Rewrite getdents syscall

src/libos/src/fs/file.rs

@@ -55,8 +55,8 @@ pub trait File: Debug + Sync + Send + Any {
         return_op_unsupported_error!("set_len")
     }
 
-    fn read_entry(&self) -> Result<String> {
+    fn iterate_entries(&self, writer: &mut dyn DirentWriter) -> Result<usize> {
-        return_op_unsupported_error!("read_entry", ENOTDIR)
+        return_op_unsupported_error!("iterate_entries")
     }
 
     fn sync_all(&self) -> Result<()> {

src/libos/src/fs/file_ops/dirent.rs

@@ -1,180 +0,0 @@
-use super::*;
-
-pub fn do_getdents64(fd: FileDesc, buf: &mut [u8]) -> Result<usize> {
-    getdents_common::<u8>(fd, buf)
-}
-
-pub fn do_getdents(fd: FileDesc, buf: &mut [u8]) -> Result<usize> {
-    getdents_common::<()>(fd, buf)
-}
-
-fn getdents_common<T: DirentType + Copy>(fd: FileDesc, buf: &mut [u8]) -> Result<usize> {
-    debug!(
-        "getdents: fd: {}, buf: {:?}, buf_size: {}",
-        fd,
-        buf.as_ptr(),
-        buf.len(),
-    );
-
-    let file_ref = current!().file(fd)?;
-    let info = file_ref.metadata()?;
-    if info.type_ != FileType::Dir {
-        return_errno!(ENOTDIR, "");
-    }
-    let mut writer = unsafe { DirentBufWriter::new(buf) };
-    loop {
-        let name = match file_ref.read_entry() {
-            Err(e) => {
-                let errno = e.errno();
-                if errno == ENOENT {
-                    break;
-                }
-                return Err(e.cause_err(|_| errno!(errno, "failed to read entry")));
-            }
-            Ok(name) => name,
-        };
-        // TODO: get ino and type from dirent
-        let dirent = LinuxDirent::<T>::new(1, &name, DT_UNKNOWN);
-        if let Err(e) = writer.try_write(&dirent, &name) {
-            file_ref.seek(SeekFrom::Current(-1))?;
-            if writer.written_size == 0 {
-                return Err(e);
-            } else {
-                break;
-            }
-        }
-    }
-    Ok(writer.written_size)
-}
-
-const DT_UNKNOWN: u8 = 0;
-
-#[repr(packed)] // Don't use 'C'. Or its size will align up to 8 bytes.
-struct LinuxDirent<T: DirentType + Copy> {
-    /// Inode number
-    ino: u64,
-    /// Offset to next structure
-    offset: u64,
-    /// Size of this dirent
-    reclen: u16,
-    /// File type
-    type_: T,
-    /// Filename (null-terminated)
-    name: [u8; 0],
-}
-
-impl<T: DirentType + Copy> LinuxDirent<T> {
-    fn new(ino: u64, name: &str, d_type: u8) -> Self {
-        let ori_len = if !T::at_the_end_of_linux_dirent() {
-            core::mem::size_of::<LinuxDirent<T>>() + name.len() + 1
-        } else {
-            // pad the file type at the end
-            core::mem::size_of::<LinuxDirent<T>>() + name.len() + 1 + core::mem::size_of::<u8>()
-        };
-        let len = align_up(ori_len, 8); // align up to 8 bytes
-        Self {
-            ino,
-            offset: 0,
-            reclen: len as u16,
-            type_: T::set_type(d_type),
-            name: [],
-        }
-    }
-
-    fn len(&self) -> usize {
-        self.reclen as usize
-    }
-}
-
-impl<T: DirentType + Copy> Copy for LinuxDirent<T> {}
-
-impl<T: DirentType + Copy> Clone for LinuxDirent<T> {
-    fn clone(&self) -> Self {
-        Self {
-            ino: self.ino,
-            offset: self.offset,
-            reclen: self.reclen,
-            type_: self.type_,
-            name: self.name,
-        }
-    }
-}
-
-trait DirentType {
-    fn set_type(d_type: u8) -> Self;
-    fn at_the_end_of_linux_dirent() -> bool;
-}
-
-impl DirentType for u8 {
-    fn set_type(d_type: u8) -> Self {
-        d_type
-    }
-    fn at_the_end_of_linux_dirent() -> bool {
-        false
-    }
-}
-impl DirentType for () {
-    fn set_type(d_type: u8) -> Self {
-        Default::default()
-    }
-    fn at_the_end_of_linux_dirent() -> bool {
-        true
-    }
-}
-
-struct DirentBufWriter<'a> {
-    buf: &'a mut [u8],
-    rest_size: usize,
-    written_size: usize,
-}
-
-impl<'a> DirentBufWriter<'a> {
-    unsafe fn new(buf: &'a mut [u8]) -> Self {
-        let rest_size = buf.len();
-        DirentBufWriter {
-            buf,
-            rest_size,
-            written_size: 0,
-        }
-    }
-
-    fn try_write<T: DirentType + Copy>(
-        &mut self,
-        dirent: &LinuxDirent<T>,
-        name: &str,
-    ) -> Result<()> {
-        if self.rest_size < dirent.len() {
-            return_errno!(EINVAL, "the given buffer is too small");
-        }
-        unsafe {
-            let ptr = self.buf.as_mut_ptr().add(self.written_size) as *mut LinuxDirent<T>;
-            ptr.write(*dirent);
-            let name_ptr = ptr.add(1) as _;
-            write_cstr(name_ptr, name);
-            if T::at_the_end_of_linux_dirent() {
-                // pad zero bytes and file type at the end
-                let mut ptr = name_ptr.add(name.len() + 1);
-                let mut rest_len = {
-                    let written_len = core::mem::size_of::<LinuxDirent<T>>() + name.len() + 1;
-                    dirent.len() - written_len
-                };
-                while rest_len > 1 {
-                    ptr.write(0);
-                    ptr = ptr.add(1);
-                    rest_len -= 1;
-                }
-                // the last one is file type
-                ptr.write(DT_UNKNOWN);
-            }
-        }
-        self.rest_size -= dirent.len();
-        self.written_size += dirent.len();
-        Ok(())
-    }
-}
-
-/// Write a Rust string to C string
-unsafe fn write_cstr(ptr: *mut u8, s: &str) {
-    ptr.copy_from(s.as_ptr(), s.len());
-    ptr.add(s.len()).write(0);
-}

