906 lines
30 KiB
Rust
906 lines
30 KiB
Rust
use core::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
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use alloc::{string::String, sync::Arc, vec::Vec};
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use log::error;
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use system_error::SystemError;
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use super::{FileType, IndexNode, InodeId, Metadata, SpecialNodeData};
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use crate::process::pid::PidPrivateData;
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use crate::{
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driver::{
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base::{block::SeekFrom, device::DevicePrivateData},
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tty::tty_device::TtyFilePrivateData,
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},
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filesystem::{
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epoll::{event_poll::EPollPrivateData, EPollItem},
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procfs::ProcfsFilePrivateData,
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vfs::FilldirContext,
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},
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ipc::{kill::kill_process, pipe::PipeFsPrivateData},
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libs::{rwlock::RwLock, spinlock::SpinLock},
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process::{cred::Cred, resource::RLimitID, ProcessControlBlock, ProcessManager, RawPid},
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};
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const MAX_LFS_FILESIZE: i64 = i64::MAX;
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/// 文件私有信息的枚举类型
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#[derive(Debug, Clone)]
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#[allow(dead_code)]
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pub enum FilePrivateData {
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/// 管道文件私有信息
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Pipefs(PipeFsPrivateData),
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/// procfs文件私有信息
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Procfs(ProcfsFilePrivateData),
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/// 设备文件的私有信息
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DevFS(DevicePrivateData),
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/// tty设备文件的私有信息
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Tty(TtyFilePrivateData),
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/// epoll私有信息
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EPoll(EPollPrivateData),
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/// pid私有信息
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Pid(PidPrivateData),
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/// 不需要文件私有信息
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Unused,
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}
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impl Default for FilePrivateData {
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fn default() -> Self {
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return Self::Unused;
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}
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}
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impl FilePrivateData {
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pub fn update_mode(&mut self, mode: FileMode) {
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if let FilePrivateData::Pipefs(pdata) = self {
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pdata.set_mode(mode);
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}
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}
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pub fn is_pid(&self) -> bool {
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if let FilePrivateData::Pid(_data) = self {
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return true;
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}
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false
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}
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pub fn get_pid(&self) -> i32 {
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if let FilePrivateData::Pid(data) = self {
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return data.pid();
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}
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-1
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}
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}
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bitflags! {
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/// @brief 文件打开模式
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/// 其中，低2bit组合而成的数字的值，用于表示访问权限。其他的bit，才支持通过按位或的方式来表示参数
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///
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/// 与Linux 5.19.10的uapi/asm-generic/fcntl.h相同
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/// https://code.dragonos.org.cn/xref/linux-5.19.10/tools/include/uapi/asm-generic/fcntl.h#19
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#[allow(clippy::bad_bit_mask)]
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pub struct FileMode: u32{
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/* File access modes for `open' and `fcntl'. */
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/// Open Read-only
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const O_RDONLY = 0o0;
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/// Open Write-only
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const O_WRONLY = 0o1;
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/// Open read/write
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const O_RDWR = 0o2;
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/// Mask for file access modes
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const O_ACCMODE = 0o00000003;
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/* Bits OR'd into the second argument to open. */
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/// Create file if it does not exist
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const O_CREAT = 0o00000100;
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/// Fail if file already exists
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const O_EXCL = 0o00000200;
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/// Do not assign controlling terminal
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const O_NOCTTY = 0o00000400;
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/// 文件存在且是普通文件，并以O_RDWR或O_WRONLY打开，则它会被清空
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const O_TRUNC = 0o00001000;
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/// 文件指针会被移动到文件末尾
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const O_APPEND = 0o00002000;
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/// 非阻塞式IO模式
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const O_NONBLOCK = 0o00004000;
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/// 每次write都等待物理I/O完成，但是如果写操作不影响读取刚写入的数据，则不等待文件属性更新
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const O_DSYNC = 0o00010000;
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/// fcntl, for BSD compatibility
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const FASYNC = 0o00020000;
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/* direct disk access hint */
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const O_DIRECT = 0o00040000;
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const O_LARGEFILE = 0o00100000;
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/// 打开的必须是一个目录
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const O_DIRECTORY = 0o00200000;
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/// Do not follow symbolic links
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const O_NOFOLLOW = 0o00400000;
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const O_NOATIME = 0o01000000;
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/// set close_on_exec
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const O_CLOEXEC = 0o02000000;
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/// 每次write都等到物理I/O完成，包括write引起的文件属性的更新
