1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
|
// References:
// https://github.com/rust-lang/rust/blob/c4be230b4a30eb74e3a3908455731ebc2f731d3d/library/panic_unwind/src/gcc.rs
// https://github.com/rust-lang/rust/blob/c4be230b4a30eb74e3a3908455731ebc2f731d3d/library/panic_unwind/src/dwarf/eh.rs
// https://docs.rs/gimli/0.25.0/src/gimli/read/cfi.rs.html
use core::mem;
use gimli::{constants, NativeEndian};
use gimli::{EndianSlice, Error, Pointer, Reader};
use crate::abi::*;
use crate::arch::*;
use crate::util::*;
#[derive(Debug)]
enum EHAction {
None,
Cleanup(usize),
Catch(usize),
}
fn parse_pointer_encoding(input: &mut StaticSlice) -> gimli::Result<constants::DwEhPe> {
let eh_pe = input.read_u8()?;
let eh_pe = constants::DwEhPe(eh_pe);
if eh_pe.is_valid_encoding() {
Ok(eh_pe)
} else {
Err(gimli::Error::UnknownPointerEncoding)
}
}
fn parse_encoded_pointer(
encoding: constants::DwEhPe,
unwind_ctx: &UnwindContext<'_>,
input: &mut StaticSlice,
) -> gimli::Result<Pointer> {
if encoding == constants::DW_EH_PE_omit {
return Err(Error::CannotParseOmitPointerEncoding);
}
let base = match encoding.application() {
constants::DW_EH_PE_absptr => 0,
constants::DW_EH_PE_pcrel => input.slice().as_ptr() as u64,
constants::DW_EH_PE_textrel => _Unwind_GetTextRelBase(unwind_ctx) as u64,
constants::DW_EH_PE_datarel => _Unwind_GetDataRelBase(unwind_ctx) as u64,
constants::DW_EH_PE_funcrel => _Unwind_GetRegionStart(unwind_ctx) as u64,
constants::DW_EH_PE_aligned => return Err(Error::UnsupportedPointerEncoding),
_ => unreachable!(),
};
let offset = match encoding.format() {
constants::DW_EH_PE_absptr => input.read_address(mem::size_of::<usize>() as _),
constants::DW_EH_PE_uleb128 => input.read_uleb128(),
constants::DW_EH_PE_udata2 => input.read_u16().map(u64::from),
constants::DW_EH_PE_udata4 => input.read_u32().map(u64::from),
constants::DW_EH_PE_udata8 => input.read_u64(),
constants::DW_EH_PE_sleb128 => input.read_sleb128().map(|a| a as u64),
constants::DW_EH_PE_sdata2 => input.read_i16().map(|a| a as u64),
constants::DW_EH_PE_sdata4 => input.read_i32().map(|a| a as u64),
constants::DW_EH_PE_sdata8 => input.read_i64().map(|a| a as u64),
_ => unreachable!(),
}?;
let address = base.wrapping_add(offset);
Ok(if encoding.is_indirect() {
Pointer::Indirect(address)
} else {
Pointer::Direct(address)
})
}
fn find_eh_action(
reader: &mut StaticSlice,
unwind_ctx: &UnwindContext<'_>,
) -> gimli::Result<EHAction> {
let func_start = _Unwind_GetRegionStart(unwind_ctx);
let mut ip_before_instr = 0;
let ip = _Unwind_GetIPInfo(unwind_ctx, &mut ip_before_instr);
let ip = if ip_before_instr != 0 { ip } else { ip - 1 };
let start_encoding = parse_pointer_encoding(reader)?;
let lpad_base = if !start_encoding.is_absent() {
unsafe { deref_pointer(parse_encoded_pointer(start_encoding, unwind_ctx, reader)?) }
} else {
func_start
};
let ttype_encoding = parse_pointer_encoding(reader)?;
if !ttype_encoding.is_absent() {
reader.read_uleb128()?;
}
let call_site_encoding = parse_pointer_encoding(reader)?;
let call_site_table_length = reader.read_uleb128()?;
reader.truncate(call_site_table_length as _)?;
while !reader.is_empty() {
let cs_start = unsafe {
deref_pointer(parse_encoded_pointer(
call_site_encoding,
unwind_ctx,
reader,
)?)
};
let cs_len = unsafe {
deref_pointer(parse_encoded_pointer(
call_site_encoding,
unwind_ctx,
reader,
)?)
};
let cs_lpad = unsafe {
deref_pointer(parse_encoded_pointer(
call_site_encoding,
unwind_ctx,
reader,
)?)
};
let cs_action = reader.read_uleb128()?;
if ip < func_start + cs_start {
break;
}
if ip < func_start + cs_start + cs_len {
if cs_lpad == 0 {
return Ok(EHAction::None);
} else {
let lpad = lpad_base + cs_lpad;
return Ok(match cs_action {
0 => EHAction::Cleanup(lpad),
_ => EHAction::Catch(lpad),
});
}
}
}
Ok(EHAction::None)
}
#[lang = "eh_personality"]
unsafe fn rust_eh_personality(
version: c_int,
actions: UnwindAction,
_exception_class: u64,
exception: *mut UnwindException,
unwind_ctx: &mut UnwindContext<'_>,
) -> UnwindReasonCode {
if version != 1 {
return UnwindReasonCode::FATAL_PHASE1_ERROR;
}
let lsda = _Unwind_GetLanguageSpecificData(unwind_ctx);
if lsda.is_null() {
return UnwindReasonCode::CONTINUE_UNWIND;
}
let mut lsda = EndianSlice::new(unsafe { get_unlimited_slice(lsda as _) }, NativeEndian);
let eh_action = match find_eh_action(&mut lsda, unwind_ctx) {
Ok(v) => v,
Err(_) => return UnwindReasonCode::FATAL_PHASE1_ERROR,
};
if actions.contains(UnwindAction::SEARCH_PHASE) {
match eh_action {
EHAction::None | EHAction::Cleanup(_) => UnwindReasonCode::CONTINUE_UNWIND,
EHAction::Catch(_) => UnwindReasonCode::HANDLER_FOUND,
}
} else {
match eh_action {
EHAction::None => UnwindReasonCode::CONTINUE_UNWIND,
EHAction::Cleanup(lpad) | EHAction::Catch(lpad) => {
_Unwind_SetGR(
unwind_ctx,
Arch::UNWIND_DATA_REG.0 .0 as _,
exception as usize,
);
_Unwind_SetGR(unwind_ctx, Arch::UNWIND_DATA_REG.1 .0 as _, 0);
_Unwind_SetIP(unwind_ctx, lpad);
UnwindReasonCode::INSTALL_CONTEXT
}
}
}
}
|
