gluon-core: add ath79 migration

Add a universal migration script suited for migrating devices from the
removed ar71xx target to ath79.

While at it, try to abstract as much functionality possibly required in
the future for other migrations and implement it in the newly created
gluon.migration Lua package.

Signed-off-by: David Bauer <mail@david-bauer.net>

package/gluon-core/files/lib/gluon/core/migration/create_led_config.sh

@@ -0,0 +1,15 @@
+#!/bin/sh
+
+CFG=/etc/board.json
+
+. /lib/functions/config-generate.sh
+
+json_init
+json_load "$(cat ${CFG})"
+
+umask 077
+
+keys=
+
+json_get_keys keys led
+for key in $keys; do generate_led $key; done

package/gluon-core/files/lib/upgrade/keep.d/gluon

@@ -1 +1,2 @@
 /lib/gluon/core/sysconfig/
+/lib/gluon/core/migration/flags

package/gluon-core/luasrc/lib/gluon/upgrade/002-ath79-migration

@@ -0,0 +1,98 @@
+#!/usr/bin/lua
+
+local platform = require 'gluon.platform'
+local sysconfig = require 'gluon.sysconfig'
+local migration = require 'gluon.migration'
+
+local uci = require('simple-uci').cursor()
+
+local migration_name = 'ar71xx-ath79'
+
+local migration_target_config = {
+	-- {DEVICE, ETH_SWAP}
+}
+
+-- Create a list for use with platform matching
+local migration_targets = {}
+for _, v in ipairs(migration_target_config) do
+	table.insert(migration_targets, v[0])
+end
+
+-- Check if device is a migration target
+if not platform.match('ath79', 'generic', migration_targets) then
+    return
+end
+
+-- Check if this is an initial installation
+if not sysconfig.gluon_version then
+    os.execute('touch /lib/gluon/core/migrations/ar71xx-ath79')
+    return
+end
+
+-- Check if migration has already been done
+if migration.is_migration_done(migration_name) then
+    return
+end
+
+-- Reinit board.json
+migration.reinit_board_json()
+
+migration.reinit_led_config(uci)
+
+local function sysconfig_ifname_swap(input_ifnames)
+	local output_ifnames = {}
+	for v in input_ifnames:gmatch('%S+') do
+		if string.match(v, 'eth0') then
+			table.insert(output_ifnames, v:gsub('eth0', 'eth1'))
+		elseif string.match(v, 'eth1') then
+			table.insert(output_ifnames, v:gsub('eth1', 'eth0'))
+		end
+	end
+
+	return table.concat(output_ifnames, ' ')
+end
+
+-- For devices with embedded FE switch, eth0 and eth1
+-- have been swapped.
+local function perform_eth_swap()
+	-- Modify running config
+	uci:foreach('network', 'interface', function(iface)
+		local interfaces = uci:get_list('network', iface['.name'], 'ifname')
+		if interfaces == nil then return end
+
+		local new_interfaces = {}
+
+		for _, v in ipairs(interfaces) do
+			if string.match(v, 'eth0') then
+				table.insert(new_interfaces, v:gsub('eth0', 'eth1'))
+			elseif string.match(v, 'eth1') then
+				table.insert(new_interfaces, v:gsub('eth1', 'eth0'))
+			end
+		end
+
+		uci:set_list('network', iface['.name'], 'ifname', new_interfaces)
+	end)
+	uci:save('network')
+
+	-- Modify Gluons port assignment. Important for setup-mode.
+	sysconfig.lan_ifname = sysconfig_ifname_swap(sysconfig.lan_ifname)
+	sysconfig.wan_ifname = sysconfig_ifname_swap(sysconfig.wan_ifname)
+end
+
+local function board_requires_eth_swap()
+	local board_name = platform.get_board_name()
+	for _, v in ipairs(migration_target_config) do
+		if board_name == v[0] and v[1] then
+			return true
+		end
+	end
+	return false
+end
+
+-- Perform eth swap
+if board_requires_eth_swap() then
+	perform_eth_swap()
+end
+
+-- Flag migration done
+migration.flag_migration_done(migration_name)

package/gluon-core/luasrc/usr/lib/lua/gluon/migration.lua

@@ -0,0 +1,37 @@
+local unistd = require 'posix.unistd'
+
+
+local M = {}
+
+function M.get_migration_flag_path(migration_name)
+	return '/lib/gluon/core/migration/flags' .. migration_name
+end
+
+function M.is_migration_done(migration_name)
+	return unistd.access(M.get_migration_flag_path(migration_name))
+end
+
+function M.flag_migration_done(migration_name)
+	os.execute(M.get_migration_flag_path(migration_name))
+end
+
+function M.reinit_led_config(uci)
+	-- Remove LED configuration
+	uci:foreach('system', 'rssid', function(config)
+		uci:delete('system', config['.name'])
+	end)
+	uci:foreach('system', 'led', function(config)
+		uci:delete('system', config['.name'])
+	end)
+	uci:save('led')
+
+	-- Create LED configuration
+	os.execute('/lib/gluon/core/migration/create_led_config.sh')
+end
+
+function M.reinit_board_json()
+	os.execute('rm /etc/board.json')
+	os.execute('board_detect')
+end
+
+return M