feature: add Stat struct and fstatat()

Cargo.lock

@@ -2,17 +2,6 @@
 # It is not intended for manual editing.
 version = 3
 
-[[package]]
-name = "ahash"
-version = "0.7.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fcb51a0695d8f838b1ee009b3fbf66bda078cd64590202a864a8f3e8c4315c47"
-dependencies = [
- "getrandom",
- "once_cell",
- "version_check",
-]
-
 [[package]]
 name = "autocfg"
 version = "1.0.1"
@@ -81,26 +70,6 @@ dependencies = [
  "unsafe_unwrap",
 ]
 
-[[package]]
-name = "getrandom"
-version = "0.2.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7fcd999463524c52659517fe2cea98493cfe485d10565e7b0fb07dbba7ad2753"
-dependencies = [
- "cfg-if",
- "libc",
- "wasi",
-]
-
-[[package]]
-name = "hashbrown"
-version = "0.11.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ab5ef0d4909ef3724cc8cce6ccc8572c5c817592e9285f5464f8e86f8bd3726e"
-dependencies = [
- "ahash",
-]
-
 [[package]]
 name = "init"
 version = "0.1.0"
@@ -124,12 +93,6 @@ dependencies = [
  "vfs",
 ]
 
-[[package]]
-name = "libc"
-version = "0.2.104"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7b2f96d100e1cf1929e7719b7edb3b90ab5298072638fccd77be9ce942ecdfce"
-
 [[package]]
 name = "libcommon"
 version = "0.1.0"
@@ -182,12 +145,6 @@ dependencies = [
  "autocfg",
 ]
 
-[[package]]
-name = "once_cell"
-version = "1.8.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "692fcb63b64b1758029e0a96ee63e049ce8c5948587f2f7208df04625e5f6b56"
-
 [[package]]
 name = "osdev5"
 version = "0.1.0"
@@ -273,23 +230,11 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1230ec65f13e0f9b28d789da20d2d419511893ea9dac2c1f4ef67b8b14e5da80"
 
-[[package]]
-name = "version_check"
-version = "0.9.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5fecdca9a5291cc2b8dcf7dc02453fee791a280f3743cb0905f8822ae463b3fe"
-
 [[package]]
 name = "vfs"
 version = "0.1.0"
 dependencies = [
  "error",
- "hashbrown",
  "libcommon",
+ "syscall",
 ]
-
-[[package]]
-name = "wasi"
-version = "0.10.2+wasi-snapshot-preview1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fd6fbd9a79829dd1ad0cc20627bf1ed606756a7f77edff7b66b7064f9cb327c6"

fs/memfs/src/dir.rs

@@ -1,4 +1,4 @@
-use vfs::{VnodeImpl, VnodeKind, VnodeRef, Vnode};
+use vfs::{VnodeImpl, VnodeKind, VnodeRef, Vnode, Stat};
 use alloc::boxed::Box;
 use error::Errno;
 
@@ -50,5 +50,9 @@ impl VnodeImpl for DirInode {
     fn size(&mut self, _node: VnodeRef) -> Result<usize, Errno> {
         todo!()
     }
+
+    fn stat(&mut self, _node: VnodeRef, _stat: &mut Stat) -> Result<(), Errno> {
+        todo!();
+    }
 }
 

fs/memfs/src/file.rs

@@ -1,4 +1,4 @@
-use vfs::{VnodeImpl, VnodeKind, VnodeRef};
+use vfs::{VnodeImpl, VnodeKind, VnodeRef, Stat};
 use error::Errno;
 use crate::{BlockAllocator, Bvec};
 
@@ -53,4 +53,11 @@ impl<'a, A: BlockAllocator + Copy + 'static> VnodeImpl for FileInode<'a, A> {
     fn size(&mut self, _node: VnodeRef) -> Result<usize, Errno> {
         Ok(self.data.size())
     }
+
+    fn stat(&mut self, node: VnodeRef, stat: &mut Stat) -> Result<(), Errno> {
+        stat.size = self.data.size() as u64;
+        stat.blksize = 4096;
+        stat.mode = 0o755;
+        Ok(())
+    }
 }

fs/vfs/Cargo.toml

@@ -8,4 +8,4 @@ edition = "2021"
 [dependencies]
 error = { path = "../../error" }
 libcommon = { path = "../../libcommon" }
-hashbrown = "0.11.*"
+syscall = { path = "../../syscall" }

fs/vfs/src/char.rs

@@ -1,4 +1,4 @@
-use crate::{VnodeImpl, VnodeKind, VnodeRef};
+use crate::{VnodeImpl, VnodeKind, VnodeRef, Stat};
 use error::Errno;
 
