change set_fdflags to reopen_with_fdflags

crates/wasi-c2/cap-std-sync/src/file.rs

@@ -38,8 +38,8 @@ impl WasiFile for File {
         // XXX get_fdflags is not implemented but lets lie rather than panic:
         Ok(FdFlags::empty())
     }
-    fn set_fdflags(&self, _fdflags: FdFlags) -> Result<(), Error> {
+    fn reopen_with_fdflags(&self, _fdflags: FdFlags) -> Result<Box<dyn WasiFile>, Error> {
-        todo!("set_fdflags is not implemented")
+        todo!("reopen_with_fdflags is not implemented")
     }
     fn get_filestat(&self) -> Result<Filestat, Error> {
         let meta = self.0.metadata()?;

crates/wasi-c2/cap-std-sync/src/stdio.rs

@@ -39,9 +39,8 @@ impl WasiFile for Stdin {
         // XXX get_fdflags is not implemented but lets lie rather than panic:
         Ok(FdFlags::empty())
     }
-    fn set_fdflags(&self, _fdflags: FdFlags) -> Result<(), Error> {
+    fn reopen_with_fdflags(&self, _fdflags: FdFlags) -> Result<Box<dyn WasiFile>, Error> {
-        // XXX
+        Err(Error::Badf)
-        Err(Error::Perm)
     }
     fn get_filestat(&self) -> Result<Filestat, Error> {
         let meta = self.0.as_file_view().metadata()?;
@@ -131,9 +130,8 @@ macro_rules! wasi_file_write_impl {
                 // XXX get_fdflags is not implemented but lets lie rather than panic:
                 Ok(FdFlags::empty())
             }
-            fn set_fdflags(&self, _fdflags: FdFlags) -> Result<(), Error> {
+            fn reopen_with_fdflags(&self, _fdflags: FdFlags) -> Result<Box<dyn WasiFile>, Error> {
-                // XXX
+                Err(Error::Badf)
-                Err(Error::Perm)
             }
             fn get_filestat(&self) -> Result<Filestat, Error> {
                 // XXX can unsafe-io give a way to get metadata?

crates/wasi-c2/src/file.rs

@@ -10,7 +10,7 @@ pub trait WasiFile {
     fn sync(&self) -> Result<(), Error>; // file op
     fn get_filetype(&self) -> Result<FileType, Error>; // file op
     fn get_fdflags(&self) -> Result<FdFlags, Error>; // file op
-    fn set_fdflags(&self, _flags: FdFlags) -> Result<(), Error>;
+    fn reopen_with_fdflags(&self, flags: FdFlags) -> Result<Box<dyn WasiFile>, Error>; // file op
     fn get_filestat(&self) -> Result<Filestat, Error>; // split out get_length as a read & write op, rest is a file op
     fn set_filestat_size(&self, _size: u64) -> Result<(), Error>; // write op
     fn advise(
@@ -83,11 +83,23 @@ pub struct Filestat {
 
 pub(crate) trait TableFileExt {
     fn get_file(&self, fd: u32) -> Result<Ref<FileEntry>, Error>;
+    fn update_file_in_place<F>(&mut self, fd: u32, f: F) -> Result<(), Error>
+    where
+        F: FnOnce(&dyn WasiFile) -> Result<Box<dyn WasiFile>, Error>;
 }
 impl TableFileExt for crate::table::Table {
     fn get_file(&self, fd: u32) -> Result<Ref<FileEntry>, Error> {
         self.get(fd)
     }
+    fn update_file_in_place<F>(&mut self, fd: u32, f: F) -> Result<(), Error>
+    where
+        F: FnOnce(&dyn WasiFile) -> Result<Box<dyn WasiFile>, Error>,
+    {
+        self.update_in_place(fd, |FileEntry { caps, file }| {
+            let file = f(file.deref())?;
+            Ok(FileEntry { caps, file })
+        })
+    }
 }
 
 pub(crate) struct FileEntry {

crates/wasi-c2/src/pipe.rs

@@ -114,8 +114,8 @@ impl<R: Read + Any> WasiFile for ReadPipe<R> {
     fn get_fdflags(&self) -> Result<FdFlags, Error> {
         Ok(FdFlags::empty())
     }
-    fn set_fdflags(&self, _fdflags: FdFlags) -> Result<(), Error> {
+    fn reopen_with_fdflags(&self, _fdflags: FdFlags) -> Result<Box<dyn WasiFile>, Error> {
-        Err(Error::Perm)
+        Err(Error::Badf)
     }
     fn get_filestat(&self) -> Result<Filestat, Error> {
         Ok(Filestat {
@@ -250,8 +250,8 @@ impl<W: Write + Any> WasiFile for WritePipe<W> {
     fn get_fdflags(&self) -> Result<FdFlags, Error> {
         Ok(FdFlags::APPEND)
     }
-    fn set_fdflags(&self, _fdflags: FdFlags) -> Result<(), Error> {
+    fn reopen_with_fdflags(&self, _fdflags: FdFlags) -> Result<Box<dyn WasiFile>, Error> {
-        Err(Error::Perm)
+        Err(Error::Badf)
     }
     fn get_filestat(&self) -> Result<Filestat, Error> {
         Ok(Filestat {

crates/wasi-c2/src/snapshots/preview_1.rs

@@ -272,11 +272,11 @@ impl<'a> wasi_snapshot_preview1::WasiSnapshotPreview1 for WasiCtx {
     }
 
     fn fd_fdstat_set_flags(&self, fd: types::Fd, flags: types::Fdflags) -> Result<(), Error> {
-        self.table()
+        let mut table = self.table();
-            .get_file(u32::from(fd))?
+        let fd = u32::from(fd);
-            .get_cap(FileCaps::FDSTAT_SET_FLAGS)?
+        let table_check = table.get_file(fd)?.get_cap(FileCaps::FDSTAT_SET_FLAGS)?;
-            .set_fdflags(FdFlags::from(&flags))?;
+        drop(table_check);
-        Ok(())
+        table.update_file_in_place(fd, |f| f.reopen_with_fdflags(FdFlags::from(&flags)))
     }
 
     fn fd_fdstat_set_rights(

crates/wasi-c2/src/table.rs

@@ -78,11 +78,23 @@ impl Table {
                 Err(Error::Exist) // Does exist, but borrowed
             }
         } else {
-            Err(Error::Exist) // Does not exist
+            Err(Error::Badf) // Does not exist
         }
     }
 
     pub fn delete(&mut self, key: u32) -> Option<Box<dyn Any>> {
         self.map.remove(&key).map(|rc| RefCell::into_inner(rc))
     }
+
+    pub fn update_in_place<T, F>(&mut self, key: u32, f: F) -> Result<(), Error>
+    where
+        T: Any + Sized,
+        F: FnOnce(T) -> Result<T, Error>,
+    {
+        let entry = self.delete(key).ok_or(Error::Badf)?;
+        let downcast = entry.downcast::<T>().map_err(|_| Error::Exist)?;
+        let new = f(*downcast)?;
+        self.insert_at(key, Box::new(new));
+        Ok(())
+    }
 }