elf_loader 0.12.0

A pure-rust library for loading all ELF format files from both memory and files.
Documentation 
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use elf::abi::*;

pub const EM_ARCH: u16 = EM_X86_64;
pub const TLS_DTV_OFFSET: usize = 0;

pub const REL_RELATIVE: u32 = R_X86_64_RELATIVE;
pub const REL_GOT: u32 = R_X86_64_GLOB_DAT;
pub const REL_DTPMOD: u32 = R_X86_64_DTPMOD64;
pub const REL_SYMBOLIC: u32 = R_X86_64_64;
pub const REL_JUMP_SLOT: u32 = R_X86_64_JUMP_SLOT;
pub const REL_DTPOFF: u32 = R_X86_64_DTPOFF64;
pub const REL_IRELATIVE: u32 = R_X86_64_IRELATIVE;
pub const REL_COPY: u32 = R_X86_64_COPY;
pub const REL_TPOFF: u32 = R_X86_64_TPOFF64;

#[cfg(feature = "lazy")]
core::arch::global_asm!(
    "
    .text
    .globl dl_runtime_resolve
	.type dl_runtime_resolve, @function
	.align 16
dl_runtime_resolve:
// 保存参数寄存器,这里多使用了8字节栈是为了栈的16字节对齐
    sub rsp,8*7
    mov [rsp+8*0],rdi
    mov [rsp+8*1],rsi
    mov [rsp+8*2],rdx
    mov [rsp+8*3],rcx
    mov [rsp+8*4],r8
    mov [rsp+8*5],r9
// 这两个是plt代码压入栈的
    mov rdi,[rsp+8*7]
    mov rsi,[rsp+8*8]
// 调用重定位函数
    call dl_fixup
// 恢复参数寄存器
    mov rdi,[rsp+8*0]
    mov rsi,[rsp+8*1]
    mov rdx,[rsp+8*2]
    mov rcx,[rsp+8*3]
    mov r8,[rsp+8*4]
    mov r9,[rsp+8*5]
// 需要把plt代码压入栈中的东西也弹出去
    add rsp,7*8+2*8
// 执行真正的函数
    jmp rax
"
);

#[cfg(feature = "lazy")]
#[inline]
pub(crate) fn prepare_lazy_bind(got: *mut usize, dylib: usize) {
    unsafe extern "C" {
        fn dl_runtime_resolve();
    }
    // 这是安全的，延迟绑定时库是存在的
    unsafe {
        got.add(1).write(dylib);
        got.add(2).write(dl_runtime_resolve as usize);
    }
}