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#[cfg(feature = "gpu")]
use bytemuck::{Pod, Zeroable};
use crate::error::{Error, Result};
/// VM opcode.
#[repr(u32)]
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum Opcode {
/// Push `true` onto the evaluation stack.
PushTrue = 1,
/// Push `false` onto the evaluation stack.
PushFalse = 2,
/// Push whether the current string matched.
PushStringMatched = 3,
/// Push the match count for the current string.
PushStringCount = 4,
/// Push the offset of the current string match.
PushStringOffset = 5,
/// Push the length of the current string match.
PushStringLength = 6,
/// Push the file size in bytes.
PushFileSize = 7,
/// Push the number of rule entries.
PushEntryCount = 8,
/// Push an immediate operand value.
PushImmediate = 9,
/// Push the total number of strings.
PushNumStrings = 10,
/// Boolean AND of the top two stack values.
And = 11,
/// Boolean OR of the top two stack values.
Or = 12,
/// Boolean NOT of the top stack value.
Not = 13,
/// Equality comparison.
Eq = 14,
/// Inequality comparison.
Neq = 15,
/// Less-than comparison.
Lt = 16,
/// Greater-than comparison.
Gt = 17,
/// Less-than-or-equal comparison.
Lte = 18,
/// Greater-than-or-equal comparison.
Gte = 19,
/// Arithmetic addition.
Add = 20,
/// Arithmetic subtraction.
Sub = 21,
/// Count the number of matching items.
CountOf = 22,
/// True when all items match.
AllOf = 23,
/// True when any item matches.
AnyOf = 24,
/// Check whether a string exists at a specific offset.
StringAt = 25,
/// Check whether a string exists in a range.
StringIn = 26,
/// Begin a `for any` iteration block.
ForAny = 27,
/// Begin a `for all` iteration block.
ForAll = 28,
/// End the current `for` block.
EndFor = 29,
/// Stop execution.
Halt = 30,
/// Arithmetic multiplication.
Mul = 31,
/// Arithmetic division.
Div = 32,
/// Arithmetic modulo.
Mod = 33,
/// Bitwise AND.
BitAnd = 34,
/// Bitwise OR.
BitOr = 35,
/// Bitwise XOR.
BitXor = 36,
/// Bitwise shift left.
Shl = 37,
/// Bitwise shift right.
Shr = 38,
/// Read a little-endian integer at the given offset.
ReadIntAt = 39,
/// Begin a `for N` iteration block.
ForN = 40,
/// Push the file entropy bucket.
PushEntropy = 41,
/// Push whether the file is a PE.
PushIsPe = 42,
/// Push whether the PE is a DLL.
PushIsDll = 43,
/// Push the number of PE sections.
PushNumSections = 44,
/// Push the number of PE imports.
PushNumImports = 45,
/// Push the PE entry point RVA.
PushEntryPoint = 46,
/// Push whether the PE has a signature.
PushHasSignature = 47,
/// Push the first four bytes of the file as a `u32`.
PushMagicU32 = 48,
/// Push whether the PE is 64-bit.
PushIs64bit = 49,
/// Pop `pattern_a`, `pattern_b`; push `1` when the first match of `pattern_a`
/// appears before the first match of `pattern_b`, otherwise `0`.
MatchOrder = 50,
/// Pop `pattern_a`, `pattern_b`; push the smallest byte gap between any
/// cached matches of the two patterns, or `0` when either pattern is absent.
MatchDistance = 51,
/// Pop `pattern_a`, `pattern_b`, `pattern_c`; push `1` when any match of
/// `pattern_c` starts between the first matches of `pattern_a` and `pattern_b`.
MatchBetween = 52,
/// Pop `pattern_a`, `pattern_b`; push `1` when any cached matches of both
/// patterns share the same approximate brace nesting level.
MatchSameScope = 53,
/// Pop `pattern_a`, `pattern_b`, `max_distance`; push `1` when any match of
/// `pattern_b` starts within `max_distance` bytes after a match of `pattern_a`.
MatchAfter = 54,
/// Pop `pattern_id`; push the entropy bucket (`0..=255`) of that pattern's
/// first cached matched region, or `0` when no cached region exists.
MatchedRegionEntropy = 55,
/// Pop `pattern_id`, `index`; push the length of the indexed cached match,
/// mirroring [`Opcode::PushStringLength`] with explicit stack operands.
MatchedRegionLength = 56,
/// Pop `pattern_id`, `window_size`; push the largest number of cached matches
/// whose start offsets fall within any `window_size`-byte window.
PatternDensity = 57,
/// Push the number of distinct global pattern ids that matched this file.
