1000-8000-00805f9
bluetoothd[1015]: src/adapter.c:adapter_service_insert() /org/bluez/hci0
bluetoothd[1015]: src/adapter.c:add_uuid() sending add uuid command for index 0
bluetoothd[1015]: profiles/audio/a2dp.c:a2dp_sink_server_probe() path /org/bluez/hci0
bluetoothd[1015]: profiles/audio/a2dp.c:a2dp_source_server_probe() path /org/bluez/hci0
bluetoothd[1015]: src/adapter.c:btd_adapter_unblock_address() hci0 00:00:00:00:00:00
bluetoothd[1015]: src/adapter.c:load_link_keys() hci0 keys 0 debug_keys 0
bluetoothd[1015]: src/adapter.c:load_ltks() hci0 keys 0
bluetoothd[1015]: src/adapter.c:load_irks() hci0 irks 0
bluetoothd[1015]: src/adapter.c:load_conn_params() hci0 conn params 0
bluetoothd[1015]: src/adapter.c:load_connections() sending get connections command for index 0
bluetoothd[1015]: src/adapter.c:adapter_service_insert() /org/bluez/hci0
bluetoothd[1015]: src/adapter.c:add_uuid() sending add uuid command for index 0
bluetoothd[1015]: src/adapter.c:set_did() hci0 source 2 vendor 1d6b product 246 version 53e
bluetoothd[1015]: src/adapter.c:adapter_register() Adapter /org/bluez/hci0 registered
bluetoothd[1015]: src/adapter.c:set_dev_class() sending set device class command for index 0
bluetoothd[1015]: src/adapter.c:set_name() sending set local name command for index 0
bluetoothd[1015]: src/adapter.c:adapter_start() adapter /org/bluez/hci0 has been enabled
bluetoothd[1015]: src/adapter.c:trigger_passive_scanning()
bluetoothd[1015]: Failed to set privacy: Rejected (0x0b)
bluetoothd[1015]: src/adapter.c:load_link_keys_complete() link keys loaded for hci0
bluetoothd[1015]: src/adapter.c:load_ltks_complete() LTKs loaded for hci0
bluetoothd[1015]: src/adapter.c:load_irks_complete() IRKs loaded for hci0
bluetoothd[1015]: src/adapter.c:load_conn_params_complete() Connection Parameters loaded for hci0
bluetoothd[1015]: src/adapter.c:get_connections_complete() Connection count: 0
bluetoothd[1015]: src/profile.c:register_profile() sender :1.27
bluetoothd[1015]: src/profile.c:create_ext() Created "Message Notification"
bluetoothd[1015]: src/profile.c:ext_adapter_probe() "Message Notification" probed
bluetoothd[1015]: src/profile.c:ext_start_servers() Message Notification listening on PSM 4097
bluetoothd[1015]: src/profile.c:ext_start_servers() Message Notification listening on chan 17
bluetoothd[1015]: src/adapter.c:adapter_service_add() /org/bluez/hci0
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Adding record with handle 0x10006
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000003-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000008-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000100-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001002-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001133-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001134-0000-1000-8000-00805f9
bluetoothd[1015]: src/adapter.c:adapter_service_insert() /org/bluez/hci0
bluetoothd[1015]: src/adapter.c:add_uuid() sending add uuid command for index 0
bluetoothd[1015]: src/profile.c:register_profile() sender :1.27
bluetoothd[1015]: src/profile.c:create_ext() Created "Message Access"
bluetoothd[1015]: src/profile.c:ext_adapter_probe() "Message Access" probed
bluetoothd[1015]: src/profile.c:ext_start_servers() Message Access listening on PSM 4099
bluetoothd[1015]: src/profile.c:ext_start_servers() Message Access listening on chan 16
bluetoothd[1015]: src/adapter.c:adapter_service_add() /org/bluez/hci0
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Adding record with handle 0x10007
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000003-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000008-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000100-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001002-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001132-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001134-0000-1000-8000-00805f9