 /// Generic character device trait
@@ -59,6 +59,10 @@ impl VnodeImpl for CharDeviceWrapper {
     fn size(&mut self, _node: VnodeRef) -> Result<usize, Errno> {
         panic!();
     }
+
+    fn stat(&mut self, _node: VnodeRef, _stat: &mut Stat) -> Result<(), Errno> {
+        todo!();
+    }
 }
 
 impl CharDeviceWrapper {

fs/vfs/src/lib.rs

@@ -9,6 +9,8 @@ extern crate std;
 
 extern crate alloc;
 
+pub use syscall::stat::Stat;
+
 mod block;
 pub use block::BlockDevice;
 mod fs;

fs/vfs/src/node.rs

@@ -1,4 +1,4 @@
-use crate::{File, FileMode, Filesystem};
+use crate::{File, FileMode, Filesystem, Stat};
 use alloc::{borrow::ToOwned, boxed::Box, rc::Rc, string::String, vec::Vec};
 use core::cell::{RefCell, RefMut};
 use core::fmt;
@@ -70,6 +70,9 @@ pub trait VnodeImpl {
     /// Resizes the file storage if necessary.
     fn write(&mut self, node: VnodeRef, pos: usize, data: &[u8]) -> Result<usize, Errno>;
 
+    /// Retrieves file status
+    fn stat(&mut self, node: VnodeRef, stat: &mut Stat) -> Result<(), Errno>;
+
     /// Reports the size of this filesystem object in bytes
     fn size(&mut self, node: VnodeRef) -> Result<usize, Errno>;
 }
@@ -339,6 +342,15 @@ impl Vnode {
             Err(Errno::NotImplemented)
         }
     }
+
+    /// Reports file status
+    pub fn stat(self: &VnodeRef, stat: &mut Stat) -> Result<(), Errno> {
+        if let Some(ref mut data) = *self.data() {
+            data.stat(self.clone(), stat)
+        } else {
+            Err(Errno::NotImplemented)
+        }
+    }
 }
 
 impl fmt::Debug for Vnode {

init/src/main.rs

@@ -5,13 +5,18 @@
 #[macro_use]
 extern crate libusr;
 
+use libusr::io;
+
 #[no_mangle]
 fn main() -> i32 {
     let mut buf = [0; 128];
+    let stat = io::stat("/test.txt").unwrap();
 
     print!("\x1B[2J\x1B[1;1H");
     println!("Hello!");
 
+    println!("test.txt: {:?}", stat);
+
     loop {
         print!("> ");
 

kernel/src/syscall.rs

@@ -5,7 +5,10 @@ use core::mem::size_of;
 use core::time::Duration;
 use error::Errno;
 use libcommon::{Read, Write};
-use syscall::abi;
+use syscall::{
+    abi,
+    stat::{Stat, AT_FDCWD},
+};
 
 fn translate(virt: usize) -> Option<usize> {
     let mut res: usize;
@@ -19,6 +22,13 @@ fn translate(virt: usize) -> Option<usize> {
     }
 }
 
+fn validate_user_ptr_struct<'a, T>(base: usize) -> Result<&'a mut T, Errno> {
+    let bytes = validate_user_ptr(base, size_of::<T>())?;
+    Ok(unsafe {
+        &mut *(bytes.as_mut_ptr() as *mut T)
+    })
+}
+
 fn validate_user_ptr<'a>(base: usize, len: usize) -> Result<&'a mut [u8], Errno> {
     if base > mem::KERNEL_OFFSET || base + len > mem::KERNEL_OFFSET {
         warnln!(
@@ -133,6 +143,23 @@ pub unsafe fn syscall(num: usize, args: &[usize]) -> Result<usize, Errno> {
 
             io.file(args[0])?.write(buf)
         }
+        abi::SYS_FSTATAT => {
+            let proc = Process::current();
+            let mut io = proc.io.lock();
+            let fd = args[0];
+            let filename = validate_user_str(args[1], 256)?;
+            let buf = validate_user_ptr_struct::<Stat>(args[2])?;
+
+            // TODO "self" flag
+            let at = if fd as i32 != AT_FDCWD {
+                todo!();
+            } else {
+                None
+            };
+            let node = io.ioctx().find(at, filename, true)?;
+            node.stat(buf)?;
+            Ok(0)
+        }
 
