105 lines
3.1 KiB
Rust
105 lines
3.1 KiB
Rust
//! System call handler for sys_umount.
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use crate::{
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arch::{interrupt::TrapFrame, syscall::nr::SYS_UMOUNT2},
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filesystem::vfs::{
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fcntl::AtFlags, mount::MOUNT_LIST, utils::user_path_at, MountFS, MAX_PATHLEN,
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},
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process::ProcessManager,
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syscall::{
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table::{FormattedSyscallParam, Syscall},
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user_access,
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},
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};
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use alloc::{sync::Arc, vec::Vec};
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use system_error::SystemError;
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/// src/linux/mount.c `umount` & `umount2`
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///
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/// [umount(2) — Linux manual page](https://www.man7.org/linux/man-pages/man2/umount.2.html)
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pub struct SysUmount2Handle;
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impl Syscall for SysUmount2Handle {
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fn num_args(&self) -> usize {
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2
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}
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fn handle(&self, args: &[usize], _frame: &mut TrapFrame) -> Result<usize, SystemError> {
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let target = Self::target(args);
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let flags = Self::flags(args);
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let target = user_access::check_and_clone_cstr(target, Some(MAX_PATHLEN))?
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.into_string()
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.map_err(|_| SystemError::EINVAL)?;
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do_umount2(
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AtFlags::AT_FDCWD.bits(),
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&target,
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UmountFlag::from_bits(flags).ok_or(SystemError::EINVAL)?,
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)?;
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return Ok(0);
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}
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fn entry_format(&self, args: &[usize]) -> Vec<FormattedSyscallParam> {
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vec![
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FormattedSyscallParam::new("target", format!("{:#x}", Self::target(args) as usize)),
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FormattedSyscallParam::new("flags", format!("{:#x}", Self::flags(args))),
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]
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}
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}
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impl SysUmount2Handle {
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fn target(args: &[usize]) -> *const u8 {
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args[0] as *const u8
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}
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fn flags(args: &[usize]) -> i32 {
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args[1] as i32
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}
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}
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syscall_table_macros::declare_syscall!(SYS_UMOUNT2, SysUmount2Handle);
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/// # do_umount2 - 执行卸载文件系统的函数
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///
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/// 这个函数用于卸载指定的文件系统。
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///
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/// ## 参数
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///
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/// - dirfd: i32 - 目录文件描述符，用于指定要卸载的文件系统的根目录。
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/// - target: &str - 要卸载的文件系统的目标路径。
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/// - _flag: UmountFlag - 卸载标志，目前未使用。
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///
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/// ## 返回值
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///
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/// - Ok(Arc<MountFS>): 成功时返回文件系统的 Arc 引用。
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/// - Err(SystemError): 出错时返回系统错误。
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///
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/// ## 错误处理
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///
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/// 如果指定的路径没有对应的文件系统，或者在尝试卸载时发生错误，将返回错误。
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pub fn do_umount2(
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dirfd: i32,
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target: &str,
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_flag: UmountFlag,
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) -> Result<Arc<MountFS>, SystemError> {
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let (work, rest) = user_path_at(&ProcessManager::current_pcb(), dirfd, target)?;
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let path = work.absolute_path()? + &rest;
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if let Some(fs) = MOUNT_LIST().remove(path) {
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// Todo: 占用检测
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fs.umount()?;
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return Ok(fs);
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}
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return Err(SystemError::EINVAL);
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}
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bitflags! {
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pub struct UmountFlag: i32 {
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const DEFAULT = 0; /* Default call to umount. */
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const MNT_FORCE = 1; /* Force unmounting. */
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const MNT_DETACH = 2; /* Just detach from the tree. */
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const MNT_EXPIRE = 4; /* Mark for expiry. */
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const UMOUNT_NOFOLLOW = 8; /* Don't follow symlink on umount. */
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}
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}
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