linux 程序 打开 /dev/mem permission denied

链接：
http://www.element14.com/community/thread/19995/l/anyone-know-how-to-access-raspi-gpio-without-sudo?displayFullThread=true

Unix has a “security model”. As a normal users you can do stuff, but
you should not be able to access other people’s files on the same
computer. And as a user you should not be able to cause the computer
to stop working.

The program can be made setuid by doing

  sudo chown root 
  sudo chmod 4755 

或者 使用 +setuid , see link: http://blog.csdn.net/gw569453350game/article/details/51499828