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
|
/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Debug.h>
#include <AK/OwnPtr.h>
#include <AK/QuickSort.h>
#include <AK/Vector.h>
#include <LibCore/ArgsParser.h>
#include <LibCore/MappedFile.h>
#include <LibELF/Image.h>
#include <LibX86/Disassembler.h>
#include <LibX86/ELFSymbolProvider.h>
#include <string.h>
int main(int argc, char** argv)
{
const char* path = nullptr;
Core::ArgsParser args_parser;
args_parser.set_general_help(
"Disassemble an executable, and show human-readable "
"assembly code for each function.");
args_parser.add_positional_argument(path, "Path to i386 binary file", "path");
args_parser.parse(argc, argv);
auto file_or_error = Core::MappedFile::map(path);
if (file_or_error.is_error()) {
warnln("Could not map file: {}", file_or_error.error());
return 1;
}
auto& file = *file_or_error.value();
struct Symbol {
size_t value;
size_t size;
StringView name;
size_t address() const { return value; }
size_t address_end() const { return value + size; }
bool contains(size_t virtual_address) { return address() <= virtual_address && virtual_address < address_end(); }
};
Vector<Symbol> symbols;
const u8* asm_data = (const u8*)file.data();
size_t asm_size = file.size();
size_t file_offset = 0;
Vector<Symbol>::Iterator current_symbol = symbols.begin();
OwnPtr<X86::ELFSymbolProvider> symbol_provider; // nullptr for non-ELF disassembly.
OwnPtr<ELF::Image> elf;
if (asm_size >= 4 && strncmp((const char*)asm_data, "\u007fELF", 4) == 0) {
elf = make<ELF::Image>(asm_data, asm_size);
if (elf->is_valid()) {
symbol_provider = make<X86::ELFSymbolProvider>(*elf);
elf->for_each_section_of_type(SHT_PROGBITS, [&](const ELF::Image::Section& section) {
// FIXME: Disassemble all SHT_PROGBITS sections, not just .text.
if (section.name() != ".text")
return IterationDecision::Continue;
asm_data = (const u8*)section.raw_data();
asm_size = section.size();
file_offset = section.address();
return IterationDecision::Break;
});
symbols.ensure_capacity(elf->symbol_count() + 1);
symbols.append({ 0, 0, StringView() }); // Sentinel.
elf->for_each_symbol([&](const ELF::Image::Symbol& symbol) {
symbols.append({ symbol.value(), symbol.size(), symbol.name() });
return IterationDecision::Continue;
});
quick_sort(symbols, [](auto& a, auto& b) {
if (a.value != b.value)
return a.value < b.value;
if (a.size != b.size)
return a.size < b.size;
return a.name < b.name;
});
if constexpr (DISASM_DUMP_DEBUG) {
for (size_t i = 0; i < symbols.size(); ++i)
dbgln("{}: {:p}, {}", symbols[i].name, symbols[i].value, symbols[i].size);
}
}
}
X86::SimpleInstructionStream stream(asm_data, asm_size);
X86::Disassembler disassembler(stream);
bool is_first_symbol = true;
bool current_instruction_is_in_symbol = false;
for (;;) {
auto offset = stream.offset();
auto insn = disassembler.next();
if (!insn.has_value())
break;
// Prefix regions of instructions belonging to a symbol with the symbol's name.
// Separate regions of instructions belonging to distinct symbols with newlines,
// and separate regions of instructions not belonging to symbols from regions belonging to symbols with newlines.
// Interesting cases:
// - More than 1 symbol covering a region of instructions (ICF, D1/D2)
// - Symbols of size 0 that don't cover any instructions but are at an address (want to print them, separated from instructions both before and after)
// Invariant: current_symbol is the largest instruction containing insn, or it is the largest instruction that has an address less than the instruction's address.
size_t virtual_offset = file_offset + offset;
if (current_symbol < symbols.end() && !current_symbol->contains(virtual_offset)) {
if (!is_first_symbol && current_instruction_is_in_symbol) {
// The previous instruction was part of a symbol that doesn't cover the current instruction, so separate it from the current instruction with a newline.
outln();
current_instruction_is_in_symbol = (current_symbol + 1 < symbols.end() && (current_symbol + 1)->contains(virtual_offset));
}
// Try to find symbol covering current instruction, if one exists.
while (current_symbol + 1 < symbols.end() && !(current_symbol + 1)->contains(virtual_offset) && (current_symbol + 1)->address() <= virtual_offset) {
++current_symbol;
if (!is_first_symbol)
outln("\n({} ({:p}-{:p}))\n", current_symbol->name, current_symbol->address(), current_symbol->address_end());
}
while (current_symbol + 1 < symbols.end() && (current_symbol + 1)->contains(virtual_offset)) {
if (!is_first_symbol && !current_instruction_is_in_symbol)
outln();
++current_symbol;
current_instruction_is_in_symbol = true;
outln("{} ({:p}-{:p}):", current_symbol->name, current_symbol->address(), current_symbol->address_end());
}
is_first_symbol = false;
}
outln("{:p} {}", virtual_offset, insn.value().to_string(virtual_offset, symbol_provider));
}
}
|
