sel4_async_block_io/
disk.rs

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1//
2// Copyright 2023, Colias Group, LLC
3//
4// SPDX-License-Identifier: BSD-2-Clause
5//
6
7use core::mem;
8use core::ops::Range;
9
10use gpt_disk_types::{GptHeader, MasterBootRecord, MbrPartitionRecord};
11use num_enum::{IntoPrimitive, TryFromPrimitive};
12
13use crate::{access::ReadOnly, read_bytes, BlockIO, Partition};
14
15pub struct Disk<T> {
16    io: T,
17}
18
19#[derive(Debug)]
20pub enum DiskError<E> {
21    IOError(E),
22    MbrInvalidSignature,
23}
24
25impl<E> From<E> for DiskError<E> {
26    fn from(io_error: E) -> Self {
27        Self::IOError(io_error)
28    }
29}
30
31pub struct Mbr {
32    inner: MasterBootRecord,
33}
34
35impl Mbr {
36    fn new<E>(inner: MasterBootRecord) -> Result<Self, DiskError<E>> {
37        if inner.signature != [0x55, 0xaa] {
38            return Err(DiskError::MbrInvalidSignature);
39        }
40        Ok(Self { inner })
41    }
42
43    pub fn disk_signature(&self) -> [u8; 4] {
44        self.inner.unique_mbr_disk_signature
45    }
46
47    pub fn partition(&self, i: usize) -> Option<MbrPartitionEntry> {
48        self.inner
49            .partitions
50            .get(i)
51            .copied()
52            .map(MbrPartitionEntry::new)
53    }
54}
55
56pub struct MbrPartitionEntry {
57    inner: MbrPartitionRecord,
58}
59
60impl MbrPartitionEntry {
61    fn new(inner: MbrPartitionRecord) -> Self {
62        Self { inner }
63    }
64
65    pub fn partition_id(&self) -> PartitionId {
66        self.inner.os_indicator.into()
67    }
68
69    fn lba_range(&self) -> Range<u64> {
70        let start = self.inner.starting_lba.to_u32().into();
71        let size = self.inner.size_in_lba.to_u32().into();
72        start..start.checked_add(size).unwrap()
73    }
74}
75
76#[derive(Copy, Clone, Debug, Eq, PartialEq, Ord, PartialOrd, TryFromPrimitive, IntoPrimitive)]
77#[repr(u8)]
78pub enum KnownPartitionId {
79    Free = 0x00,
80    Fat32 = 0x0c,
81}
82
83#[derive(Copy, Clone, Debug, Eq, PartialEq, Ord, PartialOrd)]
84pub enum PartitionId {
85    Known(KnownPartitionId),
86    Unknown(u8),
87}
88
89impl From<u8> for PartitionId {
90    fn from(val: u8) -> Self {
91        KnownPartitionId::try_from(val)
92            .map(Self::Known)
93            .unwrap_or_else(|_| Self::Unknown(val))
94    }
95}
96
97impl<T: BlockIO<ReadOnly>> Disk<T> {
98    pub fn new(io: T) -> Self {
99        Self { io }
100    }
101
102    fn io(&self) -> &T {
103        &self.io
104    }
105
106    pub async fn read_mbr(&self) -> Result<Mbr, DiskError<T::Error>> {
107        let mut buf = [0; mem::size_of::<MasterBootRecord>()];
108        read_bytes(self.io(), 0, &mut buf[..]).await?;
109        Mbr::new(*bytemuck::from_bytes(&buf[..]))
110    }
111
112    pub async fn read_gpt_header(&self) -> Result<GptHeader, T::Error> {
113        let mut buf = [0; mem::size_of::<GptHeader>()];
114        read_bytes(self.io(), 0, &mut buf[..]).await?;
115        Ok(*bytemuck::from_bytes(&buf[..]))
116    }
117}
118
119impl<T: BlockIO<ReadOnly>> Disk<T> {
120    pub fn partition_using_mbr(self, entry: &MbrPartitionEntry) -> Partition<T> {
121        Partition::new(self.io, entry.lba_range())
122    }
123}
sel4_async_block_io/disk.rs

sel4_async_block_io/
disk.rs
