refactor: move raw syscall to sys.rs, safe fs_read API, c-string fix, named struct fields

Cargo.toml

@@ -21,3 +21,6 @@ path = "examples/dark.rs"
 [profile.release]
 opt-level = "z"
 lto = "thin"
+
+[[example]]
+name = "fs_demo"

examples/fs_demo.rs

@@ -1,25 +1,12 @@
-#![no_std]
+#![no_std]
 #![no_main]
 
-use kos::fs::{FileInfo, fs_read};
-
-static FILENAME: &[u8] = b"/rd/1/readme.txt\0";
-static mut BUFFER: [u8; 256] = [0u8; 256];
+use kos::fs::fs_read;
 
 #[no_mangle]
 pub extern "C" fn _start() -> ! {
-    unsafe {
-        let info = FileInfo {
-            func:   0,
-            param1: 0,
-            param2: 0,
-            param3: 256,
-            buf:    BUFFER.as_mut_ptr(),
-            name:   FILENAME.as_ptr(),
-        };
-
-        let (_result, _bytes_read) = fs_read(&info as *const FileInfo);
-    }
-
+    let path = c"/rd/1/readme.txt";
+    let mut buf = [0u8; 512];
+    let (_status, _bytes) = fs_read(path, &mut buf);
     loop {}
 }

src/fs.rs

@@ -1,31 +1,14 @@
-use core::arch::asm;
+use core::ffi::CStr;
+use crate::sys::{syscall_fs, FileSystemRequest};
 
-/// KolibriOS Function 70 — filesystem operations
-/// Passes a pointer to a FileInfo structure via ebx
-/// int 0x40 with eax=70 is the KolibriOS FS syscall
-
-#[repr(C, packed)]
-pub struct FileInfo {
-    pub func:       u32,   // 0 = read, 1 = read folder, 2 = create/write
-    pub param1:     u32,   // offset (low)
-    pub param2:     u32,   // offset (high) or flags
-    pub param3:     u32,   // bytes to read/write
-    pub buf:        *mut u8, // pointer to buffer
-    pub name:       *const u8, // pointer to filename (ASCIIZ)
-}
-
-/// Opens/reads a file on KolibriOS using syscall eax=70
-/// Returns (eax_result, ebx_bytes_read)
-pub unsafe fn fs_read(info: *const FileInfo) -> (u32, u32) {
-    let eax_out: u32;
-    let ebx_out: u32;
-    unsafe {
-        asm!(
-            "int 0x40",
-            inlateout("eax") 70u32 => eax_out,
-            inlateout("ebx") info as u32 => ebx_out,
-            options(nostack)
-        );
-    }
-    (eax_out, ebx_out)
+pub fn fs_read(path: &CStr, buf: &mut [u8]) -> (u32, u32) {
+    let req = FileSystemRequest {
+        operation:   0,
+        offset_low:  0,
+        offset_high: 0,
+        byte_count:  buf.len() as u32,
+        buffer:      buf.as_mut_ptr() as u32,
+        path:        path.as_ptr() as u32,
+    };
+    unsafe { syscall_fs(&req) }
 }

src/lib.rs

@@ -6,6 +6,7 @@ mod nanolibc;
 pub mod allocation;
 pub mod dll;
 pub mod sys;
+pub mod fs;
 
 pub use modules::*;
 

src/sys.rs

@@ -68,3 +68,26 @@ extern "C" {
     #[link_name = "_load_dll"]
     pub fn load_dll(name: *const u8) -> *const u32;
 }
+
+#[repr(C)]
+pub struct FileSystemRequest {
+    pub operation:    u32,
+    pub offset_low:   u32,
+    pub offset_high:  u32,
+    pub byte_count:   u32,
+    pub buffer:       u32,
+    pub path:         u32,
+}
+
+pub unsafe fn syscall_fs(req: *const FileSystemRequest) -> (u32, u32) {
+    let eax_result: u32;
+    let ebx_result: u32;
+    core::arch::asm!(
+        "int 0x40",
+        inout("eax") 70u32 => eax_result,
+        in("ebx") req,
+        out("ebx") ebx_result,
+        options(nostack)
+    );
+    (eax_result, ebx_result)
+}