src/libos/src/fs/file_ops/getdents.rs

@@ -0,0 +1,216 @@
+use super::*;
+use core::marker::PhantomData;
+
+pub fn do_getdents64(fd: FileDesc, buf: &mut [u8]) -> Result<usize> {
+    getdents_common::<LinuxDirent64>(fd, buf)
+}
+
+pub fn do_getdents(fd: FileDesc, buf: &mut [u8]) -> Result<usize> {
+    getdents_common::<LinuxDirent>(fd, buf)
+}
+
+fn getdents_common<T: Dirent>(fd: FileDesc, buf: &mut [u8]) -> Result<usize> {
+    debug!(
+        "getdents: fd: {}, buf: {:?}, buf_size: {}",
+        fd,
+        buf.as_ptr(),
+        buf.len(),
+    );
+
+    let file_ref = current!().file(fd)?;
+    let info = file_ref.metadata()?;
+    if info.type_ != FileType::Dir {
+        return_errno!(ENOTDIR, "");
+    }
+    let mut writer = DirentBufWriter::<T>::new(buf);
+    let written_size = file_ref.iterate_entries(&mut writer)?;
+    Ok(written_size)
+}
+
+struct DirentBufWriter<'a, T: Dirent> {
+    buf: &'a mut [u8],
+    written_size: usize,
+    phantom: PhantomData<T>,
+}
+
+impl<'a, T: Dirent> DirentBufWriter<'a, T> {
+    fn new(buf: &'a mut [u8]) -> Self {
+        Self {
+            buf,
+            written_size: 0,
+            phantom: PhantomData,
+        }
+    }
+
+    fn try_write(&mut self, name: &str, ino: u64, type_: FileType) -> Result<usize> {
+        let dirent: T = Dirent::new(name, ino, type_);
+        if self.buf.len() - self.written_size < dirent.rec_len() {
+            return_errno!(EINVAL, "the given buffer is too small");
+        }
+        dirent.dump(&mut self.buf[self.written_size..], name, type_)?;
+        self.written_size += dirent.rec_len();
+        Ok(dirent.rec_len())
+    }
+}
+
+impl<'a, T: Dirent> DirentWriter for DirentBufWriter<'a, T> {
+    fn write_entry(
+        &mut self,
+        name: &str,
+        ino: u64,
+        type_: FileType,
+    ) -> rcore_fs::vfs::Result<usize> {
+        let written_len = self
+            .try_write(&name, ino, type_)
+            .map_err(|_| FsError::InvalidParam)?;
+        Ok(written_len)
+    }
+}
+
+trait Dirent {
+    fn new(name: &str, ino: u64, type_: FileType) -> Self;
+    fn rec_len(&self) -> usize;
+    fn dump(&self, buf: &mut [u8], name: &str, type_: FileType) -> Result<()>;
+}
+
+/// Same with struct linux_dirent64
+#[repr(packed)] // Don't use 'C'. Or its size will align up to 8 bytes.
+#[derive(Debug, Clone, Copy)]
+struct LinuxDirent64 {
+    /// Inode number
+    pub ino: u64,
+    /// Offset to next structure
+    pub offset: u64,
+    /// Size of this dirent
+    pub rec_len: u16,
+    /// File type
+    pub type_: DirentType,
+    /// Filename (null-terminated)
+    pub name: [u8; 0],
+}
+
+impl Dirent for LinuxDirent64 {
+    fn new(name: &str, ino: u64, type_: FileType) -> Self {
+        let ori_len = core::mem::size_of::<Self>() + name.len() + 1;
+        let len = align_up(ori_len, 8); // align up to 8 bytes
+        Self {
+            ino,
+            offset: 0,
+            rec_len: len as u16,
+            type_: DirentType::from_file_type(type_),
+            name: [],
+        }
+    }
+
+    fn rec_len(&self) -> usize {
+        self.rec_len as usize
+    }
+
