replace sys_read by sys_getdents64

sys_getdents64 is compatible to Linux' system call getdents64.
Consequently, it offers the reusing of an existing ABI.

src/fd/mod.rs

@@ -1,4 +1,5 @@
 use alloc::sync::Arc;
+use alloc::vec::Vec;
 use core::sync::atomic::{AtomicI32, Ordering};
 
 use ahash::RandomState;
@@ -147,7 +148,7 @@ pub(crate) trait ObjectInterface: Sync + Send + core::fmt::Debug + DynClone {
 	/// 'readdir' returns a pointer to a dirent structure
 	/// representing the next directory entry in the directory stream
 	/// pointed to by the file descriptor
-	fn readdir(&self) -> Result<Option<DirectoryEntry>, IoError> {
+	fn readdir(&self) -> Result<Vec<DirectoryEntry>, IoError> {
 		Err(IoError::EINVAL)
 	}
 

src/fs/fuse.rs

@@ -1387,7 +1387,9 @@ impl VfsNode for FuseDirectory {
 					dirent.d_namelen.try_into().unwrap(),
 				)
 			};
-			entries.push(DirectoryEntry::new(name));
+			entries.push(DirectoryEntry::new(unsafe {
+				core::str::from_utf8_unchecked(name).to_string()
+			}));
 		}
 
 		let (cmd, mut rsp) = create_release(fuse_nid, fuse_fh);

src/fs/mem.rs

@@ -426,7 +426,7 @@ impl VfsNode for MemDirectory {
 		} else {
 			let mut entries: Vec<DirectoryEntry> = Vec::new();
 			for name in self.inner.read().keys() {
-				entries.push(DirectoryEntry::new(name.as_bytes()));
+				entries.push(DirectoryEntry::new(name.to_string()));
 			}
 
 			Ok(entries)

src/fs/mod.rs

@@ -7,9 +7,7 @@ use alloc::boxed::Box;
 use alloc::string::{String, ToString};
 use alloc::sync::Arc;
 use alloc::vec::Vec;
-use core::ffi::CStr;
-use core::fmt;
-use core::sync::atomic::{AtomicUsize, Ordering};
+use core::sync::atomic::Ordering;
 
 use hermit_sync::OnceCell;
 use mem::MemDirectory;
@@ -22,36 +20,14 @@ use crate::time::{timespec, SystemTime};
 
 pub(crate) static FILESYSTEM: OnceCell<Filesystem> = OnceCell::new();
 
-pub const MAX_NAME_LENGTH: usize = 256;
-
-#[repr(C)]
-#[derive(Copy, Clone)]
+#[derive(Debug, Clone)]
 pub struct DirectoryEntry {
-	pub d_name: [u8; MAX_NAME_LENGTH],
+	pub name: String,
 }
 
 impl DirectoryEntry {
-	pub fn new(d_name: &[u8]) -> Self {
-		let len = core::cmp::min(d_name.len(), MAX_NAME_LENGTH);
-		let mut entry = Self {
-			d_name: [0; MAX_NAME_LENGTH],
-		};
-
-		entry.d_name[..len].copy_from_slice(&d_name[..len]);
-
-		entry
-	}
-}
-
-impl fmt::Debug for DirectoryEntry {
-	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-		let d_name = unsafe { CStr::from_ptr(self.d_name.as_ptr() as _) }
-			.to_str()
-			.unwrap();
-
-		f.debug_struct("DirectoryEntry")
-			.field("d_name", &d_name)
-			.finish()
+	pub fn new(name: String) -> Self {
+		Self { name }
 	}
 }
 
@@ -147,38 +123,18 @@ pub(crate) trait VfsNode: core::fmt::Debug {
 	}
 }
 
-#[derive(Debug)]
-struct DirectoryReader {
-	pos: AtomicUsize,
-	data: Vec<DirectoryEntry>,
-}
+#[derive(Debug, Clone)]
+struct DirectoryReader(Vec<DirectoryEntry>);
 
 impl DirectoryReader {
 	pub fn new(data: Vec<DirectoryEntry>) -> Self {
-		Self {
-			pos: AtomicUsize::new(0),
-			data,
-		}
+		Self(data)
 	}
 }
 
 impl ObjectInterface for DirectoryReader {
-	fn readdir(&self) -> Result<Option<DirectoryEntry>, IoError> {
-		let pos = self.pos.fetch_add(1, Ordering::SeqCst);
-		if pos < self.data.len() {
-			Ok(Some(self.data[pos]))
-		} else {
-			Ok(None)
-		}
-	}
-}
-
-impl Clone for DirectoryReader {
-	fn clone(&self) -> Self {
-		Self {
-			pos: AtomicUsize::new(self.pos.load(Ordering::SeqCst)),
-			data: self.data.clone(),
-		}
+	fn readdir(&self) -> Result<Vec<DirectoryEntry>, IoError> {
+		Ok(self.0.clone())
 	}
 }
 