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const O_SYNC = 0o04000000;
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const O_PATH = 0o10000000;
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const O_PATH_FLAGS = Self::O_DIRECTORY.bits|Self::O_NOFOLLOW.bits|Self::O_CLOEXEC.bits|Self::O_PATH.bits;
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}
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}
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impl FileMode {
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/// @brief 获取文件的访问模式的值
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#[inline]
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pub fn accmode(&self) -> u32 {
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return self.bits() & FileMode::O_ACCMODE.bits();
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}
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}
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/// @brief 抽象文件结构体
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#[derive(Debug)]
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pub struct File {
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inode: Arc<dyn IndexNode>,
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/// 对于文件，表示字节偏移量；对于文件夹，表示当前操作的子目录项偏移量
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offset: AtomicUsize,
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/// 文件的打开模式
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mode: RwLock<FileMode>,
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/// 文件类型
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file_type: FileType,
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/// readdir时候用的，暂存的本次循环中，所有子目录项的名字的数组
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readdir_subdirs_name: SpinLock<Vec<String>>,
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pub private_data: SpinLock<FilePrivateData>,
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/// 文件的凭证
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cred: Arc<Cred>,
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/// 文件描述符标志：是否在execve时关闭
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close_on_exec: AtomicBool,
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/// owner
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pid: SpinLock<Option<Arc<ProcessControlBlock>>>,
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}
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impl File {
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/// @brief 创建一个新的文件对象
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///
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/// @param inode 文件对象对应的inode
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/// @param mode 文件的打开模式
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pub fn new(inode: Arc<dyn IndexNode>, mut mode: FileMode) -> Result<Self, SystemError> {
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let mut inode = inode;
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let file_type = inode.metadata()?.file_type;
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if file_type == FileType::Pipe {
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if let Some(SpecialNodeData::Pipe(pipe_inode)) = inode.special_node() {
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inode = pipe_inode;
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}
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}
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let close_on_exec = mode.contains(FileMode::O_CLOEXEC);
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mode.remove(FileMode::O_CLOEXEC);
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let private_data = SpinLock::new(FilePrivateData::default());
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inode.open(private_data.lock(), &mode)?;
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let f = File {
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inode,
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offset: AtomicUsize::new(0),
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mode: RwLock::new(mode),
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file_type,
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readdir_subdirs_name: SpinLock::new(Vec::default()),
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private_data,
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cred: ProcessManager::current_pcb().cred(),
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close_on_exec: AtomicBool::new(close_on_exec),
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pid: SpinLock::new(None),
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};
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return Ok(f);
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}
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/// ## 从文件中读取指定的字节数到buffer中
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///
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/// ### 参数
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/// - `len`: 要读取的字节数
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/// - `buf`: 缓冲区
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/// - `read_direct`: 忽略缓存，直接读取磁盘
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///
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/// ### 返回值
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/// - `Ok(usize)`: 成功读取的字节数
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/// - `Err(SystemError)`: 错误码
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pub fn read(&self, len: usize, buf: &mut [u8]) -> Result<usize, SystemError> {
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self.do_read(
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self.offset.load(core::sync::atomic::Ordering::SeqCst),
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len,
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buf,
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true,
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)
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}
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/// ## 从buffer向文件写入指定的字节数的数据
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///
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/// ### 参数
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/// - `offset`: 文件偏移量
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/// - `len`: 要写入的字节数
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/// - `buf`: 写入缓冲区
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///
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/// ### 返回值
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/// - `Ok(usize)`: 成功写入的字节数
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/// - `Err(SystemError)`: 错误码
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pub fn write(&self, len: usize, buf: &[u8]) -> Result<usize, SystemError> {
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self.do_write(
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self.offset.load(core::sync::atomic::Ordering::SeqCst),
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len,
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buf,
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true,
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)
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}
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/// ## 从文件中指定的偏移处读取指定的字节数到buf中
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///
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/// ### 参数
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/// - `offset`: 文件偏移量
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/// - `len`: 要读取的字节数
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/// - `buf`: 读出缓冲区
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///
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/// ### 返回值
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/// - `Ok(usize)`: 成功读取的字节数
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pub fn pread(&self, offset: usize, len: usize, buf: &mut [u8]) -> Result<usize, SystemError> {
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self.do_read(offset, len, buf, false)
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}
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/// ## 从buf向文件中指定的偏移处写入指定的字节数的数据
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///
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/// ### 参数
