Prevent closing of standard descriptors through file objects (#1725)

* Prevent closing of standard descriptors through file objects

* Add test

* Enable closing of standard descriptors directly

* Add more tests

Author: BCSharp

Src/DLR

@@ -334,8 +334,8 @@ public static void chmod(CodeContext context, object? path, int mode, [ParamDict
         public static void close(CodeContext/*!*/ context, int fd) {
             PythonFileManager fileManager = context.LanguageContext.FileManager;
             if (fileManager.TryGetFileFromId(fd, out PythonIOModule.FileIO? file)) {
-                file.closefd = true;
-                file.close(context);
+                file.CloseStreams(fileManager);
+                fileManager.RemoveObjectOnId(fd);
             } else {
                 Stream stream = fileManager.GetStreamFromId(fd);
                 fileManager.RemoveObjectOnId(fd);
@@ -358,7 +358,7 @@ public static int dup(CodeContext/*!*/ context, int fd) {
 
             object obj = fileManager.GetObjectFromId(fd); // OSError if fd not valid
             if (obj is PythonIOModule.FileIO file) {
-                var file2 = new PythonIOModule.FileIO(context, file.fileno(context));
+                var file2 = new PythonIOModule.FileIO(context, file.fileno(context)) { closefd = false };
                 int fd2 = fileManager.AddFile(file2);
                 fileManager.EnsureRef(file._readStream);
                 fileManager.AddRef(file2._readStream);
@@ -391,7 +391,7 @@ public static int dup2(CodeContext/*!*/ context, int fd, int fd2) {
             // TODO: race condition: `open` or `dup` on another thread may occupy fd2 
 
             if (obj is PythonIOModule.FileIO file) {
-                var file2 = new PythonIOModule.FileIO(context, file.fileno(context));
+                var file2 = new PythonIOModule.FileIO(context, file.fileno(context)) { closefd = false };
                 fileManager.AddFile(fd2, file2);
                 fileManager.EnsureRef(file._readStream);
                 fileManager.AddRef(file2._readStream);
@@ -909,8 +909,8 @@ static Tuple<Stream, Stream> CreatePipeStreamsUnix() {
         public static PythonTuple pipe(CodeContext context) {
             var pipeStreams = CreatePipeStreams();
 
-            var inFile = new PythonIOModule.FileIO(context, pipeStreams.Item1);
-            var outFile = new PythonIOModule.FileIO(context, pipeStreams.Item2);
+            var inFile = new PythonIOModule.FileIO(context, pipeStreams.Item1) { closefd = false };
+            var outFile = new PythonIOModule.FileIO(context, pipeStreams.Item2) { closefd = false };
 
             return PythonTuple.MakeTuple(
                 context.LanguageContext.FileManager.AddFile(inFile),

Src/IronPython.Modules/nt.cs

@@ -64,6 +64,7 @@ internal FileIO(CodeContext/*!*/ context, Stream stream, ConsoleStreamType conso
                 : this(context, stream) {
                 IsConsole = true;
                 _consoleStreamType = consoleStreamType;
+                _closefd= false;
             }
 
             public FileIO(CodeContext/*!*/ context, int fd, string mode = "r", bool closefd = true, object opener = null)
@@ -92,7 +93,7 @@ public FileIO(CodeContext/*!*/ context, int fd, string mode = "r", bool closefd
                 }
 
                 _fd = fd;
-                _closefd = closefd;
+                _closefd = closefd && !SharedIO.IsConsoleStream(_readStream);
             }
 
             public FileIO(CodeContext/*!*/ context, string name, string mode = "r", bool closefd = true, object opener = null)
@@ -283,21 +284,25 @@ public override void close(CodeContext/*!*/ context) {
                         myManager?.RemoveObjectOnId(_fd);
                     }
 
-                    bool readStreamClosed = true;
-                    if (_readStream is not null) {
-                        if (myManager is not null) {
-                            readStreamClosed = myManager.DerefAndCloseIfLast(_readStream);
-                            if (readStreamClosed) {
-                                myManager.Remove(_readStream);
-                            }
-                        } else {
-                            _readStream.Close();
+                    CloseStreams(myManager);
+                }
+            }
+
+            internal void CloseStreams(PythonFileManager manager) {
+                bool readStreamClosed = true;
+                if (_readStream is not null) {
+                    if (manager is not null) {
+                        readStreamClosed = manager.DerefAndCloseIfLast(_readStream);
+                        if (readStreamClosed) {
+                            manager.Remove(_readStream);
                         }
+                    } else {
+                        _readStream.Close();
                     }
-                    if (_writeStream is not null && !ReferenceEquals(_readStream, _writeStream) && readStreamClosed) {
-                        _writeStream.Close();
-                        myManager?.Remove(_writeStream);
-                    }
+                }
+                if (_writeStream is not null && !ReferenceEquals(_readStream, _writeStream) && readStreamClosed) {
+                    _writeStream.Close();
+                    manager?.Remove(_writeStream);
                 }
             }
 

Src/IronPython/Modules/_fileio.cs

@@ -251,4 +251,21 @@ def test_stat_chdir(self):
         os.close(fd)
         os.unlink(test_filename)
 
+    def test_stdio_fd(self):
+        for file, fd, mode in [(sys.stdin, 0, 'r'), (sys.stdout, 1, 'w'), (sys.stderr, 2, 'w')]:
+            with self.subTest(fd=fd):
+                self.assertEqual(file.fileno(), fd)
+                self.assertFalse(file.buffer.raw.closefd)
+                with open(fd, mode=mode, closefd=True) as file2:
+                    # this fails in CPython if standard I/O is redirected
+                    self.assertFalse(file2.buffer.raw.closefd)
+                with open(fd, mode=mode, closefd=True) as file3:
+                    self.assertFalse(file3.buffer.raw.closefd)
+
+                fd2 = os.dup(fd)
+                self.assertNotEqual(fd2, fd)
+                with open(fd2, mode=mode, closefd=True) as file4:
+                    self.assertFalse(file4.buffer.raw.closefd)
+                os.close(fd2)
+
 run_test(__name__)