shelter ideas

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liquidex 2023-11-20 12:27:38 +01:00
parent 7b525adf42
commit e944e8c34b
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% id = "programming/projects/stitchkit"
content.link = "programming/projects/stitchkit"
+ ### Stitchkit
A Hat in Time mod stitching toolkit
% id = "programming/projects/muscript"
content.link = "programming/projects/muscript"
+ ### MuScript
UnrealScript compiler, part of stitchkit
% id = "programming/projects/yarnbox"
content.link = "programming/projects/yarnbox"
+ ### Yarnbox
A Hat in Time bytecode injection mod loader
% id = "programming/projects/shelter"
content.link = "programming/projects/shelter"
+ ### shelter
ideas for an operating system; not actually implemented

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% id = "01HFP3E77CH0NDBBDCGFSNCS36"
+ _shelter_ is my design for a potential operating system and runtime which foregoes the entire
legacy of today's systems
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+ compatibility is not a design goal for shelter, the idea is that we build the entire universe
from scratch
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- therefore shelter is not compatible with UNIX, POSIX, or Windows
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- it should be possible to build compatibility layers, but they probably won't be part of
the project
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+ the design goal is to build a **secure operating system you can trust**
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- gone will be the days where you download an executable from the Internet and have no idea
what harm it can do to your system
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- security is to be achieved while keeping the system fundamentally simple. the less code
you have to inspect, the better
% id = "01HFP3E77CGBD4ZQ2JN4Z761VE"
+ **NOTE:** at this point shelter is nothing more than an incomplete design. OS development is
something I wanna get into but haven't enough time to research everything as of now, therefore
I'm jotting down my ideas here
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- but if all goes well you'll be able to run it one day
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+ ### design
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+ execution environment
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+ the execution environment of shelter is one big JIT compiler.
code is portable between CPU architectures and exchanged via a compact intermediate
representation (IR), which is then compiled to machine code when installed into the system
% id = "01HFP3E77CBJ6SRFW34HW7BE4V"
- compilers which emit this IR must not perform aggressive inlining. this is
important for the OS's [function database][branch:01HFP3E77CSZCHA4TS0R7VNT9N] to
work correctly and be able to deduplicate functions aggresively.
instead, inlining is done by the JIT upon compilation (or maybe even based on profiling)
% id = "01HFP7K50TV3FQ5PYXA5S6P9FT"
- note that although there is a JIT, there is no garbage collection. memory is allocated
and freed manually by running programs
% id = "01HFP7K50TBSSHSJAYVE7SY5T7"
- the environment supports algebraic effects, which are used to annotate functions which may
perform I/O, access the network, and perform mischief using them.
% id = "01HFP3E77CSZCHA4TS0R7VNT9N"
+ executable code
% id = "01HFP3E77CDB6Z6YKPJ1PJS0KC"
- this is probably the most exciting part of shelter: how executable code is not stored
within `.exe` and `.dll` files, but rather in a database managed by the OS
% id = "01HFP3E77CNXNFQBZWT3JD47ZD"
- the database is basically just this:
```rust
struct CodeDatabase {
types: HashMap<Hash<Type>, Type>,
functions: HashMap<Hash<Function>, Function>,
}
```
% id = "01HFP3E77CRP3HFGTRYFJ2HMWQ"
- `Hash<T>` is the hash of the value `T`.
% id = "01HFP3E77CZJFH9NRMM8SJ96HD"
- `Hash<T>` is large enough to practically prevent any and all collisions (is 256 bits with a cryptographically secure hash function enough?)
% id = "01HFP3E77C6ZYGDFKBVXZYMME9"
