clone

pub fn clone() callconv(.naked) u32

File

Code

pub fn clone() callconv(.naked) u32 {
    // __clone(func, stack, flags, arg, ptid, tls, ctid)
    //         +8,   +12,   +16,   +20, +24,  +28, +32
    //
    // syscall(SYS_clone, flags, stack, ptid, tls, ctid)
    //         eax,       ebx,   ecx,   edx,  esi, edi
    asm volatile (
        \\  pushl %%ebp
        \\  movl %%esp,%%ebp
        \\  pushl %%ebx
        \\  pushl %%esi
        \\  pushl %%edi
        \\  // Setup the arguments
        \\  movl 16(%%ebp),%%ebx
        \\  movl 12(%%ebp),%%ecx
        \\  andl $-16,%%ecx
        \\  subl $20,%%ecx
        \\  movl 20(%%ebp),%%eax
        \\  movl %%eax,4(%%ecx)
        \\  movl 8(%%ebp),%%eax
        \\  movl %%eax,0(%%ecx)
        \\  movl 24(%%ebp),%%edx
        \\  movl 28(%%ebp),%%esi
        \\  movl 32(%%ebp),%%edi
        \\  movl $120,%%eax // SYS_clone
        \\  int $128
        \\  testl %%eax,%%eax
        \\  jz 1f
        \\  popl %%edi
        \\  popl %%esi
        \\  popl %%ebx
        \\  popl %%ebp
        \\  retl
        \\
        \\1:
    );
    if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
        \\  .cfi_undefined %%eip
    );
    asm volatile (
        \\  xorl %%ebp,%%ebp
        \\
        \\  popl %%eax
        \\  calll *%%eax
        \\  movl %%eax,%%ebx
        \\  movl $1,%%eax // SYS_exit
        \\  int $128
    );
}