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lualoader: add support for .lua configuration files

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If a file is specified in loader_conf_files that ends in '.lua', lualoader
will now load and execute that file. These may be used in place of a
traditional loader.conf to use more complicated logic, where some values
may be set based on others or based on the environment that the C bits has
left us with.

Lua scripts are run in a limited environment. In particular, it does not get
access to any modules or, in-fact, anything except environment variable.

A config.buildenv hook has been added so that a local module can add
whatever it may need to to the environment.

When a global var is set in the lua script, it does not immediately alter
the loader environment. Instead, the script's environment is initially
empty and processed only if the whole script executes successfully.
Effectively, a lua configuration file either takes effect or it does not,
an error will not leave it in a half-baked state.

Reviewed by:	bcr (manpages), imp
Differential Revision:	https://reviews.freebsd.org/D28450
This commit is contained in:
Kyle Evans 2023-05-10 23:10:53 -05:00
parent b6d3a9644d
commit 3cb2f5f369
7 changed files with 175 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
stand/defaults/loader.conf.5
View File

@ -427,10 +427,13 @@ It is not available in the default Forth-based loader.
default settings \(em do not change this file.
.It Pa /boot/loader.conf
user defined settings.
.It Pa /boot/loader.conf.lua
user defined settings written in lua.
.It Pa /boot/loader.conf.local
machine-specific settings for sites with a common loader.conf.
.El
.Sh SEE ALSO
.Xr loader.conf.lua 5 ,
.Xr rc.conf 5 ,
.Xr boot 8 ,
.Xr cpucontrol 8 ,

3
stand/lua/Makefile
View File

@ -2,7 +2,8 @@
.include <bsd.init.mk>
MAN= cli.lua.8 \
MAN= loader.conf.lua.5 \
cli.lua.8 \
color.lua.8 \
config.lua.8 \
core.lua.8 \

90
stand/lua/config.lua
View File

@ -45,6 +45,7 @@ local MSG_FAILSETENV = "Failed to '%s' with value: %s"
local MSG_FAILOPENCFG = "Failed to open config: '%s'"
local MSG_FAILREADCFG = "Failed to read config: '%s'"
local MSG_FAILPARSECFG = "Failed to parse config: '%s'"
local MSG_FAILEXECLUA = "Failed to execute lua conf '%s': '%s'"
local MSG_FAILPARSEVAR = "Failed to parse variable '%s': %s"
local MSG_FAILEXBEF = "Failed to execute '%s' before loading '%s'"
local MSG_FAILEXAF = "Failed to execute '%s' after loading '%s'"
@ -244,13 +245,15 @@ end
--
local pattern_table = {
{
luaexempt = true,
str = "(#.*)",
process = function(_, _) end,
groups = 1,
},
-- module_load="value"
{
str = MODULEEXPR .. "_load%s*=%s*$VALUE",
name = MODULEEXPR .. "_load%s*",
val = "%s*$VALUE",
process = function(k, v)
if modules[k] == nil then
modules[k] = {}
@ -261,7 +264,8 @@ local pattern_table = {
},
-- module_name="value"
{
str = MODULEEXPR .. "_name%s*=%s*$VALUE",
name = MODULEEXPR .. "_name%s*",
val = "%s*$VALUE",
process = function(k, v)
setKey(k, "name", v)
setEnv(k .. "_name", v)
@ -269,7 +273,8 @@ local pattern_table = {
},
-- module_type="value"
{
str = MODULEEXPR .. "_type%s*=%s*$VALUE",
name = MODULEEXPR .. "_type%s*",
val = "%s*$VALUE",
process = function(k, v)
setKey(k, "type", v)
setEnv(k .. "_type", v)
@ -277,7 +282,8 @@ local pattern_table = {
},
-- module_flags="value"
{
str = MODULEEXPR .. "_flags%s*=%s*$VALUE",
name = MODULEEXPR .. "_flags%s*",
val = "%s*$VALUE",
process = function(k, v)
setKey(k, "flags", v)
setEnv(k .. "_flags", v)
@ -285,7 +291,8 @@ local pattern_table = {
},
-- module_before="value"
{
str = MODULEEXPR .. "_before%s*=%s*$VALUE",
name = MODULEEXPR .. "_before%s*",
val = "%s*$VALUE",
process = function(k, v)
setKey(k, "before", v)
setEnv(k .. "_before", v)
@ -293,7 +300,8 @@ local pattern_table = {
},
-- module_after="value"
{
str = MODULEEXPR .. "_after%s*=%s*$VALUE",
name = MODULEEXPR .. "_after%s*",
val = "%s*$VALUE",
process = function(k, v)
setKey(k, "after", v)
setEnv(k .. "_after", v)
@ -301,7 +309,8 @@ local pattern_table = {
},
-- module_error="value"
{
str = MODULEEXPR .. "_error%s*=%s*$VALUE",
name = MODULEEXPR .. "_error%s*",
val = "%s*$VALUE",
process = function(k, v)
setKey(k, "error", v)
setEnv(k .. "_error", v)
@ -309,7 +318,9 @@ local pattern_table = {
},
-- exec="command"
{
str = "exec%s*=%s*" .. QVALEXPR,
luaexempt = true,
name = "exec%s*",
val = "%s*" .. QVALEXPR,
process = function(k, _)
if cli_execute_unparsed(k) ~= 0 then
print(MSG_FAILEXEC:format(k))
@ -319,7 +330,8 @@ local pattern_table = {
},
-- env_var="value" or env_var=[word|num]
{
str = "([%w][%w%d-_.]*)%s*=%s*$VALUE",
name = "([%w][%w%d-_.]*)%s*",
val = "%s*$VALUE",
process = function(k, v)
local pv, msg = processEnvVar(v)
if not pv then
@ -328,6 +340,8 @@ local pattern_table = {
end
if setEnv(k, pv) ~= 0 then
print(MSG_FAILSETENV:format(k, v))
else
return pv
end
end,
},
@ -486,6 +500,18 @@ local function checkNextboot()
loader.setenv("nextboot_enable", "NO")
end
local function processEnv(k, v)
for _, val in ipairs(pattern_table) do
if not val.luaexempt and val.name then
local matched = k:match(val.name)
if matched then
return val.process(matched, v)
end
end
end
end
-- Module exports
config.verbose = false
@ -511,7 +537,47 @@ function config.processFile(name, silent)
return silent
end
return config.parse(text)
if name:match(".lua$") then
local cfg_env = setmetatable({}, {
indices = {},
__index = function(env, key)
if getmetatable(env).indices[key] then
return rawget(env, key)
end
return loader.getenv(key)
end,
__newindex = function(env, key, val)
getmetatable(env).indices[key] = true
rawset(env, key, val)
end,
})
-- Give local modules a chance to populate the config
-- environment.
hook.runAll("config.buildenv", cfg_env)
local res, err = pcall(load(text, name, "t", cfg_env))
if res then
for k, v in pairs(cfg_env) do
local t = type(v)
if t ~= "function" and t ~= "table" then
if t ~= "string" then
v = tostring(v)
end
local pval = processEnv(k, v)
if pval then
setEnv(k, pval)
end
end
end
else
print(MSG_FAILEXECLUA:format(name, err))
end
return res
else
return config.parse(text)
end
end
-- silent runs will not return false if we fail to open the file
@ -522,6 +588,9 @@ function config.parse(text)
for line in text:gmatch("([^\n]+)") do
if line:match("^%s*$") == nil then
for _, val in ipairs(pattern_table) do
if val.str == nil then
val.str = val.name .. "=" .. val.val
end
local pattern = '^%s*' .. val.str .. '%s*(.*)';
local cgroups = val.groups or 2
local k, v, c = checkPattern(line, pattern)
@ -805,6 +874,7 @@ function config.getModuleInfo()
}
end
hook.registerType("config.buildenv")
hook.registerType("config.loaded")
hook.registerType("config.reloaded")
hook.registerType("kernel.loaded")

