I wanted a tiny scriptable meltdown proof way to run userspace programs
and visualize how program execution impacts memory. It helps to explain
how things like Actually Portable Executable works. It can show you how
the GCC generated code is going about manipulating matrices and more. I
didn't feel fully comfortable with Qemu and Bochs because I'm not smart
enough to understand them. I wanted something like gVisor but with much
stronger levels of assurances. I wanted a single binary that'll run, on
all major operating systems with an embedded GPL barrier ZIP filesystem
that is tiny enough to transpile to JavaScript and run in browsers too.
https://justine.storage.googleapis.com/emulator625.mp4
One of the benefits of implementing system call support from scratch is
that we're able to have embedded zip filesystem support which trickles
into libraries such as stdio, without unportable symbolic interposition.
It's also be great if we could say open("gs://bucket/object", O_RDONLY)
for seamless GCS, similar to Java NIO, but abstracted by the C library.
The binary system interfaces designed at Bell Labs were what helped our
friends like Linus Torvalds become successful. It's why Torvalds always
respected syscall abi and made every effort to not break the userspace.
Sadly OpenBSD developer Theo de Raadt thinks respecting Bell interfaces
is a risk for security and conjured up the Return Oriented Programming
bogeyman to justify his policies, per https://lwn.net/Articles/806776/
See libc/nexgen32e/gc.S where we use ROP concepts for garbage collection
in C due to our belief that powerful programming techniques can be good.
See https://opensource.googleblog.com/2017/03/operation-rosehub.html for
an example of something similar to rop but potentially more of a concern
Justine Tunney