bluetoothd[1015]: src/adapter.c:adapter_service_insert() /org/bluez/hci0
bluetoothd[1015]: src/adapter.c:add_uuid() sending add uuid command for index 0
bluetoothd[1015]: src/profile.c:register_profile() sender :1.27
bluetoothd[1015]: src/profile.c:create_ext() Created "Phone Book Access"
bluetoothd[1015]: src/profile.c:ext_adapter_probe() "Phone Book Access" probed
bluetoothd[1015]: src/profile.c:ext_start_servers() Phone Book Access listening on PSM 4101
bluetoothd[1015]: src/profile.c:ext_start_servers() Phone Book Access listening on chan 15
bluetoothd[1015]: src/adapter.c:adapter_service_add() /org/bluez/hci0
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Adding record with handle 0x10008
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000003-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000008-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000100-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001002-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 0000112f-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001130-0000-1000-8000-00805f9
bluetoothd[1015]: src/adapter.c:adapter_service_insert() /org/bluez/hci0
bluetoothd[1015]: src/adapter.c:add_uuid() sending add uuid command for index 0
bluetoothd[1015]: src/profile.c:register_profile() sender :1.27
bluetoothd[1015]: src/profile.c:create_ext() Created "Synchronization"
bluetoothd[1015]: src/profile.c:ext_adapter_probe() "Synchronization" probed
bluetoothd[1015]: src/profile.c:ext_start_servers() Synchronization listening on chan 14
bluetoothd[1015]: src/adapter.c:adapter_service_add() /org/bluez/hci0
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Adding record with handle 0x10009
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000003-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000008-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000100-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001002-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001104-0000-1000-8000-00805f9
bluetoothd[1015]: src/adapter.c:adapter_service_insert() /org/bluez/hci0
bluetoothd[1015]: src/adapter.c:add_uuid() sending add uuid command for index 0
bluetoothd[1015]: src/profile.c:register_profile() sender :1.27
bluetoothd[1015]: src/profile.c:create_ext() Created "File Transfer"
bluetoothd[1015]: src/profile.c:ext_adapter_probe() "File Transfer" probed
bluetoothd[1015]: src/profile.c:ext_start_servers() File Transfer listening on PSM 4103
bluetoothd[1015]: src/profile.c:ext_start_servers() File Transfer listening on chan 10
bluetoothd[1015]: src/adapter.c:adapter_service_add() /org/bluez/hci0
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Adding record with handle 0x1000a
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000003-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000008-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000100-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001002-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001106-0000-1000-8000-00805f9
bluetoothd[1015]: src/adapter.c:adapter_service_insert() /org/bluez/hci0
bluetoothd[1015]: src/adapter.c:add_uuid() sending add uuid command for index 0
bluetoothd[1015]: src/profile.c:register_profile() sender :1.27
bluetoothd[1015]: src/profile.c:create_ext() Created "Object Push"
bluetoothd[1015]: src/profile.c:ext_adapter_probe() "Object Push" probed
bluetoothd[1015]: src/profile.c:ext_start_servers() Object Push listening on PSM 4105
bluetoothd[1015]: src/profile.c:ext_start_servers() Object Push listening on chan 9
bluetoothd[1015]: src/adapter.c:adapter_service_add() /org/bluez/hci0
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Adding record with handle 0x1000b
