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Many users are reluctant to use libgpiod instead of the deprecated /sys/class/gpio interface. The gpiod-sysfs-proxy project aims at making the transition easier by implementing a compatibility layer in user-space using FUSE and python3-gpiod. This way we can eat the cookie by disabling the sysfs ABI and have the users have it too by sticking to their existing scripts. The project itself is a very simple setuptools-based python package but the recipe is quite complex due to comprehensive distro integration. By default we use /run/gpio as mountpoint. For full backward compatibility with the kernel interface, the user must explicitly add the 'sys-class-mount' switch to PACKAGECONFIG. We do this because, depending on whether CONFIG_GPIO_SYSFS Kconfig option is enabled, /sys/class/gpio will either be non-empty or not exist at all. In the latter case, we need to somehow create the /sys/class/gpio and, since user-space is not allowed to mkdir() inside sysfs, we use overlayfs for that. As this is rather non-standard, we want the user to be aware of this. We support both systemd and sys V init managers. We also provide a ptest package which uses an external gpio-sysfs-compat-tests script. Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> Signed-off-by: Khem Raj <raj.khem@gmail.com>
85 lines
1.7 KiB
Bash
85 lines
1.7 KiB
Bash
#! /bin/sh
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### BEGIN INIT INFO
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# Provides: gpiod-sysfs-proxy
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# Required-Start: $remote_fs $syslog
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# Required-Stop: $remote_fs $syslog
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# Default-Start: 2 3 4 5
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# Default-Stop: 1
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# Short-Description: User-space, libgpiod-based compatibility layer for linux GPIO sysfs interface.
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### END INIT INFO
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#
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# -*- coding: utf-8 -*-
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# Debian init.d script for gpiod-sysfs-proxy
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# Copyright (c) 2024 Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
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# set -e
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# Source function library.
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. /etc/init.d/functions
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PROG="/usr/bin/gpiod-sysfs-proxy"
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NAME="gpiod-sysfs-proxy"
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DESC="/sys/class/gpio compatibility layer"
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MOUNTPOINT="@mountpoint@"
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test -x $PROG || exit 0
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do_start()
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{
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echo -n "Starting $DESC: "
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if [ "$MOUNTPOINT" = "/sys/class/gpio" ] && [ ! -e /sys/class/gpio ]; then
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mkdir -p /run/gpio/sys /run/gpio/class/gpio /run/gpio/work
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mount -t sysfs sysfs /run/gpio/sys -o nosuid,nodev,noexec
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# Bail out if overlayfs is not available
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set -e
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mount -t overlay overlay /sys/class \
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-o upperdir=/run/gpio/class,lowerdir=/run/gpio/sys/class,workdir=/run/gpio/work,nosuid,nodev,noexec,relatime,ro
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set +e
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else
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mkdir -p $MOUNTPOINT
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fi
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$PROG $MOUNTPOINT -o nonempty -o allow_other -o default_permissions -o entry_timeout=0 -f | logger -i $NAME &
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echo "done"
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}
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do_stop()
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{
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echo -n "Stopping $DESC: "
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umount $MOUNTPOINT
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mountpoint -q /sys/class
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if [ "$?" = "0" ]; then
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umount /sys/class
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umount /run/gpio/sys
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rm -rf /run/gpio
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fi
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echo "done"
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}
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case "$1" in
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start)
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do_start
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;;
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stop)
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do_stop
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;;
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status)
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status $PROG
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exit $?
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;;
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restart)
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do_stop
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sleep 1
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do_start
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;;
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*)
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echo "Usage: /etc/init.d/$NAME {start|stop|status|restart}" >&2
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exit 1
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;;
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esac
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exit 0
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