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

```asm
<http_request_headers>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x418,%rsp
  mov    %edi,%r15d
  mov    %fs:0x28,%rax
  mov    %rax,0x408(%rsp)
  xor    %eax,%eax
  lea    D20(%rip),%rdi
  call   <touch@plt>
  lea    D32(%rip),%r12
  jmp    L4
L85:
  mov    %dl,0x0(%r13)
  add    $0x1,%ebp
  add    $0x1,%rbx
L151:
  mov    %r12,%rdi
  call   <strlen@plt>
  cmp    %ebp,%eax
  jle    L40
  mov    %rbx,%r13
  movsbl (%rbx),%edi
  call   <toupper@plt>
  mov    %al,(%rbx)
  mov    $0x5f,%edx
  cmp    $0x2d,%al
  je     L85
  mov    %eax,%edx
  jmp    L85
L40:
  mov    %rsp,%rdi
  mov    $0x200,%edx
  mov    %r14,%rsi
  call   <url_decode@plt>
  lea    D43(%rip),%rsi
  mov    %r12,%rdi
  call   <strcmp@plt>
  test   %rax,%rax
  je     L8
  lea    D56(%rip),%rsi
  mov    %r12,%rdi
  call   <strcmp@plt>
  test   %rax,%rax
  jne    L175
L8:
  mov    %rsp,%rsi
  mov    $0x1,%edx
  mov    %r12,%rdi
  call   <setenv@plt>
L4:
  mov    $0x2000,%edx
  mov    %r12,%rsi
  mov    %r15d,%edi
  call   <http_read_line@plt>
  test   %rax,%rax
  js     L42
  cmpb   $0x0,(%r12)
  je     L143
  mov    $0x20,%esi
  mov    %r12,%rdi
  call   <strchr@plt>
  test   %rax,%rax
  je     L26
  movb   $0x0,(%rax)
  lea    0x1(%rax),%r14
  mov    %r12,%rdi
  call   <strlen@plt>
  test   %eax,%eax
  je     L58
  mov    %r12,%rdi
  call   <strlen@plt>
  sub    $0x1,%eax
  movslq %eax,%rdx
  cmpb   $0x3a,(%r12,%rdx,1)
  jne    L11
  movb   $0x0,(%r12,%rdx,1)
  mov    %r12,%rbx
  mov    $0x0,%ebp
  jmp    L151
L175:
  lea    0x200(%rsp),%rbx
  mov    %r12,%rcx
  lea    D24(%rip),%rdx
  mov    $0x200,%esi
  mov    %rbx,%rdi
  call   <snprintf@plt>
  mov    %rsp,%rsi
  mov    $0x1,%edx
  mov    %rbx,%rdi
  call   <setenv@plt>
  jmp    L4
L42:
  lea    D59(%rip),%rax
L5:
  mov    0x408(%rsp),%rdx
  sub    %fs:0x28,%rdx
  jne    L137
  add    $0x418,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L143:
  mov    $0x0,%eax
  jmp    L5
L26:
  lea    D9(%rip),%rax
  jmp    L5
L58:
  lea    D18(%rip),%rax
  jmp    L5
L11:
  lea    D74(%rip),%rax
  jmp    L5
L137:
  call   <__stack_chk_fail@plt>
```

tool_calls: name: parse_data
arguments: data_label: D20
data_type: string
name: parse_data
arguments: data_label: D43
data_type: string
name: parse_data
arguments: data_label: D56
data_type: string
name: parse_data
arguments: data_label: D24
data_type: string
name: parse_data
arguments: data_label: D59
data_type: string
name: parse_data
arguments: data_label: D9
data_type: string
name: parse_data
arguments: data_label: D18
data_type: string
name: parse_data
arguments: data_label: D74
data_type: string

tool: D20: http_request_headers

tool: D43: CONTENT_TYPE

tool: D56: CONTENT_LENGTH

tool: D24: HTTP_%s

tool: D59: Socket IO error

tool: D9: Header parse error (1)

tool: D18: Header parse error (2)

tool: D74: Header parse error (3)

assistant: ```c
const char *http_request_headers(int fd) {
  static char buf[8192];
  int i;
  char value[512];
  char envvar[512];
  touch("http_request_headers");
  for (;;) {
    if (http_read_line(fd, buf, sizeof(buf)) < 0)
      return "Socket IO error";
    if (buf[0] == '\0')
      break;
    char *sp = strchr(buf, ' ');
    if (!sp)
      return "Header parse error (1)";
    *sp = '\0';
    sp++;
    if (strlen(buf) == 0)
      return "Header parse error (2)";
    char *colon = &buf[strlen(buf) - 1];
    if (*colon != ':')
      return "Header parse error (3)";
    *colon = '\0';
    for (i = 0; i < strlen(buf); i++) {
      buf[i] = toupper(buf[i]);
      if (buf[i] == '-')
        buf[i] = '_';
    }
    url_decode(value, sp, 512);
    if (strcmp(buf, "CONTENT_TYPE") != 0 && strcmp(buf, "CONTENT_LENGTH") != 0) {
      snprintf(envvar, 512, "HTTP_%s", buf);
      setenv(envvar, value, 1);
    } else {
      setenv(buf, value, 1);
    }
  }
  return 0;
}
```