无法在嵌入式 linux 中使用 bluetoothctl 连接设备

Posted 2023-04-14

【中文标题】无法在嵌入式 linux 中使用 bluetoothctl 连接设备

【英文标题】：Can not connect a device with bluetoothctl in an embedded linux

【发布时间】：2021-07-26 14:20:16

【问题描述】：

我为嵌入式 linux 交叉编译了 Bluez 和 d-bus 库，然后我运行了 dbus-daemon 和 bluetoothd。但我无法在 bluetoothctl 上连接设备。扫描适用于 bluetoothctl，甚至连接适用于 hcitool。无法仅在 bluetoothctl 上连接，并出现此错误：（连接失败：org.bluez.error.failed）

我怀疑 d-bus 守护程序配置存在问题，但我不确定。 以下是我的 d-bus 配置。

系统配置文件

<!-- This configuration file controls the systemwide message bus.
     Add a system-local.conf and edit that rather than changing this 
     file directly. -->

<!-- Note that there are any number of ways you can hose yourself
     security-wise by screwing up this file; in particular, you
     probably don't want to listen on any more addresses, add any more
     auth mechanisms, run as a different user, etc. -->

<!DOCTYPE busconfig PUBLIC "-//freedesktop//DTD D-Bus Bus Configuration 1.0//EN"
 "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
<busconfig>

  <!-- Our well-known bus type, do not change this -->
  <type>system</type>

  <!-- Run as special user -->
  <user>messagebus</user>

  <!-- Fork into daemon mode -->
  <fork/>

  <!-- We use system service launching using a helper -->
  <standard_system_servicedirs/>

  <!-- This is a setuid helper that is used to launch system services -->
  <servicehelper>/customer/daemon/dbus-daemon-launch-helper</servicehelper>

  <!-- Write a pid file -->
  <pidfile>/customer/daemon/var/run/dbus/pid</pidfile>

  <!-- Enable logging to syslog -->
  <syslog/>

  <!-- Only allow socket-credentials-based authentication -->
  <auth>EXTERNAL</auth>

  <!-- Only listen on a local socket. (abstract=/path/to/socket 
       means use abstract namespace, don't really create filesystem 
       file; only Linux supports this. Use path=/whatever on other 
       systems.) -->
  <listen>unix:path=/customer/daemon/var/run/dbus/system_bus_socket</listen>

  <policy context="default">
    <!-- All users can connect to system bus -->
    <allow user="*"/>

    <!-- Holes must be punched in service configuration files for
         name ownership and sending method calls -->
    <deny own="*"/>
    <deny send_type="method_call"/>

    <!-- Signals and reply messages (method returns, errors) are allowed
         by default -->
    <allow send_type="signal"/>
    <allow send_requested_reply="true" send_type="method_return"/>
    <allow send_requested_reply="true" send_type="error"/>

    <!-- All messages may be received by default -->
    <allow receive_type="method_call"/>
    <allow receive_type="method_return"/>
    <allow receive_type="error"/>
    <allow receive_type="signal"/>

    <!-- Allow anyone to talk to the message bus -->
    <allow send_destination="org.freedesktop.DBus"
           send_interface="org.freedesktop.DBus" />
    <allow send_destination="org.freedesktop.DBus"
           send_interface="org.freedesktop.DBus.Introspectable"/>
    <allow send_destination="org.freedesktop.DBus"
           send_interface="org.freedesktop.DBus.Properties"/>
    <!-- But disallow some specific bus services -->
    <deny send_destination="org.freedesktop.DBus"
          send_interface="org.freedesktop.DBus"
          send_member="UpdateActivationEnvironment"/>
    <deny send_destination="org.freedesktop.DBus"
          send_interface="org.freedesktop.DBus.Debug.Stats"/>
    <deny send_destination="org.freedesktop.DBus"
          send_interface="org.freedesktop.systemd1.Activator"/>
  </policy>

  <!-- Only systemd, which runs as root, may report activation failures. -->
  <policy user="root">
    <allow send_destination="org.freedesktop.DBus"
           send_interface="org.freedesktop.systemd1.Activator"/>
  </policy>

  <!-- root may monitor the system bus. -->
  <policy user="root">
    <allow send_destination="org.freedesktop.DBus"
           send_interface="org.freedesktop.DBus.Monitoring"/>
  </policy>

