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ext2-rs
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redo error handling

sync
Szymon Walter 2018-03-21 20:40:39 +01:00
parent 934266ca4b
commit 117b8d4e75
7 changed files with 137 additions and 113 deletions
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85
src/error.rs
View File

@ -1,15 +1,60 @@
use core::fmt::{self, Display};
use alloc::String;
#[cfg(any(test, not(feature = "no_std")))]
use std::io;
/// The set of all possible errors
#[derive(Debug)]
pub enum Error {
BadMagic(u16),
OutOfBounds(usize),
AddressOutOfBounds(u32, u32, usize),
BadBlockGroupCount(u32, u32),
Other(String),
BadMagic {
magic: u16,
},
OutOfBounds {
index: usize,
},
AddressOutOfBounds {
sector: u32,
offset: u32,
size: usize,
},
BadBlockGroupCount {
by_blocks: u32,
by_inodes: u32,
},
#[cfg(any(test, not(feature = "no_std")))]
Io(io::Error),
Io {
inner: io::Error,
},
}
impl Display for Error {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match *self {
Error::Other(ref msg) => write!(f, "{}", msg),
Error::BadMagic {
magic,
} => write!(f, "invalid magic value: {}", magic),
Error::OutOfBounds {
index,
} => write!(f, "index ouf of bounds: {}", index),
Error::AddressOutOfBounds {
sector,
offset,
size,
} => write!(f, "address ouf of bounds: {}:{} with a block size of: {}",
sector, offset, size),
Error::BadBlockGroupCount {
by_blocks,
by_inodes,
} => write!(f, "conflicting block group count data; by blocks: {}, by inodes: {}", by_blocks, by_inodes),
#[cfg(any(test, not(feature = "no_std")))]
Error::Io {
ref inner,
} => write!(f, "io error: {}", inner),
}
}
}
impl From<Infallible> for Error {
@ -20,34 +65,8 @@ impl From<Infallible> for Error {
#[cfg(any(test, not(feature = "no_std")))]
impl From<io::Error> for Error {
fn from(err: io::Error) -> Error {
Error::Io(err)
}
}
impl PartialEq for Error {
fn eq(&self, rhs: &Error) -> bool {
match (self, rhs) {
(&Error::BadMagic(a), &Error::BadMagic(b)) => a == b,
(&Error::OutOfBounds(a), &Error::OutOfBounds(b)) => a == b,
(
&Error::BadBlockGroupCount(a1, a2),
&Error::BadBlockGroupCount(b1, b2),
) => a1 == b1 && a2 == b2,
_ => false,
}
}
fn ne(&self, rhs: &Error) -> bool {
match (self, rhs) {
(&Error::BadMagic(a), &Error::BadMagic(b)) => a != b,
(&Error::OutOfBounds(a), &Error::OutOfBounds(b)) => a != b,
(
&Error::BadBlockGroupCount(a1, a2),
&Error::BadBlockGroupCount(b1, b2),
) => a1 != b1 || a2 != b2,
_ => false,
}
fn from(inner: io::Error) -> Error {
Error::Io { inner }
}
}

