forked from AbleOS/ableos
65 lines
2.2 KiB
Rust
65 lines
2.2 KiB
Rust
//! Validate if program is sound to execute
|
|
|
|
/// Program validation error kind
|
|
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
|
|
pub enum ErrorKind {
|
|
/// Unknown opcode
|
|
InvalidInstruction,
|
|
/// VM doesn't implement this valid opcode
|
|
Unimplemented,
|
|
/// Attempted to copy over register boundary
|
|
RegisterArrayOverflow,
|
|
}
|
|
|
|
/// Error
|
|
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
|
|
pub struct Error {
|
|
/// Kind
|
|
pub kind: ErrorKind,
|
|
/// Location in bytecode
|
|
pub index: usize,
|
|
}
|
|
|
|
/// Perform bytecode validation. If it passes, the program should be
|
|
/// sound to execute.
|
|
pub fn validate(mut program: &[u8]) -> Result<(), Error> {
|
|
use hbbytecode::opcode::*;
|
|
|
|
let start = program;
|
|
loop {
|
|
// Match on instruction types and perform necessary checks
|
|
program = match program {
|
|
[] => return Ok(()),
|
|
[LD..=ST, reg, _, _, _, _, _, _, _, _, _, count, ..]
|
|
if usize::from(*reg) * 8 + usize::from(*count) > 2048 =>
|
|
{
|
|
return Err(Error {
|
|
kind: ErrorKind::RegisterArrayOverflow,
|
|
index: (program.as_ptr() as usize) - (start.as_ptr() as usize),
|
|
})
|
|
}
|
|
[BRC, src, dst, count, ..]
|
|
if src.checked_add(*count).is_none() || dst.checked_add(*count).is_none() =>
|
|
{
|
|
return Err(Error {
|
|
kind: ErrorKind::RegisterArrayOverflow,
|
|
index: (program.as_ptr() as usize) - (start.as_ptr() as usize),
|
|
})
|
|
}
|
|
[NOP | ECALL, rest @ ..]
|
|
| [DIR | DIRF, _, _, _, _, rest @ ..]
|
|
| [ADD..=CMPU | BRC | ADDF..=MULF, _, _, _, rest @ ..]
|
|
| [NEG..=NOT | CP..=SWA, _, _, rest @ ..]
|
|
| [LI | JMP, _, _, _, _, _, _, _, _, _, rest @ ..]
|
|
| [ADDI..=CMPUI | BMC | JEQ..=JGTU | ADDFI..=MULFI, _, _, _, _, _, _, _, _, _, _, rest @ ..]
|
|
| [LD..=ST, _, _, _, _, _, _, _, _, _, _, _, _, rest @ ..] => rest,
|
|
_ => {
|
|
return Err(Error {
|
|
kind: ErrorKind::InvalidInstruction,
|
|
index: (program.as_ptr() as usize) - (start.as_ptr() as usize),
|
|
})
|
|
}
|
|
}
|
|
}
|
|
}
|