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NetBSD To Support Kernel Development In Lua Scripting
An anonymous reader writes "NetBSD 7.0 will support the Lua scripting language within its kernel for developing drivers and new sub-systems. A Lua scripting interpreter is being added to the NetBSD kernel along with a kernel API so developers can use this scripting language rather than C for developing new BSD kernel components. Expressed reasons for supporting a scripting language in a kernel were rapid application development, better configuration, and "modifying software written in C is hard for users." In a presentation it was said that Lua in the kernel will let users explore their system in an easy way."
This is a good thing, and it's long overdue. Linux should do the same.
It's actually pretty easy to get Lua running in the kernel and call kernel APIs; but to make it really useful, it needs additional kernel hooks and callbacks, and that requires cooperation from the core kernel developers.
I honestly think that this is a great idea. It's a novel approach to extending a kernel, especially considering NetBSD doesn't have that big of a market share and expressly focusses on supporting as many platforms as possible. Prototyping new features or certain drivers in a portable scripting language may give them a leg up in the functionality aspect of the race.
Also, LUA is super fast, small, easy to learn, concise and the C API/embedding it is straight forward.
You may knock it all you want, "because kernel land is C land", but after all bias being said and flamed, this may turn out to be a really fun, interesting and possibly very useful idea.
It seems crazy, but this may not be as braindead as it seems. For instance, a keyboard driver. You just need a read key state->have a look up table to the keycodes function, then pass it on. This is redundant, few lines of code with very little difference between most other drivers. You may not want to write your graphic drivers in it, but not every driver needs bare metal functionality
"When life gives you lemons, don't make lemonade. Make life take the lemons back!" -- Cave Johnson
Interesting - failure of user space in this way is exactly why we have zero-days.
I would like to see this happen - but several things make it improbable:
1. Von Neuman architecture. As long as data and instructions exist in the same space - poorly written apps will allow abuse of it.
2. Complexity of current software. The more complex the software, the more likely a bug will exist in it that allows #1. Given how programmers stitch together preexisting modules without understanding what is being done on the underlying system - I only expect that to continue expanding.
It should be instructive that Java was supposed to be that sandboxed layer...and it has so many zero-days it looks like swiss cheese.
Now - how would we avoid that and make an unhackable userspace?
Lodragan Draoidh
The more you explain it, the more I don't understand it. - Mark Twain
i thought *users* had no business writing device drivers?
My non programmer wife wrote a custom device driver in AppleScript, not even knowing what a device driver is. Those sorts of languages can be amazing empowering to end users, and yes there are reasons that end users might want a custom device driver if it is easy enough to accomplish. Though this makes more sense for OSX than NetBSD, I doubt there are many if any non programmers who use NetBSD.
I had to write a custom device driver for Windows once to get something more like a Unix ethernet driver i.e. bypass some normally quite excellent parts of the Windows networking stack. I was doing software not hardware so I guess I'd consider myself an end user. And that was a pain in the ass.
I don't know how much Unix/BSD/Linus code you have read or written, but I have been developing core code, Scheduler, MM and Drivers since 1980 and this is a great idea, long overdue.
The Abstractions are now well understood and most code dos't need to be quick, but safe, putting PRE in kernels will clean up acres of cockamamie code now written in C, most of which just runs at boot time and is then freed. ... there are exceptions, you cant't have the garbage collector running whenever it likes, eg in the middle of an interrupt routine, but managed memory, not C, C++ scoping is the way to stop slow memory leaks.
Put simply you are an idiot and dont know what you are talking about.
MFG, omb
It is potentially stupid, but the reason is much more subtle than most people realize. For all its limitations and headache, C does have one key feature that makes it suitable for kernel programming where most other languages are not: the concept of well-defined storage durations and reserving storage for an object. I really question whether Lua code running as part of the kernel can be made robust under out-of-memory conditions which a kernel must be able to survive.