88 lines
2.7 KiB
Rust
88 lines
2.7 KiB
Rust
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use std::{io, error, fmt, result, cmp};
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use std::fs::File;
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use std::os::linux::fs::MetadataExt;
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use std::io::{SeekFrom, Seek};
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use crate::system;
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mod realmfs;
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mod raw;
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mod memory;
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pub use raw::RawDiskImage;
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pub use realmfs::RealmFSImage;
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use std::path::PathBuf;
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const SECTOR_SIZE: usize = 512;
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#[derive(Debug,PartialEq)]
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pub enum OpenType {
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ReadOnly,
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ReadWrite,
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MemoryOverlay,
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}
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pub trait DiskImage: Sync+Send {
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fn read_only(&self) -> bool;
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fn sector_count(&self) -> u64;
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fn disk_file(&self) -> &File;
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fn seek_to_sector(&self, sector: u64) -> Result<()> {
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if sector > self.sector_count() {
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return Err(Error::BadSectorOffset(sector));
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}
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let offset = SeekFrom::Start(sector * SECTOR_SIZE as u64);
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self.disk_file().seek(offset)
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.map_err(Error::DiskSeek)?;
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Ok(())
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}
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fn write_sectors(&mut self, start_sector: u64, buffer: &[u8]) -> Result<()>;
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fn read_sectors(&mut self, start_sector: u64, buffer: &mut [u8]) -> Result<()>;
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fn flush(&mut self) -> Result<()> { Ok(()) }
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fn disk_image_id(&self) -> &[u8];
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}
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fn generate_disk_image_id(disk_file: &File) -> Vec<u8> {
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const VIRTIO_BLK_ID_BYTES: usize = 20;
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let meta = match disk_file.metadata() {
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Ok(meta) => meta,
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Err(_) => return vec![0u8; VIRTIO_BLK_ID_BYTES]
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};
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let dev_id = format!("{}{}{}", meta.st_dev(), meta.st_rdev(), meta.st_ino());
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let bytes = dev_id.as_bytes();
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let len = cmp::min(bytes.len(), VIRTIO_BLK_ID_BYTES);
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Vec::from(&bytes[..len])
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}
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pub type Result<T> = result::Result<T, Error>;
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#[derive(Debug)]
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pub enum Error {
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ReadOnly,
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DiskOpen(PathBuf,io::Error),
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DiskOpenTooShort(PathBuf),
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DiskRead(io::Error),
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DiskWrite(io::Error),
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DiskSeek(io::Error),
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BadSectorOffset(u64),
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MemoryOverlayCreate(system::Error),
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}
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impl error::Error for Error {}
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impl fmt::Display for Error {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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use Error::*;
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match self {
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ReadOnly => write!(f, "attempted write to read-only device"),
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DiskOpen(path, err) => write!(f, "failed to open disk image {}: {}", path.display(), err),
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DiskOpenTooShort(path) => write!(f, "failed to open disk image {} because file is too short", path.display()),
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DiskRead(err) => write!(f, "error reading from disk image: {}", err),
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DiskWrite(err) => write!(f, "error writing to disk image: {}", err),
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DiskSeek(err) => write!(f, "error seeking to offset on disk image: {}", err),
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BadSectorOffset(sector) => write!(f, "attempt to access invalid sector offset {}", sector),
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MemoryOverlayCreate(err) => write!(f, "failed to create memory overlay: {}", err),
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}
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}
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}
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