Ref.
http://stackoverflow.com/questions/8166415/how-to-get-the-pid-of-a-process-in-linux-in-c
http://stackoverflow.com/questions/15692275/how-to-kill-a-process-tree-programmatically-on-linux-using-c
http://fanqiang.chinaunix.net/a4/b8/20010811/0905001105_b.html
http://stackoverflow.com/questions/8166415/how-to-get-the-pid-of-a-process-in-linux-in-c
http://stackoverflow.com/questions/15692275/how-to-kill-a-process-tree-programmatically-on-linux-using-c
http://fanqiang.chinaunix.net/a4/b8/20010811/0905001105_b.html
