Create a ELF file with ELFIO

[Alexandre Bencz]

Hi :)

I see the sample of ELF file creation, but, I did not understand how you get the offset of "Hello World!" string:

"'\xB9', '\x20', '\x80', '\x04', '\x08', // mov ecx, msg"

I have created a lib in C++, and, C# to create a MZ PE ( coff ), and, i solve this problem with something very intresting, look that sample:

"
...
mov(ebx, 0);
Address label2(0, Abs);
jmp(label2);
auto label1 = curtext->addr();
push(ebx);
push(pe.str("%d\n"));
call(ptr[pe.import("msvcrt.dll", "printf")]);
add(esp, 8);
curtext->put(label2);
inc(ebx);
cmp(ebx, 10);
jnz(label1);
push(0);
call(ptr[pe.import("msvcrt.dll", "exit")]);
jmp(curtext->addr());
...
"

See the code here :)
https://gist.github.com/bencz/4414040

[Serge Lamikhov-Center]

Hi,

The address of 'msg' string is encoded into the 'mov' instruction itself:
'\x20', '\x80', '\x04', '\x08' == 0x08048020
This is the exact address of the data segment for this program.

It is done for demonstration and simplification purposes.

Alternatively, it is possible to use a relocation entry and corresponding symbol definition.

An example of the alternative method can be found in 'write_obj' example directory.

Best regards,
Serge