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000003-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000008-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000100-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001002-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001105-0000-1000-8000-00805f9
bluetoothd[1015]: src/adapter.c:adapter_service_insert() /org/bluez/hci0
bluetoothd[1015]: src/adapter.c:add_uuid() sending add uuid command for index 0
bluetoothd[1015]: profiles/audio/avdtp.c:avdtp_register_sep() SEP 0x5555692140 registered: type:0 codec:0 seid_pool:0x5555693f48 seid:1
bluetoothd[1015]: src/adapter.c:adapter_service_add() /org/bluez/hci0
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Adding record with handle 0x1000c
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000019-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000100-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001002-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 0000110a-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 0000110d-0000-1000-8000-00805f9
bluetoothd[1015]: src/adapter.c:adapter_service_insert() /org/bluez/hci0
bluetoothd[1015]: src/adapter.c:add_uuid() sending add uuid command for index 0
bluetoothd[1015]: Endpoint registered: sender=:1.31 path=/MediaEndpoint/A2DPSource
bluetoothd[1015]: profiles/audio/avdtp.c:avdtp_register_sep() SEP 0x55556a4b90 registered: type:1 codec:0 seid_pool:0x5555693f48 seid:2
bluetoothd[1015]: src/adapter.c:adapter_service_add() /org/bluez/hci0
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Adding record with handle 0x1000d
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000019-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000100-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001002-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 0000110b-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 0000110d-0000-1000-8000-00805f9
bluetoothd[1015]: src/adapter.c:adapter_service_insert() /org/bluez/hci0
bluetoothd[1015]: src/adapter.c:add_uuid() sending add uuid command for index 0
bluetoothd[1015]: Endpoint registered: sender=:1.31 path=/MediaEndpoint/A2DPSink
bluetoothd[1015]: src/profile.c:register_profile() sender :1.31
bluetoothd[1015]: src/profile.c:create_ext() Created "Headset Voice gateway"
bluetoothd[1015]: src/profile.c:ext_adapter_probe() "Headset Voice gateway" probed
bluetoothd[1015]: src/profile.c:ext_start_servers() Headset Voice gateway listening on chan 12
bluetoothd[1015]: src/adapter.c:adapter_service_add() /org/bluez/hci0
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Adding record with handle 0x1000e
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000003-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000100-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001002-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001108-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001112-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001203-0000-1000-8000-00805f9
bluetoothd[1015]: src/adapter.c:adapter_service_insert() /org/bluez/hci0
bluetoothd[1015]: src/adapter.c:add_uuid() sending add uuid command for index 0
bluetoothd[1015]: src/profile.c:register_profile() sender :1.31
bluetoothd[1015]: src/profile.c:create_ext() Created "Headset unit"
bluetoothd[1015]: src/profile.c:ext_adapter_probe() "Headset unit" probed
bluetoothd[1015]: src/profile.c:ext_start_servers() Headset unit listening on chan 3
bluetoothd[1015]: src/adapter.c:adapter_service_add() /org/bluez/hci0
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Adding record with handle 0x1000f
