jD91mZM2
102 lines
2.8 KiB
Rust
102 lines
2.8 KiB
Rust
use alloc::{BTreeMap, Vec};
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use core::sync::atomic::{AtomicUsize, Ordering};
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use memory::{free_frames, used_frames};
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use spin::Mutex;
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use syscall::data::StatVfs;
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use syscall::error::*;
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use syscall::scheme::Scheme;
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use syscall;
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struct Address {
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phys: usize,
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len: usize,
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virt: usize
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}
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pub struct MemoryScheme {
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handles: Mutex<BTreeMap<usize, Vec<Address>>>,
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next_id: AtomicUsize
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}
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impl MemoryScheme {
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pub fn new() -> Self {
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Self {
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handles: Mutex::new(BTreeMap::new()),
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next_id: AtomicUsize::new(0)
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}
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}
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}
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impl Scheme for MemoryScheme {
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fn open(&self, _path: &[u8], _flags: usize, _uid: u32, _gid: u32) -> Result<usize> {
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let id = self.next_id.fetch_add(1, Ordering::SeqCst);
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self.handles.lock().insert(id, Vec::new());
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Ok(0)
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}
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fn fstatvfs(&self, _file: usize, stat: &mut StatVfs) -> Result<usize> {
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let used = used_frames() as u64;
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let free = free_frames() as u64;
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stat.f_bsize = 4096;
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stat.f_blocks = used + free;
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stat.f_bfree = free;
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stat.f_bavail = stat.f_bfree;
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Ok(0)
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}
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fn fmap(&self, id: usize, _offset: usize, len: usize) -> Result<usize> {
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let mut handles = self.handles.lock();
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let handle = handles.get_mut(&id).ok_or(Error::new(ENOENT))?;
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// Warning: These functions are bypassing the root check.
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let phys = syscall::inner_physalloc(len)?;
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let virt = syscall::inner_physmap(phys, len, syscall::flag::MAP_WRITE).map_err(|err| {
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syscall::inner_physfree(phys, len).expect("newly allocated region failed to free");
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err
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})?;
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handle.push(Address {
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phys,
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len,
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virt
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});
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Ok(virt)
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}
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fn fcntl(&self, _id: usize, _cmd: usize, _arg: usize) -> Result<usize> {
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Ok(0)
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}
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fn fpath(&self, _id: usize, buf: &mut [u8]) -> Result<usize> {
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let mut i = 0;
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let scheme_path = b"memory:";
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while i < buf.len() && i < scheme_path.len() {
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buf[i] = scheme_path[i];
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i += 1;
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}
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Ok(i)
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}
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fn close(&self, id: usize) -> Result<usize> {
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let allocations = self.handles.lock()
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.remove(&id)
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.ok_or(Error::new(ENOENT))?;
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for addr in allocations {
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// physunmap fails if already unmapped
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// physfree can't currently fail
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//
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// What if somebody with root already freed the physical address?
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// (But left the mapping, which means we attempt to free it again)
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// I'd rather not think about it.
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// (Still, that requires root)
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let _ = syscall::inner_physunmap(addr.virt)
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.and_then(|_| syscall::inner_physfree(addr.phys, addr.len));
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}
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Ok(0)
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}
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}
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