  <!-- If the Stats interface was enabled at compile-time, root may use it.
       Copy this into system.local.conf or system.d/*.conf if you want to
       enable other privileged users to view statistics and debug info -->
  <policy user="root">
    <allow send_destination="org.freedesktop.DBus"
           send_interface="org.freedesktop.DBus.Debug.Stats"/>
  </policy>

  <!-- Include legacy configuration that was preserved in a Debian upgrade,
       if any -->
  <include ignore_missing="yes">/etc/dbus-1/system.conf.dpkg-bak</include>

  <!-- The defaults for these limits are hard-coded in dbus-daemon.
       Some clarifications:
       Times are in milliseconds (ms); 1000ms = 1 second
       133169152 bytes = 127 MiB
       33554432 bytes = 32 MiB
       150000ms = 2.5 minutes -->
  <!-- <limit name="max_incoming_bytes">133169152</limit> -->
  <!-- <limit name="max_incoming_unix_fds">64</limit> -->
  <!-- <limit name="max_outgoing_bytes">133169152</limit> -->
  <!-- <limit name="max_outgoing_unix_fds">64</limit> -->
  <!-- <limit name="max_message_size">33554432</limit> -->
  <!-- <limit name="max_message_unix_fds">16</limit> -->
  <!-- <limit name="service_start_timeout">25000</limit> -->
  <!-- <limit name="auth_timeout">5000</limit> -->
  <!-- <limit name="pending_fd_timeout">150000</limit> -->
  <!-- <limit name="max_completed_connections">2048</limit> -->
  <!-- <limit name="max_incomplete_connections">64</limit> -->
  <!-- <limit name="max_connections_per_user">256</limit> -->
  <!-- <limit name="max_pending_service_starts">512</limit> -->
  <!-- <limit name="max_names_per_connection">512</limit> -->
  <!-- <limit name="max_match_rules_per_connection">512</limit> -->
  <!-- <limit name="max_replies_per_connection">128</limit> -->

  <!-- Config files are placed here that among other things, punch 
       holes in the above policy for specific services. -->
  <includedir>system.d</includedir>

  <includedir>/customer/daemon/etc/dbus-1/system.d</includedir>

  <!-- This is included last so local configuration can override what's 
       in this standard file -->
  <include ignore_missing="yes">/customer/daemon/etc/dbus-1/system-local.conf</include>

  <include if_selinux_enabled="yes" selinux_root_relative="yes">contexts/dbus_contexts</include>

</busconfig>

蓝牙配置文件

<!-- This configuration file specifies the required security policies
     for Bluetooth core daemon to work. -->

<!DOCTYPE busconfig PUBLIC "-//freedesktop//DTD D-BUS Bus Configuration 1.0//EN"
 "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
<busconfig>

  <!-- ../system.conf have denied everything, so we just punch some holes -->

  <policy user="root">
    <allow own="org.bluez"/>
    <allow send_destination="org.bluez"/>
    <allow send_interface="org.bluez.Agent1"/>
    <allow send_interface="org.bluez.MediaEndpoint1"/>
    <allow send_interface="org.bluez.MediaPlayer1"/>
    <allow send_interface="org.bluez.Profile1"/>
    <allow send_interface="org.bluez.GattCharacteristic1"/>
    <allow send_interface="org.bluez.GattDescriptor1"/>
    <allow send_interface="org.bluez.LEAdvertisement1"/>
    <allow send_interface="org.freedesktop.DBus.ObjectManager"/>
    <allow send_interface="org.freedesktop.DBus.Properties"/>
  </policy>

  <!-- allow users of bluetooth group to communicate -->
  <policy group="bluetooth">
    <allow send_destination="org.bluez"/>
  </policy>

  <policy at_console="true">
    <allow send_destination="org.bluez"/>
  </policy>

  <!-- allow users of lp group (printing subsystem) to 
       communicate with bluetoothd -->
  <policy group="lp">
    <allow send_destination="org.bluez"/>
  </policy>

  <policy context="default">
    <deny send_destination="org.bluez"/>
  </policy>

</busconfig>

【参考方案1】：

不确定是什么问题，但您可以启用 bluetoodhd 调试日志并粘贴到此处，以便于理解问题。 在文件 /etc/systemd/system/bluetooth.target.wants/bluetooth.service 或 /lib/systemd/system/bluetooth.service

通过在运行 bluetoothd 时添加 -d 选项来启用调试，如下所示 ExecStart=/usr/libexec/bluetooth/bluetoothd -d 然后可以看到日志 /var/log/syslog | grep 蓝牙