wasmer_types/
trapcode.rs

1// This file contains code from external sources.
2// Attributions: https://github.com/wasmerio/wasmer/blob/main/docs/ATTRIBUTIONS.md
3
4//! Trap codes describing the reason for a trap.
5
6use core::fmt::{self, Display, Formatter};
7use core::str::FromStr;
8use rkyv::{Archive, Deserialize as RkyvDeserialize, Serialize as RkyvSerialize};
9#[cfg(feature = "enable-serde")]
10use serde::{Deserialize, Serialize};
11use thiserror::Error;
12
13/// A trap code describing the reason for a trap.
14///
15/// All trap instructions have an explicit trap code.
16#[derive(
17    Clone, Copy, PartialEq, Eq, Debug, Hash, Error, RkyvSerialize, RkyvDeserialize, Archive,
18)]
19#[cfg_attr(feature = "enable-serde", derive(Serialize, Deserialize))]
20#[cfg_attr(feature = "artifact-size", derive(loupe::MemoryUsage))]
21#[rkyv(derive(Debug), compare(PartialEq))]
22#[repr(u32)]
23pub enum TrapCode {
24    /// The current stack space was exhausted.
25    ///
26    /// On some platforms, a stack overflow may also be indicated by a segmentation fault from the
27    /// stack guard page.
28    StackOverflow = 0,
29
30    /// A `heap_addr` instruction detected an out-of-bounds error.
31    ///
32    /// Note that not all out-of-bounds heap accesses are reported this way;
33    /// some are detected by a segmentation fault on the heap unmapped or
34    /// offset-guard pages.
35    HeapAccessOutOfBounds = 1,
36
37    /// A `heap_addr` instruction was misaligned.
38    HeapMisaligned = 2,
39
40    /// A `table_addr` instruction detected an out-of-bounds error.
41    TableAccessOutOfBounds = 3,
42
43    /// Indirect call to a null table entry.
44    IndirectCallToNull = 4,
45
46    /// Signature mismatch on indirect call.
47    BadSignature = 5,
48
49    /// An integer arithmetic operation caused an overflow.
50    IntegerOverflow = 6,
51
52    /// An integer division by zero.
53    IntegerDivisionByZero = 7,
54
55    /// Failed float-to-int conversion.
56    BadConversionToInteger = 8,
57
58    /// Code that was supposed to have been unreachable was reached.
59    UnreachableCodeReached = 9,
60
61    /// An atomic memory access was attempted with an unaligned pointer.
62    UnalignedAtomic = 10,
63}
64
65impl TrapCode {
66    /// Gets the message for this trap code
67    pub fn message(&self) -> &str {
68        match self {
69            Self::StackOverflow => "call stack exhausted",
70            Self::HeapAccessOutOfBounds => "out of bounds memory access",
71            Self::HeapMisaligned => "misaligned heap",
72            Self::TableAccessOutOfBounds => "undefined element: out of bounds table access",
73            Self::IndirectCallToNull => "uninitialized element",
74            Self::BadSignature => "indirect call type mismatch",
75            Self::IntegerOverflow => "integer overflow",
76            Self::IntegerDivisionByZero => "integer divide by zero",
77            Self::BadConversionToInteger => "invalid conversion to integer",
78            Self::UnreachableCodeReached => "unreachable",
79            Self::UnalignedAtomic => "unaligned atomic access",
80        }
81    }
82}
83
84impl Display for TrapCode {
85    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
86        let identifier = match *self {
87            Self::StackOverflow => "stk_ovf",
88            Self::HeapAccessOutOfBounds => "heap_get_oob",
89            Self::HeapMisaligned => "heap_misaligned",
90            Self::TableAccessOutOfBounds => "table_get_oob",
91            Self::IndirectCallToNull => "icall_null",
92            Self::BadSignature => "bad_sig",
93            Self::IntegerOverflow => "int_ovf",
94            Self::IntegerDivisionByZero => "int_divz",
95            Self::BadConversionToInteger => "bad_toint",
96            Self::UnreachableCodeReached => "unreachable",
97            Self::UnalignedAtomic => "unalign_atom",
98        };
99        f.write_str(identifier)
100    }
101}
102
103impl FromStr for TrapCode {
104    type Err = ();
105
106    fn from_str(s: &str) -> Result<Self, Self::Err> {
107        match s {
108            "stk_ovf" => Ok(Self::StackOverflow),
109            "heap_get_oob" => Ok(Self::HeapAccessOutOfBounds),
110            "heap_misaligned" => Ok(Self::HeapMisaligned),
111            "table_get_oob" => Ok(Self::TableAccessOutOfBounds),
112            "icall_null" => Ok(Self::IndirectCallToNull),
113            "bad_sig" => Ok(Self::BadSignature),
114            "int_ovf" => Ok(Self::IntegerOverflow),
115            "int_divz" => Ok(Self::IntegerDivisionByZero),
116            "bad_toint" => Ok(Self::BadConversionToInteger),
117            "unreachable" => Ok(Self::UnreachableCodeReached),
118            "unalign_atom" => Ok(Self::UnalignedAtomic),
119            _ => Err(()),
120        }
121    }
122}
123
124// TODO: OnCalledAction is needed for asyncify. It will be refactored with https://github.com/wasmerio/wasmer/issues/3451
125/// After the stack is unwound via asyncify what
126/// should the call loop do next
127#[derive(Debug)]
128pub enum OnCalledAction {
129    /// Will call the function again
130    InvokeAgain,
131    /// Will return the result of the invocation
132    Finish,
133    /// Traps with an error
134    Trap(Box<dyn std::error::Error + Send + Sync>),
135}
136
137#[cfg(test)]
138mod tests {
139    use super::*;
140
141    // Everything but user-defined codes.
142    const CODES: [TrapCode; 11] = [
143        TrapCode::StackOverflow,
144        TrapCode::HeapAccessOutOfBounds,
145        TrapCode::HeapMisaligned,
146        TrapCode::TableAccessOutOfBounds,
147        TrapCode::IndirectCallToNull,
148        TrapCode::BadSignature,
149        TrapCode::IntegerOverflow,
150        TrapCode::IntegerDivisionByZero,
151        TrapCode::BadConversionToInteger,
152        TrapCode::UnreachableCodeReached,
153        TrapCode::UnalignedAtomic,
154    ];
155
156    #[test]
157    fn display() {
158        for r in &CODES {
159            let tc = *r;
160            assert_eq!(tc.to_string().parse(), Ok(tc));
161        }
162        assert_eq!("bogus".parse::<TrapCode>(), Err(()));
163
164        // assert_eq!(TrapCode::User(17).to_string(), "user17");
165        // assert_eq!("user22".parse(), Ok(TrapCode::User(22)));
166        assert_eq!("user".parse::<TrapCode>(), Err(()));
167        assert_eq!("user-1".parse::<TrapCode>(), Err(()));
168        assert_eq!("users".parse::<TrapCode>(), Err(()));
169    }
170}
wasmer_types/trapcode.rs

wasmer_types/
trapcode.rs