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000003-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00000100-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001002-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001108-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001131-0000-1000-8000-00805f9
bluetoothd[1015]: src/sdpd-service.c:add_record_to_server() Record pattern UUID 00001203-0000-1000-8000-00805f9
bluetoothd[1015]: src/adapter.c:adapter_service_insert() /org/bluez/hci0
bluetoothd[1015]: src/adapter.c:add_uuid() sending add uuid command for index 0
bluetoothd[1015]: src/adapter.c:dev_class_changed_callback() Class: 0x000000
bluetoothd[1015]: src/adapter.c:local_name_changed_callback() Name: BlueZ 5.62
bluetoothd[1015]: src/adapter.c:local_name_changed_callback() Short name:
bluetoothd[1015]: src/adapter.c:local_name_changed_callback() Current alias: BlueZ 5.62
bluetoothd[1015]: src/adapter.c:dev_class_changed_callback() Class: 0x100000
bluetoothd[1015]: src/adapter.c:dev_class_changed_callback() Class: 0x180000
bluetoothd[1015]: src/adapter.c:dev_class_changed_callback() Class: 0x1c0000
bluetoothd[1015]: src/adapter.c:dev_class_changed_callback() Class: 0x3c0000
bluetoothd[1015]: plugins/hostname.c:property_changed() static hostname: gdk8
bluetoothd[1015]: plugins/hostname.c:property_changed() pretty hostname:
bluetoothd[1015]: plugins/hostname.c:update_name() name: gdk8
bluetoothd[1015]: src/adapter.c:adapter_set_name() name: gdk8
bluetoothd[1015]: src/adapter.c:adapter_set_name() alias: gdk8
bluetoothd[1015]: src/adapter.c:set_name() sending set local name command for index 0
bluetoothd[1015]: plugins/hostname.c:property_changed() chassis:
bluetoothd[1015]: src/adapter.c:local_name_changed_callback() Name: gdk8
bluetoothd[1015]: src/adapter.c:local_name_changed_callback() Short name:
bluetoothd[1015]: src/adapter.c:local_name_changed_callback() Current alias: gdk8
bluetoothd[1015]: src/adapter.c:start_discovery() sender :1.43
bluetoothd[1015]: src/adapter.c:update_discovery_filter()
bluetoothd[1015]: src/adapter.c:discovery_filter_to_mgmt_cp()
bluetoothd[1015]: src/adapter.c:trigger_start_discovery()
bluetoothd[1015]: src/adapter.c:cancel_passive_scanning()
bluetoothd[1015]: src/adapter.c:start_discovery_timeout()
bluetoothd[1015]: src/adapter.c:start_discovery_timeout() adapter->current_discovery_filter == 0
bluetoothd[1015]: src/adapter.c:start_discovery_complete() status 0x00
没有-d选项：
(gdb) r
Starting program: /usr/lib/bluetooth/bluetoothd -n
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/aarch64-linux-gnu/libthread_db.so.1".
bluetoothd[1056]: Bluetooth daemon 5.62
bluetoothd[1056]: Starting SDP server
bluetoothd[1056]: profiles/network/bnep.c:bnep_init() kernel lacks bnep-protocol support
bluetoothd[1056]: src/plugin.c:plugin_init() System does not support network plugin
bluetoothd[1056]: Bluetooth management interface 1.10 initialized
bluetoothd[1056]: src/adapter.c:reset_adv_monitors_complete() Failed to reset Adv Monitors: Unknown Command (0x01)
bluetoothd[1056]: Failed to set privacy: Rejected (0x0b)
bluetoothd[1056]: Endpoint registered: sender=:1.31 path=/MediaEndpoint/A2DPSource
bluetoothd[1056]: Endpoint registered: sender=:1.31 path=/MediaEndpoint/A2DPSink在discovering_callback函数处设置一个断点，然后跑起来；如下所示。
Breakpoint 1, discovering_callback (index=0, length=2, param=0x555568cf66, user_data=0x5555693aa0)
at src/adapter.c:1932
1932 {
(gdb) info b
Num Type Disp Enb Address What
1 breakpoint keep y 0x00000055555d28d8 in discovering_callback at src/adapter.c:1932
breakpoint already hit 1 time
(gdb)输入disassemble看一下，可以看到_btddebug_desc，想必是discovering_callback内使用了DBG(……)。
(gdb) disassemble
Dump of assembler code for function discovering_callback:
=> 0x00000055555d28d8 <+0>: and w1, w1, #0xffff
0x00000055555d28dc <+4>: cmp w1, #0x1
0x00000055555d28e0 <+8>: b.ls 0x55555d29bc <discovering_callback+228> // b.plast
0x00000055555d28e4 <+12>: stp x29, x30, [sp, #-32]!
