Ecosyste.ms: Awesome
An open API service indexing awesome lists of open source software.
https://github.com/m4b/faerie
Magical ELF and Mach-o object file writer backend
https://github.com/m4b/faerie
compiler elf mach object-files
Last synced: 20 days ago
JSON representation
Magical ELF and Mach-o object file writer backend
- Host: GitHub
- URL: https://github.com/m4b/faerie
- Owner: m4b
- License: mit
- Created: 2016-11-08T05:57:55.000Z (almost 8 years ago)
- Default Branch: master
- Last Pushed: 2024-04-08T01:57:03.000Z (7 months ago)
- Last Synced: 2024-10-05T13:20:08.700Z (about 1 month ago)
- Topics: compiler, elf, mach, object-files
- Language: Rust
- Homepage:
- Size: 328 KB
- Stars: 265
- Watchers: 10
- Forks: 26
- Open Issues: 19
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# faerie [](https://github.com/m4b/faerie/actions) [](https://docs.rs/faerie).
Emit some object files, at your leisure:
```rust
use faerie::{ArtifactBuilder, ArtifactError, triple, Link, Decl};
use std::path::Path;
use std::fs::File;
pub fn main() -> Result<(), ArtifactError> {
let name = "test.o";
let file = File::create(Path::new(name))?;
let mut obj = ArtifactBuilder::new(triple!("x86_64-unknown-unknown-unknown-elf"))
.name(name.to_owned())
.finish();
// first we declare our symbolic references;
// it is a runtime error to define a symbol _without_ declaring it first
obj.declarations(
[
("deadbeef", Decl::function().into()),
("main", Decl::function().global().into()),
("str.1", Decl::cstring().into()),
("DEADBEEF", Decl::data_import().into()),
("printf", Decl::function_import().into()),
].iter().cloned()
)?;
// we now define our local functions and data
// 0000000000000000 :
// 0: 55 push %rbp
// 1: 48 89 e5 mov %rsp,%rbp
// 4: 48 8b 05 00 00 00 00 mov 0x0(%rip),%rax # b
// 7: R_X86_64_GOTPCREL DEADBEEF-0x4
// b: 8b 08 mov (%rax),%ecx
// d: 83 c1 01 add $0x1,%ecx
// 10: 89 c8 mov %ecx,%eax
// 12: 5d pop %rbp
// 13: c3 retq
obj.define("deadbeef",
vec![0x55,
0x48, 0x89, 0xe5,
0x48, 0x8b, 0x05, 0x00, 0x00, 0x00, 0x00,
0x8b, 0x08,
0x83, 0xc1, 0x01,
0x89, 0xc8,
0x5d,
0xc3])?;
// main:
// 55 push %rbp
// 48 89 e5 mov %rsp,%rbp
// b8 00 00 00 00 mov $0x0,%eax
// e8 00 00 00 00 callq 0x0
// 89 c6 mov %eax,%esi
// 48 8d 3d 00 00 00 00 lea 0x0(%rip),%rdi # will be: deadbeef: 0x%x\n
// b8 00 00 00 00 mov $0x0,%eax
// e8 00 00 00 00 callq 0x3f # printf
// b8 00 00 00 00 mov $0x0,%eax
// 5d pop %rbp
// c3 retq
obj.define("main",
vec![0x55,
0x48, 0x89, 0xe5,
0xb8, 0x00, 0x00, 0x00, 0x00,
0xe8, 0x00, 0x00, 0x00, 0x00,
0x89, 0xc6,
0x48, 0x8d, 0x3d, 0x00, 0x00, 0x00, 0x00,
0xb8, 0x00, 0x00, 0x00, 0x00,
0xe8, 0x00, 0x00, 0x00, 0x00,
0xb8, 0x00, 0x00, 0x00, 0x00,
0x5d,
0xc3])?;
obj.define("str.1", b"deadbeef: 0x%x\n\0".to_vec())?;
// Next, we declare our relocations,
// which are _always_ relative to the `from` symbol
obj.link(Link { from: "main", to: "str.1", at: 19 })?;
obj.link(Link { from: "main", to: "printf", at: 29 })?;
obj.link(Link { from: "main", to: "deadbeef", at: 10 })?;
obj.link(Link { from: "deadbeef", to: "DEADBEEF", at: 7 })?;
// Finally, we write the object file
obj.write(file)?;
Ok(())
}
```
Will emit an object file like this:
ELF REL X86_64-little-endian @ 0x0:
e_phoff: 0x0 e_shoff: 0x2a2 e_flags: 0x0 e_ehsize: 64 e_phentsize: 56 e_phnum: 0 e_shentsize: 64 e_shnum: 9 e_shstrndx: 1
SectionHeaders(9):
Idx Name Type Flags Offset Addr Size Link Entsize Align
0 SHT_NULL 0x0 0x0 0x0 0x0 0x0
1 .strtab SHT_STRTAB 0x8c 0x0 0xc6 0x0 0x1
2 .symtab SHT_SYMTAB 0x152 0x0 0xf0 .strtab(1) 0x18 0x8
3 .rodata.str.1 SHT_PROGBITS ALLOC MERGE STRINGS 0x40 0x0 0x10 0x1 0x1
4 .text.deadbeef SHT_PROGBITS ALLOC EXECINSTR 0x50 0x0 0x14 0x0 0x10
5 .text.main SHT_PROGBITS ALLOC EXECINSTR 0x64 0x0 0x28 0x0 0x10
6 .reloc.main SHT_RELA 0x242 0x0 0x48 .symtab(2) 0x18 0x8
7 .reloc.deadbeef SHT_RELA 0x28a 0x0 0x18 .symtab(2) 0x18 0x8
8 .note.GNU-stack SHT_PROGBITS 0x0 0x0 0x0 0x0 0x1
Syms(10):
Addr Bind Type Symbol Size Section Other
0 LOCAL NOTYPE 0x0 0x0
0 LOCAL FILE test.o 0x0 ABS 0x0
0 LOCAL SECTION 0x0 .rodata.str.1(3) 0x0
0 LOCAL SECTION 0x0 .text.deadbeef(4) 0x0
0 LOCAL SECTION 0x0 .text.main(5) 0x0
0 LOCAL OBJECT str.1 0x10 .rodata.str.1(3) 0x0
0 LOCAL FUNC deadbeef 0x14 .text.deadbeef(4) 0x0
0 GLOBAL FUNC main 0x28 .text.main(5) 0x0
0 GLOBAL NOTYPE DEADBEEF 0x0 0x0
0 GLOBAL NOTYPE printf 0x0 0x0
Shdr Relocations(4):
.text.main(3)
13 X86_64_PC32 .rodata.str.1
1d X86_64_PLT32 printf+-4
a X86_64_PLT32 .text.deadbeef+-4
.text.deadbeef(1)
7 X86_64_GOTPCREL DEADBEEF+-4
:sunglasses: