yggdrasil/src/fs/mod.rs

58 lines
1.6 KiB
Rust

//! Filesystem implementations
use core::ptr::NonNull;
use kernel_util::util::OneTimeInit;
use memfs::block::{self, BlockAllocator};
use vfs::VnodeRef;
use yggdrasil_abi::{error::Error, io::MountOptions};
use crate::mem::{
self,
phys::{self, PageUsage},
ConvertAddress,
};
pub mod devfs;
/// Describes in-memory filesystem image used as initial root
pub struct Initrd {
/// Page-aligned start address of the initrd
pub phys_page_start: usize,
/// Page-aligned length
pub phys_page_len: usize,
/// Safe reference to the initrd data slice
pub data: &'static [u8],
}
/// Holds reference to the data of initrd as well as its page-aligned physical memory region
pub static INITRD_DATA: OneTimeInit<Initrd> = OneTimeInit::new();
/// Implementation of [memfs::block::BlockAllocator] for the kernel
pub struct FileBlockAllocator;
unsafe impl BlockAllocator for FileBlockAllocator {
fn alloc() -> Result<NonNull<u8>, Error> {
// TODO make this a static assertion
assert_eq!(block::SIZE, 4096);
let page = phys::alloc_page(PageUsage::Used)?;
Ok(unsafe { NonNull::new_unchecked(page.virtualize() as *mut _) })
}
unsafe fn dealloc(block: NonNull<u8>) {
let page = block.as_ptr() as usize;
assert!(page > mem::KERNEL_VIRT_OFFSET);
phys::free_page(page.physicalize());
}
}
/// Constructs an instance of a filesystem for given set of [MountOptions]
pub fn create_filesystem(options: &MountOptions) -> Result<VnodeRef, Error> {
let fs_name = options.filesystem.unwrap();
match fs_name {
"devfs" => Ok(devfs::root().clone()),
_ => todo!(),
}
}