src/lib.rs

@@ -252,9 +252,9 @@ pub(crate) extern "C" fn __sys_free(ptr: *mut u8, size: usize, align: usize) {
 #[cfg(target_os = "none")]
 extern "C" fn initd(_arg: usize) {
 	extern "C" {
-		#[cfg(all(not(test), not(feature = "syscall")))]
+		#[cfg(all(not(test), not(feature = "common-os")))]
 		fn runtime_entry(argc: i32, argv: *const *const u8, env: *const *const u8) -> !;
-		#[cfg(all(not(test), feature = "syscall"))]
+		#[cfg(all(not(test), feature = "common-os"))]
 		fn main(argc: i32, argv: *const *const u8, env: *const *const u8);
 		#[cfg(feature = "newlib")]
 		fn init_lwip();
@@ -297,9 +297,9 @@ extern "C" fn initd(_arg: usize) {
 	#[cfg(not(test))]
 	unsafe {
 		// And finally start the application.
-		#[cfg(all(not(test), not(feature = "syscall")))]
+		#[cfg(all(not(test), not(feature = "common-os")))]
 		runtime_entry(argc, argv, environ);
-		#[cfg(all(not(test), feature = "syscall"))]
+		#[cfg(all(not(test), feature = "common-os"))]
 		main(argc, argv, environ);
 	}
 	#[cfg(test)]

src/syscalls/mod.rs

@@ -1,6 +1,7 @@
 #![allow(clippy::result_unit_err)]
 
 use core::ffi::CStr;
+use core::marker::PhantomData;
 
 #[cfg(feature = "newlib")]
 use hermit_sync::InterruptTicketMutex;
@@ -21,7 +22,7 @@ use crate::env;
 use crate::fd::{
 	dup_object, get_object, remove_object, AccessPermission, FileDescriptor, IoCtl, OpenOption,
 };
-use crate::fs::{self, DirectoryEntry, FileAttr};
+use crate::fs::{self, FileAttr};
 use crate::syscalls::interfaces::SyscallInterface;
 #[cfg(target_os = "none")]
 use crate::{__sys_free, __sys_malloc, __sys_realloc};
@@ -335,45 +336,74 @@ pub extern "C" fn sys_lseek(fd: FileDescriptor, offset: isize, whence: i32) -> i
 	kernel_function!(__sys_lseek(fd, offset, whence))
 }
 
-extern "C" fn __sys_readdir(
-	fd: FileDescriptor,
-	dirent: *mut DirectoryEntry,
-	dirent_len: *mut usize,
-) -> i32 {
-	if dirent.is_null() || dirent_len.is_null() {
-		return -crate::errno::EINVAL;
+#[repr(C)]
+#[derive(Debug, Clone, Copy)]
+pub struct Dirent64 {
+	/// 64-bit inode number
+	pub d_ino: u64,
+	/// 64-bit offset to next structure
+	pub d_off: i64,
+	/// Size of this dirent
+	pub d_reclen: u16,
+	/// File type
+	pub d_type: u8,
+	/// Filename (null-terminated)
+	pub d_name: PhantomData<u8>,
+}
+
+extern "C" fn __sys_getdents64(fd: FileDescriptor, dirp: *mut Dirent64, count: usize) -> i64 {
+	if dirp.is_null() || count == 0 {
+		return -crate::errno::EINVAL as i64;
 	}
 
-	let dirent = unsafe { &mut *dirent };
-	let dirent_len = unsafe { &mut *dirent_len };
+	let limit = dirp as usize + count;
+	let mut dirp: *mut Dirent64 = dirp;
+	let mut offset: i64 = 0;
 	let obj = get_object(fd);
 	obj.map_or_else(
-		|_| -crate::errno::EINVAL,
+		|_| -crate::errno::EINVAL as i64,
 		|v| {
 			(*v).readdir().map_or_else(
-				|e| -num::ToPrimitive::to_i32(&e).unwrap(),
+				|e| -num::ToPrimitive::to_i64(&e).unwrap(),
 				|v| {
-					if let Some(v) = v {
-						*dirent = v;
-						*dirent_len = core::mem::size_of::<DirectoryEntry>();
-					} else {
-						*dirent_len = 0;
+					for i in v.iter() {
+						let len = i.name.len();
+						if dirp as usize + core::mem::size_of::<Dirent64>() + len + 1 >= limit {
+							return -crate::errno::EINVAL as i64;
+						}
+
+						let dir = unsafe { &mut *dirp };
+
+						dir.d_ino = 0;
+						dir.d_type = 0;
+						dir.d_reclen = (core::mem::size_of::<Dirent64>() + len + 1)
+							.try_into()
+							.unwrap();
+						offset += i64::from(dir.d_reclen);
+						dir.d_off = offset;
+
+						// copy null-terminated filename
+						let s = &mut dir.d_name as *mut _ as *mut u8;
+						unsafe {
+							core::ptr::copy_nonoverlapping(i.name.as_ptr(), s, len);
+							s.offset(len as isize).write_bytes(0, 1);
+						}
+
+						dirp = unsafe {
+							(dirp as *mut u8).add(dir.d_reclen as usize) as *mut Dirent64
+						};
 					}
 
-					0
+					offset
 				},
 			)
 		},
 	)
 }
 
 #[no_mangle]
-pub extern "C" fn sys_readdir(
-	fd: FileDescriptor,
-	dirent: *mut DirectoryEntry,
-	dirent_len: *mut usize,
-) -> i32 {
-	kernel_function!(__sys_readdir(fd, dirent, dirent_len))
+pub extern "C" fn sys_getdents64(fd: FileDescriptor, dirp: *mut Dirent64, count: usize) -> i64 {
+	kernel_function!(__sys_getdents64(fd, dirp, count))
 }
 
 extern "C" fn __sys_dup(fd: i32) -> i32 {