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/// - `offset`: 文件偏移量
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/// - `len`: 要写入的字节数
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/// - `buf`: 写入缓冲区
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///
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/// ### 返回值
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/// - `Ok(usize)`: 成功写入的字节数
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pub fn pwrite(&self, offset: usize, len: usize, buf: &[u8]) -> Result<usize, SystemError> {
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self.do_write(offset, len, buf, false)
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}
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pub fn do_read(
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&self,
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offset: usize,
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len: usize,
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buf: &mut [u8],
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update_offset: bool,
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) -> Result<usize, SystemError> {
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// 先检查本文件在权限等规则下，是否可读取。
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self.readable()?;
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if buf.len() < len {
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return Err(SystemError::ENOBUFS);
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}
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let len = if self.mode().contains(FileMode::O_DIRECT) {
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self.inode
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.read_direct(offset, len, buf, self.private_data.lock())
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} else {
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self.inode
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.read_at(offset, len, buf, self.private_data.lock())
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}?;
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if update_offset {
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self.offset
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.fetch_add(len, core::sync::atomic::Ordering::SeqCst);
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}
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Ok(len)
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}
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pub fn do_write(
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&self,
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offset: usize,
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len: usize,
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buf: &[u8],
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update_offset: bool,
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) -> Result<usize, SystemError> {
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// 先检查本文件在权限等规则下，是否可写入。
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self.writeable()?;
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if buf.len() < len {
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return Err(SystemError::ENOBUFS);
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}
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// 获取文件类型
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let md = self.inode.metadata()?;
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let file_type = md.file_type;
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// 检查RLIMIT_FSIZE限制（仅对常规文件生效）
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let actual_len = if matches!(file_type, FileType::File) {
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let current_pcb = ProcessManager::current_pcb();
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let fsize_limit = current_pcb.get_rlimit(RLimitID::Fsize);
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if fsize_limit.rlim_cur != u64::MAX {
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let limit = fsize_limit.rlim_cur as usize;
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// 如果当前文件大小已经达到或超过限制，不允许写入
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if offset >= limit {
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// 发送SIGXFSZ信号
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let _ = kill_process(
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current_pcb.raw_pid(),
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crate::arch::ipc::signal::Signal::SIGXFSZ,
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);
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return Err(SystemError::EFBIG);
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}
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// 计算可写入的最大长度（不超过限制）
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let max_writable = limit.saturating_sub(offset);
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if len > max_writable {
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max_writable
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} else {
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len
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}
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} else {
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len
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}
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} else {
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len
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};
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// 仅常规文件考虑“指针超过大小则扩展”语义；管道/字符设备等不应触发 resize
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if matches!(file_type, FileType::File) && offset > md.size as usize {
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self.inode.resize(offset)?;
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}
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let written_len = self
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.inode
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.write_at(offset, actual_len, buf, self.private_data.lock())?;
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if update_offset {
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self.offset
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.fetch_add(written_len, core::sync::atomic::Ordering::SeqCst);
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}
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Ok(written_len)
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}
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/// @brief 获取文件的元数据
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pub fn metadata(&self) -> Result<Metadata, SystemError> {
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return self.inode.metadata();
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}
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/// @brief 根据inode号获取子目录项的名字
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#[allow(dead_code)]
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pub fn get_entry_name(&self, ino: InodeId) -> Result<String, SystemError> {
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return self.inode.get_entry_name(ino);
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}
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/// @brief 调整文件操作指针的位置
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///
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/// @param origin 调整的起始位置
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pub fn lseek(&self, origin: SeekFrom) -> Result<usize, SystemError> {
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let file_type = self.inode.metadata()?.file_type;
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match file_type {
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FileType::Pipe | FileType::CharDevice => {
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return Err(SystemError::ESPIPE);
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}
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_ => {}
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}
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// Check for procfs private data. If this is a procfs pseudo-file, disallow SEEK_END
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// and other unsupported seek modes.
