{"id":820,"date":"2015-04-05T19:49:02","date_gmt":"2015-04-05T17:49:02","guid":{"rendered":"http:\/\/lallafa.de\/blog\/?p=820"},"modified":"2015-04-05T19:49:37","modified_gmt":"2015-04-05T17:49:37","slug":"a-lua-shell-for-fs-uae","status":"publish","type":"post","link":"https:\/\/lallafa.de\/blog\/2015\/04\/a-lua-shell-for-fs-uae\/","title":{"rendered":"A lua shell for FS-UAE"},"content":{"rendered":"

While FS-UAE<\/a> recently added a scripting interface with a Lua<\/a> scripting binding, it only provides capabilities to write scripts with hooks that will be called on certain emulator events. I \u00c2\u00a0hacked this scripting interface and added a Lua remote shell<\/strong>. With this shell you can connect while the emulator is running and issue commands. I also started to add disk image related functions to the Lua binding. With these features combined I could show off the power of a scripting shell by writing a tool to insert floppy and cd-rom disk images while the emulator is running – a long awaited and missing feature…<\/p>\n

1. Build FS-UAE with the lua shell<\/h3>\n

The lua shell is for now only available as a source code patch and you need to compile a fresh FS-UAE to use it. But that is not too difficult:<\/p>\n

The code is hosted on the\u00c2\u00a0lua<\/strong> branch in my github repository:<\/p>\n

https:\/\/github.com\/cnvogelg\/fs-uae\/tree\/lua<\/a><\/p>\n

I also submitted the patch as a pull request<\/a> for the main line FS-UAE \u00c2\u00a0and hope that Frode will like this feature and include it \ud83d\ude42<\/p>\n

Clone this branch and start the compilation with the following options:<\/p>\n

$ .\/bootstrap\r\n$ mkdir build\r\n$ cd build\r\n$ ..\/configure --enable-lua<\/pre>\n
Now you can compile it:<\/p>\n
$ make\r\n$ (cd dist\/macosx && make) \u00c2\u00a0# only on Mac OS X<\/pre>\n
This results in a new FS-UAE binary with lua shell support.<\/p>\n
2. Configure and First Start<\/h3>\n
You have to enable the lua shell in order to use it.<\/p>\n
Either add an option to one of your\u00c2\u00a0.fs-uae<\/strong> config files:<\/p>\n
lua_shell = 1<\/pre>\n
or give the option on the command line:<\/p>\n
fs-uae ... --lua_shell=1<\/pre>\n
The lua shell opens a TCP\/IP socket on localhost port 6800<\/strong> and waits for incoming client connects e.g. via telnet or putty.<\/p>\n
You can use the following options to change these settings:<\/p>\n
lua_shell_addr = \"localhost\"\r\nlua_shell_port = 6800<\/pre>\n
Now launch FS-UAE with the lua shell option enabled and have a look at the log files. They usually reside in Documents\/FS-UAE\/Cache\/Logs\/fs-uae.log.txt.<\/em><\/p>\n
There watch out for messages starting with lua-shell:<\/p>\n
$ grep lua-shell ~\/Documents\/FS-UAE\/Cache\/Logs\/fs-uae.log.txt\r\nlua-shell: addr=127.0.0.1, port=6800\r\nlua-shell: +listener: 20\r\nlua-shell: -listener\r\nlua-shell: stopping done...<\/pre>\n
If you see these messages you should be able to connect while the emulator is running:<\/p>\n
$ telnet 127.0.0.1 6800\r\nTrying 127.0.0.1...\r\nConnected to localhost.\r\nEscape character is '^]'.\r\nFS-UAE 2.5.29dev Lua 5.2\r\n><\/pre>\n
Ok. Now lets see what you can do in the shell…<\/p>\n
3. Using the shell<\/h3>\n
The lua shell is very similar to the interactive lua interpreter that is shipped with lots of lua distributions (see doc<\/a>). You can enter a valid lua statement that is then evaluated in the current lua state:<\/p>\n
> print \"hello, world!\"\r\nhello, world!<\/pre>\n
Note, that the print command is redirected to your shell. Any return value is not printed automatically, you need to prepend a\u00c2\u00a0=<\/strong>\u00c2\u00a0(or return) before you can enter an expression:<\/p>\n
> =2+3\r\n5<\/pre>\n
Next to most libs that lua already ships the lua shell in FS-UAE also registers special emulator commands for you (see next section for details):<\/p>\n
> =fsuae.floppy.get_num_drives()\r\n1<\/pre>\n
This returns the number of virtual floppy drives that are currently emulated.<\/p>\n
If you want to quit the shell then enter the quit() command:<\/p>\n
> quit()<\/pre>\n
You can also simply disconnect the connection by closing with telnet or putty…<\/p>\n
3. FS-UAE Lua commands<\/h3>\n
Currently, the following modules are defined with commands:<\/p>\n