From c6f9b2b7f5f3640ce8aeac4aff67f75821891d81 Mon Sep 17 00:00:00 2001
From: Steve Dower <steve.dower@microsoft.com>
Date: Sat, 8 Oct 2016 12:37:33 -0700
Subject: Issue #28162: Fixes Ctrl+Z handling in console readall()

---
 Lib/test/test_winconsoleio.py | 38 +++++++++++++++++++--------------
 Modules/_io/winconsoleio.c    | 49 +++++++++++++++++++++++++------------------
 2 files changed, 51 insertions(+), 36 deletions(-)

diff --git a/Lib/test/test_winconsoleio.py b/Lib/test/test_winconsoleio.py
index f2cccbc..b1a2f7a 100644
--- a/Lib/test/test_winconsoleio.py
+++ b/Lib/test/test_winconsoleio.py
@@ -107,16 +107,15 @@ class WindowsConsoleIOTests(unittest.TestCase):
         source = 'ϼўТλФЙ\r\n'.encode('utf-16-le')
         expected = 'ϼўТλФЙ\r\n'.encode('utf-8')
         for read_count in range(1, 16):
-            stdin = open('CONIN$', 'rb', buffering=0)
-            write_input(stdin, source)
+            with open('CONIN$', 'rb', buffering=0) as stdin:
+                write_input(stdin, source)
 
-            actual = b''
-            while not actual.endswith(b'\n'):
-                b = stdin.read(read_count)
-                actual += b
+                actual = b''
+                while not actual.endswith(b'\n'):
+                    b = stdin.read(read_count)
+                    actual += b
 
-            self.assertEqual(actual, expected, 'stdin.read({})'.format(read_count))
-            stdin.close()
+                self.assertEqual(actual, expected, 'stdin.read({})'.format(read_count))
 
     def test_partial_surrogate_reads(self):
         # Test that reading less than 1 full character works when stdin
@@ -125,17 +124,24 @@ class WindowsConsoleIOTests(unittest.TestCase):
         source = '\U00101FFF\U00101001\r\n'.encode('utf-16-le')
         expected = '\U00101FFF\U00101001\r\n'.encode('utf-8')
         for read_count in range(1, 16):
-            stdin = open('CONIN$', 'rb', buffering=0)
-            write_input(stdin, source)
+            with open('CONIN$', 'rb', buffering=0) as stdin:
+                write_input(stdin, source)
 
-            actual = b''
-            while not actual.endswith(b'\n'):
-                b = stdin.read(read_count)
-                actual += b
+                actual = b''
+                while not actual.endswith(b'\n'):
+                    b = stdin.read(read_count)
+                    actual += b
 
-            self.assertEqual(actual, expected, 'stdin.read({})'.format(read_count))
-            stdin.close()
+                self.assertEqual(actual, expected, 'stdin.read({})'.format(read_count))
 
+    def test_ctrl_z(self):
+        with open('CONIN$', 'rb', buffering=0) as stdin:
+            source = '\xC4\x1A\r\n'.encode('utf-16-le')
+            expected = '\xC4'.encode('utf-8')
+            write_input(stdin, source)
+            a, b = stdin.read(1), stdin.readall()
+            self.assertEqual(expected[0:1], a)
+            self.assertEqual(expected[1:], b)
 
 if __name__ == "__main__":
     unittest.main()
diff --git a/Modules/_io/winconsoleio.c b/Modules/_io/winconsoleio.c
index ee7a1b2..4666a38 100644
--- a/Modules/_io/winconsoleio.c
+++ b/Modules/_io/winconsoleio.c
@@ -816,44 +816,53 @@ _io__WindowsConsoleIO_readall_impl(winconsoleio *self)
 
         PyMem_Free(subbuf);
 
-        /* when the read starts with ^Z or is empty we break */
-        if (n == 0 || buf[len] == '\x1a')
+        /* when the read is empty we break */
+        if (n == 0)
             break;
 
         len += n;
     }
 
-    if (len == 0 || buf[0] == '\x1a' && _buflen(self) == 0) {
+    if (len == 0 && _buflen(self) == 0) {
         /* when the result starts with ^Z we return an empty buffer */
         PyMem_Free(buf);
         return PyBytes_FromStringAndSize(NULL, 0);
     }
 
-    Py_BEGIN_ALLOW_THREADS
-    bytes_size = WideCharToMultiByte(CP_UTF8, 0, buf, len,
-        NULL, 0, NULL, NULL);
-    Py_END_ALLOW_THREADS
+    if (len) {
+        Py_BEGIN_ALLOW_THREADS
+        bytes_size = WideCharToMultiByte(CP_UTF8, 0, buf, len,
+            NULL, 0, NULL, NULL);
+        Py_END_ALLOW_THREADS
 
-    if (!bytes_size) {
-        DWORD err = GetLastError();
-        PyMem_Free(buf);
-        return PyErr_SetFromWindowsErr(err);
+        if (!bytes_size) {
+            DWORD err = GetLastError();
+            PyMem_Free(buf);
+            return PyErr_SetFromWindowsErr(err);
+        }
+    } else {
+        bytes_size = 0;
     }
 
     bytes_size += _buflen(self);
     bytes = PyBytes_FromStringAndSize(NULL, bytes_size);
     rn = _copyfrombuf(self, PyBytes_AS_STRING(bytes), bytes_size);
 
-    Py_BEGIN_ALLOW_THREADS
-    bytes_size = WideCharToMultiByte(CP_UTF8, 0, buf, len,
-        &PyBytes_AS_STRING(bytes)[rn], bytes_size - rn, NULL, NULL);
-    Py_END_ALLOW_THREADS
+    if (len) {
+        Py_BEGIN_ALLOW_THREADS
+        bytes_size = WideCharToMultiByte(CP_UTF8, 0, buf, len,
+            &PyBytes_AS_STRING(bytes)[rn], bytes_size - rn, NULL, NULL);
+        Py_END_ALLOW_THREADS
 
-    if (!bytes_size) {
-        DWORD err = GetLastError();
-        PyMem_Free(buf);
-        Py_CLEAR(bytes);
-        return PyErr_SetFromWindowsErr(err);
+        if (!bytes_size) {
+            DWORD err = GetLastError();
+            PyMem_Free(buf);
+            Py_CLEAR(bytes);
+            return PyErr_SetFromWindowsErr(err);
+        }
+
+        /* add back the number of preserved bytes */
+        bytes_size += rn;
     }
 
     PyMem_Free(buf);
-- 
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