64
src/fs.rs
View File

@ -30,10 +30,7 @@ pub struct Ext2<S: Size, V: Volume<u8, Address<S>>> {
block_groups: Struct<Vec<BlockGroupDescriptor>, S>,
}
impl<S: Size, V: Volume<u8, Address<S>>> Ext2<S, V>
where
Error: From<V::Error>,
{
impl<S: Size, V: Volume<u8, Address<S>>> Ext2<S, V> {
pub fn new(volume: V) -> Result<Ext2<S, V>, Error> {
let superblock = unsafe { Struct::from(Superblock::find(&volume)?) };
let block_groups_offset = Address::with_block_size(
@ -45,7 +42,10 @@ where
.inner
.block_group_count()
.map(|count| count as usize)
.map_err(|(a, b)| Error::BadBlockGroupCount(a, b))?;
.map_err(|(a, b)| Error::BadBlockGroupCount {
by_blocks: a,
by_inodes: b,
})?;
let block_groups = unsafe {
BlockGroupDescriptor::find_descriptor_table(
&volume,
@ -70,7 +70,7 @@ where
self.superblock.offset,
);
let commit = slice.commit();
self.volume.commit(commit).map_err(|err| Error::from(err))?;
self.volume.commit(commit).map_err(|err| err.into())?;
}
// block group descriptors
@ -78,7 +78,7 @@ where
for descr in &self.block_groups.inner {
let slice = VolumeSlice::from_cast(descr, offset);
let commit = slice.commit();
self.volume.commit(commit).map_err(|err| Error::from(err))?;
self.volume.commit(commit).map_err(|err| err.into())?;
offset =
offset + Address::from(mem::size_of::<BlockGroupDescriptor>());
}
@ -96,13 +96,18 @@ where
let block_size = self.block_size();
let offset = 0;
for (data, _) in InodeBlocks::new(&inode) {
let data_size = block_size
.min(total_size - read_size)
.min(buf.len() - offset);
let end = offset + data_size;
buf[offset..end].copy_from_slice(&data[..data_size]);
read_size += data_size;
for block in InodeBlocks::new(&inode) {
match block {
Ok((data, _)) => {
let data_size = block_size
.min(total_size - read_size)
.min(buf.len() - offset);
let end = offset + data_size;
buf[offset..end].copy_from_slice(&data[..data_size]);
read_size += data_size;
}
Err(err) => return Err(err.into()),
}
}
Ok(read_size)
@ -180,7 +185,10 @@ impl<S: Size, V: Volume<u8, Address<S>>> Ext2<S, V> {
self.superblock()
.block_group_count()
.map(|count| count as usize)
.map_err(|(a, b)| Error::BadBlockGroupCount(a, b))
.map_err(|(a, b)| Error::BadBlockGroupCount {
by_blocks: a,
by_inodes: b,
})
}
pub fn total_block_count(&self) -> usize {
@ -224,9 +232,8 @@ pub struct Inodes<'a, S: 'a + Size, V: 'a + Volume<u8, Address<S>>> {
index: usize,
}
impl<'a, S: Size, V: 'a + Volume<u8, Address<S>>> Iterator for Inodes<'a, S, V>
where
Error: From<V::Error>,
impl<'a, S: Size, V: 'a + Volume<u8, Address<S>>> Iterator
for Inodes<'a, S, V>
{
type Item = (Inode<'a, S, V>, Address<S>);
@ -293,7 +300,7 @@ impl<'a, S: 'a + Size, V: 'a + Volume<u8, Address<S>>> Inode<'a, S, V> {
);
let size = Address::from(4_u64);
let slice = self.fs.volume.slice(addr..addr + size);
slice.and_then(|slice| unsafe {
slice.ok().and_then(|slice| unsafe {
NonZero::new(u32::from_le(slice.dynamic_cast::<u32>().0))
})
} else if index < bs4 * bs4 + bs4 + 12 {
@ -344,9 +351,8 @@ pub struct InodeBlocks<'a: 'b, 'b, S: 'a + Size, V: 'a + Volume<u8, Address<S>>>
index: usize,
}
impl<'a, 'b, S: Size, V: 'a + Volume<u8, Address<S>>> InodeBlocks<'a, 'b, S, V>
where
Error: From<V::Error>,
impl<'a, 'b, S: Size, V: 'a + Volume<u8, Address<S>>>
InodeBlocks<'a, 'b, S, V>
{
pub fn new(inode: &'b Inode<'a, S, V>) -> InodeBlocks<'a, 'b, S, V> {
InodeBlocks { inode, index: 0 }
@ -355,10 +361,8 @@ where
impl<'a, 'b, S: Size, V: 'a + Volume<u8, Address<S>>> Iterator
for InodeBlocks<'a, 'b, S, V>
where
Error: From<V::Error>,
{
type Item = (VolumeSlice<'a, u8, Address<S>>, Address<S>);
type Item = Result<(VolumeSlice<'a, u8, Address<S>>, Address<S>), V::Error>;
fn next(&mut self) -> Option<Self::Item> {
let block = self.inode.block(self.index);
@ -377,7 +381,7 @@ where
self.inode.fs.log_block_size(),
)
})
.and_then(|block| {
.map(|block| {
let offset = block.start;
self.inode
.fs
@ -467,7 +471,7 @@ mod tests {
println!("{:?}", inode.0);
let size = inode.0.size();
for block in InodeBlocks::new(&inode.0) {
let (data, _) = block;
let (data, _) = block.unwrap();
assert_eq!(data.len(), fs.block_size());
println!("{:?}", &data[..size]);
let _ = str::from_utf8(&data[..size])
@ -490,9 +494,11 @@ mod tests {
buf.set_len(inode.size());
}
let size = fs.read_inode(&mut buf[..], &inode);
assert_eq!(size, Ok(inode.size()));
assert!(size.is_ok());
let size = size.unwrap();
assert_eq!(size, inode.size());
unsafe {
buf.set_len(size.unwrap());
buf.set_len(size);
}
}
}