0x00000055555d28e8 <+16>: adrp x0, 0x555567d000 <__btd_debug_desc.19910>
0x00000055555d28ec <+20>: mov x29, sp
0x00000055555d28f0 <+24>: ldr w0, [x0, #1768]
0x00000055555d28f4 <+28>: stp x19, x20, [sp, #16]
0x00000055555d28f8 <+32>: mov x19, x3
0x00000055555d28fc <+36>: mov x20, x2
0x00000055555d2900 <+40>: ldrb w6, [x2, #1]
0x00000055555d2904 <+44>: tbnz w0, #0, 0x55555d2950 <discovering_callback+120>
0x00000055555d2908 <+48>: ldrb w0, [x19, #132]
0x00000055555d290c <+52>: cmp w0, w6
0x00000055555d2910 <+56>: b.eq 0x55555d2944 <discovering_callback+108> // b.none
0x00000055555d2914 <+60>: ldr x0, [x19, #136]
0x00000055555d2918 <+64>: ldrb w1, [x20]
0x00000055555d291c <+68>: strb w1, [x19, #131]
0x00000055555d2920 <+72>: strb w6, [x19, #132]
0x00000055555d2924 <+76>: cbz x0, 0x55555d2988 <discovering_callback+176>
0x00000055555d2928 <+80>: ldrb w0, [x19, #133]
0x00000055555d292c <+84>: cbnz w0, 0x55555d2944 <discovering_callback+108>
0x00000055555d2930 <+88>: cbz w6, 0x55555d29a0 <discovering_callback+200>
0x00000055555d2934 <+92>: cmp w6, #0x1
0x00000055555d2938 <+96>: b.ne 0x55555d2944 <discovering_callback+108> // b.any
0x00000055555d293c <+100>: ldr w0, [x19, #176]
0x00000055555d2940 <+104>: cbnz w0, 0x55555d29e0 <discovering_callback+264>
0x00000055555d2944 <+108>: ldp x19, x20, [sp, #16]
0x00000055555d2948 <+112>: ldp x29, x30, [sp], #32
0x00000055555d294c <+116>: ret
0x00000055555d2950 <+120>: ldrb w7, [x3, #129]
0x00000055555d2954 <+124>: adrp x1, 0x555563d000
0x00000055555d2958 <+128>: ldrb w5, [x2]
0x00000055555d295c <+132>: add x1, x1, #0xeb0
0x00000055555d2960 <+136>: ldrh w4, [x3, #4]
0x00000055555d2964 <+140>: adrp x3, 0x555563b000 <__func__.15864>
0x00000055555d2968 <+144>: add x3, x3, #0xc28
0x00000055555d296c <+148>: adrp x2, 0x555563c000 <__func__.25491>
0x00000055555d2970 <+152>: add x3, x3, #0x438
0x00000055555d2974 <+156>: add x2, x2, #0x920
---Type <return> to continue, or q <return> to quit---qx /2gx 0x555567d000 继续看一下里面的信息；第一个参数就是文件名，利用p (char*)把结果显示成人类可见的形式后，就可以看到”src/gatt-database.c”文件名了；第二个参数就是标志位的信息了，此时标志位为1，这就代表会打印调试信息；当然也可以利用set去手动修改标志位。
(gdb) x /2gx 0x555567d000
0x555567d000 <__btd_debug_desc.19910>: 0x00000055556384a8 0x0000000000000001
(gdb) p (char*)0x00000055556384a8
$2 = 0x55556384a8 "src/gatt-database.c"
(gdb) set *(int*)(0x555567d000+8)=0
(gdb) x /2gx 0x555567d000
0x555567d000 <__btd_debug_desc.19910>: 0x00000055556384a8 0x0000000000000000
(gdb)假如已经选上了-d选项，那么标志位是不支持修改的，固定是1。
(gdb) x /2gx 0x555567d000
0x555567d000 <__btd_debug_desc.19910>: 0x00000055556384a8 0x0000000000000001
(gdb) p (char*)0x00000055556384a8
$2 = 0x55556384a8 "src/gatt-database.c"
(gdb) set *(int*)(0x555567d000+8)=0
(gdb) x /2gx 0x555567d000
0x555567d000 <__btd_debug_desc.19910>: 0x00000055556384a8 0x0000000000000001
(gdb)除此之外，还可以手动调用一下_btdtoggle_debug 函数，切换到调试模式，好多打印一些信息，以帮助我们去排查问题。
(gdb) call __btd_toggle_debug()
(gdb) c
Continuing.
