Better virtual file system, keyboard through MMIO&VirtIO

crates/shared/Cargo.toml

@@ -5,6 +5,7 @@ edition = "2024"
 
 [dependencies]
 bffs = { path = "../bffs" }
+io = { path = "../io" }
 
 [features]
 kernel = []

crates/shared/src/fs.rs

@@ -1,9 +1,16 @@
+#[derive(Debug)]
 pub struct File {
     fd: u64,
 }
 
 impl File {
+    /// # Safety
+    /// The file descriptor must be valid
     pub unsafe fn new(fd: u64) -> Self {
         Self { fd }
     }
+
+    pub fn as_fd(&self) -> u64 {
+        self.fd
+    }
 }

crates/shared/src/syscall.rs

@@ -1,10 +1,15 @@
 use core::{alloc::Layout, time::Duration};
 
 use bffs::path::Path;
+use io::SeekFrom;
+
+use crate::fs::File;
 
 #[repr(u64)]
 pub enum SysCall {
+    Write = 1,
     Open = 2,
+    Seek = 8,
     Alloc = 40,
     Dealloc = 41,
     Exit = 60,
@@ -17,7 +22,9 @@ pub enum SysCall {
 impl From<u64> for SysCall {
     fn from(value: u64) -> Self {
         match value {
+            1 => SysCall::Write,
             2 => SysCall::Open,
+            8 => SysCall::Seek,
             40 => SysCall::Alloc,
             41 => SysCall::Dealloc,
             60 => SysCall::Exit,
@@ -128,12 +135,29 @@ pub fn dealloc(ptr: *mut u8, layout: core::alloc::Layout) {
         syscall!(SysCall::Dealloc, ptr as u64, size as u64, align as u64);
     }
 }
-pub fn open<P: AsRef<Path>>(path: P) -> u64 {
+pub fn open<P: AsRef<Path>>(path: P) -> File {
     unsafe {
         let path_str = path.as_ref().as_str();
         let ptr = path_str.as_ptr();
         let size = path_str.len();
         let (fd, ..) = syscall!(SysCall::Open, ptr as u64, size as u64);
-        fd
+        File::new(fd)
+    }
+}
+pub fn write(file: &mut File, buf: &[u8]) {
+    unsafe {
+        let ptr = buf.as_ptr();
+        let size = buf.len();
+        syscall!(SysCall::Write, file.as_fd(), ptr as u64, size as u64);
+    }
+}
+pub fn seek(file: &mut File, seek: SeekFrom) {
+    unsafe {
+        let (discriminant, value) = match seek {
+            SeekFrom::Start(v) => (0, v),
+            SeekFrom::End(v) => (1, v as u64),
+            SeekFrom::Current(v) => (2, v as u64),
+        };
+        syscall!(SysCall::Seek, file.as_fd(), discriminant, value);
     }
 }