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{
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let pdata = self.private_data.lock();
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if let FilePrivateData::Procfs(_) = &*pdata {
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match origin {
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SeekFrom::SeekEnd(_) | SeekFrom::Invalid => {
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return Err(SystemError::EINVAL);
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}
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_ => {}
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}
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}
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}
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let pos: i64 = match origin {
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SeekFrom::SeekSet(offset) => offset,
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SeekFrom::SeekCurrent(offset) => self.offset.load(Ordering::SeqCst) as i64 + offset,
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SeekFrom::SeekEnd(offset) => {
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if FileType::Dir == file_type {
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// 对目录，返回 Linux 常见语义：允许 SEEK_END 并返回 MAX_LFS_FILESIZE。
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// 测试接受 MAX_LFS_FILESIZE 或 EINVAL，但为通过当前测试选择返回 MAX_LFS_FILESIZE。
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return Ok(MAX_LFS_FILESIZE as usize);
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}
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let metadata = self.metadata()?;
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metadata.size + offset
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}
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SeekFrom::Invalid => {
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return Err(SystemError::EINVAL);
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}
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};
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// 根据linux man page, lseek允许超出文件末尾，并且不改变文件大小
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// 当pos超出文件末尾时，read返回0。直到开始写入数据时，才会改变文件大小
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if pos < 0 {
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return Err(SystemError::EINVAL);
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}
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self.offset.store(pos as usize, Ordering::SeqCst);
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return Ok(pos as usize);
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}
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/// @brief 判断当前文件是否可读
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#[inline]
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pub fn readable(&self) -> Result<(), SystemError> {
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let mode = *self.mode.read();
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// 暂时认为只要不是write only, 就可读
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if mode == FileMode::O_WRONLY || mode.contains(FileMode::O_PATH) {
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return Err(SystemError::EBADF);
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}
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return Ok(());
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}
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/// @brief 判断当前文件是否可写
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#[inline]
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pub fn writeable(&self) -> Result<(), SystemError> {
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let mode = *self.mode.read();
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// 检查是否是O_PATH文件描述符
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if mode.contains(FileMode::O_PATH) {
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return Err(SystemError::EBADF);
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}
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// 暂时认为只要不是read only, 就可写
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if mode == FileMode::O_RDONLY {
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return Err(SystemError::EPERM);
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}
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return Ok(());
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}
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/// # 读取目录项
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///
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/// ## 参数
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/// - ctx 填充目录项的上下文
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pub fn read_dir(&self, ctx: &mut FilldirContext) -> Result<(), SystemError> {
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// O_PATH 文件描述符只能用于有限的操作，getdents/getdents64
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// 在 Linux 中会返回 EBADF。提前检测并返回相同语义。
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if self.mode().contains(FileMode::O_PATH) {
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return Err(SystemError::EBADF);
