Merge pull request #128 from ffac/update-location-gps

ffac-update-location-gps: initial package version

ffac-update-location-gps/Makefile

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+# SPDX-FileCopyrightText: 2024 Florian Maurer, xelo
+# SPDX-License-Identifier: MIT
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=ffac-update-location-gps
+PKG_VERSION:=1.0
+PKG_RELEASE:=1
+
+PKG_LICENSE:=MIT
+
+include $(TOPDIR)/../package/gluon.mk
+
+define Package/$(PKG_NAME)
+  TITLE:=Use attached GPS controller to update location from it
+  DEPENDS:=+kmod-usb-core +kmod-usb-ohci +kmod-usb2 +kmod-usb-acm +kmod-usb-serial-pl2303 +micrond
+endef
+
+define Package/$(PKG_NAME)/description
+  If enabled, this package updates the gluon-node-info location based on the NMEA output of an attached GPS device.
+endef
+
+$(eval $(call BuildPackageGluon,$(PKG_NAME)))

ffac-update-location-gps/README.md

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+# ffac-update-location-gps
+
+This package configures gluon to update the location based on tty output of an attached GPS device.
+
+When a USB device which provides a tty is attached, it updates the location based on the output of it.
+This is done using a lua rewrite of the script from the original forum posting.
+It seems to work without coreutils-stty installed, which did fail the installation when selected as package dependency.
+
+The location is only updated in memory - and only if a valid GPS fix is available.
+After a reboot, the old location from the config is set.
+
+## behvario and lockfiles
+
+This creates a lockfile `/var/lock/hotplug-update-location-gps_$DEVNAME.lock` per found TTY device and sets up a cron job which runs every 5 minutes to check if coordinates are available from the stream.
+If the TTY is not in use, the open stream waits for the first line to be read (never) and is stuck.
+A lockfile `/var/lock/update-location-gps_$TTYDEVICE` is used to check if the cron is already running/stuck and does not start another reading terminal in that case.
+
+On creation and removal of the micron.d job, the micron.d service is restarted
+
+
+## further information
+
+Further information can be found here:
+
+* https://github.com/dmth/gluon-gps-locationupdate
+* https://forum.freifunk.net/t/freifunk-location-update-via-gps/1493

ffac-update-location-gps/files/etc/config/update-location-gps

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+config settings 'settings'
+	option enabled '0'

ffac-update-location-gps/files/etc/hotplug.d/tty/10-update-location-gps

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+#!/bin/sh
+lockpath="/var/lock/hotplug-update-location-gps_${DEVNAME}.lock"
+
+if [ "${ACTION}" = "add" ]; then
+	enabled=$(uci get update-location-gps.settings.enabled)
+	[ "${enabled}" != "1" ] && exit 0
+	test -e "${lockpath}" && exit 0
+	echo "hotplug-update-location-gps: TTY device ${DEVNAME} was plugged in" > /dev/kmsg
+	echo "${DEVPATH}" > "${lockpath}"
+	echo "*/5 * * * *  /usr/bin/update-location-gps /dev/${DEVNAME} | logger -t update-location-gps" > "/usr/lib/micron.d/update-location-gps_${DEVNAME}"
+	/etc/init.d/micrond restart
+fi
+
+if [ "${ACTION}" = "remove" ]; then
+	if [ "${DEVPATH}" = "$(cat "${lockpath}")" ]; then
+		echo "hotplug-update-location-gps: TTY device ${DEVNAME} was removed" > /dev/kmsg
+		rm -f "/usr/lib/micron.d/update-location-gps_${DEVNAME}"
+		/etc/init.d/micrond restart
+		rm "${lockpath}"
+	fi
+fi

ffac-update-location-gps/luasrc/usr/bin/update-location-gps

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+#!/usr/bin/lua
+
+if not arg[1] then
+    print("Error: No /dev/tty* path specified. Please provide a TTY device path as the first argument.")
+    os.exit(1)
+end
+
+local uci = require('simple-uci').cursor()
+local bit = require 'bit'
+local fcntl = require 'posix.fcntl'
+local unistd = require 'posix.unistd'
+
+-- Get GPS device tty
+local tty_device = arg[1]
+
+-- Use GPS as Stream
+local file = io.open(tty_device, "r")
+if not file then
+    print("Error: Unable to open " .. tty_device)
+    os.exit(2)
+end
+
+local lockfilename = "/var/lock/update-location-gps_" .. string.gsub(tty_device, "/", "_")
+
+local lockfd, err = fcntl.open(lockfilename, bit.bor(fcntl.O_WRONLY, fcntl.O_CREAT), 384) -- mode 0600
+if not lockfd then
+  print('err', err)
+  local err_verbose = string.format("Unable to get file descriptor for lock file %s .", lockfilename)
+  print('err', err_verbose)
+  os.exit(1)
+end
+
+local ok, _ = fcntl.fcntl(lockfd, fcntl.F_SETLK, {
+  l_start = 0,
+  l_len = 0,
+  l_type = fcntl.F_WRLCK,
+  l_whence = unistd.SEEK_SET,
+})
+if not ok then
+  -- silent as this is run in cron
+  os.exit(1)
+end
+
+local line_count = 0
+local max_lines = 50
+
+while line_count < max_lines do
+    local this_line = file:read("*line")
+    if not this_line then break end  -- Exit loop if no more lines
+
+    line_count = line_count + 1  -- Increment the line counter
+
+    local nc = this_line:match("^([^,]+)")
+
+    if nc == '$GPRMC' then
+        local fields = {}
+        for field in this_line:gmatch("([^,]+)") do
+            table.insert(fields, field)
+        end
+
+        local valid = fields[3]
+
+        if valid == "A" then
+            -- First: Retrieve coordinate
+            local lat = fields[4]
+            local lon = fields[6]
+
+            -- Second: Determine if coordinate is oriented North/South or East/West
+            local latdir = fields[5]
+            local londir = fields[7]
+
+            -- Split DEGREES from coordinate
+            local latdeg = tonumber(lat:sub(1, 2))
+            local londeg = tonumber(lon:sub(1, 3))
+
+            -- Split MINUTES.SECONDS from coordinate
+            local latmin = tonumber(lat:sub(3))
+            local lonmin = tonumber(lon:sub(4))
+
+            -- Convert from Degree-Minutes to Decimal-Minutes
+            local latdec = latmin / 60
+            local londec = lonmin / 60
+
+            -- Use negative notation instead of North/South or East/West
+            if latdir == 'S' then
+                latdeg = -latdeg
+            end
+            if londir == 'W' then
+                londeg = -londeg
+            end
+            lat = string.format("%f", latdeg + latdec)
+            lon = string.format("%f", londeg + londec)
+
+            print("GPS position is valid Lat/Lon:", lat, lon)
+            -- set temp location in gluon-node-info
+            uci:set('gluon-node-info', '@location[0]', 'latitude', lat)
+            uci:set('gluon-node-info', '@location[0]', 'longitude', lon)
+            uci:save('gluon-node-info')
+            -- Link to Phip's comment: https://forum.freifunk.net/t/freifunk-location-update-via-gps/1493/2
+            -- Committing here would wear out the nvram very fast, so it should not be done.
+            break
+        else
+            print("GPS position is Invalid...", valid)
+            break
+        end
+    end
+end
+
+file:close()
+os.exit(0)