+    fn dump(&self, buf: &mut [u8], name: &str, _type_: FileType) -> Result<()> {
+        unsafe {
+            let ptr = buf.as_mut_ptr() as *mut Self;
+            ptr.write(*self);
+            let name_ptr = ptr.add(1) as _;
+            write_cstr(name_ptr, name);
+        }
+        Ok(())
+    }
+}
+
+/// Same with struct linux_dirent
+#[repr(packed)] // Don't use 'C'. Or its size will align up to 8 bytes.
+#[derive(Debug, Clone, Copy)]
+struct LinuxDirent {
+    /// Inode number
+    pub ino: u64,
+    /// Offset to next structure
+    pub offset: u64,
+    /// Size of this dirent
+    pub rec_len: u16,
+    /// Filename (null-terminated)
+    pub name: [u8; 0],
+    /*
+    /// Zero padding byte
+    pub pad: [u8],
+    /// File type
+    pub type_: DirentType,
+    */
+}
+
+impl Dirent for LinuxDirent {
+    fn new(name: &str, ino: u64, type_: FileType) -> Self {
+        let ori_len =
+            core::mem::size_of::<Self>() + name.len() + 1 + core::mem::size_of::<FileType>();
+        let len = align_up(ori_len, 8); // align up to 8 bytes
+        Self {
+            ino,
+            offset: 0,
+            rec_len: len as u16,
+            name: [],
+        }
+    }
+
+    fn rec_len(&self) -> usize {
+        self.rec_len as usize
+    }
+
+    fn dump(&self, buf: &mut [u8], name: &str, type_: FileType) -> Result<()> {
+        unsafe {
+            let ptr = buf.as_mut_ptr() as *mut Self;
+            ptr.write(*self);
+            let mut ptr = ptr.add(1) as *mut u8;
+            write_cstr(ptr, name);
+            // Pad zero bytes if necessary
+            ptr = ptr.add(name.len() + 1);
+            let mut remaining_len = {
+                let written_len = core::mem::size_of::<Self>() + name.len() + 1;
+                self.rec_len() - written_len
+            };
+            while remaining_len > 1 {
+                ptr.write(0);
+                ptr = ptr.add(1);
+                remaining_len -= 1;
+            }
+            // Write the type at the end
+            let dirent_type = DirentType::from_file_type(type_);
+            ptr.write(dirent_type as u8);
+        }
+        Ok(())
+    }
+}
+
+#[allow(non_camel_case_types)]
+#[derive(Debug, Clone, Copy)]
+#[repr(u8)]
+enum DirentType {
+    DT_UNKNOWN = 0,
+    DT_FIFO = 1,
+    DT_CHR = 2,
+    DT_DIR = 4,
+    DT_BLK = 6,
+    DT_REG = 8,
+    DT_LNK = 10,
+    DT_SOCK = 12,
+    DT_WHT = 14,
+}
+
+impl DirentType {
+    fn from_file_type(file_type: FileType) -> DirentType {
+        match file_type {
+            FileType::File => DirentType::DT_REG,
+            FileType::Dir => DirentType::DT_DIR,
+            FileType::SymLink => DirentType::DT_LNK,
+            FileType::CharDevice => DirentType::DT_CHR,
+            FileType::BlockDevice => DirentType::DT_BLK,
+            FileType::Socket => DirentType::DT_SOCK,
+            FileType::NamedPipe => DirentType::DT_FIFO,
+            _ => DirentType::DT_UNKNOWN,
+        }
+    }
+}
+
+/// Write a Rust string to C string
+unsafe fn write_cstr(ptr: *mut u8, s: &str) {
+    ptr.copy_from(s.as_ptr(), s.len());
+    ptr.add(s.len()).write(0);
+}