UniquePatternCount = 58,
/// Push the total number of matches observed for this file across all patterns.
TotalMatchCount = 59,
/// Pop `offset`; push the byte at that file offset, or `0` when out of bounds.
ReadByteAt = 60,
/// Pop `offset`, `len`, `expected_hash`; push `1` when the FNV-1a hash of the
/// bytes at `offset..offset+len` equals `expected_hash`, otherwise `0`.
ReadBytesEqual = 61,
/// Pop `offset`; alias for [`Opcode::ReadByteAt`].
ByteAt = 62,
/// Pop `value`, `key`; push `value ^ key`.
XorByte = 63,
}
impl Opcode {
/// Decode an opcode from its serialized `u32` form.
///
/// # Examples
/// ```
/// use rulefire::Opcode;
///
/// assert_eq!(Opcode::from_u32(1).unwrap(), Opcode::PushTrue);
/// ```
pub fn from_u32(value: u32) -> Result<Self> {
const ALL: &[(u32, Opcode)] = &[
(1, Opcode::PushTrue), (2, Opcode::PushFalse), (3, Opcode::PushStringMatched),
(4, Opcode::PushStringCount), (5, Opcode::PushStringOffset),
(6, Opcode::PushStringLength), (7, Opcode::PushFileSize), (8, Opcode::PushEntryCount),
(9, Opcode::PushImmediate), (10, Opcode::PushNumStrings), (11, Opcode::And),
(12, Opcode::Or), (13, Opcode::Not), (14, Opcode::Eq), (15, Opcode::Neq),
(16, Opcode::Lt), (17, Opcode::Gt), (18, Opcode::Lte), (19, Opcode::Gte),
(20, Opcode::Add), (21, Opcode::Sub), (22, Opcode::CountOf), (23, Opcode::AllOf),
(24, Opcode::AnyOf), (25, Opcode::StringAt), (26, Opcode::StringIn),
(27, Opcode::ForAny), (28, Opcode::ForAll), (29, Opcode::EndFor), (30, Opcode::Halt),
(31, Opcode::Mul), (32, Opcode::Div), (33, Opcode::Mod), (34, Opcode::BitAnd),
(35, Opcode::BitOr), (36, Opcode::BitXor), (37, Opcode::Shl), (38, Opcode::Shr),
(39, Opcode::ReadIntAt), (40, Opcode::ForN), (41, Opcode::PushEntropy),
(42, Opcode::PushIsPe), (43, Opcode::PushIsDll), (44, Opcode::PushNumSections),
(45, Opcode::PushNumImports), (46, Opcode::PushEntryPoint),
(47, Opcode::PushHasSignature), (48, Opcode::PushMagicU32),
(49, Opcode::PushIs64bit), (50, Opcode::MatchOrder),
(51, Opcode::MatchDistance), (52, Opcode::MatchBetween),
(53, Opcode::MatchSameScope), (54, Opcode::MatchAfter),
(55, Opcode::MatchedRegionEntropy), (56, Opcode::MatchedRegionLength),
(57, Opcode::PatternDensity), (58, Opcode::UniquePatternCount),
(59, Opcode::TotalMatchCount), (60, Opcode::ReadByteAt),
(61, Opcode::ReadBytesEqual), (62, Opcode::ByteAt), (63, Opcode::XorByte),
];
ALL.iter()
.find_map(|(raw, opcode)| (*raw == value).then_some(*opcode))
.ok_or_else(|| Error::BytecodeValidation {
message: format!("unknown opcode {value}"),
})
}
}
/// Single 8-byte VM instruction.
#[repr(C)]
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
#[cfg_attr(feature = "gpu", derive(Pod, Zeroable))]
pub struct Instruction {
/// Opcode as `u32`.
pub opcode: u32,
/// Instruction operand.
pub operand: u32,
}
impl Instruction {
/// Create an instruction.
///
/// # Examples
/// ```
/// use rulefire::{Instruction, Opcode};
///
/// let instruction = Instruction::new(Opcode::PushImmediate, 7);
/// assert_eq!(instruction.operand, 7);
/// ```
pub const fn new(opcode: Opcode, operand: u32) -> Self {
Self {
opcode: opcode as u32,
operand,
}
}
/// Parse the opcode kind for this instruction.
///
/// # Examples
/// ```
/// use rulefire::{Instruction, Opcode};
///
/// let instruction = Instruction::new(Opcode::PushTrue, 0);
/// assert_eq!(instruction.kind().unwrap(), Opcode::PushTrue);
/// ```
pub fn kind(self) -> Result<Opcode> {
Opcode::from_u32(self.opcode)
}
}