[libos] Refine the getdents syscall.

deps/sefs

@@ -1 +1 @@
-Subproject commit 98196fb62f64f0edeacc20d60c30aaaf4a290f70
+Subproject commit a771d5d37f2a21b02ee579bab85dc8e551d924e0

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

@@ -23,13 +23,13 @@ fn getdents_common<T: Dirent>(fd: FileDesc, buf: &mut [u8]) -> Result<usize> {
         return_errno!(ENOTDIR, "");
     }
     let mut writer = DirentBufWriter::<T>::new(buf);
-    let written_size = file_ref.iterate_entries(&mut writer)?;
+    let written_len = file_ref.iterate_entries(&mut writer)?;
-    Ok(written_size)
+    Ok(written_len)
 }
 
 struct DirentBufWriter<'a, T: Dirent> {
     buf: &'a mut [u8],
-    written_size: usize,
+    written_len: usize,
     phantom: PhantomData<T>,
 }
 
@@ -37,40 +37,34 @@ impl<'a, T: Dirent> DirentBufWriter<'a, T> {
     fn new(buf: &'a mut [u8]) -> Self {
         Self {
             buf,
-            written_size: 0,
+            written_len: 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(
+    fn write_entry(&mut self, name: &str, ino: u64, type_: FileType) -> rcore_fs::vfs::Result<()> {
-        &mut self,
+        let dirent: T = Dirent::new(name, ino, type_);
-        name: &str,
+        if self.buf.len() - self.written_len < dirent.rec_len() {
-        ino: u64,
+            return Err(FsError::InvalidParam);
-        type_: FileType,
+        }
-    ) -> rcore_fs::vfs::Result<usize> {
+        dirent
-        let written_len = self
+            .serialize(&mut self.buf[self.written_len..], name, type_)
-            .try_write(&name, ino, type_)
             .map_err(|_| FsError::InvalidParam)?;
-        Ok(written_len)
+        self.written_len += dirent.rec_len();
+        Ok(())
+    }
+
+    fn written_len(&self) -> usize {
+        self.written_len
     }
 }
 
 trait Dirent: Sync + Send {
     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<()>;
+    fn serialize(&self, buf: &mut [u8], name: &str, type_: FileType) -> Result<()>;
 }
 
 /// Same with struct linux_dirent64
@@ -106,7 +100,7 @@ impl Dirent for LinuxDirent64 {
         self.rec_len as usize
     }
 
-    fn dump(&self, buf: &mut [u8], name: &str, _type_: FileType) -> Result<()> {
+    fn serialize(&self, buf: &mut [u8], name: &str, _type_: FileType) -> Result<()> {
         unsafe {
             let ptr = buf.as_mut_ptr() as *mut Self;
             ptr.write(*self);
@@ -154,7 +148,7 @@ impl Dirent for LinuxDirent {
         self.rec_len as usize
     }
 
-    fn dump(&self, buf: &mut [u8], name: &str, type_: FileType) -> Result<()> {
+    fn serialize(&self, buf: &mut [u8], name: &str, type_: FileType) -> Result<()> {
         unsafe {
             let ptr = buf.as_mut_ptr() as *mut Self;
             ptr.write(*self);

src/libos/src/fs/hostfs.rs

@@ -269,10 +269,9 @@ impl INode for HNode {
             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(
+            if let Err(e) = ctx.write_entry(
                 &entry
                     .file_name()
                     .into_string()
@@ -283,18 +282,14 @@ impl INode for HNode {
                     .map_err(|_| FsError::InvalidParam)?
                     .into_fs_filetype(),
             ) {
-                Ok(written_len) => written_len,
+                if ctx.written_len() == 0 {
-                Err(e) => {
-                    if total_written_len == 0 {
                     return Err(e);
                 } else {
                     break;
                 }
-                }
             };
-            total_written_len += written_len;
         }
-        Ok(total_written_len)
+        Ok(ctx.written_len())
     }
 
     fn io_control(&self, cmd: u32, data: usize) -> Result<()> {

src/libos/src/fs/procfs/mod.rs

@@ -159,23 +159,22 @@ impl DirProcINode for LockedProcRootINode {
 
     fn iterate_entries(&self, mut ctx: &mut DirentWriterContext) -> vfs::Result<usize> {
         let file = self.0.read().unwrap();
-        let mut total_written_len = 0;
         let idx = ctx.pos();
 
         // Write first two special entries
         if idx == 0 {
             let this_inode = file.this.upgrade().unwrap();
-            write_inode_entry!(&mut ctx, ".", &this_inode, &mut total_written_len);
+            write_inode_entry!(&mut ctx, ".", &this_inode);
         }
         if idx <= 1 {
             let parent_inode = file.this.upgrade().unwrap();
-            write_inode_entry!(&mut ctx, "..", &parent_inode, &mut total_written_len);
+            write_inode_entry!(&mut ctx, "..", &parent_inode);
         }
 
         // Write the non volatile entries
         let skipped = if idx < 2 { 0 } else { idx - 2 };
         for (name, inode) in file.non_volatile_entries.iter().skip(skipped) {
-            write_inode_entry!(&mut ctx, name, inode, &mut total_written_len);
+            write_inode_entry!(&mut ctx, name, inode);
         }
 
         // Write the pid entries
@@ -192,11 +191,10 @@ impl DirProcINode for LockedProcRootINode {
                 &mut ctx,
                 &process.pid().to_string(),
                 PROC_INO,
-                vfs::FileType::Dir,
+                vfs::FileType::Dir
-                &mut total_written_len
             );
         }
 
-        Ok(total_written_len)
+        Ok(ctx.written_len())
     }
 }

src/libos/src/fs/procfs/pid/fd.rs

@@ -55,32 +55,24 @@ impl DirProcINode for LockedProcFdDirINode {
 
     fn iterate_entries(&self, mut ctx: &mut DirentWriterContext) -> vfs::Result<usize> {
         let file = self.0.read().unwrap();
-        let mut total_written_len = 0;
         let idx = ctx.pos();
 
         // Write first two special entries
-        write_first_two_entries!(idx, &mut ctx, &file, &mut total_written_len);
+        write_first_two_entries!(idx, &mut ctx, &file);
 
         // Write the fd entries
         let skipped = if idx < 2 { 0 } else { idx - 2 };
         let main_thread = match file.process_ref.main_thread() {
             Some(main_thread) => main_thread,
             None => {
-                return Ok(total_written_len);
+                return Ok(ctx.written_len());
             }
         };
         let fds = main_thread.files().lock().unwrap().fds();
         for fd in fds.iter().skip(skipped) {
-            write_entry!(
+            write_entry!(&mut ctx, &fd.to_string(), PROC_INO, vfs::FileType::SymLink);
-                &mut ctx,
-                &fd.to_string(),
-                PROC_INO,
-                vfs::FileType::SymLink,
-                &mut total_written_len
-            );
         }
-
+        Ok(ctx.written_len())
-        Ok(total_written_len)
     }
 }
 

src/libos/src/fs/procfs/pid/mod.rs

@@ -115,29 +115,21 @@ impl DirProcINode for LockedPidDirINode {
 
     fn iterate_entries(&self, mut ctx: &mut DirentWriterContext) -> vfs::Result<usize> {
         let file = self.0.read().unwrap();
-        let mut total_written_len = 0;
         let idx = ctx.pos();
 
         // Write first two special entries
-        write_first_two_entries!(idx, &mut ctx, &file, &mut total_written_len);
+        write_first_two_entries!(idx, &mut ctx, &file);
 
         // Write the normal entries
         let skipped = if idx < 2 { 0 } else { idx - 2 };
         for (name, inode) in file.entries.iter().skip(skipped) {
-            write_inode_entry!(&mut ctx, name, inode, &mut total_written_len);
+            write_inode_entry!(&mut ctx, name, inode);
         }
 
         // Write the fd entry
         if idx <= 2 + file.entries.len() {
-            write_entry!(
+            write_entry!(&mut ctx, "fd", PROC_INO, vfs::FileType::Dir);
-                &mut ctx,
-                "fd",
-                PROC_INO,
-                vfs::FileType::Dir,
-                &mut total_written_len
-            );
         }
-
+        Ok(ctx.written_len())
-        Ok(total_written_len)
     }
 }

src/libos/src/fs/procfs/proc_inode/mod.rs

@@ -66,52 +66,45 @@ macro_rules! impl_inode_for_file_or_symlink {
 
 #[macro_export]
 macro_rules! write_first_two_entries {
-    ($idx: expr, $ctx:expr, $file:expr, $total_written:expr) => {
+    ($idx: expr, $ctx:expr, $file:expr) => {
         let idx = $idx;
         let file = $file;
 
         if idx == 0 {
             let this_inode = file.this.upgrade().unwrap();
-            write_inode_entry!($ctx, ".", &this_inode, $total_written);
+            write_inode_entry!($ctx, ".", &this_inode);
         }
         if idx <= 1 {
-            write_inode_entry!($ctx, "..", &file.parent, $total_written);
+            write_inode_entry!($ctx, "..", &file.parent);
         }
     };
 }
 
 #[macro_export]
 macro_rules! write_inode_entry {
-    ($ctx:expr, $name:expr, $inode:expr, $total_written:expr) => {
+    ($ctx:expr, $name:expr, $inode:expr) => {
         let ctx = $ctx;
         let name = $name;
         let ino = $inode.metadata()?.inode;
         let type_ = $inode.metadata()?.type_;
-        let total_written = $total_written;
 
-        write_entry!(ctx, name, ino, type_, total_written);
+        write_entry!(ctx, name, ino, type_);
     };
 }
 
 #[macro_export]
 macro_rules! write_entry {
-    ($ctx:expr, $name:expr, $ino:expr, $type_:expr, $total_written:expr) => {
+    ($ctx:expr, $name:expr, $ino:expr, $type_:expr) => {
         let ctx = $ctx;
         let name = $name;
         let ino = $ino;
         let type_ = $type_;
-        let total_written = $total_written;
 
-        match ctx.write_entry(name, ino as u64, type_) {
+        if let Err(e) = ctx.write_entry(name, ino as u64, type_) {
-            Ok(written_len) => {
+            if ctx.written_len() == 0 {
-                *total_written += written_len;
-            }
-            Err(e) => {
-                if *total_written == 0 {
                 return Err(e);
             } else {
-                    return Ok(*total_written);
+                return Ok(ctx.written_len());
-                }
             }
         }
     };