         // Extra system calls
         abi::SYS_EX_DEBUG_TRACE => {

libusr/src/io.rs

@@ -1,8 +1,29 @@
-use crate::sys;
+use crate::sys::{self, Stat};
+use syscall::stat::AT_FDCWD;
+use core::mem::MaybeUninit;
 use core::fmt;
 
 const STDOUT_FILENO: i32 = 0;
 
+pub fn stat(pathname: &str) -> Result<Stat, ()> {
+    let mut buf = MaybeUninit::<Stat>::uninit();
+    let mut path = [0u8; 256];
+
+    let bytes = pathname.as_bytes();
+    path[..pathname.len()].copy_from_slice(&bytes);
+    path[pathname.len()] = 0;
+
+    unsafe {
+        let res = sys::sys_fstatat(AT_FDCWD, path.as_ptr(), buf.as_mut_ptr(), 0);
+        if res != 0 {
+            todo!();
+        }
+        Ok(buf.assume_init())
+    }
+}
+
+// print!/println! group
+
 #[macro_export]
 macro_rules! print {
     ($($args:tt)+) => ($crate::io::_print(format_args!($($args)+)))

libusr/src/lib.rs

@@ -8,7 +8,8 @@ pub mod os;
 pub mod io;
 
 pub mod sys {
-    pub use syscall::*;
+    pub use syscall::calls::*;
+    pub use syscall::stat::Stat;
 }
 
 #[link_section = ".text._start"]

syscall/src/abi.rs

@@ -7,3 +7,4 @@ pub const SYS_EXIT: usize = 1;
 pub const SYS_READ: usize = 2;
 pub const SYS_WRITE: usize = 3;
 pub const SYS_OPEN: usize = 4;
+pub const SYS_FSTATAT: usize = 5;

syscall/src/calls.rs

@@ -1,4 +1,5 @@
 use crate::abi;
+use crate::stat::Stat;
 
 macro_rules! syscall {
     ($num:expr, $a0:expr) => {{
@@ -22,6 +23,13 @@ macro_rules! syscall {
              in("x8") $num, options(nostack));
         res
     }};
+    ($num:expr, $a0:expr, $a1:expr, $a2:expr, $a3:expr) => {{
+        let mut res: usize = $a0;
+        asm!("svc #0",
+             inout("x0") res, in("x1") $a1, in("x2") $a2,
+             in("x3") $a3, in("x8") $num, options(nostack));
+        res
+    }};
 }
 
 #[inline(always)]
@@ -42,7 +50,12 @@ pub unsafe fn sys_ex_debug_trace(msg: *const u8, len: usize) -> usize {
 
 #[inline(always)]
 pub unsafe fn sys_open(pathname: *const u8, mode: u32, flags: u32) -> i32 {
-    syscall!(abi::SYS_OPEN, pathname as usize, mode as usize, flags as usize) as i32
+    syscall!(
+        abi::SYS_OPEN,
+        pathname as usize,
+        mode as usize,
+        flags as usize
+    ) as i32
 }
 
 #[inline(always)]
@@ -54,3 +67,14 @@ pub unsafe fn sys_read(fd: i32, data: *mut u8, len: usize) -> isize {
 pub unsafe fn sys_write(fd: i32, data: *const u8, len: usize) -> isize {
     syscall!(abi::SYS_WRITE, fd as usize, data as usize, len) as isize
 }
+
+#[inline(always)]
+pub unsafe fn sys_fstatat(at: i32, pathname: *const u8, statbuf: *mut Stat, flags: i32) -> i32 {
+    syscall!(
+        abi::SYS_FSTATAT,
+        at as usize,
+        pathname as usize,
+        statbuf as usize,
+        flags as usize
+    ) as i32
+}

syscall/src/lib.rs

@@ -5,9 +5,10 @@
 compile_error!("Not yet implemented");
 
 pub mod abi;
-pub use abi::*;
+
+pub mod stat;
 
 #[cfg(feature = "user")]
-mod calls;
+pub mod calls;
 #[cfg(feature = "user")]
 pub use calls::*;

syscall/src/stat.rs

@@ -0,0 +1,9 @@
+pub const AT_FDCWD: i32 = -2;
+
+#[derive(Clone, Copy, Debug)]
+#[repr(C)]
+pub struct Stat {
+    pub mode: u32,
+    pub size: u64,
+    pub blksize: u32,
+}