使用Rust的windows-rs调用WlanGetAvailableNetworkList遇索引越界问题

尝试通过WlanGetAvailableNetworkList获取所有可用网络列表，但根据dwNumberOfItems遍历网络数组时，仅能显示第一个网络，索引超过0时触发index out of bounds: the len is 1 but the index is 1错误，代码如下：

let mut w_handle: HANDLE = HANDLE::default();
let mut current_version: u32 = 0;

if WIN32_ERROR(WlanOpenHandle(2, None, &mut current_version, &mut w_handle)) != ERROR_SUCCESS {
  return;
}

let mut wlan_interface_info_list = std::ptr::null_mut();
if WIN32_ERROR(WlanEnumInterfaces(w_handle, None, &mut wlan_interface_info_list)) != ERROR_SUCCESS {
  return;
}

for i in 0..wlan_interface_info_list.as_ref().unwrap().dwNumberOfItems {
  let interface_info = wlan_interface_info_list.as_ref().unwrap().InterfaceInfo[i as usize];
  let interface_name = interface_info.strInterfaceDescription;

  let mut available_network_list = std::mem::zeroed();
  if WIN32_ERROR(WlanGetAvailableNetworkList(w_handle, &interface_info.InterfaceGuid, 0, None, &mut available_network_list)) != ERROR_SUCCESS {
    continue;
  }

  let list = available_network_list.as_ref().unwrap();
  println!("Number of available networks on {}: {}", String::from_utf16_lossy(&interface_name), list.dwNumberOfItems);

  for j in 0..list.dwNumberOfItems {
    let network_name = (*list).Network[j as usize].strProfileName; // <- Panicked
    println!("Network name: {}", String::from_utf16_lossy(&network_name));
  }
}

WlanCloseHandle(w_handle, None);

Win32 API绑定中，WLAN_AVAILABLE_NETWORK_LIST结构体的Network字段被声明为[WLAN_AVAILABLE_NETWORK; 1]，这是C语言可变长度数组的常见Rust表示方式——仅标记数组的起始位置，而非实际长度。Rust会将其视为固定长度为1的数组，所以直接用索引访问j >=1的位置会触发越界错误。

需要将Network字段的起始指针转换为对应长度的Rust切片，再进行遍历，同时别忘了释放WlanGetAvailableNetworkList返回的内存（否则会造成内存泄漏）。

修改后的完整代码：

let mut w_handle: HANDLE = HANDLE::default();
let mut current_version: u32 = 0;

if WIN32_ERROR(WlanOpenHandle(2, None, &mut current_version, &mut w_handle)) != ERROR_SUCCESS {
  return;
}

let mut wlan_interface_info_list = std::ptr::null_mut();
if WIN32_ERROR(WlanEnumInterfaces(w_handle, None, &mut wlan_interface_info_list)) != ERROR_SUCCESS {
  return;
}

for i in 0..wlan_interface_info_list.as_ref().unwrap().dwNumberOfItems {
  let interface_info = wlan_interface_info_list.as_ref().unwrap().InterfaceInfo[i as usize];
  let interface_name = interface_info.strInterfaceDescription;

  let mut available_network_list = std::mem::zeroed();
  if WIN32_ERROR(WlanGetAvailableNetworkList(w_handle, &interface_info.InterfaceGuid, 0, None, &mut available_network_list)) != ERROR_SUCCESS {
    continue;
  }

  let list = available_network_list.as_ref().unwrap();
  println!("Number of available networks on {}: {}", String::from_utf16_lossy(&interface_name), list.dwNumberOfItems);

  // 将Network指针转换为指定长度的切片
  let networks = unsafe {
      std::slice::from_raw_parts(list.Network.as_ptr(), list.dwNumberOfItems as usize)
  };

  // 遍历切片获取所有网络
  for network in networks {
      let network_name = network.strProfileName;
      println!("Network name: {}", String::from_utf16_lossy(&network_name));
  }

  // 释放WlanGetAvailableNetworkList返回的内存
  unsafe {
      WlanFreeMemory(available_network_list as *mut _);
  }
}

// 释放WlanEnumInterfaces返回的接口列表内存
unsafe {
    WlanFreeMemory(wlan_interface_info_list as *mut _);
}

WlanCloseHandle(w_handle, None);

注：原代码遗漏了WlanEnumInterfaces返回列表的内存释放，已补充，避免内存泄漏。

内容的提问来源于stack exchange，提问作者ymgpwcca