src/libos/src/fs/file_ops/mod.rs

@@ -5,7 +5,6 @@ pub use self::access::{do_faccessat, AccessibilityCheckFlags, AccessibilityCheck
 pub use self::chmod::{do_fchmod, do_fchmodat, FileMode};
 pub use self::chown::{do_fchown, do_fchownat, ChownFlags};
 pub use self::close::do_close;
-pub use self::dirent::{do_getdents, do_getdents64};
 pub use self::dup::{do_dup, do_dup2, do_dup3};
 pub use self::fallocate::do_fallocate;
 pub use self::fcntl::{do_fcntl, FcntlCmd};
@@ -13,6 +12,7 @@ pub use self::file_flags::{AccessMode, CreationFlags, StatusFlags};
 pub use self::flock::{Flock, FlockType};
 pub use self::fspath::{FsPath, AT_FDCWD};
 pub use self::fsync::{do_fdatasync, do_fsync};
+pub use self::getdents::{do_getdents, do_getdents64};
 pub use self::ioctl::{
     do_ioctl, occlum_ocall_ioctl, BuiltinIoctlNum, IfConf, IoctlCmd, StructuredIoctlArgType,
     StructuredIoctlNum,
@@ -35,7 +35,6 @@ mod access;
 mod chmod;
 mod chown;
 mod close;
-mod dirent;
 mod dup;
 mod fallocate;
 mod fcntl;
@@ -43,6 +42,7 @@ mod file_flags;
 mod flock;
 mod fspath;
 mod fsync;
+mod getdents;
 mod ioctl;
 mod link;
 mod lseek;

src/libos/src/fs/hostfs.rs

@@ -3,6 +3,7 @@ use alloc::sync::{Arc, Weak};
 use core::any::Any;
 use rcore_fs::vfs::*;
 use std::io::{Read, Seek, SeekFrom, Write};
+use std::os::unix::fs::{DirEntryExt, FileTypeExt};
 use std::path::{Path, PathBuf};
 use std::sync::{SgxMutex as Mutex, SgxMutexGuard as MutexGuard};
 use std::untrusted::fs;
@@ -209,6 +210,39 @@ impl INode for HNode {
         }
     }
 
