user: Demonstrate the C code that generates the assembly output below:

```asm
<is_a_symlink>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  lea    -0x9000(%rsp),%r11
L87:
  sub    $0x1000,%rsp
  orq    $0x0,(%rsp)
  cmp    %r11,%rsp
  jne    L87
  sub    $0x38,%rsp
  mov    %fs:0x28,%rax
  mov    %rax,0x9028(%rsp)
  xor    %eax,%eax
  cmp    $0x14,%esi
  je     L177
  lea    0x20(%rsp),%rbp
  mov    %esi,%ebx
  mov    $0x1000,%edx
  mov    %rbp,%rsi
  call   <readlink@plt>
  movb   $0x0,0x20(%rsp,%rax,1)
  cmp    $0x13,%ebx
  je     L42
  lea    0x1020(%rsp),%r12
  mov    $0x1000,%edx
  mov    %rbp,%rdi
  mov    %r12,%rsi
  call   <readlink@plt>
  movb   $0x0,0x1020(%rsp,%rax,1)
  cmp    $0x12,%ebx
  je     L145
  lea    0x2020(%rsp),%r13
  mov    $0x1000,%edx
  mov    %r12,%rdi
  mov    %r13,%rsi
  call   <readlink@plt>
  movb   $0x0,0x2020(%rsp,%rax,1)
  cmp    $0x11,%ebx
  je     L209
  lea    0x3020(%rsp),%r14
  mov    $0x1000,%edx
  mov    %r13,%rdi
  mov    %r14,%rsi
  call   <readlink@plt>
  movb   $0x0,0x3020(%rsp,%rax,1)
  cmp    $0x10,%ebx
  je     L213
  lea    0x4020(%rsp),%r15
  mov    $0x1000,%edx
  mov    %r14,%rdi
  mov    %r15,%rsi
  call   <readlink@plt>
  movb   $0x0,0x4020(%rsp,%rax,1)
  cmp    $0xf,%ebx
  je     L71
  lea    0x5020(%rsp),%rax
  mov    $0x1000,%edx
  mov    %r15,%rdi
  mov    %rax,%rsi
  mov    %rax,(%rsp)
  call   <readlink@plt>
  movb   $0x0,0x5020(%rsp,%rax,1)
  cmp    $0xe,%ebx
  je     L11
  lea    0x6020(%rsp),%rcx
  mov    (%rsp),%rdi
  mov    $0x1000,%edx
  mov    %rcx,%rsi
  mov    %rcx,0x8(%rsp)
  call   <readlink@plt>
  movb   $0x0,0x6020(%rsp,%rax,1)
  cmp    $0xd,%ebx
  je     L9
  lea    0x7020(%rsp),%r8
  mov    0x8(%rsp),%rdi
  mov    $0x1000,%edx
  mov    %r8,%rsi
  mov    %r8,0x10(%rsp)
  call   <readlink@plt>
  cmp    $0xc,%ebx
  mov    0x10(%rsp),%r8
  movb   $0x0,0x7020(%rsp,%rax,1)
  je     L183
  lea    0x8020(%rsp),%r9
  mov    %r8,%rdi
  mov    $0x1000,%edx
  mov    %r8,0x18(%rsp)
  mov    %r9,%rsi
  mov    %r9,0x10(%rsp)
  call   <readlink@plt>
  mov    0x10(%rsp),%rdi
  lea    0x9(%rbx),%esi
  movb   $0x0,0x8020(%rsp,%rax,1)
  call   <is_a_symlink>
  mov    0x10(%rsp),%r9
  mov    0x18(%rsp),%r8
  test   %rax,%rax
  jne    L202
  mov    %r9,%rdi
  mov    %r8,0x10(%rsp)
  call   <strdup@plt>
  mov    0x10(%rsp),%r8
  test   %rax,%rax
  jne    L202
  nopl   0x0(%rax,%rax,1)
L183:
  mov    %r8,%rdi
  call   <strdup@plt>
  test   %rax,%rax
  jne    L202
  nopl   (%rax)
L9:
  mov    0x8(%rsp),%rdi
  call   <strdup@plt>
  test   %rax,%rax
  jne    L202
L11:
  mov    (%rsp),%rdi
  call   <strdup@plt>
  test   %rax,%rax
  jne    L202
L71:
  mov    %r15,%rdi
  call   <strdup@plt>
  test   %rax,%rax
  jne    L202
  nopw   0x0(%rax,%rax,1)
L213:
  mov    %r14,%rdi
  call   <strdup@plt>
  test   %rax,%rax
  jne    L202
  nopl   (%rax)
L209:
  mov    %r13,%rdi
  call   <strdup@plt>
  test   %rax,%rax
  jne    L202
  nopl   (%rax)
L145:
  mov    %r12,%rdi
  call   <strdup@plt>
  test   %rax,%rax
  je     L42
L202:
  mov    0x9028(%rsp),%rdx
  sub    %fs:0x28,%rdx
  jne    L104
  add    $0x9038,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopw   0x0(%rax,%rax,1)
L177:
  xor    %eax,%eax
  jmp    L202
  nopl   0x0(%rax)
L42:
  mov    %rbp,%rdi
  call   <strdup@plt>
  jmp    L202
L104:
  call   <__stack_chk_fail@plt>
```

assistant: ```c
char *is_a_symlink(const char *argv, int link_level) {
  ssize_t n;
  char link[4096];
  char *tmp_link;
  if (link_level == 20)
    return NULL;
  n = readlink(argv, link, 4096);
  if (n < 0)
    return NULL;
  link[n] = '\0';
  tmp_link = is_a_symlink(link, link_level + 1);
  if (!tmp_link)
    return strdup(link);
  return tmp_link;
}
```