user: 请显示与下面列出的汇编代码相匹配的C语言实现：

```asm
<authunix_create_default>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  push   %r14
  push   %r13
  push   %r12
  push   %rbx
  sub    $0x40,%rsp
  mov    %fs:0x28,%rax
  mov    %rax,-0x28(%rbp)
  xor    %eax,%eax
  mov    %rsp,%rax
  mov    %rax,%r14
  mov    D16(%rip),%rax
  mov    (%rax),%eax
  add    $0x1,%eax
  movslq %eax,%rdx
  sub    $0x1,%rdx
  mov    %rdx,-0x48(%rbp)
  movslq %eax,%rdx
  mov    %rdx,%rsi
  mov    $0x0,%edi
  movslq %eax,%rdx
  mov    %rdx,%rcx
  mov    $0x0,%ebx
  cltq
  mov    $0x10,%edx
  sub    $0x1,%rdx
  add    %rdx,%rax
  mov    $0x10,%edi
  mov    $0x0,%edx
  div    %rdi
  imul   $0x10,%rax,%rax
  mov    %rax,%rcx
  and    $0xfffffffffffff000,%rcx
  mov    %rsp,%rdx
  sub    %rcx,%rdx
L9:
  cmp    %rdx,%rsp
  je     L28
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  jmp    L9
L28:
  mov    %rax,%rdx
  and    $0xfff,%edx
  sub    %rdx,%rsp
  mov    %rax,%rdx
  and    $0xfff,%edx
  test   %rdx,%rdx
  je     L39
  and    $0xfff,%eax
  sub    $0x8,%rax
  add    %rsp,%rax
  orq    $0x0,(%rax)
L39:
  mov    %rsp,%rax
  add    $0x0,%rax
  mov    %rax,-0x40(%rbp)
  mov    D12(%rip),%rax
  mov    (%rax),%eax
  mov    %eax,%edi
  call   <sysconf@plt>
  mov    %eax,-0x4c(%rbp)
  mov    -0x4c(%rbp),%eax
  movslq %eax,%rdx
  sub    $0x1,%rdx
  mov    %rdx,-0x38(%rbp)
  movslq %eax,%rdx
  mov    %rdx,-0x60(%rbp)
  movq   $0x0,-0x58(%rbp)
  movslq %eax,%rdx
  mov    %rdx,%r12
  mov    $0x0,%r13d
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    $0x10,%eax
  sub    $0x1,%rax
  add    %rdx,%rax
  mov    $0x10,%ebx
  mov    $0x0,%edx
  div    %rbx
  imul   $0x10,%rax,%rax
  mov    %rax,%rcx
  and    $0xfffffffffffff000,%rcx
  mov    %rsp,%rdx
  sub    %rcx,%rdx
L82:
  cmp    %rdx,%rsp
  je     L87
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  jmp    L82
L87:
  mov    %rax,%rdx
  and    $0xfff,%edx
  sub    %rdx,%rsp
  mov    %rax,%rdx
  and    $0xfff,%edx
  test   %rdx,%rdx
  je     L45
  and    $0xfff,%eax
  sub    $0x8,%rax
  add    %rsp,%rax
  orq    $0x0,(%rax)
L45:
  mov    %rsp,%rax
  add    $0x3,%rax
  shr    $0x2,%rax
  shl    $0x2,%rax
  mov    %rax,-0x30(%rbp)
  mov    D16(%rip),%rax
  mov    (%rax),%edx
  mov    -0x40(%rbp),%rax
  mov    %edx,%esi
  mov    %rax,%rdi
  call   <gethostname@plt>
  cmp    $0xffffffff,%eax
  jne    L81
  mov    $0x0,%eax
  call   <abort@plt>
L81:
  mov    D16(%rip),%rax
  mov    (%rax),%eax
  mov    -0x40(%rbp),%rdx
  cltq
  movb   $0x0,(%rdx,%rax,1)
  mov    $0x0,%eax
  call   <geteuid@plt>
  mov    %eax,%r12d
  mov    $0x0,%eax
  call   <getegid@plt>
  mov    %eax,%r13d
  mov    -0x30(%rbp),%rdx
  mov    -0x4c(%rbp),%eax
  mov    %rdx,%rsi
  mov    %eax,%edi
  call   <getgroups@plt>
  mov    %eax,%ebx
  test   %ebx,%ebx
  jns    L52
  mov    $0x0,%eax
  call   <abort@plt>
L52:
  mov    D22(%rip),%rax
  mov    (%rax),%eax
  cmp    %eax,%ebx
  cmovle %ebx,%eax
  mov    %eax,%edx
  mov    -0x30(%rbp),%rcx
  mov    -0x40(%rbp),%rax
  mov    %rcx,%r8
  mov    %edx,%ecx
  mov    %r13d,%edx
  mov    %r12d,%esi
  mov    %rax,%rdi
  call   <authunix_create@plt>
  mov    %r14,%rsp
  mov    -0x28(%rbp),%rdx
  sub    %fs:0x28,%rdx
  je     L46
  call   <__stack_chk_fail@plt>
L46:
  lea    -0x20(%rbp),%rsp
  pop    %rbx
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %rbp
  ret
```

assistant: ```c
AUTH *authunix_create_default() {
  register int len;
  char machname[MAX_MACHINE_NAME + 1];
  register uid_t uid;
  register gid_t gid;
  int max_nr_groups = sysconf(_SC_NGROUPS_MAX);
  gid_t gids[max_nr_groups];
  if (gethostname(machname, MAX_MACHINE_NAME) == -1)
    abort();
  machname[MAX_MACHINE_NAME] = 0;
  uid = geteuid();
  gid = getegid();
  if ((len = getgroups(max_nr_groups, gids)) < 0)
    abort();
  return (authunix_create(machname, uid, gid, (((NGRPS) < (len)) ? (NGRPS) : (len)), gids));
}
```