3
src/lib.rs
View File

@ -5,15 +5,16 @@
#![feature(const_fn)]
#![feature(step_trait)]
#![feature(nonzero)]
#![feature(associated_type_defaults)]
#![cfg_attr(all(not(test), feature = "no_std"), no_std)]
#[macro_use]
extern crate alloc;
#[macro_use]
extern crate bitflags;
#[cfg(any(test, not(feature = "no_std")))]
extern crate core;
extern crate spin;
pub mod error;
pub mod sys;

30
src/sys/block_group.rs
View File

@ -55,18 +55,15 @@ impl BlockGroupDescriptor {
pub unsafe fn find_descriptor<S: Size, V: Volume<u8, Address<S>>>(
haystack: &V,
offset: Address<S>,
) -> Result<(BlockGroupDescriptor, Address<S>), Error>
where
Error: From<V::Error>,
{
) -> Result<(BlockGroupDescriptor, Address<S>), Error> {
let end =
offset + Address::from(mem::size_of::<BlockGroupDescriptor>());
if haystack.size() < end {
return Err(Error::AddressOutOfBounds(
end.sector(),
end.offset(),
end.sector_size(),
));
return Err(Error::AddressOutOfBounds {
sector: end.sector(),
offset: end.offset(),
size: end.sector_size(),
});
}
let descr = haystack
@ -80,18 +77,15 @@ impl BlockGroupDescriptor {
haystack: &V,
offset: Address<S>,
count: usize,
) -> Result<(Vec<BlockGroupDescriptor>, Address<S>), Error>
where
Error: From<V::Error>,
{
) -> Result<(Vec<BlockGroupDescriptor>, Address<S>), Error> {
let end = offset
+ Address::from(count * mem::size_of::<BlockGroupDescriptor>());
if haystack.size() < end {
return Err(Error::AddressOutOfBounds(
end.sector(),
end.offset(),
end.sector_size(),
));
return Err(Error::AddressOutOfBounds {
sector: end.sector(),
offset: end.offset(),
size: end.sector_size(),
});
}
let mut vec = Vec::with_capacity(count);

15
src/sys/inode.rs
View File

@ -101,21 +101,18 @@ impl Inode {
haystack: &V,
offset: Address<S>,
size: usize,
) -> Result<(Inode, Address<S>), Error>
where
Error: From<V::Error>,
{
) -> Result<(Inode, Address<S>), Error> {
if size != mem::size_of::<Inode>() {
unimplemented!("inodes with a size != 128");
}
let end = offset + Address::from(size);
if haystack.size() < end {
return Err(Error::AddressOutOfBounds(
end.sector(),
end.offset(),
end.sector_size(),
));
return Err(Error::AddressOutOfBounds {
sector: end.sector(),
offset: end.offset(),
size: end.sector_size(),
});
}
let inode = haystack

