close file descriptor after reading the directory entries

library/std/src/sys/pal/hermit/fs.rs

@@ -509,7 +509,6 @@ impl FromRawFd for File {
 
 pub fn readdir(path: &Path) -> io::Result<ReadDir> {
     let fd_raw = run_path_with_cstr(path, |path| cvt(unsafe { abi::opendir(path.as_ptr()) }))?;
-    let fd = unsafe { FileDesc::from_raw_fd(fd_raw as i32) };
     let root = path.to_path_buf();
 
     // read all director entries
@@ -519,17 +518,22 @@ pub fn readdir(path: &Path) -> io::Result<ReadDir> {
         // reserve memory to receive all directory entries
         vec.resize(sz, 0);
 
-        let readlen =
-            unsafe { abi::getdents64(fd.as_raw_fd(), vec.as_mut_ptr() as *mut dirent64, sz) };
+        let readlen = unsafe { abi::getdents64(fd_raw, vec.as_mut_ptr() as *mut dirent64, sz) };
         if readlen > 0 {
             // shrink down to the minimal size
             vec.resize(readlen.try_into().unwrap(), 0);
+            unsafe {
+                abi::close(fd_raw);
+            }
             break;
         }
 
         // if the buffer is too small, getdents64 returns EINVAL
         // otherwise, getdents64 returns an error number
         if readlen != (-abi::errno::EINVAL).into() {
+            unsafe {
+                abi::close(fd_raw);
+            }
             return Err(Error::from_raw_os_error(readlen.try_into().unwrap()));
         }
 
@@ -539,6 +543,9 @@ pub fn readdir(path: &Path) -> io::Result<ReadDir> {
         // 1 MB for directory entries should be enough
         // stop here to avoid an endless loop
         if sz > 0x100000 {
+            unsafe {
+                abi::close(fd_raw);
+            }
             return Err(Error::from(ErrorKind::Uncategorized));
         }
     }