user: 请从给定的汇编指令推导出C源代码:

```asm
<sayHello>:
  endbr64
  push   %rbp
  push   %rbx
  sub    $0x18,%rsp
  mov    %edi,%ebx
  mov    %rsi,%rbp
  mov    %fs:0x28,%rax
  mov    %rax,0x8(%rsp)
  xor    %eax,%eax
  movl   $0x0,(%rsp)
  mov    %rsi,%rdi
  call   <strlen@plt>
  add    $0x1,%eax
  mov    %eax,0x4(%rsp)
  mov    %rsp,%rsi
  mov    $0x4,%edx
  mov    %ebx,%edi
  mov    $0x0,%eax
  call   <write@plt>
  cmp    $0xffffffff,%eax
  je     L77
L14:
  mov    %rsp,%rsi
  mov    $0x4,%edx
  mov    %ebx,%edi
  call   <read@plt>
  cmp    $0x4,%eax
  jne    L40
  cmpl   $0x0,(%rsp)
  je     L62
L40:
  lea    D54(%rip),%rdi
  call   <fatalError@plt>
L62:
  lea    0x4(%rsp),%rsi
  mov    $0x4,%edx
  mov    %ebx,%edi
  mov    $0x0,%eax
  call   <write@plt>
  cmp    $0xffffffff,%eax
  je     L115
L20:
  mov    %rsp,%rsi
  mov    $0x4,%edx
  mov    %ebx,%edi
  call   <read@plt>
  cmp    $0x4,%eax
  jne    L85
  cmpl   $0x0,(%rsp)
  je     L106
L85:
  lea    D28(%rip),%rdi
  call   <fatalError@plt>
L106:
  mov    0x4(%rsp),%edx
  cmp    $0x1,%edx
  jne    L22
L81:
  mov    0x8(%rsp),%rax
  sub    %fs:0x28,%rax
  jne    L79
  mov    $0x0,%eax
  add    $0x18,%rsp
  pop    %rbx
  pop    %rbp
  ret
L77:
  lea    D49(%rip),%rdi
  call   <fatalError@plt>
  jmp    L14
L115:
  lea    D18(%rip),%rdi
  call   <fatalError@plt>
  jmp    L20
L22:
  mov    %rbp,%rsi
  mov    %ebx,%edi
  mov    $0x0,%eax
  call   <write@plt>
  cmp    $0xffffffff,%eax
  je     L47
L136:
  mov    %rsp,%rsi
  mov    $0x4,%edx
  mov    %ebx,%edi
  call   <read@plt>
  cmp    $0x4,%eax
  jne    L103
  cmpl   $0x0,(%rsp)
  je     L81
L103:
  lea    D5(%rip),%rdi
  call   <fatalError@plt>
  jmp    L81
L47:
  lea    D25(%rip),%rdi
  call   <fatalError@plt>
  jmp    L136
L79:
  call   <__stack_chk_fail@plt>
```

tool_calls: name: unpack_data
arguments: label: D54
type_guessed: string
name: unpack_data
arguments: label: D28
type_guessed: string
name: unpack_data
arguments: label: D49
type_guessed: string
name: unpack_data
arguments: label: D18
type_guessed: string
name: unpack_data
arguments: label: D5
type_guessed: string
name: unpack_data
arguments: label: D25
type_guessed: string

tool: D54: Client protocol error 2

tool: D28: Client protocol error 4

tool: D49: Client protocol error 0

tool: D18: Client protocol error 3

tool: D5: Client protocol error 6

tool: D25: Client protocol error 5

assistant: ```c
int sayHello(int socketFD, char *username) {
  int serverResponse = 0;
  int argLength = strlen(username) + 1;
  int n = 0;
  if (write(socketFD, &serverResponse, 4) == -1)
    fatalError("Client protocol error 0");
  n = read(socketFD, &serverResponse, 4);
  if (n != 4 || serverResponse != 0) {
    fatalError("Client protocol error 2");
  }
  if (write(socketFD, &argLength, 4) == -1)
    fatalError("Client protocol error 3");
  n = read(socketFD, &serverResponse, 4);
  if (n != 4 || serverResponse != 0)
    fatalError("Client protocol error 4");
  if (argLength != 1) {
    if ((n = write(socketFD, username, argLength)) == -1)
      fatalError("Client protocol error 5");
    n = read(socketFD, &serverResponse, 4);
    if (n != 4 || serverResponse != 0)
      fatalError("Client protocol error 6");
  }
  return 0;
}
```