freebsd-skq/stand/lua/config.lua

--
-- Copyright (c) 2015 Pedro Souza <pedrosouza@freebsd.org>
-- All rights reserved.
--
-- Redistribution and use in source and binary forms, with or without
-- modification, are permitted provided that the following conditions
-- are met:
-- 1. Redistributions of source code must retain the above copyright
--    notice, this list of conditions and the following disclaimer.
-- 2. Redistributions in binary form must reproduce the above copyright
--    notice, this list of conditions and the following disclaimer in the
--    documentation and/or other materials provided with the distribution.
--
-- THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
-- ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-- IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
-- ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
-- FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
-- DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
-- OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
-- HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
-- LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
-- OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
-- SUCH DAMAGE.
--
-- $FreeBSD$
--

local config = {};
-- Which variables we changed
config.env_changed = {};
-- Values to restore env to (nil to unset)
config.env_restore = {};

local modules = {};

function config.restoreEnv()
	for k, v in pairs(config.env_changed) do
		local restore_value = config.env_restore[k];
		if (restore_value ~= nil) then
			loader.setenv(k, restore_value);
		else
			loader.unsetenv(k);
		end
	end

	config.env_changed = {};
	config.env_restore = {};
end

function config.setenv(k, v)
	-- Do we need to track this change?
	if (config.env_changed[k] == nil) then
		config.env_changed[k] = true;
		config.env_restore[k] = loader.getenv(k);
	end

	return loader.setenv(k, v);
end

function config.setKey(k, n, v)
	if (modules[k] == nil) then
		modules[k] = {};
	end
	modules[k][n] = v;
end

function config.lsModules()
	print("== Listing modules");
	for k, v in pairs(modules) do
		print(k, v.load);
	end
	print("== List of modules ended");
end

local pattern_table = {
	[1] = {
		str = "^%s*(#.*)",
		process = function(k, v)  end
	},
	--  module_load="value"
	[2] = {
		str = "^%s*([%w_]+)_load%s*=%s*\"([%w%s%p]-)\"%s*(.*)",
		process = function(k, v)
			if (modules[k] == nil) then
				modules[k] = {};
			end
			modules[k].load = v:upper();
		end
	},
	--  module_name="value"
	[3] = {
		str = "^%s*([%w_]+)_name%s*=%s*\"([%w%s%p]-)\"%s*(.*)",
		process = function(k, v)
			config.setKey(k, "name", v);
		end
	},
	--  module_type="value"
	[4] = {
		str = "^%s*([%w_]+)_type%s*=%s*\"([%w%s%p]-)\"%s*(.*)",
		process = function(k, v)
			config.setKey(k, "type", v);
		end
	},
	--  module_flags="value"
	[5] = {
		str = "^%s*([%w_]+)_flags%s*=%s*\"([%w%s%p]-)\"%s*(.*)",
		process = function(k, v)
			config.setKey(k, "flags", v);
		end
	},
	--  module_before="value"
	[6] = {
		str = "^%s*([%w_]+)_before%s*=%s*\"([%w%s%p]-)\"%s*(.*)",
		process = function(k, v)
			config.setKey(k, "before", v);
		end
	},
	--  module_after="value"
	[7] = {
		str = "^%s*([%w_]+)_after%s*=%s*\"([%w%s%p]-)\"%s*(.*)",
		process = function(k, v)
			config.setKey(k, "after", v);
		end
	},
	--  module_error="value"
	[8] = {
		str = "^%s*([%w_]+)_error%s*=%s*\"([%w%s%p]-)\"%s*(.*)",
		process = function(k, v)
			config.setKey(k, "error", v);
		end
	},
	--  exec="command"
	[9] = {
		str = "^%s*exec%s*=%s*\"([%w%s%p]-)\"%s*(.*)",
		process = function(k, v)
			if (loader.perform(k) ~= 0) then
				print("Failed to exec '" .. k .. "'");
			end
		end
	},
	--  env_var="value"
	[10] = {
		str = "^%s*([%w%p]+)%s*=%s*\"([%w%s%p]-)\"%s*(.*)",
		process = function(k, v)
			if (config.setenv(k, v) ~= 0) then
				print("Failed to set '" .. k ..
				    "' with value: " .. v .. "");
			end
		end
	},
	--  env_var=num
	[11] = {
		str = "^%s*([%w%p]+)%s*=%s*(%d+)%s*(.*)",
		process = function(k, v)
			if (config.setenv(k, v) ~= 0) then
				print("Failed to set '" .. k ..
				    "' with value: " .. v .. "");
			end
		end
	}
};

function config.isValidComment(c)
	if (c ~= nil) then
		local s = c:match("^%s*#.*");
		if (s == nil) then
			s = c:match("^%s*$");
		end
		if (s == nil) then
			return false;
		end
	end
	return true;
end

function config.loadmod(mod, silent)
	local status = true;
	for k, v in pairs(mod) do
		if (v.load == "YES") then
			local str = "load ";
			if (v.flags ~= nil) then
				str = str .. v.flags .. " ";
			end
			if (v.type ~= nil) then
				str = str .. "-t " .. v.type .. " ";
			end
			if (v.name ~= nil) then
				str = str .. v.name;
			else
				str = str .. k;
			end

