diff --git a/stand/man/loader_lua.8 b/stand/man/loader_lua.8 index 3bc7985ea00a..adf2bca6be14 100644 --- a/stand/man/loader_lua.8 +++ b/stand/man/loader_lua.8 @@ -1,266 +1,266 @@ .\" Copyright (c) 1999 Daniel C. Sobral .\" 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. .\" .\" $FreeBSD$ .\" .Dd September 29, 2021 .Dt LOADER_LUA 8 .Os .Sh NAME .Nm loader_lua .Nd kernel bootstrapping final stage .Sh DESCRIPTION The program called .Nm is the final stage of .Fx Ns 's kernel bootstrapping process. On IA32 (i386) architectures, it is a .Pa BTX client. It is linked statically to .Xr libstand 3 and usually located in the directory .Pa /boot . .Pp It provides a scripting language that can be used to automate tasks, do pre-configuration or assist in recovery procedures. This scripting language is roughly divided in two main components. The smaller one is a set of commands designed for direct use by the casual user, called "builtin commands" for historical reasons. The main drive behind these commands is user-friendliness. The bigger component is the Lua interpreter. .Pp During initialization, .Nm -probes for a console and set the +probes for a console and sets the .Va console -variable, or set it to serial console +variable, or sets it to serial console .Pq Dq Li comconsole if the previous boot stage used that. If multiple consoles are selected, they are listed separated by spaces. Then, devices are probed, .Va currdev and .Va loaddev are set, and .Va LINES is set to 24. Next, Lua is initialized, and .Pa /boot/lua/loader.lua is processed if it exists. After that, .Pa /boot/loader.conf is processed if available. .Pp At this point, if an .Ic autoboot -has not been tried, and if +has not been attempted, and if .Va autoboot_delay is not set to .Dq Li NO -(not case sensitive), then an +(case insensitive), then an .Ic autoboot is attempted. If the system gets past this point, .Va prompt is set and .Nm enters interactive mode. Please note that, historically, even when .Va autoboot_delay is set to .Dq Li 0 , the user can interrupt the autoboot process by pressing a key on the console while the kernel and modules are being loaded. To prevent this set .Va autoboot_delay to .Dq Li -1 . In this case .Nm enters interactive mode only if .Ic autoboot has failed. .Sh BUILTIN COMMANDS In .Nm , builtin commands take parameters from the command line. Presently, the only way to call them from a script is by using .Pa evaluate on a string. If an error condition occurs, an exception is generated, which can be intercepted using Lua exception handling. If not intercepted, an error message is displayed and the interpreter's state is reset, emptying the stack and restoring interpreting mode. .Pp The commands are described in the .Xr loader_simp 8 .Dq BUILTIN COMMANDS section. .Ss BUILTIN ENVIRONMENT VARIABLES The environment variables common to all interpreters are described in the .Xr loader_simp 8 .Dq BUILTIN ENVIRONMENT VARIABLES section. .Ss BUILTIN PARSER When a builtin command is executed, the rest of the line is taken -by it as arguments, and it is processed by a special parser which +as arguments, and it is processed by a special parser which is not used for regular Lua commands. .Sh SECURITY Access to the .Nm command line provides several ways of compromising system security, including, but not limited to: .Pp .Bl -bullet .It Booting from removable storage, by setting the .Va currdev or .Va loaddev variables .It -Executing binary of choice, by setting the +Executing a binary of choice, by setting the .Va init_path or .Va init_script variables .It Overriding ACPI DSDT to inject arbitrary code into the ACPI subsystem .El .Pp One can prevent unauthorized access to the .Nm command line by setting the .Va password , or setting .Va autoboot_delay to -1. See .Xr loader.conf 5 for details. In order for this to be effective, one should also configure the firmware (BIOS or UEFI) to prevent booting from unauthorized devices. .Sh MD Memory disk (MD) can be used when the .Nm was compiled with .Va MD_IMAGE_SIZE . The size of the memory disk is determined by .Va MD_IMAGE_SIZE . If MD available, a file system can be embedded into the .Nm with .Pa /sys/tools/embed_mfs.sh . -Then, MD is probed and be set to +Then, MD is probed and set to .Va currdev during initialization. .Pp Currently, MD is only supported in .Xr loader.efi 8 . .Sh FILES .Bl -tag -width /usr/share/examples/bootforth/ -compact .It Pa /boot/loader .Nm itself. .It Pa /boot/defaults/loader.conf .It Pa /boot/lua/loader.lua Loader init .It Pa /boot/loader.conf .It Pa /boot/loader.conf.local .Nm configuration files, as described in .Xr loader.conf 5 . .Sh EXAMPLES Boot in single user mode: .Pp .Dl boot -s .Pp Load the kernel, a splash screen, and then autoboot in five seconds. Notice that a kernel must be loaded before any other .Ic load command is attempted. .Bd -literal -offset indent load kernel load splash_bmp load -t splash_image_data /boot/chuckrulez.bmp autoboot 5 .Ed .Pp Set the disk unit of the root device to 2, and then boot. This would be needed in a system with two IDE disks, with the second IDE disk hardwired to ada2 instead of ada1. .Bd -literal -offset indent set root_disk_unit=2 boot /boot/kernel/kernel .Ed .Pp Set the default device used for loading a kernel from a ZFS filesystem: .Bd -literal -offset indent set currdev=zfs:tank/ROOT/knowngood: .Ed .Pp .Sh ERRORS The following values are thrown by .Nm : .Bl -tag -width XXXXX -offset indent .It 100 Any type of error in the processing of a builtin. .It -1 .Ic Abort executed. .It -2 .Ic Abort" executed. .It -56 .Ic Quit executed. .It -256 Out of interpreting text. .It -257 Need more text to succeed -- will finish on next run. .It -258 .Ic Bye executed. .It -259 Unspecified error. .El .Sh SEE ALSO .Xr libstand 3 , .Xr loader.conf 5 , .Xr tuning 7 , .Xr boot 8 , .Xr btxld 8 .Sh HISTORY The .Nm first appeared in .Fx 12.0 .