+    fn iterate_entries(&self, ctx: &mut DirentWriterContext) -> Result<usize> {
+        if !self.path.is_dir() {
+            return Err(FsError::NotDir);
+        }
+        let idx = ctx.pos();
+        let mut total_written_len = 0;
+        for entry in try_std!(self.path.read_dir()).skip(idx) {
+            let entry = try_std!(entry);
+            let written_len = match ctx.write_entry(
+                &entry
+                    .file_name()
+                    .into_string()
+                    .map_err(|_| FsError::InvalidParam)?,
+                entry.ino(),
+                entry
+                    .file_type()
+                    .map_err(|_| FsError::InvalidParam)?
+                    .into_fs_filetype(),
+            ) {
+                Ok(written_len) => written_len,
+                Err(e) => {
+                    if total_written_len == 0 {
+                        return Err(e);
+                    } else {
+                        break;
+                    }
+                }
+            };
+            total_written_len += written_len;
+        }
+        Ok(total_written_len)
+    }
+
     fn io_control(&self, cmd: u32, data: usize) -> Result<()> {
         warn!("HostFS: io_control is unimplemented");
         Ok(())
@@ -265,6 +299,32 @@ impl IntoFsError for std::io::Error {
     }
 }
 
+trait IntoFsFileType {
+    fn into_fs_filetype(self) -> FileType;
+}
+
+impl IntoFsFileType for fs::FileType {
+    fn into_fs_filetype(self) -> FileType {
+        if self.is_dir() {
+            FileType::Dir
+        } else if self.is_file() {
+            FileType::File
+        } else if self.is_symlink() {
+            FileType::SymLink
+        } else if self.is_block_device() {
+            FileType::BlockDevice
+        } else if self.is_char_device() {
+            FileType::CharDevice
+        } else if self.is_fifo() {
+            FileType::NamedPipe
+        } else if self.is_socket() {
+            FileType::Socket
+        } else {
+            unimplemented!("unknown file type")
+        }
+    }
+}
+
 trait IntoFsMetadata {
     fn into_fs_metadata(self) -> Metadata;
 }

src/libos/src/fs/inode_file.rs

@@ -144,14 +144,15 @@ impl File for INodeFile {
         Ok(())
     }
 
-    fn read_entry(&self) -> Result<String> {
+    fn iterate_entries(&self, writer: &mut dyn DirentWriter) -> Result<usize> {
         if !self.access_mode.readable() {
             return_errno!(EACCES, "File not readable. Can't read entry.");
         }
         let mut offset = self.offset.lock().unwrap();
-        let name = self.inode.get_entry(*offset)?;
+        let mut dir_ctx = DirentWriterContext::new(*offset, writer);
-        *offset += 1;
+        let written_size = self.inode.iterate_entries(&mut dir_ctx)?;
-        Ok(name)
+        *offset = dir_ctx.pos();
+        Ok(written_size)
     }
 
     fn access_mode(&self) -> Result<AccessMode> {

src/libos/src/fs/mod.rs

@@ -1,7 +1,10 @@
 use super::*;
 
 use process;
-use rcore_fs::vfs::{FileSystem, FileType, FsError, INode, Metadata, Timespec, PATH_MAX};
+use rcore_fs::vfs::{
+    DirentWriter, DirentWriterContext, FileSystem, FileType, FsError, INode, Metadata, Timespec,
+    PATH_MAX,
+};
 use std;
 use std::any::Any;
 use std::fmt;