+ functions in the database are fully anonymous; function names can be given via
separate debug info that can be attached to a running program to provide stack traces
% id = "01HFP3E77CM03HZQ20VZ5PEY2E"
- this debug info correlates a function's properties with source code and is
completely optional
% id = "01HFP3E77CKS7CFPFCZJEDJ5G8"
- functions from within the database can be aliased in the filesystem. you can create
a file which executes a function annotated as a valid entrypoint
% id = "01HFP7K50T39EG59CXFJ76E1GT"
+ function metadata includes reflection data - argument/return types, generics (so that
monomorphization is performed on-demand by the JIT to save disk space), and annotations
(so that the OS can know eg. which functions are valid program entry points)
% id = "01HFP7K50TPHWNZC1AK9ZG9AKQ"
- this reflection data can be queried by anyone in userspace
% id = "01HFP7K50TRDETH3JKNYJPQ6QK"
- it can be used eg. to implement a shell, which executes named functions, such as `ls` here:
```
@os.entrypoint
fun ls(
caps: (working_directory: shell.WorkingDirectory(:read)),
args: (compact: shell.Flag(short: "l")),
): Result(())
:: os.stdio.Write + os.Filesystem =
caps.working_directory.path
| fs.walk fun (entry) = {
if args.compact.is_set then {
print("\{entry | fs.dirent.path? | path.filename}")
} else {
print("\{entry.kind}\t\{entry | fs.dirent.path? | path.filename}")
}
}
```
% id = "01HFP3E77CGCWJKS84AJJDZJ71"
+ capability based security
% id = "01HFP7K50TK8CVWP87J2BNBXVW"
- functions can only do what they say they do, and access what they say they access
% id = "01HFP7K50TDBR6JM70Q4RSX52A"
+ the first of these is achieved through an effect system within the language runtime
% id = "01HFP7K50TA32V17YTEHY1SNTN"
- a function can only write to stdout if it declares it performs the `os.stdio.Write` effect
% id = "01HFP7K50TTGW5SQXFVDJBY8TG"
+ the second of these is achieved through explicitly passing capabilities as function arguments
% id = "01HFP7K50TAQ44W2XCKE8Q4RDS"
- you do not have access to a directory if you're not explicitly given
a `fs.Directory` value
% id = "01HFP7K50TJ692F8BTKH3RVXMV"
- moreso, if you need to read or write directory values, the directory needs to
explicitly be locked (using an rwlock) to help prevent TOCTOU race conditions
% id = "01HFP7K50TE1KYTC5RZ7P49FGW"
- not to say such race conditions will be completely impossible, but they
will be much harder to run into on accident
% id = "01HFP7K50T23DK68VYAQTE24Z0"
- it's also impossible to fabricate capabilities because low-level memory access can
only be performed explicitly through byte slices, and only types whose definition is
public can be cast into byte slices
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+ package management
% id = "01HFP7K50TF07N4W61C8GC2GVZ"
- because functions are identifiable by their hash, it's easy to implement a decentralized
function registry
% id = "01HFP7K50TKFBQ6G0GXE8J4H3Y"
- the OS can store a list of mirrors and request functions from them as needed
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- if one mirror doesn't have a function, the system can request it from another mirror
% id = "01HFP7K50T35YCZEWST3ZV4M6Q"
- if no mirrors have a function, tell the user
% id = "01HFP7K50TSTWWCWRPG5A3TCXJ"
- functions downloaded from the Internet can be validated by checking that the hash of
the received function matches that of the requested function
% id = "01HFP7K50THRGCDEYKB4SYWQFD"
- the bytecode's structure should be validated at this point as well

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% id = "01HA4NZ9DC15Y3EQ0E3A4EKEJ2"
- [repo][def:abit/repo]
% id = "01HA4NZ9DCAST8G6262A6YQA1D"
- dynamic bytecode patcher - it injects into your game, fiddles with the bytecode as it loads, and modifies existing code that way
% id = "01HA4NZ9DCMH8A92GF8V3VEE93"
- part of the ABiT mod loader project
% id = "01HA4NZ9DCZH4DPQWB4QVKM7N9"
- which is now dead because Gears for Breakfast took away the game's debug symbols :cry:
% id = "01HA4NZ9DCAST8G6262A6YQA1D"
- dynamic bytecode patcher - it injects into your game, fiddles with the bytecode as it loads, and modifies existing code that way