19
src/sys/superblock.rs
View File

@ -197,18 +197,15 @@ impl Debug for Superblock {
impl Superblock {
pub unsafe fn find<S: Size, V: Volume<u8, Address<S>>>(
haystack: &V,
) -> Result<(Superblock, Address<S>), Error>
where
Error: From<V::Error>,
{
) -> Result<(Superblock, Address<S>), Error> {
let offset = Address::from(1024_usize);
let end = offset + Address::from(mem::size_of::<Superblock>());
if haystack.size() < end {
return Err(Error::AddressOutOfBounds(
end.sector(),
end.offset(),
end.sector_size(),
));
return Err(Error::AddressOutOfBounds {
sector: end.sector(),
offset: end.offset(),
size: end.sector_size(),
});
}
let superblock = {
@ -218,7 +215,9 @@ impl Superblock {
};
if superblock.0.magic != EXT2_MAGIC {
Err(Error::BadMagic(superblock.0.magic))
Err(Error::BadMagic {
magic: superblock.0.magic,
})
} else {
Ok(superblock)
}

34
src/volume/mod.rs
View File

@ -6,7 +6,7 @@ use alloc::Vec;
use alloc::boxed::Box;
use alloc::borrow::{Cow, ToOwned};
use error::Infallible;
use error::Error;
use sector::{Address, Size};
pub mod length;
@ -17,7 +17,7 @@ where
[T]: ToOwned,
Idx: PartialEq + PartialOrd,
{
type Error;
type Error: Into<Error>;
fn size(&self) -> Length<Idx>;
fn commit(
@ -32,13 +32,7 @@ where
fn slice<'a>(
&'a self,
range: Range<Idx>,
) -> Option<VolumeSlice<'a, T, Idx>> {
if self.size() >= range.end && self.size() > range.start {
unsafe { Some(self.slice_unchecked(range)) }
} else {
None
}
}
) -> Result<VolumeSlice<'a, T, Idx>, Self::Error>;
}
pub struct VolumeSlice<'a, T: 'a, Idx>
@ -233,7 +227,7 @@ macro_rules! impl_slice {
T: Clone,
[T]: ToOwned,
{
type Error = Infallible;
type Error = Error;
fn size(&self) -> Length<Address<S>> {
Length::Bounded(
@ -244,7 +238,7 @@ macro_rules! impl_slice {
fn commit(
&mut self,
slice: Option<VolumeCommit<T, Address<S>>>,
) -> Result<(), Infallible> {
) -> Result<(), Self::Error> {
slice.map(|slice| {
let index = slice.at_index().into_index() as usize;
let end = index + slice.as_ref().len();
@ -269,6 +263,21 @@ macro_rules! impl_slice {
index,
)
}
fn slice<'a>(
&'a self,
range: Range<Address<S>>,
) -> Result<VolumeSlice<'a, T, Address<S>>, Self::Error> {
if self.size() >= range.end {
unsafe { Ok(self.slice_unchecked(range)) }
} else {
Err(Error::AddressOutOfBounds {
sector: range.end.sector(),
offset: range.end.offset(),
size: range.end.sector_size()
})
}
}
}
};
($volume:ty) => {
@ -344,7 +353,7 @@ mod file {
fn slice<'a>(
&'a self,
range: Range<Address<S>>,
) -> Option<VolumeSlice<'a, u8, Address<S>>> {
) -> Result<VolumeSlice<'a, u8, Address<S>>, Self::Error> {
let index = range.start;
let mut vec = Vec::with_capacity((range.end - range.start)
.into_index()
@ -357,7 +366,6 @@ mod file {
.seek(SeekFrom::Start(index.into_index()))
.and_then(|_| refmut.read_exact(&mut vec[..]))
.map(move |_| VolumeSlice::new_owned(vec, index))
.ok()
}
}
}