userboot: handle guest interpreter mismatches more intelligently

The switch to lualoader creates a problem with userboot: the host is
inclined to build userboot with Lua, but the host userboot's int

userboot: handle guest interpreter mismatches more intelligently

The switch to lualoader creates a problem with userboot: the host is
inclined to build userboot with Lua, but the host userboot's interpreter
must match what's available on the guest. For almost all FreeBSD guests in
the wild, Lua is not yet available and a Lua-based userboot will fail.

This revision updates userboot protocol to version 5, which adds a
swap_interpreter callback to request a different interpreter, and tries to
determine the proper interpreter to be used based on how the guest
/boot/loader is compiled. This is still a bit of a guess, but it's likely
the best possible guess we can make in order to get it right. The
interpreter is now embedded in the resulting executable, so we can open
/boot/loader on the guest and hunt that down to derive the interpreter it
was built with.

Using -l with bhyveload will not allow an intepreter swap, even if the
loader specified happens to be a userboot with the wrong interpreter. We'll
simply complain about the mismatch and bail out.

For legacy guests without the interpreter marker, we assume they're 4th.
For new guests with the interpreter marker, we'll read it and swap over
to the proper interpreter if it doesn't match what the userboot we're using
was compiled with.

Both flavors of userboot are installed by default, userboot_4th.so and
userboot_lua.so. This fixes the build WITHOUT_FORTH as a coincidence, which
was broken by userboot being forced to 4th.

Reviewed by: imp, jhb, araujo (earlier version)
Approved by: re (gjb)
Differential Revision: https://reviews.freebsd.org/D16945

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lualoader: Print error messages from command failures at the prompt

Previously lualoader would remain silent, rather than printing
command_errmsg or noting that a command had failed or was not found

lualoader: Print error messages from command failures at the prompt

Previously lualoader would remain silent, rather than printing
command_errmsg or noting that a command had failed or was not found.

Approved by: re (gjb)

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stand/interp_lua: correct errorr => error

loader.lua: Expose errno table to lua

Reviewed by: kevans
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D14454

lualoader: Add ability to intercept cli commands

If we failed to execute the input line as pure lua, run the command through
parse for consistent argument parsing. Pass the parsed arguments through

lualoader: Add ability to intercept cli commands

If we failed to execute the input line as pure lua, run the command through
parse for consistent argument parsing. Pass the parsed arguments through to
a global "cli_execute" written in Lua, which is expected to either handle it
or pass it back through to interp_builtin_cmd (via loader.command).

lua-handled cli commands will then exist as globals in whatever module they
most belong in, and invocations at the loader prompt will magically dispatch
to them if they exist.

Reviewed by: imp
Differential Revision: https://reviews.freebsd.org/D14450

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Lua loader: Add barebones "lfs" module

Add a Lua FileSystem module, an emulation of a subset of the permissively
licensed (MIT) Lua library of the same name[0], to our loader's Lua
environment.

[0]

Lua loader: Add barebones "lfs" module

Add a Lua FileSystem module, an emulation of a subset of the permissively
licensed (MIT) Lua library of the same name[0], to our loader's Lua
environment.

[0]: https://github.com/keplerproject/luafilesystem/

Reviewed by: kevans
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D14418

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interp_lua: Register io/loader with regular Lua module system

Reviewed by: kevans
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D14421

Add Lua as a scripting langauge to /boot/loader

liblua glues the lua run time into the boot loader. It implements all
the runtime routines that lua expects. In addition, it has a few
standard 'C' he

Add Lua as a scripting langauge to /boot/loader

liblua glues the lua run time into the boot loader. It implements all
the runtime routines that lua expects. In addition, it has a few
standard 'C' headers that nueter various aspects of the LUA build that
are too specific to lua to be in libsa. Many refinements from the
original code to improve implementation and the number of included lua
libraries. Use int64_t for lua_Number. Have "/boot/lua" be the default
module path. Numerous cleanups from the original GSoC project,
including hacking libsa to allow lua to be built with only one change
outside luaconf.h.

Add the final bit of lua glue to bring in liblua and plug into the
multiple interpreter framework, previously committed.

Add LOADER_LUA option, currently off by default.

Presently, this is an experimental option. One must opt-in to using
this by defining WITH_LOADER_LUA and WITHOUT_FORTH. It's been
lightly tested, so keep a backup copy of your old loader handy.
The menu code, coming in the next commit, hasn't been exhaustively
tested. A LUA boot loader is 60k larger than a FORTH one, which is
80k larger than a no-interpreter one. Subtle changes in size
may tip things past some subtle limit (the binary is ~430k now
when built with LUA). A future version may offer coexistance.

Bump FreeBSD version to 1200058 to mark the milestone.

Pedro Souza's 2014 Summer of Code project. Rui Paulo, Pedro Arthur,
Zakary Nafziger and Wojciech A. Koszek also contributed. Warner Losh
reworked it extensively into its current form.

Obtained from: https://wiki.freebsd.org/SummerOfCode2014/LuaLoader
Sponsored by: Google Summer of Code
Relnotes: Yes
MFC After: 1 month
Differential Review: https://reviews.freebsd.org/D14295

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