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}
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// 仅目录允许读取目录项，其它类型遵循 POSIX 语义返回 ENOTDIR。
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if self.file_type() != FileType::Dir {
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return Err(SystemError::ENOTDIR);
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}
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let inode: &Arc<dyn IndexNode> = &self.inode;
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let mut current_pos = self.offset.load(Ordering::SeqCst);
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// POSIX 标准要求readdir应该返回. 和 ..
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// 但是观察到在现有的子目录中已经包含，不做处理也能正常返回. 和 .. 这里先不做处理
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// 迭代读取目录项
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// 为了保证在目录内容动态变化（例如 /proc/self/fd）时不会因为重新
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// 创建列表而丢失尚未读取的目录项，这里缓存第一次生成的列表，在
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// 文件偏移被 seek 到 0 之前复用该缓存。
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let mut cached_names = self.readdir_subdirs_name.lock();
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if current_pos == 0 || cached_names.is_empty() {
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||
*cached_names = inode.list()?;
|
||
}
|
||
let readdir_subdirs_name = cached_names.clone();
|
||
drop(cached_names);
|
||
|
||
let subdirs_name_len = readdir_subdirs_name.len();
|
||
while current_pos < subdirs_name_len {
|
||
let name = &readdir_subdirs_name[current_pos];
|
||
let sub_inode: Arc<dyn IndexNode> = match inode.find(name) {
|
||
Ok(i) => i,
|
||
Err(e) => {
|
||
if e == SystemError::ENOENT {
|
||
// 目录项在本次读取过程中被移除，跳过它，继续读取后续条目
|
||
self.offset.fetch_add(1, Ordering::SeqCst);
|
||
current_pos += 1;
|
||
continue;
|
||
}
|
||
error!("Readdir error: Failed to find sub inode");
|
||
return Err(e);
|
||
}
|
||
};
|
||
|
||
let inode_metadata = sub_inode.metadata().unwrap();
|
||
let entry_ino = inode_metadata.inode_id.into() as u64;
|
||
let entry_d_type = inode_metadata.file_type.get_file_type_num() as u8;
|
||
match ctx.fill_dir(name, current_pos, entry_ino, entry_d_type) {
|
||
Ok(_) => {
|
||
self.offset.fetch_add(1, Ordering::SeqCst);
|
||
current_pos += 1;
|
||
}
|
||
Err(SystemError::EINVAL) => {
|
||
return Ok(());
|
||
}
|
||
Err(e) => {
|
||
ctx.error = Some(e.clone());
|
||
return Err(e);
|
||
}
|
||
}
|
||
}
|
||
return Ok(());
|
||
}
|
||
|
||
pub fn inode(&self) -> Arc<dyn IndexNode> {
|
||
return self.inode.clone();
|
||
}
|
||
|
||
/// @brief 尝试克隆一个文件
|
||
///
|
||
/// @return Option<File> 克隆后的文件结构体。如果克隆失败，返回None
|
||
pub fn try_clone(&self) -> Option<File> {
|
||
let res = Self {
|
||
inode: self.inode.clone(),
|
||
offset: AtomicUsize::new(self.offset.load(Ordering::SeqCst)),
|
||
mode: RwLock::new(self.mode()),
|
||
file_type: self.file_type,
|
||
readdir_subdirs_name: SpinLock::new(self.readdir_subdirs_name.lock().clone()),
|
||
private_data: SpinLock::new(self.private_data.lock().clone()),
|
||
cred: self.cred.clone(),
|
||
close_on_exec: AtomicBool::new(self.close_on_exec.load(Ordering::SeqCst)),
|
||
pid: SpinLock::new(None),
|
||
};
|
||
// 调用inode的open方法，让inode知道有新的文件打开了这个inode
|
||
// TODO: reopen is not a good idea for some inodes, need a better design
|
||
if self
|
||
.inode
|
||
.open(res.private_data.lock(), &res.mode())
|
||
.is_err()
|
||
{
|
||
return None;
|
||
}
|
||
|
||
return Some(res);
|
||
}
|
||
|
||
/// @brief 获取文件的类型
|
||
#[inline]
|
||
pub fn file_type(&self) -> FileType {
|
||
return self.file_type;
|
||
}
|
||
|
||
/// @brief 获取文件的打开模式
|
||
#[inline]
|
||
pub fn mode(&self) -> FileMode {
|
||
return *self.mode.read();
|
||
}
|
||
|
||
/// 获取文件是否在execve时关闭
|
||
#[inline]
|
||
pub fn close_on_exec(&self) -> bool {
|
||
return self.close_on_exec.load(Ordering::SeqCst);
|
||
}
|
||
|
||
/// 设置文件是否在execve时关闭
|
||
#[inline]
|
||
pub fn set_close_on_exec(&self, close_on_exec: bool) {
|
||
self.close_on_exec.store(close_on_exec, Ordering::SeqCst);
|
||
}
|
||
|
||
pub fn set_mode(&self, mut mode: FileMode) -> Result<(), SystemError> {
|
||
// todo: 是否需要调用inode的open方法，以更新private data（假如它与mode有关的话）?
|
||
// 也许需要加个更好的设计，让inode知晓文件的打开模式发生了变化，让它自己决定是否需要更新private data
|
||
|
||
// 提取 O_CLOEXEC 状态并更新 close_on_exec 字段
|
||
let close_on_exec = mode.contains(FileMode::O_CLOEXEC);
|
||
self.close_on_exec.store(close_on_exec, Ordering::SeqCst);
|
||
|
||
// 从 mode 中移除 O_CLOEXEC 标志，保持与构造函数一致的行为
|
||
mode.remove(FileMode::O_CLOEXEC);
|
||
|
||
// 更新文件的打开模式
|
||
*self.mode.write() = mode;
|
||
self.private_data.lock().update_mode(mode);
|
||
return Ok(());
|
||
}
|
||
|
||
/// @brief 重新设置文件的大小
|
||
///
|
||
/// 如果文件大小增加，则文件内容不变，但是文件的空洞部分会被填充为0
|
||
/// 如果文件大小减小，则文件内容会被截断
|
||
///
|
||
/// @return 成功：Ok()
|
||
/// 失败：Err(错误码)
|
||
pub fn ftruncate(&self, len: usize) -> Result<(), SystemError> {
|
||
// 如果文件不可写，返回错误
|
||
self.writeable()?;
|
||
|
||
// 统一通过 VFS 封装，复用类型/只读检查
|
||
crate::filesystem::vfs::vcore::vfs_truncate(self.inode(), len)?;
|
||
return Ok(());
|
||
}
|
||
|
||
/// Add an EPollItem to the file
|
||
pub fn add_epitem(&self, epitem: Arc<EPollItem>) -> Result<(), SystemError> {
|
||
let private_data = self.private_data.lock();
|
||
self.inode
|
||
.as_pollable_inode()?
