首先需要启动守护进程
dbus-daemon –system –print-pid –print-address
结果提示 Failed to start message bus: Could not get UID and GID for
username "messagebus"
dbus需要有一个messagebus用户，创建该用户即可，useradd
messagebus，问题解决。

执行一个dbus测试程序，提示：D-Bus library appears to be incorrectly set
up; failed to read machine uuid: Failed to open
"/usr/var/lib/dbus/machine-id": No such file or directory
没有machine-id文件，查了一下，需要给它定义一个id，使用dbus-uuidgen
>/usr/var/lib/dbus/machine-id
产生这个文件，该问题解决。

再次执行测试程序，又有问题：Couldn't connect to session bus: Failed to
execute dbus-launch to autolaunch D-Bus
session,看了帮助http://dbus.freedesktop.org/doc/dbus-launch.1.html
AUTOMATIC
LAUNCHING一节，需要设置DBUS_SESSION_BUS_ADDRESS环境变量的值，先执行dbus-launch,获得了DBUS_SESSION_BUS_ADDRESS值，再export一下，最后执行测试程序，OK了

在dbus帮助中有一篇关于dbus-launch的文章，可以在脚本中启动dbus-launch，同时自动设置DBUS_SESSION_BUS_ADDRESS环境变量，脚本文件rundbus如下：

if test -z "$DBUS_SESSION_BUS_ADDRESS" ; then
## if not found, launch a new one
`dbus-launch --sh-syntax --exit-with-session`
echo "D-Bus per-session daemon address is: $DBUS_SESSION_BUS_ADDRESS"
fi

执行. rundbus即可。