讓普通用戶可以控制樹莓派的GPIO(Archlinuxarm)

Raspbian上的Rpi.GPIO庫是可以在普通用戶下控制樹莓派的GPIO的，然而在ArchlinuxARM下，卻需要root用戶才行，這無疑會引起安全問題，好在RPi.GPIO提供了一個獲取權限的腳本：create_gpio_user_permissions.py

然而這個腳本是沒法在ArchlinuxARM上直接運行的，因為Archlinux缺少adduser命令。

這個腳本是這樣的：

import grp
import subprocess

def ensure_gpiogroup():
    try:
        grp.getgrnam('gpio')
    except KeyError:
        print('GPIO group does not exist - creating...')
        subprocess.call(['groupadd', '-f', '-r', 'gpio'])
        subprocess.call(['adduser', 'pi', 'gpio'])
        # in future, also for groups:
        #   spi
        #   i2c
        add_udev_rules()

def add_udev_rules():
    with open('/etc/udev/rules.d/99-gpio.rules','w') as f:
        f.write("""SUBSYSTEM=="bcm2835-gpiomem", KERNEL=="gpiomem", GROUP="gpio", MODE="0660"
SUBSYSTEM=="gpio", KERNEL=="gpiochip*", ACTION=="add", PROGRAM="/bin/sh -c 'chown root:gpio /sys/class/gpio/export /sys/class/gpio/unexport ; chmod 220 /sys/class/gpio/export /sys/class/gpio/unexport'"
SUBSYSTEM=="gpio", KERNEL=="gpio*", ACTION=="add", PROGRAM="/bin/sh -c 'chown root:gpio /sys%p/active_low /sys%p/direction /sys%p/edge /sys%p/value ; chmod 660 /sys%p/active_low /sys%p/direction /sys%p/edge /sys%p/value'"
""")

if __name__ == '__main__':
    ensure_gpiogroup()

反正很簡單，手動搞進去就行了

首先，建一個gpio組：

groupadd -f -r gpio

然后把當前用戶（我的用戶是yafeng）加入到gpio組

 gpasswd -a yafeng gpio

然后建立udev的規則文件：/etc/udev/rules.d/99-gpio.rules

SUBSYSTEM=="bcm2835-gpiomem", KERNEL=="gpiomem", GROUP="gpio", MODE="0660"
SUBSYSTEM=="gpio", KERNEL=="gpiochip*", ACTION=="add", PROGRAM="/bin/sh -c 'chown root:gpio /sys/class/gpio/export /sys/class/gpio/unexport ; chmod 220 /sys/class/gpio/export /sys/class/gpio/unexport'"
SUBSYSTEM=="gpio", KERNEL=="gpio*", ACTION=="add", PROGRAM="/bin/sh -c 'chown root:gpio /sys%p/active_low /sys%p/direction /sys%p/edge /sys%p/value ; chmod 660 /sys%p/active_low /sys%p/direction /sys%p/edge /sys%p/value'"

然后重啟，就可以直接在普通用戶下操作GPIO了，經測試，不光Rpi.GPIO庫,wiringpi等其他庫也可以了