Date: Mon, 27 Feb 2017 07:26:09 -0800 From: Allan Jude <allanjude@FreeBSD.org> To: freebsd-hackers@freebsd.org, Saurav Sachidanand <sauravsachidanand@gmail.com>, soc-admins@freebsd.org Subject: Re: [GSoC 2017] Original proposal: Port kernel Lua to FreeBSD Message-ID: <244231A2-EB18-4E58-A2B2-927F55D54950@FreeBSD.org> In-Reply-To: <CACKq%2BiX_V2MY9sNf-buEOO1S87dbhDv%2BPGbUEqRUVkvzz3pdvw@mail.gmail.com> References: <CACKq%2BiX_V2MY9sNf-buEOO1S87dbhDv%2BPGbUEqRUVkvzz3pdvw@mail.gmail.com>
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On February 27, 2017 5:28:41 AM PST, Saurav Sachidanand <sauravsachidanand@gmail.com> wrote: >Hello FreeBSD community, > >I'm >​ Saurav Sachidanand, and I'm​ > a CS sophomore studying in India >​. >I have an interest in operating systems development and wish to >contribute >to the FreeBSD community. I'm proficient with C and have some >experience in >kernel programming. Hence, I'd like to propose an original project for >GSoC >2017 that I feel would benefit this community. > >In past years, the Lua interpreter was ported to run inside the Linux >and >NetBSD kernel [1]. Lua was chosen because it's interpreter is very >small (~240 >KB) compared to that of Python or Ruby, it's MIT licensed, and is >almost >freestanding. A working demonstration of it is a packet filtering >algorithm >written entirely in kernel Lua [2]. > >Specifically, my proposal would be to port the following that are >currently >written for NetBSD: >- the modified Lua VM source code with _KERNEL preprocessor directives >to >exclude user-space functionality like floating point, the io and os >module >in the standard library, etc. [3] >- the kernel module device driver for /dev/lua, to which Lua scripts >are >fed to be executed [4], [5] >- the luactl user-space program to control the Lua device and a couple >of >sysctl variables which serve similar purpose [6], [7] > >And then: >- run the Lua test suite targeting whatever we support in the kernel to >make sure it works [8] >- and write Lua bindings to the kernel interfaces that would interest >the >FreeBSD community > >Since NetBSD and FreeBSD have similar kernel interfaces (mutexes, >linked >lists, device switch interface), the porting shouldn't involve too much >code refactoring. Also, this would all be an experiment in that we >don't >fully know what the real world use cases might be, but it would attract >more people to writing kernel code who otherwise wouldn't because of >having >to do everything in C. And it would be interesting to carry out it out >in >FreeBSD as well since it has a larger community than NetBSD. > >I humbly request anyone who is interested in this project to be my >potential mentor(s) for GSoC. > >More slides on kernel Lua in NetBSD - [9], [10]. > >Thanks, >Saurav > >[1] - http://www.netbsd.org/~lneto/dls14.pdf >[2] - https://www.netbsd.org/~lneto/eurobsdcon14.pdf >[3] - https://github.com/jsonn/src/tree/trunk/external/mit/lua/dist/src >[4] - >https://github.com/IIJ-NetBSD/netbsd-src/tree/master/sys/modules/lua >[5] - >https://github.com/IIJ-NetBSD/netbsd-src/tree/master/sys/modules/luasystm >[6] - https://github.com/IIJ-NetBSD/netbsd-src/tree/master/sbin/luactl >[7] - http://netbsd.gw.com/cgi-bin/man-cgi?lua+4+NetBSD-current >[8] - http://www.lua.org/tests/ >[9] - >https://www.netbsd.org/gallery/presentations/mbalmer/fosdem2012/kernel_mode_lua.pdf >[10] - https://www.lua.org/wshop13/Cormack.pdf >_______________________________________________ >freebsd-hackers@freebsd.org mailing list >https://lists.freebsd.org/mailman/listinfo/freebsd-hackers >To unsubscribe, send any mail to >"freebsd-hackers-unsubscribe@freebsd.org" This may be quite a nice thing to have. Another upcoming use for LUA in the kernel is ZFS Channel Programs. These allow a number of ZFS operations to be completed as a single atomic transaction. I would hope we could structure this in such a way as to not end up with two copies of Lua in the kernel. -- Allan Jude
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