3cb2f5f369
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
97 lines
3.2 KiB
Groff
97 lines
3.2 KiB
Groff
.\"
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.\" SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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.\"
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.\" Copyright (c) 2018 Kyle Evans <kevans@FreeBSD.org>
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd April 28, 2020
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.Dt HOOK.LUA 8
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.Os
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.Sh NAME
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.Nm hook.lua
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.Nd FreeBSD hook module
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.Sh DESCRIPTION
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.Nm
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contains functionality for defining hook types and attaching hooks.
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Hooks are functions used to attach custom behaviors at pre-defined points in
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loader execution.
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These pre-defined points are what we refer to as
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.Dq hook types .
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Hooks may also take an optional data parameter, which may or may not be
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populated by the caller.
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.Pp
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Before using the functionality provided by
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.Nm ,
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it must be included with a statement such as the following:
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.Pp
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.Dl local hook = require("hook")
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.Ss Exported functions
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The following functions are exported from
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.Nm :
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.Bl -tag -width hook.registerType -offset indent
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.It Fn hook.registerType hooktype
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Adds
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.Ev hooktype
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as a recognized hook type.
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This allows functions to be added to run when hooks of this type are invoked
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using
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.Fn hook.runAll hooktype .
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.It Fn hook.register hooktype hookfunc
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Register
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.Ev hookfunc
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to be run when hooks of type
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.Ev hooktype
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are invoked.
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.It Fn hook.runAll hooktype
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Invoke all hooks registered for type
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.Ev hooktype .
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Hooks are invoked in the order in which they are registered.
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.El
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.Ss Hook Naming Guidelines
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Hook names should consist of the name of the module they are defined in, as well
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as a verb describing when the hook is executed, separated by a period.
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For example,
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.Dq config.reloaded
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is defined in the
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.Xr config.lua 8
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module and run when the configuration is reloaded.
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.Sh EXAMPLES
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To register a hook to be run when configuration is reloaded:
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.Pp
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.Bd -literal -offset indent -compact
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local hook = require("hook")
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local function configuration_was_reloaded()
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print("Configuration was reloaded!")
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end
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hook.register("config.reloaded", configuration_was_reloaded)
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.Ed
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.Sh AUTHORS
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The
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.Nm
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file was originally written by
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.An Kyle Evans Aq Mt kevans@FreeBSD.org .
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