bluetoothd[1094]: src/adapter.c:discovering_callback() hci0 type 7 discovering 0 method 0
bluetoothd[1094]: src/adapter.c:trigger_start_discovery()
bluetoothd[1094]: src/adapter.c:cancel_passive_scanning()
bluetoothd[1094]: src/adapter.c:stop_discovery() sender :1.52
bluetoothd[1094]: src/adapter.c:discovery_remove() owner :1.52
bluetoothd[1094]: src/adapter.c:discovery_free() 0x55556a76d0
bluetoothd[1094]: src/adapter.c:trigger_passive_scanning()
bluetoothd[1094]: src/adapter.c:start_discovery() sender :1.52
bluetoothd[1094]: src/adapter.c:update_discovery_filter()
bluetoothd[1094]: src/adapter.c:discovery_filter_to_mgmt_cp()
bluetoothd[1094]: src/adapter.c:trigger_start_discovery()
bluetoothd[1094]: src/adapter.c:cancel_passive_scanning()
bluetoothd[1094]: src/adapter.c:start_discovery_timeout()
bluetoothd[1094]: src/adapter.c:start_discovery_timeout() adapter->current_discovery_filter == 0
bluetoothd[1094]: src/adapter.c:start_discovery_complete() status 0x00
Breakpoint 1, discovering_callback (index=0, length=2, param=0x555568cf66, user_data=0x5555693aa0)
at src/adapter.c:1932
1932 {
(gdb) c
Continuing.
bluetoothd[1094]: src/adapter.c:discovering_callback() hci0 type 7 discovering 1 method 0
Breakpoint 1, discovering_callback (index=0, length=2, param=0x555568cf66, user_data=0x5555693aa0)
at src/adapter.c:1932
1932 {先用了一下GDB，不还是使用Nano Code调试起来更爽一点；光是图形化的界面就要胜出不少，而且不管看寄存器信息、反汇编信息还是源代码，这都要比GDB方便上不少。
打印日志
蓝牙默认是不把日志打印出来的，但是假如想要获取更多关于蓝牙的信息，那么我们还是要想办法把日志打印出来；
在src/shared/log.c内加上如下的代码，输出日志到/var/log内。
先判断一下当前进程有没有日志，避免重复；之前没有日志的话，就把日志输出到/var/log下面；最后判断一下当前进程有没有日志，有日志的话，就把信息放到日志里面。
#include <time.h>
int GetLogFileName(char* szFullFileName, int dwSize)
{
time_t timep;
struct tm *ptm;
time(&timep);
ptm = localtime(&timep);
pid_t pid;
pid = getpid();
sprintf(szFullFileName, "/var/log/bluez%d%02d%02d_%02d%02d%02d_%d.log",
ptm->tm_year+1900, ptm->tm_mon+1, ptm->tm_mday,
ptm->tm_hour, ptm->tm_min, ptm->tm_sec,
pid);
return 0;
}
在int bt_log_open()内，return err;的下方添加：
if (log_file == NULL){
GetLogFileName(szFileName, sizeof(szFileName));
log_file = fopen(szFileName, "wb+");
}
在int bt_log_vprintf()内，len = strlen(str);的下方添加：
if(log_file != NULL){
str[len] = '\n';
fwrite(str, 1, len + 1, log_file);
fflush(log_file);
}此时再次启动蓝牙，就可以看到打印的日志了；如下图所示。
蓝牙进程杀掉后还会自动启动，需要中止服务才可以 [sudo systemctl disable bluetooth]，想要恢复自动启动的状态再enable即可。
如何让内核”日记“一条不丢？
当我们想要查看内核相关信息的时候，经常会用到dmesg命令，但是我们知道dmesg是从环形缓冲区内得到这些消息的，而这个缓冲区通常只有128KB的大小；假如内核打印的消息过多，就难免会“丢掉”前面的消息，那么如何保证让内核信息一条也不丢失呢？
可以参考文章：https://www.nanocode.cn/wiki/docs/gdk8_primer/primer_gdk8_buflen
结果
蓝牙无法搜索到设备是固件的问题，到官网的软件更新上下载新版本的镜像之后，即可解决问题。
作者：admin 创建时间：2021-12-03 17:45
最后编辑：Taylor 更新时间：2024-03-12 10:45
最后编辑：Taylor 更新时间：2024-03-12 10:45