8
stand/lua/config.lua.8
View File

@ -217,11 +217,19 @@ as well as a representation of
The following hooks are defined in
.Nm :
.Bl -tag -width "config.reloaded" -offset indent
.It Fn config.buildenv env
.It Fn config.loaded
.It Fn config.reloaded
.It Fn kernel.loaded
.It Fn modules.loaded
.El
.Pp
Note that the
.Fn config.buildenv
hook is only invoked when an environment needs to be built to execute a lua
configuration file that has been specified in
.Ev loader_conf_files .
It will be invoked for each configuration file encountered.
.Sh SEE ALSO
.Xr loader.conf 5 ,
.Xr loader 8 ,

4
stand/lua/hook.lua
View File

@ -60,7 +60,7 @@ end
-- Takes a hooktype and runs all functions associated with that specific hook
-- type in the order that they were registered in. This ordering should likely
-- not be relied upon.
function hook.runAll(hooktype)
function hook.runAll(hooktype, data)
local selected_hooks = registered_hooks[hooktype]
if selected_hooks == nil then
-- This message, and the print() above, should only be seen by
@ -74,7 +74,7 @@ function hook.runAll(hooktype)
end
if #selected_hooks > 0 then
for _, func in ipairs(selected_hooks) do
func()
func(data)
end
end
return #selected_hooks

4
stand/lua/hook.lua.8
View File

@ -26,7 +26,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd June 9, 2018
.Dd April 28, 2020
.Dt HOOK.LUA 8
.Os
.Sh NAME
@ -39,6 +39,8 @@ Hooks are functions used to attach custom behaviors at pre-defined points in
loader execution.
These pre-defined points are what we refer to as
.Dq hook types .
Hooks may also take an optional data parameter, which may or may not be
populated by the caller.
.Pp
Before using the functionality provided by
.Nm ,

77
stand/lua/loader.conf.lua.5 Normal file
View File

@ -0,0 +1,77 @@
.\"
.\" SPDX-License-Identifier: BSD-2-Clause-FreeBSD
.\"
.\" Copyright (c) 2020 Kyle Evans <kevans@FreeBSD.org>
.\"
.\" 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.
.\"
.\" $FreeBSD$
.\"
.Dd May 10, 2023
.Dt LOADER.CONF.LUA 5
.Os
.Sh NAME
.Nm loader.conf.lua
.Nd Lua-based system bootstrap configuration file
.Sh DESCRIPTION
When the lua-based
.Xr loader 8
encounters a filename in
.Va loader_conf_files
that has a
.Dq .lua
suffix, it will be loaded and executed by the lua interpreter in a limited
environment.
.Pp
The limited environment does not contain the ability to reference or load other
lua modules.
Existing loader environment variables may be referenced as if they were already
defined global variables.
.Pp
A lua configuration file may set any global variable, which will subsequently
be processed and added to the environment after execution of the configuration
file has completed.
Other than the
.Ar exec
setting, all variables described in
.Xr loader.conf 5
operate the same in the
.Nm
environment.
Note that the settings describing module options can only be set in the
environment; there is currently no way for a
.Pa loader.conf.lua
to fetch them.
At this time, global table and function values are ignored.
.Pp
The
.Fn config.buildenv
hook will be run with an empty environment provided to it that may be populated
by a custom
.Pa local.lua .
.Sh SEE ALSO
.Xr loader.conf 5
.Sh AUTHORS
The mechanism for loading
.Nm
files was originally written by
.An Kyle Evans Aq Mt kevans@FreeBSD.org .