A static build of Lua 5.3 for Linux, with a few extension libraries.

Additional libraries are pre-loaded. They must be require()'d before use (see lua/src/linit.c)

• lfs (from LuaFileSystem)
• luazen (a small library with basic crypto and compression functions)
• nacl (the NaCl crypto library, from Dan Bernstein et al. This small Lua wrapper is based on the tweet nacl implementation which is also included)
• minisock (a minimal socket library for tcp connections)
• luaproc (multi-threading library)
• linenoise (slua is built on Linux with linenoise to replace readline. A limited Lua binding to linenoise is also provided to allow usage of linenoise in applications)

Some documentation and references about these libraries is available in doc/all_libraries.md and directory doc.

slua is linked completely statically. It uses no dynamic library, not even libc.

It can be used anywhere, whatever the platform dynamic linker. The Linux x86 version is built with the Musl C library which allows a very compact executable. If built in a x86 (32-bit) environment, it can be run on any Linux system (x86 or x86_64)

It can be dropped and run from any directory, without interference or dynamic library incompatibilities. Defaults paths ("package.path") are limited to the current directory to minimize the risk of "catching" Lua files at the standard locations, intended to be used by a regular, installed Lua.

On the other end, obviously, slua cannot load dynamic C libraries. It is not intended to be a replacement for a full fledged Lua installation.

It is possible to append Lua code to the slua executable. The appended code will be run by slua before entering the Lua REPL (this is similar to 'lua -i somecode.lua').

If entering the REPL is not wanted, the appended code can just be ended with "os.exit()".

The appended code must start with the following exact string: "--slua appended code", ending with a newline.

Then it is enough to:

	cp slua my_program
	cat some_code.lua >> my_program

If some_code.lua does not start with the magic string, it is easy to add it. For example let's build a standalone program that runs the nacl test (in test/) and exits:

	cp slua my_nacl_test
	echo "--slua appended code" >>my_nacl_test
	cat test/test_nacl.lua >> my_nacl_test
	echo "os.exit()" >>my_nacl_test

Then ./my_nacl_test will just run the test.

The append code mechanism within slua is itself written in Lua (see src/sluacode.c). It is invoked in src/slua.c (after comment "/// slua embedded Lua code").

It can be easily modified --in Lua!-- to, for example, load compressed or encrypted code. Or for anything else.

To build slua on Linux, just adjust the 'Makefile' (eg. to compile with Musl libc, the CC variable must be set to the path of the 'musl-gcc' wrapper), run 'make' at the root of the source tree.

There is no installation. The slua binary can be placed and executed anywhere.

The default Lua paths ('package.path' and 'package.cpath') have been modified. The default Lua path points only to the current directory, and the (unused) Lua cpath is empty.

• package.path: "./?.lua;./?/init.lua"
• package.cpath: ""

slua still respects the environment variables LUA_PATH and LUA_CPATH.

To build slua:

	# adjust the CC variable in the Makefile, then:
    make

Binary versions of slua may be provided here for convenience.

Musl libc - A script is provided to fetch and build musl libc and the required Linux headers. See tools/build_musl.sh and comments at the beginning of the script.

Dynamic linking version - A makefile to build 'sglua', a dynamic version of slua, with the same additional libraries statically linked and preloaded. 'sglua' has the same functions as slua (built-in linenoise line-editing, execution of appended lua code). It is intended to be built with the regular glibc (so the only runtime dependencies are libc, libm, libpthread and libdl). Additional C libraries can be loaded with 'require()'.

For 'sglua', the default Lua paths are slightly different:

• package.path: "lua;./?/init.lua"
• package.cpath: "./?.so"

To build sglua:

    make -f Makefile.glibc

Lua 5.3.3 - http://www.lua.org/ftp/lua-5.3.3.tar.gz

LuaFileSystem 1.6.3 - commit 6d039ff385 - https://github.com/keplerproject/luafilesystem

Luaproc 1.0.4 - commit 990ecf6, Oct 20, 2015 - https://github.com/askyrme/luaproc

The full readline library is not used. It is replaced by the much smaller linenoise library. The linenoise implementation included here has been extended to include a Lua binding. It is derived from Linenoise v1.0 - commit 027dbce - https://github.com/antirez/linenoise

Musl libc - slua has been built against musl-1.1.10 and 1.1.14 on x86, and musl-1.1.12 on arm.

src/lua/luaconf.h:

• modification of LUA_PATH_DEFAULT and LUA_CPATH_DEFAULT

src/lua/linit.c - not used. It is replaced with src/linit.c

• addition of the preloaded libraries

src/lua/lua.c - not used. It is replaced with src/slua.c

• replacement of readline with linenoise
• extension mechanism (see above)

The Linux x86 binary version of slua has been built on a x86_64 (64-bit) platform with the Musl C library (version 1.1.14)

I am of course grateful to the PUC-Rio team for the wonderful Lua.

Although their objectives are different, slua has been inspired by other projects:

• MurgaLua, by John Murga - http://www.murga-projects.com/murgaLua.html
• BonaLuna, by Christophe Delord - http://www.cdsoft.fr/bl/bonaluna.html
• Luabuild, by Steve Donovan, which is a more ambitious tool to build a static Lua with bundled libraries - https://github.com/stevedonovan/luabuild

Other related projects

• Luastatic - https://github.com/ers35/luastatic
• Omnia (based on Luastatic) - https://github.com/tongson/omnia

Lua and all extension libraries are distributed under the terms of their respective licenses (MIT or equivalent). See LICENSE files in directories lua, and luafilesystem.

The "tweet" NaCl core implementation is public domain, by Daniel Bernstein et al.

The luazen library includes some code from various authors (see src/luazen):

• base64 functions by Luiz Henrique de Figueiredo (public domain)
• base58 functions by Luke Dashjr (MIT)
• md5, sha1 by Cameron Rich (BSD)

Luazen, minisock, the tweetnacl Lua wrapper are distributed under the MIT License (see file LICENSE)

Copyright (c) 2016 Phil Leblanc