			if (v.before ~= nil) then
				if (loader.perform(v.before) ~= 0) then
					if (not silent) then
						print("Failed to execute '" ..
						    v.before ..
						    "' before loading '".. k ..
						    "'");
					end
					status = false;
				end
			end

			if (loader.perform(str) ~= 0) then
				if (not silent) then
					print("Failed to execute '" .. str ..
					    "'");
				end
				if (v.error ~= nil) then
					loader.perform(v.error);
				end
				status = false;
			end

			if (v.after ~= nil) then
				if (loader.perform(v.after) ~= 0) then
					if (not silent) then
						print("Failed to execute '" ..
						    v.after ..
						    "' after loading '" .. k ..
						    "'");
					end
					status = false;
				end
			end

		else
			--if not silent then print("Skiping module '".. k .. "'"); end
		end
	end

	return status;
end

function config.parse(name, silent)
	local f = io.open(name);
	if (f == nil) then
		if (not silent) then
			print("Failed to open config: '" .. name .. "'");
		end
		return false;
	end

	local text;
	local r;

	text, r = io.read(f);

	if (text == nil) then
		if (not silent) then
			print("Failed to read config: '" .. name .. "'");
		end
		return false;
	end

	local n = 1;
	local status = true;

	for line in text:gmatch("([^\n]+)") do
		if (line:match("^%s*$") == nil) then
			local found = false;

			for i, val in ipairs(pattern_table) do
				local k, v, c = line:match(val.str);
				if (k ~= nil) then
					found = true;

					if (config.isValidComment(c)) then
						val.process(k, v);
					else
						print("Malformed line (" .. n ..
						    "):\n\t'" .. line .. "'");
						status = false;
					end

					break;
				end
			end

			if (found == false) then
				print("Malformed line (" .. n .. "):\n\t'" ..
				    line .. "'");
				status = false;
			end
		end
		n = n + 1;
	end

	return status;
end

-- other_kernel is optionally the name of a kernel to load, if not the default
-- or autoloaded default from the module_path
function config.loadkernel(other_kernel)
	local flags = loader.getenv("kernel_options") or "";
	local kernel = other_kernel or loader.getenv("kernel");

	local try_load = function (names)
		for name in names:gmatch("([^;]+)%s*;?") do
			r = loader.perform("load " .. flags .. " " .. name);
			if (r == 0) then
				return name;
			end
		end
		return nil;
	end

	local load_bootfile = function()
		local bootfile = loader.getenv("bootfile");

		-- append default kernel name
		if (bootfile == nil) then
			bootfile = "kernel";
		else
			bootfile = bootfile .. ";kernel";
		end

		return try_load(bootfile);
	end

	-- kernel not set, try load from default module_path
	if (kernel == nil) then
		local res = load_bootfile();

		if (res ~= nil) then
			-- Default kernel is loaded
			config.kernel_loaded = nil;
			return true;
		else
			print("No kernel set, failed to load from module_path");
			return false;
		end
	else
		-- Use our cached module_path, so we don't end up with multiple
		-- automatically added kernel paths to our final module_path
		local module_path = config.module_path;
		local res = nil;

		if (other_kernel ~= nil) then
			kernel = other_kernel;
		end
		-- first try load kernel with module_path = /boot/${kernel}
		-- then try load with module_path=${kernel}
		local paths = {"/boot/" .. kernel, kernel};

		for k,v in pairs(paths) do
			loader.setenv("module_path", v);
			res = load_bootfile();

			-- succeeded, add path to module_path
			if (res ~= nil) then
				config.kernel_loaded = kernel;
				if (module_path ~= nil) then
					loader.setenv("module_path", v .. ";" ..
					    module_path);
				end
				return true;
			end
		end

		-- failed to load with ${kernel} as a directory
		-- try as a file
		res = try_load(kernel);
		if (res ~= nil) then
			config.kernel_loaded = kernel;
			return true;
		else
			print("Failed to load kernel '" .. kernel .. "'");
			return false;
		end
	end
end

function config.selectkernel(kernel)
	config.kernel_selected = kernel;
end

function config.load(file)
	if (not file) then
		file = "/boot/defaults/loader.conf";
	end

	if (not config.parse(file)) then
--		print("Failed to parse configuration: '" .. file .. "'");
	end

	local f = loader.getenv("loader_conf_files");
	if (f ~= nil) then
		for name in f:gmatch("([%w%p]+)%s*") do
			if (not config.parse(name)) then
--				print("Failed to parse configuration: '" ..
--				    name .. "'");
			end
		end
	end

	-- Cache the provided module_path at load time for later use
	config.module_path = loader.getenv("module_path");
end

-- Reload configuration
function config.reload(file)
	modules = {};
	config.restoreEnv();
	config.load(file);
end

function config.loadelf()
	local kernel = config.kernel_loaded or config.kernel_selected;
	local loaded = false;

	print("Loading kernel...");
	loaded = config.loadkernel(kernel);

	if (not loaded) then
		loaded = config.loadkernel();
	end

	if (not loaded) then
		-- Ultimately failed to load kernel
		print("Failed to load any kernel");
		return;
	end

	print("Loading configured modules...");
	if (not config.loadmod(modules)) then
		print("Could not load one or more modules!");
	end
end


return config