arceos_posix_api/imp/
fd_ops.rs

1use alloc::sync::Arc;
2use core::ffi::c_int;
3
4use axerrno::{LinuxError, LinuxResult};
5use axio::PollState;
6use axns::{ResArc, def_resource};
7use flatten_objects::FlattenObjects;
8use spin::RwLock;
9
10use crate::ctypes;
11use crate::imp::stdio::{stdin, stdout};
12
13pub const AX_FILE_LIMIT: usize = 1024;
14
15#[allow(dead_code)]
16pub trait FileLike: Send + Sync {
17    fn read(&self, buf: &mut [u8]) -> LinuxResult<usize>;
18    fn write(&self, buf: &[u8]) -> LinuxResult<usize>;
19    fn stat(&self) -> LinuxResult<ctypes::stat>;
20    fn into_any(self: Arc<Self>) -> Arc<dyn core::any::Any + Send + Sync>;
21    fn poll(&self) -> LinuxResult<PollState>;
22    fn set_nonblocking(&self, nonblocking: bool) -> LinuxResult;
23}
24
25def_resource! {
26    pub(crate) static FD_TABLE: ResArc<RwLock<FlattenObjects<Arc<dyn FileLike>, AX_FILE_LIMIT>>> = ResArc::new();
27}
28
29pub fn get_file_like(fd: c_int) -> LinuxResult<Arc<dyn FileLike>> {
30    FD_TABLE
31        .read()
32        .get(fd as usize)
33        .cloned()
34        .ok_or(LinuxError::EBADF)
35}
36
37pub fn add_file_like(f: Arc<dyn FileLike>) -> LinuxResult<c_int> {
38    Ok(FD_TABLE.write().add(f).map_err(|_| LinuxError::EMFILE)? as c_int)
39}
40
41pub fn close_file_like(fd: c_int) -> LinuxResult {
42    let f = FD_TABLE
43        .write()
44        .remove(fd as usize)
45        .ok_or(LinuxError::EBADF)?;
46    drop(f);
47    Ok(())
48}
49
50/// Close a file by `fd`.
51pub fn sys_close(fd: c_int) -> c_int {
52    debug!("sys_close <= {}", fd);
53    if (0..=2).contains(&fd) {
54        return 0; // stdin, stdout, stderr
55    }
56    syscall_body!(sys_close, close_file_like(fd).map(|_| 0))
57}
58
59fn dup_fd(old_fd: c_int) -> LinuxResult<c_int> {
60    let f = get_file_like(old_fd)?;
61    let new_fd = add_file_like(f)?;
62    Ok(new_fd)
63}
64
65/// Duplicate a file descriptor.
66pub fn sys_dup(old_fd: c_int) -> c_int {
67    debug!("sys_dup <= {}", old_fd);
68    syscall_body!(sys_dup, dup_fd(old_fd))
69}
70
71/// Duplicate a file descriptor, but it uses the file descriptor number specified in `new_fd`.
72///
73/// TODO: `dup2` should forcibly close new_fd if it is already opened.
74pub fn sys_dup2(old_fd: c_int, new_fd: c_int) -> c_int {
75    debug!("sys_dup2 <= old_fd: {}, new_fd: {}", old_fd, new_fd);
76    syscall_body!(sys_dup2, {
77        if old_fd == new_fd {
78            let r = sys_fcntl(old_fd, ctypes::F_GETFD as _, 0);
79            if r >= 0 {
80                return Ok(old_fd);
81            } else {
82                return Ok(r);
83            }
84        }
85        if new_fd as usize >= AX_FILE_LIMIT {
86            return Err(LinuxError::EBADF);
87        }
88
89        let f = get_file_like(old_fd)?;
90        FD_TABLE
91            .write()
92            .add_at(new_fd as usize, f)
93            .map_err(|_| LinuxError::EMFILE)?;
94
95        Ok(new_fd)
96    })
97}
98
99/// Manipulate file descriptor.
100///
101/// TODO: `SET/GET` command is ignored, hard-code stdin/stdout
102pub fn sys_fcntl(fd: c_int, cmd: c_int, arg: usize) -> c_int {
103    debug!("sys_fcntl <= fd: {} cmd: {} arg: {}", fd, cmd, arg);
104    syscall_body!(sys_fcntl, {
105        match cmd as u32 {
106            ctypes::F_DUPFD => dup_fd(fd),
107            ctypes::F_DUPFD_CLOEXEC => {
108                // TODO: Change fd flags
109                dup_fd(fd)
110            }
111            ctypes::F_SETFL => {
112                if fd == 0 || fd == 1 || fd == 2 {
113                    return Ok(0);
114                }
115                get_file_like(fd)?.set_nonblocking(arg & (ctypes::O_NONBLOCK as usize) > 0)?;
116                Ok(0)
117            }
118            _ => {
119                warn!("unsupported fcntl parameters: cmd {}", cmd);
120                Ok(0)
121            }
122        }
123    })
124}
125
126#[ctor_bare::register_ctor]
127fn init_stdio() {
128    let mut fd_table = flatten_objects::FlattenObjects::new();
129    fd_table
130        .add_at(0, Arc::new(stdin()) as _)
131        .unwrap_or_else(|_| panic!()); // stdin
132    fd_table
133        .add_at(1, Arc::new(stdout()) as _)
134        .unwrap_or_else(|_| panic!()); // stdout
135    fd_table
136        .add_at(2, Arc::new(stdout()) as _)
137        .unwrap_or_else(|_| panic!()); // stderr
138    FD_TABLE.init_new(spin::RwLock::new(fd_table));
139}
arceos_posix_api/imp/fd_ops.rs

arceos_posix_api/imp/
fd_ops.rs
