redox/kernel/scheme/root.rs

104 lines
2.9 KiB
Rust

use alloc::arc::Arc;
use alloc::boxed::Box;
use collections::BTreeMap;
use core::sync::atomic::{AtomicUsize, ATOMIC_USIZE_INIT, Ordering};
use spin::RwLock;
use context;
use syscall::error::*;
use syscall::scheme::Scheme;
use scheme;
use scheme::user::{UserInner, UserScheme};
pub static ROOT_SCHEME_ID: AtomicUsize = ATOMIC_USIZE_INIT;
pub struct RootScheme {
next_id: AtomicUsize,
handles: RwLock<BTreeMap<usize, Arc<UserInner>>>
}
impl RootScheme {
pub fn new() -> RootScheme {
RootScheme {
next_id: AtomicUsize::new(0),
handles: RwLock::new(BTreeMap::new())
}
}
}
impl Scheme for RootScheme {
fn open(&self, path: &[u8], _flags: usize, uid: u32, _gid: u32) -> Result<usize> {
if uid == 0 {
let context = {
let contexts = context::contexts();
let context = contexts.current().ok_or(Error::new(ESRCH))?;
Arc::downgrade(&context)
};
let id = self.next_id.fetch_add(1, Ordering::SeqCst);
let inner = {
let mut schemes = scheme::schemes_mut();
if schemes.get_name(path).is_some() {
return Err(Error::new(EEXIST));
}
let inner = Arc::new(UserInner::new(id, context));
let scheme_id = schemes.insert(path.to_vec().into_boxed_slice(), Arc::new(Box::new(UserScheme::new(Arc::downgrade(&inner))))).expect("failed to insert user scheme");
inner.scheme_id.store(scheme_id, Ordering::SeqCst);
inner
};
self.handles.write().insert(id, inner);
Ok(id)
} else {
Err(Error::new(EACCES))
}
}
fn dup(&self, file: usize) -> Result<usize> {
let mut handles = self.handles.write();
let inner = {
let inner = handles.get(&file).ok_or(Error::new(EBADF))?;
inner.clone()
};
let id = self.next_id.fetch_add(1, Ordering::SeqCst);
handles.insert(id, inner);
Ok(id)
}
fn read(&self, file: usize, buf: &mut [u8]) -> Result<usize> {
let inner = {
let handles = self.handles.read();
let inner = handles.get(&file).ok_or(Error::new(EBADF))?;
inner.clone()
};
inner.read(buf)
}
fn write(&self, file: usize, buf: &[u8]) -> Result<usize> {
let inner = {
let handles = self.handles.read();
let inner = handles.get(&file).ok_or(Error::new(EBADF))?;
inner.clone()
};
inner.write(buf)
}
fn fevent(&self, file: usize, _flags: usize) -> Result<usize> {
Ok(file)
}
fn fsync(&self, _file: usize) -> Result<usize> {
Ok(0)
}
fn close(&self, file: usize) -> Result<usize> {
self.handles.write().remove(&file).ok_or(Error::new(EBADF)).and(Ok(0))
}
}