|
||
.add_epitem(epitem, &private_data)
|
||
}
|
||
|
||
/// Remove epitems associated with the epoll
|
||
pub fn remove_epitem(&self, epitem: &Arc<EPollItem>) -> Result<(), SystemError> {
|
||
let private_data = self.private_data.lock();
|
||
self.inode
|
||
.as_pollable_inode()?
|
||
.remove_epitem(epitem, &private_data)
|
||
}
|
||
|
||
/// Poll the file for events
|
||
pub fn poll(&self) -> Result<usize, SystemError> {
|
||
let private_data = self.private_data.lock();
|
||
self.inode.as_pollable_inode()?.poll(&private_data)
|
||
}
|
||
|
||
pub fn owner(&self) -> Option<RawPid> {
|
||
self.pid.lock().as_ref().map(|pcb| pcb.raw_pid())
|
||
}
|
||
|
||
/// Set a process (group) as owner of the file descriptor.
|
||
///
|
||
/// Such that this process (group) will receive `SIGIO` and `SIGURG` signals
|
||
/// for I/O events on the file descriptor, if `O_ASYNC` status flag is set
|
||
/// on this file.
|
||
pub fn set_owner(&self, pid: Option<Arc<ProcessControlBlock>>) -> Result<(), SystemError> {
|
||
let Some(pcb) = pid else {
|
||
*self.pid.lock() = None;
|
||
return Ok(());
|
||
};
|
||
|
||
self.pid.lock().replace(pcb);
|
||
// todo: update inode owner
|
||
log::error!("set_owner has not been implemented yet");
|
||
Ok(())
|
||
}
|
||
}
|
||
|
||
impl Drop for File {
|
||
fn drop(&mut self) {
|
||
let r: Result<(), SystemError> = self.inode.close(self.private_data.lock());
|
||
// 打印错误信息
|
||
if r.is_err() {
|
||
error!(
|
||
"pid: {:?} failed to close file: {:?}, errno={:?}",
|
||
ProcessManager::current_pcb().raw_pid(),
|
||
self,
|
||
r.as_ref().unwrap_err()
|
||
);
|
||
}
|
||
}
|
||
}
|
||
|
||
/// @brief pcb里面的文件描述符数组
|
||
#[derive(Debug)]
|
||
pub struct FileDescriptorVec {
|
||
/// 当前进程打开的文件描述符
|
||
fds: Vec<Option<Arc<File>>>,
|
||
}
|
||
impl Default for FileDescriptorVec {
|
||
fn default() -> Self {
|
||
Self::new()
|
||
}
|
||
}
|
||
impl FileDescriptorVec {
|
||
/// 文件描述符表的初始容量
|
||
pub const INITIAL_CAPACITY: usize = 1024;
|
||
/// 文件描述符表的最大容量限制（防止无限扩容）
|
||
pub const MAX_CAPACITY: usize = 65536;
|
||
|
||
#[inline(never)]
|
||
pub fn new() -> FileDescriptorVec {
|
||
let mut data = Vec::with_capacity(FileDescriptorVec::INITIAL_CAPACITY);
|
||
data.resize(FileDescriptorVec::INITIAL_CAPACITY, None);
|
||
|
||
// 初始化文件描述符数组结构体
|
||
return FileDescriptorVec { fds: data };
|
||
}
|
||
|
||
/// @brief 克隆一个文件描述符数组
|
||
///
|
||
/// @return FileDescriptorVec 克隆后的文件描述符数组
|
||
pub fn clone(&self) -> FileDescriptorVec {
|
||
let mut res = FileDescriptorVec::new();
|
||
// 调整容量以匹配源文件描述符表
|
||
let _ = res.resize_to_capacity(self.fds.len());
|
||
|
||
for i in 0..self.fds.len() {
|
||
if let Some(file) = &self.fds[i] {
|
||
res.fds[i] = Some(file.clone());
|
||
}
|
||
}
|
||
return res;
|
||
}
|
||
|
||
/// 返回当前已占用的最高文件描述符索引（若无则为None）
|
||
#[inline]
|
||
fn highest_open_index(&self) -> Option<usize> {
|
||
// 从高到低查找第一个占用的槽位
|
||
(0..self.fds.len()).rev().find(|&i| self.fds[i].is_some())
|
||
}
|
||
|
||
/// 扩容文件描述符表到指定容量
|
||
///
|
||
/// ## 参数
|
||
/// - `new_capacity`: 新的容量大小
|
||
///
|
||
/// ## 返回值
|
||
/// - `Ok(())`: 扩容成功
|
||
/// - `Err(SystemError)`: 扩容失败
|
||
fn resize_to_capacity(&mut self, new_capacity: usize) -> Result<(), SystemError> {
|
||
if new_capacity > FileDescriptorVec::MAX_CAPACITY {
|
||
return Err(SystemError::EMFILE);
|
||
}
|
||
|
||
let current_len = self.fds.len();
|
||
if new_capacity > current_len {
|
||
// 扩容：扩展向量并填充None
|
||
// 使用 try_reserve 先检查内存分配是否可能成功
|
||
if self.fds.try_reserve(new_capacity - current_len).is_err() {
|
||
return Err(SystemError::ENOMEM);
|
||
}
|
||
self.fds.resize(new_capacity, None);
|
||
} else if new_capacity < current_len {
|
||
// 缩容：允许，但不能丢弃仍在使用的高位fd。
|
||
// 若高位fd仍在使用，将缩容目标提升到 (最高已用fd + 1)。
|
||
let floor = self.highest_open_index().map(|idx| idx + 1).unwrap_or(0);
|
||
let target = core::cmp::max(new_capacity, floor);
|
||
if target < current_len {
|
||
self.fds.truncate(target);
|
||
}
|
||
}
|
||
Ok(())
|
||
}
|
||
|
||
/// 返回 `已经打开的` 文件描述符的数量
|
||
pub fn fd_open_count(&self) -> usize {
|
||
let mut size = 0;
|
||
for fd in &self.fds {
|
||
if fd.is_some() {
|
||
size += 1;
|
||
}
|
||
}
|
||
return size;
|
||
}
|
||
|
||
/// @brief 判断文件描述符序号是否合法
|
||
///
|
||
/// @return true 合法
|
||
///
|
||
/// @return false 不合法
|
||
#[inline]
|
||
pub fn validate_fd(&self, fd: i32) -> bool {
|
||
return !(fd < 0 || fd as usize >= self.fds.len());
|
||
}
|
||
|
||
/// 申请文件描述符，并把文件对象存入其中。
|
||
///
|
||
/// ## 参数
|
||
///
|
||
/// - `file` 要存放的文件对象
|
||
/// - `fd` 如果为Some(i32)，表示指定要申请这个文件描述符，如果这个文件描述符已经被使用，那么返回EBADF
|
||
///
|
||
/// ## 返回值
|
||
///
|
||
/// - `Ok(i32)` 申请成功，返回申请到的文件描述符
|
||
/// - `Err(SystemError)` 申请失败，返回错误码，并且，file对象将被drop掉
|
||
pub fn alloc_fd(&mut self, file: File, fd: Option<i32>) -> Result<i32, SystemError> {
|
||
// 获取RLIMIT_NOFILE限制
|
||
let nofile_limit = crate::process::ProcessManager::current_pcb()
|
||
.get_rlimit(crate::process::resource::RLimitID::Nofile)
|
||
.rlim_cur as usize;
|
||
|
||
if let Some(new_fd) = fd {
|
||
// 检查指定的文件描述符是否在有效范围内
|
||
if new_fd < 0 || new_fd as usize >= nofile_limit {
|
||
return Err(SystemError::EMFILE);
|
||
}
|
||
|
||
// 如果指定的fd超出当前容量，需要扩容
|
||
if new_fd as usize >= self.fds.len() {
|
||
self.resize_to_capacity(new_fd as usize + 1)?;
|
||
}
|
||
|
||
let x = &mut self.fds[new_fd as usize];
|
||
if x.is_none() {
|
||
*x = Some(Arc::new(file));
|
||
return Ok(new_fd);
|
||
} else {
|
||
return Err(SystemError::EBADF);
|
||
}
|
||
} else {
|
||
// 没有指定要申请的文件描述符编号，在有效范围内查找空位
|
||
let max_search = core::cmp::min(self.fds.len(), nofile_limit);
|
||
for i in 0..max_search {
|
||
if self.fds[i].is_none() {
|
||
self.fds[i] = Some(Arc::new(file));
|
||
return Ok(i as i32);
|
||
}
|
||
}
|
||
return Err(SystemError::EMFILE);
|
||
}
|
||
}
|
||
|
||
/// 根据文件描述符序号，获取文件结构体的Arc指针
|
||
///
|
||
/// ## 参数
|
||
///
|
||
/// - `fd` 文件描述符序号
|
||
pub fn get_file_by_fd(&self, fd: i32) -> Option<Arc<File>> {
|
||
if !self.validate_fd(fd) {
|
||
return None;
|
||
}
|
||
self.fds[fd as usize].clone()
|
||
}
|
||
|
||
/// 当RLIMIT_NOFILE变化时调整文件描述符表容量
|
||
///
|
||
/// ## 参数
|
||
/// - `new_rlimit_nofile`: 新的RLIMIT_NOFILE值
|
||
///
|
||
/// ## 返回值
|
||
/// - `Ok(())`: 调整成功
|
||
/// - `Err(SystemError)`: 调整失败
|
||
pub fn adjust_for_rlimit_change(
|
||
&mut self,
|
||
new_rlimit_nofile: usize,
|
||
) -> Result<(), SystemError> {
|
||
// 目标容量不超过实现上限
|
||
let desired = core::cmp::min(new_rlimit_nofile, FileDescriptorVec::MAX_CAPACITY);
|
||
if desired >= self.fds.len() {
|
||
// rlimit 变大：扩容到 desired
|
||
self.resize_to_capacity(desired)
|
||
} else {
|
||
// rlimit 变小：按用户建议，缩容到 max(desired, 最高已用fd+1)
|
||
let floor = self.highest_open_index().map(|idx| idx + 1).unwrap_or(0);
|
||
let target = core::cmp::max(desired, floor);
|
||
self.resize_to_capacity(target)
|
||
}
|
||
}
|
||
|
||
/// 释放文件描述符，同时关闭文件。
|
||
///
|
||
/// ## 参数
|
||
///
|
||
/// - `fd` 文件描述符序号
|
||
pub fn drop_fd(&mut self, fd: i32) -> Result<Arc<File>, SystemError> {
|
||
self.get_file_by_fd(fd).ok_or(SystemError::EBADF)?;
|
||
|
||
// 把文件描述符数组对应位置设置为空
|
||
let file = self.fds[fd as usize].take().unwrap();
|
||
return Ok(file);
|
||
}
|
||
|
||
#[allow(dead_code)]
|
||
pub fn iter(&self) -> FileDescriptorIterator<'_> {
|
||
return FileDescriptorIterator::new(self);
|
||
}
|
||
|
||
pub fn close_on_exec(&mut self) {
|
||
for i in 0..self.fds.len() {
|
||
if let Some(file) = &self.fds[i] {
|
||
let to_drop = file.close_on_exec();
|
||
if to_drop {
|
||
if let Err(r) = self.drop_fd(i as i32) {
|
||
error!(
|
||
"Failed to close file: pid = {:?}, fd = {}, error = {:?}",
|
||
ProcessManager::current_pcb().raw_pid(),
|
||
i,
|
||
r
|
||
);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
#[derive(Debug)]
|
||
pub struct FileDescriptorIterator<'a> {
|
||
fds: &'a FileDescriptorVec,
|
||
index: usize,
|
||
}
|
||
|
||
impl<'a> FileDescriptorIterator<'a> {
|
||
pub fn new(fds: &'a FileDescriptorVec) -> Self {
|
||
return Self { fds, index: 0 };
|
||
}
|
||
}
|
||
|
||
impl Iterator for FileDescriptorIterator<'_> {
|
||
type Item = (i32, Arc<File>);
|
||
|
||
fn next(&mut self) -> Option<Self::Item> {
|
||
while self.index < self.fds.fds.len() {
|
||
let fd = self.index as i32;
|
||
self.index += 1;
|
||
if let Some(file) = self.fds.get_file_by_fd(fd) {
|
||
return Some((fd, file));
|
||
}
|
||
}
|
||
return None;
|
||
}
|
||
}
|